Merge tag 'tpmdd-next-6.15-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd

Pull tpm fixes from Jarkko Sakkinen:
 "A few last minute fixes for v6.15"

* tag 'tpmdd-next-6.15-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
  tpm: tis: Double the timeout B to 4s
  char: tpm: tpm-buf: Add sanity check fallback in read helpers
  tpm: Mask TPM RC in tpm2_start_auth_session()

4 files changed, 30 insertions, 19 deletions

diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index e49a19fea3bdf..dc882fc9fa9ef 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -201,7 +201,7 @@ static void tpm_buf_read(struct tpm_buf *buf, off_t *offset, size_t count, void
  */
 u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset)
 {
-	u8 value;
+	u8 value = 0;
 
 	tpm_buf_read(buf, offset, sizeof(value), &value);
 
@@ -218,7 +218,7 @@ EXPORT_SYMBOL_GPL(tpm_buf_read_u8);
  */
 u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset)
 {
-	u16 value;
+	u16 value = 0;
 
 	tpm_buf_read(buf, offset, sizeof(value), &value);
 
@@ -235,7 +235,7 @@ EXPORT_SYMBOL_GPL(tpm_buf_read_u16);
  */
 u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset)
 {
-	u32 value;
+	u32 value = 0;
 
 	tpm_buf_read(buf, offset, sizeof(value), &value);
 
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 3f89635ba5e85..7b5049b3d476e 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -40,11 +40,6 @@
  *
  * These are the usage functions:
  *
- * tpm2_start_auth_session() which allocates the opaque auth structure
- *	and gets a session from the TPM.  This must be called before
- *	any of the following functions.  The session is protected by a
- *	session_key which is derived from a random salt value
- *	encrypted to the NULL seed.
  * tpm2_end_auth_session() kills the session and frees the resources.
  *	Under normal operation this function is done by
  *	tpm_buf_check_hmac_response(), so this is only to be used on
@@ -963,16 +958,13 @@ err:
 }
 
 /**
- * tpm2_start_auth_session() - create a HMAC authentication session with the TPM
- * @chip: the TPM chip structure to create the session with
+ * tpm2_start_auth_session() - Create an a HMAC authentication session
+ * @chip:	A TPM chip
  *
- * This function loads the NULL seed from its saved context and starts
- * an authentication session on the null seed, fills in the
- * @chip->auth structure to contain all the session details necessary
- * for performing the HMAC, encrypt and decrypt operations and
- * returns.  The NULL seed is flushed before this function returns.
+ * Loads the ephemeral key (null seed), and starts an HMAC authenticated
+ * session. The null seed is flushed before the return.
  *
- * Return: zero on success or actual error encountered.
+ * Returns zero on success, or a POSIX error code.
  */
 int tpm2_start_auth_session(struct tpm_chip *chip)
 {
@@ -1024,7 +1016,7 @@ int tpm2_start_auth_session(struct tpm_chip *chip)
 	/* hash algorithm for session */
 	tpm_buf_append_u16(&buf, TPM_ALG_SHA256);
 
-	rc = tpm_transmit_cmd(chip, &buf, 0, "start auth session");
+	rc = tpm_ret_to_err(tpm_transmit_cmd(chip, &buf, 0, "StartAuthSession"));
 	tpm2_flush_context(chip, null_key);
 
 	if (rc == TPM2_RC_SUCCESS)
diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index 970d02c337c7f..6c3aa480396b6 100644
--- a/drivers/char/tpm/tpm_tis_core.h
+++ b/drivers/char/tpm/tpm_tis_core.h
@@ -54,7 +54,7 @@ enum tis_int_flags {
 enum tis_defaults {
 	TIS_MEM_LEN = 0x5000,
 	TIS_SHORT_TIMEOUT = 750,	/* ms */
-	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
+	TIS_LONG_TIMEOUT = 4000,	/* 4 secs */
 	TIS_TIMEOUT_MIN_ATML = 14700,	/* usecs */
 	TIS_TIMEOUT_MAX_ATML = 15000,	/* usecs */
 };
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 6c3125300c009..a3d8305e88a51 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -224,7 +224,7 @@ enum tpm2_const {
 
 enum tpm2_timeouts {
 	TPM2_TIMEOUT_A          =    750,
-	TPM2_TIMEOUT_B          =   2000,
+	TPM2_TIMEOUT_B          =   4000,
 	TPM2_TIMEOUT_C          =    200,
 	TPM2_TIMEOUT_D          =     30,
 	TPM2_DURATION_SHORT     =     20,
@@ -257,6 +257,7 @@ enum tpm2_return_codes {
 	TPM2_RC_TESTING		= 0x090A, /* RC_WARN */
 	TPM2_RC_REFERENCE_H0	= 0x0910,
 	TPM2_RC_RETRY		= 0x0922,
+	TPM2_RC_SESSION_MEMORY	= 0x0903,
 };
 
 enum tpm2_command_codes {
@@ -437,6 +438,24 @@ static inline u32 tpm2_rc_value(u32 rc)
 	return (rc & BIT(7)) ? rc & 0xbf : rc;
 }
 
+/*
+ * Convert a return value from tpm_transmit_cmd() to POSIX error code.
+ */
+static inline ssize_t tpm_ret_to_err(ssize_t ret)
+{
+	if (ret < 0)
+		return ret;
+
+	switch (tpm2_rc_value(ret)) {
+	case TPM2_RC_SUCCESS:
+		return 0;
+	case TPM2_RC_SESSION_MEMORY:
+		return -ENOMEM;
+	default:
+		return -EFAULT;
+	}
+}
+
 #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
 
 extern int tpm_is_tpm2(struct tpm_chip *chip);