Thread (22 messages) read the whole thread 22 messages, 5 authors, 2018-07-13

Re: [PATCH] AF_ALG: register completely initialized request in list

From: Dmitry Vyukov <dvyukov@google.com>
Date: 2018-04-09 07:51:36
Also in: lkml

On Sun, Apr 8, 2018 at 7:57 PM, Stephan Müller [off-list ref] 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



quoted hunk ↗ jump to hunk
The fix below should ensure this now.

Thanks a lot.

---8<---

From 8f083e7b0684a9f91c186d7b46eec34e439689c3 Mon Sep 17 00:00:00 2001
From: Stephan Mueller <redacted>
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 <redacted>
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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