* [PATCH v3 1/7] KEYS: trusted: Remove dead branch from tpm2_unseal_cmd
From: Jarkko Sakkinen @ 2025-12-10 14:39 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, David Howells, Paul Moore, James Morris,
Serge E. Hallyn, James Bottomley, Mimi Zohar,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM, open list
In-Reply-To: <20251210143940.264191-1-jarkko@kernel.org>
TPM2_Unseal requires TPM2_ST_SESSIONS, and tpm2_unseal_cmd() always does
set up either password or HMAC session.
Remove the branch in tpm2_unseal_cmd() conditionally setting
TPM2_ST_NO_SESSIONS. It is faulty but luckily it is never exercised at
run-time, and thus does not cause regressions.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
security/keys/trusted-keys/trusted_tpm2.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 9074ae1a5896..27424e1a4a63 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -450,9 +450,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
struct trusted_key_options *options,
u32 blob_handle)
{
- struct tpm_header *head;
u16 data_len;
- int offset;
u8 *data;
int rc;
@@ -488,14 +486,8 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
tpm_buf_append_u16(buf, options->blobauth_len);
tpm_buf_append(buf, options->blobauth, options->blobauth_len);
- if (tpm2_chip_auth(chip)) {
+ if (tpm2_chip_auth(chip))
tpm_buf_append_hmac_session(chip, buf, TPM2_SA_ENCRYPT, NULL, 0);
- } else {
- offset = buf->handles * 4 + TPM_HEADER_SIZE;
- head = (struct tpm_header *)buf->data;
- if (tpm_buf_length(buf) == offset)
- head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
- }
}
rc = tpm_buf_fill_hmac_session(chip, buf);
--
2.52.0
^ permalink raw reply related
* [PATCH v3 2/7] tpm2-sessions: Define TPM2_NAME_MAX_SIZE
From: Jarkko Sakkinen @ 2025-12-10 14:39 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210143940.264191-1-jarkko@kernel.org>
This is somewhat cosmetic change but it does serve a purpose on tracking
the value set for the maximum length of TPM names, and to clearly states
what components it is composed of. It also anchors the value so that when
buffers are declared for this particular purpose, the same value is used
for the capacity.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v2:
- Rename TPM2_NAME_SIZE as TPM2_NULL_NAME_SIZE.
---
drivers/char/tpm/tpm-sysfs.c | 2 +-
drivers/char/tpm/tpm2-sessions.c | 2 +-
include/linux/tpm.h | 37 +++++++++++++++++++++-----------
3 files changed, 27 insertions(+), 14 deletions(-)
diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index f5dcadb1ab3c..0f321c307bc6 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -313,7 +313,7 @@ static ssize_t null_name_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct tpm_chip *chip = to_tpm_chip(dev);
- int size = TPM2_NAME_SIZE;
+ int size = TPM2_NULL_NAME_SIZE;
bin2hex(buf, chip->null_key_name, size);
size *= 2;
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 79f27a46bd7f..a0c88fb1804c 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -137,7 +137,7 @@ struct tpm2_auth {
* we must compute and remember
*/
u32 name_h[AUTH_MAX_NAMES];
- u8 name[AUTH_MAX_NAMES][2 + SHA512_DIGEST_SIZE];
+ u8 name[AUTH_MAX_NAMES][TPM2_MAX_NAME_SIZE];
};
#ifdef CONFIG_TCG_TPM2_HMAC
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 42e2a091f43d..922a43ef23b5 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -28,9 +28,33 @@
#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.
+ */
#define TPM2_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE
+
+/*
+ * A TPM name digest i.e., TPMT_HA, is a concatenation of TPM_ALG_ID of the
+ * name algorithm and hash of TPMT_PUBLIC.
+ */
+#define TPM2_MAX_NAME_SIZE (TPM2_MAX_DIGEST_SIZE + 2)
+
+/*
+ * The maximum number of PCR banks.
+ */
#define TPM2_MAX_PCR_BANKS 8
+/*
+ * fixed define for the size of a name. This is actually HASHALG size
+ * plus 2, so 32 for SHA256
+ */
+#define TPM2_NULL_NAME_SIZE 34
+
+/*
+ * The maximum size for an object context
+ */
+#define TPM2_MAX_CONTEXT_SIZE 4096
+
struct tpm_chip;
struct trusted_key_payload;
struct trusted_key_options;
@@ -140,17 +164,6 @@ struct tpm_chip_seqops {
/* fixed define for the curve we use which is NIST_P256 */
#define EC_PT_SZ 32
-/*
- * fixed define for the size of a name. This is actually HASHALG size
- * plus 2, so 32 for SHA256
- */
-#define TPM2_NAME_SIZE 34
-
-/*
- * The maximum size for an object context
- */
-#define TPM2_MAX_CONTEXT_SIZE 4096
-
struct tpm_chip {
struct device dev;
struct device devs;
@@ -212,7 +225,7 @@ struct tpm_chip {
/* saved context for NULL seed */
u8 null_key_context[TPM2_MAX_CONTEXT_SIZE];
/* name of NULL seed */
- u8 null_key_name[TPM2_NAME_SIZE];
+ u8 null_key_name[TPM2_NULL_NAME_SIZE];
u8 null_ec_key_x[EC_PT_SZ];
u8 null_ec_key_y[EC_PT_SZ];
struct tpm2_auth *auth;
--
2.52.0
^ permalink raw reply related
* [PATCH v3 3/7] KEYS: trusted: Re-orchestrate tpm2_read_public() calls
From: Jarkko Sakkinen @ 2025-12-10 14:39 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, James Bottomley,
Mimi Zohar, open list, open list:KEYS/KEYRINGS,
open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210143940.264191-1-jarkko@kernel.org>
tpm2_load_cmd() and tpm2_unseal_cmd() use the same parent, and calls to
tpm_buf_append_name() cause the exact same TPM2_ReadPublic command to be
sent to the chip, causing unnecessary traffic.
1. Export tpm2_read_public in order to make it callable from
'trusted_tpm2'.
2. Re-orchestrate tpm2_seal_trusted() and tpm2_unseal_trusted() in order to
halve the name resolutions required:
2a. Move tpm2_read_public() calls into trusted_tpm2.
2b. Pass TPM name to tpm_buf_append_name().
2c. Rework tpm_buf_append_name() to use the pre-resolved name.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
drivers/char/tpm/tpm2-cmd.c | 3 +-
drivers/char/tpm/tpm2-sessions.c | 95 +++++------------
include/linux/tpm.h | 10 +-
security/keys/trusted-keys/trusted_tpm2.c | 124 ++++++++++++++--------
4 files changed, 118 insertions(+), 114 deletions(-)
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 543c1c62c938..436ee82620e4 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -199,7 +199,8 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
if (!disable_pcr_integrity) {
- rc = tpm_buf_append_name(chip, buf, pcr_idx, NULL);
+ rc = tpm_buf_append_name(chip, buf, pcr_idx, (u8 *)&pcr_idx,
+ sizeof(u32));
if (rc)
return rc;
tpm_buf_append_hmac_session(chip, buf, 0, NULL, 0);
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index a0c88fb1804c..0816a91134fc 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -136,8 +136,8 @@ struct tpm2_auth {
* handle, but they are part of the session by name, which
* we must compute and remember
*/
- u32 name_h[AUTH_MAX_NAMES];
u8 name[AUTH_MAX_NAMES][TPM2_MAX_NAME_SIZE];
+ u16 name_size_tbl[AUTH_MAX_NAMES];
};
#ifdef CONFIG_TCG_TPM2_HMAC
@@ -163,7 +163,17 @@ static int name_size(const u8 *name)
}
}
-static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
+/**
+ * tpm2_read_public: Resolve TPM name for a handle
+ * @chip: TPM chip to use.
+ * @handle: TPM handle.
+ * @name: A buffer for returning the name blob. Must have a
+ * capacity of 'SHA512_DIGET_SIZE + 2' bytes at minimum
+ *
+ * Returns size of TPM handle name of success.
+ * Returns tpm_transmit_cmd error codes when TPM2_ReadPublic fails.
+ */
+int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
{
u32 mso = tpm2_handle_mso(handle);
off_t offset = TPM_HEADER_SIZE;
@@ -212,14 +222,16 @@ static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
memcpy(name, &buf->data[offset], rc);
return name_size_alg;
}
+EXPORT_SYMBOL_GPL(tpm2_read_public);
#endif /* CONFIG_TCG_TPM2_HMAC */
/**
- * tpm_buf_append_name() - add a handle area to the buffer
- * @chip: the TPM chip structure
- * @buf: The buffer to be appended
- * @handle: The handle to be appended
- * @name: The name of the handle (may be NULL)
+ * tpm_buf_append_name() - Append a handle and store TPM name
+ * @chip: TPM chip to use.
+ * @buf: TPM buffer containing the TPM command in-transit.
+ * @handle: TPM handle to be appended.
+ * @name: TPM name of the handle
+ * @name_size: Size of the TPM name.
*
* In order to compute session HMACs, we need to know the names of the
* objects pointed to by the handles. For most objects, this is simply
@@ -236,15 +248,14 @@ static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
* will be caused by an incorrect programming model and indicated by a
* kernel message.
*
- * Ends the authorization session on failure.
+ * Returns zero on success.
+ * Returns -EIO when the authorization area state is malformed.
*/
int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
- u32 handle, u8 *name)
+ u32 handle, u8 *name, u16 name_size)
{
#ifdef CONFIG_TCG_TPM2_HMAC
- enum tpm2_mso_type mso = tpm2_handle_mso(handle);
struct tpm2_auth *auth;
- u16 name_size_alg;
int slot;
int ret;
#endif
@@ -269,36 +280,15 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}
tpm_buf_append_u32(buf, handle);
auth->session += 4;
-
- if (mso == TPM2_MSO_PERSISTENT ||
- mso == TPM2_MSO_VOLATILE ||
- mso == TPM2_MSO_NVRAM) {
- if (!name) {
- ret = tpm2_read_public(chip, handle, auth->name[slot]);
- if (ret < 0)
- goto err;
-
- name_size_alg = ret;
- }
- } else {
- if (name) {
- dev_err(&chip->dev, "handle 0x%08x does not use a name\n",
- handle);
- ret = -EIO;
- goto err;
- }
- }
-
- auth->name_h[slot] = handle;
- if (name)
- memcpy(auth->name[slot], name, name_size_alg);
+ memcpy(auth->name[slot], name, name_size);
+ auth->name_size_tbl[slot] = name_size;
#endif
return 0;
#ifdef CONFIG_TCG_TPM2_HMAC
err:
tpm2_end_auth_session(chip);
- return tpm_ret_to_err(ret);
+ return ret;
#endif
}
EXPORT_SYMBOL_GPL(tpm_buf_append_name);
@@ -606,22 +596,8 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
attrs = chip->cc_attrs_tbl[i];
handles = (attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0);
+ offset_s += handles * sizeof(u32);
- /*
- * just check the names, it's easy to make mistakes. This
- * would happen if someone added a handle via
- * tpm_buf_append_u32() instead of tpm_buf_append_name()
- */
- for (i = 0; i < handles; i++) {
- u32 handle = tpm_buf_read_u32(buf, &offset_s);
-
- if (auth->name_h[i] != handle) {
- dev_err(&chip->dev, "invalid handle 0x%08x\n", handle);
- ret = -EIO;
- goto err;
- }
- }
- /* point offset_s to the start of the sessions */
val = tpm_buf_read_u32(buf, &offset_s);
/* point offset_p to the start of the parameters */
offset_p = offset_s + val;
@@ -682,23 +658,8 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
/* ordinal is already BE */
sha256_update(&sctx, (u8 *)&head->ordinal, sizeof(head->ordinal));
/* add the handle names */
- for (i = 0; i < handles; i++) {
- enum tpm2_mso_type mso = tpm2_handle_mso(auth->name_h[i]);
-
- if (mso == TPM2_MSO_PERSISTENT ||
- mso == TPM2_MSO_VOLATILE ||
- mso == TPM2_MSO_NVRAM) {
- ret = name_size(auth->name[i]);
- if (ret < 0)
- goto err;
-
- sha256_update(&sctx, auth->name[i], ret);
- } else {
- __be32 h = cpu_to_be32(auth->name_h[i]);
-
- sha256_update(&sctx, (u8 *)&h, 4);
- }
- }
+ for (i = 0; i < handles; i++)
+ sha256_update(&sctx, auth->name[i], auth->name_size_tbl[i]);
if (offset_s != tpm_buf_length(buf))
sha256_update(&sctx, &buf->data[offset_s],
tpm_buf_length(buf) - offset_s);
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 922a43ef23b5..9f684fc7ae04 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -543,7 +543,7 @@ static inline struct tpm2_auth *tpm2_chip_auth(struct tpm_chip *chip)
}
int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
- u32 handle, u8 *name);
+ u32 handle, u8 *name, u16 name_size);
void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf,
u8 attributes, u8 *passphrase,
int passphraselen);
@@ -557,6 +557,7 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf);
int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf,
int rc);
void tpm2_end_auth_session(struct tpm_chip *chip);
+int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name);
#else
#include <linux/unaligned.h>
@@ -580,6 +581,13 @@ static inline int tpm_buf_check_hmac_response(struct tpm_chip *chip,
{
return rc;
}
+
+static inline int tpm2_read_public(struct tpm_chip *chip, u32 handle,
+ void *name)
+{
+ memcpy(name, &handle, sizeof(u32));
+ return sizeof(u32);
+}
#endif /* CONFIG_TCG_TPM2_HMAC */
#endif
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 27424e1a4a63..63539b344ffb 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -203,7 +203,9 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options)
{
+ u8 parent_name[TPM2_MAX_NAME_SIZE];
off_t offset = TPM_HEADER_SIZE;
+ u16 parent_name_size;
int blob_len = 0;
int hash;
u32 flags;
@@ -220,6 +222,12 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
if (rc)
return rc;
+ rc = tpm2_read_public(chip, options->keyhandle, parent_name);
+ if (rc < 0)
+ goto out_put;
+
+ parent_name_size = rc;
+
rc = tpm2_start_auth_session(chip);
if (rc)
goto out_put;
@@ -234,7 +242,8 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
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, NULL);
+ rc = tpm_buf_append_name(chip, buf, options->keyhandle, parent_name,
+ parent_name_size);
if (rc)
goto out_put;
@@ -326,48 +335,38 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
}
/**
- * tpm2_load_cmd() - execute a TPM2_Load command
- *
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- * @blob_handle: returned blob handle
+ * tpm2_load_cmd() - Execute TPM2_Load
+ * @chip: TPM chip to use.
+ * @payload: Key data in clear text.
+ * @options: Trusted key options.
+ * @parent_name: A cryptographic name, i.e. a TPMT_HA blob, of the
+ * parent key.
+ * @blob: The decoded payload for the key.
+ * @blob_handle: On success, will contain handle to the loaded keyedhash
+ * blob.
*
- * Return: 0 on success.
- * -E2BIG on wrong payload size.
- * -EPERM on tpm error status.
- * < 0 error from tpm_send.
+ * Return -E2BIG when the blob size is too small for all the data.
+ * Returns tpm_transmit_cmd() error codes when either TPM2_Load fails.
*/
static int tpm2_load_cmd(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options,
+ u8 *parent_name,
+ u16 parent_name_size,
+ const u8 *blob,
u32 *blob_handle)
{
u8 *blob_ref __free(kfree) = NULL;
unsigned int private_len;
unsigned int public_len;
unsigned int blob_len;
- u8 *blob, *pub;
+ const u8 *pub;
int rc;
u32 attrs;
- rc = tpm2_key_decode(payload, options, &blob);
- if (rc) {
- /* old form */
- blob = payload->blob;
- payload->old_format = 1;
- } else {
- /* Bind for cleanup: */
- blob_ref = blob;
- }
-
- /* new format carries keyhandle but old format doesn't */
- if (!options->keyhandle)
- return -EINVAL;
-
/* must be big enough for at least the two be16 size counts */
if (payload->blob_len < 4)
- return -EINVAL;
+ return -E2BIG;
private_len = get_unaligned_be16(blob);
@@ -406,7 +405,8 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
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, NULL);
+ rc = tpm_buf_append_name(chip, buf, options->keyhandle, parent_name,
+ parent_name_size);
if (rc)
return rc;
@@ -434,20 +434,23 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
}
/**
- * tpm2_unseal_cmd() - execute a TPM2_Unload command
+ * tpm2_unseal_cmd() - Execute TPM2_Unload
*
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- * @blob_handle: blob handle
+ * @chip: TPM chip to use
+ * @payload: Key data in clear text.
+ * @options: Trusted key options.
+ * @parent_name: A cryptographic name, i.e. a TPMT_HA blob, of the
+ * parent key.
+ * @blob_handle: Handle to the loaded keyedhash blob.
*
- * Return: 0 on success
- * -EPERM on tpm error status
- * < 0 error from tpm_send
+ * Return -E2BIG when the blob size is too small for all the data.
+ * Returns tpm_transmit_cmd() error codes when either TPM2_Load fails.
*/
static int tpm2_unseal_cmd(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options,
+ u8 *parent_name,
+ u16 parent_name_size,
u32 blob_handle)
{
u16 data_len;
@@ -465,7 +468,8 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
tpm_buf_init(buf, TPM_BUFSIZE);
tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
- rc = tpm_buf_append_name(chip, buf, options->keyhandle, NULL);
+ rc = tpm_buf_append_name(chip, buf, options->keyhandle, parent_name,
+ parent_name_size);
if (rc)
return rc;
@@ -526,30 +530,60 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
}
/**
- * tpm2_unseal_trusted() - unseal the payload of a trusted key
+ * tpm2_unseal_trusted() - Unseal a trusted key
+ * @chip: TPM chip to use.
+ * @payload: Key data in clear text.
+ * @options: Trusted key options.
*
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- *
- * Return: Same as with tpm_send.
+ * Return -E2BIG when the blob size is too small for all the data.
+ * Return -EINVAL when parent's key handle has not been set.
+ * Returns tpm_transmit_cmd() error codes when either TPM2_Load or TPM2_Unseal
+ * fails.
*/
int tpm2_unseal_trusted(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options)
{
+ u8 *blob_ref __free(kfree) = NULL;
+ u8 parent_name[TPM2_MAX_NAME_SIZE];
+ u16 parent_name_size;
u32 blob_handle;
+ u8 *blob;
int rc;
+ /*
+ * Try to decode the provided blob as an ASN.1 blob. Assume that the
+ * blob is in the legacy format if decoding does not end successfully.
+ */
+ rc = tpm2_key_decode(payload, options, &blob);
+ if (rc) {
+ blob = payload->blob;
+ payload->old_format = 1;
+ } else {
+ blob_ref = blob;
+ }
+
+ if (!options->keyhandle)
+ return -EINVAL;
+
rc = tpm_try_get_ops(chip);
if (rc)
return rc;
- rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
+ rc = tpm2_read_public(chip, options->keyhandle, parent_name);
+ if (rc < 0)
+ goto out;
+
+ parent_name_size = rc;
+
+ rc = tpm2_load_cmd(chip, payload, options, parent_name,
+ parent_name_size, blob, &blob_handle);
if (rc)
goto out;
- rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
+ rc = tpm2_unseal_cmd(chip, payload, options, parent_name,
+ parent_name_size, blob_handle);
+
tpm2_flush_context(chip, blob_handle);
out:
--
2.52.0
^ permalink raw reply related
* [PATCH v3 4/7] tpm2-sessions: Remove AUTH_MAX_NAMES
From: Jarkko Sakkinen @ 2025-12-10 14:39 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210143940.264191-1-jarkko@kernel.org>
In all of the call sites only one session is ever append. Thus, reduce
AUTH_MAX_NAMES, which leads into removing constant completely.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
drivers/char/tpm/tpm2-sessions.c | 31 +++++++++++--------------------
1 file changed, 11 insertions(+), 20 deletions(-)
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 0816a91134fc..62a200ae72d7 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -72,9 +72,6 @@
#include <crypto/sha2.h>
#include <crypto/utils.h>
-/* maximum number of names the TPM must remember for authorization */
-#define AUTH_MAX_NAMES 3
-
#define AES_KEY_BYTES AES_KEYSIZE_128
#define AES_KEY_BITS (AES_KEY_BYTES*8)
@@ -136,8 +133,8 @@ struct tpm2_auth {
* handle, but they are part of the session by name, which
* we must compute and remember
*/
- u8 name[AUTH_MAX_NAMES][TPM2_MAX_NAME_SIZE];
- u16 name_size_tbl[AUTH_MAX_NAMES];
+ u8 name[TPM2_MAX_NAME_SIZE];
+ u16 name_size;
};
#ifdef CONFIG_TCG_TPM2_HMAC
@@ -254,11 +251,14 @@ EXPORT_SYMBOL_GPL(tpm2_read_public);
int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
u32 handle, u8 *name, u16 name_size)
{
-#ifdef CONFIG_TCG_TPM2_HMAC
struct tpm2_auth *auth;
- int slot;
int ret;
-#endif
+
+ if (tpm_buf_length(buf) != TPM_HEADER_SIZE) {
+ dev_err(&chip->dev, "too many handles\n");
+ ret = -EIO;
+ goto err;
+ }
if (!tpm2_chip_auth(chip)) {
tpm_buf_append_handle(buf, handle);
@@ -266,12 +266,6 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}
#ifdef CONFIG_TCG_TPM2_HMAC
- slot = (tpm_buf_length(buf) - TPM_HEADER_SIZE) / 4;
- if (slot >= AUTH_MAX_NAMES) {
- dev_err(&chip->dev, "too many handles\n");
- ret = -EIO;
- goto err;
- }
auth = chip->auth;
if (auth->session != tpm_buf_length(buf)) {
dev_err(&chip->dev, "session state malformed");
@@ -280,16 +274,14 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}
tpm_buf_append_u32(buf, handle);
auth->session += 4;
- memcpy(auth->name[slot], name, name_size);
- auth->name_size_tbl[slot] = name_size;
+ memcpy(auth->name, name, name_size);
+ auth->name_size = name_size;
#endif
return 0;
-#ifdef CONFIG_TCG_TPM2_HMAC
err:
tpm2_end_auth_session(chip);
return ret;
-#endif
}
EXPORT_SYMBOL_GPL(tpm_buf_append_name);
@@ -658,8 +650,7 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
/* ordinal is already BE */
sha256_update(&sctx, (u8 *)&head->ordinal, sizeof(head->ordinal));
/* add the handle names */
- for (i = 0; i < handles; i++)
- sha256_update(&sctx, auth->name[i], auth->name_size_tbl[i]);
+ sha256_update(&sctx, auth->name, auth->name_size);
if (offset_s != tpm_buf_length(buf))
sha256_update(&sctx, &buf->data[offset_s],
tpm_buf_length(buf) - offset_s);
--
2.52.0
^ permalink raw reply related
* [PATCH v3 5/7] tpm-buf: Remove tpm_buf_append_handle
From: Jarkko Sakkinen @ 2025-12-10 14:39 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210143940.264191-1-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 | 25 -------------------------
drivers/char/tpm/tpm2-cmd.c | 6 ++----
drivers/char/tpm/tpm2-sessions.c | 14 ++------------
include/linux/tpm.h | 2 --
4 files changed, 4 insertions(+), 43 deletions(-)
diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index 73be8a87b472..752c69b8a4f5 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -40,7 +40,6 @@ static void __tpm_buf_reset(struct tpm_buf *buf, u16 buf_size, u16 tag, u32 ordi
buf->flags = 0;
buf->length = sizeof(*head);
buf->capacity = buf_size - sizeof(*buf);
- buf->handles = 0;
head->tag = cpu_to_be16(tag);
head->length = cpu_to_be32(sizeof(*head));
head->ordinal = cpu_to_be32(ordinal);
@@ -56,7 +55,6 @@ static void __tpm_buf_reset_sized(struct tpm_buf *buf, u16 buf_size)
buf->flags = TPM_BUF_TPM2B;
buf->length = 2;
buf->capacity = buf_size - sizeof(*buf);
- buf->handles = 0;
buf->data[0] = 0;
buf->data[1] = 0;
}
@@ -177,29 +175,6 @@ 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
- * @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_buf *buf, u32 handle)
-{
- if (buf->flags & TPM_BUF_INVALID)
- return;
-
- if (buf->flags & TPM_BUF_TPM2B) {
- WARN(1, "tpm-buf: invalid type: TPM2B\n");
- buf->flags |= TPM_BUF_INVALID;
- return;
- }
-
- tpm_buf_append_u32(buf, handle);
- buf->handles++;
-}
-
/**
* tpm_buf_read() - Read from a TPM buffer
* @buf: &tpm_buf instance
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 436ee82620e4..bc50d6b734cf 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -205,7 +205,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
return rc;
tpm_buf_append_hmac_session(chip, buf, 0, NULL, 0);
} else {
- tpm_buf_append_handle(buf, pcr_idx);
+ tpm_buf_append_u32(buf, pcr_idx);
tpm_buf_append_auth(chip, buf, NULL, 0);
}
@@ -281,10 +281,8 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
TPM2_SA_CONTINUE_SESSION,
NULL, 0);
} else {
- offset = buf->handles * 4 + TPM_HEADER_SIZE;
head = (struct tpm_header *)buf->data;
- if (tpm_buf_length(buf) == offset)
- head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
+ head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
}
tpm_buf_append_u16(buf, num_bytes);
err = tpm_buf_fill_hmac_session(chip, buf);
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 62a200ae72d7..f2b8ca893e15 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -261,7 +261,7 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}
if (!tpm2_chip_auth(chip)) {
- tpm_buf_append_handle(buf, handle);
+ tpm_buf_append_u32(buf, handle);
return 0;
}
@@ -288,17 +288,7 @@ 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 9f684fc7ae04..e68995df8796 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -395,7 +395,6 @@ enum tpm_buf_flags {
*/
struct tpm_buf {
u8 flags;
- u8 handles;
u16 length;
u16 capacity;
u8 data[];
@@ -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_buf *buf, u32 handle);
/*
* Check if TPM device is in the firmware upgrade mode.
--
2.52.0
^ permalink raw reply related
* [PATCH v3 6/7] tpm: Orchestrate TPM commands in tpm_get_random()
From: Jarkko Sakkinen @ 2025-12-10 14:39 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210143940.264191-1-jarkko@kernel.org>
tpm1_get_random() and tpm2_get_random() contain duplicate orchestration
code. Consolidate orchestration to tpm_get_random().
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
drivers/char/tpm/tpm-interface.c | 165 ++++++++++++++++++++++++++++---
drivers/char/tpm/tpm.h | 2 -
drivers/char/tpm/tpm1-cmd.c | 62 ------------
drivers/char/tpm/tpm2-cmd.c | 95 ------------------
4 files changed, 154 insertions(+), 170 deletions(-)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index f745a098908b..ab52a1cb0a78 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -26,7 +26,7 @@
#include <linux/suspend.h>
#include <linux/freezer.h>
#include <linux/tpm_eventlog.h>
-
+#include <linux/tpm_command.h>
#include "tpm.h"
/*
@@ -486,19 +486,143 @@ int tpm_pm_resume(struct device *dev)
}
EXPORT_SYMBOL_GPL(tpm_pm_resume);
+struct tpm1_get_random_out {
+ __be32 rng_data_len;
+ u8 rng_data[TPM_MAX_RNG_DATA];
+} __packed;
+
+static int tpm1_get_random(struct tpm_chip *chip, u8 *out, size_t max)
+{
+ struct tpm1_get_random_out *resp;
+ u32 recd;
+ int rc;
+
+ if (!out || !max || max > TPM_MAX_RNG_DATA)
+ return -EINVAL;
+
+ 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_GETRANDOM);
+ tpm_buf_append_u32(buf, max);
+
+ rc = tpm_transmit_cmd(chip, buf, sizeof(resp->rng_data_len), "TPM_GetRandom");
+ if (rc) {
+ if (rc > 0)
+ rc = -EIO;
+ return rc;
+ }
+
+ resp = (struct tpm1_get_random_out *)&buf->data[TPM_HEADER_SIZE];
+
+ recd = be32_to_cpu(resp->rng_data_len);
+ if (recd > max)
+ return -EIO;
+
+ if (buf->length < TPM_HEADER_SIZE + sizeof(resp->rng_data_len) + recd)
+ return -EIO;
+
+ memcpy(out, resp->rng_data, recd);
+ return recd;
+}
+
+struct tpm2_get_random_out {
+ __be16 size;
+ u8 buffer[TPM_MAX_RNG_DATA];
+} __packed;
+
+static int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
+{
+ struct tpm2_get_random_out *resp;
+ struct tpm_header *head;
+ off_t offset;
+ u32 recd;
+ int ret;
+
+ if (!out || !max || max > TPM_MAX_RNG_DATA)
+ return -EINVAL;
+
+ 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_SESSIONS, TPM2_CC_GET_RANDOM);
+ if (tpm2_chip_auth(chip)) {
+ tpm_buf_append_hmac_session(chip, buf,
+ TPM2_SA_ENCRYPT | TPM2_SA_CONTINUE_SESSION,
+ NULL, 0);
+ } else {
+ head = (struct tpm_header *)buf->data;
+ head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
+ }
+ tpm_buf_append_u16(buf, max);
+
+ ret = tpm_buf_fill_hmac_session(chip, buf);
+ if (ret)
+ return ret;
+
+ ret = tpm_transmit_cmd(chip, buf, offsetof(struct tpm2_get_random_out, buffer),
+ "TPM2_GetRandom");
+
+ ret = tpm_buf_check_hmac_response(chip, buf, ret);
+ if (ret) {
+ if (ret > 0)
+ ret = -EIO;
+
+ goto out;
+ }
+
+ 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];
+ recd = min_t(u32, be16_to_cpu(resp->size), max);
+
+ if (tpm_buf_length(buf) <
+ TPM_HEADER_SIZE + offsetof(struct tpm2_get_random_out, buffer) + recd) {
+ ret = -EIO;
+ goto out;
+ }
+
+ memcpy(out, resp->buffer, recd);
+ return recd;
+
+out:
+ tpm2_end_auth_session(chip);
+ return ret;
+}
+
/**
- * tpm_get_random() - get random bytes from the TPM's RNG
- * @chip: a &struct tpm_chip instance, %NULL for the default chip
- * @out: destination buffer for the random bytes
- * @max: the max number of bytes to write to @out
+ * tpm_get_random() - Get random bytes from the TPM's RNG
+ * @chip: A &tpm_chip instance. Whenset to %NULL, the default chip is used.
+ * @out: Destination buffer for the acquired random bytes.
+ * @max: The maximum number of bytes to write to @out.
*
- * Return: number of random bytes read or a negative error value.
+ * Iterates pulling more bytes from TPM up until all of the @max bytes have been
+ * received.
+ *
+ * Returns the number of random bytes read on success.
+ * Returns -EINVAL when @out is NULL, or @max is not between zero and
+ * %TPM_MAX_RNG_DATA.
+ * Returns tpm_transmit_cmd() error codes when the TPM command results an
+ * error.
*/
int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
{
+ u32 num_bytes = max;
+ u8 *out_ptr = out;
+ int retries = 5;
+ int total = 0;
int rc;
- if (!out || max > TPM_MAX_RNG_DATA)
+ if (!out || !max || max > TPM_MAX_RNG_DATA)
return -EINVAL;
if (!chip)
@@ -508,11 +632,30 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
if (rc)
return rc;
- if (chip->flags & TPM_CHIP_FLAG_TPM2)
- rc = tpm2_get_random(chip, out, max);
- else
- rc = tpm1_get_random(chip, out, max);
+ if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+ rc = tpm2_start_auth_session(chip);
+ if (rc)
+ return rc;
+ }
+
+ do {
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ rc = tpm2_get_random(chip, out_ptr, num_bytes);
+ else
+ rc = tpm1_get_random(chip, out_ptr, num_bytes);
+
+ if (rc < 0)
+ goto err;
+
+ out_ptr += rc;
+ total += rc;
+ num_bytes -= rc;
+ } while (retries-- && total < max);
+
+ tpm_put_ops(chip);
+ return total ? total : -EIO;
+err:
tpm_put_ops(chip);
return rc;
}
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 5395927c62fc..c4bbd8f04605 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -250,7 +250,6 @@ int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
const char *desc, size_t min_cap_length);
-int tpm1_get_random(struct tpm_chip *chip, u8 *out, size_t max);
int tpm1_get_pcr_allocation(struct tpm_chip *chip);
unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
int tpm_pm_suspend(struct device *dev);
@@ -290,7 +289,6 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digest, u16 *digest_size_ptr);
int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digests);
-int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,
u32 *value, const char *desc);
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 11090053ef54..d8f16e66666b 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -502,68 +502,6 @@ ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
}
EXPORT_SYMBOL_GPL(tpm1_getcap);
-#define TPM_ORD_GET_RANDOM 70
-struct tpm1_get_random_out {
- __be32 rng_data_len;
- u8 rng_data[TPM_MAX_RNG_DATA];
-} __packed;
-
-/**
- * tpm1_get_random() - get random bytes from the TPM's RNG
- * @chip: a &struct tpm_chip instance
- * @dest: destination buffer for the random bytes
- * @max: the maximum number of bytes to write to @dest
- *
- * Return:
- * * number of bytes read
- * * -errno (positive TPM return codes are masked to -EIO)
- */
-int tpm1_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
-{
- struct tpm1_get_random_out *out;
- u32 num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA);
- u32 total = 0;
- int retries = 5;
- u32 recd;
- int rc;
-
- struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- tpm_buf_init(buf, TPM_BUFSIZE);
- do {
- tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_GET_RANDOM);
- tpm_buf_append_u32(buf, num_bytes);
-
- rc = tpm_transmit_cmd(chip, buf, sizeof(out->rng_data_len), "TPM_GetRandom");
- if (rc) {
- if (rc > 0)
- rc = -EIO;
- return rc;
- }
-
- out = (struct tpm1_get_random_out *)&buf->data[TPM_HEADER_SIZE];
-
- recd = be32_to_cpu(out->rng_data_len);
- if (recd > num_bytes)
- return -EFAULT;
-
- if (buf->length < TPM_HEADER_SIZE +
- sizeof(out->rng_data_len) + recd)
- return -EFAULT;
-
- memcpy(dest, out->rng_data, recd);
-
- dest += recd;
- total += recd;
- num_bytes -= recd;
- } while (retries-- && total < max);
-
- rc = total ? (int)total : -EIO;
- return rc;
-}
-
#define TPM_ORD_PCRREAD 21
int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
{
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index bc50d6b734cf..f066efb54a2c 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -233,101 +233,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
return rc;
}
-struct tpm2_get_random_out {
- __be16 size;
- u8 buffer[TPM_MAX_RNG_DATA];
-} __packed;
-
-/**
- * tpm2_get_random() - get random bytes from the TPM RNG
- *
- * @chip: a &tpm_chip instance
- * @dest: destination buffer
- * @max: the max number of random bytes to pull
- *
- * Return:
- * size of the buffer on success,
- * -errno otherwise (positive TPM return codes are masked to -EIO)
- */
-int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
-{
- struct tpm2_get_random_out *out;
- struct tpm_header *head;
- u32 recd;
- u32 num_bytes = max;
- int err;
- int total = 0;
- int retries = 5;
- u8 *dest_ptr = dest;
- off_t offset;
-
- if (!num_bytes || max > TPM_MAX_RNG_DATA)
- return -EINVAL;
-
- struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- err = tpm2_start_auth_session(chip);
- if (err)
- return err;
-
- tpm_buf_init(buf, TPM_BUFSIZE);
- do {
- tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_GET_RANDOM);
- if (tpm2_chip_auth(chip)) {
- tpm_buf_append_hmac_session(chip, buf,
- TPM2_SA_ENCRYPT |
- TPM2_SA_CONTINUE_SESSION,
- NULL, 0);
- } else {
- head = (struct tpm_header *)buf->data;
- head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
- }
- tpm_buf_append_u16(buf, num_bytes);
- 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),
- "TPM2_GetRandom");
- err = tpm_buf_check_hmac_response(chip, buf, err);
- if (err) {
- if (err > 0)
- err = -EIO;
- goto out;
- }
-
- 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;
-
- out = (struct tpm2_get_random_out *)&buf->data[offset];
- recd = min_t(u32, be16_to_cpu(out->size), num_bytes);
- if (tpm_buf_length(buf) <
- TPM_HEADER_SIZE +
- offsetof(struct tpm2_get_random_out, buffer) +
- recd) {
- err = -EFAULT;
- goto out;
- }
- memcpy(dest_ptr, out->buffer, recd);
-
- dest_ptr += recd;
- total += recd;
- num_bytes -= recd;
- } while (retries-- && total < max);
-
- return total ? total : -EIO;
-out:
- tpm2_end_auth_session(chip);
- return err;
-}
-
/**
* tpm2_flush_context() - execute a TPM2_FlushContext command
* @chip: TPM chip to use
--
2.52.0
^ permalink raw reply related
* [PATCH v3 7/7] tpm: Send only one TPM command per hwrng request
From: Jarkko Sakkinen @ 2025-12-10 14:39 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, David S. Miller, Herbert Xu, Peter Huewe,
Jason Gunthorpe, David Howells, Paul Moore, James Morris,
Serge E. Hallyn, James Bottomley, Mimi Zohar, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210143940.264191-1-jarkko@kernel.org>
hwrng framework does not have a enforce that all bytes requested need to be
read. By enforcing such a requirement internally, TPM driver can cause
unpredicatability in latency, as a single tpm_get_random() call can result
multiple TPM commands.
Especially, when TCG_TPM2_HMAC is enabled, roundtrips with the TPM should
be capped to exactly one.
Add a @wait parameter to enforce this behavior and set it to true at the
call sites TPM 1.2 keys. At the call sites of hwrng, set @wait to false.
Cc: David S. Miller <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
drivers/char/tpm/tpm-chip.c | 2 +-
drivers/char/tpm/tpm-interface.c | 11 +++++++++--
include/linux/tpm.h | 2 +-
security/keys/trusted-keys/trusted_tpm1.c | 8 ++++----
4 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 082b910ddf0d..8fca4373e2df 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -494,7 +494,7 @@ static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
{
struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng);
- return tpm_get_random(chip, data, max);
+ return tpm_get_random(chip, data, max, false);
}
static bool tpm_is_hwrng_enabled(struct tpm_chip *chip)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index ab52a1cb0a78..5cc2bbabd57a 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -604,9 +604,11 @@ static int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
* @chip: A &tpm_chip instance. Whenset to %NULL, the default chip is used.
* @out: Destination buffer for the acquired random bytes.
* @max: The maximum number of bytes to write to @out.
+ * @wait: Set to true when all of the @max bytes need to be acquired.
*
* Iterates pulling more bytes from TPM up until all of the @max bytes have been
- * received.
+ * received, when @wait it sets true. Otherwise, the queries for @max bytes from
+ * TPM exactly once, and returns the bytes that were received.
*
* Returns the number of random bytes read on success.
* Returns -EINVAL when @out is NULL, or @max is not between zero and
@@ -614,7 +616,7 @@ static int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
* Returns tpm_transmit_cmd() error codes when the TPM command results an
* error.
*/
-int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
+int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max, bool wait)
{
u32 num_bytes = max;
u8 *out_ptr = out;
@@ -647,6 +649,11 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
if (rc < 0)
goto err;
+ if (!wait) {
+ total = rc;
+ break;
+ }
+
out_ptr += rc;
total += rc;
num_bytes -= rc;
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index e68995df8796..177833d6b965 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -485,7 +485,7 @@ extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digest);
extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digests);
-extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
+int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max, bool wait);
extern struct tpm_chip *tpm_default_chip(void);
void tpm2_flush_context(struct tpm_chip *chip, u32 handle);
int tpm2_find_hash_alg(unsigned int crypto_id);
diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c
index 759c1ecb0435..f36f6a0b533f 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -361,7 +361,7 @@ static int osap(struct tpm_buf *tb, struct osapsess *s,
unsigned char ononce[TPM_NONCE_SIZE];
int ret;
- ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE);
+ ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE, true);
if (ret < 0)
return ret;
@@ -454,7 +454,7 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
- ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE);
+ ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE, true);
if (ret < 0)
goto out;
@@ -565,7 +565,7 @@ static int tpm_unseal(struct tpm_buf *tb,
}
ordinal = htonl(TPM_ORD_UNSEAL);
- ret = tpm_get_random(chip, nonceodd, TPM_NONCE_SIZE);
+ ret = tpm_get_random(chip, nonceodd, TPM_NONCE_SIZE, true);
if (ret < 0)
return ret;
@@ -938,7 +938,7 @@ static int trusted_tpm_unseal(struct trusted_key_payload *p, char *datablob)
static int trusted_tpm_get_random(unsigned char *key, size_t key_len)
{
- return tpm_get_random(chip, key, key_len);
+ return tpm_get_random(chip, key, key_len, true);
}
static int __init init_digests(void)
--
2.52.0
^ permalink raw reply related
* [PATCH v4 0/8] Streamline TPM2 HMAC sessions
From: Jarkko Sakkinen @ 2025-12-10 17:20 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, David Howells, Paul Moore, James Morris,
Serge E. Hallyn, open list:KEYS/KEYRINGS,
open list:SECURITY SUBSYSTEM, open list
Since we cannot at this point cache names of the keys given limitations
of the ASN.1 file format, I'll start a fresh patch set. Let's fixup what
we can right now.
This patch set addresses two major issues in the feature:
1. Dynamic resolution without gain. All kernel sites have at most single
handle to authorize. Even if this changes some day this is how it is
as of today and we definitely do not want to dictate the future but
instead downscale code to the metrics that we have as of today.
2. Eliminate at least one unnnecessary tpm2_read_public() call.
Jarkko Sakkinen (8):
KEYS: trusted: Remove dead branch from tpm2_unseal_cmd
tpm2-sessions: Define TPM2_NAME_MAX_SIZE
KEYS: trusted: Re-orchestrate tpm2_read_public() calls
tpm2-sessions: Remove AUTH_MAX_NAMES
tpm-buf: Remove tpm_buf_append_handle
tpm: Orchestrate TPM commands in tpm_get_random()
tpm: Send only one at most TPM2_GetRandom command
tpm: In tpm_get_random() replace 'retries' with a zero check
drivers/char/tpm/tpm-buf.c | 25 ---
drivers/char/tpm/tpm-chip.c | 2 +-
drivers/char/tpm/tpm-interface.c | 177 ++++++++++++++++++++--
drivers/char/tpm/tpm-sysfs.c | 2 +-
drivers/char/tpm/tpm.h | 2 -
drivers/char/tpm/tpm1-cmd.c | 62 --------
drivers/char/tpm/tpm2-cmd.c | 102 +------------
drivers/char/tpm/tpm2-sessions.c | 130 +++++-----------
include/linux/tpm.h | 51 +++++--
security/keys/trusted-keys/trusted_tpm1.c | 8 +-
security/keys/trusted-keys/trusted_tpm2.c | 134 +++++++++-------
11 files changed, 325 insertions(+), 370 deletions(-)
--
2.39.5
^ permalink raw reply
* [PATCH v4 1/8] KEYS: trusted: Remove dead branch from tpm2_unseal_cmd
From: Jarkko Sakkinen @ 2025-12-10 17:20 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, David Howells, Paul Moore, James Morris,
Serge E. Hallyn, James Bottomley, Mimi Zohar,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM, open list
In-Reply-To: <20251210172027.109938-1-jarkko@kernel.org>
TPM2_Unseal requires TPM2_ST_SESSIONS, and tpm2_unseal_cmd() always does
set up either password or HMAC session.
Remove the branch in tpm2_unseal_cmd() conditionally setting
TPM2_ST_NO_SESSIONS. It is faulty but luckily it is never exercised at
run-time, and thus does not cause regressions.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
security/keys/trusted-keys/trusted_tpm2.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 9074ae1a5896..27424e1a4a63 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -450,9 +450,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
struct trusted_key_options *options,
u32 blob_handle)
{
- struct tpm_header *head;
u16 data_len;
- int offset;
u8 *data;
int rc;
@@ -488,14 +486,8 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
tpm_buf_append_u16(buf, options->blobauth_len);
tpm_buf_append(buf, options->blobauth, options->blobauth_len);
- if (tpm2_chip_auth(chip)) {
+ if (tpm2_chip_auth(chip))
tpm_buf_append_hmac_session(chip, buf, TPM2_SA_ENCRYPT, NULL, 0);
- } else {
- offset = buf->handles * 4 + TPM_HEADER_SIZE;
- head = (struct tpm_header *)buf->data;
- if (tpm_buf_length(buf) == offset)
- head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
- }
}
rc = tpm_buf_fill_hmac_session(chip, buf);
--
2.39.5
^ permalink raw reply related
* [PATCH v4 2/8] tpm2-sessions: Define TPM2_NAME_MAX_SIZE
From: Jarkko Sakkinen @ 2025-12-10 17:20 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210172027.109938-1-jarkko@kernel.org>
This is somewhat cosmetic change but it does serve a purpose on tracking
the value set for the maximum length of TPM names, and to clearly states
what components it is composed of. It also anchors the value so that when
buffers are declared for this particular purpose, the same value is used
for the capacity.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v2:
- Rename TPM2_NAME_SIZE as TPM2_NULL_NAME_SIZE.
---
drivers/char/tpm/tpm-sysfs.c | 2 +-
drivers/char/tpm/tpm2-sessions.c | 2 +-
include/linux/tpm.h | 37 +++++++++++++++++++++-----------
3 files changed, 27 insertions(+), 14 deletions(-)
diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index f5dcadb1ab3c..0f321c307bc6 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -313,7 +313,7 @@ static ssize_t null_name_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct tpm_chip *chip = to_tpm_chip(dev);
- int size = TPM2_NAME_SIZE;
+ int size = TPM2_NULL_NAME_SIZE;
bin2hex(buf, chip->null_key_name, size);
size *= 2;
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 79f27a46bd7f..a0c88fb1804c 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -137,7 +137,7 @@ struct tpm2_auth {
* we must compute and remember
*/
u32 name_h[AUTH_MAX_NAMES];
- u8 name[AUTH_MAX_NAMES][2 + SHA512_DIGEST_SIZE];
+ u8 name[AUTH_MAX_NAMES][TPM2_MAX_NAME_SIZE];
};
#ifdef CONFIG_TCG_TPM2_HMAC
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 42e2a091f43d..922a43ef23b5 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -28,9 +28,33 @@
#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.
+ */
#define TPM2_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE
+
+/*
+ * A TPM name digest i.e., TPMT_HA, is a concatenation of TPM_ALG_ID of the
+ * name algorithm and hash of TPMT_PUBLIC.
+ */
+#define TPM2_MAX_NAME_SIZE (TPM2_MAX_DIGEST_SIZE + 2)
+
+/*
+ * The maximum number of PCR banks.
+ */
#define TPM2_MAX_PCR_BANKS 8
+/*
+ * fixed define for the size of a name. This is actually HASHALG size
+ * plus 2, so 32 for SHA256
+ */
+#define TPM2_NULL_NAME_SIZE 34
+
+/*
+ * The maximum size for an object context
+ */
+#define TPM2_MAX_CONTEXT_SIZE 4096
+
struct tpm_chip;
struct trusted_key_payload;
struct trusted_key_options;
@@ -140,17 +164,6 @@ struct tpm_chip_seqops {
/* fixed define for the curve we use which is NIST_P256 */
#define EC_PT_SZ 32
-/*
- * fixed define for the size of a name. This is actually HASHALG size
- * plus 2, so 32 for SHA256
- */
-#define TPM2_NAME_SIZE 34
-
-/*
- * The maximum size for an object context
- */
-#define TPM2_MAX_CONTEXT_SIZE 4096
-
struct tpm_chip {
struct device dev;
struct device devs;
@@ -212,7 +225,7 @@ struct tpm_chip {
/* saved context for NULL seed */
u8 null_key_context[TPM2_MAX_CONTEXT_SIZE];
/* name of NULL seed */
- u8 null_key_name[TPM2_NAME_SIZE];
+ u8 null_key_name[TPM2_NULL_NAME_SIZE];
u8 null_ec_key_x[EC_PT_SZ];
u8 null_ec_key_y[EC_PT_SZ];
struct tpm2_auth *auth;
--
2.39.5
^ permalink raw reply related
* [PATCH v4 3/8] KEYS: trusted: Re-orchestrate tpm2_read_public() calls
From: Jarkko Sakkinen @ 2025-12-10 17:20 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, James Bottomley,
Mimi Zohar, open list, open list:KEYS/KEYRINGS,
open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210172027.109938-1-jarkko@kernel.org>
tpm2_load_cmd() and tpm2_unseal_cmd() use the same parent, and calls to
tpm_buf_append_name() cause the exact same TPM2_ReadPublic command to be
sent to the chip, causing unnecessary traffic.
1. Export tpm2_read_public in order to make it callable from
'trusted_tpm2'.
2. Re-orchestrate tpm2_seal_trusted() and tpm2_unseal_trusted() in order to
halve the name resolutions required:
2a. Move tpm2_read_public() calls into trusted_tpm2.
2b. Pass TPM name to tpm_buf_append_name().
2c. Rework tpm_buf_append_name() to use the pre-resolved name.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
drivers/char/tpm/tpm2-cmd.c | 3 +-
drivers/char/tpm/tpm2-sessions.c | 95 +++++------------
include/linux/tpm.h | 10 +-
security/keys/trusted-keys/trusted_tpm2.c | 124 ++++++++++++++--------
4 files changed, 118 insertions(+), 114 deletions(-)
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 543c1c62c938..436ee82620e4 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -199,7 +199,8 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
if (!disable_pcr_integrity) {
- rc = tpm_buf_append_name(chip, buf, pcr_idx, NULL);
+ rc = tpm_buf_append_name(chip, buf, pcr_idx, (u8 *)&pcr_idx,
+ sizeof(u32));
if (rc)
return rc;
tpm_buf_append_hmac_session(chip, buf, 0, NULL, 0);
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index a0c88fb1804c..0816a91134fc 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -136,8 +136,8 @@ struct tpm2_auth {
* handle, but they are part of the session by name, which
* we must compute and remember
*/
- u32 name_h[AUTH_MAX_NAMES];
u8 name[AUTH_MAX_NAMES][TPM2_MAX_NAME_SIZE];
+ u16 name_size_tbl[AUTH_MAX_NAMES];
};
#ifdef CONFIG_TCG_TPM2_HMAC
@@ -163,7 +163,17 @@ static int name_size(const u8 *name)
}
}
-static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
+/**
+ * tpm2_read_public: Resolve TPM name for a handle
+ * @chip: TPM chip to use.
+ * @handle: TPM handle.
+ * @name: A buffer for returning the name blob. Must have a
+ * capacity of 'SHA512_DIGET_SIZE + 2' bytes at minimum
+ *
+ * Returns size of TPM handle name of success.
+ * Returns tpm_transmit_cmd error codes when TPM2_ReadPublic fails.
+ */
+int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
{
u32 mso = tpm2_handle_mso(handle);
off_t offset = TPM_HEADER_SIZE;
@@ -212,14 +222,16 @@ static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
memcpy(name, &buf->data[offset], rc);
return name_size_alg;
}
+EXPORT_SYMBOL_GPL(tpm2_read_public);
#endif /* CONFIG_TCG_TPM2_HMAC */
/**
- * tpm_buf_append_name() - add a handle area to the buffer
- * @chip: the TPM chip structure
- * @buf: The buffer to be appended
- * @handle: The handle to be appended
- * @name: The name of the handle (may be NULL)
+ * tpm_buf_append_name() - Append a handle and store TPM name
+ * @chip: TPM chip to use.
+ * @buf: TPM buffer containing the TPM command in-transit.
+ * @handle: TPM handle to be appended.
+ * @name: TPM name of the handle
+ * @name_size: Size of the TPM name.
*
* In order to compute session HMACs, we need to know the names of the
* objects pointed to by the handles. For most objects, this is simply
@@ -236,15 +248,14 @@ static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
* will be caused by an incorrect programming model and indicated by a
* kernel message.
*
- * Ends the authorization session on failure.
+ * Returns zero on success.
+ * Returns -EIO when the authorization area state is malformed.
*/
int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
- u32 handle, u8 *name)
+ u32 handle, u8 *name, u16 name_size)
{
#ifdef CONFIG_TCG_TPM2_HMAC
- enum tpm2_mso_type mso = tpm2_handle_mso(handle);
struct tpm2_auth *auth;
- u16 name_size_alg;
int slot;
int ret;
#endif
@@ -269,36 +280,15 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}
tpm_buf_append_u32(buf, handle);
auth->session += 4;
-
- if (mso == TPM2_MSO_PERSISTENT ||
- mso == TPM2_MSO_VOLATILE ||
- mso == TPM2_MSO_NVRAM) {
- if (!name) {
- ret = tpm2_read_public(chip, handle, auth->name[slot]);
- if (ret < 0)
- goto err;
-
- name_size_alg = ret;
- }
- } else {
- if (name) {
- dev_err(&chip->dev, "handle 0x%08x does not use a name\n",
- handle);
- ret = -EIO;
- goto err;
- }
- }
-
- auth->name_h[slot] = handle;
- if (name)
- memcpy(auth->name[slot], name, name_size_alg);
+ memcpy(auth->name[slot], name, name_size);
+ auth->name_size_tbl[slot] = name_size;
#endif
return 0;
#ifdef CONFIG_TCG_TPM2_HMAC
err:
tpm2_end_auth_session(chip);
- return tpm_ret_to_err(ret);
+ return ret;
#endif
}
EXPORT_SYMBOL_GPL(tpm_buf_append_name);
@@ -606,22 +596,8 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
attrs = chip->cc_attrs_tbl[i];
handles = (attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0);
+ offset_s += handles * sizeof(u32);
- /*
- * just check the names, it's easy to make mistakes. This
- * would happen if someone added a handle via
- * tpm_buf_append_u32() instead of tpm_buf_append_name()
- */
- for (i = 0; i < handles; i++) {
- u32 handle = tpm_buf_read_u32(buf, &offset_s);
-
- if (auth->name_h[i] != handle) {
- dev_err(&chip->dev, "invalid handle 0x%08x\n", handle);
- ret = -EIO;
- goto err;
- }
- }
- /* point offset_s to the start of the sessions */
val = tpm_buf_read_u32(buf, &offset_s);
/* point offset_p to the start of the parameters */
offset_p = offset_s + val;
@@ -682,23 +658,8 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
/* ordinal is already BE */
sha256_update(&sctx, (u8 *)&head->ordinal, sizeof(head->ordinal));
/* add the handle names */
- for (i = 0; i < handles; i++) {
- enum tpm2_mso_type mso = tpm2_handle_mso(auth->name_h[i]);
-
- if (mso == TPM2_MSO_PERSISTENT ||
- mso == TPM2_MSO_VOLATILE ||
- mso == TPM2_MSO_NVRAM) {
- ret = name_size(auth->name[i]);
- if (ret < 0)
- goto err;
-
- sha256_update(&sctx, auth->name[i], ret);
- } else {
- __be32 h = cpu_to_be32(auth->name_h[i]);
-
- sha256_update(&sctx, (u8 *)&h, 4);
- }
- }
+ for (i = 0; i < handles; i++)
+ sha256_update(&sctx, auth->name[i], auth->name_size_tbl[i]);
if (offset_s != tpm_buf_length(buf))
sha256_update(&sctx, &buf->data[offset_s],
tpm_buf_length(buf) - offset_s);
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 922a43ef23b5..9f684fc7ae04 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -543,7 +543,7 @@ static inline struct tpm2_auth *tpm2_chip_auth(struct tpm_chip *chip)
}
int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
- u32 handle, u8 *name);
+ u32 handle, u8 *name, u16 name_size);
void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf,
u8 attributes, u8 *passphrase,
int passphraselen);
@@ -557,6 +557,7 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf);
int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf,
int rc);
void tpm2_end_auth_session(struct tpm_chip *chip);
+int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name);
#else
#include <linux/unaligned.h>
@@ -580,6 +581,13 @@ static inline int tpm_buf_check_hmac_response(struct tpm_chip *chip,
{
return rc;
}
+
+static inline int tpm2_read_public(struct tpm_chip *chip, u32 handle,
+ void *name)
+{
+ memcpy(name, &handle, sizeof(u32));
+ return sizeof(u32);
+}
#endif /* CONFIG_TCG_TPM2_HMAC */
#endif
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 27424e1a4a63..63539b344ffb 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -203,7 +203,9 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options)
{
+ u8 parent_name[TPM2_MAX_NAME_SIZE];
off_t offset = TPM_HEADER_SIZE;
+ u16 parent_name_size;
int blob_len = 0;
int hash;
u32 flags;
@@ -220,6 +222,12 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
if (rc)
return rc;
+ rc = tpm2_read_public(chip, options->keyhandle, parent_name);
+ if (rc < 0)
+ goto out_put;
+
+ parent_name_size = rc;
+
rc = tpm2_start_auth_session(chip);
if (rc)
goto out_put;
@@ -234,7 +242,8 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
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, NULL);
+ rc = tpm_buf_append_name(chip, buf, options->keyhandle, parent_name,
+ parent_name_size);
if (rc)
goto out_put;
@@ -326,48 +335,38 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
}
/**
- * tpm2_load_cmd() - execute a TPM2_Load command
- *
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- * @blob_handle: returned blob handle
+ * tpm2_load_cmd() - Execute TPM2_Load
+ * @chip: TPM chip to use.
+ * @payload: Key data in clear text.
+ * @options: Trusted key options.
+ * @parent_name: A cryptographic name, i.e. a TPMT_HA blob, of the
+ * parent key.
+ * @blob: The decoded payload for the key.
+ * @blob_handle: On success, will contain handle to the loaded keyedhash
+ * blob.
*
- * Return: 0 on success.
- * -E2BIG on wrong payload size.
- * -EPERM on tpm error status.
- * < 0 error from tpm_send.
+ * Return -E2BIG when the blob size is too small for all the data.
+ * Returns tpm_transmit_cmd() error codes when either TPM2_Load fails.
*/
static int tpm2_load_cmd(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options,
+ u8 *parent_name,
+ u16 parent_name_size,
+ const u8 *blob,
u32 *blob_handle)
{
u8 *blob_ref __free(kfree) = NULL;
unsigned int private_len;
unsigned int public_len;
unsigned int blob_len;
- u8 *blob, *pub;
+ const u8 *pub;
int rc;
u32 attrs;
- rc = tpm2_key_decode(payload, options, &blob);
- if (rc) {
- /* old form */
- blob = payload->blob;
- payload->old_format = 1;
- } else {
- /* Bind for cleanup: */
- blob_ref = blob;
- }
-
- /* new format carries keyhandle but old format doesn't */
- if (!options->keyhandle)
- return -EINVAL;
-
/* must be big enough for at least the two be16 size counts */
if (payload->blob_len < 4)
- return -EINVAL;
+ return -E2BIG;
private_len = get_unaligned_be16(blob);
@@ -406,7 +405,8 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
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, NULL);
+ rc = tpm_buf_append_name(chip, buf, options->keyhandle, parent_name,
+ parent_name_size);
if (rc)
return rc;
@@ -434,20 +434,23 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
}
/**
- * tpm2_unseal_cmd() - execute a TPM2_Unload command
+ * tpm2_unseal_cmd() - Execute TPM2_Unload
*
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- * @blob_handle: blob handle
+ * @chip: TPM chip to use
+ * @payload: Key data in clear text.
+ * @options: Trusted key options.
+ * @parent_name: A cryptographic name, i.e. a TPMT_HA blob, of the
+ * parent key.
+ * @blob_handle: Handle to the loaded keyedhash blob.
*
- * Return: 0 on success
- * -EPERM on tpm error status
- * < 0 error from tpm_send
+ * Return -E2BIG when the blob size is too small for all the data.
+ * Returns tpm_transmit_cmd() error codes when either TPM2_Load fails.
*/
static int tpm2_unseal_cmd(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options,
+ u8 *parent_name,
+ u16 parent_name_size,
u32 blob_handle)
{
u16 data_len;
@@ -465,7 +468,8 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
tpm_buf_init(buf, TPM_BUFSIZE);
tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
- rc = tpm_buf_append_name(chip, buf, options->keyhandle, NULL);
+ rc = tpm_buf_append_name(chip, buf, options->keyhandle, parent_name,
+ parent_name_size);
if (rc)
return rc;
@@ -526,30 +530,60 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
}
/**
- * tpm2_unseal_trusted() - unseal the payload of a trusted key
+ * tpm2_unseal_trusted() - Unseal a trusted key
+ * @chip: TPM chip to use.
+ * @payload: Key data in clear text.
+ * @options: Trusted key options.
*
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- *
- * Return: Same as with tpm_send.
+ * Return -E2BIG when the blob size is too small for all the data.
+ * Return -EINVAL when parent's key handle has not been set.
+ * Returns tpm_transmit_cmd() error codes when either TPM2_Load or TPM2_Unseal
+ * fails.
*/
int tpm2_unseal_trusted(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options)
{
+ u8 *blob_ref __free(kfree) = NULL;
+ u8 parent_name[TPM2_MAX_NAME_SIZE];
+ u16 parent_name_size;
u32 blob_handle;
+ u8 *blob;
int rc;
+ /*
+ * Try to decode the provided blob as an ASN.1 blob. Assume that the
+ * blob is in the legacy format if decoding does not end successfully.
+ */
+ rc = tpm2_key_decode(payload, options, &blob);
+ if (rc) {
+ blob = payload->blob;
+ payload->old_format = 1;
+ } else {
+ blob_ref = blob;
+ }
+
+ if (!options->keyhandle)
+ return -EINVAL;
+
rc = tpm_try_get_ops(chip);
if (rc)
return rc;
- rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
+ rc = tpm2_read_public(chip, options->keyhandle, parent_name);
+ if (rc < 0)
+ goto out;
+
+ parent_name_size = rc;
+
+ rc = tpm2_load_cmd(chip, payload, options, parent_name,
+ parent_name_size, blob, &blob_handle);
if (rc)
goto out;
- rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
+ rc = tpm2_unseal_cmd(chip, payload, options, parent_name,
+ parent_name_size, blob_handle);
+
tpm2_flush_context(chip, blob_handle);
out:
--
2.39.5
^ permalink raw reply related
* [PATCH v4 4/8] tpm2-sessions: Remove AUTH_MAX_NAMES
From: Jarkko Sakkinen @ 2025-12-10 17:20 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210172027.109938-1-jarkko@kernel.org>
In all of the call sites only one session is ever append. Thus, reduce
AUTH_MAX_NAMES, which leads into removing constant completely.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
drivers/char/tpm/tpm2-sessions.c | 31 +++++++++++--------------------
1 file changed, 11 insertions(+), 20 deletions(-)
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 0816a91134fc..62a200ae72d7 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -72,9 +72,6 @@
#include <crypto/sha2.h>
#include <crypto/utils.h>
-/* maximum number of names the TPM must remember for authorization */
-#define AUTH_MAX_NAMES 3
-
#define AES_KEY_BYTES AES_KEYSIZE_128
#define AES_KEY_BITS (AES_KEY_BYTES*8)
@@ -136,8 +133,8 @@ struct tpm2_auth {
* handle, but they are part of the session by name, which
* we must compute and remember
*/
- u8 name[AUTH_MAX_NAMES][TPM2_MAX_NAME_SIZE];
- u16 name_size_tbl[AUTH_MAX_NAMES];
+ u8 name[TPM2_MAX_NAME_SIZE];
+ u16 name_size;
};
#ifdef CONFIG_TCG_TPM2_HMAC
@@ -254,11 +251,14 @@ EXPORT_SYMBOL_GPL(tpm2_read_public);
int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
u32 handle, u8 *name, u16 name_size)
{
-#ifdef CONFIG_TCG_TPM2_HMAC
struct tpm2_auth *auth;
- int slot;
int ret;
-#endif
+
+ if (tpm_buf_length(buf) != TPM_HEADER_SIZE) {
+ dev_err(&chip->dev, "too many handles\n");
+ ret = -EIO;
+ goto err;
+ }
if (!tpm2_chip_auth(chip)) {
tpm_buf_append_handle(buf, handle);
@@ -266,12 +266,6 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}
#ifdef CONFIG_TCG_TPM2_HMAC
- slot = (tpm_buf_length(buf) - TPM_HEADER_SIZE) / 4;
- if (slot >= AUTH_MAX_NAMES) {
- dev_err(&chip->dev, "too many handles\n");
- ret = -EIO;
- goto err;
- }
auth = chip->auth;
if (auth->session != tpm_buf_length(buf)) {
dev_err(&chip->dev, "session state malformed");
@@ -280,16 +274,14 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}
tpm_buf_append_u32(buf, handle);
auth->session += 4;
- memcpy(auth->name[slot], name, name_size);
- auth->name_size_tbl[slot] = name_size;
+ memcpy(auth->name, name, name_size);
+ auth->name_size = name_size;
#endif
return 0;
-#ifdef CONFIG_TCG_TPM2_HMAC
err:
tpm2_end_auth_session(chip);
return ret;
-#endif
}
EXPORT_SYMBOL_GPL(tpm_buf_append_name);
@@ -658,8 +650,7 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
/* ordinal is already BE */
sha256_update(&sctx, (u8 *)&head->ordinal, sizeof(head->ordinal));
/* add the handle names */
- for (i = 0; i < handles; i++)
- sha256_update(&sctx, auth->name[i], auth->name_size_tbl[i]);
+ sha256_update(&sctx, auth->name, auth->name_size);
if (offset_s != tpm_buf_length(buf))
sha256_update(&sctx, &buf->data[offset_s],
tpm_buf_length(buf) - offset_s);
--
2.39.5
^ permalink raw reply related
* [PATCH v4 5/8] tpm-buf: Remove tpm_buf_append_handle
From: Jarkko Sakkinen @ 2025-12-10 17:20 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210172027.109938-1-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 | 25 -------------------------
drivers/char/tpm/tpm2-cmd.c | 6 ++----
drivers/char/tpm/tpm2-sessions.c | 14 ++------------
include/linux/tpm.h | 2 --
4 files changed, 4 insertions(+), 43 deletions(-)
diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index 73be8a87b472..752c69b8a4f5 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -40,7 +40,6 @@ static void __tpm_buf_reset(struct tpm_buf *buf, u16 buf_size, u16 tag, u32 ordi
buf->flags = 0;
buf->length = sizeof(*head);
buf->capacity = buf_size - sizeof(*buf);
- buf->handles = 0;
head->tag = cpu_to_be16(tag);
head->length = cpu_to_be32(sizeof(*head));
head->ordinal = cpu_to_be32(ordinal);
@@ -56,7 +55,6 @@ static void __tpm_buf_reset_sized(struct tpm_buf *buf, u16 buf_size)
buf->flags = TPM_BUF_TPM2B;
buf->length = 2;
buf->capacity = buf_size - sizeof(*buf);
- buf->handles = 0;
buf->data[0] = 0;
buf->data[1] = 0;
}
@@ -177,29 +175,6 @@ 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
- * @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_buf *buf, u32 handle)
-{
- if (buf->flags & TPM_BUF_INVALID)
- return;
-
- if (buf->flags & TPM_BUF_TPM2B) {
- WARN(1, "tpm-buf: invalid type: TPM2B\n");
- buf->flags |= TPM_BUF_INVALID;
- return;
- }
-
- tpm_buf_append_u32(buf, handle);
- buf->handles++;
-}
-
/**
* tpm_buf_read() - Read from a TPM buffer
* @buf: &tpm_buf instance
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 436ee82620e4..bc50d6b734cf 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -205,7 +205,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
return rc;
tpm_buf_append_hmac_session(chip, buf, 0, NULL, 0);
} else {
- tpm_buf_append_handle(buf, pcr_idx);
+ tpm_buf_append_u32(buf, pcr_idx);
tpm_buf_append_auth(chip, buf, NULL, 0);
}
@@ -281,10 +281,8 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
TPM2_SA_CONTINUE_SESSION,
NULL, 0);
} else {
- offset = buf->handles * 4 + TPM_HEADER_SIZE;
head = (struct tpm_header *)buf->data;
- if (tpm_buf_length(buf) == offset)
- head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
+ head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
}
tpm_buf_append_u16(buf, num_bytes);
err = tpm_buf_fill_hmac_session(chip, buf);
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 62a200ae72d7..f2b8ca893e15 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -261,7 +261,7 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}
if (!tpm2_chip_auth(chip)) {
- tpm_buf_append_handle(buf, handle);
+ tpm_buf_append_u32(buf, handle);
return 0;
}
@@ -288,17 +288,7 @@ 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 9f684fc7ae04..e68995df8796 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -395,7 +395,6 @@ enum tpm_buf_flags {
*/
struct tpm_buf {
u8 flags;
- u8 handles;
u16 length;
u16 capacity;
u8 data[];
@@ -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_buf *buf, u32 handle);
/*
* Check if TPM device is in the firmware upgrade mode.
--
2.39.5
^ permalink raw reply related
* [PATCH v4 6/8] tpm: Orchestrate TPM commands in tpm_get_random()
From: Jarkko Sakkinen @ 2025-12-10 17:20 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210172027.109938-1-jarkko@kernel.org>
tpm1_get_random() and tpm2_get_random() contain duplicate orchestration
code. Consolidate orchestration to tpm_get_random().
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
drivers/char/tpm/tpm-interface.c | 165 ++++++++++++++++++++++++++++---
drivers/char/tpm/tpm.h | 2 -
drivers/char/tpm/tpm1-cmd.c | 62 ------------
drivers/char/tpm/tpm2-cmd.c | 95 ------------------
4 files changed, 154 insertions(+), 170 deletions(-)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index f745a098908b..ab52a1cb0a78 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -26,7 +26,7 @@
#include <linux/suspend.h>
#include <linux/freezer.h>
#include <linux/tpm_eventlog.h>
-
+#include <linux/tpm_command.h>
#include "tpm.h"
/*
@@ -486,19 +486,143 @@ int tpm_pm_resume(struct device *dev)
}
EXPORT_SYMBOL_GPL(tpm_pm_resume);
+struct tpm1_get_random_out {
+ __be32 rng_data_len;
+ u8 rng_data[TPM_MAX_RNG_DATA];
+} __packed;
+
+static int tpm1_get_random(struct tpm_chip *chip, u8 *out, size_t max)
+{
+ struct tpm1_get_random_out *resp;
+ u32 recd;
+ int rc;
+
+ if (!out || !max || max > TPM_MAX_RNG_DATA)
+ return -EINVAL;
+
+ 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_GETRANDOM);
+ tpm_buf_append_u32(buf, max);
+
+ rc = tpm_transmit_cmd(chip, buf, sizeof(resp->rng_data_len), "TPM_GetRandom");
+ if (rc) {
+ if (rc > 0)
+ rc = -EIO;
+ return rc;
+ }
+
+ resp = (struct tpm1_get_random_out *)&buf->data[TPM_HEADER_SIZE];
+
+ recd = be32_to_cpu(resp->rng_data_len);
+ if (recd > max)
+ return -EIO;
+
+ if (buf->length < TPM_HEADER_SIZE + sizeof(resp->rng_data_len) + recd)
+ return -EIO;
+
+ memcpy(out, resp->rng_data, recd);
+ return recd;
+}
+
+struct tpm2_get_random_out {
+ __be16 size;
+ u8 buffer[TPM_MAX_RNG_DATA];
+} __packed;
+
+static int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
+{
+ struct tpm2_get_random_out *resp;
+ struct tpm_header *head;
+ off_t offset;
+ u32 recd;
+ int ret;
+
+ if (!out || !max || max > TPM_MAX_RNG_DATA)
+ return -EINVAL;
+
+ 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_SESSIONS, TPM2_CC_GET_RANDOM);
+ if (tpm2_chip_auth(chip)) {
+ tpm_buf_append_hmac_session(chip, buf,
+ TPM2_SA_ENCRYPT | TPM2_SA_CONTINUE_SESSION,
+ NULL, 0);
+ } else {
+ head = (struct tpm_header *)buf->data;
+ head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
+ }
+ tpm_buf_append_u16(buf, max);
+
+ ret = tpm_buf_fill_hmac_session(chip, buf);
+ if (ret)
+ return ret;
+
+ ret = tpm_transmit_cmd(chip, buf, offsetof(struct tpm2_get_random_out, buffer),
+ "TPM2_GetRandom");
+
+ ret = tpm_buf_check_hmac_response(chip, buf, ret);
+ if (ret) {
+ if (ret > 0)
+ ret = -EIO;
+
+ goto out;
+ }
+
+ 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];
+ recd = min_t(u32, be16_to_cpu(resp->size), max);
+
+ if (tpm_buf_length(buf) <
+ TPM_HEADER_SIZE + offsetof(struct tpm2_get_random_out, buffer) + recd) {
+ ret = -EIO;
+ goto out;
+ }
+
+ memcpy(out, resp->buffer, recd);
+ return recd;
+
+out:
+ tpm2_end_auth_session(chip);
+ return ret;
+}
+
/**
- * tpm_get_random() - get random bytes from the TPM's RNG
- * @chip: a &struct tpm_chip instance, %NULL for the default chip
- * @out: destination buffer for the random bytes
- * @max: the max number of bytes to write to @out
+ * tpm_get_random() - Get random bytes from the TPM's RNG
+ * @chip: A &tpm_chip instance. Whenset to %NULL, the default chip is used.
+ * @out: Destination buffer for the acquired random bytes.
+ * @max: The maximum number of bytes to write to @out.
*
- * Return: number of random bytes read or a negative error value.
+ * Iterates pulling more bytes from TPM up until all of the @max bytes have been
+ * received.
+ *
+ * Returns the number of random bytes read on success.
+ * Returns -EINVAL when @out is NULL, or @max is not between zero and
+ * %TPM_MAX_RNG_DATA.
+ * Returns tpm_transmit_cmd() error codes when the TPM command results an
+ * error.
*/
int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
{
+ u32 num_bytes = max;
+ u8 *out_ptr = out;
+ int retries = 5;
+ int total = 0;
int rc;
- if (!out || max > TPM_MAX_RNG_DATA)
+ if (!out || !max || max > TPM_MAX_RNG_DATA)
return -EINVAL;
if (!chip)
@@ -508,11 +632,30 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
if (rc)
return rc;
- if (chip->flags & TPM_CHIP_FLAG_TPM2)
- rc = tpm2_get_random(chip, out, max);
- else
- rc = tpm1_get_random(chip, out, max);
+ if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+ rc = tpm2_start_auth_session(chip);
+ if (rc)
+ return rc;
+ }
+
+ do {
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ rc = tpm2_get_random(chip, out_ptr, num_bytes);
+ else
+ rc = tpm1_get_random(chip, out_ptr, num_bytes);
+
+ if (rc < 0)
+ goto err;
+
+ out_ptr += rc;
+ total += rc;
+ num_bytes -= rc;
+ } while (retries-- && total < max);
+
+ tpm_put_ops(chip);
+ return total ? total : -EIO;
+err:
tpm_put_ops(chip);
return rc;
}
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 5395927c62fc..c4bbd8f04605 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -250,7 +250,6 @@ int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
const char *desc, size_t min_cap_length);
-int tpm1_get_random(struct tpm_chip *chip, u8 *out, size_t max);
int tpm1_get_pcr_allocation(struct tpm_chip *chip);
unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
int tpm_pm_suspend(struct device *dev);
@@ -290,7 +289,6 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digest, u16 *digest_size_ptr);
int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digests);
-int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,
u32 *value, const char *desc);
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 11090053ef54..d8f16e66666b 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -502,68 +502,6 @@ ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
}
EXPORT_SYMBOL_GPL(tpm1_getcap);
-#define TPM_ORD_GET_RANDOM 70
-struct tpm1_get_random_out {
- __be32 rng_data_len;
- u8 rng_data[TPM_MAX_RNG_DATA];
-} __packed;
-
-/**
- * tpm1_get_random() - get random bytes from the TPM's RNG
- * @chip: a &struct tpm_chip instance
- * @dest: destination buffer for the random bytes
- * @max: the maximum number of bytes to write to @dest
- *
- * Return:
- * * number of bytes read
- * * -errno (positive TPM return codes are masked to -EIO)
- */
-int tpm1_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
-{
- struct tpm1_get_random_out *out;
- u32 num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA);
- u32 total = 0;
- int retries = 5;
- u32 recd;
- int rc;
-
- struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- tpm_buf_init(buf, TPM_BUFSIZE);
- do {
- tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_GET_RANDOM);
- tpm_buf_append_u32(buf, num_bytes);
-
- rc = tpm_transmit_cmd(chip, buf, sizeof(out->rng_data_len), "TPM_GetRandom");
- if (rc) {
- if (rc > 0)
- rc = -EIO;
- return rc;
- }
-
- out = (struct tpm1_get_random_out *)&buf->data[TPM_HEADER_SIZE];
-
- recd = be32_to_cpu(out->rng_data_len);
- if (recd > num_bytes)
- return -EFAULT;
-
- if (buf->length < TPM_HEADER_SIZE +
- sizeof(out->rng_data_len) + recd)
- return -EFAULT;
-
- memcpy(dest, out->rng_data, recd);
-
- dest += recd;
- total += recd;
- num_bytes -= recd;
- } while (retries-- && total < max);
-
- rc = total ? (int)total : -EIO;
- return rc;
-}
-
#define TPM_ORD_PCRREAD 21
int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
{
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index bc50d6b734cf..f066efb54a2c 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -233,101 +233,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
return rc;
}
-struct tpm2_get_random_out {
- __be16 size;
- u8 buffer[TPM_MAX_RNG_DATA];
-} __packed;
-
-/**
- * tpm2_get_random() - get random bytes from the TPM RNG
- *
- * @chip: a &tpm_chip instance
- * @dest: destination buffer
- * @max: the max number of random bytes to pull
- *
- * Return:
- * size of the buffer on success,
- * -errno otherwise (positive TPM return codes are masked to -EIO)
- */
-int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
-{
- struct tpm2_get_random_out *out;
- struct tpm_header *head;
- u32 recd;
- u32 num_bytes = max;
- int err;
- int total = 0;
- int retries = 5;
- u8 *dest_ptr = dest;
- off_t offset;
-
- if (!num_bytes || max > TPM_MAX_RNG_DATA)
- return -EINVAL;
-
- struct tpm_buf *buf __free(kfree) = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- err = tpm2_start_auth_session(chip);
- if (err)
- return err;
-
- tpm_buf_init(buf, TPM_BUFSIZE);
- do {
- tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_GET_RANDOM);
- if (tpm2_chip_auth(chip)) {
- tpm_buf_append_hmac_session(chip, buf,
- TPM2_SA_ENCRYPT |
- TPM2_SA_CONTINUE_SESSION,
- NULL, 0);
- } else {
- head = (struct tpm_header *)buf->data;
- head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
- }
- tpm_buf_append_u16(buf, num_bytes);
- 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),
- "TPM2_GetRandom");
- err = tpm_buf_check_hmac_response(chip, buf, err);
- if (err) {
- if (err > 0)
- err = -EIO;
- goto out;
- }
-
- 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;
-
- out = (struct tpm2_get_random_out *)&buf->data[offset];
- recd = min_t(u32, be16_to_cpu(out->size), num_bytes);
- if (tpm_buf_length(buf) <
- TPM_HEADER_SIZE +
- offsetof(struct tpm2_get_random_out, buffer) +
- recd) {
- err = -EFAULT;
- goto out;
- }
- memcpy(dest_ptr, out->buffer, recd);
-
- dest_ptr += recd;
- total += recd;
- num_bytes -= recd;
- } while (retries-- && total < max);
-
- return total ? total : -EIO;
-out:
- tpm2_end_auth_session(chip);
- return err;
-}
-
/**
* tpm2_flush_context() - execute a TPM2_FlushContext command
* @chip: TPM chip to use
--
2.39.5
^ permalink raw reply related
* [PATCH v4 7/8] tpm: Send only one at most TPM2_GetRandom command
From: Jarkko Sakkinen @ 2025-12-10 17:20 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, David S . Miller, Herbert Xu, Peter Huewe,
Jason Gunthorpe, David Howells, Paul Moore, James Morris,
Serge E. Hallyn, James Bottomley, Mimi Zohar, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210172027.109938-1-jarkko@kernel.org>
hwrng framework does not have a requirement that the all bytes requested
need to be provided. By enforcing such a requirement internally, TPM driver
can cause unpredictability in latency, as a single tpm_get_random() call
can result multiple TPM commands.
Especially, when TCG_TPM2_HMAC is enabled, extra roundtrips could have
significant effect to the system latency.
Add a wait-parameter to enforce the old behavior and set it to true only at
the call sites for TPM 1.2 keys. At the call sites of hwrng, set @wait to
false.
Cc: David S. Miller <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v4:
- Fixed grammar mistakes.
---
drivers/char/tpm/tpm-chip.c | 2 +-
drivers/char/tpm/tpm-interface.c | 11 +++++++++--
include/linux/tpm.h | 2 +-
security/keys/trusted-keys/trusted_tpm1.c | 8 ++++----
4 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 082b910ddf0d..8fca4373e2df 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -494,7 +494,7 @@ static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
{
struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng);
- return tpm_get_random(chip, data, max);
+ return tpm_get_random(chip, data, max, false);
}
static bool tpm_is_hwrng_enabled(struct tpm_chip *chip)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index ab52a1cb0a78..5cc2bbabd57a 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -604,9 +604,11 @@ static int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
* @chip: A &tpm_chip instance. Whenset to %NULL, the default chip is used.
* @out: Destination buffer for the acquired random bytes.
* @max: The maximum number of bytes to write to @out.
+ * @wait: Set to true when all of the @max bytes need to be acquired.
*
* Iterates pulling more bytes from TPM up until all of the @max bytes have been
- * received.
+ * received, when @wait it sets true. Otherwise, the queries for @max bytes from
+ * TPM exactly once, and returns the bytes that were received.
*
* Returns the number of random bytes read on success.
* Returns -EINVAL when @out is NULL, or @max is not between zero and
@@ -614,7 +616,7 @@ static int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
* Returns tpm_transmit_cmd() error codes when the TPM command results an
* error.
*/
-int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
+int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max, bool wait)
{
u32 num_bytes = max;
u8 *out_ptr = out;
@@ -647,6 +649,11 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
if (rc < 0)
goto err;
+ if (!wait) {
+ total = rc;
+ break;
+ }
+
out_ptr += rc;
total += rc;
num_bytes -= rc;
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index e68995df8796..177833d6b965 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -485,7 +485,7 @@ extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digest);
extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digests);
-extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
+int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max, bool wait);
extern struct tpm_chip *tpm_default_chip(void);
void tpm2_flush_context(struct tpm_chip *chip, u32 handle);
int tpm2_find_hash_alg(unsigned int crypto_id);
diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c
index 759c1ecb0435..f36f6a0b533f 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -361,7 +361,7 @@ static int osap(struct tpm_buf *tb, struct osapsess *s,
unsigned char ononce[TPM_NONCE_SIZE];
int ret;
- ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE);
+ ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE, true);
if (ret < 0)
return ret;
@@ -454,7 +454,7 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
- ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE);
+ ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE, true);
if (ret < 0)
goto out;
@@ -565,7 +565,7 @@ static int tpm_unseal(struct tpm_buf *tb,
}
ordinal = htonl(TPM_ORD_UNSEAL);
- ret = tpm_get_random(chip, nonceodd, TPM_NONCE_SIZE);
+ ret = tpm_get_random(chip, nonceodd, TPM_NONCE_SIZE, true);
if (ret < 0)
return ret;
@@ -938,7 +938,7 @@ static int trusted_tpm_unseal(struct trusted_key_payload *p, char *datablob)
static int trusted_tpm_get_random(unsigned char *key, size_t key_len)
{
- return tpm_get_random(chip, key, key_len);
+ return tpm_get_random(chip, key, key_len, true);
}
static int __init init_digests(void)
--
2.39.5
^ permalink raw reply related
* [PATCH v4 8/8] tpm: In tpm_get_random() replace 'retries' with a zero check
From: Jarkko Sakkinen @ 2025-12-10 17:20 UTC (permalink / raw)
To: linux-integrity
Cc: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, open list,
open list:KEYS/KEYRINGS, open list:SECURITY SUBSYSTEM
In-Reply-To: <20251210172027.109938-1-jarkko@kernel.org>
Check for zero byte read instead of having retries counter in order to make
wait flag properly enforcing. Progress is still guaranteed given the zero
check and iterations are capped up to TPM_MAX_RNG_DATA iterations at most
(as per theoretical limit).
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
drivers/char/tpm/tpm-interface.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5cc2bbabd57a..594ad095a90b 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -620,7 +620,6 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max, bool wait)
{
u32 num_bytes = max;
u8 *out_ptr = out;
- int retries = 5;
int total = 0;
int rc;
@@ -646,8 +645,12 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max, bool wait)
else
rc = tpm1_get_random(chip, out_ptr, num_bytes);
- if (rc < 0)
+ if (rc <= 0) {
+ if (!rc)
+ rc = -EIO;
+
goto err;
+ }
if (!wait) {
total = rc;
@@ -657,7 +660,7 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max, bool wait)
out_ptr += rc;
total += rc;
num_bytes -= rc;
- } while (retries-- && total < max);
+ } while (total < max);
tpm_put_ops(chip);
return total ? total : -EIO;
--
2.39.5
^ permalink raw reply related
* Re: [RFC][PATCH] ima: Add support for staging measurements for deletion
From: Gregory Lumen @ 2025-12-10 19:12 UTC (permalink / raw)
To: Roberto Sassu
Cc: corbet, zohar, dmitry.kasatkin, eric.snowberg, paul, jmorris,
serge, linux-doc, linux-kernel, linux-integrity,
linux-security-module, chenste, nramas, Roberto Sassu
In-Reply-To: <20251209101725.3680225-1-roberto.sassu@huaweicloud.com>
Roberto,
The proposed approach appears to be workable. However, if our primary goal
here is to enable UM to free kernel memory consumed by the IMA log with an
absolute minimum of kernel functionality/change, then I would argue that
the proposed Stage-then-delete approach still represents unnecessary
complexity when compared to a trim-to-N solution. Specifically:
- Any functional benefit offered through the introduction of a staged
measurement list could be equally achieved in UM with a trim-to-N solution
coupled with the proposed ima_measure_users counter for access locking.
- There exists a potential UM measurement-loss race condition introduced
by the staging functionality that would not exist with a trim-to-N
approach. (Occurs if a kexec call occurs after a UM agent has staged
measurements for deletion, but has not completed copying them to
userspace). This could be avoided by persisting staged measurements across
kexec calls at the cost of making the proposed change larger.
Thanks,
-Gregory Lumen
^ permalink raw reply
* Re: [PATCH 1/1] IMA event log trimming
From: Mimi Zohar @ 2025-12-10 19:16 UTC (permalink / raw)
To: Roberto Sassu, James Bottomley, steven chen, linux-integrity
Cc: roberto.sassu, dmitry.kasatkin, eric.snowberg, paul, jmorris,
serge, linux-security-module, anirudhve, gregorylumen, nramas,
sushring
In-Reply-To: <736e21826c6a283d74d592393c392abbff56a409.camel@huaweicloud.com>
On Tue, 2025-12-09 at 10:36 +0100, Roberto Sassu wrote:
> On Tue, 2025-12-09 at 07:17 +0900, James Bottomley wrote:
> > On Mon, 2025-12-08 at 10:40 +0100, Roberto Sassu wrote:
> > > I have the impression that none the functionality you cited has to be
> > > implemented in the kernel, because the only component one can trust
> > > to verify the integrity of the IMA measurements list is the TPM.
> > > Whether either the kernel or user space retain the measurements is
> > > irrelevant.
> >
> > That's correct, I'm not advocating moving quoting into the kernel. Co-
> > ordinating the trim with where the quote gets you to is phenomenally
> > useful. While you could theoretically store any mismatch in userspace,
> > having two locations for the log makes it more error prone.
> >
> > > I believe that the only role of the kernel is to get rid of the
> > > measurements entries as fast as possible (the kernel would act more
> > > like a buffer).
> >
> > I wouldn't say that, I'd say to get rid of measurements that the user
> > has indicated are of no further use\
I really hope I'm wrong, but I don't like the sound of "No further use". The
complete IMA measurement needs to be saved somewhere to support multiple
verifiers.
>
> Different users could have different and conflicting requirements, and
> we would spend time trying to conciliate those. We can avoid that by
> doing it the same for everyone, and the additional cost of handling it
> I believe it is fair.
>
> I could accept staging N entries since I already agreed with Gregory
> and Steven, and since it requires only an extra iteration in the linked
> list. The other desired functionality should be implemented in user
> space.
>
> > > This was actually the intent of my original proposal in
> > > https://github.com/linux-integrity/linux/issues/1 . The idea of
> > > staging (was snapshotting, but Mimi thinks the term is not accurate)
> > > is simply to detach the entire IMA measurement list as fast as
> > > possible. Further read and delete after staging is done without
> > > interfering with new measurements (sure, the detaching of the hash
> > > table is not yet as efficient as I hoped).
> >
> > From the application point of view, offloading the log and random
> > points is a bit more work because now the log collector has to be
> > modified to look in multiple locations and we'd also need an agreement
> > of where those locations are and how the log is sequenced in a naming
> > scheme so it's the same for every distribution. If the application is
> > in charge of trimming the log at a particular point, collection remains
> > the same (it can simply be the existing in-kernel location), so we
> > don't need a cross distro agreement, and the trim can simply be added
> > as an extra function.
>
> It could be a single location, the user space program would be
> responsible to present the IMA measurement list as if it was never
> trimmed.
Even if it is a single, new location or user space program/daemon, it needs to
be documented. The user space program/daemon would be responsible for returning
the IMA measurement list.
Keylime, for example, supports incremental verification[1], meaning initially
the verification would be from the beginning of the IMA measurement list, but
subsequently the verifier could do an incremental verification. For incremental
verification, state information (e.g. number of records verified, pcr value)
needs to be preserved by the verifier, not the kernel.
[1] Keylime commit 7870f45f909f ("ima: Remember the number of lines successfully
processed and last IMA PCR value(s)")
--
thanks,
Mimi
^ permalink raw reply
* [PATCH v2 0/1] Trim N entries of IMA event logs
From: steven chen @ 2025-12-10 23:53 UTC (permalink / raw)
To: linux-integrity
Cc: zohar, roberto.sassu, dmitry.kasatkin, eric.snowberg, corbet,
serge, paul, jmorris, linux-security-module, anirudhve, chenste,
gregorylumen, nramas, sushring, linux-doc
The Integrity Measurement Architecture (IMA) maintains a measurement list
—a record of system events used for integrity verification. The IMA event
logs are the entries within this measurement list, each representing a
specific event or measurement that contributes to the system's integrity
assessment.
This update introduces the ability to trim, or remove, N entries from the
current measurement list. Trimming involves deleting N entries from the
list and clearing the corresponding entries from the hash table. This
action atomically truncates the measurement list, ensuring that no new
measurements can be added until the operation is complete. Importantly,
only one writer can initiate this trimming process at a time, maintaining
consistency and preventing race conditions.
A userspace interface, ima_trim_log, has been provided for this purpose.
By writing a number N to this interface, userspace can request the kernel
to trim N entries from the IMA event logs. When this interface is read,
it returns the number of entries trimmed during the last operation. This
value is not preserved across kexec soft reboots, as it is not considered
important information.
To maintain a complete record, userspace is responsible for concatenating
and storing the logs before initiating trimming. Userspace can then send
the collected data to remote verifiers for validation. After receiving
confirmation from the remote verifiers, userspace may instruct the kernel
to proceed with trimming the IMA event logs accordingly.
The primary benefit of this solution is the ability to free valuable
kernel memory by delegating the task of reconstructing the full
measurement list from log chunks to userspace. Trust is not required in
userspace for the integrity of the measurement list, as its integrity is
cryptographically protected by the Trusted Platform Module (TPM).
Multiple readers are allowed to access the ima_trim_log interface
concurrently, while only one writer can trigger log trimming at any time.
During trimming, readers do not see the list and cannot access it while
deletion is in progress, ensuring atomicity.
Introduce the new kernel option ima_flush_htable to decide whether or not
the digests of measurement entries are flushed from the hash table. (from
reference [2])
The ima_measure_users counter (protected by the ima_measure_lock mutex) has
been introduced to protect access to the measurement list part. The open
method of all the measurement interfaces has been extended to allow only
one writer at a time or, in alternative, multiple readers. The write
permission is used to delete the measurements, the read permission
to read them. Write requires also the CAP_SYS_ADMIN capability. (from
reference [2])
New IMA log trim event is added when trimming finish.
The time required for trimming is minimal, and IMA event logs are briefly
on hold during this process, preventing read or add operations. This short
interruption has no impact on the overall functionality of IMA.
V1 of this series is available here[1] for reference.
References:
-----------
[1] [PATCH 0/1] Trim N entries of IMA event logs
https://lore.kernel.org/linux-integrity/20251202232857.8211-1-chenste@linux.microsoft.com/T/#t
[2] [RFC][PATCH] ima: Add support for staging measurements for deletion
https://lore.kernel.org/linux-integrity/207fd6d7-53c-57bb-36d8-13a0902052d1@linux.microsoft.com/T/#t
Change Log v2:
- Incorporated feedback from the Roberto on v1 series.
- Adapted code from Roberto's RFC [Reference 2]
- Add IMA log trim event log to record trim event
- Updated patch descriptions as necessary.
steven chen (1):
IMA event log trimming
.../admin-guide/kernel-parameters.txt | 4 +
security/integrity/ima/ima.h | 2 +
security/integrity/ima/ima_fs.c | 175 +++++++++++++++++-
security/integrity/ima/ima_queue.c | 64 +++++++
4 files changed, 241 insertions(+), 4 deletions(-)
--
2.43.0
^ permalink raw reply
* [PATCH V2 1/1] IMA event log trimming
From: steven chen @ 2025-12-10 23:53 UTC (permalink / raw)
To: linux-integrity
Cc: zohar, roberto.sassu, dmitry.kasatkin, eric.snowberg, corbet,
serge, paul, jmorris, linux-security-module, anirudhve, chenste,
gregorylumen, nramas, sushring, linux-doc
In-Reply-To: <20251210235314.3341-1-chenste@linux.microsoft.com>
This patch is for trimming N entries of the IMA event logs. It will also
cleaning the hash table if ima_flush_htable is set.
It provides a userspace interface ima_trim_log that can be used to input
number N to let kernel to trim N entries of IMA event logs. When read
this interface, it returns number of entries trimmed last time.
Signed-off-by: steven chen <chenste@linux.microsoft.com>
---
.../admin-guide/kernel-parameters.txt | 4 +
security/integrity/ima/ima.h | 2 +
security/integrity/ima/ima_fs.c | 175 +++++++++++++++++-
security/integrity/ima/ima_queue.c | 64 +++++++
4 files changed, 241 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index e92c0056e4e0..cd1a1d0bf0e2 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2197,6 +2197,10 @@
Use the canonical format for the binary runtime
measurements, instead of host native format.
+ ima_flush_htable [IMA]
+ Flush the measurement list hash table when trim all
+ or a part of it for deletion.
+
ima_hash= [IMA]
Format: { md5 | sha1 | rmd160 | sha256 | sha384
| sha512 | ... }
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index e3d71d8d56e3..ab0e30ee25ea 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -246,8 +246,10 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key,
#ifdef CONFIG_IMA_KEXEC
void ima_measure_kexec_event(const char *event_name);
+long ima_purge_event_log(long number_logs);
#else
static inline void ima_measure_kexec_event(const char *event_name) {}
+static inline long ima_purge_event_log(long number_logs) { return 0; }
#endif
/*
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 87045b09f120..410f7d03c43f 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -21,6 +21,9 @@
#include <linux/rcupdate.h>
#include <linux/parser.h>
#include <linux/vmalloc.h>
+#include <linux/ktime.h>
+#include <linux/timekeeping.h>
+#include <linux/ima.h>
#include "ima.h"
@@ -38,6 +41,14 @@ __setup("ima_canonical_fmt", default_canonical_fmt_setup);
static int valid_policy = 1;
+#define IMA_LOG_TRIM_REQ_LENGTH 11
+#define IMA_LOG_TRIM_EVENT_LEN 256
+
+static long trimcount;
+/* mutex protects atomicity of trimming measurement list requests */
+static DEFINE_MUTEX(ima_measure_lock);
+static long ima_measure_users;
+
static ssize_t ima_show_htable_value(char __user *buf, size_t count,
loff_t *ppos, atomic_long_t *val)
{
@@ -202,16 +213,65 @@ static const struct seq_operations ima_measurments_seqops = {
.show = ima_measurements_show
};
+static int _ima_measurements_open(struct inode *inode, struct file *file,
+ const struct seq_operations *seq_ops)
+{
+ bool write = !!(file->f_mode & FMODE_WRITE);
+ int ret;
+
+ if (write && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ mutex_lock(&ima_measure_lock);
+ if ((write && ima_measure_users != 0) ||
+ (!write && ima_measure_users < 0)) {
+ mutex_unlock(&ima_measure_lock);
+ return -EBUSY;
+ }
+
+ ret = seq_open(file, seq_ops);
+ if (ret < 0) {
+ mutex_unlock(&ima_measure_lock);
+ return ret;
+ }
+
+ if (write)
+ ima_measure_users--;
+ else
+ ima_measure_users++;
+
+ mutex_unlock(&ima_measure_lock);
+ return ret;
+}
+
static int ima_measurements_open(struct inode *inode, struct file *file)
{
- return seq_open(file, &ima_measurments_seqops);
+ return _ima_measurements_open(inode, file, &ima_measurments_seqops);
+}
+
+static int ima_measurements_release(struct inode *inode, struct file *file)
+{
+ bool write = !!(file->f_mode & FMODE_WRITE);
+ int ret;
+
+ mutex_lock(&ima_measure_lock);
+ ret = seq_release(inode, file);
+ if (!ret) {
+ if (write)
+ ima_measure_users++;
+ else
+ ima_measure_users--;
+ }
+
+ mutex_unlock(&ima_measure_lock);
+ return ret;
}
static const struct file_operations ima_measurements_ops = {
.open = ima_measurements_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = seq_release,
+ .release = ima_measurements_release,
};
void ima_print_digest(struct seq_file *m, u8 *digest, u32 size)
@@ -279,14 +339,111 @@ static const struct seq_operations ima_ascii_measurements_seqops = {
static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
{
- return seq_open(file, &ima_ascii_measurements_seqops);
+ return _ima_measurements_open(inode, file, &ima_ascii_measurements_seqops);
}
static const struct file_operations ima_ascii_measurements_ops = {
.open = ima_ascii_measurements_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = seq_release,
+ .release = ima_measurements_release,
+};
+
+static void ima_measure_trim_event(const long number_logs)
+{
+ char ima_log_trim_event[IMA_LOG_TRIM_EVENT_LEN];
+ struct timespec64 ts;
+ u64 time_ns;
+ int n;
+
+ ktime_get_real_ts64(&ts);
+ time_ns = (u64)ts.tv_sec * 1000000000ULL + ts.tv_nsec;
+ n = scnprintf(ima_log_trim_event, IMA_LOG_TRIM_EVENT_LEN,
+ "time=%llu; log trim this time=%lu;",
+ time_ns, number_logs);
+
+ ima_measure_critical_data("ima_log_trim", "trim ima event logs", ima_log_trim_event, n, false, NULL, 0);
+}
+
+static int ima_log_trim_open(struct inode *inode, struct file *file)
+{
+ bool write = !!(file->f_mode & FMODE_WRITE);
+
+ if (!write && capable(CAP_SYS_ADMIN))
+ return 0;
+ else if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ return _ima_measurements_open(inode, file, &ima_measurments_seqops);
+}
+
+static ssize_t ima_log_trim_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
+{
+ char tmpbuf[IMA_LOG_TRIM_REQ_LENGTH]; /* greater than largest 'long' string value */
+ ssize_t len;
+
+ len = scnprintf(tmpbuf, sizeof(tmpbuf), "%li\n", trimcount);
+ return simple_read_from_buffer(buf, size, ppos, tmpbuf, len);
+}
+
+static ssize_t ima_log_trim_write(struct file *file,
+ const char __user *buf, size_t datalen, loff_t *ppos)
+{
+ unsigned char req[IMA_LOG_TRIM_REQ_LENGTH];
+ long count, n;
+ int ret;
+
+ if (*ppos > 0 || datalen > IMA_LOG_TRIM_REQ_LENGTH || datalen < 2) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ n = (int)datalen;
+
+ ret = copy_from_user(req, buf, datalen);
+ if (ret < 0)
+ goto out;
+
+ count = 0;
+ for (int i = 0; i < n; ++i) {
+ if (req[i] < '0' || req[i] > '9') {
+ ret = -EINVAL;
+ goto out;
+ }
+ count = count * 10 + req[i] - '0';
+ }
+ ret = ima_purge_event_log(count);
+
+ if (ret < 0)
+ goto out;
+
+ trimcount = ret;
+
+ if (trimcount > 0)
+ ima_measure_trim_event(trimcount);
+
+ ret = datalen;
+out:
+ return ret;
+}
+
+static int ima_log_trim_release(struct inode *inode, struct file *file)
+{
+ bool write = !!(file->f_mode & FMODE_WRITE);
+ if (!write && capable(CAP_SYS_ADMIN))
+ return 0;
+ else if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ return ima_measurements_release(inode, file);
+}
+
+static const struct file_operations ima_log_trim_ops = {
+ .open = ima_log_trim_open,
+ .read = ima_log_trim_read,
+ .write = ima_log_trim_write,
+ .llseek = generic_file_llseek,
+ .release = ima_log_trim_release
};
static ssize_t ima_read_policy(char *path)
@@ -528,6 +685,16 @@ int __init ima_fs_init(void)
goto out;
}
+ dentry = securityfs_create_file("ima_trim_log",
+ S_IRUSR | S_IRGRP | S_IWUSR | S_IWGRP,
+ ima_dir, NULL, &ima_log_trim_ops);
+ if (IS_ERR(dentry)) {
+ ret = PTR_ERR(dentry);
+ goto out;
+ }
+
+ trimcount = 0;
+
dentry = securityfs_create_file("runtime_measurements_count",
S_IRUSR | S_IRGRP, ima_dir, NULL,
&ima_measurements_count_ops);
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index 590637e81ad1..77ab52469727 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -22,6 +22,14 @@
#define AUDIT_CAUSE_LEN_MAX 32
+bool ima_flush_htable;
+static int __init ima_flush_htable_setup(char *str)
+{
+ ima_flush_htable = true;
+ return 1;
+}
+__setup("ima_flush_htable", ima_flush_htable_setup);
+
/* pre-allocated array of tpm_digest structures to extend a PCR */
static struct tpm_digest *digests;
@@ -220,6 +228,62 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
return result;
}
+/* Delete the IMA event logs */
+long ima_purge_event_log(long number_logs)
+{
+ struct ima_queue_entry *qe, *qe_tmp;
+ LIST_HEAD(ima_measurements_staged);
+ unsigned int i;
+ long cur = number_logs;
+
+ if (number_logs <= 0)
+ return number_logs;
+
+ mutex_lock(&ima_extend_list_mutex);
+
+
+ list_for_each_entry(qe, &ima_measurements, later) {
+ if (--number_logs == 0)
+ break;
+ }
+
+ if (number_logs > 0) {
+ mutex_unlock(&ima_extend_list_mutex);
+ return -ENOENT;
+ }
+
+ __list_cut_position(&ima_measurements_staged, &ima_measurements,
+ &qe->later);
+ atomic_long_sub(cur, &ima_htable.len);
+
+ if (!IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE) && ima_flush_htable) {
+ list_for_each_entry(qe, &ima_measurements_staged, later)
+ /* It can race with ima_lookup_digest_entry(). */
+ hlist_del_rcu(&qe->hnext);
+ }
+
+ mutex_unlock(&ima_extend_list_mutex);
+
+
+ list_for_each_entry_safe(qe, qe_tmp, &ima_measurements_staged, later) {
+ for (i = 0; i < qe->entry->template_desc->num_fields; i++) {
+ kfree(qe->entry->template_data[i].data);
+ qe->entry->template_data[i].data = NULL;
+ qe->entry->template_data[i].len = 0;
+ }
+
+ list_del(&qe->later);
+
+ if (ima_flush_htable) {
+ kfree(qe->entry->digests);
+ kfree(qe->entry);
+ kfree(qe);
+ }
+ }
+
+ return cur;
+}
+
int ima_restore_measurement_entry(struct ima_template_entry *entry)
{
int result = 0;
--
2.43.0
^ permalink raw reply related
* Re: [RFC][PATCH] ima: Add support for staging measurements for deletion
From: steven chen @ 2025-12-11 0:03 UTC (permalink / raw)
To: Roberto Sassu, corbet, zohar, dmitry.kasatkin, eric.snowberg,
paul, jmorris, serge
Cc: linux-doc, linux-kernel, linux-integrity, linux-security-module,
gregorylumen, nramas, Roberto Sassu, steven chen
In-Reply-To: <20251209101725.3680225-1-roberto.sassu@huaweicloud.com>
On 12/9/2025 2:17 AM, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu@huawei.com>
>
> Introduce the ability of staging the entire of the IMA measurement list, or
> a portion, for deletion. Staging means moving the current content of the
> measurement list to a separate location, and allowing users to read and
> delete it. This causes the measurement list to be atomically truncated
> before new measurements can be added. Staging can be done only once at a
> time.
>
> User space is responsible to concatenate the staged IMA measurements list
> portions following the temporal order in which the operations were done,
> together with the current measurement list. Then, it can send the collected
> data to the remote verifiers.
>
> The benefit of this solution is the ability to free precious kernel memory,
> in exchange of delegating user space to reconstruct the full measurement
> list from the chunks. No trust needs to be given to user space, since the
> integrity of the measurement list is protected by the TPM.
>
> By default, staging the measurements list for deletion does not alter the
> hash table. When staging is done, IMA is still able to detect collisions on
> the staged and later deleted measurement entries, by keeping the entry
> digests (only template data are freed).
>
> However, since during the measurements list serialization only the SHA1
> digest is passed, and since there are no template data to recalculate the
> other digests from, the hash table is currently not populated with digests
> from staged/deleted entries after kexec().
>
> Introduce the new kernel option ima_flush_htable to decide whether or not
> the digests of staged measurement entries are flushed from the hash table.
>
> Then, introduce ascii_runtime_measurements_staged_<algo> and
> binary_runtime_measurement_staged_<algo> interfaces to stage/delete the
> measurements. Use 'echo A > <IMA interface>' and 'echo D > <IMA interface>'
> to respectively stage and delete the entire measurements list. Use
> 'echo N > <IMA interface>', with N between 1 and ULONG_MAX, to stage the
> selected portion of the measurements list.
>
> The ima_measure_users counter (protected by the ima_measure_lock mutex) has
> been introduced to protect access to the measurement list and the staged
> part. The open method of all the measurement interfaces has been extended
> to allow only one writer at a time or, in alternative, multiple readers.
> The write permission is used to stage/delete the measurements, the read
> permission to read them. Write requires also the CAP_SYS_ADMIN capability.
Hi Roberto,
I released version 2 of trim N entries patch as bellow:
[PATCH v2 0/1] Trim N entries of IMA event logs
<https://lore.kernel.org/linux-integrity/20251210235314.3341-1-chenste@linux.microsoft.com/T/#t>
I adapted some of your idea and I think trim N has following advantages:
1: less measurement list hold time than your current implementation
2. operation much simple for user space
3. less kernel code change
4. no potential issue as Gregory mentioned.
Thanks,
Steven
> Finally, introduce the _notrim version of the run-time measurements count
> and the binary measurements list size, to display them in the kexec-related
> critical data records.
>
> Note: This code derives from the Alt-IMA Huawei project, and is being
> released under the dual license model (GPL-2.0 OR MIT).
>
> Link: https://github.com/linux-integrity/linux/issues/1
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
> .../admin-guide/kernel-parameters.txt | 4 +
> security/integrity/ima/ima.h | 10 +-
> security/integrity/ima/ima_fs.c | 222 +++++++++++++++++-
> security/integrity/ima/ima_kexec.c | 13 +-
> security/integrity/ima/ima_queue.c | 111 ++++++++-
> 5 files changed, 340 insertions(+), 20 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 6c42061ca20e..355d8930e3ac 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2215,6 +2215,10 @@
> Use the canonical format for the binary runtime
> measurements, instead of host native format.
>
> + ima_flush_htable [IMA]
> + Flush the measurement list hash table when staging all
> + or a part of it for deletion.
> +
> ima_hash= [IMA]
> Format: { md5 | sha1 | rmd160 | sha256 | sha384
> | sha512 | ... }
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index e3d71d8d56e3..d7aa4a0f79b1 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -117,6 +117,8 @@ struct ima_queue_entry {
> struct ima_template_entry *entry;
> };
> extern struct list_head ima_measurements; /* list of all measurements */
> +extern struct list_head ima_measurements_staged; /* list of staged meas. */
> +extern bool ima_measurements_staged_exist; /* If there are staged meas. */
>
> /* Some details preceding the binary serialized measurement list */
> struct ima_kexec_hdr {
> @@ -281,10 +283,12 @@ struct ima_template_desc *ima_template_desc_current(void);
> struct ima_template_desc *ima_template_desc_buf(void);
> struct ima_template_desc *lookup_template_desc(const char *name);
> bool ima_template_has_modsig(const struct ima_template_desc *ima_template);
> +int ima_queue_stage(unsigned long req_value);
> +int ima_queue_delete_staged(void);
> int ima_restore_measurement_entry(struct ima_template_entry *entry);
> int ima_restore_measurement_list(loff_t bufsize, void *buf);
> int ima_measurements_show(struct seq_file *m, void *v);
> -unsigned long ima_get_binary_runtime_size(void);
> +unsigned long ima_get_binary_runtime_size(bool notrim);
> int ima_init_template(void);
> void ima_init_template_list(void);
> int __init ima_init_digests(void);
> @@ -298,11 +302,13 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
> extern spinlock_t ima_queue_lock;
>
> struct ima_h_table {
> - atomic_long_t len; /* number of stored measurements in the list */
> + atomic_long_t len; /* current num of stored meas. in the list */
> + atomic_long_t len_notrim; /* total num of stored meas. in the list */
> atomic_long_t violations;
> struct hlist_head queue[IMA_MEASURE_HTABLE_SIZE];
> };
> extern struct ima_h_table ima_htable;
> +extern struct mutex ima_extend_list_mutex;
>
> static inline unsigned int ima_hash_key(u8 *digest)
> {
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index 87045b09f120..321c98ae0e55 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -24,7 +24,12 @@
>
> #include "ima.h"
>
> +/* Requests: ('A', [1, ULONG_MAX])\n (stage all/N) or D\n (delete staged) */
> +#define STAGED_REQ_LENGTH 21
> +
> static DEFINE_MUTEX(ima_write_mutex);
> +static DEFINE_MUTEX(ima_measure_lock);
> +static long ima_measure_users;
>
> bool ima_canonical_fmt;
> static int __init default_canonical_fmt_setup(char *str)
> @@ -74,14 +79,15 @@ static const struct file_operations ima_measurements_count_ops = {
> };
>
> /* returns pointer to hlist_node */
> -static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
> +static void *_ima_measurements_start(struct seq_file *m, loff_t *pos,
> + struct list_head *head)
> {
> loff_t l = *pos;
> struct ima_queue_entry *qe;
>
> /* we need a lock since pos could point beyond last element */
> rcu_read_lock();
> - list_for_each_entry_rcu(qe, &ima_measurements, later) {
> + list_for_each_entry_rcu(qe, head, later) {
> if (!l--) {
> rcu_read_unlock();
> return qe;
> @@ -91,7 +97,18 @@ static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
> return NULL;
> }
>
> -static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
> +static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
> +{
> + return _ima_measurements_start(m, pos, &ima_measurements);
> +}
> +
> +static void *ima_measurements_staged_start(struct seq_file *m, loff_t *pos)
> +{
> + return _ima_measurements_start(m, pos, &ima_measurements_staged);
> +}
> +
> +static void *_ima_measurements_next(struct seq_file *m, void *v, loff_t *pos,
> + struct list_head *head)
> {
> struct ima_queue_entry *qe = v;
>
> @@ -103,7 +120,18 @@ static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
> rcu_read_unlock();
> (*pos)++;
>
> - return (&qe->later == &ima_measurements) ? NULL : qe;
> + return (&qe->later == head) ? NULL : qe;
> +}
> +
> +static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
> +{
> + return _ima_measurements_next(m, v, pos, &ima_measurements);
> +}
> +
> +static void *ima_measurements_staged_next(struct seq_file *m, void *v,
> + loff_t *pos)
> +{
> + return _ima_measurements_next(m, v, pos, &ima_measurements_staged);
> }
>
> static void ima_measurements_stop(struct seq_file *m, void *v)
> @@ -202,16 +230,138 @@ static const struct seq_operations ima_measurments_seqops = {
> .show = ima_measurements_show
> };
>
> +static int _ima_measurements_open(struct inode *inode, struct file *file,
> + const struct seq_operations *seq_ops)
> +{
> + bool write = !!(file->f_mode & FMODE_WRITE);
> + int ret;
> +
> + if (write && !capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + mutex_lock(&ima_measure_lock);
> + if ((write && ima_measure_users != 0) ||
> + (!write && ima_measure_users < 0)) {
> + mutex_unlock(&ima_measure_lock);
> + return -EBUSY;
> + }
> +
> + ret = seq_open(file, seq_ops);
> + if (ret < 0) {
> + mutex_unlock(&ima_measure_lock);
> + return ret;
> + }
> +
> + if (write)
> + ima_measure_users--;
> + else
> + ima_measure_users++;
> +
> + mutex_unlock(&ima_measure_lock);
> + return ret;
> +}
> +
> static int ima_measurements_open(struct inode *inode, struct file *file)
> {
> - return seq_open(file, &ima_measurments_seqops);
> + return _ima_measurements_open(inode, file, &ima_measurments_seqops);
> +}
> +
> +static int ima_measurements_release(struct inode *inode, struct file *file)
> +{
> + bool write = !!(file->f_mode & FMODE_WRITE);
> + int ret;
> +
> + mutex_lock(&ima_measure_lock);
> + ret = seq_release(inode, file);
> + if (!ret) {
> + if (write)
> + ima_measure_users++;
> + else
> + ima_measure_users--;
> + }
> +
> + mutex_unlock(&ima_measure_lock);
> + return ret;
> }
>
> static const struct file_operations ima_measurements_ops = {
> .open = ima_measurements_open,
> .read = seq_read,
> .llseek = seq_lseek,
> - .release = seq_release,
> + .release = ima_measurements_release,
> +};
> +
> +static const struct seq_operations ima_measurments_staged_seqops = {
> + .start = ima_measurements_staged_start,
> + .next = ima_measurements_staged_next,
> + .stop = ima_measurements_stop,
> + .show = ima_measurements_show
> +};
> +
> +static int ima_measurements_staged_open(struct inode *inode, struct file *file)
> +{
> + return _ima_measurements_open(inode, file,
> + &ima_measurments_staged_seqops);
> +}
> +
> +static ssize_t ima_measurements_staged_read(struct file *file, char __user *buf,
> + size_t size, loff_t *ppos)
> +{
> + if (!ima_measurements_staged_exist)
> + return -ENOENT;
> +
> + return seq_read(file, buf, size, ppos);
> +}
> +
> +static ssize_t ima_measurements_staged_write(struct file *file,
> + const char __user *buf,
> + size_t datalen, loff_t *ppos)
> +{
> + char req[STAGED_REQ_LENGTH], *req_ptr = req;
> + unsigned long req_value;
> + int ret;
> +
> + if (*ppos > 0 || datalen < 2 || datalen > STAGED_REQ_LENGTH)
> + return -EINVAL;
> +
> + ret = copy_from_user(req, buf, datalen);
> + if (ret < 0)
> + return ret;
> +
> + if (strsep(&req_ptr, "\n") == NULL)
> + return -EINVAL;
> +
> + switch (req[0]) {
> + case 'A':
> + if (datalen != 2 || req[1] != '\0')
> + return -EINVAL;
> +
> + ret = ima_queue_stage(ULONG_MAX);
> + break;
> + case 'D':
> + if (datalen != 2 || req[1] != '\0')
> + return -EINVAL;
> +
> + ret = ima_queue_delete_staged();
> + break;
> + default:
> + ret = kstrtoul(req, 0, &req_value);
> + if (!ret)
> + ret = ima_queue_stage(req_value);
> + }
> +
> + if (ret < 0)
> + return ret;
> +
> + return datalen;
> +}
> +
> +static const struct file_operations ima_measurements_staged_ops = {
> + .open = ima_measurements_staged_open,
> + .read = ima_measurements_staged_read,
> + .write = ima_measurements_staged_write,
> + .llseek = seq_lseek,
> + .release = ima_measurements_release,
> };
>
> void ima_print_digest(struct seq_file *m, u8 *digest, u32 size)
> @@ -279,14 +429,37 @@ static const struct seq_operations ima_ascii_measurements_seqops = {
>
> static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
> {
> - return seq_open(file, &ima_ascii_measurements_seqops);
> + return _ima_measurements_open(inode, file,
> + &ima_ascii_measurements_seqops);
> }
>
> static const struct file_operations ima_ascii_measurements_ops = {
> .open = ima_ascii_measurements_open,
> .read = seq_read,
> .llseek = seq_lseek,
> - .release = seq_release,
> + .release = ima_measurements_release,
> +};
> +
> +static const struct seq_operations ima_ascii_measurements_staged_seqops = {
> + .start = ima_measurements_staged_start,
> + .next = ima_measurements_staged_next,
> + .stop = ima_measurements_stop,
> + .show = ima_ascii_measurements_show
> +};
> +
> +static int ima_ascii_measurements_staged_open(struct inode *inode,
> + struct file *file)
> +{
> + return _ima_measurements_open(inode, file,
> + &ima_ascii_measurements_staged_seqops);
> +}
> +
> +static const struct file_operations ima_ascii_measurements_staged_ops = {
> + .open = ima_ascii_measurements_staged_open,
> + .read = ima_measurements_staged_read,
> + .write = ima_measurements_staged_write,
> + .llseek = seq_lseek,
> + .release = ima_measurements_release,
> };
>
> static ssize_t ima_read_policy(char *path)
> @@ -419,6 +592,25 @@ static int __init create_securityfs_measurement_lists(void)
> &ima_measurements_ops);
> if (IS_ERR(dentry))
> return PTR_ERR(dentry);
> +
> + sprintf(file_name, "ascii_runtime_measurements_staged_%s",
> + hash_algo_name[algo]);
> + dentry = securityfs_create_file(file_name,
> + S_IRUSR | S_IRGRP | S_IWUSR | S_IWGRP,
> + ima_dir, (void *)(uintptr_t)i,
> + &ima_ascii_measurements_staged_ops);
> + if (IS_ERR(dentry))
> + return PTR_ERR(dentry);
> +
> + sprintf(file_name, "binary_runtime_measurements_staged_%s",
> + hash_algo_name[algo]);
> + dentry = securityfs_create_file(file_name,
> + S_IRUSR | S_IRGRP |
> + S_IWUSR | S_IWGRP,
> + ima_dir, (void *)(uintptr_t)i,
> + &ima_measurements_staged_ops);
> + if (IS_ERR(dentry))
> + return PTR_ERR(dentry);
> }
>
> return 0;
> @@ -528,6 +720,20 @@ int __init ima_fs_init(void)
> goto out;
> }
>
> + dentry = securityfs_create_symlink("binary_runtime_measurements_staged",
> + ima_dir, "binary_runtime_measurements_staged_sha1", NULL);
> + if (IS_ERR(dentry)) {
> + ret = PTR_ERR(dentry);
> + goto out;
> + }
> +
> + dentry = securityfs_create_symlink("ascii_runtime_measurements_staged",
> + ima_dir, "ascii_runtime_measurements_staged_sha1", NULL);
> + if (IS_ERR(dentry)) {
> + ret = PTR_ERR(dentry);
> + goto out;
> + }
> +
> dentry = securityfs_create_file("runtime_measurements_count",
> S_IRUSR | S_IRGRP, ima_dir, NULL,
> &ima_measurements_count_ops);
> diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
> index 7362f68f2d8b..23a20300da7b 100644
> --- a/security/integrity/ima/ima_kexec.c
> +++ b/security/integrity/ima/ima_kexec.c
> @@ -40,8 +40,8 @@ void ima_measure_kexec_event(const char *event_name)
> long len;
> int n;
>
> - buf_size = ima_get_binary_runtime_size();
> - len = atomic_long_read(&ima_htable.len);
> + buf_size = ima_get_binary_runtime_size(true);
> + len = atomic_long_read(&ima_htable.len_notrim);
>
> n = scnprintf(ima_kexec_event, IMA_KEXEC_EVENT_LEN,
> "kexec_segment_size=%lu;ima_binary_runtime_size=%lu;"
> @@ -93,8 +93,10 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
>
> memset(&khdr, 0, sizeof(khdr));
> khdr.version = 1;
> - /* This is an append-only list, no need to hold the RCU read lock */
> - list_for_each_entry_rcu(qe, &ima_measurements, later, true) {
> +
> + /* It can race with ima_queue_stage(). */
> + mutex_lock(&ima_extend_list_mutex);
> + list_for_each_entry(qe, &ima_measurements, later) {
> if (ima_kexec_file.count < ima_kexec_file.size) {
> khdr.count++;
> ima_measurements_show(&ima_kexec_file, qe);
> @@ -103,6 +105,7 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
> break;
> }
> }
> + mutex_unlock(&ima_extend_list_mutex);
>
> /*
> * fill in reserved space with some buffer details
> @@ -157,7 +160,7 @@ void ima_add_kexec_buffer(struct kimage *image)
> else
> extra_memory = CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB * 1024;
>
> - binary_runtime_size = ima_get_binary_runtime_size() + extra_memory;
> + binary_runtime_size = ima_get_binary_runtime_size(false) + extra_memory;
>
> if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE)
> kexec_segment_size = ULONG_MAX;
> diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
> index 590637e81ad1..868f216ac343 100644
> --- a/security/integrity/ima/ima_queue.c
> +++ b/security/integrity/ima/ima_queue.c
> @@ -22,19 +22,32 @@
>
> #define AUDIT_CAUSE_LEN_MAX 32
>
> +bool ima_flush_htable;
> +static int __init ima_flush_htable_setup(char *str)
> +{
> + ima_flush_htable = true;
> + return 1;
> +}
> +__setup("ima_flush_htable", ima_flush_htable_setup);
> +
> /* pre-allocated array of tpm_digest structures to extend a PCR */
> static struct tpm_digest *digests;
>
> LIST_HEAD(ima_measurements); /* list of all measurements */
> +LIST_HEAD(ima_measurements_staged); /* list of staged measurements */
> +bool ima_measurements_staged_exist; /* If there are staged measurements */
> #ifdef CONFIG_IMA_KEXEC
> static unsigned long binary_runtime_size;
> +static unsigned long binary_runtime_size_notrim;
> #else
> static unsigned long binary_runtime_size = ULONG_MAX;
> +static unsigned long binary_runtime_size_notrim = ULONG_MAX;
> #endif
>
> /* key: inode (before secure-hashing a file) */
> struct ima_h_table ima_htable = {
> .len = ATOMIC_LONG_INIT(0),
> + .len_notrim = ATOMIC_LONG_INIT(0),
> .violations = ATOMIC_LONG_INIT(0),
> .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT
> };
> @@ -43,7 +56,7 @@ struct ima_h_table ima_htable = {
> * and extending the TPM PCR aggregate. Since tpm_extend can take
> * long (and the tpm driver uses a mutex), we can't use the spinlock.
> */
> -static DEFINE_MUTEX(ima_extend_list_mutex);
> +DEFINE_MUTEX(ima_extend_list_mutex);
>
> /*
> * Used internally by the kernel to suspend measurements.
> @@ -114,15 +127,19 @@ static int ima_add_digest_entry(struct ima_template_entry *entry,
> list_add_tail_rcu(&qe->later, &ima_measurements);
>
> atomic_long_inc(&ima_htable.len);
> + atomic_long_inc(&ima_htable.len_notrim);
> if (update_htable) {
> key = ima_hash_key(entry->digests[ima_hash_algo_idx].digest);
> hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
> }
>
> - if (binary_runtime_size != ULONG_MAX) {
> + if (binary_runtime_size_notrim != ULONG_MAX) {
> int size;
>
> size = get_binary_runtime_size(entry);
> + binary_runtime_size_notrim =
> + (binary_runtime_size_notrim < ULONG_MAX - size) ?
> + binary_runtime_size_notrim + size : ULONG_MAX;
> binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ?
> binary_runtime_size + size : ULONG_MAX;
> }
> @@ -134,12 +151,18 @@ static int ima_add_digest_entry(struct ima_template_entry *entry,
> * entire binary_runtime_measurement list, including the ima_kexec_hdr
> * structure.
> */
> -unsigned long ima_get_binary_runtime_size(void)
> +unsigned long ima_get_binary_runtime_size(bool notrim)
> {
> - if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
> + unsigned long *val;
> +
> + mutex_lock(&ima_extend_list_mutex);
> + val = (notrim) ? &binary_runtime_size_notrim : &binary_runtime_size;
> + mutex_unlock(&ima_extend_list_mutex);
> +
> + if (*val >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
> return ULONG_MAX;
> else
> - return binary_runtime_size + sizeof(struct ima_kexec_hdr);
> + return *val + sizeof(struct ima_kexec_hdr);
> }
>
> static int ima_pcr_extend(struct tpm_digest *digests_arg, int pcr)
> @@ -220,6 +243,84 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
> return result;
> }
>
> +int ima_queue_stage(unsigned long req_value)
> +{
> + unsigned long req_value_copy = req_value, to_remove = 0;
> + struct ima_queue_entry *qe;
> +
> + if (ima_measurements_staged_exist)
> + return -EEXIST;
> +
> + mutex_lock(&ima_extend_list_mutex);
> + if (list_empty(&ima_measurements)) {
> + mutex_unlock(&ima_extend_list_mutex);
> + return -ENOENT;
> + }
> +
> + if (req_value == ULONG_MAX) {
> + list_replace(&ima_measurements, &ima_measurements_staged);
> + INIT_LIST_HEAD(&ima_measurements);
> + atomic_long_set(&ima_htable.len, 0);
> + if (IS_ENABLED(CONFIG_IMA_KEXEC))
> + binary_runtime_size = 0;
> + } else {
> + list_for_each_entry(qe, &ima_measurements, later) {
> + to_remove += get_binary_runtime_size(qe->entry);
> + if (--req_value_copy == 0)
> + break;
> + }
> +
> + if (req_value_copy > 0) {
> + mutex_unlock(&ima_extend_list_mutex);
> + return -ENOENT;
> + }
> +
> + __list_cut_position(&ima_measurements_staged, &ima_measurements,
> + &qe->later);
> + atomic_long_sub(req_value, &ima_htable.len);
> + if (IS_ENABLED(CONFIG_IMA_KEXEC))
> + binary_runtime_size -= to_remove;
> + }
> +
> + if (ima_flush_htable) {
> + list_for_each_entry(qe, &ima_measurements_staged, later)
> + /* It can race with ima_lookup_digest_entry(). */
> + hlist_del_rcu(&qe->hnext);
> + }
> +
> + mutex_unlock(&ima_extend_list_mutex);
> + ima_measurements_staged_exist = true;
> + return 0;
> +}
> +
> +int ima_queue_delete_staged(void)
> +{
> + struct ima_queue_entry *qe, *qe_tmp;
> + unsigned int i;
> +
> + if (!ima_measurements_staged_exist)
> + return -ENOENT;
> +
> + list_for_each_entry_safe(qe, qe_tmp, &ima_measurements_staged, later) {
> + for (i = 0; i < qe->entry->template_desc->num_fields; i++) {
> + kfree(qe->entry->template_data[i].data);
> + qe->entry->template_data[i].data = NULL;
> + qe->entry->template_data[i].len = 0;
> + }
> +
> + list_del(&qe->later);
> +
> + if (ima_flush_htable) {
> + kfree(qe->entry->digests);
> + kfree(qe->entry);
> + kfree(qe);
> + }
> + }
> +
> + ima_measurements_staged_exist = false;
> + return 0;
> +}
> +
> int ima_restore_measurement_entry(struct ima_template_entry *entry)
> {
> int result = 0;
^ permalink raw reply
* Re: [RFC][PATCH] ima: Add support for staging measurements for deletion
From: Roberto Sassu @ 2025-12-11 9:56 UTC (permalink / raw)
To: Gregory Lumen
Cc: corbet, zohar, dmitry.kasatkin, eric.snowberg, paul, jmorris,
serge, linux-doc, linux-kernel, linux-integrity,
linux-security-module, chenste, nramas, Roberto Sassu
In-Reply-To: <207fd6d7-53c-57bb-36d8-13a0902052d1@linux.microsoft.com>
On Wed, 2025-12-10 at 11:12 -0800, Gregory Lumen wrote:
> Roberto,
>
> The proposed approach appears to be workable. However, if our primary goal
> here is to enable UM to free kernel memory consumed by the IMA log with an
> absolute minimum of kernel functionality/change, then I would argue that
> the proposed Stage-then-delete approach still represents unnecessary
> complexity when compared to a trim-to-N solution. Specifically:
>
> - Any functional benefit offered through the introduction of a staged
> measurement list could be equally achieved in UM with a trim-to-N solution
> coupled with the proposed ima_measure_users counter for access locking.
Ok, let's quantify the complexity of each solution. Let's assume that
the IMA measurements list has M entries and you want to trim at N < M.
Staging:
1st. trim at N
(kernel)
1. list lock (write side) -> list replace (swap the heads) -> list unlock
2. read M -> file (file contains 0..M)
3. for each 0..M -> delete entry
(user)
1. for each 0..N in file -> replay PCR
2. trim at N (keep N + 1..M)
2nd. trim at O
(kernel)
1. list lock -> list replace (swap the heads) -> list unlock
2. read P -> file (file contains N + 1..P)
3. for each M + 1..P -> delete entry
(user)
1. for each N + 1..O in file -> replay PCR
2. trim at O (keep O + 1..P)
Trimming:
1st. trim at N
(kernel)
1. list lock (read side) -> for each 0..M -> read in file (file now contains 0..M) -> list unlock
(user)
1. for each 0..N -> replay PCR
2. discard N + 1..M
(kernel)
1. list lock (write side) -> for each 0..N -> trim -> list unlock
2nd. trim at O
(kernel)
1. list lock (read side) -> for each N + 1..P -> read in file (file now contains N + 1..P) -> list unlock
(user)
1. for each N + 1..O -> replay PCR
2. discard O + 1..P
(kernel)
1. list lock (write side) -> for each N + 1..O -> trim -> list unlock
You can try to optimize it a bit by prematurely ending the reading
before M and P, and by replaying the PCR on a partial buffer.
But still:
I just swap list heads in the hot path (still need to do the same for
the hash table, postponed to later), and do the free later once there
is no contention with new measurements.
In your case you are taking the lock and walking the list two times,
once as a reader and once as a writer, and discarding measurements in
user space that you already have.
I think your solution is more complex.
> - There exists a potential UM measurement-loss race condition introduced
> by the staging functionality that would not exist with a trim-to-N
> approach. (Occurs if a kexec call occurs after a UM agent has staged
> measurements for deletion, but has not completed copying them to
> userspace). This could be avoided by persisting staged measurements across
> kexec calls at the cost of making the proposed change larger.
The solution is to coordinate the staging with kexec in user space.
Roberto
^ permalink raw reply
* Re: [PATCH V2 1/1] IMA event log trimming
From: Roberto Sassu @ 2025-12-11 10:14 UTC (permalink / raw)
To: steven chen, linux-integrity
Cc: zohar, roberto.sassu, dmitry.kasatkin, eric.snowberg, corbet,
serge, paul, jmorris, linux-security-module, anirudhve,
gregorylumen, nramas, sushring, linux-doc
In-Reply-To: <20251210235314.3341-2-chenste@linux.microsoft.com>
On Wed, 2025-12-10 at 15:53 -0800, steven chen wrote:
> This patch is for trimming N entries of the IMA event logs. It will also
> cleaning the hash table if ima_flush_htable is set.
>
> It provides a userspace interface ima_trim_log that can be used to input
> number N to let kernel to trim N entries of IMA event logs. When read
> this interface, it returns number of entries trimmed last time.
I was trying to find a common solution for both approaches, and instead
you took part of my code and removed the part that you didn't like.
This is not nice.
Let's do the following. Please review my patch, and check if it makes
you achieve your goal. Then, please send follow-up patches with the
additional functionality you need (e.g. the new critical data
measurement entry).
Thanks
Roberto
> Signed-off-by: steven chen <chenste@linux.microsoft.com>
> ---
> .../admin-guide/kernel-parameters.txt | 4 +
> security/integrity/ima/ima.h | 2 +
> security/integrity/ima/ima_fs.c | 175 +++++++++++++++++-
> security/integrity/ima/ima_queue.c | 64 +++++++
> 4 files changed, 241 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index e92c0056e4e0..cd1a1d0bf0e2 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2197,6 +2197,10 @@
> Use the canonical format for the binary runtime
> measurements, instead of host native format.
>
> + ima_flush_htable [IMA]
> + Flush the measurement list hash table when trim all
> + or a part of it for deletion.
> +
> ima_hash= [IMA]
> Format: { md5 | sha1 | rmd160 | sha256 | sha384
> | sha512 | ... }
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index e3d71d8d56e3..ab0e30ee25ea 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -246,8 +246,10 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key,
>
> #ifdef CONFIG_IMA_KEXEC
> void ima_measure_kexec_event(const char *event_name);
> +long ima_purge_event_log(long number_logs);
> #else
> static inline void ima_measure_kexec_event(const char *event_name) {}
> +static inline long ima_purge_event_log(long number_logs) { return 0; }
> #endif
>
> /*
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index 87045b09f120..410f7d03c43f 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -21,6 +21,9 @@
> #include <linux/rcupdate.h>
> #include <linux/parser.h>
> #include <linux/vmalloc.h>
> +#include <linux/ktime.h>
> +#include <linux/timekeeping.h>
> +#include <linux/ima.h>
>
> #include "ima.h"
>
> @@ -38,6 +41,14 @@ __setup("ima_canonical_fmt", default_canonical_fmt_setup);
>
> static int valid_policy = 1;
>
> +#define IMA_LOG_TRIM_REQ_LENGTH 11
> +#define IMA_LOG_TRIM_EVENT_LEN 256
> +
> +static long trimcount;
> +/* mutex protects atomicity of trimming measurement list requests */
> +static DEFINE_MUTEX(ima_measure_lock);
> +static long ima_measure_users;
> +
> static ssize_t ima_show_htable_value(char __user *buf, size_t count,
> loff_t *ppos, atomic_long_t *val)
> {
> @@ -202,16 +213,65 @@ static const struct seq_operations ima_measurments_seqops = {
> .show = ima_measurements_show
> };
>
> +static int _ima_measurements_open(struct inode *inode, struct file *file,
> + const struct seq_operations *seq_ops)
> +{
> + bool write = !!(file->f_mode & FMODE_WRITE);
> + int ret;
> +
> + if (write && !capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + mutex_lock(&ima_measure_lock);
> + if ((write && ima_measure_users != 0) ||
> + (!write && ima_measure_users < 0)) {
> + mutex_unlock(&ima_measure_lock);
> + return -EBUSY;
> + }
> +
> + ret = seq_open(file, seq_ops);
> + if (ret < 0) {
> + mutex_unlock(&ima_measure_lock);
> + return ret;
> + }
> +
> + if (write)
> + ima_measure_users--;
> + else
> + ima_measure_users++;
> +
> + mutex_unlock(&ima_measure_lock);
> + return ret;
> +}
> +
> static int ima_measurements_open(struct inode *inode, struct file *file)
> {
> - return seq_open(file, &ima_measurments_seqops);
> + return _ima_measurements_open(inode, file, &ima_measurments_seqops);
> +}
> +
> +static int ima_measurements_release(struct inode *inode, struct file *file)
> +{
> + bool write = !!(file->f_mode & FMODE_WRITE);
> + int ret;
> +
> + mutex_lock(&ima_measure_lock);
> + ret = seq_release(inode, file);
> + if (!ret) {
> + if (write)
> + ima_measure_users++;
> + else
> + ima_measure_users--;
> + }
> +
> + mutex_unlock(&ima_measure_lock);
> + return ret;
> }
>
> static const struct file_operations ima_measurements_ops = {
> .open = ima_measurements_open,
> .read = seq_read,
> .llseek = seq_lseek,
> - .release = seq_release,
> + .release = ima_measurements_release,
> };
>
> void ima_print_digest(struct seq_file *m, u8 *digest, u32 size)
> @@ -279,14 +339,111 @@ static const struct seq_operations ima_ascii_measurements_seqops = {
>
> static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
> {
> - return seq_open(file, &ima_ascii_measurements_seqops);
> + return _ima_measurements_open(inode, file, &ima_ascii_measurements_seqops);
> }
>
> static const struct file_operations ima_ascii_measurements_ops = {
> .open = ima_ascii_measurements_open,
> .read = seq_read,
> .llseek = seq_lseek,
> - .release = seq_release,
> + .release = ima_measurements_release,
> +};
> +
> +static void ima_measure_trim_event(const long number_logs)
> +{
> + char ima_log_trim_event[IMA_LOG_TRIM_EVENT_LEN];
> + struct timespec64 ts;
> + u64 time_ns;
> + int n;
> +
> + ktime_get_real_ts64(&ts);
> + time_ns = (u64)ts.tv_sec * 1000000000ULL + ts.tv_nsec;
> + n = scnprintf(ima_log_trim_event, IMA_LOG_TRIM_EVENT_LEN,
> + "time=%llu; log trim this time=%lu;",
> + time_ns, number_logs);
> +
> + ima_measure_critical_data("ima_log_trim", "trim ima event logs", ima_log_trim_event, n, false, NULL, 0);
> +}
> +
> +static int ima_log_trim_open(struct inode *inode, struct file *file)
> +{
> + bool write = !!(file->f_mode & FMODE_WRITE);
> +
> + if (!write && capable(CAP_SYS_ADMIN))
> + return 0;
> + else if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + return _ima_measurements_open(inode, file, &ima_measurments_seqops);
> +}
> +
> +static ssize_t ima_log_trim_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
> +{
> + char tmpbuf[IMA_LOG_TRIM_REQ_LENGTH]; /* greater than largest 'long' string value */
> + ssize_t len;
> +
> + len = scnprintf(tmpbuf, sizeof(tmpbuf), "%li\n", trimcount);
> + return simple_read_from_buffer(buf, size, ppos, tmpbuf, len);
> +}
> +
> +static ssize_t ima_log_trim_write(struct file *file,
> + const char __user *buf, size_t datalen, loff_t *ppos)
> +{
> + unsigned char req[IMA_LOG_TRIM_REQ_LENGTH];
> + long count, n;
> + int ret;
> +
> + if (*ppos > 0 || datalen > IMA_LOG_TRIM_REQ_LENGTH || datalen < 2) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + n = (int)datalen;
> +
> + ret = copy_from_user(req, buf, datalen);
> + if (ret < 0)
> + goto out;
> +
> + count = 0;
> + for (int i = 0; i < n; ++i) {
> + if (req[i] < '0' || req[i] > '9') {
> + ret = -EINVAL;
> + goto out;
> + }
> + count = count * 10 + req[i] - '0';
> + }
> + ret = ima_purge_event_log(count);
> +
> + if (ret < 0)
> + goto out;
> +
> + trimcount = ret;
> +
> + if (trimcount > 0)
> + ima_measure_trim_event(trimcount);
> +
> + ret = datalen;
> +out:
> + return ret;
> +}
> +
> +static int ima_log_trim_release(struct inode *inode, struct file *file)
> +{
> + bool write = !!(file->f_mode & FMODE_WRITE);
> + if (!write && capable(CAP_SYS_ADMIN))
> + return 0;
> + else if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + return ima_measurements_release(inode, file);
> +}
> +
> +static const struct file_operations ima_log_trim_ops = {
> + .open = ima_log_trim_open,
> + .read = ima_log_trim_read,
> + .write = ima_log_trim_write,
> + .llseek = generic_file_llseek,
> + .release = ima_log_trim_release
> };
>
> static ssize_t ima_read_policy(char *path)
> @@ -528,6 +685,16 @@ int __init ima_fs_init(void)
> goto out;
> }
>
> + dentry = securityfs_create_file("ima_trim_log",
> + S_IRUSR | S_IRGRP | S_IWUSR | S_IWGRP,
> + ima_dir, NULL, &ima_log_trim_ops);
> + if (IS_ERR(dentry)) {
> + ret = PTR_ERR(dentry);
> + goto out;
> + }
> +
> + trimcount = 0;
> +
> dentry = securityfs_create_file("runtime_measurements_count",
> S_IRUSR | S_IRGRP, ima_dir, NULL,
> &ima_measurements_count_ops);
> diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
> index 590637e81ad1..77ab52469727 100644
> --- a/security/integrity/ima/ima_queue.c
> +++ b/security/integrity/ima/ima_queue.c
> @@ -22,6 +22,14 @@
>
> #define AUDIT_CAUSE_LEN_MAX 32
>
> +bool ima_flush_htable;
> +static int __init ima_flush_htable_setup(char *str)
> +{
> + ima_flush_htable = true;
> + return 1;
> +}
> +__setup("ima_flush_htable", ima_flush_htable_setup);
> +
> /* pre-allocated array of tpm_digest structures to extend a PCR */
> static struct tpm_digest *digests;
>
> @@ -220,6 +228,62 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
> return result;
> }
>
> +/* Delete the IMA event logs */
> +long ima_purge_event_log(long number_logs)
> +{
> + struct ima_queue_entry *qe, *qe_tmp;
> + LIST_HEAD(ima_measurements_staged);
> + unsigned int i;
> + long cur = number_logs;
> +
> + if (number_logs <= 0)
> + return number_logs;
> +
> + mutex_lock(&ima_extend_list_mutex);
> +
> +
> + list_for_each_entry(qe, &ima_measurements, later) {
> + if (--number_logs == 0)
> + break;
> + }
> +
> + if (number_logs > 0) {
> + mutex_unlock(&ima_extend_list_mutex);
> + return -ENOENT;
> + }
> +
> + __list_cut_position(&ima_measurements_staged, &ima_measurements,
> + &qe->later);
> + atomic_long_sub(cur, &ima_htable.len);
> +
> + if (!IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE) && ima_flush_htable) {
> + list_for_each_entry(qe, &ima_measurements_staged, later)
> + /* It can race with ima_lookup_digest_entry(). */
> + hlist_del_rcu(&qe->hnext);
> + }
> +
> + mutex_unlock(&ima_extend_list_mutex);
> +
> +
> + list_for_each_entry_safe(qe, qe_tmp, &ima_measurements_staged, later) {
> + for (i = 0; i < qe->entry->template_desc->num_fields; i++) {
> + kfree(qe->entry->template_data[i].data);
> + qe->entry->template_data[i].data = NULL;
> + qe->entry->template_data[i].len = 0;
> + }
> +
> + list_del(&qe->later);
> +
> + if (ima_flush_htable) {
> + kfree(qe->entry->digests);
> + kfree(qe->entry);
> + kfree(qe);
> + }
> + }
> +
> + return cur;
> +}
> +
> int ima_restore_measurement_entry(struct ima_template_entry *entry)
> {
> int result = 0;
^ permalink raw reply
* Re: [RFC][PATCH] ima: Add support for staging measurements for deletion
From: Roberto Sassu @ 2025-12-11 10:18 UTC (permalink / raw)
To: steven chen, corbet, zohar, dmitry.kasatkin, eric.snowberg, paul,
jmorris, serge
Cc: linux-doc, linux-kernel, linux-integrity, linux-security-module,
gregorylumen, nramas, Roberto Sassu
In-Reply-To: <9cb4cbab-bcca-4ac8-a7a5-0cf3de67353e@linux.microsoft.com>
On Wed, 2025-12-10 at 16:03 -0800, steven chen wrote:
> On 12/9/2025 2:17 AM, Roberto Sassu wrote:
> > From: Roberto Sassu <roberto.sassu@huawei.com>
> >
> > Introduce the ability of staging the entire of the IMA measurement list, or
> > a portion, for deletion. Staging means moving the current content of the
> > measurement list to a separate location, and allowing users to read and
> > delete it. This causes the measurement list to be atomically truncated
> > before new measurements can be added. Staging can be done only once at a
> > time.
> >
> > User space is responsible to concatenate the staged IMA measurements list
> > portions following the temporal order in which the operations were done,
> > together with the current measurement list. Then, it can send the collected
> > data to the remote verifiers.
> >
> > The benefit of this solution is the ability to free precious kernel memory,
> > in exchange of delegating user space to reconstruct the full measurement
> > list from the chunks. No trust needs to be given to user space, since the
> > integrity of the measurement list is protected by the TPM.
> >
> > By default, staging the measurements list for deletion does not alter the
> > hash table. When staging is done, IMA is still able to detect collisions on
> > the staged and later deleted measurement entries, by keeping the entry
> > digests (only template data are freed).
> >
> > However, since during the measurements list serialization only the SHA1
> > digest is passed, and since there are no template data to recalculate the
> > other digests from, the hash table is currently not populated with digests
> > from staged/deleted entries after kexec().
> >
> > Introduce the new kernel option ima_flush_htable to decide whether or not
> > the digests of staged measurement entries are flushed from the hash table.
> >
> > Then, introduce ascii_runtime_measurements_staged_<algo> and
> > binary_runtime_measurement_staged_<algo> interfaces to stage/delete the
> > measurements. Use 'echo A > <IMA interface>' and 'echo D > <IMA interface>'
> > to respectively stage and delete the entire measurements list. Use
> > 'echo N > <IMA interface>', with N between 1 and ULONG_MAX, to stage the
> > selected portion of the measurements list.
> >
> > The ima_measure_users counter (protected by the ima_measure_lock mutex) has
> > been introduced to protect access to the measurement list and the staged
> > part. The open method of all the measurement interfaces has been extended
> > to allow only one writer at a time or, in alternative, multiple readers.
> > The write permission is used to stage/delete the measurements, the read
> > permission to read them. Write requires also the CAP_SYS_ADMIN capability.
>
> Hi Roberto,
>
> I released version 2 of trim N entries patch as bellow:
>
> [PATCH v2 0/1] Trim N entries of IMA event logs
> <https://lore.kernel.org/linux-integrity/20251210235314.3341-1-chenste@linux.microsoft.com/T/#t>
>
> I adapted some of your idea and I think trim N has following advantages:
> 1: less measurement list hold time than your current implementation
> 2. operation much simple for user space
> 3. less kernel code change
> 4. no potential issue as Gregory mentioned.
Please have a look at:
https://marc.info/?l=linux-integrity&m=176545085325473&w=2
and let me know if I'm missing something.
Thanks
Roberto
> Thanks,
>
> Steven
>
> > Finally, introduce the _notrim version of the run-time measurements count
> > and the binary measurements list size, to display them in the kexec-related
> > critical data records.
> >
> > Note: This code derives from the Alt-IMA Huawei project, and is being
> > released under the dual license model (GPL-2.0 OR MIT).
> >
> > Link: https://github.com/linux-integrity/linux/issues/1
> > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > ---
> > .../admin-guide/kernel-parameters.txt | 4 +
> > security/integrity/ima/ima.h | 10 +-
> > security/integrity/ima/ima_fs.c | 222 +++++++++++++++++-
> > security/integrity/ima/ima_kexec.c | 13 +-
> > security/integrity/ima/ima_queue.c | 111 ++++++++-
> > 5 files changed, 340 insertions(+), 20 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index 6c42061ca20e..355d8930e3ac 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -2215,6 +2215,10 @@
> > Use the canonical format for the binary runtime
> > measurements, instead of host native format.
> >
> > + ima_flush_htable [IMA]
> > + Flush the measurement list hash table when staging all
> > + or a part of it for deletion.
> > +
> > ima_hash= [IMA]
> > Format: { md5 | sha1 | rmd160 | sha256 | sha384
> > | sha512 | ... }
> > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> > index e3d71d8d56e3..d7aa4a0f79b1 100644
> > --- a/security/integrity/ima/ima.h
> > +++ b/security/integrity/ima/ima.h
> > @@ -117,6 +117,8 @@ struct ima_queue_entry {
> > struct ima_template_entry *entry;
> > };
> > extern struct list_head ima_measurements; /* list of all measurements */
> > +extern struct list_head ima_measurements_staged; /* list of staged meas. */
> > +extern bool ima_measurements_staged_exist; /* If there are staged meas. */
> >
> > /* Some details preceding the binary serialized measurement list */
> > struct ima_kexec_hdr {
> > @@ -281,10 +283,12 @@ struct ima_template_desc *ima_template_desc_current(void);
> > struct ima_template_desc *ima_template_desc_buf(void);
> > struct ima_template_desc *lookup_template_desc(const char *name);
> > bool ima_template_has_modsig(const struct ima_template_desc *ima_template);
> > +int ima_queue_stage(unsigned long req_value);
> > +int ima_queue_delete_staged(void);
> > int ima_restore_measurement_entry(struct ima_template_entry *entry);
> > int ima_restore_measurement_list(loff_t bufsize, void *buf);
> > int ima_measurements_show(struct seq_file *m, void *v);
> > -unsigned long ima_get_binary_runtime_size(void);
> > +unsigned long ima_get_binary_runtime_size(bool notrim);
> > int ima_init_template(void);
> > void ima_init_template_list(void);
> > int __init ima_init_digests(void);
> > @@ -298,11 +302,13 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
> > extern spinlock_t ima_queue_lock;
> >
> > struct ima_h_table {
> > - atomic_long_t len; /* number of stored measurements in the list */
> > + atomic_long_t len; /* current num of stored meas. in the list */
> > + atomic_long_t len_notrim; /* total num of stored meas. in the list */
> > atomic_long_t violations;
> > struct hlist_head queue[IMA_MEASURE_HTABLE_SIZE];
> > };
> > extern struct ima_h_table ima_htable;
> > +extern struct mutex ima_extend_list_mutex;
> >
> > static inline unsigned int ima_hash_key(u8 *digest)
> > {
> > diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> > index 87045b09f120..321c98ae0e55 100644
> > --- a/security/integrity/ima/ima_fs.c
> > +++ b/security/integrity/ima/ima_fs.c
> > @@ -24,7 +24,12 @@
> >
> > #include "ima.h"
> >
> > +/* Requests: ('A', [1, ULONG_MAX])\n (stage all/N) or D\n (delete staged) */
> > +#define STAGED_REQ_LENGTH 21
> > +
> > static DEFINE_MUTEX(ima_write_mutex);
> > +static DEFINE_MUTEX(ima_measure_lock);
> > +static long ima_measure_users;
> >
> > bool ima_canonical_fmt;
> > static int __init default_canonical_fmt_setup(char *str)
> > @@ -74,14 +79,15 @@ static const struct file_operations ima_measurements_count_ops = {
> > };
> >
> > /* returns pointer to hlist_node */
> > -static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
> > +static void *_ima_measurements_start(struct seq_file *m, loff_t *pos,
> > + struct list_head *head)
> > {
> > loff_t l = *pos;
> > struct ima_queue_entry *qe;
> >
> > /* we need a lock since pos could point beyond last element */
> > rcu_read_lock();
> > - list_for_each_entry_rcu(qe, &ima_measurements, later) {
> > + list_for_each_entry_rcu(qe, head, later) {
> > if (!l--) {
> > rcu_read_unlock();
> > return qe;
> > @@ -91,7 +97,18 @@ static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
> > return NULL;
> > }
> >
> > -static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
> > +static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
> > +{
> > + return _ima_measurements_start(m, pos, &ima_measurements);
> > +}
> > +
> > +static void *ima_measurements_staged_start(struct seq_file *m, loff_t *pos)
> > +{
> > + return _ima_measurements_start(m, pos, &ima_measurements_staged);
> > +}
> > +
> > +static void *_ima_measurements_next(struct seq_file *m, void *v, loff_t *pos,
> > + struct list_head *head)
> > {
> > struct ima_queue_entry *qe = v;
> >
> > @@ -103,7 +120,18 @@ static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
> > rcu_read_unlock();
> > (*pos)++;
> >
> > - return (&qe->later == &ima_measurements) ? NULL : qe;
> > + return (&qe->later == head) ? NULL : qe;
> > +}
> > +
> > +static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
> > +{
> > + return _ima_measurements_next(m, v, pos, &ima_measurements);
> > +}
> > +
> > +static void *ima_measurements_staged_next(struct seq_file *m, void *v,
> > + loff_t *pos)
> > +{
> > + return _ima_measurements_next(m, v, pos, &ima_measurements_staged);
> > }
> >
> > static void ima_measurements_stop(struct seq_file *m, void *v)
> > @@ -202,16 +230,138 @@ static const struct seq_operations ima_measurments_seqops = {
> > .show = ima_measurements_show
> > };
> >
> > +static int _ima_measurements_open(struct inode *inode, struct file *file,
> > + const struct seq_operations *seq_ops)
> > +{
> > + bool write = !!(file->f_mode & FMODE_WRITE);
> > + int ret;
> > +
> > + if (write && !capable(CAP_SYS_ADMIN))
> > + return -EPERM;
> > +
> > + mutex_lock(&ima_measure_lock);
> > + if ((write && ima_measure_users != 0) ||
> > + (!write && ima_measure_users < 0)) {
> > + mutex_unlock(&ima_measure_lock);
> > + return -EBUSY;
> > + }
> > +
> > + ret = seq_open(file, seq_ops);
> > + if (ret < 0) {
> > + mutex_unlock(&ima_measure_lock);
> > + return ret;
> > + }
> > +
> > + if (write)
> > + ima_measure_users--;
> > + else
> > + ima_measure_users++;
> > +
> > + mutex_unlock(&ima_measure_lock);
> > + return ret;
> > +}
> > +
> > static int ima_measurements_open(struct inode *inode, struct file *file)
> > {
> > - return seq_open(file, &ima_measurments_seqops);
> > + return _ima_measurements_open(inode, file, &ima_measurments_seqops);
> > +}
> > +
> > +static int ima_measurements_release(struct inode *inode, struct file *file)
> > +{
> > + bool write = !!(file->f_mode & FMODE_WRITE);
> > + int ret;
> > +
> > + mutex_lock(&ima_measure_lock);
> > + ret = seq_release(inode, file);
> > + if (!ret) {
> > + if (write)
> > + ima_measure_users++;
> > + else
> > + ima_measure_users--;
> > + }
> > +
> > + mutex_unlock(&ima_measure_lock);
> > + return ret;
> > }
> >
> > static const struct file_operations ima_measurements_ops = {
> > .open = ima_measurements_open,
> > .read = seq_read,
> > .llseek = seq_lseek,
> > - .release = seq_release,
> > + .release = ima_measurements_release,
> > +};
> > +
> > +static const struct seq_operations ima_measurments_staged_seqops = {
> > + .start = ima_measurements_staged_start,
> > + .next = ima_measurements_staged_next,
> > + .stop = ima_measurements_stop,
> > + .show = ima_measurements_show
> > +};
> > +
> > +static int ima_measurements_staged_open(struct inode *inode, struct file *file)
> > +{
> > + return _ima_measurements_open(inode, file,
> > + &ima_measurments_staged_seqops);
> > +}
> > +
> > +static ssize_t ima_measurements_staged_read(struct file *file, char __user *buf,
> > + size_t size, loff_t *ppos)
> > +{
> > + if (!ima_measurements_staged_exist)
> > + return -ENOENT;
> > +
> > + return seq_read(file, buf, size, ppos);
> > +}
> > +
> > +static ssize_t ima_measurements_staged_write(struct file *file,
> > + const char __user *buf,
> > + size_t datalen, loff_t *ppos)
> > +{
> > + char req[STAGED_REQ_LENGTH], *req_ptr = req;
> > + unsigned long req_value;
> > + int ret;
> > +
> > + if (*ppos > 0 || datalen < 2 || datalen > STAGED_REQ_LENGTH)
> > + return -EINVAL;
> > +
> > + ret = copy_from_user(req, buf, datalen);
> > + if (ret < 0)
> > + return ret;
> > +
> > + if (strsep(&req_ptr, "\n") == NULL)
> > + return -EINVAL;
> > +
> > + switch (req[0]) {
> > + case 'A':
> > + if (datalen != 2 || req[1] != '\0')
> > + return -EINVAL;
> > +
> > + ret = ima_queue_stage(ULONG_MAX);
> > + break;
> > + case 'D':
> > + if (datalen != 2 || req[1] != '\0')
> > + return -EINVAL;
> > +
> > + ret = ima_queue_delete_staged();
> > + break;
> > + default:
> > + ret = kstrtoul(req, 0, &req_value);
> > + if (!ret)
> > + ret = ima_queue_stage(req_value);
> > + }
> > +
> > + if (ret < 0)
> > + return ret;
> > +
> > + return datalen;
> > +}
> > +
> > +static const struct file_operations ima_measurements_staged_ops = {
> > + .open = ima_measurements_staged_open,
> > + .read = ima_measurements_staged_read,
> > + .write = ima_measurements_staged_write,
> > + .llseek = seq_lseek,
> > + .release = ima_measurements_release,
> > };
> >
> > void ima_print_digest(struct seq_file *m, u8 *digest, u32 size)
> > @@ -279,14 +429,37 @@ static const struct seq_operations ima_ascii_measurements_seqops = {
> >
> > static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
> > {
> > - return seq_open(file, &ima_ascii_measurements_seqops);
> > + return _ima_measurements_open(inode, file,
> > + &ima_ascii_measurements_seqops);
> > }
> >
> > static const struct file_operations ima_ascii_measurements_ops = {
> > .open = ima_ascii_measurements_open,
> > .read = seq_read,
> > .llseek = seq_lseek,
> > - .release = seq_release,
> > + .release = ima_measurements_release,
> > +};
> > +
> > +static const struct seq_operations ima_ascii_measurements_staged_seqops = {
> > + .start = ima_measurements_staged_start,
> > + .next = ima_measurements_staged_next,
> > + .stop = ima_measurements_stop,
> > + .show = ima_ascii_measurements_show
> > +};
> > +
> > +static int ima_ascii_measurements_staged_open(struct inode *inode,
> > + struct file *file)
> > +{
> > + return _ima_measurements_open(inode, file,
> > + &ima_ascii_measurements_staged_seqops);
> > +}
> > +
> > +static const struct file_operations ima_ascii_measurements_staged_ops = {
> > + .open = ima_ascii_measurements_staged_open,
> > + .read = ima_measurements_staged_read,
> > + .write = ima_measurements_staged_write,
> > + .llseek = seq_lseek,
> > + .release = ima_measurements_release,
> > };
> >
> > static ssize_t ima_read_policy(char *path)
> > @@ -419,6 +592,25 @@ static int __init create_securityfs_measurement_lists(void)
> > &ima_measurements_ops);
> > if (IS_ERR(dentry))
> > return PTR_ERR(dentry);
> > +
> > + sprintf(file_name, "ascii_runtime_measurements_staged_%s",
> > + hash_algo_name[algo]);
> > + dentry = securityfs_create_file(file_name,
> > + S_IRUSR | S_IRGRP | S_IWUSR | S_IWGRP,
> > + ima_dir, (void *)(uintptr_t)i,
> > + &ima_ascii_measurements_staged_ops);
> > + if (IS_ERR(dentry))
> > + return PTR_ERR(dentry);
> > +
> > + sprintf(file_name, "binary_runtime_measurements_staged_%s",
> > + hash_algo_name[algo]);
> > + dentry = securityfs_create_file(file_name,
> > + S_IRUSR | S_IRGRP |
> > + S_IWUSR | S_IWGRP,
> > + ima_dir, (void *)(uintptr_t)i,
> > + &ima_measurements_staged_ops);
> > + if (IS_ERR(dentry))
> > + return PTR_ERR(dentry);
> > }
> >
> > return 0;
> > @@ -528,6 +720,20 @@ int __init ima_fs_init(void)
> > goto out;
> > }
> >
> > + dentry = securityfs_create_symlink("binary_runtime_measurements_staged",
> > + ima_dir, "binary_runtime_measurements_staged_sha1", NULL);
> > + if (IS_ERR(dentry)) {
> > + ret = PTR_ERR(dentry);
> > + goto out;
> > + }
> > +
> > + dentry = securityfs_create_symlink("ascii_runtime_measurements_staged",
> > + ima_dir, "ascii_runtime_measurements_staged_sha1", NULL);
> > + if (IS_ERR(dentry)) {
> > + ret = PTR_ERR(dentry);
> > + goto out;
> > + }
> > +
> > dentry = securityfs_create_file("runtime_measurements_count",
> > S_IRUSR | S_IRGRP, ima_dir, NULL,
> > &ima_measurements_count_ops);
> > diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
> > index 7362f68f2d8b..23a20300da7b 100644
> > --- a/security/integrity/ima/ima_kexec.c
> > +++ b/security/integrity/ima/ima_kexec.c
> > @@ -40,8 +40,8 @@ void ima_measure_kexec_event(const char *event_name)
> > long len;
> > int n;
> >
> > - buf_size = ima_get_binary_runtime_size();
> > - len = atomic_long_read(&ima_htable.len);
> > + buf_size = ima_get_binary_runtime_size(true);
> > + len = atomic_long_read(&ima_htable.len_notrim);
> >
> > n = scnprintf(ima_kexec_event, IMA_KEXEC_EVENT_LEN,
> > "kexec_segment_size=%lu;ima_binary_runtime_size=%lu;"
> > @@ -93,8 +93,10 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
> >
> > memset(&khdr, 0, sizeof(khdr));
> > khdr.version = 1;
> > - /* This is an append-only list, no need to hold the RCU read lock */
> > - list_for_each_entry_rcu(qe, &ima_measurements, later, true) {
> > +
> > + /* It can race with ima_queue_stage(). */
> > + mutex_lock(&ima_extend_list_mutex);
> > + list_for_each_entry(qe, &ima_measurements, later) {
> > if (ima_kexec_file.count < ima_kexec_file.size) {
> > khdr.count++;
> > ima_measurements_show(&ima_kexec_file, qe);
> > @@ -103,6 +105,7 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
> > break;
> > }
> > }
> > + mutex_unlock(&ima_extend_list_mutex);
> >
> > /*
> > * fill in reserved space with some buffer details
> > @@ -157,7 +160,7 @@ void ima_add_kexec_buffer(struct kimage *image)
> > else
> > extra_memory = CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB * 1024;
> >
> > - binary_runtime_size = ima_get_binary_runtime_size() + extra_memory;
> > + binary_runtime_size = ima_get_binary_runtime_size(false) + extra_memory;
> >
> > if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE)
> > kexec_segment_size = ULONG_MAX;
> > diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
> > index 590637e81ad1..868f216ac343 100644
> > --- a/security/integrity/ima/ima_queue.c
> > +++ b/security/integrity/ima/ima_queue.c
> > @@ -22,19 +22,32 @@
> >
> > #define AUDIT_CAUSE_LEN_MAX 32
> >
> > +bool ima_flush_htable;
> > +static int __init ima_flush_htable_setup(char *str)
> > +{
> > + ima_flush_htable = true;
> > + return 1;
> > +}
> > +__setup("ima_flush_htable", ima_flush_htable_setup);
> > +
> > /* pre-allocated array of tpm_digest structures to extend a PCR */
> > static struct tpm_digest *digests;
> >
> > LIST_HEAD(ima_measurements); /* list of all measurements */
> > +LIST_HEAD(ima_measurements_staged); /* list of staged measurements */
> > +bool ima_measurements_staged_exist; /* If there are staged measurements */
> > #ifdef CONFIG_IMA_KEXEC
> > static unsigned long binary_runtime_size;
> > +static unsigned long binary_runtime_size_notrim;
> > #else
> > static unsigned long binary_runtime_size = ULONG_MAX;
> > +static unsigned long binary_runtime_size_notrim = ULONG_MAX;
> > #endif
> >
> > /* key: inode (before secure-hashing a file) */
> > struct ima_h_table ima_htable = {
> > .len = ATOMIC_LONG_INIT(0),
> > + .len_notrim = ATOMIC_LONG_INIT(0),
> > .violations = ATOMIC_LONG_INIT(0),
> > .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT
> > };
> > @@ -43,7 +56,7 @@ struct ima_h_table ima_htable = {
> > * and extending the TPM PCR aggregate. Since tpm_extend can take
> > * long (and the tpm driver uses a mutex), we can't use the spinlock.
> > */
> > -static DEFINE_MUTEX(ima_extend_list_mutex);
> > +DEFINE_MUTEX(ima_extend_list_mutex);
> >
> > /*
> > * Used internally by the kernel to suspend measurements.
> > @@ -114,15 +127,19 @@ static int ima_add_digest_entry(struct ima_template_entry *entry,
> > list_add_tail_rcu(&qe->later, &ima_measurements);
> >
> > atomic_long_inc(&ima_htable.len);
> > + atomic_long_inc(&ima_htable.len_notrim);
> > if (update_htable) {
> > key = ima_hash_key(entry->digests[ima_hash_algo_idx].digest);
> > hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
> > }
> >
> > - if (binary_runtime_size != ULONG_MAX) {
> > + if (binary_runtime_size_notrim != ULONG_MAX) {
> > int size;
> >
> > size = get_binary_runtime_size(entry);
> > + binary_runtime_size_notrim =
> > + (binary_runtime_size_notrim < ULONG_MAX - size) ?
> > + binary_runtime_size_notrim + size : ULONG_MAX;
> > binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ?
> > binary_runtime_size + size : ULONG_MAX;
> > }
> > @@ -134,12 +151,18 @@ static int ima_add_digest_entry(struct ima_template_entry *entry,
> > * entire binary_runtime_measurement list, including the ima_kexec_hdr
> > * structure.
> > */
> > -unsigned long ima_get_binary_runtime_size(void)
> > +unsigned long ima_get_binary_runtime_size(bool notrim)
> > {
> > - if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
> > + unsigned long *val;
> > +
> > + mutex_lock(&ima_extend_list_mutex);
> > + val = (notrim) ? &binary_runtime_size_notrim : &binary_runtime_size;
> > + mutex_unlock(&ima_extend_list_mutex);
> > +
> > + if (*val >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
> > return ULONG_MAX;
> > else
> > - return binary_runtime_size + sizeof(struct ima_kexec_hdr);
> > + return *val + sizeof(struct ima_kexec_hdr);
> > }
> >
> > static int ima_pcr_extend(struct tpm_digest *digests_arg, int pcr)
> > @@ -220,6 +243,84 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
> > return result;
> > }
> >
> > +int ima_queue_stage(unsigned long req_value)
> > +{
> > + unsigned long req_value_copy = req_value, to_remove = 0;
> > + struct ima_queue_entry *qe;
> > +
> > + if (ima_measurements_staged_exist)
> > + return -EEXIST;
> > +
> > + mutex_lock(&ima_extend_list_mutex);
> > + if (list_empty(&ima_measurements)) {
> > + mutex_unlock(&ima_extend_list_mutex);
> > + return -ENOENT;
> > + }
> > +
> > + if (req_value == ULONG_MAX) {
> > + list_replace(&ima_measurements, &ima_measurements_staged);
> > + INIT_LIST_HEAD(&ima_measurements);
> > + atomic_long_set(&ima_htable.len, 0);
> > + if (IS_ENABLED(CONFIG_IMA_KEXEC))
> > + binary_runtime_size = 0;
> > + } else {
> > + list_for_each_entry(qe, &ima_measurements, later) {
> > + to_remove += get_binary_runtime_size(qe->entry);
> > + if (--req_value_copy == 0)
> > + break;
> > + }
> > +
> > + if (req_value_copy > 0) {
> > + mutex_unlock(&ima_extend_list_mutex);
> > + return -ENOENT;
> > + }
> > +
> > + __list_cut_position(&ima_measurements_staged, &ima_measurements,
> > + &qe->later);
> > + atomic_long_sub(req_value, &ima_htable.len);
> > + if (IS_ENABLED(CONFIG_IMA_KEXEC))
> > + binary_runtime_size -= to_remove;
> > + }
> > +
> > + if (ima_flush_htable) {
> > + list_for_each_entry(qe, &ima_measurements_staged, later)
> > + /* It can race with ima_lookup_digest_entry(). */
> > + hlist_del_rcu(&qe->hnext);
> > + }
> > +
> > + mutex_unlock(&ima_extend_list_mutex);
> > + ima_measurements_staged_exist = true;
> > + return 0;
> > +}
> > +
> > +int ima_queue_delete_staged(void)
> > +{
> > + struct ima_queue_entry *qe, *qe_tmp;
> > + unsigned int i;
> > +
> > + if (!ima_measurements_staged_exist)
> > + return -ENOENT;
> > +
> > + list_for_each_entry_safe(qe, qe_tmp, &ima_measurements_staged, later) {
> > + for (i = 0; i < qe->entry->template_desc->num_fields; i++) {
> > + kfree(qe->entry->template_data[i].data);
> > + qe->entry->template_data[i].data = NULL;
> > + qe->entry->template_data[i].len = 0;
> > + }
> > +
> > + list_del(&qe->later);
> > +
> > + if (ima_flush_htable) {
> > + kfree(qe->entry->digests);
> > + kfree(qe->entry);
> > + kfree(qe);
> > + }
> > + }
> > +
> > + ima_measurements_staged_exist = false;
> > + return 0;
> > +}
> > +
> > int ima_restore_measurement_entry(struct ima_template_entry *entry)
> > {
> > int result = 0;
>
^ permalink raw reply
* Re: [LTP] [PATCH v4 0/4] tst_runas.c, ima_{conditionals, measurements}.sh enhancements
From: Andrea Cervesato @ 2025-12-11 10:37 UTC (permalink / raw)
To: Petr Vorel, ltp; +Cc: selinux, linux-integrity
In-Reply-To: <20251209185557.20598-1-pvorel@suse.cz>
Hi Petr,
thanks for adding this tool. We will probably need to update
documentation as well after this patch will be merged.
--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com
^ permalink raw reply
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