---
v8:
- Since auth session and null key are flushed at a same time, only
either needs to be checked. Addresses and a remark from James
Bottomley few revisions ago.
- kfree_sensitive()
- Effectively squash top three patches given the simplifications.
v7:
- No changes.
v6:
- No changes.
v5:
- No changes.
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 | 10 +++++++
drivers/char/tpm/tpm-dev-common.c | 3 +++
drivers/char/tpm/tpm-interface.c | 6 +++--
drivers/char/tpm/tpm2-sessions.c | 45 ++++++++++++++++++-------------
4 files changed, 44 insertions(+), 20 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 854546000c92..1ff99a7091bb 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 30b4c288c1bb..c7a88fa7b0fc 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 5da134f12c9a..8134f002b121 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 950a3e48293b..03145a465b5d 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;
}
#endif /* CONFIG_TCG_TPM2_HMAC */
