From: Eric Blake <eblake@redhat.com>
To: qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>,
Thomas Huth <thuth@redhat.com>,
"open list:Network Block Dev..." <qemu-block@nongnu.org>,
Max Reitz <mreitz@redhat.com>
Subject: [Qemu-devel] [PATCH] nbd: Initialize reply on failure
Date: Fri, 19 Jul 2019 10:03:13 -0500 [thread overview]
Message-ID: <20190719150313.29198-1-eblake@redhat.com> (raw)
We've had two separate reports of a caller running into use of
uninitialized data if s->quit is set (one detected by gcc -O3, another
by valgrind), due to checking 'nbd_reply_is_simple(reply) || s->quit'
in the wrong order. Rather than chasing down which callers need to
pre-initialize reply, it's easier to guarantee that reply will always
be set by nbd_co_receive_one_chunk() even on failure.
Reported-by: Thomas Huth <thuth@redhat.com>
Reported-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
Replaces: https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg04477.html
Replaces: https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg03712.html
block/nbd.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/block/nbd.c b/block/nbd.c
index 8d565cc624ec..f751a8e633e5 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -640,6 +640,7 @@ static coroutine_fn int nbd_co_receive_one_chunk(
request_ret, qiov, payload, errp);
if (ret < 0) {
+ memset(reply, 0, sizeof *reply);
s->quit = true;
} else {
/* For assert at loop start in nbd_connection_entry */
--
2.20.1
next reply other threads:[~2019-07-19 15:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-19 15:03 Eric Blake [this message]
2019-07-19 15:17 ` [Qemu-devel] [PATCH] nbd: Initialize reply on failure Andrey Shinkevich
2019-07-19 15:53 ` Philippe Mathieu-Daudé
2019-07-19 16:03 ` Eric Blake
2019-07-19 17:06 ` Eric Blake
2019-07-19 17:15 ` Eric Blake
2019-07-19 17:17 ` Philippe Mathieu-Daudé
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