X.509: Fix crash caused by NULL pointer

commit 7178a107f5ea7bdb1cc23073234f0ded0ef90ec7 upstream.

On the following call path, `sig->pkey_algo` is not assigned
in asymmetric_key_verify_signature(), which causes runtime
crash in public_key_verify_signature().

  keyctl_pkey_verify
    asymmetric_key_verify_signature
      verify_signature
        public_key_verify_signature

This patch simply check this situation and fixes the crash
caused by NULL pointer.

Fixes: 2155256396 ("X.509: support OSCCA SM2-with-SM3 certificate verification")
Reported-by: Tobias Markus <tobias@markus-regensburg.de>
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Toke Høiland-Jørgensen <toke@redhat.com>
Tested-by: João Fonseca <jpedrofonseca@ua.pt>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tianjia Zhang 2021-01-19 00:13:19 +00:00 committed by Greg Kroah-Hartman
parent 5f52a8a71b
commit 90bd4a0cf5

View File

@ -356,7 +356,8 @@ int public_key_verify_signature(const struct public_key *pkey,
if (ret)
goto error_free_key;
if (strcmp(sig->pkey_algo, "sm2") == 0 && sig->data_size) {
if (sig->pkey_algo && strcmp(sig->pkey_algo, "sm2") == 0 &&
sig->data_size) {
ret = cert_sig_digest_update(sig, tfm);
if (ret)
goto error_free_key;