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tpm: Address !chip->auth in tpm2_*_auth_session()

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Unless tpm_chip_bootstrap() was called by the driver, !chip->auth can cause
a null derefence in tpm2_*_auth_session(). Thus, address !chip->auth in
tpm2_*_auth_session().

Cc: stable@vger.kernel.org # v6.9+
Reported-by: Stefan Berger <stefanb@linux.ibm.com>
Closes: https://lore.kernel.org/linux-integrity/20240617193408.1234365-1-stefanb@linux.ibm.com/
Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions")
Tested-by: Michael Ellerman <mpe@ellerman.id.au> # ppc
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
This commit is contained in:
Jarkko Sakkinen 2024-07-03 19:39:27 +03:00 committed by Jarkko Sakkinen
parent 661e504db0
commit 25ee48a55f
1 changed files with 12 additions and 2 deletions
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14
drivers/char/tpm/tpm2-sessions.c
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@ -824,8 +824,13 @@ EXPORT_SYMBOL(tpm_buf_check_hmac_response);
*/
void tpm2_end_auth_session(struct tpm_chip *chip)
{
tpm2_flush_context(chip, chip->auth->handle);
memzero_explicit(chip->auth, sizeof(*chip->auth));
struct tpm2_auth *auth = chip->auth;
if (!auth)
return;
tpm2_flush_context(chip, auth->handle);
memzero_explicit(auth, sizeof(*auth));
}
EXPORT_SYMBOL(tpm2_end_auth_session);
@ -907,6 +912,11 @@ int tpm2_start_auth_session(struct tpm_chip *chip)
int rc;
u32 null_key;
if (!auth) {
dev_warn_once(&chip->dev, "auth session is not active\n");
return 0;
}
rc = tpm2_load_null(chip, &null_key);
if (rc)
goto out;