[PATCH v4 0/5] Lazy flush for the auth session

[PATCH v4 0/5] Lazy flush for the auth session

[Jarkko Sakkinen]

For the sake of:
https://bugzilla.kernel.org/show_bug.cgi?id=219229

The baseline for the series is v6.11 tag.

v3: 
https://lore.kernel.org/linux-integrity/20240917154444.702370-1-jarkko@kernel.org/
v2:
https://lore.kernel.org/linux-integrity/20240916110714.1396407-1-jarkko@kernel.org/
v1:
https://lore.kernel.org/linux-integrity/20240915180448.2030115-1-jarkko@kernel.org/

Jarkko Sakkinen (5):
  tpm: Return on tpm2_create_null_primary() failure
  tpm: Return on tpm2_create_primary() failure in tpm2_load_null()
  tpm: flush the null key only when /dev/tpm0 is accessed
  tpm: Allocate chip->auth in tpm2_start_auth_session()
  tpm: flush the auth session only when /dev/tpm0 is open

 drivers/char/tpm/tpm-chip.c       |  14 ++++
 drivers/char/tpm/tpm-dev-common.c |   8 +++
 drivers/char/tpm/tpm-interface.c  |  10 ++-
 drivers/char/tpm/tpm2-cmd.c       |   3 +
 drivers/char/tpm/tpm2-sessions.c  | 109 +++++++++++++++++++-----------
 include/linux/tpm.h               |   2 +
 6 files changed, 104 insertions(+), 42 deletions(-)

-- 
2.46.0

[PATCH v4 1/5] tpm: Return on tpm2_create_null_primary() failure

[Jarkko Sakkinen]

tpm2_sessions_init() does not ignores the result of saving the null key.
Address this by printing either TPM or POSIX error code, and returning
-ENODEV back to the caller.

Cc: stable@vger.kernel.org # v6.10+
Fixes: d2add27cf2b8 ("tpm: Add NULL primary creation")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v4:
- Fixed up stable version.
v3:
- Handle TPM and POSIX error separately and return -ENODEV always back
  to the caller.
v2:
- Refined the commit message.
---
 drivers/char/tpm/tpm2-sessions.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index d3521aadd43e..795f4c7c6adb 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -1338,7 +1338,13 @@ static int tpm2_create_null_primary(struct tpm_chip *chip)
 		tpm2_flush_context(chip, null_key);
 	}
 
-	return rc;
+	if (rc < 0)
+		dev_err(&chip->dev, "saving the null key failed with error %d\n", rc);
+	else if (rc > 0)
+		dev_err(&chip->dev, "saving the null key failed with TPM error 0x%04X\n", rc);
+
+	/* Map all errors to -ENODEV: */
+	return rc ? -ENODEV : rc;
 }
 
 /**
@@ -1354,7 +1360,7 @@ int tpm2_sessions_init(struct tpm_chip *chip)
 
 	rc = tpm2_create_null_primary(chip);
 	if (rc)
-		dev_err(&chip->dev, "TPM: security failed (NULL seed derivation): %d\n", rc);
+		return rc;
 
 	chip->auth = kmalloc(sizeof(*chip->auth), GFP_KERNEL);
 	if (!chip->auth)
-- 
2.46.0

[PATCH v4 2/5] tpm: Return on tpm2_create_primary() failure in tpm2_load_null()

[Jarkko Sakkinen]

tpm2_load_null() ignores the return value of tpm2_create_primary().
Further, it does not heal from the situation when memcmp() returns zero.

Address this by returning on failure and saving the null key if there
was no detected interference in the bus.

Cc: stable@vger.kernel.org # v6.10+
Fixes: eb24c9788cd9 ("tpm: disable the TPM if NULL name changes")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v3:
- Update log messages. Previously the log message incorrectly stated
  on load failure that integrity check had been failed, even tho the
  check is done *after* the load operation.
v2:
- Refined the commit message.
- Reverted tpm2_create_primary() changes. They are not required if
  tmp_null_key is used as the parameter.
---
 drivers/char/tpm/tpm2-sessions.c | 38 +++++++++++++++++---------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 795f4c7c6adb..a62f64e21511 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -915,32 +915,34 @@ static int tpm2_parse_start_auth_session(struct tpm2_auth *auth,
 
 static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key)
 {
-	int rc;
 	unsigned int offset = 0; /* dummy offset for null seed context */
 	u8 name[SHA256_DIGEST_SIZE + 2];
+	u32 tmp_null_key;
+	int rc;
 
 	rc = tpm2_load_context(chip, chip->null_key_context, &offset,
-			       null_key);
-	if (rc != -EINVAL)
+			       &tmp_null_key);
+	if (rc != -EINVAL) {
+		if (!rc)
+			*null_key = tmp_null_key;
 		return rc;
+	}
+	dev_info(&chip->dev, "the null key has been reset\n");
 
-	/* an integrity failure may mean the TPM has been reset */
-	dev_err(&chip->dev, "NULL key integrity failure!\n");
-	/* check the null name against what we know */
-	tpm2_create_primary(chip, TPM2_RH_NULL, NULL, name);
-	if (memcmp(name, chip->null_key_name, sizeof(name)) == 0)
-		/* name unchanged, assume transient integrity failure */
+	rc = tpm2_create_primary(chip, TPM2_RH_NULL, &tmp_null_key, name);
+	if (rc)
 		return rc;
-	/*
-	 * Fatal TPM failure: the NULL seed has actually changed, so
-	 * the TPM must have been illegally reset.  All in-kernel TPM
-	 * operations will fail because the NULL primary can't be
-	 * loaded to salt the sessions, but disable the TPM anyway so
-	 * userspace programmes can't be compromised by it.
-	 */
-	dev_err(&chip->dev, "NULL name has changed, disabling TPM due to interference\n");
-	chip->flags |= TPM_CHIP_FLAG_DISABLE;
 
+	/* Return the null key if the name has not been changed: */
+	if (memcmp(name, chip->null_key_name, sizeof(name)) == 0) {
+		*null_key = tmp_null_key;
+		return 0;
+	}
+
+	/* Deduce from the name change TPM interference: */
+	dev_err(&chip->dev, "the null key integrity check failedh\n");
+	tpm2_flush_context(chip, tmp_null_key);
+	chip->flags |= TPM_CHIP_FLAG_DISABLE;
 	return rc;
 }
 
-- 
2.46.0

[PATCH v4 3/5] tpm: flush the null key only when /dev/tpm0 is accessed

[Jarkko Sakkinen]

Instead of flushing and reloading the null key for every single auth
session, flush it only when:

1. User space needs to access /dev/tpm{rm}0.
2. When going to sleep.
3. When unregistering the chip.

This removes the need to load and swap the null key between TPM and
regular memory per transaction, when the user space is not using the
chip.

Cc: stable@vger.kernel.org # v6.10+
Fixes: d2add27cf2b8 ("tpm: Add NULL primary creation")
Tested-by: Pengyu Ma <mapengyu@gmail.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v4:
- Changed to bug fix as not having the patch there is a major hit
  to bootup times.
v3:
- Unchanged.
v2:
- Refined the commit message.
- Added tested-by from Pengyu Ma <mapengyu@gmail.com>.
- Removed spurious pr_info() statement.
---
 drivers/char/tpm/tpm-chip.c       | 13 +++++++++++++
 drivers/char/tpm/tpm-dev-common.c |  7 +++++++
 drivers/char/tpm/tpm-interface.c  |  9 +++++++--
 drivers/char/tpm/tpm2-cmd.c       |  3 +++
 drivers/char/tpm/tpm2-sessions.c  | 17 ++++++++++++++---
 include/linux/tpm.h               |  2 ++
 6 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 854546000c92..0ea00e32f575 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -674,6 +674,19 @@ EXPORT_SYMBOL_GPL(tpm_chip_register);
  */
 void tpm_chip_unregister(struct tpm_chip *chip)
 {
+#ifdef CONFIG_TCG_TPM2_HMAC
+	int rc;
+
+	rc = tpm_try_get_ops(chip);
+	if (!rc) {
+		if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+			tpm2_flush_context(chip, chip->null_key);
+			chip->null_key = 0;
+		}
+		tpm_put_ops(chip);
+	}
+#endif
+
 	tpm_del_legacy_sysfs(chip);
 	if (tpm_is_hwrng_enabled(chip))
 		hwrng_unregister(&chip->hwrng);
diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 30b4c288c1bb..4eaa8e05c291 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -27,6 +27,13 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	struct tpm_header *header = (void *)buf;
 	ssize_t ret, len;
 
+#ifdef CONFIG_TCG_TPM2_HMAC
+	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+		tpm2_flush_context(chip, chip->null_key);
+		chip->null_key = 0;
+	}
+#endif
+
 	ret = tpm2_prepare_space(chip, space, buf, bufsiz);
 	/* If the command is not implemented by the TPM, synthesize a
 	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5da134f12c9a..bfa47d48b0f2 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -379,10 +379,15 @@ int tpm_pm_suspend(struct device *dev)
 
 	rc = tpm_try_get_ops(chip);
 	if (!rc) {
-		if (chip->flags & TPM_CHIP_FLAG_TPM2)
+		if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+#ifdef CONFIG_TCG_TPM2_HMAC
+			tpm2_flush_context(chip, chip->null_key);
+			chip->null_key = 0;
+#endif
 			tpm2_shutdown(chip, TPM2_SU_STATE);
-		else
+		} else {
 			rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);
+		}
 
 		tpm_put_ops(chip);
 	}
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 1e856259219e..aba024cbe7c5 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -364,6 +364,9 @@ void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
 	struct tpm_buf buf;
 	int rc;
 
+	if (!handle)
+		return;
+
 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT);
 	if (rc) {
 		dev_warn(&chip->dev, "0x%08x was not flushed, out of memory\n",
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index a62f64e21511..42eb910e9acc 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -920,11 +920,19 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key)
 	u32 tmp_null_key;
 	int rc;
 
+	/* fast path */
+	if (chip->null_key) {
+		*null_key = chip->null_key;
+		return 0;
+	}
+
 	rc = tpm2_load_context(chip, chip->null_key_context, &offset,
 			       &tmp_null_key);
 	if (rc != -EINVAL) {
-		if (!rc)
+		if (!rc) {
+			chip->null_key = tmp_null_key;
 			*null_key = tmp_null_key;
+		}
 		return rc;
 	}
 	dev_info(&chip->dev, "the null key has been reset\n");
@@ -935,6 +943,7 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key)
 
 	/* Return the null key if the name has not been changed: */
 	if (memcmp(name, chip->null_key_name, sizeof(name)) == 0) {
+		chip->null_key = tmp_null_key;
 		*null_key = tmp_null_key;
 		return 0;
 	}
@@ -1005,7 +1014,6 @@ int tpm2_start_auth_session(struct tpm_chip *chip)
 	tpm_buf_append_u16(&buf, TPM_ALG_SHA256);
 
 	rc = tpm_transmit_cmd(chip, &buf, 0, "start auth session");
-	tpm2_flush_context(chip, null_key);
 
 	if (rc == TPM2_RC_SUCCESS)
 		rc = tpm2_parse_start_auth_session(auth, &buf);
@@ -1337,7 +1345,10 @@ static int tpm2_create_null_primary(struct tpm_chip *chip)
 
 		rc = tpm2_save_context(chip, null_key, chip->null_key_context,
 				       sizeof(chip->null_key_context), &offset);
-		tpm2_flush_context(chip, null_key);
+		if (rc)
+			tpm2_flush_context(chip, null_key);
+		else
+			chip->null_key = null_key;
 	}
 
 	if (rc < 0)
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index e93ee8d936a9..4eb39db80e05 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -205,6 +205,8 @@ struct tpm_chip {
 #ifdef CONFIG_TCG_TPM2_HMAC
 	/* details for communication security via sessions */
 
+	/* loaded null key */
+	u32 null_key;
 	/* saved context for NULL seed */
 	u8 null_key_context[TPM2_MAX_CONTEXT_SIZE];
 	 /* name of NULL seed */
-- 
2.46.0

[PATCH v4 4/5] tpm: Allocate chip->auth in tpm2_start_auth_session()

[Jarkko Sakkinen]

Move allocation of chip->auth to tpm2_start_auth_session() so that the
field can be used as flag to tell whether auth session is active or not.

Cc: stable@vger.kernel.org # v6.10+
Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v4:
- Change to bug.
v3:
- No changes.
v2:
- A new patch.
---
 drivers/char/tpm/tpm2-sessions.c | 43 +++++++++++++++++++-------------
 1 file changed, 25 insertions(+), 18 deletions(-)

diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 42eb910e9acc..6371e0ee88b0 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -484,7 +484,8 @@ static void tpm2_KDFe(u8 z[EC_PT_SZ], const char *str, u8 *pt_u, u8 *pt_v,
 	sha256_final(&sctx, out);
 }
 
-static void tpm_buf_append_salt(struct tpm_buf *buf, struct tpm_chip *chip)
+static void tpm_buf_append_salt(struct tpm_buf *buf, struct tpm_chip *chip,
+				struct tpm2_auth *auth)
 {
 	struct crypto_kpp *kpp;
 	struct kpp_request *req;
@@ -543,7 +544,7 @@ static void tpm_buf_append_salt(struct tpm_buf *buf, struct tpm_chip *chip)
 	sg_set_buf(&s[0], chip->null_ec_key_x, EC_PT_SZ);
 	sg_set_buf(&s[1], chip->null_ec_key_y, EC_PT_SZ);
 	kpp_request_set_input(req, s, EC_PT_SZ*2);
-	sg_init_one(d, chip->auth->salt, EC_PT_SZ);
+	sg_init_one(d, auth->salt, EC_PT_SZ);
 	kpp_request_set_output(req, d, EC_PT_SZ);
 	crypto_kpp_compute_shared_secret(req);
 	kpp_request_free(req);
@@ -554,8 +555,7 @@ static void tpm_buf_append_salt(struct tpm_buf *buf, struct tpm_chip *chip)
 	 * This works because KDFe fully consumes the secret before it
 	 * writes the salt
 	 */
-	tpm2_KDFe(chip->auth->salt, "SECRET", x, chip->null_ec_key_x,
-		  chip->auth->salt);
+	tpm2_KDFe(auth->salt, "SECRET", x, chip->null_ec_key_x, auth->salt);
 
  out:
 	crypto_free_kpp(kpp);
@@ -854,6 +854,8 @@ int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf,
 			/* manually close the session if it wasn't consumed */
 			tpm2_flush_context(chip, auth->handle);
 		memzero_explicit(auth, sizeof(*auth));
+		kfree(auth);
+		chip->auth = NULL;
 	} else {
 		/* reset for next use  */
 		auth->session = TPM_HEADER_SIZE;
@@ -882,6 +884,8 @@ void tpm2_end_auth_session(struct tpm_chip *chip)
 
 	tpm2_flush_context(chip, auth->handle);
 	memzero_explicit(auth, sizeof(*auth));
+	kfree(auth);
+	chip->auth = NULL;
 }
 EXPORT_SYMBOL(tpm2_end_auth_session);
 
@@ -969,25 +973,29 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key)
  */
 int tpm2_start_auth_session(struct tpm_chip *chip)
 {
+	struct tpm2_auth *auth;
 	struct tpm_buf buf;
-	struct tpm2_auth *auth = chip->auth;
-	int rc;
 	u32 null_key;
+	int rc;
 
-	if (!auth) {
-		dev_warn_once(&chip->dev, "auth session is not active\n");
+	if (chip->auth) {
+		dev_warn_once(&chip->dev, "auth session is active\n");
 		return 0;
 	}
 
+	auth = kzalloc(sizeof(*auth), GFP_KERNEL);
+	if (!auth)
+		return -ENOMEM;
+
 	rc = tpm2_load_null(chip, &null_key);
 	if (rc)
-		goto out;
+		goto err;
 
 	auth->session = TPM_HEADER_SIZE;
 
 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_START_AUTH_SESS);
 	if (rc)
-		goto out;
+		goto err;
 
 	/* salt key handle */
 	tpm_buf_append_u32(&buf, null_key);
@@ -999,7 +1007,7 @@ int tpm2_start_auth_session(struct tpm_chip *chip)
 	tpm_buf_append(&buf, auth->our_nonce, sizeof(auth->our_nonce));
 
 	/* append encrypted salt and squirrel away unencrypted in auth */
-	tpm_buf_append_salt(&buf, chip);
+	tpm_buf_append_salt(&buf, chip, auth);
 	/* session type (HMAC, audit or policy) */
 	tpm_buf_append_u8(&buf, TPM2_SE_HMAC);
 
@@ -1020,10 +1028,13 @@ int tpm2_start_auth_session(struct tpm_chip *chip)
 
 	tpm_buf_destroy(&buf);
 
-	if (rc)
-		goto out;
+	if (rc == TPM2_RC_SUCCESS) {
+		chip->auth = auth;
+		return 0;
+	}
 
- out:
+err:
+	kfree(auth);
 	return rc;
 }
 EXPORT_SYMBOL(tpm2_start_auth_session);
@@ -1375,10 +1386,6 @@ int tpm2_sessions_init(struct tpm_chip *chip)
 	if (rc)
 		return rc;
 
-	chip->auth = kmalloc(sizeof(*chip->auth), GFP_KERNEL);
-	if (!chip->auth)
-		return -ENOMEM;
-
 	return rc;
 }
 #endif /* CONFIG_TCG_TPM2_HMAC */
-- 
2.46.0

[PATCH v4 5/5] tpm: flush the auth session only when /dev/tpm0 is open

[Jarkko Sakkinen]

Instead of flushing and reloading the auth session for every single
transaction, keep the session open unless /dev/tpm0 is used. In practice
this means applying TPM2_SA_CONTINUE_SESSION to the session attributes.
Flush the session always when /dev/tpm0 is written.

Reported-by: Pengyu Ma <mapengyu@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219229
Cc: stable@vger.kernel.org # v6.10+
Fixes: 7ca110f2679b ("tpm: Address !chip->auth in tpm_buf_append_hmac_session*()")
Tested-by: Pengyu Ma <mapengyu@gmail.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v4:
- Changed as bug.
v3:
- Refined the commit message.
- Removed the conditional for applying TPM2_SA_CONTINUE_SESSION only when
  /dev/tpm0 is open. It is not required as the auth session is flushed,
  not saved.
v2:
- A new patch.
---
 drivers/char/tpm/tpm-chip.c       | 1 +
 drivers/char/tpm/tpm-dev-common.c | 1 +
 drivers/char/tpm/tpm-interface.c  | 1 +
 drivers/char/tpm/tpm2-sessions.c  | 3 +++
 4 files changed, 6 insertions(+)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 0ea00e32f575..7a6bb30d1f32 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -680,6 +680,7 @@ void tpm_chip_unregister(struct tpm_chip *chip)
 	rc = tpm_try_get_ops(chip);
 	if (!rc) {
 		if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+			tpm2_end_auth_session(chip);
 			tpm2_flush_context(chip, chip->null_key);
 			chip->null_key = 0;
 		}
diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 4eaa8e05c291..a3ed7a99a394 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -29,6 +29,7 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
 
 #ifdef CONFIG_TCG_TPM2_HMAC
 	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+		tpm2_end_auth_session(chip);
 		tpm2_flush_context(chip, chip->null_key);
 		chip->null_key = 0;
 	}
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index bfa47d48b0f2..2363018fa8fb 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -381,6 +381,7 @@ int tpm_pm_suspend(struct device *dev)
 	if (!rc) {
 		if (chip->flags & TPM_CHIP_FLAG_TPM2) {
 #ifdef CONFIG_TCG_TPM2_HMAC
+			tpm2_end_auth_session(chip);
 			tpm2_flush_context(chip, chip->null_key);
 			chip->null_key = 0;
 #endif
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 6371e0ee88b0..e9d3a6a9d397 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -333,6 +333,9 @@ void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf,
 	}
 
 #ifdef CONFIG_TCG_TPM2_HMAC
+	/* The first write to /dev/tpm{rm0} will flush the session. */
+	attributes |= TPM2_SA_CONTINUE_SESSION;
+
 	/*
 	 * The Architecture Guide requires us to strip trailing zeros
 	 * before computing the HMAC
-- 
2.46.0

Re: [PATCH v4 0/5] Lazy flush for the auth session

[Pengyu Ma]

On Thu, Sep 19, 2024 at 4:36 AM Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> For the sake of:
> https://bugzilla.kernel.org/show_bug.cgi?id=219229
>
> The baseline for the series is v6.11 tag.

Clean applied on v6.11 upstream kernel.
Boot time is 8.7 seconds which is almost good as 7 seconds without TPM2_HMAC.

Thanks,
Pengyu

>
> v3:
> https://lore.kernel.org/linux-integrity/20240917154444.702370-1-jarkko@kernel.org/
> v2:
> https://lore.kernel.org/linux-integrity/20240916110714.1396407-1-jarkko@kernel.org/
> v1:
> https://lore.kernel.org/linux-integrity/20240915180448.2030115-1-jarkko@kernel.org/
>
> Jarkko Sakkinen (5):
>   tpm: Return on tpm2_create_null_primary() failure
>   tpm: Return on tpm2_create_primary() failure in tpm2_load_null()
>   tpm: flush the null key only when /dev/tpm0 is accessed
>   tpm: Allocate chip->auth in tpm2_start_auth_session()
>   tpm: flush the auth session only when /dev/tpm0 is open
>
>  drivers/char/tpm/tpm-chip.c       |  14 ++++
>  drivers/char/tpm/tpm-dev-common.c |   8 +++
>  drivers/char/tpm/tpm-interface.c  |  10 ++-
>  drivers/char/tpm/tpm2-cmd.c       |   3 +
>  drivers/char/tpm/tpm2-sessions.c  | 109 +++++++++++++++++++-----------
>  include/linux/tpm.h               |   2 +
>  6 files changed, 104 insertions(+), 42 deletions(-)
>
> --
> 2.46.0
>

Re: [PATCH v4 0/5] Lazy flush for the auth session

[Jarkko Sakkinen]

On Thu Sep 19, 2024 at 4:12 AM EEST, Pengyu Ma wrote:
> On Thu, Sep 19, 2024 at 4:36 AM Jarkko Sakkinen <jarkko@kernel.org> wrote:
> >
> > For the sake of:
> > https://bugzilla.kernel.org/show_bug.cgi?id=219229
> >
> > The baseline for the series is v6.11 tag.
>
> Clean applied on v6.11 upstream kernel.
> Boot time is 8.7 seconds which is almost good as 7 seconds without TPM2_HMAC.

Awesome thank you! I think there could be some places where we could
further make "100 ms here and 50 ms there" time savings. I'll look
at those when I have some bandwidth but overally I think we are
now in pretty acceptable measures :-)

Thanks again for all the effort with testing this!

BR, Jarkko