tpm: fix use after free in tpm2_load_context()

commit 8c81c247 upstream.

If load context command returns with TPM2_RC_HANDLE or TPM2_RC_REFERENCE_H0
then we have use after free in line 114 and double free in 117.

Fixes: 4d57856a ("tpm2: add session handle context saving and restoring to the space code")
Cc: stable@vger.kernel.org
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off--by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/tpm/tpm2-space.c

@@ -102,8 +102,9 @@ static int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
 		 * TPM_RC_REFERENCE_H0 means the session has been
 		 * flushed outside the space
 		 */
-		rc = -ENOENT;
+		*handle = 0;
 		tpm_buf_destroy(&tbuf);
+		return -ENOENT;
 	} else if (rc > 0) {
 		dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
 			 __func__, rc);