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* [PATCH v5 6/6] docs: trusted-encryped: add PKWM as a new trust source
From: Srish Srinivasan @ 2026-01-27 14:52 UTC (permalink / raw)
  To: linux-integrity, keyrings, linuxppc-dev
  Cc: maddy, mpe, npiggin, christophe.leroy, James.Bottomley, jarkko,
	zohar, nayna, rnsastry, linux-kernel, linux-security-module,
	ssrish
In-Reply-To: <20260127145228.48320-1-ssrish@linux.ibm.com>

From: Nayna Jain <nayna@linux.ibm.com>

Update Documentation/security/keys/trusted-encrypted.rst and Documentation/
admin-guide/kernel-parameters.txt with PowerVM Key Wrapping Module (PKWM)
as a new trust source

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Srish Srinivasan <ssrish@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
---
 .../admin-guide/kernel-parameters.txt         |  1 +
 .../security/keys/trusted-encrypted.rst       | 50 +++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1058f2a6d6a8..aac15079b33d 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -7790,6 +7790,7 @@ Kernel parameters
 			- "tee"
 			- "caam"
 			- "dcp"
+			- "pkwm"
 			If not specified then it defaults to iterating through
 			the trust source list starting with TPM and assigns the
 			first trust source as a backend which is initialized
diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
index eae6a36b1c9a..ddff7c7c2582 100644
--- a/Documentation/security/keys/trusted-encrypted.rst
+++ b/Documentation/security/keys/trusted-encrypted.rst
@@ -81,6 +81,14 @@ safe.
          and the UNIQUE key. Default is to use the UNIQUE key, but selecting
          the OTP key can be done via a module parameter (dcp_use_otp_key).
 
+     (5) PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore)
+
+         Rooted to a unique, per-LPAR key, which is derived from a system-wide,
+         randomly generated LPAR root key. Both the per-LPAR keys and the LPAR
+         root key are stored in hypervisor-owned secure memory at runtime,
+         and the LPAR root key is additionally persisted in secure locations
+         such as the processor SEEPROMs and encrypted NVRAM.
+
   *  Execution isolation
 
      (1) TPM
@@ -102,6 +110,14 @@ safe.
          environment. Only basic blob key encryption is executed there.
          The actual key sealing/unsealing is done on main processor/kernel space.
 
+     (5) PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore)
+
+         Fixed set of cryptographic operations done on on-chip hardware
+         cryptographic acceleration unit NX. Keys for wrapping and unwrapping
+         are managed by PowerVM Platform KeyStore, which stores keys in an
+         isolated in-memory copy in secure hypervisor memory, as well as in a
+         persistent copy in hypervisor-encrypted NVRAM.
+
   * Optional binding to platform integrity state
 
      (1) TPM
@@ -129,6 +145,11 @@ safe.
          Relies on Secure/Trusted boot process (called HAB by vendor) for
          platform integrity.
 
+     (5) PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore)
+
+         Relies on secure and trusted boot process of IBM Power systems for
+         platform integrity.
+
   *  Interfaces and APIs
 
      (1) TPM
@@ -149,6 +170,11 @@ safe.
          Vendor-specific API that is implemented as part of the DCP crypto driver in
          ``drivers/crypto/mxs-dcp.c``.
 
+     (5) PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore)
+
+         Platform Keystore has well documented interfaces in PAPR document.
+         Refer to ``Documentation/arch/powerpc/papr_hcalls.rst``
+
   *  Threat model
 
      The strength and appropriateness of a particular trust source for a given
@@ -191,6 +217,10 @@ selected trust source:
      a dedicated hardware RNG that is independent from DCP which can be enabled
      to back the kernel RNG.
 
+   * PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore)
+
+     The normal kernel random number generator is used to generate keys.
+
 Users may override this by specifying ``trusted.rng=kernel`` on the kernel
 command-line to override the used RNG with the kernel's random number pool.
 
@@ -321,6 +351,26 @@ Usage::
 specific to this DCP key-blob implementation.  The key length for new keys is
 always in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits).
 
+Trusted Keys usage: PKWM
+------------------------
+
+Usage::
+
+    keyctl add trusted name "new keylen [options]" ring
+    keyctl add trusted name "load hex_blob" ring
+    keyctl print keyid
+
+    options:
+       wrap_flags=   ascii hex value of security policy requirement
+                       0x00: no secure boot requirement (default)
+                       0x01: require secure boot to be in either audit or
+                             enforced mode
+                       0x02: require secure boot to be in enforced mode
+
+"keyctl print" returns an ASCII hex copy of the sealed key, which is in format
+specific to PKWM key-blob implementation.  The key length for new keys is
+always in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits).
+
 Encrypted Keys usage
 --------------------
 
-- 
2.47.3


^ permalink raw reply related

* [PATCH v5 5/6] keys/trusted_keys: establish PKWM as a trusted source
From: Srish Srinivasan @ 2026-01-27 14:52 UTC (permalink / raw)
  To: linux-integrity, keyrings, linuxppc-dev
  Cc: maddy, mpe, npiggin, christophe.leroy, James.Bottomley, jarkko,
	zohar, nayna, rnsastry, linux-kernel, linux-security-module,
	ssrish
In-Reply-To: <20260127145228.48320-1-ssrish@linux.ibm.com>

The wrapping key does not exist by default and is generated by the
hypervisor as a part of PKWM initialization. This key is then persisted by
the hypervisor and is used to wrap trusted keys. These are variable length
symmetric keys, which in the case of PowerVM Key Wrapping Module (PKWM) are
generated using the kernel RNG. PKWM can be used as a trust source through
the following example keyctl commands:

keyctl add trusted my_trusted_key "new 32" @u

Use the wrap_flags command option to set the secure boot requirement for
the wrapping request through the following keyctl commands

case1: no secure boot requirement. (default)
keyctl usage: keyctl add trusted my_trusted_key "new 32" @u
	      OR
	      keyctl add trusted my_trusted_key "new 32 wrap_flags=0x00" @u

case2: secure boot required to in either audit or enforce mode. set bit 0
keyctl usage: keyctl add trusted my_trusted_key "new 32 wrap_flags=0x01" @u

case3: secure boot required to be in enforce mode. set bit 1
keyctl usage: keyctl add trusted my_trusted_key "new 32 wrap_flags=0x02" @u

NOTE:
-> Setting the secure boot requirement is NOT a must.
-> Only either of the secure boot requirement options should be set. Not
both.
-> All the other bits are required to be not set.
-> Set the kernel parameter trusted.source=pkwm to choose PKWM as the
backend for trusted keys implementation.
-> CONFIG_PSERIES_PLPKS must be enabled to build PKWM.

Add PKWM, which is a combination of IBM PowerVM and Power LPAR Platform
KeyStore, as a new trust source for trusted keys.

Signed-off-by: Srish Srinivasan <ssrish@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
---
 MAINTAINERS                               |   9 +
 include/keys/trusted-type.h               |   7 +-
 include/keys/trusted_pkwm.h               |  33 ++++
 security/keys/trusted-keys/Kconfig        |   8 +
 security/keys/trusted-keys/Makefile       |   2 +
 security/keys/trusted-keys/trusted_core.c |   6 +-
 security/keys/trusted-keys/trusted_pkwm.c | 190 ++++++++++++++++++++++
 7 files changed, 253 insertions(+), 2 deletions(-)
 create mode 100644 include/keys/trusted_pkwm.h
 create mode 100644 security/keys/trusted-keys/trusted_pkwm.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 67db88b04537..7ffa45b903d6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14014,6 +14014,15 @@ S:	Supported
 F:	include/keys/trusted_dcp.h
 F:	security/keys/trusted-keys/trusted_dcp.c
 
+KEYS-TRUSTED-PLPKS
+M:	Srish Srinivasan <ssrish@linux.ibm.com>
+M:	Nayna Jain <nayna@linux.ibm.com>
+L:	linux-integrity@vger.kernel.org
+L:	keyrings@vger.kernel.org
+S:	Supported
+F:	include/keys/trusted_pkwm.h
+F:	security/keys/trusted-keys/trusted_pkwm.c
+
 KEYS-TRUSTED-TEE
 M:	Sumit Garg <sumit.garg@kernel.org>
 L:	linux-integrity@vger.kernel.org
diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
index 4eb64548a74f..03527162613f 100644
--- a/include/keys/trusted-type.h
+++ b/include/keys/trusted-type.h
@@ -19,7 +19,11 @@
 
 #define MIN_KEY_SIZE			32
 #define MAX_KEY_SIZE			128
-#define MAX_BLOB_SIZE			512
+#if IS_ENABLED(CONFIG_TRUSTED_KEYS_PKWM)
+#define MAX_BLOB_SIZE			1152
+#else
+#define MAX_BLOB_SIZE                   512
+#endif
 #define MAX_PCRINFO_SIZE		64
 #define MAX_DIGEST_SIZE			64
 
@@ -46,6 +50,7 @@ struct trusted_key_options {
 	uint32_t policydigest_len;
 	unsigned char policydigest[MAX_DIGEST_SIZE];
 	uint32_t policyhandle;
+	void *private;
 };
 
 struct trusted_key_ops {
diff --git a/include/keys/trusted_pkwm.h b/include/keys/trusted_pkwm.h
new file mode 100644
index 000000000000..4035b9776394
--- /dev/null
+++ b/include/keys/trusted_pkwm.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PKWM_TRUSTED_KEY_H
+#define __PKWM_TRUSTED_KEY_H
+
+#include <keys/trusted-type.h>
+#include <linux/bitops.h>
+#include <linux/printk.h>
+
+extern struct trusted_key_ops pkwm_trusted_key_ops;
+
+struct trusted_pkwm_options {
+	u16 wrap_flags;
+};
+
+static inline void dump_options(struct trusted_key_options *o)
+{
+	const struct trusted_pkwm_options *pkwm;
+	bool sb_audit_or_enforce_bit;
+	bool sb_enforce_bit;
+
+	pkwm = o->private;
+	sb_audit_or_enforce_bit = pkwm->wrap_flags & BIT(0);
+	sb_enforce_bit = pkwm->wrap_flags & BIT(1);
+
+	if (sb_audit_or_enforce_bit)
+		pr_debug("secure boot mode required: audit or enforce");
+	else if (sb_enforce_bit)
+		pr_debug("secure boot mode required: enforce");
+	else
+		pr_debug("secure boot mode required: disabled");
+}
+
+#endif
diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig
index 204a68c1429d..9e00482d886a 100644
--- a/security/keys/trusted-keys/Kconfig
+++ b/security/keys/trusted-keys/Kconfig
@@ -46,6 +46,14 @@ config TRUSTED_KEYS_DCP
 	help
 	  Enable use of NXP's DCP (Data Co-Processor) as trusted key backend.
 
+config TRUSTED_KEYS_PKWM
+	bool "PKWM-based trusted keys"
+	depends on PSERIES_PLPKS >= TRUSTED_KEYS
+	default y
+	select HAVE_TRUSTED_KEYS
+	help
+	  Enable use of IBM PowerVM Key Wrapping Module (PKWM) as a trusted key backend.
+
 if !HAVE_TRUSTED_KEYS
 	comment "No trust source selected!"
 endif
diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile
index f0f3b27f688b..5fc053a21dad 100644
--- a/security/keys/trusted-keys/Makefile
+++ b/security/keys/trusted-keys/Makefile
@@ -16,3 +16,5 @@ trusted-$(CONFIG_TRUSTED_KEYS_TEE) += trusted_tee.o
 trusted-$(CONFIG_TRUSTED_KEYS_CAAM) += trusted_caam.o
 
 trusted-$(CONFIG_TRUSTED_KEYS_DCP) += trusted_dcp.o
+
+trusted-$(CONFIG_TRUSTED_KEYS_PKWM) += trusted_pkwm.o
diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
index b1680ee53f86..2d328de170e8 100644
--- a/security/keys/trusted-keys/trusted_core.c
+++ b/security/keys/trusted-keys/trusted_core.c
@@ -12,6 +12,7 @@
 #include <keys/trusted_caam.h>
 #include <keys/trusted_dcp.h>
 #include <keys/trusted_tpm.h>
+#include <keys/trusted_pkwm.h>
 #include <linux/capability.h>
 #include <linux/err.h>
 #include <linux/init.h>
@@ -31,7 +32,7 @@ MODULE_PARM_DESC(rng, "Select trusted key RNG");
 
 static char *trusted_key_source;
 module_param_named(source, trusted_key_source, charp, 0);
-MODULE_PARM_DESC(source, "Select trusted keys source (tpm, tee, caam or dcp)");
+MODULE_PARM_DESC(source, "Select trusted keys source (tpm, tee, caam, dcp or pkwm)");
 
 static const struct trusted_key_source trusted_key_sources[] = {
 #if defined(CONFIG_TRUSTED_KEYS_TPM)
@@ -46,6 +47,9 @@ static const struct trusted_key_source trusted_key_sources[] = {
 #if defined(CONFIG_TRUSTED_KEYS_DCP)
 	{ "dcp", &dcp_trusted_key_ops },
 #endif
+#if defined(CONFIG_TRUSTED_KEYS_PKWM)
+	{ "pkwm", &pkwm_trusted_key_ops },
+#endif
 };
 
 DEFINE_STATIC_CALL_NULL(trusted_key_seal, *trusted_key_sources[0].ops->seal);
diff --git a/security/keys/trusted-keys/trusted_pkwm.c b/security/keys/trusted-keys/trusted_pkwm.c
new file mode 100644
index 000000000000..4f391b77a907
--- /dev/null
+++ b/security/keys/trusted-keys/trusted_pkwm.c
@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 IBM Corporation, Srish Srinivasan <ssrish@linux.ibm.com>
+ */
+
+#include <keys/trusted_pkwm.h>
+#include <keys/trusted-type.h>
+#include <linux/build_bug.h>
+#include <linux/key-type.h>
+#include <linux/parser.h>
+#include <asm/plpks.h>
+
+enum {
+	Opt_err,
+	Opt_wrap_flags,
+};
+
+static const match_table_t key_tokens = {
+	{Opt_wrap_flags, "wrap_flags=%s"},
+	{Opt_err, NULL}
+};
+
+static int getoptions(char *datablob, struct trusted_key_options *opt)
+{
+	substring_t args[MAX_OPT_ARGS];
+	char *p = datablob;
+	int token;
+	int res;
+	u16 wrap_flags;
+	unsigned long token_mask = 0;
+	struct trusted_pkwm_options *pkwm;
+
+	if (!datablob)
+		return 0;
+
+	pkwm = opt->private;
+
+	while ((p = strsep(&datablob, " \t"))) {
+		if (*p == '\0' || *p == ' ' || *p == '\t')
+			continue;
+
+		token = match_token(p, key_tokens, args);
+		if (test_and_set_bit(token, &token_mask))
+			return -EINVAL;
+
+		switch (token) {
+		case Opt_wrap_flags:
+			res = kstrtou16(args[0].from, 16, &wrap_flags);
+			if (res < 0 || wrap_flags > 2)
+				return -EINVAL;
+			pkwm->wrap_flags = wrap_flags;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+static struct trusted_key_options *trusted_options_alloc(void)
+{
+	struct trusted_key_options *options;
+	struct trusted_pkwm_options *pkwm;
+
+	options = kzalloc(sizeof(*options), GFP_KERNEL);
+
+	if (options) {
+		pkwm = kzalloc(sizeof(*pkwm), GFP_KERNEL);
+
+		if (!pkwm) {
+			kfree_sensitive(options);
+			options = NULL;
+		} else {
+			options->private = pkwm;
+		}
+	}
+
+	return options;
+}
+
+static int trusted_pkwm_seal(struct trusted_key_payload *p, char *datablob)
+{
+	struct trusted_key_options *options = NULL;
+	struct trusted_pkwm_options *pkwm = NULL;
+	u8 *input_buf, *output_buf;
+	u32 output_len, input_len;
+	int rc;
+
+	options = trusted_options_alloc();
+
+	if (!options)
+		return -ENOMEM;
+
+	rc = getoptions(datablob, options);
+	if (rc < 0)
+		goto out;
+	dump_options(options);
+
+	input_len = p->key_len;
+	input_buf = kmalloc(ALIGN(input_len, 4096), GFP_KERNEL);
+	if (!input_buf) {
+		pr_err("Input buffer allocation failed. Returning -ENOMEM.");
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	memcpy(input_buf, p->key, p->key_len);
+
+	pkwm = options->private;
+
+	rc = plpks_wrap_object(&input_buf, input_len, pkwm->wrap_flags,
+			       &output_buf, &output_len);
+	if (!rc) {
+		memcpy(p->blob, output_buf, output_len);
+		p->blob_len = output_len;
+		dump_payload(p);
+	} else {
+		pr_err("Wrapping of payload key failed: %d\n", rc);
+	}
+
+	kfree(input_buf);
+	kfree(output_buf);
+
+out:
+	kfree_sensitive(options->private);
+	kfree_sensitive(options);
+	return rc;
+}
+
+static int trusted_pkwm_unseal(struct trusted_key_payload *p, char *datablob)
+{
+	u8 *input_buf, *output_buf;
+	u32 input_len, output_len;
+	int rc;
+
+	input_len = p->blob_len;
+	input_buf = kmalloc(ALIGN(input_len, 4096), GFP_KERNEL);
+	if (!input_buf) {
+		pr_err("Input buffer allocation failed. Returning -ENOMEM.");
+		return -ENOMEM;
+	}
+
+	memcpy(input_buf, p->blob, p->blob_len);
+
+	rc = plpks_unwrap_object(&input_buf, input_len, &output_buf,
+				 &output_len);
+	if (!rc) {
+		memcpy(p->key, output_buf, output_len);
+		p->key_len = output_len;
+		dump_payload(p);
+	} else {
+		pr_err("Unwrapping of payload failed: %d\n", rc);
+	}
+
+	kfree(input_buf);
+	kfree(output_buf);
+
+	return rc;
+}
+
+static int trusted_pkwm_init(void)
+{
+	int ret;
+
+	if (!plpks_wrapping_is_supported()) {
+		pr_err("H_PKS_WRAP_OBJECT interface not supported\n");
+		return -ENODEV;
+	}
+
+	ret = plpks_gen_wrapping_key();
+	if (ret) {
+		pr_err("Failed to generate default wrapping key\n");
+		return -EINVAL;
+	}
+
+	return register_key_type(&key_type_trusted);
+}
+
+static void trusted_pkwm_exit(void)
+{
+	unregister_key_type(&key_type_trusted);
+}
+
+struct trusted_key_ops pkwm_trusted_key_ops = {
+	.migratable = 0, /* non-migratable */
+	.init = trusted_pkwm_init,
+	.seal = trusted_pkwm_seal,
+	.unseal = trusted_pkwm_unseal,
+	.exit = trusted_pkwm_exit,
+};
-- 
2.47.3


^ permalink raw reply related

* [PATCH v5 3/6] pseries/plpks: expose PowerVM wrapping features via the sysfs
From: Srish Srinivasan @ 2026-01-27 14:52 UTC (permalink / raw)
  To: linux-integrity, keyrings, linuxppc-dev
  Cc: maddy, mpe, npiggin, christophe.leroy, James.Bottomley, jarkko,
	zohar, nayna, rnsastry, linux-kernel, linux-security-module,
	ssrish
In-Reply-To: <20260127145228.48320-1-ssrish@linux.ibm.com>

Starting with Power11, PowerVM supports a new feature called "Key Wrapping"
that protects user secrets by wrapping them using a hypervisor generated
wrapping key. The status of this feature can be read by the
H_PKS_GET_CONFIG HCALL.

Expose the Power LPAR Platform KeyStore (PLPKS) wrapping features config
via the sysfs file /sys/firmware/plpks/config/wrapping_features.

Signed-off-by: Srish Srinivasan <ssrish@linux.ibm.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
---
 .../ABI/testing/sysfs-firmware-plpks          |  8 ++++++++
 arch/powerpc/include/asm/hvcall.h             |  4 +++-
 arch/powerpc/include/asm/plpks.h              |  3 +++
 arch/powerpc/platforms/pseries/plpks-sysfs.c  |  2 ++
 arch/powerpc/platforms/pseries/plpks.c        | 20 +++++++++++++++++++
 5 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-firmware-plpks b/Documentation/ABI/testing/sysfs-firmware-plpks
index af0353f34115..cba061e4eee2 100644
--- a/Documentation/ABI/testing/sysfs-firmware-plpks
+++ b/Documentation/ABI/testing/sysfs-firmware-plpks
@@ -48,3 +48,11 @@ Description:	Bitmask of flags indicating which algorithms the hypervisor
 		supports for signed update of objects, represented as a 16 byte
 		hexadecimal ASCII string. Consult the hypervisor documentation
 		for what these flags mean.
+
+What:		/sys/firmware/plpks/config/wrapping_features
+Date:		November 2025
+Contact:	Srish Srinivasan <ssrish@linux.ibm.com>
+Description:	Bitmask of the wrapping features indicating the wrapping
+		algorithms that are supported for the H_PKS_WRAP_OBJECT requests
+		, represented as a 8 byte hexadecimal ASCII string. Consult the
+		hypervisor documentation for what these flags mean.
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index 9aef16149d92..dff90a7d7f70 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -360,7 +360,9 @@
 #define H_GUEST_RUN_VCPU	0x480
 #define H_GUEST_COPY_MEMORY	0x484
 #define H_GUEST_DELETE		0x488
-#define MAX_HCALL_OPCODE	H_GUEST_DELETE
+#define H_PKS_WRAP_OBJECT	0x490
+#define H_PKS_UNWRAP_OBJECT	0x494
+#define MAX_HCALL_OPCODE	H_PKS_UNWRAP_OBJECT
 
 /* Scope args for H_SCM_UNBIND_ALL */
 #define H_UNBIND_SCOPE_ALL (0x1)
diff --git a/arch/powerpc/include/asm/plpks.h b/arch/powerpc/include/asm/plpks.h
index 8829a13bfda0..8f034588fdf7 100644
--- a/arch/powerpc/include/asm/plpks.h
+++ b/arch/powerpc/include/asm/plpks.h
@@ -23,6 +23,7 @@
 #define PLPKS_IMMUTABLE		PPC_BIT32(5) // Once written, object cannot be removed
 #define PLPKS_TRANSIENT		PPC_BIT32(6) // Object does not persist through reboot
 #define PLPKS_SIGNEDUPDATE	PPC_BIT32(7) // Object can only be modified by signed updates
+#define PLPKS_WRAPPINGKEY	PPC_BIT32(8) // Object contains a wrapping key
 #define PLPKS_HVPROVISIONED	PPC_BIT32(28) // Hypervisor has provisioned this object
 
 // Signature algorithm flags from signed_update_algorithms
@@ -103,6 +104,8 @@ u32 plpks_get_maxlargeobjectsize(void);
 
 u64 plpks_get_signedupdatealgorithms(void);
 
+u64 plpks_get_wrappingfeatures(void);
+
 u16 plpks_get_passwordlen(void);
 
 void plpks_early_init_devtree(void);
diff --git a/arch/powerpc/platforms/pseries/plpks-sysfs.c b/arch/powerpc/platforms/pseries/plpks-sysfs.c
index 01d526185783..c2ebcbb41ae3 100644
--- a/arch/powerpc/platforms/pseries/plpks-sysfs.c
+++ b/arch/powerpc/platforms/pseries/plpks-sysfs.c
@@ -30,6 +30,7 @@ PLPKS_CONFIG_ATTR(used_space, "%u\n", plpks_get_usedspace);
 PLPKS_CONFIG_ATTR(supported_policies, "%08x\n", plpks_get_supportedpolicies);
 PLPKS_CONFIG_ATTR(signed_update_algorithms, "%016llx\n",
 		  plpks_get_signedupdatealgorithms);
+PLPKS_CONFIG_ATTR(wrapping_features, "%016llx\n", plpks_get_wrappingfeatures);
 
 static const struct attribute *config_attrs[] = {
 	&attr_version.attr,
@@ -38,6 +39,7 @@ static const struct attribute *config_attrs[] = {
 	&attr_used_space.attr,
 	&attr_supported_policies.attr,
 	&attr_signed_update_algorithms.attr,
+	&attr_wrapping_features.attr,
 	NULL,
 };
 
diff --git a/arch/powerpc/platforms/pseries/plpks.c b/arch/powerpc/platforms/pseries/plpks.c
index 03722fabf9c3..4a08f51537c8 100644
--- a/arch/powerpc/platforms/pseries/plpks.c
+++ b/arch/powerpc/platforms/pseries/plpks.c
@@ -38,6 +38,7 @@ static u32 usedspace;
 static u32 supportedpolicies;
 static u32 maxlargeobjectsize;
 static u64 signedupdatealgorithms;
+static u64 wrappingfeatures;
 
 struct plpks_auth {
 	u8 version;
@@ -248,6 +249,7 @@ static int _plpks_get_config(void)
 		__be32 supportedpolicies;
 		__be32 maxlargeobjectsize;
 		__be64 signedupdatealgorithms;
+		__be64 wrappingfeatures;
 		u8 rsvd1[476];
 	} __packed * config;
 	size_t size;
@@ -280,6 +282,7 @@ static int _plpks_get_config(void)
 	supportedpolicies = be32_to_cpu(config->supportedpolicies);
 	maxlargeobjectsize = be32_to_cpu(config->maxlargeobjectsize);
 	signedupdatealgorithms = be64_to_cpu(config->signedupdatealgorithms);
+	wrappingfeatures = be64_to_cpu(config->wrappingfeatures);
 
 	// Validate that the numbers we get back match the requirements of the spec
 	if (maxpwsize < 32) {
@@ -472,6 +475,23 @@ u64 plpks_get_signedupdatealgorithms(void)
 	return signedupdatealgorithms;
 }
 
+/**
+ * plpks_get_wrappingfeatures() - Returns a bitmask of the wrapping features
+ * supported by the hypervisor.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads a bitmask of the wrapping features supported by the hypervisor into the
+ * file local static wrappingfeatures variable. This is valid only when the
+ * PLPKS config structure version >= 3.
+ *
+ * Return:
+ *	bitmask of the wrapping features supported by the hypervisor
+ */
+u64 plpks_get_wrappingfeatures(void)
+{
+	return wrappingfeatures;
+}
+
 /**
  * plpks_get_passwordlen() - Get the length of the PLPKS password in bytes.
  *
-- 
2.47.3


^ permalink raw reply related

* [PATCH v5 2/6] powerpc/pseries: move the PLPKS config inside its own sysfs directory
From: Srish Srinivasan @ 2026-01-27 14:52 UTC (permalink / raw)
  To: linux-integrity, keyrings, linuxppc-dev
  Cc: maddy, mpe, npiggin, christophe.leroy, James.Bottomley, jarkko,
	zohar, nayna, rnsastry, linux-kernel, linux-security-module,
	ssrish
In-Reply-To: <20260127145228.48320-1-ssrish@linux.ibm.com>

The /sys/firmware/secvar/config directory represents Power LPAR Platform
KeyStore (PLPKS) configuration properties such as max_object_size, signed_
update_algorithms, supported_policies, total_size, used_space, and version.
These attributes describe the PLPKS, and not the secure boot variables
(secvars).

Create /sys/firmware/plpks directory and move the PLPKS config inside this
directory. For backwards compatibility, create a soft link from the secvar
sysfs directory to this config and emit a warning stating that the older
sysfs path has been deprecated. Separate out the plpks specific
documentation from secvar.

Signed-off-by: Srish Srinivasan <ssrish@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
---
 .../ABI/testing/sysfs-firmware-plpks          | 50 ++++++++++
 Documentation/ABI/testing/sysfs-secvar        | 65 -------------
 arch/powerpc/include/asm/plpks.h              |  5 +
 arch/powerpc/include/asm/secvar.h             |  1 -
 arch/powerpc/kernel/secvar-sysfs.c            | 21 ++---
 arch/powerpc/platforms/pseries/Makefile       |  2 +-
 arch/powerpc/platforms/pseries/plpks-secvar.c | 29 ------
 arch/powerpc/platforms/pseries/plpks-sysfs.c  | 94 +++++++++++++++++++
 8 files changed, 156 insertions(+), 111 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-firmware-plpks
 create mode 100644 arch/powerpc/platforms/pseries/plpks-sysfs.c

diff --git a/Documentation/ABI/testing/sysfs-firmware-plpks b/Documentation/ABI/testing/sysfs-firmware-plpks
new file mode 100644
index 000000000000..af0353f34115
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-firmware-plpks
@@ -0,0 +1,50 @@
+What:		/sys/firmware/plpks/config
+Date:		February 2023
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	This optional directory contains read-only config attributes as
+		defined by the PLPKS implementation. All data is in ASCII
+		format.
+
+What:		/sys/firmware/plpks/config/version
+Date:		February 2023
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	Config version as reported by the hypervisor in ASCII decimal
+		format.
+
+What:		/sys/firmware/plpks/config/max_object_size
+Date:		February 2023
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	Maximum allowed size of	objects in the keystore in bytes,
+		represented in ASCII decimal format.
+
+		This is not necessarily the same as the max size that can be
+		written to an update file as writes can contain more than
+		object data, you should use the size of the update file for
+		that purpose.
+
+What:		/sys/firmware/plpks/config/total_size
+Date:		February 2023
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	Total size of the PLPKS in bytes, represented in ASCII decimal
+		format.
+
+What:		/sys/firmware/plpks/config/used_space
+Date:		February 2023
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	Current space consumed by the key store, in bytes, represented
+		in ASCII decimal format.
+
+What:		/sys/firmware/plpks/config/supported_policies
+Date:		February 2023
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	Bitmask of supported policy flags by the hypervisor, represented
+		as an 8 byte hexadecimal ASCII string. Consult the hypervisor
+		documentation for what these flags are.
+
+What:		/sys/firmware/plpks/config/signed_update_algorithms
+Date:		February 2023
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	Bitmask of flags indicating which algorithms the hypervisor
+		supports for signed update of objects, represented as a 16 byte
+		hexadecimal ASCII string. Consult the hypervisor documentation
+		for what these flags mean.
diff --git a/Documentation/ABI/testing/sysfs-secvar b/Documentation/ABI/testing/sysfs-secvar
index 1016967a730f..c52a5fd15709 100644
--- a/Documentation/ABI/testing/sysfs-secvar
+++ b/Documentation/ABI/testing/sysfs-secvar
@@ -63,68 +63,3 @@ Contact:	Nayna Jain <nayna@linux.ibm.com>
 Description:	A write-only file that is used to submit the new value for the
 		variable. The size of the file represents the maximum size of
 		the variable data that can be written.
-
-What:		/sys/firmware/secvar/config
-Date:		February 2023
-Contact:	Nayna Jain <nayna@linux.ibm.com>
-Description:	This optional directory contains read-only config attributes as
-		defined by the secure variable implementation.  All data is in
-		ASCII format. The directory is only created if the backing
-		implementation provides variables to populate it, which at
-		present is only PLPKS on the pseries platform.
-
-What:		/sys/firmware/secvar/config/version
-Date:		February 2023
-Contact:	Nayna Jain <nayna@linux.ibm.com>
-Description:	Config version as reported by the hypervisor in ASCII decimal
-		format.
-
-		Currently only provided by PLPKS on the pseries platform.
-
-What:		/sys/firmware/secvar/config/max_object_size
-Date:		February 2023
-Contact:	Nayna Jain <nayna@linux.ibm.com>
-Description:	Maximum allowed size of	objects in the keystore in bytes,
-		represented in ASCII decimal format.
-
-		This is not necessarily the same as the max size that can be
-		written to an update file as writes can contain more than
-		object data, you should use the size of the update file for
-		that purpose.
-
-		Currently only provided by PLPKS on the pseries platform.
-
-What:		/sys/firmware/secvar/config/total_size
-Date:		February 2023
-Contact:	Nayna Jain <nayna@linux.ibm.com>
-Description:	Total size of the PLPKS in bytes, represented in ASCII decimal
-		format.
-
-		Currently only provided by PLPKS on the pseries platform.
-
-What:		/sys/firmware/secvar/config/used_space
-Date:		February 2023
-Contact:	Nayna Jain <nayna@linux.ibm.com>
-Description:	Current space consumed by the key store, in bytes, represented
-		in ASCII decimal format.
-
-		Currently only provided by PLPKS on the pseries platform.
-
-What:		/sys/firmware/secvar/config/supported_policies
-Date:		February 2023
-Contact:	Nayna Jain <nayna@linux.ibm.com>
-Description:	Bitmask of supported policy flags by the hypervisor,
-		represented as an 8 byte hexadecimal ASCII string. Consult the
-		hypervisor documentation for what these flags are.
-
-		Currently only provided by PLPKS on the pseries platform.
-
-What:		/sys/firmware/secvar/config/signed_update_algorithms
-Date:		February 2023
-Contact:	Nayna Jain <nayna@linux.ibm.com>
-Description:	Bitmask of flags indicating which algorithms the hypervisor
-		supports for signed update of objects, represented as a 16 byte
-		hexadecimal ASCII string. Consult the hypervisor documentation
-		for what these flags mean.
-
-		Currently only provided by PLPKS on the pseries platform.
diff --git a/arch/powerpc/include/asm/plpks.h b/arch/powerpc/include/asm/plpks.h
index f303922bf622..8829a13bfda0 100644
--- a/arch/powerpc/include/asm/plpks.h
+++ b/arch/powerpc/include/asm/plpks.h
@@ -13,6 +13,7 @@
 
 #include <linux/types.h>
 #include <linux/list.h>
+#include <linux/kobject.h>
 
 // Object policy flags from supported_policies
 #define PLPKS_OSSECBOOTAUDIT	PPC_BIT32(1) // OS secure boot must be audit/enforce
@@ -107,11 +108,15 @@ u16 plpks_get_passwordlen(void);
 void plpks_early_init_devtree(void);
 
 int plpks_populate_fdt(void *fdt);
+
+int plpks_config_create_softlink(struct kobject *from);
 #else // CONFIG_PSERIES_PLPKS
 static inline bool plpks_is_available(void) { return false; }
 static inline u16 plpks_get_passwordlen(void) { BUILD_BUG(); }
 static inline void plpks_early_init_devtree(void) { }
 static inline int plpks_populate_fdt(void *fdt) { BUILD_BUG(); }
+static inline int plpks_config_create_softlink(struct kobject *from)
+						{ return 0; }
 #endif // CONFIG_PSERIES_PLPKS
 
 #endif // _ASM_POWERPC_PLPKS_H
diff --git a/arch/powerpc/include/asm/secvar.h b/arch/powerpc/include/asm/secvar.h
index 4828e0ab7e3c..fd5006307f2a 100644
--- a/arch/powerpc/include/asm/secvar.h
+++ b/arch/powerpc/include/asm/secvar.h
@@ -20,7 +20,6 @@ struct secvar_operations {
 	int (*set)(const char *key, u64 key_len, u8 *data, u64 data_size);
 	ssize_t (*format)(char *buf, size_t bufsize);
 	int (*max_size)(u64 *max_size);
-	const struct attribute **config_attrs;
 
 	// NULL-terminated array of fixed variable names
 	// Only used if get_next() isn't provided
diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c
index ec900bce0257..4111b21962eb 100644
--- a/arch/powerpc/kernel/secvar-sysfs.c
+++ b/arch/powerpc/kernel/secvar-sysfs.c
@@ -12,6 +12,7 @@
 #include <linux/string.h>
 #include <linux/of.h>
 #include <asm/secvar.h>
+#include <asm/plpks.h>
 
 #define NAME_MAX_SIZE	   1024
 
@@ -145,19 +146,6 @@ static __init int update_kobj_size(void)
 	return 0;
 }
 
-static __init int secvar_sysfs_config(struct kobject *kobj)
-{
-	struct attribute_group config_group = {
-		.name = "config",
-		.attrs = (struct attribute **)secvar_ops->config_attrs,
-	};
-
-	if (secvar_ops->config_attrs)
-		return sysfs_create_group(kobj, &config_group);
-
-	return 0;
-}
-
 static __init int add_var(const char *name)
 {
 	struct kobject *kobj;
@@ -260,12 +248,15 @@ static __init int secvar_sysfs_init(void)
 		goto err;
 	}
 
-	rc = secvar_sysfs_config(secvar_kobj);
+	rc = plpks_config_create_softlink(secvar_kobj);
 	if (rc) {
-		pr_err("Failed to create config directory\n");
+		pr_err("Failed to create softlink to PLPKS config directory");
 		goto err;
 	}
 
+	pr_info("/sys/firmware/secvar/config is now deprecated.\n");
+	pr_info("Will be removed in future versions.\n");
+
 	if (secvar_ops->get_next)
 		rc = secvar_sysfs_load();
 	else
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 931ebaa474c8..3ced289a675b 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -30,7 +30,7 @@ obj-$(CONFIG_PAPR_SCM)		+= papr_scm.o
 obj-$(CONFIG_PPC_SPLPAR)	+= vphn.o
 obj-$(CONFIG_PPC_SVM)		+= svm.o
 obj-$(CONFIG_FA_DUMP)		+= rtas-fadump.o
-obj-$(CONFIG_PSERIES_PLPKS)	+= plpks.o
+obj-$(CONFIG_PSERIES_PLPKS)	+= plpks.o plpks-sysfs.o
 obj-$(CONFIG_PPC_SECURE_BOOT)	+= plpks-secvar.o
 obj-$(CONFIG_PSERIES_PLPKS_SED)	+= plpks_sed_ops.o
 obj-$(CONFIG_SUSPEND)		+= suspend.o
diff --git a/arch/powerpc/platforms/pseries/plpks-secvar.c b/arch/powerpc/platforms/pseries/plpks-secvar.c
index f9e9cc40c9d0..a50ff6943d80 100644
--- a/arch/powerpc/platforms/pseries/plpks-secvar.c
+++ b/arch/powerpc/platforms/pseries/plpks-secvar.c
@@ -20,33 +20,6 @@
 #include <asm/secvar.h>
 #include <asm/plpks.h>
 
-// Config attributes for sysfs
-#define PLPKS_CONFIG_ATTR(name, fmt, func)			\
-	static ssize_t name##_show(struct kobject *kobj,	\
-				   struct kobj_attribute *attr,	\
-				   char *buf)			\
-	{							\
-		return sysfs_emit(buf, fmt, func());		\
-	}							\
-	static struct kobj_attribute attr_##name = __ATTR_RO(name)
-
-PLPKS_CONFIG_ATTR(version, "%u\n", plpks_get_version);
-PLPKS_CONFIG_ATTR(max_object_size, "%u\n", plpks_get_maxobjectsize);
-PLPKS_CONFIG_ATTR(total_size, "%u\n", plpks_get_totalsize);
-PLPKS_CONFIG_ATTR(used_space, "%u\n", plpks_get_usedspace);
-PLPKS_CONFIG_ATTR(supported_policies, "%08x\n", plpks_get_supportedpolicies);
-PLPKS_CONFIG_ATTR(signed_update_algorithms, "%016llx\n", plpks_get_signedupdatealgorithms);
-
-static const struct attribute *config_attrs[] = {
-	&attr_version.attr,
-	&attr_max_object_size.attr,
-	&attr_total_size.attr,
-	&attr_used_space.attr,
-	&attr_supported_policies.attr,
-	&attr_signed_update_algorithms.attr,
-	NULL,
-};
-
 static u32 get_policy(const char *name)
 {
 	if ((strcmp(name, "db") == 0) ||
@@ -225,7 +198,6 @@ static const struct secvar_operations plpks_secvar_ops_static = {
 	.set = plpks_set_variable,
 	.format = plpks_secvar_format,
 	.max_size = plpks_max_size,
-	.config_attrs = config_attrs,
 	.var_names = plpks_var_names_static,
 };
 
@@ -234,7 +206,6 @@ static const struct secvar_operations plpks_secvar_ops_dynamic = {
 	.set = plpks_set_variable,
 	.format = plpks_secvar_format,
 	.max_size = plpks_max_size,
-	.config_attrs = config_attrs,
 	.var_names = plpks_var_names_dynamic,
 };
 
diff --git a/arch/powerpc/platforms/pseries/plpks-sysfs.c b/arch/powerpc/platforms/pseries/plpks-sysfs.c
new file mode 100644
index 000000000000..01d526185783
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/plpks-sysfs.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 IBM Corporation, Srish Srinivasan <ssrish@linux.ibm.com>
+ *
+ * This code exposes PLPKS config to user via sysfs
+ */
+
+#define pr_fmt(fmt) "plpks-sysfs: "fmt
+
+#include <linux/init.h>
+#include <linux/printk.h>
+#include <linux/types.h>
+#include <asm/machdep.h>
+#include <asm/plpks.h>
+
+/* config attributes for sysfs */
+#define PLPKS_CONFIG_ATTR(name, fmt, func)			\
+	static ssize_t name##_show(struct kobject *kobj,	\
+				   struct kobj_attribute *attr,	\
+				   char *buf)			\
+	{							\
+		return sysfs_emit(buf, fmt, func());		\
+	}							\
+	static struct kobj_attribute attr_##name = __ATTR_RO(name)
+
+PLPKS_CONFIG_ATTR(version, "%u\n", plpks_get_version);
+PLPKS_CONFIG_ATTR(max_object_size, "%u\n", plpks_get_maxobjectsize);
+PLPKS_CONFIG_ATTR(total_size, "%u\n", plpks_get_totalsize);
+PLPKS_CONFIG_ATTR(used_space, "%u\n", plpks_get_usedspace);
+PLPKS_CONFIG_ATTR(supported_policies, "%08x\n", plpks_get_supportedpolicies);
+PLPKS_CONFIG_ATTR(signed_update_algorithms, "%016llx\n",
+		  plpks_get_signedupdatealgorithms);
+
+static const struct attribute *config_attrs[] = {
+	&attr_version.attr,
+	&attr_max_object_size.attr,
+	&attr_total_size.attr,
+	&attr_used_space.attr,
+	&attr_supported_policies.attr,
+	&attr_signed_update_algorithms.attr,
+	NULL,
+};
+
+static struct kobject *plpks_kobj, *plpks_config_kobj;
+
+int plpks_config_create_softlink(struct kobject *from)
+{
+	if (!plpks_config_kobj)
+		return -EINVAL;
+	return sysfs_create_link(from, plpks_config_kobj, "config");
+}
+
+static __init int plpks_sysfs_config(struct kobject *kobj)
+{
+	struct attribute_group config_group = {
+		.name = NULL,
+		.attrs = (struct attribute **)config_attrs,
+	};
+
+	return sysfs_create_group(kobj, &config_group);
+}
+
+static __init int plpks_sysfs_init(void)
+{
+	int rc;
+
+	if (!plpks_is_available())
+		return -ENODEV;
+
+	plpks_kobj = kobject_create_and_add("plpks", firmware_kobj);
+	if (!plpks_kobj) {
+		pr_err("Failed to create plpks kobj\n");
+		return -ENOMEM;
+	}
+
+	plpks_config_kobj = kobject_create_and_add("config", plpks_kobj);
+	if (!plpks_config_kobj) {
+		pr_err("Failed to create plpks config kobj\n");
+		kobject_put(plpks_kobj);
+		return -ENOMEM;
+	}
+
+	rc = plpks_sysfs_config(plpks_config_kobj);
+	if (rc) {
+		pr_err("Failed to create attribute group for plpks config\n");
+		kobject_put(plpks_config_kobj);
+		kobject_put(plpks_kobj);
+		return rc;
+	}
+
+	return 0;
+}
+
+machine_subsys_initcall(pseries, plpks_sysfs_init);
-- 
2.47.3


^ permalink raw reply related

* [PATCH v5 1/6] pseries/plpks: fix kernel-doc comment inconsistencies
From: Srish Srinivasan @ 2026-01-27 14:52 UTC (permalink / raw)
  To: linux-integrity, keyrings, linuxppc-dev
  Cc: maddy, mpe, npiggin, christophe.leroy, James.Bottomley, jarkko,
	zohar, nayna, rnsastry, linux-kernel, linux-security-module,
	ssrish
In-Reply-To: <20260127145228.48320-1-ssrish@linux.ibm.com>

Fix issues with comments for all the applicable functions to be
consistent with kernel-doc format. Move them before the function
definition as opposed to the function prototype.

Signed-off-by: Srish Srinivasan <ssrish@linux.ibm.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
---
 arch/powerpc/include/asm/plpks.h       |  77 ------
 arch/powerpc/platforms/pseries/plpks.c | 328 ++++++++++++++++++++++++-
 2 files changed, 318 insertions(+), 87 deletions(-)

diff --git a/arch/powerpc/include/asm/plpks.h b/arch/powerpc/include/asm/plpks.h
index 7a84069759b0..f303922bf622 100644
--- a/arch/powerpc/include/asm/plpks.h
+++ b/arch/powerpc/include/asm/plpks.h
@@ -67,122 +67,45 @@ struct plpks_var_name_list {
 	struct plpks_var_name varlist[];
 };
 
-/**
- * Updates the authenticated variable. It expects NULL as the component.
- */
 int plpks_signed_update_var(struct plpks_var *var, u64 flags);
 
-/**
- * Writes the specified var and its data to PKS.
- * Any caller of PKS driver should present a valid component type for
- * their variable.
- */
 int plpks_write_var(struct plpks_var var);
 
-/**
- * Removes the specified var and its data from PKS.
- */
 int plpks_remove_var(char *component, u8 varos,
 		     struct plpks_var_name vname);
 
-/**
- * Returns the data for the specified os variable.
- *
- * Caller must allocate a buffer in var->data with length in var->datalen.
- * If no buffer is provided, var->datalen will be populated with the object's
- * size.
- */
 int plpks_read_os_var(struct plpks_var *var);
 
-/**
- * Returns the data for the specified firmware variable.
- *
- * Caller must allocate a buffer in var->data with length in var->datalen.
- * If no buffer is provided, var->datalen will be populated with the object's
- * size.
- */
 int plpks_read_fw_var(struct plpks_var *var);
 
-/**
- * Returns the data for the specified bootloader variable.
- *
- * Caller must allocate a buffer in var->data with length in var->datalen.
- * If no buffer is provided, var->datalen will be populated with the object's
- * size.
- */
 int plpks_read_bootloader_var(struct plpks_var *var);
 
-/**
- * Returns if PKS is available on this LPAR.
- */
 bool plpks_is_available(void);
 
-/**
- * Returns version of the Platform KeyStore.
- */
 u8 plpks_get_version(void);
 
-/**
- * Returns hypervisor storage overhead per object, not including the size of
- * the object or label. Only valid for config version >= 2
- */
 u16 plpks_get_objoverhead(void);
 
-/**
- * Returns maximum password size. Must be >= 32 bytes
- */
 u16 plpks_get_maxpwsize(void);
 
-/**
- * Returns maximum object size supported by Platform KeyStore.
- */
 u16 plpks_get_maxobjectsize(void);
 
-/**
- * Returns maximum object label size supported by Platform KeyStore.
- */
 u16 plpks_get_maxobjectlabelsize(void);
 
-/**
- * Returns total size of the configured Platform KeyStore.
- */
 u32 plpks_get_totalsize(void);
 
-/**
- * Returns used space from the total size of the Platform KeyStore.
- */
 u32 plpks_get_usedspace(void);
 
-/**
- * Returns bitmask of policies supported by the hypervisor.
- */
 u32 plpks_get_supportedpolicies(void);
 
-/**
- * Returns maximum byte size of a single object supported by the hypervisor.
- * Only valid for config version >= 3
- */
 u32 plpks_get_maxlargeobjectsize(void);
 
-/**
- * Returns bitmask of signature algorithms supported for signed updates.
- * Only valid for config version >= 3
- */
 u64 plpks_get_signedupdatealgorithms(void);
 
-/**
- * Returns the length of the PLPKS password in bytes.
- */
 u16 plpks_get_passwordlen(void);
 
-/**
- * Called in early init to retrieve and clear the PLPKS password from the DT.
- */
 void plpks_early_init_devtree(void);
 
-/**
- * Populates the FDT with the PLPKS password to prepare for kexec.
- */
 int plpks_populate_fdt(void *fdt);
 #else // CONFIG_PSERIES_PLPKS
 static inline bool plpks_is_available(void) { return false; }
diff --git a/arch/powerpc/platforms/pseries/plpks.c b/arch/powerpc/platforms/pseries/plpks.c
index b1667ed05f98..03722fabf9c3 100644
--- a/arch/powerpc/platforms/pseries/plpks.c
+++ b/arch/powerpc/platforms/pseries/plpks.c
@@ -312,40 +312,107 @@ static int _plpks_get_config(void)
 	return rc;
 }
 
+/**
+ * plpks_get_version() - Get the version of the PLPKS config structure.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads the PLPKS config structure version and saves it in a file local static
+ * version variable.
+ *
+ * Returns: On success the saved PLPKS config structure version is returned, 0
+ * if not.
+ */
 u8 plpks_get_version(void)
 {
 	return version;
 }
 
+/**
+ * plpks_get_objoverhead() - Get the hypervisor storage overhead per object.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads the per object hypervisor storage overhead in bytes into the local
+ * static objoverhead variable, excluding the size of the object or the label.
+ * This value can be treated as valid only when the PLPKS config structure
+ * version >= 2.
+ *
+ * Returns: If PLPKS config structure version >= 2 then the storage overhead is
+ * returned, 0 otherwise.
+ */
 u16 plpks_get_objoverhead(void)
 {
 	return objoverhead;
 }
 
+/**
+ * plpks_get_maxpwsize() - Get the maximum password size.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads the maximum password size and checks if it is 32 bytes at the least
+ * before storing it in the local static maxpwsize variable.
+ *
+ * Returns: On success the maximum password size is returned, 0 if not.
+ */
 u16 plpks_get_maxpwsize(void)
 {
 	return maxpwsize;
 }
 
+/**
+ * plpks_get_maxobjectsize() - Get the maximum object size supported by the
+ * PLPKS.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads the maximum object size into the file local static maxobjsize variable.
+ *
+ * Returns: On success the maximum object size is returned, 0 if not.
+ */
 u16 plpks_get_maxobjectsize(void)
 {
 	return maxobjsize;
 }
 
+/**
+ * plpks_get_maxobjectlabelsize() - Get the maximum object label size supported
+ * by the PLPKS.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads the maximum object label size into the local static maxobjlabelsize
+ * variable.
+ *
+ * Returns: On success the maximum object label size is returned, 0 if not.
+ */
 u16 plpks_get_maxobjectlabelsize(void)
 {
 	return maxobjlabelsize;
 }
 
+/**
+ * plpks_get_totalsize() - Get the total size of the PLPKS that is configured.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads the total size of the PLPKS that is configured for the LPAR into the
+ * file local static totalsize variable.
+ *
+ * Returns: On success the total size of the PLPKS configured is returned, 0 if
+ * not.
+ */
 u32 plpks_get_totalsize(void)
 {
 	return totalsize;
 }
 
+/**
+ * plpks_get_usedspace() - Get the used space from the total size of the PLPKS.
+ *
+ * Invoke the H_PKS_GET_CONFIG HCALL to refresh the latest value for the used
+ * space as this keeps changing with the creation and removal of objects in the
+ * PLPKS.
+ *
+ * Returns: On success the used space is returned, 0 if not.
+ */
 u32 plpks_get_usedspace(void)
 {
-	// Unlike other config values, usedspace regularly changes as objects
-	// are updated, so we need to refresh.
 	int rc = _plpks_get_config();
 	if (rc) {
 		pr_err("Couldn't get config, rc: %d\n", rc);
@@ -354,26 +421,84 @@ u32 plpks_get_usedspace(void)
 	return usedspace;
 }
 
+/**
+ * plpks_get_supportedpolicies() - Get a bitmask of the policies supported by
+ * the hypervisor.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads a bitmask of the policies supported by the hypervisor into the file
+ * local static supportedpolicies variable.
+ *
+ * Returns: On success the bitmask of the policies supported by the hypervisor
+ * are returned, 0 if not.
+ */
 u32 plpks_get_supportedpolicies(void)
 {
 	return supportedpolicies;
 }
 
+/**
+ * plpks_get_maxlargeobjectsize() - Get the maximum object size supported for
+ * PLPKS config structure version >= 3
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads the maximum object size into the local static maxlargeobjectsize
+ * variable for PLPKS config structure version >= 3. This was introduced
+ * starting with PLPKS config structure version 3 to allow for objects of
+ * size >= 64K.
+ *
+ * Returns: If PLPKS config structure version >= 3 then the new maximum object
+ * size is returned, 0 if not.
+ */
 u32 plpks_get_maxlargeobjectsize(void)
 {
 	return maxlargeobjectsize;
 }
 
+/**
+ * plpks_get_signedupdatealgorithms() - Get a bitmask of the signature
+ * algorithms supported for signed updates.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads a bitmask of the signature algorithms supported for signed updates into
+ * the file local static signedupdatealgorithms variable. This is valid only
+ * when the PLPKS config structure version >= 3.
+ *
+ * Returns: On success the bitmask of the signature algorithms supported for
+ * signed updates is returned, 0 if not.
+ */
 u64 plpks_get_signedupdatealgorithms(void)
 {
 	return signedupdatealgorithms;
 }
 
+/**
+ * plpks_get_passwordlen() - Get the length of the PLPKS password in bytes.
+ *
+ * The H_PKS_GEN_PASSWORD HCALL makes the hypervisor generate a random password
+ * for the specified consumer, apply that password to the PLPKS and return it to
+ * the caller. In this process, the password length for the OS consumer is
+ * stored in the local static ospasswordlength variable.
+ *
+ * Returns: On success the password length for the OS consumer in bytes is
+ * returned, 0 if not.
+ */
 u16 plpks_get_passwordlen(void)
 {
 	return ospasswordlength;
 }
 
+/**
+ * plpks_is_available() - Get the PLPKS availability status for the LPAR.
+ *
+ * The availability of PLPKS is inferred based upon the successful execution of
+ * the H_PKS_GET_CONFIG HCALL provided the firmware supports this feature. The
+ * H_PKS_GET_CONFIG HCALL reads the configuration and status information related
+ * to the PLPKS. The configuration structure provides a version number to inform
+ * the caller of the supported features.
+ *
+ * Returns: true is returned if PLPKS is available, false if not.
+ */
 bool plpks_is_available(void)
 {
 	int rc;
@@ -425,6 +550,35 @@ static int plpks_confirm_object_flushed(struct label *label,
 	return pseries_status_to_err(rc);
 }
 
+/**
+ * plpks_signed_update_var() - Update the specified authenticated variable.
+ * @var: authenticated variable to be updated
+ * @flags: signed update request operation flags
+ *
+ * The H_PKS_SIGNED_UPDATE HCALL performs a signed update to an object in the
+ * PLPKS. The object must have the signed update policy flag set.
+ *
+ * Possible reasons for the returned errno values:
+ *
+ * -ENXIO	if PLPKS is not supported
+ * -EIO		if PLPKS access is blocked due to the LPAR's state
+ *		if PLPKS modification is blocked due to the LPAR's state
+ *		if an error occurred while processing the request
+ * -EINVAL	if invalid authorization parameter
+ *		if invalid object label parameter
+ *		if invalid object label len parameter
+ *		if invalid or unsupported policy declaration
+ *		if invalid signed update flags
+ *		if invalid input data parameter
+ *		if invalid input data len parameter
+ *		if invalid continue token parameter
+ * -EPERM	if access is denied
+ * -ENOMEM	if there is inadequate memory to perform the operation
+ * -EBUSY	if unable to handle the request or long running operation
+ *		initiated, retry later
+ *
+ * Returns: On success 0 is returned, a negative errno if not.
+ */
 int plpks_signed_update_var(struct plpks_var *var, u64 flags)
 {
 	unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
@@ -481,6 +635,33 @@ int plpks_signed_update_var(struct plpks_var *var, u64 flags)
 	return rc;
 }
 
+/**
+ * plpks_write_var() - Write the specified variable and its data to PLPKS.
+ * @var: variable to be written into the PLPKS
+ *
+ * The H_PKS_WRITE_OBJECT HCALL writes an object into the PLPKS. The caller must
+ * provide a valid component type for the variable, and the signed update policy
+ * flag must not be set.
+ *
+ * Possible reasons for the returned errno values:
+ *
+ * -ENXIO	if PLPKS is not supported
+ * -EIO		if PLPKS access is blocked due to the LPAR's state
+ *		if PLPKS modification is blocked due to the LPAR's state
+ *		if an error occurred while processing the request
+ * -EINVAL	if invalid authorization parameter
+ *		if invalid object label parameter
+ *		if invalid object label len parameter
+ *		if invalid or unsupported policy declaration
+ *		if invalid input data parameter
+ *		if invalid input data len parameter
+ * -EPERM	if access is denied
+ * -ENOMEM	if unable to store the requested object in the space available
+ * -EBUSY	if unable to handle the request
+ * -EEXIST	if the object label already exists
+ *
+ * Returns: On success 0 is returned, a negative errno if not.
+ */
 int plpks_write_var(struct plpks_var var)
 {
 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
@@ -520,6 +701,30 @@ int plpks_write_var(struct plpks_var var)
 	return rc;
 }
 
+/**
+ * plpks_remove_var() - Remove the specified variable and its data from PLPKS.
+ * @component: metadata prefix in the object label metadata structure
+ * @varos: metadata OS flags in the object label metadata structure
+ * @vname: object label for the object that needs to be removed
+ *
+ * The H_PKS_REMOVE_OBJECT HCALL removes an object from the PLPKS. The removal
+ * is independent of the policy bits that are set.
+ *
+ * Possible reasons for the returned errno values:
+ *
+ * -ENXIO	if PLPKS is not supported
+ * -EIO		if PLPKS access is blocked due to the LPAR's state
+ *		if PLPKS modification is blocked due to the LPAR's state
+ *		if an error occurred while processing the request
+ * -EINVAL	if invalid authorization parameter
+ *		if invalid object label parameter
+ *		if invalid object label len parameter
+ * -EPERM	if access is denied
+ * -ENOENT	if the requested object was not found
+ * -EBUSY	if unable to handle the request
+ *
+ * Returns: On success 0 is returned, a negative errno if not.
+ */
 int plpks_remove_var(char *component, u8 varos, struct plpks_var_name vname)
 {
 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
@@ -619,21 +824,119 @@ static int plpks_read_var(u8 consumer, struct plpks_var *var)
 	return rc;
 }
 
+/**
+ * plpks_read_os_var() - Fetch the data for the specified variable that is
+ * owned by the OS consumer.
+ * @var: variable to be read from the PLPKS
+ *
+ * The consumer or the owner of the object is the os kernel. The
+ * H_PKS_READ_OBJECT HCALL reads an object from the PLPKS. The caller must
+ * allocate the buffer var->data and specify the length for this buffer in
+ * var->datalen. If no buffer is provided, var->datalen will be populated with
+ * the requested object's size.
+ *
+ * Possible reasons for the returned errno values:
+ *
+ * -ENXIO	if PLPKS is not supported
+ * -EIO		if PLPKS access is blocked due to the LPAR's state
+ *		if an error occurred while processing the request
+ * -EINVAL	if invalid authorization parameter
+ *		if invalid object label parameter
+ *		if invalid object label len parameter
+ *		if invalid output data parameter
+ *		if invalid output data len parameter
+ * -EPERM	if access is denied
+ * -ENOENT	if the requested object was not found
+ * -EFBIG	if the requested object couldn't be
+ *		stored in the buffer provided
+ * -EBUSY	if unable to handle the request
+ *
+ * Returns: On success 0 is returned, a negative errno if not.
+ */
 int plpks_read_os_var(struct plpks_var *var)
 {
 	return plpks_read_var(PLPKS_OS_OWNER, var);
 }
 
+/**
+ * plpks_read_fw_var() - Fetch the data for the specified variable that is
+ * owned by the firmware consumer.
+ * @var: variable to be read from the PLPKS
+ *
+ * The consumer or the owner of the object is the firmware. The
+ * H_PKS_READ_OBJECT HCALL reads an object from the PLPKS. The caller must
+ * allocate the buffer var->data and specify the length for this buffer in
+ * var->datalen. If no buffer is provided, var->datalen will be populated with
+ * the requested object's size.
+ *
+ * Possible reasons for the returned errno values:
+ *
+ * -ENXIO	if PLPKS is not supported
+ * -EIO		if PLPKS access is blocked due to the LPAR's state
+ *		if an error occurred while processing the request
+ * -EINVAL	if invalid authorization parameter
+ *		if invalid object label parameter
+ *		if invalid object label len parameter
+ *		if invalid output data parameter
+ *		if invalid output data len parameter
+ * -EPERM	if access is denied
+ * -ENOENT	if the requested object was not found
+ * -EFBIG	if the requested object couldn't be
+ *		stored in the buffer provided
+ * -EBUSY	if unable to handle the request
+ *
+ * Returns: On success 0 is returned, a negative errno if not.
+ */
 int plpks_read_fw_var(struct plpks_var *var)
 {
 	return plpks_read_var(PLPKS_FW_OWNER, var);
 }
 
+/**
+ * plpks_read_bootloader_var() - Fetch the data for the specified variable
+ * owned by the bootloader consumer.
+ * @var: variable to be read from the PLPKS
+ *
+ * The consumer or the owner of the object is the bootloader. The
+ * H_PKS_READ_OBJECT HCALL reads an object from the PLPKS. The caller must
+ * allocate the buffer var->data and specify the length for this buffer in
+ * var->datalen. If no buffer is provided, var->datalen will be populated with
+ * the requested object's size.
+ *
+ * Possible reasons for the returned errno values:
+ *
+ * -ENXIO	if PLPKS is not supported
+ * -EIO		if PLPKS access is blocked due to the LPAR's state
+ *		if an error occurred while processing the request
+ * -EINVAL	if invalid authorization parameter
+ *		if invalid object label parameter
+ *		if invalid object label len parameter
+ *		if invalid output data parameter
+ *		if invalid output data len parameter
+ * -EPERM	if access is denied
+ * -ENOENT	if the requested object was not found
+ * -EFBIG	if the requested object couldn't be
+ *		stored in the buffer provided
+ * -EBUSY	if unable to handle the request
+ *
+ * Returns: On success 0 is returned, a negative errno if not.
+ */
 int plpks_read_bootloader_var(struct plpks_var *var)
 {
 	return plpks_read_var(PLPKS_BOOTLOADER_OWNER, var);
 }
 
+/**
+ * plpks_populate_fdt(): Populates the FDT with the PLPKS password to prepare
+ * for kexec.
+ * @fdt: pointer to the device tree blob
+ *
+ * Upon confirming the existence of the chosen node, invoke fdt_setprop to
+ * populate the device tree with the PLPKS password in order to prepare for
+ * kexec.
+ *
+ * Returns: On success 0 is returned, a negative value if not.
+ */
 int plpks_populate_fdt(void *fdt)
 {
 	int chosen_offset = fdt_path_offset(fdt, "/chosen");
@@ -647,14 +950,19 @@ int plpks_populate_fdt(void *fdt)
 	return fdt_setprop(fdt, chosen_offset, "ibm,plpks-pw", ospassword, ospasswordlength);
 }
 
-// Once a password is registered with the hypervisor it cannot be cleared without
-// rebooting the LPAR, so to keep using the PLPKS across kexec boots we need to
-// recover the previous password from the FDT.
-//
-// There are a few challenges here.  We don't want the password to be visible to
-// users, so we need to clear it from the FDT.  This has to be done in early boot.
-// Clearing it from the FDT would make the FDT's checksum invalid, so we have to
-// manually cause the checksum to be recalculated.
+/**
+ * plpks_early_init_devtree() - Retrieves and clears the PLPKS password from the
+ * DT in early init.
+ *
+ * Once a password is registered with the hypervisor it cannot be cleared
+ * without rebooting the LPAR, so to keep using the PLPKS across kexec boots we
+ * need to recover the previous password from the FDT.
+ *
+ * There are a few challenges here.  We don't want the password to be visible to
+ * users, so we need to clear it from the FDT.  This has to be done in early
+ * boot. Clearing it from the FDT would make the FDT's checksum invalid, so we
+ * have to manually cause the checksum to be recalculated.
+ */
 void __init plpks_early_init_devtree(void)
 {
 	void *fdt = initial_boot_params;
-- 
2.47.3


^ permalink raw reply related

* [PATCH v5 0/6] Extend "trusted" keys to support a new trust source named the PowerVM Key Wrapping Module (PKWM)
From: Srish Srinivasan @ 2026-01-27 14:52 UTC (permalink / raw)
  To: linux-integrity, keyrings, linuxppc-dev
  Cc: maddy, mpe, npiggin, christophe.leroy, James.Bottomley, jarkko,
	zohar, nayna, rnsastry, linux-kernel, linux-security-module,
	ssrish

Power11 has introduced a feature called the PowerVM Key Wrapping Module
(PKWM), where PowerVM in combination with Power LPAR Platform KeyStore
(PLPKS) [1] supports a new feature called "Key Wrapping" [2] to protect
user secrets by wrapping them using a hypervisor generated wrapping key.
This wrapping key is an AES-GCM-256 symmetric key that is stored as an
object in the PLPKS. It has policy based protections that prevents it from
being read out or exposed to the user. This wrapping key can then be used
by the OS to wrap or unwrap secrets via hypervisor calls.

This patchset intends to add the PKWM, which is a combination of IBM
PowerVM and PLPKS, as a new trust source for trusted keys. The wrapping key
does not exist by default and its generation is requested by the kernel at
the time of PKWM initialization. This key is then persisted by the PKWM and
is used for wrapping any kernel provided key, and is never exposed to the
user. The kernel is aware of only the label to this wrapping key.

Along with the PKWM implementation, this patchset includes two preparatory
patches: one fixing the kernel-doc inconsistencies in the PLPKS code and
another reorganizing PLPKS config variables in the sysfs.

Changelog:

v5:

* Patch 1:
  - Add Nayna's Reviewed-by tag
* Patch 2:
  - Add Nayna's Reviewed-by tag
* Patch 3:
  - Add Nayna's Reviewed-by tag
* Patch 4:
  - Fix build error identified by chleroy@kernel.org
  - Add Nayna's Reviewed-by tag
* Patch 5:
  - Add Reviewed-by tags from Nayna and Jarkko

v4:

* Patch 5:
  - Add a per-backend private data pointer in trusted_key_options
    to store a pointer to the backend-specific options structure
  - Minor clean-up

v3:

* Patch 2:
  - Add Mimi's Reviewed-by tag
* Patch 4:
  - Minor tweaks to some print statements
  - Fix typos
* Patch 5:
  - Fix typos
  - Add Mimi's Reviewed-by tag
* Patch 6:
  - Add Mimi's Reviewed-by tag

v2:

* Patch 2:
  - Fix build warning detected by the kernel test bot
* Patch 5:
  - Use pr_debug inside dump_options
  - Replace policyhande with wrap_flags inside dump_options
  - Provide meaningful error messages with error codes

Nayna Jain (1):
  docs: trusted-encryped: add PKWM as a new trust source

Srish Srinivasan (5):
  pseries/plpks: fix kernel-doc comment inconsistencies
  powerpc/pseries: move the PLPKS config inside its own sysfs directory
  pseries/plpks: expose PowerVM wrapping features via the sysfs
  pseries/plpks: add HCALLs for PowerVM Key Wrapping Module
  keys/trusted_keys: establish PKWM as a trusted source

 .../ABI/testing/sysfs-firmware-plpks          |  58 ++
 Documentation/ABI/testing/sysfs-secvar        |  65 --
 .../admin-guide/kernel-parameters.txt         |   1 +
 Documentation/arch/powerpc/papr_hcalls.rst    |  43 ++
 .../security/keys/trusted-encrypted.rst       |  50 ++
 MAINTAINERS                                   |   9 +
 arch/powerpc/include/asm/hvcall.h             |   4 +-
 arch/powerpc/include/asm/plpks.h              |  95 +--
 arch/powerpc/include/asm/secvar.h             |   1 -
 arch/powerpc/kernel/secvar-sysfs.c            |  21 +-
 arch/powerpc/platforms/pseries/Makefile       |   2 +-
 arch/powerpc/platforms/pseries/plpks-secvar.c |  29 -
 arch/powerpc/platforms/pseries/plpks-sysfs.c  |  96 +++
 arch/powerpc/platforms/pseries/plpks.c        | 687 +++++++++++++++++-
 include/keys/trusted-type.h                   |   7 +-
 include/keys/trusted_pkwm.h                   |  33 +
 security/keys/trusted-keys/Kconfig            |   8 +
 security/keys/trusted-keys/Makefile           |   2 +
 security/keys/trusted-keys/trusted_core.c     |   6 +-
 security/keys/trusted-keys/trusted_pkwm.c     | 190 +++++
 20 files changed, 1206 insertions(+), 201 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-firmware-plpks
 create mode 100644 arch/powerpc/platforms/pseries/plpks-sysfs.c
 create mode 100644 include/keys/trusted_pkwm.h
 create mode 100644 security/keys/trusted-keys/trusted_pkwm.c

-- 
2.47.3


^ permalink raw reply

* Re: [PATCH v2] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Dmitry Safonov @ 2026-01-27 14:30 UTC (permalink / raw)
  To: Roberto Sassu
  Cc: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi, linux-integrity, linux-security-module,
	linux-kernel, stable, Dmitry Safonov
In-Reply-To: <16c446c001a96a9878ddec9726430d7001c3f47b.camel@huaweicloud.com>

On Tue, Jan 27, 2026 at 2:28 PM Roberto Sassu
<roberto.sassu@huaweicloud.com> wrote:
>
> On Tue, 2026-01-27 at 14:18 +0000, Dmitry Safonov via B4 Relay wrote:
[..]
> >       /* 2nd: template hash */
> > -     ima_print_digest(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
> > +     if (algo == HASH_ALGO__LAST)
> > +             ima_putc(m, "0", 1);
> > +     else
> > +             ima_print_digest(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
>
> No need, the last one is ok with ima_tpm_chip->allocated_banks[algo_idx].digest_size.

Cool, let me check it and I'll update it in v4.

Thanks,
           Dmitry

^ permalink raw reply

* Re: [PATCH v2] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Roberto Sassu @ 2026-01-27 14:28 UTC (permalink / raw)
  To: dima, Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi
  Cc: linux-integrity, linux-security-module, linux-kernel, stable,
	Dmitry Safonov
In-Reply-To: <20260127-ima-oob-v2-1-f38a18c850cf@arista.com>

On Tue, 2026-01-27 at 14:18 +0000, Dmitry Safonov via B4 Relay wrote:
> From: Dmitry Safonov <dima@arista.com>
> 
> ima_init_crypto() skips initializing ima_algo_array[i] if the alogorithm
> from ima_tpm_chip->allocated_banks[i].crypto_id is not supported.
> It seems avoid adding the unsupported algorithm to ima_algo_array will
> break all the logic that relies on indexing by NR_BANKS(ima_tpm_chip).
> 
> On 6.12.40 I observe the following read out-of-bounds in hash_algo_name:
> 
> > ==================================================================
> > BUG: KASAN: global-out-of-bounds in create_securityfs_measurement_lists+0x396/0x440
> > Read of size 8 at addr ffffffff83e18138 by task swapper/0/1
> > 
> > CPU: 4 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.40 #3
> > Call Trace:
> >  <TASK>
> >  dump_stack_lvl+0x61/0x90
> >  print_report+0xc4/0x580
> >  ? kasan_addr_to_slab+0x26/0x80
> >  ? create_securityfs_measurement_lists+0x396/0x440
> >  kasan_report+0xc2/0x100
> >  ? create_securityfs_measurement_lists+0x396/0x440
> >  create_securityfs_measurement_lists+0x396/0x440
> >  ima_fs_init+0xa3/0x300
> >  ima_init+0x7d/0xd0
> >  init_ima+0x28/0x100
> >  do_one_initcall+0xa6/0x3e0
> >  kernel_init_freeable+0x455/0x740
> >  kernel_init+0x24/0x1d0
> >  ret_from_fork+0x38/0x80
> >  ret_from_fork_asm+0x11/0x20
> >  </TASK>
> > 
> > The buggy address belongs to the variable:
> >  hash_algo_name+0xb8/0x420
> > 
> > The buggy address belongs to the physical page:
> > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x107ce18
> > flags: 0x8000000000002000(reserved|zone=2)
> > raw: 8000000000002000 ffffea0041f38608 ffffea0041f38608 0000000000000000
> > raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
> > page dumped because: kasan: bad access detected
> > 
> > Memory state around the buggy address:
> >  ffffffff83e18000: 00 01 f9 f9 f9 f9 f9 f9 00 01 f9 f9 f9 f9 f9 f9
> >  ffffffff83e18080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > > ffffffff83e18100: 00 00 00 00 00 00 00 f9 f9 f9 f9 f9 00 05 f9 f9
> >                                         ^
> >  ffffffff83e18180: f9 f9 f9 f9 00 00 00 00 00 00 00 04 f9 f9 f9 f9
> >  ffffffff83e18200: 00 00 00 00 00 00 00 00 04 f9 f9 f9 f9 f9 f9 f9
> > ==================================================================
> 
> Seems like the TPM chip supports sha3_256, which isn't yet in
> tpm_algorithms:
> > tpm tpm0: TPM with unsupported bank algorithm 0x0027
> 
> Grepping HASH_ALGO__LAST in security/integrity/ima/ shows that is
> the check other logic relies on, so add files under TPM_ALG_<ID>
> and print 0 as their hash_digest_size.
> 
> This is how it looks on the test machine I have:
> > # ls -1 /sys/kernel/security/ima/
> > ascii_runtime_measurements
> > ascii_runtime_measurements_TPM_ALG_27
> > ascii_runtime_measurements_sha1
> > ascii_runtime_measurements_sha256
> > binary_runtime_measurements
> > binary_runtime_measurements_TPM_ALG_27
> > binary_runtime_measurements_sha1
> > binary_runtime_measurements_sha256
> > policy
> > runtime_measurements_count
> > violations
> 
> Fixes: 9fa8e7625008 ("ima: add crypto agility support for template-hash algorithm")
> Signed-off-by: Dmitry Safonov <dima@arista.com>
> Cc: Enrico Bravi <enrico.bravi@polito.it>
> Cc: Silvia Sisinni <silvia.sisinni@polito.it>
> Cc: Roberto Sassu <roberto.sassu@huawei.com>
> Cc: Mimi Zohar <zohar@linux.ibm.com>
> ---
> Changes in v2:
> - Instead of skipping unknown algorithms, add files under their TPM_ALG_ID (Roberto Sassu)
> - Fix spelling (Roberto Sassu)
> - Copy @stable on the fix
> - Link to v1: https://lore.kernel.org/r/20260127-ima-oob-v1-1-2d42f3418e57@arista.com
> ---
>  security/integrity/ima/ima_fs.c | 26 ++++++++++++++++++++------
>  1 file changed, 20 insertions(+), 6 deletions(-)
> 
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index 012a58959ff0..3b442e3f84d0 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -160,7 +160,10 @@ int ima_measurements_show(struct seq_file *m, void *v)
>  	ima_putc(m, &pcr, sizeof(e->pcr));
>  
>  	/* 2nd: template digest */
> -	ima_putc(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
> +	if (algo == HASH_ALGO__LAST)
> +		ima_putc(m, "0", 1);
> +	else
> +		ima_putc(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
>  
>  	/* 3rd: template name size */
>  	namelen = !ima_canonical_fmt ? strlen(template_name) :
> @@ -252,7 +255,10 @@ static int ima_ascii_measurements_show(struct seq_file *m, void *v)
>  	seq_printf(m, "%2d ", e->pcr);
>  
>  	/* 2nd: template hash */
> -	ima_print_digest(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
> +	if (algo == HASH_ALGO__LAST)
> +		ima_putc(m, "0", 1);
> +	else
> +		ima_print_digest(m, e->digests[algo_idx].digest, hash_digest_size[algo]);

No need, the last one is ok with ima_tpm_chip->allocated_banks[algo_idx].digest_size.

Roberto

>  
>  	/* 3th:  template name */
>  	seq_printf(m, " %s", template_name);
> @@ -404,16 +410,24 @@ static int __init create_securityfs_measurement_lists(void)
>  		char file_name[NAME_MAX + 1];
>  		struct dentry *dentry;
>  
> -		sprintf(file_name, "ascii_runtime_measurements_%s",
> -			hash_algo_name[algo]);
> +		if (algo == HASH_ALGO__LAST)
> +			sprintf(file_name, "ascii_runtime_measurements_TPM_ALG_%x",
> +				ima_tpm_chip->allocated_banks[i].alg_id);
> +		else
> +			sprintf(file_name, "ascii_runtime_measurements_%s",
> +				hash_algo_name[algo]);
>  		dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,
>  						ima_dir, (void *)(uintptr_t)i,
>  						&ima_ascii_measurements_ops);
>  		if (IS_ERR(dentry))
>  			return PTR_ERR(dentry);
>  
> -		sprintf(file_name, "binary_runtime_measurements_%s",
> -			hash_algo_name[algo]);
> +		if (algo == HASH_ALGO__LAST)
> +			sprintf(file_name, "binary_runtime_measurements_TPM_ALG_%x",
> +				ima_tpm_chip->allocated_banks[i].alg_id);
> +		else
> +			sprintf(file_name, "binary_runtime_measurements_%s",
> +				hash_algo_name[algo]);
>  		dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,
>  						ima_dir, (void *)(uintptr_t)i,
>  						&ima_measurements_ops);
> 
> ---
> base-commit: 63804fed149a6750ffd28610c5c1c98cce6bd377
> change-id: 20260127-ima-oob-9fa83a634d7b
> 
> Best regards,


^ permalink raw reply

* Re: [PATCH v2] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Dmitry Safonov @ 2026-01-27 14:24 UTC (permalink / raw)
  To: dima
  Cc: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi, linux-integrity, linux-security-module,
	linux-kernel, stable, Dmitry Safonov
In-Reply-To: <20260127-ima-oob-v2-1-f38a18c850cf@arista.com>

On Tue, Jan 27, 2026 at 2:18 PM Dmitry Safonov via B4 Relay
<devnull+dima.arista.com@kernel.org> wrote:
>
> From: Dmitry Safonov <dima@arista.com>
>
> ima_init_crypto() skips initializing ima_algo_array[i] if the alogorithm

Managed to forget correcting the spelling here ^
Please, ignore v2, version 3 is here:
https://lore.kernel.org/lkml/20260127-ima-oob-v3-1-1dd09f4c2a6a@arista.com/

Excuses for the noise,
           Dmitry

^ permalink raw reply

* [PATCH v3] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Dmitry Safonov via B4 Relay @ 2026-01-27 14:21 UTC (permalink / raw)
  To: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi
  Cc: linux-integrity, linux-security-module, linux-kernel, stable,
	Dmitry Safonov, Dmitry Safonov

From: Dmitry Safonov <dima@arista.com>

ima_init_crypto() skips initializing ima_algo_array[i] if the algorithm
from ima_tpm_chip->allocated_banks[i].crypto_id is not supported.
It seems avoid adding the unsupported algorithm to ima_algo_array will
break all the logic that relies on indexing by NR_BANKS(ima_tpm_chip).

On 6.12.40 I observe the following read out-of-bounds in hash_algo_name:

> ==================================================================
> BUG: KASAN: global-out-of-bounds in create_securityfs_measurement_lists+0x396/0x440
> Read of size 8 at addr ffffffff83e18138 by task swapper/0/1
>
> CPU: 4 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.40 #3
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x61/0x90
>  print_report+0xc4/0x580
>  ? kasan_addr_to_slab+0x26/0x80
>  ? create_securityfs_measurement_lists+0x396/0x440
>  kasan_report+0xc2/0x100
>  ? create_securityfs_measurement_lists+0x396/0x440
>  create_securityfs_measurement_lists+0x396/0x440
>  ima_fs_init+0xa3/0x300
>  ima_init+0x7d/0xd0
>  init_ima+0x28/0x100
>  do_one_initcall+0xa6/0x3e0
>  kernel_init_freeable+0x455/0x740
>  kernel_init+0x24/0x1d0
>  ret_from_fork+0x38/0x80
>  ret_from_fork_asm+0x11/0x20
>  </TASK>
>
> The buggy address belongs to the variable:
>  hash_algo_name+0xb8/0x420
>
> The buggy address belongs to the physical page:
> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x107ce18
> flags: 0x8000000000002000(reserved|zone=2)
> raw: 8000000000002000 ffffea0041f38608 ffffea0041f38608 0000000000000000
> raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  ffffffff83e18000: 00 01 f9 f9 f9 f9 f9 f9 00 01 f9 f9 f9 f9 f9 f9
>  ffffffff83e18080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffffffff83e18100: 00 00 00 00 00 00 00 f9 f9 f9 f9 f9 00 05 f9 f9
>                                         ^
>  ffffffff83e18180: f9 f9 f9 f9 00 00 00 00 00 00 00 04 f9 f9 f9 f9
>  ffffffff83e18200: 00 00 00 00 00 00 00 00 04 f9 f9 f9 f9 f9 f9 f9
> ==================================================================

Seems like the TPM chip supports sha3_256, which isn't yet in
tpm_algorithms:
> tpm tpm0: TPM with unsupported bank algorithm 0x0027

Grepping HASH_ALGO__LAST in security/integrity/ima/ shows that is
the check other logic relies on, so add files under TPM_ALG_<ID>
and print 0 as their hash_digest_size.

This is how it looks on the test machine I have:
> # ls -1 /sys/kernel/security/ima/
> ascii_runtime_measurements
> ascii_runtime_measurements_TPM_ALG_27
> ascii_runtime_measurements_sha1
> ascii_runtime_measurements_sha256
> binary_runtime_measurements
> binary_runtime_measurements_TPM_ALG_27
> binary_runtime_measurements_sha1
> binary_runtime_measurements_sha256
> policy
> runtime_measurements_count
> violations

Fixes: 9fa8e7625008 ("ima: add crypto agility support for template-hash algorithm")
Signed-off-by: Dmitry Safonov <dima@arista.com>
Cc: Enrico Bravi <enrico.bravi@polito.it>
Cc: Silvia Sisinni <silvia.sisinni@polito.it>
Cc: Roberto Sassu <roberto.sassu@huawei.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
---
Changes in v3:
- Now fix the spelling *for real* (sorry, messed it up in v2)
- Link to v2: https://lore.kernel.org/r/20260127-ima-oob-v2-1-f38a18c850cf@arista.com

Changes in v2:
- Instead of skipping unknown algorithms, add files under their TPM_ALG_ID (Roberto Sassu)
- Fix spelling (Roberto Sassu)
- Copy @stable on the fix
- Link to v1: https://lore.kernel.org/r/20260127-ima-oob-v1-1-2d42f3418e57@arista.com
---
 security/integrity/ima/ima_fs.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 012a58959ff0..3b442e3f84d0 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -160,7 +160,10 @@ int ima_measurements_show(struct seq_file *m, void *v)
 	ima_putc(m, &pcr, sizeof(e->pcr));
 
 	/* 2nd: template digest */
-	ima_putc(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
+	if (algo == HASH_ALGO__LAST)
+		ima_putc(m, "0", 1);
+	else
+		ima_putc(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
 
 	/* 3rd: template name size */
 	namelen = !ima_canonical_fmt ? strlen(template_name) :
@@ -252,7 +255,10 @@ static int ima_ascii_measurements_show(struct seq_file *m, void *v)
 	seq_printf(m, "%2d ", e->pcr);
 
 	/* 2nd: template hash */
-	ima_print_digest(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
+	if (algo == HASH_ALGO__LAST)
+		ima_putc(m, "0", 1);
+	else
+		ima_print_digest(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
 
 	/* 3th:  template name */
 	seq_printf(m, " %s", template_name);
@@ -404,16 +410,24 @@ static int __init create_securityfs_measurement_lists(void)
 		char file_name[NAME_MAX + 1];
 		struct dentry *dentry;
 
-		sprintf(file_name, "ascii_runtime_measurements_%s",
-			hash_algo_name[algo]);
+		if (algo == HASH_ALGO__LAST)
+			sprintf(file_name, "ascii_runtime_measurements_TPM_ALG_%x",
+				ima_tpm_chip->allocated_banks[i].alg_id);
+		else
+			sprintf(file_name, "ascii_runtime_measurements_%s",
+				hash_algo_name[algo]);
 		dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,
 						ima_dir, (void *)(uintptr_t)i,
 						&ima_ascii_measurements_ops);
 		if (IS_ERR(dentry))
 			return PTR_ERR(dentry);
 
-		sprintf(file_name, "binary_runtime_measurements_%s",
-			hash_algo_name[algo]);
+		if (algo == HASH_ALGO__LAST)
+			sprintf(file_name, "binary_runtime_measurements_TPM_ALG_%x",
+				ima_tpm_chip->allocated_banks[i].alg_id);
+		else
+			sprintf(file_name, "binary_runtime_measurements_%s",
+				hash_algo_name[algo]);
 		dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,
 						ima_dir, (void *)(uintptr_t)i,
 						&ima_measurements_ops);

---
base-commit: 63804fed149a6750ffd28610c5c1c98cce6bd377
change-id: 20260127-ima-oob-9fa83a634d7b

Best regards,
-- 
Dmitry Safonov <dima@arista.com>



^ permalink raw reply related

* [PATCH v2] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Dmitry Safonov via B4 Relay @ 2026-01-27 14:18 UTC (permalink / raw)
  To: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi
  Cc: linux-integrity, linux-security-module, linux-kernel, stable,
	Dmitry Safonov, Dmitry Safonov

From: Dmitry Safonov <dima@arista.com>

ima_init_crypto() skips initializing ima_algo_array[i] if the alogorithm
from ima_tpm_chip->allocated_banks[i].crypto_id is not supported.
It seems avoid adding the unsupported algorithm to ima_algo_array will
break all the logic that relies on indexing by NR_BANKS(ima_tpm_chip).

On 6.12.40 I observe the following read out-of-bounds in hash_algo_name:

> ==================================================================
> BUG: KASAN: global-out-of-bounds in create_securityfs_measurement_lists+0x396/0x440
> Read of size 8 at addr ffffffff83e18138 by task swapper/0/1
>
> CPU: 4 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.40 #3
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x61/0x90
>  print_report+0xc4/0x580
>  ? kasan_addr_to_slab+0x26/0x80
>  ? create_securityfs_measurement_lists+0x396/0x440
>  kasan_report+0xc2/0x100
>  ? create_securityfs_measurement_lists+0x396/0x440
>  create_securityfs_measurement_lists+0x396/0x440
>  ima_fs_init+0xa3/0x300
>  ima_init+0x7d/0xd0
>  init_ima+0x28/0x100
>  do_one_initcall+0xa6/0x3e0
>  kernel_init_freeable+0x455/0x740
>  kernel_init+0x24/0x1d0
>  ret_from_fork+0x38/0x80
>  ret_from_fork_asm+0x11/0x20
>  </TASK>
>
> The buggy address belongs to the variable:
>  hash_algo_name+0xb8/0x420
>
> The buggy address belongs to the physical page:
> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x107ce18
> flags: 0x8000000000002000(reserved|zone=2)
> raw: 8000000000002000 ffffea0041f38608 ffffea0041f38608 0000000000000000
> raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  ffffffff83e18000: 00 01 f9 f9 f9 f9 f9 f9 00 01 f9 f9 f9 f9 f9 f9
>  ffffffff83e18080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffffffff83e18100: 00 00 00 00 00 00 00 f9 f9 f9 f9 f9 00 05 f9 f9
>                                         ^
>  ffffffff83e18180: f9 f9 f9 f9 00 00 00 00 00 00 00 04 f9 f9 f9 f9
>  ffffffff83e18200: 00 00 00 00 00 00 00 00 04 f9 f9 f9 f9 f9 f9 f9
> ==================================================================

Seems like the TPM chip supports sha3_256, which isn't yet in
tpm_algorithms:
> tpm tpm0: TPM with unsupported bank algorithm 0x0027

Grepping HASH_ALGO__LAST in security/integrity/ima/ shows that is
the check other logic relies on, so add files under TPM_ALG_<ID>
and print 0 as their hash_digest_size.

This is how it looks on the test machine I have:
> # ls -1 /sys/kernel/security/ima/
> ascii_runtime_measurements
> ascii_runtime_measurements_TPM_ALG_27
> ascii_runtime_measurements_sha1
> ascii_runtime_measurements_sha256
> binary_runtime_measurements
> binary_runtime_measurements_TPM_ALG_27
> binary_runtime_measurements_sha1
> binary_runtime_measurements_sha256
> policy
> runtime_measurements_count
> violations

Fixes: 9fa8e7625008 ("ima: add crypto agility support for template-hash algorithm")
Signed-off-by: Dmitry Safonov <dima@arista.com>
Cc: Enrico Bravi <enrico.bravi@polito.it>
Cc: Silvia Sisinni <silvia.sisinni@polito.it>
Cc: Roberto Sassu <roberto.sassu@huawei.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
---
Changes in v2:
- Instead of skipping unknown algorithms, add files under their TPM_ALG_ID (Roberto Sassu)
- Fix spelling (Roberto Sassu)
- Copy @stable on the fix
- Link to v1: https://lore.kernel.org/r/20260127-ima-oob-v1-1-2d42f3418e57@arista.com
---
 security/integrity/ima/ima_fs.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 012a58959ff0..3b442e3f84d0 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -160,7 +160,10 @@ int ima_measurements_show(struct seq_file *m, void *v)
 	ima_putc(m, &pcr, sizeof(e->pcr));
 
 	/* 2nd: template digest */
-	ima_putc(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
+	if (algo == HASH_ALGO__LAST)
+		ima_putc(m, "0", 1);
+	else
+		ima_putc(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
 
 	/* 3rd: template name size */
 	namelen = !ima_canonical_fmt ? strlen(template_name) :
@@ -252,7 +255,10 @@ static int ima_ascii_measurements_show(struct seq_file *m, void *v)
 	seq_printf(m, "%2d ", e->pcr);
 
 	/* 2nd: template hash */
-	ima_print_digest(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
+	if (algo == HASH_ALGO__LAST)
+		ima_putc(m, "0", 1);
+	else
+		ima_print_digest(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
 
 	/* 3th:  template name */
 	seq_printf(m, " %s", template_name);
@@ -404,16 +410,24 @@ static int __init create_securityfs_measurement_lists(void)
 		char file_name[NAME_MAX + 1];
 		struct dentry *dentry;
 
-		sprintf(file_name, "ascii_runtime_measurements_%s",
-			hash_algo_name[algo]);
+		if (algo == HASH_ALGO__LAST)
+			sprintf(file_name, "ascii_runtime_measurements_TPM_ALG_%x",
+				ima_tpm_chip->allocated_banks[i].alg_id);
+		else
+			sprintf(file_name, "ascii_runtime_measurements_%s",
+				hash_algo_name[algo]);
 		dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,
 						ima_dir, (void *)(uintptr_t)i,
 						&ima_ascii_measurements_ops);
 		if (IS_ERR(dentry))
 			return PTR_ERR(dentry);
 
-		sprintf(file_name, "binary_runtime_measurements_%s",
-			hash_algo_name[algo]);
+		if (algo == HASH_ALGO__LAST)
+			sprintf(file_name, "binary_runtime_measurements_TPM_ALG_%x",
+				ima_tpm_chip->allocated_banks[i].alg_id);
+		else
+			sprintf(file_name, "binary_runtime_measurements_%s",
+				hash_algo_name[algo]);
 		dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,
 						ima_dir, (void *)(uintptr_t)i,
 						&ima_measurements_ops);

---
base-commit: 63804fed149a6750ffd28610c5c1c98cce6bd377
change-id: 20260127-ima-oob-9fa83a634d7b

Best regards,
-- 
Dmitry Safonov <dima@arista.com>



^ permalink raw reply related

* Re: [PATCH] ima_setup.sh: Fix check of signed policy requirement
From: Petr Vorel @ 2026-01-27 13:17 UTC (permalink / raw)
  To: ltp; +Cc: Mimi Zohar, linux-integrity
In-Reply-To: <20260121083343.127613-1-pvorel@suse.cz>

Hi Mimi, all,

> Kernel code in arch_get_ima_policy() depends also on
> CONFIG_IMA_ARCH_POLICY added in v5.0:
> d958083a8f640 ("x86/ima: define arch_get_ima_policy() for x86")

> Fixes: c38b528783 ("ima_{conditionals, policy}: Handle policy required to be signed")
> Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> Hi Mimi, all,

> FYI I'd like to merge it this week to get it into LTP release.

> Kind regards,
> Petr

I dared to merge this to get it into upcoming LTP release (this/next week).

Kind regards,
Petr

>  testcases/kernel/security/integrity/ima/tests/ima_setup.sh | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

> diff --git a/testcases/kernel/security/integrity/ima/tests/ima_setup.sh b/testcases/kernel/security/integrity/ima/tests/ima_setup.sh
> index 1bce78d425..df0b8d1532 100644
> --- a/testcases/kernel/security/integrity/ima/tests/ima_setup.sh
> +++ b/testcases/kernel/security/integrity/ima/tests/ima_setup.sh
> @@ -466,10 +466,11 @@ require_evmctl()
>  }

>  # 56dc986a6b20b ("ima: require signed IMA policy when UEFI secure boot is enabled") # v6.5-rc4
> +# d958083a8f640 ("x86/ima: define arch_get_ima_policy() for x86") # v5.0
>  check_need_signed_policy()
>  {
>  	tst_secureboot_enabled && tst_kvcmp -ge '6.5' && tst_require_kconfigs \
> -		'CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY'
> +		'CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY,CONFIG_IMA_ARCH_POLICY'
>  }

>  # loop device is needed to use only for tmpfs

^ permalink raw reply

* Re: [PATCH] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Dmitry Safonov @ 2026-01-27 10:12 UTC (permalink / raw)
  To: Roberto Sassu
  Cc: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi, linux-integrity, linux-security-module,
	linux-kernel, Dmitry Safonov
In-Reply-To: <caebe20b5f30cb76ba8021443ba50ad06a2ef570.camel@huaweicloud.com>

On Tue, Jan 27, 2026 at 10:02 AM Roberto Sassu
<roberto.sassu@huaweicloud.com> wrote:
[..]
> > I'm not quite sure what you mean. `algo` here is HASH_ALGO__LAST as
> > you see by the check added. As it's initialized by
> > ima_tpm_chip->allocated_banks[i].crypto_id, I presume it's
> > HASH_ALGO__LAST there as well (didn't check this assumption though).
> > Do you mean to print hex value of HASH_ALGO__LAST?
>
> Even if you don't have the crypto ID because the TPM ID is not mapped,
> you can still use the TPM ID (ima_tpm_chip->allocated_banks[i].alg_id).
>
> I wanted to have a file name that includes the TPM ID.

I see, thanks, I'll try this.

Thanks,
           Dmitry

^ permalink raw reply

* Re: [PATCH] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Roberto Sassu @ 2026-01-27 10:02 UTC (permalink / raw)
  To: Dmitry Safonov
  Cc: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi, linux-integrity, linux-security-module,
	linux-kernel, Dmitry Safonov
In-Reply-To: <CAGrbwDRgQShh==Vb_8QWoByKV-HXAwV_CGyAoAzjRrHU9c2KbQ@mail.gmail.com>

On Tue, 2026-01-27 at 09:55 +0000, Dmitry Safonov wrote:
> On Tue, Jan 27, 2026 at 9:15 AM Roberto Sassu
> <roberto.sassu@huaweicloud.com> wrote:
> > 
> > On Tue, 2026-01-27 at 03:05 +0000, Dmitry Safonov via B4 Relay wrote:
> > > From: Dmitry Safonov <dima@arista.com>
> > > 
> > > ima_init_crypto() skips initializing ima_algo_array[i] if the alogorithm
> > 
> > Algorithm.
> 
> Thanks.
> 
> [..]
> > > --- a/security/integrity/ima/ima_fs.c
> > > +++ b/security/integrity/ima/ima_fs.c
> > > @@ -404,6 +404,9 @@ static int __init create_securityfs_measurement_lists(void)
> > >               char file_name[NAME_MAX + 1];
> > >               struct dentry *dentry;
> > > 
> > > +             if (algo == HASH_ALGO__LAST)
> > > +                     continue;
> > > +
> > >               sprintf(file_name, "ascii_runtime_measurements_%s",
> > >                       hash_algo_name[algo]);
> > 
> > Thanks, but I think we can also print the unsupported digests, since
> > they are there. Since we don't have the algorithm name, we can make
> > ours like tpm_<algo hex>.
> 
> I'm not quite sure what you mean. `algo` here is HASH_ALGO__LAST as
> you see by the check added. As it's initialized by
> ima_tpm_chip->allocated_banks[i].crypto_id, I presume it's
> HASH_ALGO__LAST there as well (didn't check this assumption though).
> Do you mean to print hex value of HASH_ALGO__LAST?

Even if you don't have the crypto ID because the TPM ID is not mapped,
you can still use the TPM ID (ima_tpm_chip->allocated_banks[i].alg_id).

I wanted to have a file name that includes the TPM ID.

Roberto

> > Once this is fixed, you can try to make SHA3_256 supported. Add the
> > TPM_ALG_SHA3_256 definition in tpm.h and the mapping in tpm2-cmd.c
> > (array tpm2_hash_map).
> 
> Yeah, I thought of doing this, asked the related folks and they said
> it might be worth if it's a simple/trivial patch. Will try if time
> permits, somewhat busy with bug fixes at this moment. This one is just
> a fix for read out-of-bounds for -stable (and I managed to forget to
> Cc them! hehe).
> 
> Going to send v2 with the typo fix and -stable Cc'ed if that sounds good to you.
> 
> > 
> > Thanks
> > 
> > Roberto
> [..]
> 
> Thanks,
>             Dmitry


^ permalink raw reply

* Re: [PATCH] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Dmitry Safonov @ 2026-01-27  9:55 UTC (permalink / raw)
  To: Roberto Sassu
  Cc: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi, linux-integrity, linux-security-module,
	linux-kernel, Dmitry Safonov
In-Reply-To: <b873ba2c8057aa749aa0d058002a30776d0a5248.camel@huaweicloud.com>

On Tue, Jan 27, 2026 at 9:15 AM Roberto Sassu
<roberto.sassu@huaweicloud.com> wrote:
>
> On Tue, 2026-01-27 at 03:05 +0000, Dmitry Safonov via B4 Relay wrote:
> > From: Dmitry Safonov <dima@arista.com>
> >
> > ima_init_crypto() skips initializing ima_algo_array[i] if the alogorithm
>
> Algorithm.

Thanks.

[..]
> > --- a/security/integrity/ima/ima_fs.c
> > +++ b/security/integrity/ima/ima_fs.c
> > @@ -404,6 +404,9 @@ static int __init create_securityfs_measurement_lists(void)
> >               char file_name[NAME_MAX + 1];
> >               struct dentry *dentry;
> >
> > +             if (algo == HASH_ALGO__LAST)
> > +                     continue;
> > +
> >               sprintf(file_name, "ascii_runtime_measurements_%s",
> >                       hash_algo_name[algo]);
>
> Thanks, but I think we can also print the unsupported digests, since
> they are there. Since we don't have the algorithm name, we can make
> ours like tpm_<algo hex>.

I'm not quite sure what you mean. `algo` here is HASH_ALGO__LAST as
you see by the check added. As it's initialized by
ima_tpm_chip->allocated_banks[i].crypto_id, I presume it's
HASH_ALGO__LAST there as well (didn't check this assumption though).
Do you mean to print hex value of HASH_ALGO__LAST?

> Once this is fixed, you can try to make SHA3_256 supported. Add the
> TPM_ALG_SHA3_256 definition in tpm.h and the mapping in tpm2-cmd.c
> (array tpm2_hash_map).

Yeah, I thought of doing this, asked the related folks and they said
it might be worth if it's a simple/trivial patch. Will try if time
permits, somewhat busy with bug fixes at this moment. This one is just
a fix for read out-of-bounds for -stable (and I managed to forget to
Cc them! hehe).

Going to send v2 with the typo fix and -stable Cc'ed if that sounds good to you.

>
> Thanks
>
> Roberto
[..]

Thanks,
            Dmitry

^ permalink raw reply

* Re: [PATCH] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Roberto Sassu @ 2026-01-27  9:14 UTC (permalink / raw)
  To: dima, Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi
  Cc: linux-integrity, linux-security-module, linux-kernel,
	Dmitry Safonov
In-Reply-To: <20260127-ima-oob-v1-1-2d42f3418e57@arista.com>

On Tue, 2026-01-27 at 03:05 +0000, Dmitry Safonov via B4 Relay wrote:
> From: Dmitry Safonov <dima@arista.com>
> 
> ima_init_crypto() skips initializing ima_algo_array[i] if the alogorithm

Algorithm.

> from ima_tpm_chip->allocated_banks[i].crypto_id is not supported.
> It seems avoid adding the unsupported algorithm to ima_algo_array will
> break all the logic that relies on indexing by NR_BANKS(ima_tpm_chip).
> 
> Grepping HASH_ALGO__LAST in security/integrity/ima/ shows that is
> the check other logic relies on, so make
> create_securityfs_measurement_lists() ignore unknown algorithms.
> 
> On 6.12.40 I observe the following read out-of-bounds in hash_algo_name:
> 
> > ==================================================================
> > BUG: KASAN: global-out-of-bounds in create_securityfs_measurement_lists+0x396/0x440
> > Read of size 8 at addr ffffffff83e18138 by task swapper/0/1
> > 
> > CPU: 4 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.40 #3
> > Call Trace:
> >  <TASK>
> >  dump_stack_lvl+0x61/0x90
> >  print_report+0xc4/0x580
> >  ? kasan_addr_to_slab+0x26/0x80
> >  ? create_securityfs_measurement_lists+0x396/0x440
> >  kasan_report+0xc2/0x100
> >  ? create_securityfs_measurement_lists+0x396/0x440
> >  create_securityfs_measurement_lists+0x396/0x440
> >  ima_fs_init+0xa3/0x300
> >  ima_init+0x7d/0xd0
> >  init_ima+0x28/0x100
> >  do_one_initcall+0xa6/0x3e0
> >  kernel_init_freeable+0x455/0x740
> >  kernel_init+0x24/0x1d0
> >  ret_from_fork+0x38/0x80
> >  ret_from_fork_asm+0x11/0x20
> >  </TASK>
> > 
> > The buggy address belongs to the variable:
> >  hash_algo_name+0xb8/0x420
> > 
> > The buggy address belongs to the physical page:
> > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x107ce18
> > flags: 0x8000000000002000(reserved|zone=2)
> > raw: 8000000000002000 ffffea0041f38608 ffffea0041f38608 0000000000000000
> > raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
> > page dumped because: kasan: bad access detected
> > 
> > Memory state around the buggy address:
> >  ffffffff83e18000: 00 01 f9 f9 f9 f9 f9 f9 00 01 f9 f9 f9 f9 f9 f9
> >  ffffffff83e18080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > > ffffffff83e18100: 00 00 00 00 00 00 00 f9 f9 f9 f9 f9 00 05 f9 f9
> >                                         ^
> >  ffffffff83e18180: f9 f9 f9 f9 00 00 00 00 00 00 00 04 f9 f9 f9 f9
> >  ffffffff83e18200: 00 00 00 00 00 00 00 00 04 f9 f9 f9 f9 f9 f9 f9
> > ==================================================================
> 
> Seems like the TPM chip supports sha3_256, which isn't yet in
> tpm_algorithms:
> > tpm tpm0: TPM with unsupported bank algorithm 0x0027
> 
> Fixes: 9fa8e7625008 ("ima: add crypto agility support for template-hash algorithm")
> Signed-off-by: Dmitry Safonov <dima@arista.com>
> Cc: Enrico Bravi <enrico.bravi@polito.it>
> Cc: Silvia Sisinni <silvia.sisinni@polito.it>
> Cc: Roberto Sassu <roberto.sassu@huawei.com>
> Cc: Mimi Zohar <zohar@linux.ibm.com>
> ---
>  security/integrity/ima/ima_fs.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index 012a58959ff0..e9283229acea 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -404,6 +404,9 @@ static int __init create_securityfs_measurement_lists(void)
>  		char file_name[NAME_MAX + 1];
>  		struct dentry *dentry;
>  
> +		if (algo == HASH_ALGO__LAST)
> +			continue;
> +
>  		sprintf(file_name, "ascii_runtime_measurements_%s",
>  			hash_algo_name[algo]);

Thanks, but I think we can also print the unsupported digests, since
they are there. Since we don't have the algorithm name, we can make
ours like tpm_<algo hex>.

Once this is fixed, you can try to make SHA3_256 supported. Add the
TPM_ALG_SHA3_256 definition in tpm.h and the mapping in tpm2-cmd.c
(array tpm2_hash_map).

Thanks

Roberto

>  		dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,
> 
> ---
> base-commit: 63804fed149a6750ffd28610c5c1c98cce6bd377
> change-id: 20260127-ima-oob-9fa83a634d7b
> 
> Best regards,


^ permalink raw reply

* [PATCH] ima_fs: Avoid creating measurement lists for unsupported hash algos
From: Dmitry Safonov via B4 Relay @ 2026-01-27  3:05 UTC (permalink / raw)
  To: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Paul Moore, James Morris, Serge E. Hallyn, Silvia Sisinni,
	Enrico Bravi
  Cc: linux-integrity, linux-security-module, linux-kernel,
	Dmitry Safonov, Dmitry Safonov

From: Dmitry Safonov <dima@arista.com>

ima_init_crypto() skips initializing ima_algo_array[i] if the alogorithm
from ima_tpm_chip->allocated_banks[i].crypto_id is not supported.
It seems avoid adding the unsupported algorithm to ima_algo_array will
break all the logic that relies on indexing by NR_BANKS(ima_tpm_chip).

Grepping HASH_ALGO__LAST in security/integrity/ima/ shows that is
the check other logic relies on, so make
create_securityfs_measurement_lists() ignore unknown algorithms.

On 6.12.40 I observe the following read out-of-bounds in hash_algo_name:

> ==================================================================
> BUG: KASAN: global-out-of-bounds in create_securityfs_measurement_lists+0x396/0x440
> Read of size 8 at addr ffffffff83e18138 by task swapper/0/1
>
> CPU: 4 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.40 #3
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x61/0x90
>  print_report+0xc4/0x580
>  ? kasan_addr_to_slab+0x26/0x80
>  ? create_securityfs_measurement_lists+0x396/0x440
>  kasan_report+0xc2/0x100
>  ? create_securityfs_measurement_lists+0x396/0x440
>  create_securityfs_measurement_lists+0x396/0x440
>  ima_fs_init+0xa3/0x300
>  ima_init+0x7d/0xd0
>  init_ima+0x28/0x100
>  do_one_initcall+0xa6/0x3e0
>  kernel_init_freeable+0x455/0x740
>  kernel_init+0x24/0x1d0
>  ret_from_fork+0x38/0x80
>  ret_from_fork_asm+0x11/0x20
>  </TASK>
>
> The buggy address belongs to the variable:
>  hash_algo_name+0xb8/0x420
>
> The buggy address belongs to the physical page:
> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x107ce18
> flags: 0x8000000000002000(reserved|zone=2)
> raw: 8000000000002000 ffffea0041f38608 ffffea0041f38608 0000000000000000
> raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  ffffffff83e18000: 00 01 f9 f9 f9 f9 f9 f9 00 01 f9 f9 f9 f9 f9 f9
>  ffffffff83e18080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffffffff83e18100: 00 00 00 00 00 00 00 f9 f9 f9 f9 f9 00 05 f9 f9
>                                         ^
>  ffffffff83e18180: f9 f9 f9 f9 00 00 00 00 00 00 00 04 f9 f9 f9 f9
>  ffffffff83e18200: 00 00 00 00 00 00 00 00 04 f9 f9 f9 f9 f9 f9 f9
> ==================================================================

Seems like the TPM chip supports sha3_256, which isn't yet in
tpm_algorithms:
> tpm tpm0: TPM with unsupported bank algorithm 0x0027

Fixes: 9fa8e7625008 ("ima: add crypto agility support for template-hash algorithm")
Signed-off-by: Dmitry Safonov <dima@arista.com>
Cc: Enrico Bravi <enrico.bravi@polito.it>
Cc: Silvia Sisinni <silvia.sisinni@polito.it>
Cc: Roberto Sassu <roberto.sassu@huawei.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/ima/ima_fs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 012a58959ff0..e9283229acea 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -404,6 +404,9 @@ static int __init create_securityfs_measurement_lists(void)
 		char file_name[NAME_MAX + 1];
 		struct dentry *dentry;
 
+		if (algo == HASH_ALGO__LAST)
+			continue;
+
 		sprintf(file_name, "ascii_runtime_measurements_%s",
 			hash_algo_name[algo]);
 		dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,

---
base-commit: 63804fed149a6750ffd28610c5c1c98cce6bd377
change-id: 20260127-ima-oob-9fa83a634d7b

Best regards,
-- 
Dmitry Safonov <dima@arista.com>



^ permalink raw reply related

* Re: IMA and PQC
From: Mimi Zohar @ 2026-01-26 22:54 UTC (permalink / raw)
  To: David Howells
  Cc: Simo Sorce, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Eric Biggers, linux-integrity, linux-crypto, keyrings,
	linux-modules, linux-kernel
In-Reply-To: <1988760.1769463419@warthog.procyon.org.uk>

On Mon, 2026-01-26 at 21:36 +0000, David Howells wrote:
> Mimi Zohar <zohar@linux.ibm.com> wrote:
> 
> > > Further, we need to think how we're going to do PQC support in IMA -
> > > particularly as the signatures are so much bigger and verification slower.
> > 
> > Perhaps, but these same reasons would apply to kernel modules, firmware, and
> > the kernel image.  Why would IMA be special?!
> 
> Scale.  I wouldn't expect more than a couple of hundred or so kernel module
> and firmware signatures - and, for the most part, that would be done once
> during boot.  On the other hand, I'm assuming that a lot more IMA signatures
> might need checking and maybe more frequently.

Similarly, most file signatures would be verified on boot and the results cached
to limit the performance impact.  The number of file signatures needing to be
verified is based on policy.

Mimi

^ permalink raw reply

* Re: IMA and PQC
From: David Howells @ 2026-01-26 21:36 UTC (permalink / raw)
  To: Mimi Zohar
  Cc: dhowells, Simo Sorce, Roberto Sassu, Dmitry Kasatkin,
	Eric Snowberg, Eric Biggers, linux-integrity, linux-crypto,
	keyrings, linux-modules, linux-kernel
In-Reply-To: <821cb2becf70b2dcb903e74685643f8b60a5cbb6.camel@linux.ibm.com>

Mimi Zohar <zohar@linux.ibm.com> wrote:

> > Further, we need to think how we're going to do PQC support in IMA -
> > particularly as the signatures are so much bigger and verification slower.
> 
> Perhaps, but these same reasons would apply to kernel modules, firmware, and
> the kernel image.  Why would IMA be special?!

Scale.  I wouldn't expect more than a couple of hundred or so kernel module
and firmware signatures - and, for the most part, that would be done once
during boot.  On the other hand, I'm assuming that a lot more IMA signatures
might need checking and maybe more frequently.

David


^ permalink raw reply

* Re: IMA and PQC
From: Mimi Zohar @ 2026-01-26 21:04 UTC (permalink / raw)
  To: David Howells
  Cc: Simo Sorce, Roberto Sassu, Dmitry Kasatkin, Eric Snowberg,
	Eric Biggers, linux-integrity, linux-crypto, keyrings,
	linux-modules, linux-kernel
In-Reply-To: <1783975.1769190197@warthog.procyon.org.uk>

On Fri, 2026-01-23 at 17:43 +0000, David Howells wrote:
> Hi Mimi,
> 
> I've posted patches which I hope will accepted to implement ML-DSA module
> signing:
> 
> 	https://lore.kernel.org/linux-crypto/1753972.1769166821@warthog.procyon.org.uk/T/#t
> 
> but for the moment, it will give an error to pkcs7_get_digest() if there's no
> digest available (which there won't be with ML-DSA).  This means that there
> isn't a hash for IMA to get at for TPM measurement.

IMA calculates the file hash for three different purposes: augment the audit
log, extend the TPM, and of course verify the file data signature.

From what I gather there is ML-DSA pure and pre-hash modes.  What you've
implemented is ML-DSA pure mode which passes the data in order to calculate the
file hash, not ML-DSA pre-hash.  For this reason, there is no option to use the
file hash.

> 
> Now, I probably have to make a SHA256 hash anyway for UEFI blacklisting
> purposes, so that could be used.  Alternatively, we can require the use of
> authenticatedAttributes/signedAttrs and give you the hash of that - but then
> you're a bit at the mercy of whatever hashes were used.

Let's discuss alternatives and not jump to the conclusion that you have to break
IMA.

> 
> Further, we need to think how we're going to do PQC support in IMA -
> particularly as the signatures are so much bigger and verification slower.

Perhaps, but these same reasons would apply to kernel modules, firmware, and the
kernel image.  Why would IMA be special?!

> 
> Would ML-DSA-44 be acceptable?  Should we grab some internal state out of
> ML-DSA to use in lieu of a hash?

Is ML-DSA-44 acceptable for kernel modules, firmware, or the kernel image?

Mimi


^ permalink raw reply

* [ANN] Linux Security Summit 2026 CfP
From: James Morris @ 2026-01-26 20:58 UTC (permalink / raw)
  To: linux-security-module
  Cc: Linux Security Summit Program Committee, linux-kernel,
	kernel-hardening, linux-integrity, lwn, linux-crypto, keyrings

=============================================================================
                   ANNOUNCEMENT AND CALL FOR PARTICIPATION

                   LINUX SECURITY SUMMIT NORTH AMERICA 2026
                             
                                  May 21-22
                             Minneapolis, MN, USA
==============================================================================

DESCRIPTION
 
Linux Security Summit North America (LSS-NA) 2026 is a technical forum for
collaboration between Linux developers, researchers, and end-users.

Its primary aim is to foster community efforts in deeply analyzing and
solving Linux operating system security challenges, including those in the
Linux kernel.

Proposals should be submitted via:
    https://events.linuxfoundation.org/linux-security-summit-north-america/

SUGGESTED TOPICS

    * Access Control
    * Case Studies
    * Cryptography and Key Management
    * Emerging Technologies, Threats & Techniques
    * Hardware Security
    * IoT and Embedded Security
    * Integrity Policy and Enforcement
    * Open Source Supply Chain for the Linux OS
    * Security Tools
    * Security UX
    * Linux OS Hardening
    * Virtualization and Containers

DATES TO REMEMBER:

    * CFP Close: Sunday, March 15 at 11:59 PM CDT
    * CFP Notifications: Tuesday, March 31
    * Schedule Announced: Thursday, April 2
    * Event Date: Thursday, May 21 - Friday, May 22

WHO SHOULD ATTEND
 
We're seeking a diverse range of attendees and welcome participation by
people involved in Linux security development, operations, and research.
 
LSS is a unique global event that provides the opportunity to present and
discuss your work or research with key Linux security community members and
maintainers.  It's also useful for those who wish to keep up with the latest
in Linux security development and to provide input to the development
process.

MASTODON

  For event updates and announcements, follow:
    
    https://social.kernel.org/LinuxSecSummit
  
  #linuxsecuritysummit

PROGRAM COMMITTEE

  The program committee for LSS 2026 is:

    * James Morris, Microsoft
    * Serge Hallyn, Geico
    * Paul Moore, Microsoft
    * Stephen Smalley, NSA
    * Elena Reshetova, Intel
    * John Johansen, Canonical
    * Kees Cook, Google
    * Casey Schaufler
    * Mimi Zohar, IBM
    * David A. Wheeler, Linux Foundation

  The program committee may be contacted as a group via email:
    lss-pc () lists.linuxfoundation.org


^ permalink raw reply

* Re: [GIT PULL] KEYS: trusted: keys-trusted-next-6.19-rc7
From: pr-tracker-bot @ 2026-01-25 20:21 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: Linus Torvalds, David Howells, James Bottomley, Mimi Zohar,
	keyrings, linux-integrity, linux-security-module
In-Reply-To: <aXZPW1HnC0kM-VDC@kernel.org>

The pull request you sent on Sun, 25 Jan 2026 19:14:03 +0200:

> git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git tags/keys-trusted-next-6.19-rc7

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/f9e6e6d210669f24697e615b68b5abbae9d7a32e

Thank you!

-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/prtracker.html

^ permalink raw reply

* [PATCH v9 11/11] tpm-buf: Implement managed allocations
From: Jarkko Sakkinen @ 2026-01-25 19:25 UTC (permalink / raw)
  To: linux-integrity
  Cc: Jarkko Sakkinen, Ross Philipson, Stefan Berger, James Bottomley,
	Jarkko Sakkinen, Mimi Zohar, David Howells, Paul Moore,
	James Morris, Serge E. Hallyn, open list:KEYS-TRUSTED,
	open list:SECURITY SUBSYSTEM, open list
In-Reply-To: <20260125192526.782202-1-jarkko@kernel.org>

From: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>

Decouple kzalloc from buffer creation, so that a managed allocation can be
used:

	struct tpm_buf *buf __free(kfree) buf = kzalloc(TPM_BUFSIZE,
							GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	tpm_buf_init(buf, TPM_BUFSIZE);

Alternatively, stack allocations are also possible:

	u8 buf_data[512];
	struct tpm_buf *buf = (struct tpm_buf *)buf_data;
	tpm_buf_init(buf, sizeof(buf_data));

This is achieved by embedding buffer's header inside the allocated blob,
instead of having an outer wrapper.

Cc: Ross Philipson <ross.philipson@oracle.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
---
 drivers/char/tpm/tpm-buf.c                | 123 +++++----
 drivers/char/tpm/tpm-sysfs.c              |  21 +-
 drivers/char/tpm/tpm.h                    |   1 -
 drivers/char/tpm/tpm1-cmd.c               | 163 +++++-------
 drivers/char/tpm/tpm2-cmd.c               | 298 ++++++++++------------
 drivers/char/tpm/tpm2-sessions.c          | 142 +++++------
 drivers/char/tpm/tpm2-space.c             |  44 ++--
 drivers/char/tpm/tpm_vtpm_proxy.c         |  30 +--
 include/linux/tpm.h                       |  20 +-
 security/keys/trusted-keys/trusted_tpm1.c |  36 +--
 security/keys/trusted-keys/trusted_tpm2.c | 173 ++++++-------
 11 files changed, 499 insertions(+), 552 deletions(-)

diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index 11b6bcf2f43d..042da92f94e1 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -7,81 +7,107 @@
 #include <linux/module.h>
 #include <linux/tpm.h>
 
-/**
- * tpm_buf_init() - Allocate and initialize a TPM command
- * @buf:	A &tpm_buf
- * @tag:	TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS
- * @ordinal:	A command ordinal
- *
- * Return: 0 or -ENOMEM
- */
-int tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal)
+static void __tpm_buf_size_invariant(struct tpm_buf *buf, u16 buf_size)
 {
-	buf->data = (u8 *)__get_free_page(GFP_KERNEL);
-	if (!buf->data)
-		return -ENOMEM;
-
-	tpm_buf_reset(buf, tag, ordinal);
-	return 0;
+	u32 buf_size_2 = (u32)buf->capacity + (u32)sizeof(*buf);
+
+	if (!buf->capacity) {
+		if (buf_size > TPM_BUFSIZE) {
+			WARN(1, "%s: size overflow: %u\n", __func__, buf_size);
+			buf->flags |= TPM_BUF_INVALID;
+		}
+	} else {
+		if (buf_size != buf_size_2) {
+			WARN(1, "%s: size mismatch: %u != %u\n", __func__, buf_size,
+			     buf_size_2);
+			buf->flags |= TPM_BUF_INVALID;
+		}
+	}
 }
-EXPORT_SYMBOL_GPL(tpm_buf_init);
 
-/**
- * tpm_buf_reset() - Initialize a TPM command
- * @buf:	A &tpm_buf
- * @tag:	TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS
- * @ordinal:	A command ordinal
- */
-void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal)
+static void __tpm_buf_reset(struct tpm_buf *buf, u16 buf_size, u16 tag, u32 ordinal)
 {
 	struct tpm_header *head = (struct tpm_header *)buf->data;
 
+	__tpm_buf_size_invariant(buf, buf_size);
+
+	if (buf->flags & TPM_BUF_INVALID)
+		return;
+
 	WARN_ON(tag != TPM_TAG_RQU_COMMAND && tag != TPM2_ST_NO_SESSIONS &&
 		tag != TPM2_ST_SESSIONS && tag != 0);
 
 	buf->flags = 0;
 	buf->length = sizeof(*head);
+	buf->capacity = buf_size - sizeof(*buf);
 	head->tag = cpu_to_be16(tag);
 	head->length = cpu_to_be32(sizeof(*head));
 	head->ordinal = cpu_to_be32(ordinal);
 }
-EXPORT_SYMBOL_GPL(tpm_buf_reset);
+
+static void __tpm_buf_reset_sized(struct tpm_buf *buf, u16 buf_size)
+{
+	__tpm_buf_size_invariant(buf, buf_size);
+
+	if (buf->flags & TPM_BUF_INVALID)
+		return;
+
+	buf->flags = TPM_BUF_TPM2B;
+	buf->length = 2;
+	buf->capacity = buf_size - sizeof(*buf);
+	buf->data[0] = 0;
+	buf->data[1] = 0;
+}
 
 /**
- * tpm_buf_init_sized() - Allocate and initialize a sized (TPM2B) buffer
- * @buf:	A @tpm_buf
- *
- * Return: 0 or -ENOMEM
+ * tpm_buf_init() - Initialize a TPM command
+ * @buf:	A &tpm_buf
+ * @buf_size:	Size of the buffer.
  */
-int tpm_buf_init_sized(struct tpm_buf *buf)
+void tpm_buf_init(struct tpm_buf *buf, u16 buf_size)
 {
-	buf->data = (u8 *)__get_free_page(GFP_KERNEL);
-	if (!buf->data)
-		return -ENOMEM;
+	memset(buf, 0, buf_size);
+	__tpm_buf_reset(buf, buf_size, TPM_TAG_RQU_COMMAND, 0);
+}
+EXPORT_SYMBOL_GPL(tpm_buf_init);
 
-	tpm_buf_reset_sized(buf);
-	return 0;
+/**
+ * tpm_buf_init_sized() - Initialize a sized buffer
+ * @buf:	A &tpm_buf
+ * @buf_size:	Size of the buffer.
+ */
+void tpm_buf_init_sized(struct tpm_buf *buf, u16 buf_size)
+{
+	memset(buf, 0, buf_size);
+	__tpm_buf_reset_sized(buf, buf_size);
 }
 EXPORT_SYMBOL_GPL(tpm_buf_init_sized);
 
 /**
- * tpm_buf_reset_sized() - Initialize a sized buffer
+ * tpm_buf_reset() - Re-initialize a TPM command
  * @buf:	A &tpm_buf
+ * @tag:	TPM_TAG_RQU_COMMAND, TPM2_ST_NO_SESSIONS or TPM2_ST_SESSIONS
+ * @ordinal:	A command ordinal
  */
-void tpm_buf_reset_sized(struct tpm_buf *buf)
+void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal)
 {
-	buf->flags = TPM_BUF_TPM2B;
-	buf->length = 2;
-	buf->data[0] = 0;
-	buf->data[1] = 0;
+	u16 buf_size = buf->capacity + sizeof(*buf);
+
+	__tpm_buf_reset(buf, buf_size, tag, ordinal);
 }
-EXPORT_SYMBOL_GPL(tpm_buf_reset_sized);
+EXPORT_SYMBOL_GPL(tpm_buf_reset);
 
-void tpm_buf_destroy(struct tpm_buf *buf)
+/**
+ * tpm_buf_reset_sized() - Re-initialize a sized buffer
+ * @buf:	A &tpm_buf
+ */
+void tpm_buf_reset_sized(struct tpm_buf *buf)
 {
-	free_page((unsigned long)buf->data);
+	u16 buf_size = buf->capacity + sizeof(*buf);
+
+	__tpm_buf_reset_sized(buf, buf_size);
 }
-EXPORT_SYMBOL_GPL(tpm_buf_destroy);
+EXPORT_SYMBOL_GPL(tpm_buf_reset_sized);
 
 /**
  * tpm_buf_length() - Return the number of bytes consumed by the data
@@ -89,8 +115,11 @@ EXPORT_SYMBOL_GPL(tpm_buf_destroy);
  *
  * Return: The number of bytes consumed by the buffer
  */
-u32 tpm_buf_length(struct tpm_buf *buf)
+u16 tpm_buf_length(struct tpm_buf *buf)
 {
+	if (buf->flags & TPM_BUF_INVALID)
+		return 0;
+
 	return buf->length;
 }
 EXPORT_SYMBOL_GPL(tpm_buf_length);
@@ -103,10 +132,12 @@ EXPORT_SYMBOL_GPL(tpm_buf_length);
  */
 void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length)
 {
+	u32 total_length = (u32)buf->length + (u32)new_length;
+
 	if (buf->flags & TPM_BUF_INVALID)
 		return;
 
-	if ((buf->length + new_length) > PAGE_SIZE) {
+	if (total_length > (u32)buf->capacity) {
 		WARN(1, "tpm_buf: write overflow\n");
 		buf->flags |= TPM_BUF_INVALID;
 		return;
diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 4a6a27ee295d..0f321c307bc6 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -32,28 +32,29 @@ struct tpm_readpubek_out {
 static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
-	struct tpm_buf tpm_buf;
 	struct tpm_readpubek_out *out;
 	int i;
 	char *str = buf;
 	struct tpm_chip *chip = to_tpm_chip(dev);
 	char anti_replay[20];
 
+	struct tpm_buf *tpm_buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!tpm_buf)
+		return -ENOMEM;
+
 	memset(&anti_replay, 0, sizeof(anti_replay));
 
 	if (tpm_try_get_ops(chip))
 		return 0;
 
-	if (tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK))
-		goto out_ops;
-
-	tpm_buf_append(&tpm_buf, anti_replay, sizeof(anti_replay));
+	tpm_buf_init(tpm_buf, TPM_BUFSIZE);
+	tpm_buf_reset(tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK);
+	tpm_buf_append(tpm_buf, anti_replay, sizeof(anti_replay));
 
-	if (tpm_transmit_cmd(chip, &tpm_buf, READ_PUBEK_RESULT_MIN_BODY_SIZE,
-			     "attempting to read the PUBEK"))
-		goto out_buf;
+	if (tpm_transmit_cmd(chip, tpm_buf, READ_PUBEK_RESULT_MIN_BODY_SIZE, "TPM_ReadPubek"))
+		goto out_ops;
 
-	out = (struct tpm_readpubek_out *)&tpm_buf.data[10];
+	out = (struct tpm_readpubek_out *)&tpm_buf->data[10];
 	str +=
 	    sprintf(str,
 		    "Algorithm: %4ph\n"
@@ -71,8 +72,6 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
 	for (i = 0; i < 256; i += 16)
 		str += sprintf(str, "%16ph\n", &out->modulus[i]);
 
-out_buf:
-	tpm_buf_destroy(&tpm_buf);
 out_ops:
 	tpm_put_ops(chip);
 	return str - buf;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 02c07fef41ba..5395927c62fc 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -32,7 +32,6 @@
 #endif
 
 #define TPM_MINOR		224	/* officially assigned */
-#define TPM_BUFSIZE		4096
 #define TPM_NUM_DEVICES		65536
 #define TPM_RETRY		50
 
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 3fe94f596f97..a04abe13a764 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -323,20 +323,14 @@ unsigned long tpm1_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
  */
 static int tpm1_startup(struct tpm_chip *chip)
 {
-	struct tpm_buf buf;
-	int rc;
-
-	dev_info(&chip->dev, "starting up the TPM manually\n");
-
-	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_STARTUP);
-	if (rc < 0)
-		return rc;
-
-	tpm_buf_append_u16(&buf, TPM_ST_CLEAR);
-
-	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to start the TPM");
-	tpm_buf_destroy(&buf);
-	return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_STARTUP);
+	tpm_buf_append_u16(buf, TPM_ST_CLEAR);
+	return tpm_transmit_cmd(chip, buf, 0, "TPM_Startup");
 }
 
 int tpm1_get_timeouts(struct tpm_chip *chip)
@@ -463,50 +457,47 @@ int tpm1_get_timeouts(struct tpm_chip *chip)
 int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
 		    const char *log_msg)
 {
-	struct tpm_buf buf;
-	int rc;
-
-	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_PCR_EXTEND);
-	if (rc)
-		return rc;
-
-	tpm_buf_append_u32(&buf, pcr_idx);
-	tpm_buf_append(&buf, hash, TPM_DIGEST_SIZE);
-
-	rc = tpm_transmit_cmd(chip, &buf, TPM_DIGEST_SIZE, log_msg);
-	tpm_buf_destroy(&buf);
-	return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_PCR_EXTEND);
+	tpm_buf_append_u32(buf, pcr_idx);
+	tpm_buf_append(buf, hash, TPM_DIGEST_SIZE);
+	return tpm_transmit_cmd(chip, buf, TPM_DIGEST_SIZE, log_msg);
 }
 
 #define TPM_ORD_GET_CAP 101
 ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
 		    const char *desc, size_t min_cap_length)
 {
-	struct tpm_buf buf;
 	int rc;
 
-	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_GET_CAP);
-	if (rc)
-		return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_GET_CAP);
 
 	if (subcap_id == TPM_CAP_VERSION_1_1 ||
 	    subcap_id == TPM_CAP_VERSION_1_2) {
-		tpm_buf_append_u32(&buf, subcap_id);
-		tpm_buf_append_u32(&buf, 0);
+		tpm_buf_append_u32(buf, subcap_id);
+		tpm_buf_append_u32(buf, 0);
 	} else {
 		if (subcap_id == TPM_CAP_FLAG_PERM ||
 		    subcap_id == TPM_CAP_FLAG_VOL)
-			tpm_buf_append_u32(&buf, TPM_CAP_FLAG);
+			tpm_buf_append_u32(buf, TPM_CAP_FLAG);
 		else
-			tpm_buf_append_u32(&buf, TPM_CAP_PROP);
+			tpm_buf_append_u32(buf, TPM_CAP_PROP);
 
-		tpm_buf_append_u32(&buf, 4);
-		tpm_buf_append_u32(&buf, subcap_id);
+		tpm_buf_append_u32(buf, 4);
+		tpm_buf_append_u32(buf, subcap_id);
 	}
-	rc = tpm_transmit_cmd(chip, &buf, min_cap_length, desc);
+	rc = tpm_transmit_cmd(chip, buf, min_cap_length, desc);
 	if (!rc)
-		*cap = *(cap_t *)&buf.data[TPM_HEADER_SIZE + 4];
-	tpm_buf_destroy(&buf);
+		*cap = *(cap_t *)&buf->data[TPM_HEADER_SIZE + 4];
 	return rc;
 }
 EXPORT_SYMBOL_GPL(tpm1_getcap);
@@ -526,74 +517,61 @@ struct tpm1_get_random_out {
 int tpm1_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 {
 	struct tpm1_get_random_out *resp;
-	struct tpm_buf buf;
 	u32 recd;
 	int rc;
 
 	if (!dest || !max || max > TPM_MAX_RNG_DATA)
 		return -EINVAL;
 
-	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_GET_RANDOM);
-	if (rc)
-		return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
-	tpm_buf_append_u32(&buf, max);
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_GET_RANDOM);
+	tpm_buf_append_u32(buf, max);
 
-	rc = tpm_transmit_cmd(chip, &buf, sizeof(resp->rng_data_len), "TPM_GetRandom");
+	rc = tpm_transmit_cmd(chip, buf, sizeof(resp->rng_data_len), "TPM_GetRandom");
 	if (rc) {
 		if (rc > 0)
 			rc = -EIO;
-		goto out;
+		return rc;
 	}
 
-	resp = (struct tpm1_get_random_out *)&buf.data[TPM_HEADER_SIZE];
+	resp = (struct tpm1_get_random_out *)&buf->data[TPM_HEADER_SIZE];
 
 	recd = be32_to_cpu(resp->rng_data_len);
-	if (recd > max) {
-		rc = -EIO;
-		goto out;
-	}
+	if (recd > max)
+		return -EIO;
 
-	if (buf.length < TPM_HEADER_SIZE + sizeof(resp->rng_data_len) + recd) {
-		rc = -EIO;
-		goto out;
-	}
+	if (buf->length < TPM_HEADER_SIZE + sizeof(resp->rng_data_len) + recd)
+		return -EIO;
 
 	memcpy(dest, resp->rng_data, recd);
-	tpm_buf_destroy(&buf);
 	return recd;
-
-out:
-	tpm_buf_destroy(&buf);
-	return rc;
 }
 
 #define TPM_ORD_PCRREAD 21
 int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
 {
-	struct tpm_buf buf;
 	int rc;
 
-	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_PCRREAD);
-	if (rc)
-		return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
-	tpm_buf_append_u32(&buf, pcr_idx);
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_PCRREAD);
+	tpm_buf_append_u32(buf, pcr_idx);
 
-	rc = tpm_transmit_cmd(chip, &buf, TPM_DIGEST_SIZE,
-			      "attempting to read a pcr value");
+	rc = tpm_transmit_cmd(chip, buf, TPM_DIGEST_SIZE, "TPM_PCRRead");
 	if (rc)
-		goto out;
-
-	if (tpm_buf_length(&buf) < TPM_DIGEST_SIZE) {
-		rc = -EFAULT;
-		goto out;
-	}
+		return rc;
 
-	memcpy(res_buf, &buf.data[TPM_HEADER_SIZE], TPM_DIGEST_SIZE);
+	if (buf->length < TPM_DIGEST_SIZE)
+		return -EFAULT;
 
-out:
-	tpm_buf_destroy(&buf);
+	memcpy(res_buf, &buf->data[TPM_HEADER_SIZE], TPM_DIGEST_SIZE);
 	return rc;
 }
 
@@ -607,16 +585,13 @@ int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
  */
 static int tpm1_continue_selftest(struct tpm_chip *chip)
 {
-	struct tpm_buf buf;
-	int rc;
-
-	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_CONTINUE_SELFTEST);
-	if (rc)
-		return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
-	rc = tpm_transmit_cmd(chip, &buf, 0, "continue selftest");
-	tpm_buf_destroy(&buf);
-	return rc;
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_CONTINUE_SELFTEST);
+	return tpm_transmit_cmd(chip, buf, 0, "TPM_ContinueSelfTest");
 }
 
 /**
@@ -730,22 +705,24 @@ int tpm1_auto_startup(struct tpm_chip *chip)
 int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr)
 {
 	u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
-	struct tpm_buf buf;
 	unsigned int try;
 	int rc;
 
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
 	/* for buggy tpm, flush pcrs with extend to selected dummy */
 	if (tpm_suspend_pcr)
 		rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, dummy_hash,
 				     "extending dummy pcr before suspend");
 
-	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_SAVESTATE);
-	if (rc)
-		return rc;
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_SAVESTATE);
+
 	/* now do the actual savestate */
 	for (try = 0; try < TPM_RETRY; try++) {
-		rc = tpm_transmit_cmd(chip, &buf, 0, NULL);
+		rc = tpm_transmit_cmd(chip, buf, 0, NULL);
 		/*
 		 * If the TPM indicates that it is too busy to respond to
 		 * this command then retry before giving up.  It can take
@@ -760,7 +737,7 @@ int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr)
 			break;
 		tpm_msleep(TPM_TIMEOUT_RETRY);
 
-		tpm_buf_reset(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_SAVESTATE);
+		tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_SAVESTATE);
 	}
 
 	if (rc)
@@ -770,8 +747,6 @@ int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr)
 		dev_warn(&chip->dev, "TPM savestate took %dms\n",
 			 try * TPM_TIMEOUT_RETRY);
 
-	tpm_buf_destroy(&buf);
-
 	return rc;
 }
 
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 39ef6b7a0fbc..7455c492fc66 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -119,12 +119,15 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 {
 	int i;
 	int rc;
-	struct tpm_buf buf;
 	struct tpm2_pcr_read_out *out;
 	u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0};
 	u16 digest_size;
 	u16 expected_digest_size = 0;
 
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
 	if (pcr_idx >= TPM2_PLATFORM_PCR)
 		return -EINVAL;
 
@@ -139,36 +142,31 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 		expected_digest_size = chip->allocated_banks[i].digest_size;
 	}
 
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ);
-	if (rc)
-		return rc;
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ);
 
 	pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
 
-	tpm_buf_append_u32(&buf, 1);
-	tpm_buf_append_u16(&buf, digest->alg_id);
-	tpm_buf_append_u8(&buf, TPM2_PCR_SELECT_MIN);
-	tpm_buf_append(&buf, (const unsigned char *)pcr_select,
+	tpm_buf_append_u32(buf, 1);
+	tpm_buf_append_u16(buf, digest->alg_id);
+	tpm_buf_append_u8(buf, TPM2_PCR_SELECT_MIN);
+	tpm_buf_append(buf, (const unsigned char *)pcr_select,
 		       sizeof(pcr_select));
 
-	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to read a pcr value");
+	rc = tpm_transmit_cmd(chip, buf, 0, "TPM2_PCR_Read");
 	if (rc)
-		goto out;
+		return rc;
 
-	out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
+	out = (struct tpm2_pcr_read_out *)&buf->data[TPM_HEADER_SIZE];
 	digest_size = be16_to_cpu(out->digest_size);
 	if (digest_size > sizeof(digest->digest) ||
-	    (!digest_size_ptr && digest_size != expected_digest_size)) {
-		rc = -EINVAL;
-		goto out;
-	}
+	    (!digest_size_ptr && digest_size != expected_digest_size))
+		return -EINVAL;
 
 	if (digest_size_ptr)
 		*digest_size_ptr = digest_size;
 
 	memcpy(digest->digest, out->digest, digest_size);
-out:
-	tpm_buf_destroy(&buf);
 	return rc;
 }
 
@@ -184,57 +182,53 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 		    struct tpm_digest *digests)
 {
-	struct tpm_buf buf;
 	int rc;
 	int i;
 
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
 	if (!disable_pcr_integrity) {
 		rc = tpm2_start_auth_session(chip);
 		if (rc)
 			return rc;
 	}
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
-	if (rc) {
-		if (!disable_pcr_integrity)
-			tpm2_end_auth_session(chip);
-		return rc;
-	}
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
 
 	if (!disable_pcr_integrity) {
-		rc = tpm_buf_append_name(chip, &buf, pcr_idx, (u8 *)&pcr_idx,
+		rc = tpm_buf_append_name(chip, buf, pcr_idx, (u8 *)&pcr_idx,
 					 sizeof(u32));
-		if (rc) {
-			tpm_buf_destroy(&buf);
+		if (rc)
 			return rc;
-		}
-		tpm_buf_append_hmac_session(chip, &buf, 0, NULL, 0);
+		tpm_buf_append_hmac_session(chip, buf, 0, NULL, 0);
 	} else {
-		tpm_buf_append_u32(&buf, pcr_idx);
-		tpm_buf_append_auth(chip, &buf, NULL, 0);
+		tpm_buf_append_u32(buf, pcr_idx);
+		tpm_buf_append_auth(chip, buf, NULL, 0);
 	}
 
-	tpm_buf_append_u32(&buf, chip->nr_allocated_banks);
+	tpm_buf_append_u32(buf, chip->nr_allocated_banks);
 
 	for (i = 0; i < chip->nr_allocated_banks; i++) {
-		tpm_buf_append_u16(&buf, digests[i].alg_id);
-		tpm_buf_append(&buf, (const unsigned char *)&digests[i].digest,
+		tpm_buf_append_u16(buf, digests[i].alg_id);
+		tpm_buf_append(buf, (const unsigned char *)&digests[i].digest,
 			       chip->allocated_banks[i].digest_size);
 	}
+	if (buf->flags & TPM_BUF_INVALID)
+		return -EINVAL;
 
 	if (!disable_pcr_integrity) {
-		rc = tpm_buf_fill_hmac_session(chip, &buf);
-		if (rc) {
-			tpm_buf_destroy(&buf);
+		rc = tpm_buf_fill_hmac_session(chip, buf);
+		if (rc)
 			return rc;
-		}
 	}
 
-	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting extend a PCR value");
-	if (!disable_pcr_integrity)
-		rc = tpm_buf_check_hmac_response(chip, &buf, rc);
+	rc = tpm_transmit_cmd(chip, buf, 0, "TPM2_PCR_Extend");
 
-	tpm_buf_destroy(&buf);
+	if (!disable_pcr_integrity)
+		rc = tpm_buf_check_hmac_response(chip, buf, rc);
 
 	return rc;
 }
@@ -254,7 +248,6 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 {
 	struct tpm2_get_random_out *resp;
 	struct tpm_header *head;
-	struct tpm_buf buf;
 	off_t offset;
 	u32 recd;
 	int err;
@@ -266,32 +259,32 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 	if (err)
 		return err;
 
-	err = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_GET_RANDOM);
-	if (err) {
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf) {
 		tpm2_end_auth_session(chip);
-		return err;
+		return -ENOMEM;
 	}
 
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_GET_RANDOM);
 	if (tpm2_chip_auth(chip)) {
-		tpm_buf_append_hmac_session(chip, &buf,
+		tpm_buf_append_hmac_session(chip, buf,
 					    TPM2_SA_ENCRYPT | TPM2_SA_CONTINUE_SESSION,
 					    NULL, 0);
 	} else  {
-		head = (struct tpm_header *)buf.data;
+		head = (struct tpm_header *)buf->data;
 		head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
 	}
-	tpm_buf_append_u16(&buf, max);
+	tpm_buf_append_u16(buf, max);
 
-	err = tpm_buf_fill_hmac_session(chip, &buf);
-	if (err) {
-		tpm_buf_destroy(&buf);
+	err = tpm_buf_fill_hmac_session(chip, buf);
+	if (err)
 		return err;
-	}
 
-	err = tpm_transmit_cmd(chip, &buf, offsetof(struct tpm2_get_random_out, buffer),
+	err = tpm_transmit_cmd(chip, buf, offsetof(struct tpm2_get_random_out, buffer),
 			       "TPM2_GetRandom");
 
-	err = tpm_buf_check_hmac_response(chip, &buf, err);
+	err = tpm_buf_check_hmac_response(chip, buf, err);
 	if (err) {
 		if (err > 0)
 			err = -EIO;
@@ -299,17 +292,17 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 		goto out;
 	}
 
-	head = (struct tpm_header *)buf.data;
+	head = (struct tpm_header *)buf->data;
 	offset = TPM_HEADER_SIZE;
 
 	/* Skip the parameter size field: */
 	if (be16_to_cpu(head->tag) == TPM2_ST_SESSIONS)
 		offset += 4;
 
-	resp = (struct tpm2_get_random_out *)&buf.data[offset];
+	resp = (struct tpm2_get_random_out *)&buf->data[offset];
 	recd = min_t(u32, be16_to_cpu(resp->size), max);
 
-	if (tpm_buf_length(&buf) <
+	if (tpm_buf_length(buf) <
 	    TPM_HEADER_SIZE + offsetof(struct tpm2_get_random_out, buffer) + recd) {
 		err = -EIO;
 		goto out;
@@ -319,7 +312,6 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 	return recd;
 
 out:
-	tpm_buf_destroy(&buf);
 	tpm2_end_auth_session(chip);
 	return err;
 }
@@ -331,20 +323,18 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
  */
 void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
 {
-	struct tpm_buf buf;
-	int rc;
-
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT);
-	if (rc) {
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf) {
 		dev_warn(&chip->dev, "0x%08x was not flushed, out of memory\n",
 			 handle);
 		return;
 	}
 
-	tpm_buf_append_u32(&buf, handle);
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT);
+	tpm_buf_append_u32(buf, handle);
 
-	tpm_transmit_cmd(chip, &buf, 0, "flushing context");
-	tpm_buf_destroy(&buf);
+	tpm_transmit_cmd(chip, buf, 0, "TPM2_FlushContext");
 }
 EXPORT_SYMBOL_GPL(tpm2_flush_context);
 
@@ -371,19 +361,20 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
 			const char *desc)
 {
 	struct tpm2_get_cap_out *out;
-	struct tpm_buf buf;
 	int rc;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
-	if (rc)
-		return rc;
-	tpm_buf_append_u32(&buf, TPM2_CAP_TPM_PROPERTIES);
-	tpm_buf_append_u32(&buf, property_id);
-	tpm_buf_append_u32(&buf, 1);
-	rc = tpm_transmit_cmd(chip, &buf, 0, NULL);
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
+	tpm_buf_append_u32(buf, TPM2_CAP_TPM_PROPERTIES);
+	tpm_buf_append_u32(buf, property_id);
+	tpm_buf_append_u32(buf, 1);
+	rc = tpm_transmit_cmd(chip, buf, 0, NULL);
 	if (!rc) {
-		out = (struct tpm2_get_cap_out *)
-			&buf.data[TPM_HEADER_SIZE];
+		out = (struct tpm2_get_cap_out *)&buf->data[TPM_HEADER_SIZE];
 		/*
 		 * To prevent failing boot up of some systems, Infineon TPM2.0
 		 * returns SUCCESS on TPM2_Startup in field upgrade mode. Also
@@ -395,7 +386,6 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
 		else
 			rc = -ENODATA;
 	}
-	tpm_buf_destroy(&buf);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(tpm2_get_tpm_pt);
@@ -412,15 +402,14 @@ EXPORT_SYMBOL_GPL(tpm2_get_tpm_pt);
  */
 void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
 {
-	struct tpm_buf buf;
-	int rc;
-
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SHUTDOWN);
-	if (rc)
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
 		return;
-	tpm_buf_append_u16(&buf, shutdown_type);
-	tpm_transmit_cmd(chip, &buf, 0, "stopping the TPM");
-	tpm_buf_destroy(&buf);
+
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SHUTDOWN);
+	tpm_buf_append_u16(buf, shutdown_type);
+	tpm_transmit_cmd(chip, buf, 0, "TPM2_Shutdown");
 }
 
 /**
@@ -438,20 +427,19 @@ void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
  */
 static int tpm2_do_selftest(struct tpm_chip *chip)
 {
-	struct tpm_buf buf;
 	int full;
 	int rc;
 
-	for (full = 0; full < 2; full++) {
-		rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SELF_TEST);
-		if (rc)
-			return rc;
-
-		tpm_buf_append_u8(&buf, full);
-		rc = tpm_transmit_cmd(chip, &buf, 0,
-				      "attempting the self test");
-		tpm_buf_destroy(&buf);
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SELF_TEST);
+	for (full = 0; full < 2; full++) {
+		tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SELF_TEST);
+		tpm_buf_append_u8(buf, full);
+		rc = tpm_transmit_cmd(chip, buf, 0, "TPM2_SelfTest");
 		if (rc == TPM2_RC_TESTING)
 			rc = TPM2_RC_SUCCESS;
 		if (rc == TPM2_RC_INITIALIZE || rc == TPM2_RC_SUCCESS)
@@ -476,23 +464,24 @@ static int tpm2_do_selftest(struct tpm_chip *chip)
 int tpm2_probe(struct tpm_chip *chip)
 {
 	struct tpm_header *out;
-	struct tpm_buf buf;
 	int rc;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
-	if (rc)
-		return rc;
-	tpm_buf_append_u32(&buf, TPM2_CAP_TPM_PROPERTIES);
-	tpm_buf_append_u32(&buf, TPM_PT_TOTAL_COMMANDS);
-	tpm_buf_append_u32(&buf, 1);
-	rc = tpm_transmit_cmd(chip, &buf, 0, NULL);
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
+	tpm_buf_append_u32(buf, TPM2_CAP_TPM_PROPERTIES);
+	tpm_buf_append_u32(buf, TPM_PT_TOTAL_COMMANDS);
+	tpm_buf_append_u32(buf, 1);
+	rc = tpm_transmit_cmd(chip, buf, 0, NULL);
 	/* We ignore TPM return codes on purpose. */
 	if (rc >=  0) {
-		out = (struct tpm_header *)buf.data;
+		out = (struct tpm_header *)buf->data;
 		if (be16_to_cpu(out->tag) == TPM2_ST_NO_SESSIONS)
 			chip->flags |= TPM_CHIP_FLAG_TPM2;
 	}
-	tpm_buf_destroy(&buf);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(tpm2_probe);
@@ -532,7 +521,6 @@ struct tpm2_pcr_selection {
 ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 {
 	struct tpm2_pcr_selection pcr_selection;
-	struct tpm_buf buf;
 	void *marker;
 	void *end;
 	void *pcr_select_offset;
@@ -544,39 +532,37 @@ ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 	int rc;
 	int i = 0;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
-	if (rc)
-		return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
-	tpm_buf_append_u32(&buf, TPM2_CAP_PCRS);
-	tpm_buf_append_u32(&buf, 0);
-	tpm_buf_append_u32(&buf, 1);
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
+	tpm_buf_append_u32(buf, TPM2_CAP_PCRS);
+	tpm_buf_append_u32(buf, 0);
+	tpm_buf_append_u32(buf, 1);
 
-	rc = tpm_transmit_cmd(chip, &buf, 9, "get tpm pcr allocation");
+	rc = tpm_transmit_cmd(chip, buf, 9, "TPM2_GetCapability(PCRS)");
 	if (rc)
-		goto out;
+		return rc;
 
-	nr_possible_banks = be32_to_cpup(
-		(__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);
+	nr_possible_banks = be32_to_cpup((__be32 *)&buf->data[TPM_HEADER_SIZE + 5]);
 	if (nr_possible_banks > TPM2_MAX_PCR_BANKS) {
 		pr_err("tpm: out of bank capacity: %u > %u\n",
 		       nr_possible_banks, TPM2_MAX_PCR_BANKS);
-		rc = -ENOMEM;
-		goto out;
+		return -ENOMEM;
 	}
 
-	marker = &buf.data[TPM_HEADER_SIZE + 9];
+	marker = &buf->data[TPM_HEADER_SIZE + 9];
 
-	rsp_len = be32_to_cpup((__be32 *)&buf.data[2]);
-	end = &buf.data[rsp_len];
+	rsp_len = be32_to_cpup((__be32 *)&buf->data[2]);
+	end = &buf->data[rsp_len];
 
 	for (i = 0; i < nr_possible_banks; i++) {
 		pcr_select_offset = marker +
 			offsetof(struct tpm2_pcr_selection, size_of_select);
-		if (pcr_select_offset >= end) {
-			rc = -EFAULT;
-			break;
-		}
+		if (pcr_select_offset >= end)
+			return -EFAULT;
 
 		memcpy(&pcr_selection, marker, sizeof(pcr_selection));
 		hash_alg = be16_to_cpu(pcr_selection.hash_alg);
@@ -588,7 +574,7 @@ ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 
 			rc = tpm2_init_bank_info(chip, nr_alloc_banks);
 			if (rc < 0)
-				break;
+				return rc;
 
 			nr_alloc_banks++;
 		}
@@ -600,21 +586,21 @@ ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 	}
 
 	chip->nr_allocated_banks = nr_alloc_banks;
-out:
-	tpm_buf_destroy(&buf);
-
-	return rc;
+	return 0;
 }
 
 int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
 {
-	struct tpm_buf buf;
 	u32 nr_commands;
 	__be32 *attrs;
 	u32 cc;
 	int i;
 	int rc;
 
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
 	rc = tpm2_get_tpm_pt(chip, TPM_PT_TOTAL_COMMANDS, &nr_commands, NULL);
 	if (rc)
 		goto out;
@@ -631,30 +617,24 @@ int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
 		goto out;
 	}
 
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
-	if (rc)
-		goto out;
-
-	tpm_buf_append_u32(&buf, TPM2_CAP_COMMANDS);
-	tpm_buf_append_u32(&buf, TPM2_CC_FIRST);
-	tpm_buf_append_u32(&buf, nr_commands);
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
+	tpm_buf_append_u32(buf, TPM2_CAP_COMMANDS);
+	tpm_buf_append_u32(buf, TPM2_CC_FIRST);
+	tpm_buf_append_u32(buf, nr_commands);
 
-	rc = tpm_transmit_cmd(chip, &buf, 9 + 4 * nr_commands, NULL);
-	if (rc) {
-		tpm_buf_destroy(&buf);
+	rc = tpm_transmit_cmd(chip, buf, 9 + 4 * nr_commands, NULL);
+	if (rc)
 		goto out;
-	}
 
-	if (nr_commands !=
-	    be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE + 5])) {
+	if (nr_commands != be32_to_cpup((__be32 *)&buf->data[TPM_HEADER_SIZE + 5])) {
 		rc = -EFAULT;
-		tpm_buf_destroy(&buf);
 		goto out;
 	}
 
 	chip->nr_commands = nr_commands;
 
-	attrs = (__be32 *)&buf.data[TPM_HEADER_SIZE + 9];
+	attrs = (__be32 *)&buf->data[TPM_HEADER_SIZE + 9];
 	for (i = 0; i < nr_commands; i++, attrs++) {
 		chip->cc_attrs_tbl[i] = be32_to_cpup(attrs);
 		cc = chip->cc_attrs_tbl[i] & 0xFFFF;
@@ -666,8 +646,6 @@ int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
 		}
 	}
 
-	tpm_buf_destroy(&buf);
-
 out:
 	if (rc > 0)
 		rc = -ENODEV;
@@ -688,20 +666,14 @@ EXPORT_SYMBOL_GPL(tpm2_get_cc_attrs_tbl);
 
 static int tpm2_startup(struct tpm_chip *chip)
 {
-	struct tpm_buf buf;
-	int rc;
-
-	dev_info(&chip->dev, "starting up the TPM manually\n");
-
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_STARTUP);
-	if (rc < 0)
-		return rc;
-
-	tpm_buf_append_u16(&buf, TPM2_SU_CLEAR);
-	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to start the TPM");
-	tpm_buf_destroy(&buf);
-
-	return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_STARTUP);
+	tpm_buf_append_u16(buf, TPM2_SU_CLEAR);
+	return tpm_transmit_cmd(chip, buf, 0, "TPM2_Startup");
 }
 
 /**
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 016bed63a755..0926da478932 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -175,7 +175,6 @@ int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
 	u32 mso = tpm2_handle_mso(handle);
 	off_t offset = TPM_HEADER_SIZE;
 	int rc, name_size_alg;
-	struct tpm_buf buf;
 
 	if (mso != TPM2_MSO_PERSISTENT && mso != TPM2_MSO_VOLATILE &&
 	    mso != TPM2_MSO_NVRAM) {
@@ -183,47 +182,41 @@ int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
 		return sizeof(u32);
 	}
 
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_READ_PUBLIC);
-	if (rc)
-		return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
-	tpm_buf_append_u32(&buf, handle);
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_READ_PUBLIC);
+	tpm_buf_append_u32(buf, handle);
 
-	rc = tpm_transmit_cmd(chip, &buf, 0, "TPM2_ReadPublic");
-	if (rc) {
-		tpm_buf_destroy(&buf);
+	rc = tpm_transmit_cmd(chip, buf, 0, "TPM2_ReadPublic");
+	if (rc)
 		return tpm_ret_to_err(rc);
-	}
 
 	/* Skip TPMT_PUBLIC: */
-	offset += tpm_buf_read_u16(&buf, &offset);
+	offset += tpm_buf_read_u16(buf, &offset);
 
 	/*
 	 * Ensure space for the length field of TPM2B_NAME and hashAlg field of
 	 * TPMT_HA (the extra four bytes).
 	 */
-	if (offset + 4 > tpm_buf_length(&buf)) {
-		tpm_buf_destroy(&buf);
+	if (offset + 4 > tpm_buf_length(buf))
 		return -EIO;
-	}
 
-	rc = tpm_buf_read_u16(&buf, &offset);
-	name_size_alg = name_size(&buf.data[offset]);
+	rc = tpm_buf_read_u16(buf, &offset);
+	name_size_alg = name_size(&buf->data[offset]);
 
 	if (name_size_alg < 0)
 		return name_size_alg;
 
-	if (rc != name_size_alg) {
-		tpm_buf_destroy(&buf);
+	if (rc != name_size_alg)
 		return -EIO;
-	}
 
-	if (offset + rc > tpm_buf_length(&buf)) {
-		tpm_buf_destroy(&buf);
+	if (offset + rc > tpm_buf_length(buf))
 		return -EIO;
-	}
 
-	memcpy(name, &buf.data[offset], rc);
+	memcpy(name, &buf->data[offset], rc);
 	return name_size_alg;
 }
 EXPORT_SYMBOL_GPL(tpm2_read_public);
@@ -929,7 +922,6 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key)
 int tpm2_start_auth_session(struct tpm_chip *chip)
 {
 	struct tpm2_auth *auth;
-	struct tpm_buf buf;
 	u32 null_key;
 	int rc;
 
@@ -938,6 +930,10 @@ int tpm2_start_auth_session(struct tpm_chip *chip)
 		return 0;
 	}
 
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
 	auth = kzalloc(sizeof(*auth), GFP_KERNEL);
 	if (!auth)
 		return -ENOMEM;
@@ -948,41 +944,37 @@ int tpm2_start_auth_session(struct tpm_chip *chip)
 
 	auth->session = TPM_HEADER_SIZE;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_START_AUTH_SESS);
-	if (rc)
-		goto out;
-
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_START_AUTH_SESS);
 	/* salt key handle */
-	tpm_buf_append_u32(&buf, null_key);
+	tpm_buf_append_u32(buf, null_key);
 	/* bind key handle */
-	tpm_buf_append_u32(&buf, TPM2_RH_NULL);
+	tpm_buf_append_u32(buf, TPM2_RH_NULL);
 	/* nonce caller */
 	get_random_bytes(auth->our_nonce, sizeof(auth->our_nonce));
-	tpm_buf_append_u16(&buf, sizeof(auth->our_nonce));
-	tpm_buf_append(&buf, auth->our_nonce, sizeof(auth->our_nonce));
+	tpm_buf_append_u16(buf, sizeof(auth->our_nonce));
+	tpm_buf_append(buf, auth->our_nonce, sizeof(auth->our_nonce));
 
 	/* append encrypted salt and squirrel away unencrypted in auth */
-	tpm_buf_append_salt(&buf, chip, auth);
+	tpm_buf_append_salt(buf, chip, auth);
 	/* session type (HMAC, audit or policy) */
-	tpm_buf_append_u8(&buf, TPM2_SE_HMAC);
+	tpm_buf_append_u8(buf, TPM2_SE_HMAC);
 
 	/* symmetric encryption parameters */
 	/* symmetric algorithm */
-	tpm_buf_append_u16(&buf, TPM_ALG_AES);
+	tpm_buf_append_u16(buf, TPM_ALG_AES);
 	/* bits for symmetric algorithm */
-	tpm_buf_append_u16(&buf, AES_KEY_BITS);
+	tpm_buf_append_u16(buf, AES_KEY_BITS);
 	/* symmetric algorithm mode (must be CFB) */
-	tpm_buf_append_u16(&buf, TPM_ALG_CFB);
+	tpm_buf_append_u16(buf, TPM_ALG_CFB);
 	/* hash algorithm for session */
-	tpm_buf_append_u16(&buf, TPM_ALG_SHA256);
+	tpm_buf_append_u16(buf, TPM_ALG_SHA256);
 
-	rc = tpm_ret_to_err(tpm_transmit_cmd(chip, &buf, 0, "StartAuthSession"));
+	rc = tpm_ret_to_err(tpm_transmit_cmd(chip, buf, 0, "TPM2_StartAuthSession"));
 	tpm2_flush_context(chip, null_key);
 
 	if (rc == TPM2_RC_SUCCESS)
-		rc = tpm2_parse_start_auth_session(auth, &buf);
-
-	tpm_buf_destroy(&buf);
+		rc = tpm2_parse_start_auth_session(auth, buf);
 
 	if (rc == TPM2_RC_SUCCESS) {
 		chip->auth = auth;
@@ -1204,18 +1196,18 @@ static int tpm2_create_primary(struct tpm_chip *chip, u32 hierarchy,
 			       u32 *handle, u8 *name)
 {
 	int rc;
-	struct tpm_buf buf;
-	struct tpm_buf template;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE_PRIMARY);
-	if (rc)
-		return rc;
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
-	rc = tpm_buf_init_sized(&template);
-	if (rc) {
-		tpm_buf_destroy(&buf);
-		return rc;
-	}
+	struct tpm_buf *template __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!template)
+		return -ENOMEM;
+
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE_PRIMARY);
+	tpm_buf_init_sized(template, TPM_BUFSIZE);
 
 	/*
 	 * create the template.  Note: in order for userspace to
@@ -1227,75 +1219,71 @@ static int tpm2_create_primary(struct tpm_chip *chip, u32 hierarchy,
 	 */
 
 	/* key type */
-	tpm_buf_append_u16(&template, TPM_ALG_ECC);
+	tpm_buf_append_u16(template, TPM_ALG_ECC);
 
 	/* name algorithm */
-	tpm_buf_append_u16(&template, TPM_ALG_SHA256);
+	tpm_buf_append_u16(template, TPM_ALG_SHA256);
 
 	/* object properties */
-	tpm_buf_append_u32(&template, TPM2_OA_NULL_KEY);
+	tpm_buf_append_u32(template, TPM2_OA_NULL_KEY);
 
 	/* sauth policy (empty) */
-	tpm_buf_append_u16(&template, 0);
+	tpm_buf_append_u16(template, 0);
 
 	/* BEGIN parameters: key specific; for ECC*/
 
 	/* symmetric algorithm */
-	tpm_buf_append_u16(&template, TPM_ALG_AES);
+	tpm_buf_append_u16(template, TPM_ALG_AES);
 
 	/* bits for symmetric algorithm */
-	tpm_buf_append_u16(&template, AES_KEY_BITS);
+	tpm_buf_append_u16(template, AES_KEY_BITS);
 
 	/* algorithm mode (must be CFB) */
-	tpm_buf_append_u16(&template, TPM_ALG_CFB);
+	tpm_buf_append_u16(template, TPM_ALG_CFB);
 
 	/* scheme (NULL means any scheme) */
-	tpm_buf_append_u16(&template, TPM_ALG_NULL);
+	tpm_buf_append_u16(template, TPM_ALG_NULL);
 
 	/* ECC Curve ID */
-	tpm_buf_append_u16(&template, TPM2_ECC_NIST_P256);
+	tpm_buf_append_u16(template, TPM2_ECC_NIST_P256);
 
 	/* KDF Scheme */
-	tpm_buf_append_u16(&template, TPM_ALG_NULL);
+	tpm_buf_append_u16(template, TPM_ALG_NULL);
 
 	/* unique: key specific; for ECC it is two zero size points */
-	tpm_buf_append_u16(&template, 0);
-	tpm_buf_append_u16(&template, 0);
+	tpm_buf_append_u16(template, 0);
+	tpm_buf_append_u16(template, 0);
 
 	/* END parameters */
 
 	/* primary handle */
-	tpm_buf_append_u32(&buf, hierarchy);
-	tpm_buf_append_empty_auth(&buf, TPM2_RS_PW);
+	tpm_buf_append_u32(buf, hierarchy);
+	tpm_buf_append_empty_auth(buf, TPM2_RS_PW);
 
 	/* sensitive create size is 4 for two empty buffers */
-	tpm_buf_append_u16(&buf, 4);
+	tpm_buf_append_u16(buf, 4);
 
 	/* sensitive create auth data (empty) */
-	tpm_buf_append_u16(&buf, 0);
+	tpm_buf_append_u16(buf, 0);
 
 	/* sensitive create sensitive data (empty) */
-	tpm_buf_append_u16(&buf, 0);
+	tpm_buf_append_u16(buf, 0);
 
 	/* the public template */
-	tpm_buf_append(&buf, template.data, template.length);
-	tpm_buf_destroy(&template);
+	tpm_buf_append(buf, template->data, template->length);
 
 	/* outside info (empty) */
-	tpm_buf_append_u16(&buf, 0);
+	tpm_buf_append_u16(buf, 0);
 
 	/* creation PCR (none) */
-	tpm_buf_append_u32(&buf, 0);
+	tpm_buf_append_u32(buf, 0);
 
-	rc = tpm_transmit_cmd(chip, &buf, 0,
-			      "attempting to create NULL primary");
+	rc = tpm_transmit_cmd(chip, buf, 0, "TPM2_CreatePrimary");
 
 	if (rc == TPM2_RC_SUCCESS)
-		rc = tpm2_parse_create_primary(chip, &buf, handle, hierarchy,
+		rc = tpm2_parse_create_primary(chip, buf, handle, hierarchy,
 					       name);
 
-	tpm_buf_destroy(&buf);
-
 	return rc;
 }
 
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 60354cd53b5c..cbf86ff5931f 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -71,24 +71,25 @@ void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space)
 int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
 		      unsigned int *offset, u32 *handle)
 {
-	struct tpm_buf tbuf;
 	struct tpm2_context *ctx;
 	unsigned int body_size;
 	int rc;
 
-	rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_LOAD);
-	if (rc)
-		return rc;
+	struct tpm_buf *tbuf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!tbuf)
+		return -ENOMEM;
+
+	tpm_buf_init(tbuf, TPM_BUFSIZE);
+	tpm_buf_reset(tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_LOAD);
 
 	ctx = (struct tpm2_context *)&buf[*offset];
 	body_size = sizeof(*ctx) + be16_to_cpu(ctx->blob_size);
-	tpm_buf_append(&tbuf, &buf[*offset], body_size);
+	tpm_buf_append(tbuf, &buf[*offset], body_size);
 
-	rc = tpm_transmit_cmd(chip, &tbuf, 4, NULL);
+	rc = tpm_transmit_cmd(chip, tbuf, 4, NULL);
 	if (rc < 0) {
 		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
 			 __func__, rc);
-		tpm_buf_destroy(&tbuf);
 		return -EFAULT;
 	} else if (tpm2_rc_value(rc) == TPM2_RC_HANDLE ||
 		   rc == TPM2_RC_REFERENCE_H0) {
@@ -103,64 +104,55 @@ int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
 		 * flushed outside the space
 		 */
 		*handle = 0;
-		tpm_buf_destroy(&tbuf);
 		return -ENOENT;
 	} else if (tpm2_rc_value(rc) == TPM2_RC_INTEGRITY) {
-		tpm_buf_destroy(&tbuf);
 		return -EINVAL;
 	} else if (rc > 0) {
 		dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
 			 __func__, rc);
-		tpm_buf_destroy(&tbuf);
 		return -EFAULT;
 	}
 
-	*handle = be32_to_cpup((__be32 *)&tbuf.data[TPM_HEADER_SIZE]);
+	*handle = be32_to_cpup((__be32 *)&tbuf->data[TPM_HEADER_SIZE]);
 	*offset += body_size;
-
-	tpm_buf_destroy(&tbuf);
 	return 0;
 }
 
 int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
 		      unsigned int buf_size, unsigned int *offset)
 {
-	struct tpm_buf tbuf;
 	unsigned int body_size;
 	int rc;
 
-	rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_SAVE);
-	if (rc)
-		return rc;
+	struct tpm_buf *tbuf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!tbuf)
+		return -ENOMEM;
 
-	tpm_buf_append_u32(&tbuf, handle);
+	tpm_buf_init(tbuf, TPM_BUFSIZE);
+	tpm_buf_reset(tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_SAVE);
+	tpm_buf_append_u32(tbuf, handle);
 
-	rc = tpm_transmit_cmd(chip, &tbuf, 0, NULL);
+	rc = tpm_transmit_cmd(chip, tbuf, 0, NULL);
 	if (rc < 0) {
 		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
 			 __func__, rc);
-		tpm_buf_destroy(&tbuf);
 		return -EFAULT;
 	} else if (tpm2_rc_value(rc) == TPM2_RC_REFERENCE_H0) {
-		tpm_buf_destroy(&tbuf);
 		return -ENOENT;
 	} else if (rc) {
 		dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
 			 __func__, rc);
-		tpm_buf_destroy(&tbuf);
 		return -EFAULT;
 	}
 
-	body_size = tpm_buf_length(&tbuf) - TPM_HEADER_SIZE;
+	body_size = tpm_buf_length(tbuf) - TPM_HEADER_SIZE;
 	if ((*offset + body_size) > buf_size) {
 		dev_warn(&chip->dev, "%s: out of backing storage\n", __func__);
-		tpm_buf_destroy(&tbuf);
 		return -ENOMEM;
 	}
 
-	memcpy(&buf[*offset], &tbuf.data[TPM_HEADER_SIZE], body_size);
+	memcpy(&buf[*offset], &tbuf->data[TPM_HEADER_SIZE], body_size);
 	*offset += body_size;
-	tpm_buf_destroy(&tbuf);
 	return 0;
 }
 
diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
index 0818bb517805..682dfc93845d 100644
--- a/drivers/char/tpm/tpm_vtpm_proxy.c
+++ b/drivers/char/tpm/tpm_vtpm_proxy.c
@@ -395,40 +395,36 @@ static bool vtpm_proxy_tpm_req_canceled(struct tpm_chip  *chip, u8 status)
 
 static int vtpm_proxy_request_locality(struct tpm_chip *chip, int locality)
 {
-	struct tpm_buf buf;
 	int rc;
 	const struct tpm_header *header;
 	struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
 
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	tpm_buf_init(buf, TPM_BUFSIZE);
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS,
-				  TPM2_CC_SET_LOCALITY);
+		tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_SET_LOCALITY);
 	else
-		rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND,
-				  TPM_ORD_SET_LOCALITY);
-	if (rc)
-		return rc;
-	tpm_buf_append_u8(&buf, locality);
+		tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_SET_LOCALITY);
+
+	tpm_buf_append_u8(buf, locality);
 
 	proxy_dev->state |= STATE_DRIVER_COMMAND;
 
-	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to set locality");
+	rc = tpm_transmit_cmd(chip, buf, 0, "attempting to set locality");
 
 	proxy_dev->state &= ~STATE_DRIVER_COMMAND;
 
-	if (rc < 0) {
-		locality = rc;
-		goto out;
-	}
+	if (rc < 0)
+		return rc;
 
-	header = (const struct tpm_header *)buf.data;
+	header = (const struct tpm_header *)buf->data;
 	rc = be32_to_cpu(header->return_code);
 	if (rc)
 		locality = -1;
 
-out:
-	tpm_buf_destroy(&buf);
-
 	return locality;
 }
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 5a5d8e584e7b..01216156a1ec 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -25,7 +25,8 @@
 #include <crypto/hash_info.h>
 #include <crypto/aes.h>
 
-#define TPM_DIGEST_SIZE 20	/* Max TPM v1.2 PCR size */
+#define TPM_DIGEST_SIZE		20	/* Max TPM v1.2 PCR size */
+#define TPM_BUFSIZE		4096
 
 /*
  * SHA-512 is, as of today, the largest digest in the TCG algorithm repository.
@@ -389,12 +390,14 @@ enum tpm_buf_flags {
 };
 
 /*
- * A string buffer type for constructing TPM commands.
+ * A buffer for constructing and parsing TPM commands, responses and sized
+ * (TPM2B) buffers.
  */
 struct tpm_buf {
-	u32 flags;
-	u32 length;
-	u8 *data;
+	u8 flags;
+	u16 length;
+	u16 capacity;
+	u8 data[];
 };
 
 enum tpm2_object_attributes {
@@ -425,12 +428,11 @@ struct tpm2_hash {
 	unsigned int tpm_id;
 };
 
-int tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal);
+void tpm_buf_init(struct tpm_buf *buf, u16 buf_size);
+void tpm_buf_init_sized(struct tpm_buf *buf, u16 buf_size);
 void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal);
-int tpm_buf_init_sized(struct tpm_buf *buf);
 void tpm_buf_reset_sized(struct tpm_buf *buf);
-void tpm_buf_destroy(struct tpm_buf *buf);
-u32 tpm_buf_length(struct tpm_buf *buf);
+u16 tpm_buf_length(struct tpm_buf *buf);
 void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length);
 void tpm_buf_append_u8(struct tpm_buf *buf, const u8 value);
 void tpm_buf_append_u16(struct tpm_buf *buf, const u16 value);
diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c
index 3d75bb6f9689..368e420c18af 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -320,9 +320,10 @@ static int TSS_checkhmac2(unsigned char *buffer,
  * For key specific tpm requests, we will generate and send our
  * own TPM command packets using the drivers send function.
  */
-static int trusted_tpm_send(unsigned char *cmd, size_t buflen)
+static int trusted_tpm_send(void *cmd, size_t cmd_len)
 {
-	struct tpm_buf buf;
+	u8 buf_data[512];
+	struct tpm_buf *buf = (struct tpm_buf *)buf_data;
 	int rc;
 
 	if (!chip)
@@ -332,11 +333,10 @@ static int trusted_tpm_send(unsigned char *cmd, size_t buflen)
 	if (rc)
 		return rc;
 
-	buf.flags = 0;
-	buf.length = buflen;
-	buf.data = cmd;
+	tpm_buf_init(buf, sizeof(buf_data));
+	tpm_buf_append(buf, cmd, cmd_len);
 	dump_tpm_buf(cmd);
-	rc = tpm_transmit_cmd(chip, &buf, 4, "sending data");
+	rc = tpm_transmit_cmd(chip, buf, 4, "sending data");
 	dump_tpm_buf(cmd);
 
 	if (rc > 0)
@@ -622,23 +622,23 @@ static int tpm_unseal(struct tpm_buf *tb,
 static int key_seal(struct trusted_key_payload *p,
 		    struct trusted_key_options *o)
 {
-	struct tpm_buf tb;
 	int ret;
 
-	ret = tpm_buf_init(&tb, 0, 0);
-	if (ret)
-		return ret;
+	struct tpm_buf *tb __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!tb)
+		return -ENOMEM;
+
+	tpm_buf_init(tb, TPM_BUFSIZE);
 
 	/* include migratable flag at end of sealed key */
 	p->key[p->key_len] = p->migratable;
 
-	ret = tpm_seal(&tb, o->keytype, o->keyhandle, o->keyauth,
+	ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
 		       p->key, p->key_len + 1, p->blob, &p->blob_len,
 		       o->blobauth, o->pcrinfo, o->pcrinfo_len);
 	if (ret < 0)
 		pr_info("srkseal failed (%d)\n", ret);
 
-	tpm_buf_destroy(&tb);
 	return ret;
 }
 
@@ -648,14 +648,15 @@ static int key_seal(struct trusted_key_payload *p,
 static int key_unseal(struct trusted_key_payload *p,
 		      struct trusted_key_options *o)
 {
-	struct tpm_buf tb;
 	int ret;
 
-	ret = tpm_buf_init(&tb, 0, 0);
-	if (ret)
-		return ret;
+	struct tpm_buf *tb __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!tb)
+		return -ENOMEM;
+
+	tpm_buf_init(tb, TPM_BUFSIZE);
 
-	ret = tpm_unseal(&tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
+	ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
 			 o->blobauth, p->key, &p->key_len);
 	if (ret < 0)
 		pr_info("srkunseal failed (%d)\n", ret);
@@ -663,7 +664,6 @@ static int key_unseal(struct trusted_key_payload *p,
 		/* pull migratable flag out of sealed key */
 		p->migratable = p->key[--p->key_len];
 
-	tpm_buf_destroy(&tb);
 	return ret;
 }
 
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 8e694318b200..05c255e67e06 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -205,7 +205,6 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 {
 	u8 parent_name[TPM2_MAX_NAME_SIZE];
 	off_t offset = TPM_HEADER_SIZE;
-	struct tpm_buf buf, sized;
 	u16 parent_name_size;
 	int blob_len = 0;
 	int hash;
@@ -233,98 +232,100 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 	if (rc)
 		goto out_put;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
-	if (rc) {
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf) {
+		rc = -ENOMEM;
 		tpm2_end_auth_session(chip);
 		goto out_put;
 	}
 
-	rc = tpm_buf_init_sized(&sized);
-	if (rc) {
-		tpm_buf_destroy(&buf);
-		tpm2_end_auth_session(chip);
-		goto out_put;
-	}
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
 
-	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, parent_name,
+	rc = tpm_buf_append_name(chip, buf, options->keyhandle, parent_name,
 				 parent_name_size);
 	if (rc)
-		goto out;
+		goto out_put;
 
-	tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT,
+	tpm_buf_append_hmac_session(chip, buf, TPM2_SA_DECRYPT,
 				    options->keyauth, TPM_DIGEST_SIZE);
 
+	struct tpm_buf *sized __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!sized) {
+		rc = -ENOMEM;
+		tpm2_end_auth_session(chip);
+		goto out_put;
+	}
+
 	/* sensitive */
-	tpm_buf_append_u16(&sized, options->blobauth_len);
+	tpm_buf_init_sized(sized, TPM_BUFSIZE);
+	tpm_buf_append_u16(sized, options->blobauth_len);
 
 	if (options->blobauth_len)
-		tpm_buf_append(&sized, options->blobauth, options->blobauth_len);
+		tpm_buf_append(sized, options->blobauth, options->blobauth_len);
 
-	tpm_buf_append_u16(&sized, payload->key_len);
-	tpm_buf_append(&sized, payload->key, payload->key_len);
-	tpm_buf_append(&buf, sized.data, sized.length);
+	tpm_buf_append_u16(sized, payload->key_len);
+	tpm_buf_append(sized, payload->key, payload->key_len);
+	tpm_buf_append(buf, sized->data, sized->length);
 
 	/* public */
-	tpm_buf_reset_sized(&sized);
-	tpm_buf_append_u16(&sized, TPM_ALG_KEYEDHASH);
-	tpm_buf_append_u16(&sized, hash);
+	tpm_buf_init_sized(sized, TPM_BUFSIZE);
+	tpm_buf_append_u16(sized, TPM_ALG_KEYEDHASH);
+	tpm_buf_append_u16(sized, hash);
 
 	/* key properties */
 	flags = 0;
 	flags |= options->policydigest_len ? 0 : TPM2_OA_USER_WITH_AUTH;
 	flags |= payload->migratable ? 0 : (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT);
-	tpm_buf_append_u32(&sized, flags);
+	tpm_buf_append_u32(sized, flags);
 
 	/* policy */
-	tpm_buf_append_u16(&sized, options->policydigest_len);
+	tpm_buf_append_u16(sized, options->policydigest_len);
 	if (options->policydigest_len)
-		tpm_buf_append(&sized, options->policydigest, options->policydigest_len);
+		tpm_buf_append(sized, options->policydigest, options->policydigest_len);
 
 	/* public parameters */
-	tpm_buf_append_u16(&sized, TPM_ALG_NULL);
-	tpm_buf_append_u16(&sized, 0);
+	tpm_buf_append_u16(sized, TPM_ALG_NULL);
+	tpm_buf_append_u16(sized, 0);
 
-	tpm_buf_append(&buf, sized.data, sized.length);
+	tpm_buf_append(buf, sized->data, sized->length);
 
 	/* outside info */
-	tpm_buf_append_u16(&buf, 0);
+	tpm_buf_append_u16(buf, 0);
 
 	/* creation PCR */
-	tpm_buf_append_u32(&buf, 0);
+	tpm_buf_append_u32(buf, 0);
 
-	if (buf.flags & TPM_BUF_INVALID) {
+	if (buf->flags & TPM_BUF_INVALID) {
 		rc = -E2BIG;
 		tpm2_end_auth_session(chip);
 		goto out;
 	}
 
-	rc = tpm_buf_fill_hmac_session(chip, &buf);
+	rc = tpm_buf_fill_hmac_session(chip, buf);
 	if (rc)
 		goto out;
 
-	rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
-	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
+	rc = tpm_transmit_cmd(chip, buf, 4, "sealing data");
+	rc = tpm_buf_check_hmac_response(chip, buf, rc);
 	if (rc)
 		goto out;
 
-	blob_len = tpm_buf_read_u32(&buf, &offset);
-	if (blob_len > MAX_BLOB_SIZE || buf.flags & TPM_BUF_INVALID) {
+	blob_len = tpm_buf_read_u32(buf, &offset);
+	if (blob_len > MAX_BLOB_SIZE || buf->flags & TPM_BUF_INVALID) {
 		rc = -E2BIG;
 		goto out;
 	}
-	if (buf.length - offset < blob_len) {
+	if (buf->length - offset < blob_len) {
 		rc = -EFAULT;
 		goto out;
 	}
 
-	blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);
+	blob_len = tpm2_key_encode(payload, options, &buf->data[offset], blob_len);
 	if (blob_len < 0)
 		rc = blob_len;
 
 out:
-	tpm_buf_destroy(&sized);
-	tpm_buf_destroy(&buf);
-
 	if (!rc)
 		payload->blob_len = blob_len;
 
@@ -356,7 +357,6 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 			 u32 *blob_handle)
 {
 	u8 *blob_ref __free(kfree) = NULL;
-	struct tpm_buf buf;
 	unsigned int private_len;
 	unsigned int public_len;
 	unsigned int blob_len;
@@ -396,40 +396,39 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 	if (rc)
 		return rc;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
-	if (rc) {
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf) {
 		tpm2_end_auth_session(chip);
-		return rc;
+		return -ENOMEM;
 	}
 
-	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, parent_name,
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
+
+	rc = tpm_buf_append_name(chip, buf, options->keyhandle, parent_name,
 				 parent_name_size);
 	if (rc)
-		goto out;
+		return rc;
 
-	tpm_buf_append_hmac_session(chip, &buf, 0, options->keyauth,
+	tpm_buf_append_hmac_session(chip, buf, 0, options->keyauth,
 				    TPM_DIGEST_SIZE);
 
-	tpm_buf_append(&buf, blob, blob_len);
+	tpm_buf_append(buf, blob, blob_len);
 
-	if (buf.flags & TPM_BUF_INVALID) {
-		rc = -E2BIG;
+	if (buf->flags & TPM_BUF_INVALID) {
 		tpm2_end_auth_session(chip);
-		goto out;
+		return -E2BIG;
 	}
 
-	rc = tpm_buf_fill_hmac_session(chip, &buf);
+	rc = tpm_buf_fill_hmac_session(chip, buf);
 	if (rc)
-		goto out;
+		return rc;
 
-	rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
-	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
+	rc = tpm_transmit_cmd(chip, buf, 4, "loading blob");
+	rc = tpm_buf_check_hmac_response(chip, buf, rc);
 	if (!rc)
 		*blob_handle = be32_to_cpup(
-			(__be32 *) &buf.data[TPM_HEADER_SIZE]);
-
-out:
-	tpm_buf_destroy(&buf);
+			(__be32 *)&buf->data[TPM_HEADER_SIZE]);
 
 	return tpm_ret_to_err(rc);
 }
@@ -454,28 +453,28 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 			   u16 parent_name_size,
 			   u32 blob_handle)
 {
-	struct tpm_buf buf;
 	u16 data_len;
 	u8 *data;
 	int rc;
 
+	struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
 	rc = tpm2_start_auth_session(chip);
 	if (rc)
 		return rc;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
-	if (rc) {
-		tpm2_end_auth_session(chip);
-		return rc;
-	}
+	tpm_buf_init(buf, TPM_BUFSIZE);
+	tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
 
-	rc = tpm_buf_append_name(chip, &buf, blob_handle, parent_name,
+	rc = tpm_buf_append_name(chip, buf, blob_handle, parent_name,
 				 parent_name_size);
 	if (rc)
-		goto out;
+		return rc;
 
 	if (!options->policyhandle) {
-		tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT,
+		tpm_buf_append_hmac_session(chip, buf, TPM2_SA_ENCRYPT,
 					    options->blobauth,
 					    options->blobauth_len);
 	} else {
@@ -490,37 +489,33 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 		 * could repeat our actions with the exfiltrated
 		 * password.
 		 */
-		tpm_buf_append_u32(&buf, 9 + options->blobauth_len);
-		tpm_buf_append_u32(&buf, options->policyhandle);
-		tpm_buf_append_u16(&buf, 0);
-		tpm_buf_append_u8(&buf, 0);
-		tpm_buf_append_u16(&buf, options->blobauth_len);
-		tpm_buf_append(&buf, options->blobauth, options->blobauth_len);
+		tpm_buf_append_u32(buf, 9 + options->blobauth_len);
+		tpm_buf_append_u32(buf, options->policyhandle);
+		tpm_buf_append_u16(buf, 0);
+		tpm_buf_append_u8(buf, 0);
+		tpm_buf_append_u16(buf, options->blobauth_len);
+		tpm_buf_append(buf, options->blobauth, options->blobauth_len);
 
 		if (tpm2_chip_auth(chip))
-			tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT, NULL, 0);
+			tpm_buf_append_hmac_session(chip, buf, TPM2_SA_ENCRYPT, NULL, 0);
 	}
 
-	rc = tpm_buf_fill_hmac_session(chip, &buf);
+	rc = tpm_buf_fill_hmac_session(chip, buf);
 	if (rc)
-		goto out;
+		return rc;
 
-	rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
-	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
+	rc = tpm_transmit_cmd(chip, buf, 6, "unsealing");
+	rc = tpm_buf_check_hmac_response(chip, buf, rc);
 
 	if (!rc) {
 		data_len = be16_to_cpup(
-			(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
-		if (data_len < MIN_KEY_SIZE ||  data_len > MAX_KEY_SIZE) {
-			rc = -EFAULT;
-			goto out;
-		}
+			(__be16 *)&buf->data[TPM_HEADER_SIZE + 4]);
+		if (data_len < MIN_KEY_SIZE ||  data_len > MAX_KEY_SIZE)
+			return -EFAULT;
 
-		if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
-			rc = -EFAULT;
-			goto out;
-		}
-		data = &buf.data[TPM_HEADER_SIZE + 6];
+		if (tpm_buf_length(buf) < TPM_HEADER_SIZE + 6 + data_len)
+			return -EFAULT;
+		data = &buf->data[TPM_HEADER_SIZE + 6];
 
 		if (payload->old_format) {
 			/* migratable flag is at the end of the key */
@@ -537,8 +532,6 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 		}
 	}
 
-out:
-	tpm_buf_destroy(&buf);
 	return tpm_ret_to_err(rc);
 }
 
-- 
2.52.0


^ permalink raw reply related

* [PATCH v9 10/11] tpm-buf: Merge TPM_BUF_BOUNDARY_ERROR and TPM_BUF_OVERFLOW
From: Jarkko Sakkinen @ 2026-01-25 19:25 UTC (permalink / raw)
  To: linux-integrity
  Cc: Jarkko Sakkinen, Jonathan McDowell, James Bottomley,
	Jarkko Sakkinen, Mimi Zohar, David Howells, Paul Moore,
	James Morris, Serge E. Hallyn, open list:KEYS-TRUSTED,
	open list:SECURITY SUBSYSTEM, open list
In-Reply-To: <20260125192526.782202-1-jarkko@kernel.org>

From: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>

Merge TPM_BUF_BOUNDARY_ERROR and TPM_BUF_OVERFLOW into TPM_BUF_INVALID,
given that they are identical. The only difference are the log messages.

In addition, add a missing TPM_BUF_INVALID check to tpm_buf_append_handle()
following the pattern from other functions in tpm-buf.c.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>
Reviewed-by: Jonathan McDowell <noodles@meta.com>
---
 drivers/char/tpm/tpm-buf.c                | 10 ++++------
 include/linux/tpm.h                       |  8 +++-----
 security/keys/trusted-keys/trusted_tpm2.c |  6 +++---
 3 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index 1d2b87455d3a..11b6bcf2f43d 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -103,13 +103,12 @@ EXPORT_SYMBOL_GPL(tpm_buf_length);
  */
 void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length)
 {
-	/* Return silently if overflow has already happened. */
-	if (buf->flags & TPM_BUF_OVERFLOW)
+	if (buf->flags & TPM_BUF_INVALID)
 		return;
 
 	if ((buf->length + new_length) > PAGE_SIZE) {
 		WARN(1, "tpm_buf: write overflow\n");
-		buf->flags |= TPM_BUF_OVERFLOW;
+		buf->flags |= TPM_BUF_INVALID;
 		return;
 	}
 
@@ -156,14 +155,13 @@ static void tpm_buf_read(struct tpm_buf *buf, off_t *offset, size_t count, void
 {
 	off_t next_offset;
 
-	/* Return silently if overflow has already happened. */
-	if (buf->flags & TPM_BUF_BOUNDARY_ERROR)
+	if (buf->flags & TPM_BUF_INVALID)
 		return;
 
 	next_offset = *offset + count;
 	if (next_offset > buf->length) {
 		WARN(1, "tpm_buf: read out of boundary\n");
-		buf->flags |= TPM_BUF_BOUNDARY_ERROR;
+		buf->flags |= TPM_BUF_INVALID;
 		return;
 	}
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index e8339f0c9a2e..5a5d8e584e7b 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -382,12 +382,10 @@ struct tpm_header {
 } __packed;
 
 enum tpm_buf_flags {
-	/* the capacity exceeded: */
-	TPM_BUF_OVERFLOW	= BIT(0),
 	/* TPM2B format: */
-	TPM_BUF_TPM2B		= BIT(1),
-	/* read out of boundary: */
-	TPM_BUF_BOUNDARY_ERROR	= BIT(2),
+	TPM_BUF_TPM2B		= BIT(0),
+	/* The buffer is in invalid and unusable state: */
+	TPM_BUF_INVALID		= BIT(1),
 };
 
 /*
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index dbacebe7af56..8e694318b200 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -292,7 +292,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 	/* creation PCR */
 	tpm_buf_append_u32(&buf, 0);
 
-	if (buf.flags & TPM_BUF_OVERFLOW) {
+	if (buf.flags & TPM_BUF_INVALID) {
 		rc = -E2BIG;
 		tpm2_end_auth_session(chip);
 		goto out;
@@ -308,7 +308,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		goto out;
 
 	blob_len = tpm_buf_read_u32(&buf, &offset);
-	if (blob_len > MAX_BLOB_SIZE || buf.flags & TPM_BUF_BOUNDARY_ERROR) {
+	if (blob_len > MAX_BLOB_SIZE || buf.flags & TPM_BUF_INVALID) {
 		rc = -E2BIG;
 		goto out;
 	}
@@ -412,7 +412,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 
 	tpm_buf_append(&buf, blob, blob_len);
 
-	if (buf.flags & TPM_BUF_OVERFLOW) {
+	if (buf.flags & TPM_BUF_INVALID) {
 		rc = -E2BIG;
 		tpm2_end_auth_session(chip);
 		goto out;
-- 
2.52.0


^ permalink raw reply related

* [PATCH v9 09/11] tpm-buf: Remove tpm_buf_append_handle
From: Jarkko Sakkinen @ 2026-01-25 19:25 UTC (permalink / raw)
  To: linux-integrity
  Cc: Jarkko Sakkinen, James Bottomley, Mimi Zohar, David Howells,
	Paul Moore, James Morris, Serge E. Hallyn, open list:KEYS-TRUSTED,
	open list:SECURITY SUBSYSTEM, open list
In-Reply-To: <20260125192526.782202-1-jarkko@kernel.org>

Since the number of handles is fixed to a single handle, eliminate all uses
of buf->handles and deduce values during compile-time.

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v2:
- Streamline the code change and remove dead code.
---
 drivers/char/tpm/tpm-buf.c       | 23 -----------------------
 drivers/char/tpm/tpm2-cmd.c      |  2 +-
 drivers/char/tpm/tpm2-sessions.c | 14 ++------------
 include/linux/tpm.h              |  2 --
 4 files changed, 3 insertions(+), 38 deletions(-)

diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index dc882fc9fa9e..1d2b87455d3a 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -44,7 +44,6 @@ void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal)
 	head->tag = cpu_to_be16(tag);
 	head->length = cpu_to_be32(sizeof(*head));
 	head->ordinal = cpu_to_be32(ordinal);
-	buf->handles = 0;
 }
 EXPORT_SYMBOL_GPL(tpm_buf_reset);
 
@@ -146,26 +145,6 @@ void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value)
 }
 EXPORT_SYMBOL_GPL(tpm_buf_append_u32);
 
-/**
- * tpm_buf_append_handle() - Add a handle
- * @chip:	&tpm_chip instance
- * @buf:	&tpm_buf instance
- * @handle:	a TPM object handle
- *
- * Add a handle to the buffer, and increase the count tracking the number of
- * handles in the command buffer. Works only for command buffers.
- */
-void tpm_buf_append_handle(struct tpm_chip *chip, struct tpm_buf *buf, u32 handle)
-{
-	if (buf->flags & TPM_BUF_TPM2B) {
-		dev_err(&chip->dev, "Invalid buffer type (TPM2B)\n");
-		return;
-	}
-
-	tpm_buf_append_u32(buf, handle);
-	buf->handles++;
-}
-
 /**
  * tpm_buf_read() - Read from a TPM buffer
  * @buf:	&tpm_buf instance
@@ -242,5 +221,3 @@ u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset)
 	return be32_to_cpu(value);
 }
 EXPORT_SYMBOL_GPL(tpm_buf_read_u32);
-
-
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 96a45391036c..39ef6b7a0fbc 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -210,7 +210,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 		}
 		tpm_buf_append_hmac_session(chip, &buf, 0, NULL, 0);
 	} else {
-		tpm_buf_append_handle(chip, &buf, pcr_idx);
+		tpm_buf_append_u32(&buf, pcr_idx);
 		tpm_buf_append_auth(chip, &buf, NULL, 0);
 	}
 
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 98cea20040cf..016bed63a755 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -268,7 +268,7 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
 	}
 
 	if (!tpm2_chip_auth(chip)) {
-		tpm_buf_append_handle(chip, buf, handle);
+		tpm_buf_append_u32(buf, handle);
 		return 0;
 	}
 
@@ -295,17 +295,7 @@ EXPORT_SYMBOL_GPL(tpm_buf_append_name);
 void tpm_buf_append_auth(struct tpm_chip *chip, struct tpm_buf *buf,
 			 u8 *passphrase, int passphrase_len)
 {
-	/* offset tells us where the sessions area begins */
-	int offset = buf->handles * 4 + TPM_HEADER_SIZE;
-	u32 len = 9 + passphrase_len;
-
-	if (tpm_buf_length(buf) != offset) {
-		/* not the first session so update the existing length */
-		len += get_unaligned_be32(&buf->data[offset]);
-		put_unaligned_be32(len, &buf->data[offset]);
-	} else {
-		tpm_buf_append_u32(buf, len);
-	}
+	tpm_buf_append_u32(buf, 9 + passphrase_len);
 	/* auth handle */
 	tpm_buf_append_u32(buf, TPM2_RS_PW);
 	/* nonce */
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 7468709ad245..e8339f0c9a2e 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -397,7 +397,6 @@ struct tpm_buf {
 	u32 flags;
 	u32 length;
 	u8 *data;
-	u8 handles;
 };
 
 enum tpm2_object_attributes {
@@ -441,7 +440,6 @@ void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value);
 u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset);
 u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset);
 u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset);
-void tpm_buf_append_handle(struct tpm_chip *chip, struct tpm_buf *buf, u32 handle);
 
 /*
  * Check if TPM device is in the firmware upgrade mode.
-- 
2.52.0


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