| Message ID | 20250407072057.81062-1-jarkko@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] tpm: Mask TPM RC in tpm2_start_auth_session() | expand |
On Mon, Apr 07, 2025 at 10:20:57AM +0300, Jarkko Sakkinen wrote: >tpm2_start_auth_session() does not mask TPM RC correctly from the callers: > >[ 28.766528] tpm tpm0: A TPM error (2307) occurred start auth session > >Process TPM RCs inside tpm2_start_auth_session(), and map them to POSIX >error codes. > >Cc: stable@vger.kernel.org # v6.10+ >Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions") >Reported-by: Herbert Xu <herbert@gondor.apana.org.au> >Closes: https://lore.kernel.org/linux-integrity/Z_NgdRHuTKP6JK--@gondor.apana.org.au/ >Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> >--- >v3: >- rc > 0 >v2: >- Investigate TPM rc only after destroying tpm_buf. >--- > drivers/char/tpm/tpm2-sessions.c | 31 +++++++++++++++++-------------- > include/linux/tpm.h | 1 + > 2 files changed, 18 insertions(+), 14 deletions(-) > >diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c >index 3f89635ba5e8..abd54fb0a45a 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 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key) > } > > /** >- * 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_transmit_cmd(chip, &buf, 0, "StartAuthSession"); > tpm2_flush_context(chip, null_key); > > if (rc == TPM2_RC_SUCCESS) >@@ -1032,6 +1024,17 @@ int tpm2_start_auth_session(struct tpm_chip *chip) > > tpm_buf_destroy(&buf); > >+ if (rc > 0) { To avoid the nesting blocks, can we include `TPM2_RC_SUCCESS` case in the switch or move the `if (rc == TPM2_RC_SUCCESS)` before it? Thanks, Stefano >+ switch (rc) { >+ case TPM2_RC_SESSION_MEMORY: >+ rc = -ENOMEM; >+ goto out; >+ default: >+ rc = -EFAULT; >+ goto out; >+ } >+ } >+ > if (rc == TPM2_RC_SUCCESS) { > chip->auth = auth; > return 0; >diff --git a/include/linux/tpm.h b/include/linux/tpm.h >index 6c3125300c00..c1d3d60b416f 100644 >--- a/include/linux/tpm.h >+++ b/include/linux/tpm.h >@@ -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 { >-- >2.39.5 > >
On Mon, Apr 07, 2025 at 10:04:09AM +0200, Stefano Garzarella wrote: > On Mon, Apr 07, 2025 at 10:20:57AM +0300, Jarkko Sakkinen wrote: > > tpm2_start_auth_session() does not mask TPM RC correctly from the callers: > > > > [ 28.766528] tpm tpm0: A TPM error (2307) occurred start auth session > > > > Process TPM RCs inside tpm2_start_auth_session(), and map them to POSIX > > error codes. > > > > Cc: stable@vger.kernel.org # v6.10+ > > Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions") > > Reported-by: Herbert Xu <herbert@gondor.apana.org.au> > > Closes: https://lore.kernel.org/linux-integrity/Z_NgdRHuTKP6JK--@gondor.apana.org.au/ > > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> > > --- > > v3: > > - rc > 0 > > v2: > > - Investigate TPM rc only after destroying tpm_buf. > > --- > > drivers/char/tpm/tpm2-sessions.c | 31 +++++++++++++++++-------------- > > include/linux/tpm.h | 1 + > > 2 files changed, 18 insertions(+), 14 deletions(-) > > > > diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c > > index 3f89635ba5e8..abd54fb0a45a 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 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key) > > } > > > > /** > > - * 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_transmit_cmd(chip, &buf, 0, "StartAuthSession"); > > tpm2_flush_context(chip, null_key); > > > > if (rc == TPM2_RC_SUCCESS) > > @@ -1032,6 +1024,17 @@ int tpm2_start_auth_session(struct tpm_chip *chip) > > > > tpm_buf_destroy(&buf); > > > > + if (rc > 0) { > > To avoid the nesting blocks, can we include `TPM2_RC_SUCCESS` case in the > switch or move the `if (rc == TPM2_RC_SUCCESS)` before it? What do you mean by "avoiding nesting blocks"? > > Thanks, > Stefano BR, Jarkko
On Mon, Apr 07, 2025 at 02:30:05PM +0300, Jarkko Sakkinen wrote: >On Mon, Apr 07, 2025 at 10:04:09AM +0200, Stefano Garzarella wrote: >> On Mon, Apr 07, 2025 at 10:20:57AM +0300, Jarkko Sakkinen wrote: >> > tpm2_start_auth_session() does not mask TPM RC correctly from the callers: >> > >> > [ 28.766528] tpm tpm0: A TPM error (2307) occurred start auth session >> > >> > Process TPM RCs inside tpm2_start_auth_session(), and map them to POSIX >> > error codes. >> > >> > Cc: stable@vger.kernel.org # v6.10+ >> > Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions") >> > Reported-by: Herbert Xu <herbert@gondor.apana.org.au> >> > Closes: https://lore.kernel.org/linux-integrity/Z_NgdRHuTKP6JK--@gondor.apana.org.au/ >> > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> >> > --- >> > v3: >> > - rc > 0 >> > v2: >> > - Investigate TPM rc only after destroying tpm_buf. >> > --- >> > drivers/char/tpm/tpm2-sessions.c | 31 +++++++++++++++++-------------- >> > include/linux/tpm.h | 1 + >> > 2 files changed, 18 insertions(+), 14 deletions(-) >> > >> > diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c >> > index 3f89635ba5e8..abd54fb0a45a 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 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key) >> > } >> > >> > /** >> > - * 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_transmit_cmd(chip, &buf, 0, "StartAuthSession"); >> > tpm2_flush_context(chip, null_key); >> > >> > if (rc == TPM2_RC_SUCCESS) >> > @@ -1032,6 +1024,17 @@ int tpm2_start_auth_session(struct tpm_chip *chip) >> > >> > tpm_buf_destroy(&buf); >> > >> > + if (rc > 0) { >> >> To avoid the nesting blocks, can we include `TPM2_RC_SUCCESS` case in the >> switch or move the `if (rc == TPM2_RC_SUCCESS)` before it? > >What do you mean by "avoiding nesting blocks"? Ooops, I thought `rc` was unsigned always returning TPM2_RC_* values, but it looks it's not the case. I meant the switch "block" inside the if block, at the end exactly what you did in tpm_to_ret() in v4 :-) Thanks, Stefano
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c index 3f89635ba5e8..abd54fb0a45a 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 @@ static int tpm2_load_null(struct tpm_chip *chip, u32 *null_key) } /** - * 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_transmit_cmd(chip, &buf, 0, "StartAuthSession"); tpm2_flush_context(chip, null_key); if (rc == TPM2_RC_SUCCESS) @@ -1032,6 +1024,17 @@ int tpm2_start_auth_session(struct tpm_chip *chip) tpm_buf_destroy(&buf); + if (rc > 0) { + switch (rc) { + case TPM2_RC_SESSION_MEMORY: + rc = -ENOMEM; + goto out; + default: + rc = -EFAULT; + goto out; + } + } + if (rc == TPM2_RC_SUCCESS) { chip->auth = auth; return 0; diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 6c3125300c00..c1d3d60b416f 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -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 {
tpm2_start_auth_session() does not mask TPM RC correctly from the callers: [ 28.766528] tpm tpm0: A TPM error (2307) occurred start auth session Process TPM RCs inside tpm2_start_auth_session(), and map them to POSIX error codes. Cc: stable@vger.kernel.org # v6.10+ Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions") Reported-by: Herbert Xu <herbert@gondor.apana.org.au> Closes: https://lore.kernel.org/linux-integrity/Z_NgdRHuTKP6JK--@gondor.apana.org.au/ Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> --- v3: - rc > 0 v2: - Investigate TPM rc only after destroying tpm_buf. --- drivers/char/tpm/tpm2-sessions.c | 31 +++++++++++++++++-------------- include/linux/tpm.h | 1 + 2 files changed, 18 insertions(+), 14 deletions(-)