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QEMU update to version 4.1.0-87:

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- nbd/server: CVE-2024-7409: Avoid use-after-free when closing server

Signed-off-by: Jiabo Feng <fengjiabo1@huawei.com>
This commit is contained in:
Jiabo Feng 2024-09-18 15:45:18 +08:00
parent 9f9c5c8924
commit 3d643587ea
2 changed files with 95 additions and 1 deletions
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90
nbd-server-CVE-2024-7409-Avoid-use-after-free-when-c.patch Normal file
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@ -0,0 +1,90 @@
From a9fb187686c5f431615a6f48a27806138cc43eb0 Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@redhat.com>
Date: Thu, 22 Aug 2024 09:35:29 -0500
Subject: [PATCH] nbd/server: CVE-2024-7409: Avoid use-after-free when closing
server
Commit 3e7ef738 plugged the use-after-free of the global nbd_server
object, but overlooked a use-after-free of nbd_server->listener.
Although this race is harder to hit, notice that our shutdown path
first drops the reference count of nbd_server->listener, then triggers
actions that can result in a pending client reaching the
nbd_blockdev_client_closed() callback, which in turn calls
qio_net_listener_set_client_func on a potentially stale object.
If we know we don't want any more clients to connect, and have already
told the listener socket to shut down, then we should not be trying to
update the listener socket's associated function.
Reproducer:
> #!/usr/bin/python3
>
> import os
> from threading import Thread
>
> def start_stop():
> while 1:
> os.system('virsh qemu-monitor-command VM \'{"execute": "nbd-server-start",
+"arguments":{"addr":{"type":"unix","data":{"path":"/tmp/nbd-sock"}}}}\'')
> os.system('virsh qemu-monitor-command VM \'{"execute": "nbd-server-stop"}\'')
>
> def nbd_list():
> while 1:
> os.system('/path/to/build/qemu-nbd -L -k /tmp/nbd-sock')
>
> def test():
> sst = Thread(target=start_stop)
> sst.start()
> nlt = Thread(target=nbd_list)
> nlt.start()
>
> sst.join()
> nlt.join()
>
> test()
Fixes: CVE-2024-7409
Fixes: 3e7ef738c8 ("nbd/server: CVE-2024-7409: Close stray clients at server-stop")
CC: qemu-stable@nongnu.org
Reported-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-ID: <20240822143617.800419-2-eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
blockdev-nbd.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 09ad0bdffb..ec51c637d4 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -75,10 +75,13 @@ static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
static void nbd_update_server_watch(NBDServerData *s)
{
- if (!s->max_connections || s->connections < s->max_connections) {
- qio_net_listener_set_client_func(s->listener, nbd_accept, NULL, NULL);
- } else {
- qio_net_listener_set_client_func(s->listener, NULL, NULL, NULL);
+ if (s->listener) {
+ if (!s->max_connections || s->connections < s->max_connections) {
+ qio_net_listener_set_client_func(s->listener, nbd_accept, NULL,
+ NULL);
+ } else {
+ qio_net_listener_set_client_func(s->listener, NULL, NULL, NULL);
+ }
}
}
@@ -96,6 +99,7 @@ static void nbd_server_free(NBDServerData *server)
*/
qio_net_listener_disconnect(server->listener);
object_unref(OBJECT(server->listener));
+ server->listener = NULL;
QLIST_FOREACH_SAFE(conn, &server->conns, next, tmp) {
qio_channel_shutdown(QIO_CHANNEL(conn->cioc), QIO_CHANNEL_SHUTDOWN_BOTH,
NULL);
--
2.41.0.windows.1

6
qemu.spec
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@ -1,6 +1,6 @@
Name: qemu
Version: 4.1.0
Release: 86
Release: 87
Epoch: 10
Summary: QEMU is a generic and open source machine emulator and virtualizer
License: GPLv2 and BSD and MIT and CC-BY-SA-4.0
@ -423,6 +423,7 @@ Patch0410: nbd-server-CVE-2024-7409-Drop-non-negotiating-client.patch
Patch0411: aio-wait.h-introduce-AIO_WAIT_WHILE_UNLOCKED.patch
Patch0412: main-loop.h-introduce-qemu_in_main_thread.patch
Patch0413: nbd-server-CVE-2024-7409-Close-stray-clients-at-serv.patch
Patch0414: nbd-server-CVE-2024-7409-Avoid-use-after-free-when-c.patch
BuildRequires: flex
BuildRequires: bison
@ -823,6 +824,9 @@ getent passwd qemu >/dev/null || \
%endif
%changelog
* Wed Sep 18 2024 Jiabo Feng <fengjiabo1@huawei.com> - 10:4.1.0-87
- nbd/server: CVE-2024-7409: Avoid use-after-free when closing server
* Tue Aug 13 2024 Jiabo Feng <fengjiabo1@huawei.com> - 10:4.1.0-86
- nbd/server: CVE-2024-7409: Close stray clients at server-stop
- main-loop.h: introduce qemu_in_main_thread()