[PATCH v4 0/4] tpm2-sessions: Fixes for v6.19-rc2

[PATCH v4 0/4] tpm2-sessions: Fixes for v6.19-rc2

[Jarkko Sakkinen]

I collected the accumulated fixed for tpm2-sessions, geared towards
v6.19-rc2.

v4:
- Removed spurious newline and renamed 'rc' as 'name_size_alg'.
- Return name size from tpm2_read_public() back to caller.
v3:
- Fixed two issues in 1/4.
v2:
- Addressed issues reported by Jonathan McDowell:
  https://lore.kernel.org/linux-integrity/aS8TIeviaippVAha@earth.li/

Jarkko Sakkinen (4):
  tpm2-sessions: Fix out of range indexing in name_size
  tpm2-sessions: Fix tpm2_read_public range checks
  tpm2-sessions: Remove 'attributes' parameter from tpm_buf_append_auth
  tpm2-sessions: Open code tpm_buf_append_hmac_session()

 drivers/char/tpm/tpm2-cmd.c               |  42 ++++-
 drivers/char/tpm/tpm2-sessions.c          | 199 ++++++++++++++--------
 include/linux/tpm.h                       |  38 +----
 security/keys/trusted-keys/trusted_tpm2.c |  41 ++++-
 4 files changed, 204 insertions(+), 116 deletions(-)

-- 
2.52.0

[PATCH v4 1/4] tpm2-sessions: Fix out of range indexing in name_size

[Jarkko Sakkinen]

'name_size' does not have any range checks, and it just directly indexes
with TPM_ALG_ID, which could lead into memory corruption at worst.

Address the issue by only processing known values and returning -EINVAL for
unrecognized values.

Make also 'tpm_buf_append_name' and 'tpm_buf_fill_hmac_session' fallible so
that errors are detected before causing any spurious TPM traffic.

End also the authorization session on failure in both of the functions, as
the session state would be then by definition corrupted.

Cc: stable@vger.kernel.org # v6.10+
Fixes: 1085b8276bb4 ("tpm: Add the rest of the session HMAC API")
Reviewed-by: Jonathan McDowell <noodles@meta.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v4:
- Removed spurious empty line.
v3:
- Fix pr_warn() format string in name_size().
- Fix !CONFIG_TPM2_HMAC compilation.
v2:
- Wrote a better short summary.
- Addressed remarks in https://lore.kernel.org/linux-integrity/aS8TIeviaippVAha@earth.li/
- Use -EIO consistently in tpm2_fill_hmac_session. These are not input value
  errors. They could only spun from malformed (kernel) state.
- name_size did not have a proper default-case. Reorganize the
  fallback into that.
---
 drivers/char/tpm/tpm2-cmd.c               |  23 +++-
 drivers/char/tpm/tpm2-sessions.c          | 132 +++++++++++++++-------
 include/linux/tpm.h                       |  13 ++-
 security/keys/trusted-keys/trusted_tpm2.c |  29 ++++-
 4 files changed, 142 insertions(+), 55 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index dd502322f499..be4a9c7f2e1a 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -199,7 +199,11 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 	}
 
 	if (!disable_pcr_integrity) {
-		tpm_buf_append_name(chip, &buf, pcr_idx, NULL);
+		rc = tpm_buf_append_name(chip, &buf, pcr_idx, NULL);
+		if (rc) {
+			tpm_buf_destroy(&buf);
+			return rc;
+		}
 		tpm_buf_append_hmac_session(chip, &buf, 0, NULL, 0);
 	} else {
 		tpm_buf_append_handle(chip, &buf, pcr_idx);
@@ -214,8 +218,14 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 			       chip->allocated_banks[i].digest_size);
 	}
 
-	if (!disable_pcr_integrity)
-		tpm_buf_fill_hmac_session(chip, &buf);
+	if (!disable_pcr_integrity) {
+		rc = tpm_buf_fill_hmac_session(chip, &buf);
+		if (rc) {
+			tpm_buf_destroy(&buf);
+			return rc;
+		}
+	}
+
 	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting extend a PCR value");
 	if (!disable_pcr_integrity)
 		rc = tpm_buf_check_hmac_response(chip, &buf, rc);
@@ -273,7 +283,12 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 						| TPM2_SA_CONTINUE_SESSION,
 						NULL, 0);
 		tpm_buf_append_u16(&buf, num_bytes);
-		tpm_buf_fill_hmac_session(chip, &buf);
+		err = tpm_buf_fill_hmac_session(chip, &buf);
+		if (err) {
+			tpm_buf_destroy(&buf);
+			return err;
+		}
+
 		err = tpm_transmit_cmd(chip, &buf,
 				       offsetof(struct tpm2_get_random_out,
 						buffer),
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 6d03c224e6b2..385014dbca39 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -144,16 +144,23 @@ struct tpm2_auth {
 /*
  * Name Size based on TPM algorithm (assumes no hash bigger than 255)
  */
-static u8 name_size(const u8 *name)
+static int name_size(const u8 *name)
 {
-	static u8 size_map[] = {
-		[TPM_ALG_SHA1] = SHA1_DIGEST_SIZE,
-		[TPM_ALG_SHA256] = SHA256_DIGEST_SIZE,
-		[TPM_ALG_SHA384] = SHA384_DIGEST_SIZE,
-		[TPM_ALG_SHA512] = SHA512_DIGEST_SIZE,
-	};
-	u16 alg = get_unaligned_be16(name);
-	return size_map[alg] + 2;
+	u16 hash_alg = get_unaligned_be16(name);
+
+	switch (hash_alg) {
+	case TPM_ALG_SHA1:
+		return SHA1_DIGEST_SIZE + 2;
+	case TPM_ALG_SHA256:
+		return SHA256_DIGEST_SIZE + 2;
+	case TPM_ALG_SHA384:
+		return SHA384_DIGEST_SIZE + 2;
+	case TPM_ALG_SHA512:
+		return SHA512_DIGEST_SIZE + 2;
+	default:
+		pr_warn("tpm: unsupported name algorithm: 0x%04x\n", hash_alg);
+		return -EINVAL;
+	}
 }
 
 static int tpm2_parse_read_public(char *name, struct tpm_buf *buf)
@@ -161,6 +168,7 @@ static int tpm2_parse_read_public(char *name, struct tpm_buf *buf)
 	struct tpm_header *head = (struct tpm_header *)buf->data;
 	off_t offset = TPM_HEADER_SIZE;
 	u32 tot_len = be32_to_cpu(head->length);
+	int ret;
 	u32 val;
 
 	/* we're starting after the header so adjust the length */
@@ -173,8 +181,13 @@ static int tpm2_parse_read_public(char *name, struct tpm_buf *buf)
 	offset += val;
 	/* name */
 	val = tpm_buf_read_u16(buf, &offset);
-	if (val != name_size(&buf->data[offset]))
+	ret = name_size(&buf->data[offset]);
+	if (ret < 0)
+		return ret;
+
+	if (val != ret)
 		return -EINVAL;
+
 	memcpy(name, &buf->data[offset], val);
 	/* forget the rest */
 	return 0;
@@ -221,46 +234,72 @@ static int tpm2_read_public(struct tpm_chip *chip, u32 handle, char *name)
  * As with most tpm_buf operations, success is assumed because failure
  * will be caused by an incorrect programming model and indicated by a
  * kernel message.
+ *
+ * Ends the authorization session on failure.
  */
-void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
-			 u32 handle, u8 *name)
+int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
+			u32 handle, u8 *name)
 {
 #ifdef CONFIG_TCG_TPM2_HMAC
 	enum tpm2_mso_type mso = tpm2_handle_mso(handle);
 	struct tpm2_auth *auth;
 	int slot;
+	int ret;
 #endif
 
 	if (!tpm2_chip_auth(chip)) {
 		tpm_buf_append_handle(chip, buf, handle);
-		return;
+		return 0;
 	}
 
 #ifdef CONFIG_TCG_TPM2_HMAC
 	slot = (tpm_buf_length(buf) - TPM_HEADER_SIZE) / 4;
 	if (slot >= AUTH_MAX_NAMES) {
-		dev_err(&chip->dev, "TPM: too many handles\n");
-		return;
+		dev_err(&chip->dev, "too many handles\n");
+		ret = -EIO;
+		goto err;
 	}
 	auth = chip->auth;
-	WARN(auth->session != tpm_buf_length(buf),
-	     "name added in wrong place\n");
+	if (auth->session != tpm_buf_length(buf)) {
+		dev_err(&chip->dev, "session state malformed");
+		ret = -EIO;
+		goto err;
+	}
 	tpm_buf_append_u32(buf, handle);
 	auth->session += 4;
 
 	if (mso == TPM2_MSO_PERSISTENT ||
 	    mso == TPM2_MSO_VOLATILE ||
 	    mso == TPM2_MSO_NVRAM) {
-		if (!name)
-			tpm2_read_public(chip, handle, auth->name[slot]);
+		if (!name) {
+			ret = tpm2_read_public(chip, handle, auth->name[slot]);
+			if (ret)
+				goto err;
+		}
 	} else {
-		if (name)
-			dev_err(&chip->dev, "TPM: Handle does not require name but one is specified\n");
+		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(name));
+	if (name) {
+		ret = name_size(name);
+		if (ret < 0)
+			goto err;
+
+		memcpy(auth->name[slot], name, ret);
+	}
+#endif
+	return 0;
+
+#ifdef CONFIG_TCG_TPM2_HMAC
+err:
+	tpm2_end_auth_session(chip);
+	return tpm_ret_to_err(ret);
 #endif
 }
 EXPORT_SYMBOL_GPL(tpm_buf_append_name);
@@ -533,11 +572,9 @@ static void tpm_buf_append_salt(struct tpm_buf *buf, struct tpm_chip *chip,
  * encryption key and encrypts the first parameter of the command
  * buffer with it.
  *
- * As with most tpm_buf operations, success is assumed because failure
- * will be caused by an incorrect programming model and indicated by a
- * kernel message.
+ * Ends the authorization session on failure.
  */
-void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
+int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 {
 	u32 cc, handles, val;
 	struct tpm2_auth *auth = chip->auth;
@@ -549,9 +586,12 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 	u8 cphash[SHA256_DIGEST_SIZE];
 	struct sha256_ctx sctx;
 	struct hmac_sha256_ctx hctx;
+	int ret;
 
-	if (!auth)
-		return;
+	if (!auth) {
+		ret = -EIO;
+		goto err;
+	}
 
 	/* save the command code in BE format */
 	auth->ordinal = head->ordinal;
@@ -560,9 +600,11 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 
 	i = tpm2_find_cc(chip, cc);
 	if (i < 0) {
-		dev_err(&chip->dev, "Command 0x%x not found in TPM\n", cc);
-		return;
+		dev_err(&chip->dev, "command 0x%08x not found\n", cc);
+		ret = -EIO;
+		goto err;
 	}
+
 	attrs = chip->cc_attrs_tbl[i];
 
 	handles = (attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0);
@@ -576,9 +618,9 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 		u32 handle = tpm_buf_read_u32(buf, &offset_s);
 
 		if (auth->name_h[i] != handle) {
-			dev_err(&chip->dev, "TPM: handle %d wrong for name\n",
-				  i);
-			return;
+			dev_err(&chip->dev, "invalid handle 0x%08x\n", handle);
+			ret = -EIO;
+			goto err;
 		}
 	}
 	/* point offset_s to the start of the sessions */
@@ -609,12 +651,14 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 		offset_s += len;
 	}
 	if (offset_s != offset_p) {
-		dev_err(&chip->dev, "TPM session length is incorrect\n");
-		return;
+		dev_err(&chip->dev, "session length is incorrect\n");
+		ret = -EIO;
+		goto err;
 	}
 	if (!hmac) {
-		dev_err(&chip->dev, "TPM could not find HMAC session\n");
-		return;
+		dev_err(&chip->dev, "could not find HMAC session\n");
+		ret = -EIO;
+		goto err;
 	}
 
 	/* encrypt before HMAC */
@@ -646,8 +690,11 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 		if (mso == TPM2_MSO_PERSISTENT ||
 		    mso == TPM2_MSO_VOLATILE ||
 		    mso == TPM2_MSO_NVRAM) {
-			sha256_update(&sctx, auth->name[i],
-				      name_size(auth->name[i]));
+			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]);
 
@@ -668,6 +715,11 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 	hmac_sha256_update(&hctx, auth->tpm_nonce, sizeof(auth->tpm_nonce));
 	hmac_sha256_update(&hctx, &auth->attrs, 1);
 	hmac_sha256_final(&hctx, hmac);
+	return 0;
+
+err:
+	tpm2_end_auth_session(chip);
+	return ret;
 }
 EXPORT_SYMBOL(tpm_buf_fill_hmac_session);
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 3d8f7d1ce2b8..aa816b144ab3 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -529,8 +529,8 @@ static inline struct tpm2_auth *tpm2_chip_auth(struct tpm_chip *chip)
 #endif
 }
 
-void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
-			 u32 handle, u8 *name);
+int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
+			u32 handle, u8 *name);
 void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf,
 				 u8 attributes, u8 *passphrase,
 				 int passphraselen);
@@ -563,7 +563,7 @@ static inline void tpm_buf_append_hmac_session_opt(struct tpm_chip *chip,
 #ifdef CONFIG_TCG_TPM2_HMAC
 
 int tpm2_start_auth_session(struct tpm_chip *chip);
-void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf);
+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);
@@ -577,10 +577,13 @@ static inline int tpm2_start_auth_session(struct tpm_chip *chip)
 static inline void tpm2_end_auth_session(struct tpm_chip *chip)
 {
 }
-static inline void tpm_buf_fill_hmac_session(struct tpm_chip *chip,
-					     struct tpm_buf *buf)
+
+static inline int tpm_buf_fill_hmac_session(struct tpm_chip *chip,
+					    struct tpm_buf *buf)
 {
+	return 0;
 }
+
 static inline int tpm_buf_check_hmac_response(struct tpm_chip *chip,
 					      struct tpm_buf *buf,
 					      int rc)
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 8bc6efa8accb..5b205279584b 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -268,7 +268,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		goto out_put;
 	}
 
-	tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	if (rc)
+		goto out;
+
 	tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT,
 				    options->keyauth, TPM_DIGEST_SIZE);
 
@@ -316,7 +319,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		goto out;
 	}
 
-	tpm_buf_fill_hmac_session(chip, &buf);
+	rc = tpm_buf_fill_hmac_session(chip, &buf);
+	if (rc)
+		goto out;
+
 	rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
 	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
 	if (rc)
@@ -427,7 +433,10 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 		return rc;
 	}
 
-	tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	if (rc)
+		goto out;
+
 	tpm_buf_append_hmac_session(chip, &buf, 0, options->keyauth,
 				    TPM_DIGEST_SIZE);
 
@@ -439,7 +448,10 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 		goto out;
 	}
 
-	tpm_buf_fill_hmac_session(chip, &buf);
+	rc = tpm_buf_fill_hmac_session(chip, &buf);
+	if (rc)
+		goto out;
+
 	rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
 	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
 	if (!rc)
@@ -484,7 +496,9 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 		return rc;
 	}
 
-	tpm_buf_append_name(chip, &buf, blob_handle, NULL);
+	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	if (rc)
+		goto out;
 
 	if (!options->policyhandle) {
 		tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT,
@@ -509,7 +523,10 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 						NULL, 0);
 	}
 
-	tpm_buf_fill_hmac_session(chip, &buf);
+	rc = tpm_buf_fill_hmac_session(chip, &buf);
+	if (rc)
+		goto out;
+
 	rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
 	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
 
-- 
2.52.0

[PATCH v4 2/4] tpm2-sessions: Fix tpm2_read_public range checks

[Jarkko Sakkinen]

tpm2_read_public() has some rudimentary range checks but the function does
not ensure that the response buffer has enough bytes for the full TPMT_HA
payload.

Re-implement the function with necessary checks and validation, and return
name and name size for all handle types back to the caller.

Cc: stable@vger.kernel.org # v6.10+
Fixes: d0a25bb961e6 ("tpm: Add HMAC session name/handle append")
Reviewed-by: Jonathan McDowell <noodles@meta.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v3:
- Rename 'rc2' as 'name_size_alg'.
- It makes a lot of sense to add additional robustness in name handling
  to tpm2_read_public. Thus also process handles whose handle name is
  the handle itself, and return name size back to the caller.
v3:
- No changes.
v2:
- Made the fix localized instead of spread all over the place.
---
 drivers/char/tpm/tpm2-cmd.c      |  3 +
 drivers/char/tpm/tpm2-sessions.c | 94 +++++++++++++++++---------------
 2 files changed, 53 insertions(+), 44 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index be4a9c7f2e1a..34e3599f094f 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -11,8 +11,11 @@
  * used by the kernel internally.
  */
 
+#include "linux/dev_printk.h"
+#include "linux/tpm.h"
 #include "tpm.h"
 #include <crypto/hash_info.h>
+#include <linux/unaligned.h>
 
 static bool disable_pcr_integrity;
 module_param(disable_pcr_integrity, bool, 0444);
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 385014dbca39..3f389e2f6f58 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -163,53 +163,61 @@ static int name_size(const u8 *name)
 	}
 }
 
-static int tpm2_parse_read_public(char *name, struct tpm_buf *buf)
+static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
 {
-	struct tpm_header *head = (struct tpm_header *)buf->data;
+	u32 mso = tpm2_handle_mso(handle);
 	off_t offset = TPM_HEADER_SIZE;
-	u32 tot_len = be32_to_cpu(head->length);
-	int ret;
-	u32 val;
-
-	/* we're starting after the header so adjust the length */
-	tot_len -= TPM_HEADER_SIZE;
-
-	/* skip public */
-	val = tpm_buf_read_u16(buf, &offset);
-	if (val > tot_len)
-		return -EINVAL;
-	offset += val;
-	/* name */
-	val = tpm_buf_read_u16(buf, &offset);
-	ret = name_size(&buf->data[offset]);
-	if (ret < 0)
-		return ret;
-
-	if (val != ret)
-		return -EINVAL;
-
-	memcpy(name, &buf->data[offset], val);
-	/* forget the rest */
-	return 0;
-}
-
-static int tpm2_read_public(struct tpm_chip *chip, u32 handle, char *name)
-{
+	int rc, name_size_alg;
 	struct tpm_buf buf;
-	int rc;
+
+	if (mso != TPM2_MSO_PERSISTENT && mso != TPM2_MSO_VOLATILE &&
+	    mso != TPM2_MSO_NVRAM) {
+		memcpy(name, &handle, sizeof(u32));
+		return sizeof(u32);
+	}
 
 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_READ_PUBLIC);
 	if (rc)
 		return rc;
 
 	tpm_buf_append_u32(&buf, handle);
-	rc = tpm_transmit_cmd(chip, &buf, 0, "read public");
-	if (rc == TPM2_RC_SUCCESS)
-		rc = tpm2_parse_read_public(name, &buf);
 
-	tpm_buf_destroy(&buf);
+	rc = tpm_transmit_cmd(chip, &buf, 0, "TPM2_ReadPublic");
+	if (rc) {
+		tpm_buf_destroy(&buf);
+		return tpm_ret_to_err(rc);
+	}
 
-	return rc;
+	/* Skip TPMT_PUBLIC: */
+	offset += tpm_buf_read_u16(&buf, &offset);
+
+	/*
+	 * Ensure space for the length field of TPM2B_NAME and hashAlg field of
+	 * TPMT_HA (the extra four bytes).
+	 */
+	if (offset + 4 > tpm_buf_length(&buf)) {
+		tpm_buf_destroy(&buf);
+		return -EIO;
+	}
+
+	rc = tpm_buf_read_u16(&buf, &offset);
+	name_size_alg = name_size(&buf.data[offset]);
+
+	if (name_size_alg < 0)
+		return name_size_alg;
+
+	if (rc != name_size_alg) {
+		tpm_buf_destroy(&buf);
+		return -EIO;
+	}
+
+	if (offset + rc > tpm_buf_length(&buf)) {
+		tpm_buf_destroy(&buf);
+		return -EIO;
+	}
+
+	memcpy(name, &buf.data[offset], rc);
+	return name_size_alg;
 }
 #endif /* CONFIG_TCG_TPM2_HMAC */
 
@@ -243,6 +251,7 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
 #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
@@ -273,8 +282,10 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
 	    mso == TPM2_MSO_NVRAM) {
 		if (!name) {
 			ret = tpm2_read_public(chip, handle, auth->name[slot]);
-			if (ret)
+			if (ret < 0)
 				goto err;
+
+			name_size_alg = ret;
 		}
 	} else {
 		if (name) {
@@ -286,13 +297,8 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
 	}
 
 	auth->name_h[slot] = handle;
-	if (name) {
-		ret = name_size(name);
-		if (ret < 0)
-			goto err;
-
-		memcpy(auth->name[slot], name, ret);
-	}
+	if (name)
+		memcpy(auth->name[slot], name, name_size_alg);
 #endif
 	return 0;
 
-- 
2.52.0

[PATCH v4 3/4] tpm2-sessions: Remove 'attributes' parameter from tpm_buf_append_auth

[Jarkko Sakkinen]

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

Remove 'attributes' parameter from 'tpm_buf_append_auth', as it is not used
by the function.

Fixes: 27184f8905ba ("tpm: Opt-in in disable PCR integrity protection")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>
Reviewed-by: Jonathan McDowell <noodles@meta.com>
---
 drivers/char/tpm/tpm2-cmd.c      | 2 +-
 drivers/char/tpm/tpm2-sessions.c | 5 ++---
 include/linux/tpm.h              | 2 +-
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 34e3599f094f..ce0a1c6b0596 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -210,7 +210,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 		tpm_buf_append_hmac_session(chip, &buf, 0, NULL, 0);
 	} else {
 		tpm_buf_append_handle(chip, &buf, pcr_idx);
-		tpm_buf_append_auth(chip, &buf, 0, NULL, 0);
+		tpm_buf_append_auth(chip, &buf, NULL, 0);
 	}
 
 	tpm_buf_append_u32(&buf, chip->nr_allocated_banks);
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 3f389e2f6f58..4149379665c4 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -311,7 +311,7 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
 EXPORT_SYMBOL_GPL(tpm_buf_append_name);
 
 void tpm_buf_append_auth(struct tpm_chip *chip, struct tpm_buf *buf,
-			 u8 attributes, u8 *passphrase, int passphrase_len)
+			 u8 *passphrase, int passphrase_len)
 {
 	/* offset tells us where the sessions area begins */
 	int offset = buf->handles * 4 + TPM_HEADER_SIZE;
@@ -372,8 +372,7 @@ void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf,
 #endif
 
 	if (!tpm2_chip_auth(chip)) {
-		tpm_buf_append_auth(chip, buf, attributes, passphrase,
-				    passphrase_len);
+		tpm_buf_append_auth(chip, buf, passphrase, passphrase_len);
 		return;
 	}
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index aa816b144ab3..afa51723296a 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -535,7 +535,7 @@ void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf,
 				 u8 attributes, u8 *passphrase,
 				 int passphraselen);
 void tpm_buf_append_auth(struct tpm_chip *chip, struct tpm_buf *buf,
-			 u8 attributes, u8 *passphrase, int passphraselen);
+			 u8 *passphrase, int passphraselen);
 static inline void tpm_buf_append_hmac_session_opt(struct tpm_chip *chip,
 						   struct tpm_buf *buf,
 						   u8 attributes,
-- 
2.52.0

[PATCH v4 4/4] tpm2-sessions: Open code tpm_buf_append_hmac_session()

[Jarkko Sakkinen]

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

Open code 'tpm_buf_append_hmac_session_opt' to the call site, as it only
masks a call sequence and does otherwise nothing particularly useful.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>
Reviewed-by: Jonathan McDowell <noodles@meta.com>
---
 drivers/char/tpm/tpm2-cmd.c               | 14 +++++++++++---
 include/linux/tpm.h                       | 23 -----------------------
 security/keys/trusted-keys/trusted_tpm2.c | 12 ++++++++++--
 3 files changed, 21 insertions(+), 28 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index ce0a1c6b0596..3a77be7ebf4a 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -282,9 +282,17 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 
 	do {
 		tpm_buf_reset(&buf, TPM2_ST_SESSIONS, TPM2_CC_GET_RANDOM);
-		tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT
-						| TPM2_SA_CONTINUE_SESSION,
-						NULL, 0);
+		if (tpm2_chip_auth(chip)) {
+			tpm_buf_append_hmac_session(chip, &buf,
+						    TPM2_SA_ENCRYPT |
+						    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);
+		}
 		tpm_buf_append_u16(&buf, num_bytes);
 		err = tpm_buf_fill_hmac_session(chip, &buf);
 		if (err) {
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index afa51723296a..202da079d500 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -536,29 +536,6 @@ void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf,
 				 int passphraselen);
 void tpm_buf_append_auth(struct tpm_chip *chip, struct tpm_buf *buf,
 			 u8 *passphrase, int passphraselen);
-static inline void tpm_buf_append_hmac_session_opt(struct tpm_chip *chip,
-						   struct tpm_buf *buf,
-						   u8 attributes,
-						   u8 *passphrase,
-						   int passphraselen)
-{
-	struct tpm_header *head;
-	int offset;
-
-	if (tpm2_chip_auth(chip)) {
-		tpm_buf_append_hmac_session(chip, buf, attributes, passphrase, passphraselen);
-	} else  {
-		offset = buf->handles * 4 + TPM_HEADER_SIZE;
-		head = (struct tpm_header *)buf->data;
-
-		/*
-		 * If the only sessions are optional, the command tag must change to
-		 * TPM2_ST_NO_SESSIONS.
-		 */
-		if (tpm_buf_length(buf) == offset)
-			head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
-	}
-}
 
 #ifdef CONFIG_TCG_TPM2_HMAC
 
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 5b205279584b..a7ea4a1c3bed 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -481,8 +481,10 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 			   struct trusted_key_options *options,
 			   u32 blob_handle)
 {
+	struct tpm_header *head;
 	struct tpm_buf buf;
 	u16 data_len;
+	int offset;
 	u8 *data;
 	int rc;
 
@@ -519,8 +521,14 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 		tpm2_buf_append_auth(&buf, options->policyhandle,
 				     NULL /* nonce */, 0, 0,
 				     options->blobauth, options->blobauth_len);
-		tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT,
-						NULL, 0);
+		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