Re: [PATCH v3] AF_ALG: Initialize sg_num_bytes in error code path

Dmitry Vyukov
2018-07-06T07:58:38Z

On Fri, Jul 6, 2018 at 9:50 AM, Stephan Müller <smueller@chronox.de> wrote:
> Changes v3:
> * Fix syz testing line

Just in case, the syz test does not have to be in the patch. Just an
email to the syzbot address will do.

> Changes v2:
> * Addition of syz testing line
>
> ---8<---
>
> The RX SGL in processing is already registered with the RX SGL tracking
> list to support proper cleanup. The cleanup code path uses the
> sg_num_bytes variable which must therefore be always initialized, even
> in the error code path.
>
> Signed-off-by: Stephan Mueller <smueller@chronox.de>
> Reported-by: syzbot+9c251bdd09f83b92ba95@syzkaller.appspotmail.com
> #syz test: https://github.com/google/kmsan.git master
> ---
> crypto/af_alg.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/crypto/af_alg.c b/crypto/af_alg.c
> index 49fa8582138b..bd6795ff406a 100644
> --- a/crypto/af_alg.c
> +++ b/crypto/af_alg.c
> @@ -1148,8 +1148,10 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
>
> /* make one iovec available as scatterlist */
> err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
> - if (err < 0)
> + if (err < 0) {
> + rsgl->sg_num_bytes = 0;
> return err;
> + }
>
> /* chain the new scatterlist with previous one */
> if (areq->last_rsgl)
> --
> 2.17.1
>
>
>
>
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