Re: [Qemu-devel] [PATCH] crypto: afalg: fix a NULL pointer dereference

["Gonglei (Arei)" <arei.gonglei@huawei.com>]

> -----Original Message-----
> From: longpeng
> Sent: Monday, November 06, 2017 2:21 PM
> To: berrange@redhat.com; pbonzini@redhat.com; Gonglei (Arei)
> Cc: longpeng; qemu-devel@nongnu.org
> Subject: [PATCH] crypto: afalg: fix a NULL pointer dereference
> 
> Test-crypto-hash calls qcrypto_hash_bytesv/digest/base64 with
> errp=NULL, this will cause a NULL poniter deference if afalg_driver
> doesn't support requested algos:
>     ret = qcrypto_hash_afalg_driver.hash_bytesv(alg, iov, niov,
>                                                 result, resultlen,
>                                                 errp);
>     if (ret == 0) {
>         return ret;
>     }
> 
>     error_free(*errp);  // <--- here
> 
> So we must check 'errp & *errp' before dereference.
> 
> Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
> ---

Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>

Thanks,
-Gonglei

>  crypto/hash.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/crypto/hash.c b/crypto/hash.c
> index ac59c63..c464c78 100644
> --- a/crypto/hash.c
> +++ b/crypto/hash.c
> @@ -60,7 +60,9 @@ int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
>       * TODO:
>       * Maybe we should treat some afalg errors as fatal
>       */
> -    error_free(*errp);
> +    if (errp && *errp) {
> +        error_free(*errp);
> +    }
>  #endif
> 
>      return qcrypto_hash_lib_driver.hash_bytesv(alg, iov, niov,
> --
> 1.8.3.1
>