tpm: fix error return code in tpm2_get_cc_attrs_tbl()

commit 1df8399 upstream.

If the total number of commands queried through TPM2_CAP_COMMANDS is
different from that queried through TPM2_CC_GET_CAPABILITY, it indicates
an unknown error. In this case, an appropriate error code -EFAULT should
be returned. However, we currently do not explicitly assign this error
code to 'rc'. As a result, 0 was incorrectly returned.

Cc: stable@vger.kernel.org
Fixes: 58472f5("tpm: validate TPM 2.0 commands")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/tpm/tpm2-cmd.c

@@ -656,6 +656,7 @@ int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
 
 	if (nr_commands !=
 	    be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE + 5])) {
+		rc = -EFAULT;
 		tpm_buf_destroy(&buf);
 		goto out;
 	}