This is a note to let you know that I've just added the patch titled
tpm: Lazily flush the auth session
to the 6.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tpm-lazily-flush-the-auth-session.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 514d33f63cd15cd23c6cd3d505cf3e8223283770
Author: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Date: Mon Oct 28 07:50:01 2024 +0200
tpm: Lazily flush the auth session
[ Upstream commit df745e25098dcb2f706399c0d06dd8d1bab6b6ec ]
Move the allocation of chip->auth to tpm2_start_auth_session() so that this
field can be used as flag to tell whether auth session is active or not.
Instead of flushing and reloading the auth session for every transaction
separately, keep the session open unless /dev/tpm0 is used.
Reported-by: Pengyu Ma <mapengyu@xxxxxxxxx>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219229
Cc: stable@xxxxxxxxxxxxxxx # v6.10+
Fixes: 7ca110f2679b ("tpm: Address !chip->auth in tpm_buf_append_hmac_session*()")
Tested-by: Pengyu Ma <mapengyu@xxxxxxxxx>
Tested-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
Reviewed-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 854546000c92b..1ff99a7091bbb 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -674,6 +674,16 @@ 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) {
+ tpm2_end_auth_session(chip);
+ 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 c3fbbf4d3db79..48ff87444f851 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -27,6 +27,9 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
struct tpm_header *header = (void *)buf;
ssize_t ret, len;
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ tpm2_end_auth_session(chip);
+
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 5da134f12c9a4..8134f002b121f 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -379,10 +379,12 @@ 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) {
+ tpm2_end_auth_session(chip);
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-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index a194535619929..c8fdfe901dfb7 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
@@ -484,7 +487,8 @@ 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 +547,7 @@ 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 +558,7 @@ 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);
@@ -853,7 +856,9 @@ int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf,
if (rc)
/* manually close the session if it wasn't consumed */
tpm2_flush_context(chip, auth->handle);
- memzero_explicit(auth, sizeof(*auth));
+
+ kfree_sensitive(auth);
+ chip->auth = NULL;
} else {
/* reset for next use */
auth->session = TPM_HEADER_SIZE;
@@ -881,7 +886,8 @@ void tpm2_end_auth_session(struct tpm_chip *chip)
return;
tpm2_flush_context(chip, auth->handle);
- memzero_explicit(auth, sizeof(*auth));
+ kfree_sensitive(auth);
+ chip->auth = NULL;
}
EXPORT_SYMBOL(tpm2_end_auth_session);
@@ -962,16 +968,20 @@ 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;
@@ -992,7 +1002,7 @@ 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);
@@ -1014,10 +1024,13 @@ 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:
+out:
+ kfree_sensitive(auth);
return rc;
}
EXPORT_SYMBOL(tpm2_start_auth_session);
@@ -1367,10 +1380,6 @@ int tpm2_sessions_init(struct tpm_chip *chip)
return rc;
}
- chip->auth = kmalloc(sizeof(*chip->auth), GFP_KERNEL);
- if (!chip->auth)
- return -ENOMEM;
-
return rc;
}
EXPORT_SYMBOL(tpm2_sessions_init);
