Patchwork AF_ALG: register completely initialized request in list

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Submitter Stephan Mueller
Date April 8, 2018, 5:57 p.m.
Message ID <3337259.MW9pfDCdka@positron.chronox.de>
Download mbox | patch
Permalink /patch/10328455/
State Changes Requested
Delegated to: Herbert Xu
Headers show

Comments

Stephan Mueller - April 8, 2018, 5:57 p.m.
Hi,

May I ask to check whether this patch fixes the issue? I cannot re-create
the issue with the reproducter. Yet, as far as I understand, you try to
induce errors which shall validate whether the error code paths are correct.

The fix below should ensure this now.

Thanks a lot.

---8<---

From 8f083e7b0684a9f91c186d7b46eec34e439689c3 Mon Sep 17 00:00:00 2001
From: Stephan Mueller <smueller@chronox.de>
Date: Sun, 8 Apr 2018 19:53:59 +0200
Subject: [PATCH] AF_ALG: Initialize sg_num_bytes in error code path

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
---
 crypto/af_alg.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
Dmitry Vyukov - April 9, 2018, 7:51 a.m.
On Sun, Apr 8, 2018 at 7:57 PM, Stephan Müller <smueller@chronox.de> wrote:
> Hi,
>
> May I ask to check whether this patch fixes the issue? I cannot re-create
> the issue with the reproducter. Yet, as far as I understand, you try to
> induce errors which shall validate whether the error code paths are correct.

You can ask syzbot to test by replying to its report email with a test
command, see:
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#communication-with-syzbot

Note that all testing of KMSAN bugs needs to go to KMSAN tree, for details see:
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#kmsan-bugs




> The fix below should ensure this now.
>
> Thanks a lot.
>
> ---8<---
>
> From 8f083e7b0684a9f91c186d7b46eec34e439689c3 Mon Sep 17 00:00:00 2001
> From: Stephan Mueller <smueller@chronox.de>
> Date: Sun, 8 Apr 2018 19:53:59 +0200
> Subject: [PATCH] AF_ALG: Initialize sg_num_bytes in error code path
>
> 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
> ---
>  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 c49766b03165..0d555c072669 100644
> --- a/crypto/af_alg.c
> +++ b/crypto/af_alg.c
> @@ -1156,8 +1156,10 @@ 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)
> --
> 2.14.3
>
>
>
>
>
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Stephan Mueller - April 9, 2018, 7:54 a.m.
Am Montag, 9. April 2018, 09:51:13 CEST schrieb Dmitry Vyukov:

Hi Dmitry,

> You can ask syzbot to test by replying to its report email with a test
> command, see:
> https://github.com/google/syzkaller/blob/master/docs/syzbot.md#communication
> -with-syzbot
> 
> Note that all testing of KMSAN bugs needs to go to KMSAN tree, for details
> see:
> https://github.com/google/syzkaller/blob/master/docs/syzbot.md#kmsan-bugs

Thank you. I will resend the patch later today with the proper tags.

Ciao
Stephan

Patch

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index c49766b03165..0d555c072669 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1156,8 +1156,10 @@  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)