Re:

Jarkko Sakkinen
2021-01-20T17:34:38Z

On Tue, Jan 19, 2021 at 12:10:33AM +0000, David Howells wrote:
>
> From: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
>
> 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: 215525639631 ("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>
> Cc: stable@vger.kernel.org # v5.10+
> ---

For what it's worth

Acked-by: Jarkko Sakkinen <jarkko@kernel.org>

/Jarkko

>
> crypto/asymmetric_keys/public_key.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
> index 8892908ad58c..788a4ba1e2e7 100644
> --- a/crypto/asymmetric_keys/public_key.c
> +++ b/crypto/asymmetric_keys/public_key.c
> @@ -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;
>
>