Commit 25ee48a5 authored by Jarkko Sakkinen's avatar Jarkko Sakkinen Committed by Jarkko Sakkinen
Browse files

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



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: default avatarStefan Berger <stefanb@linux.ibm.com>
Closes: https://lore.kernel.org/linux-integrity/20240617193408.1234365-1-stefanb@linux.ibm.com/


Fixes: 699e3efd ("tpm: Add HMAC session start and end functions")
Tested-by: Michael Ellerman <mpe@ellerman.id.au> # ppc
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent 661e504d

drivers/char/tpm/tpm2-sessions.c

+12 −2
Original line number Diff line number Diff line
@@ -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;