From nobody Tue Feb 10 11:15:22 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1763804649408589.7075331791177; Sat, 22 Nov 2025 01:44:09 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vMcwg-0001vk-DN; Fri, 21 Nov 2025 21:01:51 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vMbyy-0000Q5-ST; Fri, 21 Nov 2025 20:00:08 -0500 Received: from isrv.corpit.ru ([212.248.84.144]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vMbyn-00028R-Dg; Fri, 21 Nov 2025 20:00:04 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id EB5FC16CA49; Fri, 21 Nov 2025 21:44:21 +0300 (MSK) Received: from think4mjt.tls.msk.ru (mjtthink.wg.tls.msk.ru [192.168.177.146]) by tsrv.corpit.ru (Postfix) with ESMTP id A6BE9321C85; Fri, 21 Nov 2025 21:44:30 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Grant Millar | Cylo , Eric Blake , Michael Tokarev Subject: [Stable-10.0.7 14/81] io: fix use after free in websocket handshake code Date: Fri, 21 Nov 2025 21:43:13 +0300 Message-ID: <20251121184424.1137669-14-mjt@tls.msk.ru> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=212.248.84.144; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1763804654828018900 From: Daniel P. Berrang=C3=A9 If the QIOChannelWebsock object is freed while it is waiting to complete a handshake, a GSource is leaked. This can lead to the callback firing later on and triggering a use-after-free in the use of the channel. This was observed in the VNC server with the following trace from valgrind: =3D=3D2523108=3D=3D Invalid read of size 4 =3D=3D2523108=3D=3D at 0x4054A24: vnc_disconnect_start (vnc.c:1296) =3D=3D2523108=3D=3D by 0x4054A24: vnc_client_error (vnc.c:1392) =3D=3D2523108=3D=3D by 0x4068A09: vncws_handshake_done (vnc-ws.c:105) =3D=3D2523108=3D=3D by 0x44863B4: qio_task_complete (task.c:197) =3D=3D2523108=3D=3D by 0x448343D: qio_channel_websock_handshake_io (chan= nel-websock.c:588) =3D=3D2523108=3D=3D by 0x6EDB862: UnknownInlinedFun (gmain.c:3398) =3D=3D2523108=3D=3D by 0x6EDB862: g_main_context_dispatch_unlocked.lto_p= riv.0 (gmain.c:4249) =3D=3D2523108=3D=3D by 0x6EDBAE4: g_main_context_dispatch (gmain.c:4237) =3D=3D2523108=3D=3D by 0x45EC79F: glib_pollfds_poll (main-loop.c:287) =3D=3D2523108=3D=3D by 0x45EC79F: os_host_main_loop_wait (main-loop.c:31= 0) =3D=3D2523108=3D=3D by 0x45EC79F: main_loop_wait (main-loop.c:589) =3D=3D2523108=3D=3D by 0x423A56D: qemu_main_loop (runstate.c:835) =3D=3D2523108=3D=3D by 0x454F300: qemu_default_main (main.c:37) =3D=3D2523108=3D=3D by 0x73D6574: (below main) (libc_start_call_main.h:5= 8) =3D=3D2523108=3D=3D Address 0x57a6e0dc is 28 bytes inside a block of size = 103,608 free'd =3D=3D2523108=3D=3D at 0x5F2FE43: free (vg_replace_malloc.c:989) =3D=3D2523108=3D=3D by 0x6EDC444: g_free (gmem.c:208) =3D=3D2523108=3D=3D by 0x4053F23: vnc_update_client (vnc.c:1153) =3D=3D2523108=3D=3D by 0x4053F23: vnc_refresh (vnc.c:3225) =3D=3D2523108=3D=3D by 0x4042881: dpy_refresh (console.c:880) =3D=3D2523108=3D=3D by 0x4042881: gui_update (console.c:90) =3D=3D2523108=3D=3D by 0x45EFA1B: timerlist_run_timers.part.0 (qemu-time= r.c:562) =3D=3D2523108=3D=3D by 0x45EFC8F: timerlist_run_timers (qemu-timer.c:495) =3D=3D2523108=3D=3D by 0x45EFC8F: qemu_clock_run_timers (qemu-timer.c:57= 6) =3D=3D2523108=3D=3D by 0x45EFC8F: qemu_clock_run_all_timers (qemu-timer.= c:663) =3D=3D2523108=3D=3D by 0x45EC765: main_loop_wait (main-loop.c:600) =3D=3D2523108=3D=3D by 0x423A56D: qemu_main_loop (runstate.c:835) =3D=3D2523108=3D=3D by 0x454F300: qemu_default_main (main.c:37) =3D=3D2523108=3D=3D by 0x73D6574: (below main) (libc_start_call_main.h:5= 8) =3D=3D2523108=3D=3D Block was alloc'd at =3D=3D2523108=3D=3D at 0x5F343F3: calloc (vg_replace_malloc.c:1675) =3D=3D2523108=3D=3D by 0x6EE2F81: g_malloc0 (gmem.c:133) =3D=3D2523108=3D=3D by 0x4057DA3: vnc_connect (vnc.c:3245) =3D=3D2523108=3D=3D by 0x448591B: qio_net_listener_channel_func (net-lis= tener.c:54) =3D=3D2523108=3D=3D by 0x6EDB862: UnknownInlinedFun (gmain.c:3398) =3D=3D2523108=3D=3D by 0x6EDB862: g_main_context_dispatch_unlocked.lto_p= riv.0 (gmain.c:4249) =3D=3D2523108=3D=3D by 0x6EDBAE4: g_main_context_dispatch (gmain.c:4237) =3D=3D2523108=3D=3D by 0x45EC79F: glib_pollfds_poll (main-loop.c:287) =3D=3D2523108=3D=3D by 0x45EC79F: os_host_main_loop_wait (main-loop.c:31= 0) =3D=3D2523108=3D=3D by 0x45EC79F: main_loop_wait (main-loop.c:589) =3D=3D2523108=3D=3D by 0x423A56D: qemu_main_loop (runstate.c:835) =3D=3D2523108=3D=3D by 0x454F300: qemu_default_main (main.c:37) =3D=3D2523108=3D=3D by 0x73D6574: (below main) (libc_start_call_main.h:5= 8) =3D=3D2523108=3D=3D The above can be reproduced by launching QEMU with $ qemu-system-x86_64 -vnc localhost:0,websocket=3D5700 and then repeatedly running: for i in {1..100}; do (echo -n "GET / HTTP/1.1" && sleep 0.05) | nc -w 1 localhost 5700 & done CVE-2025-11234 Reported-by: Grant Millar | Cylo Reviewed-by: Eric Blake Signed-off-by: Daniel P. Berrang=C3=A9 (cherry picked from commit b7a1f2ca45c7865b9e98e02ae605a65fc9458ae9) Signed-off-by: Michael Tokarev diff --git a/include/io/channel-websock.h b/include/io/channel-websock.h index e180827c57..6700cf8946 100644 --- a/include/io/channel-websock.h +++ b/include/io/channel-websock.h @@ -61,7 +61,8 @@ struct QIOChannelWebsock { size_t payload_remain; size_t pong_remain; QIOChannelWebsockMask mask; - guint io_tag; + guint hs_io_tag; /* tracking handshake task */ + guint io_tag; /* tracking watch task */ Error *io_err; gboolean io_eof; uint8_t opcode; diff --git a/io/channel-websock.c b/io/channel-websock.c index 5c0df9d6af..7f8eded4ff 100644 --- a/io/channel-websock.c +++ b/io/channel-websock.c @@ -545,6 +545,7 @@ static gboolean qio_channel_websock_handshake_send(QIOC= hannel *ioc, trace_qio_channel_websock_handshake_fail(ioc, error_get_pretty(err= )); qio_task_set_error(task, err); qio_task_complete(task); + wioc->hs_io_tag =3D 0; return FALSE; } =20 @@ -560,6 +561,7 @@ static gboolean qio_channel_websock_handshake_send(QIOC= hannel *ioc, trace_qio_channel_websock_handshake_complete(ioc); qio_task_complete(task); } + wioc->hs_io_tag =3D 0; return FALSE; } trace_qio_channel_websock_handshake_pending(ioc, G_IO_OUT); @@ -586,6 +588,7 @@ static gboolean qio_channel_websock_handshake_io(QIOCha= nnel *ioc, trace_qio_channel_websock_handshake_fail(ioc, error_get_pretty(err= )); qio_task_set_error(task, err); qio_task_complete(task); + wioc->hs_io_tag =3D 0; return FALSE; } if (ret =3D=3D 0) { @@ -597,7 +600,7 @@ static gboolean qio_channel_websock_handshake_io(QIOCha= nnel *ioc, error_propagate(&wioc->io_err, err); =20 trace_qio_channel_websock_handshake_reply(ioc); - qio_channel_add_watch( + wioc->hs_io_tag =3D qio_channel_add_watch( wioc->master, G_IO_OUT, qio_channel_websock_handshake_send, @@ -907,11 +910,12 @@ void qio_channel_websock_handshake(QIOChannelWebsock = *ioc, =20 trace_qio_channel_websock_handshake_start(ioc); trace_qio_channel_websock_handshake_pending(ioc, G_IO_IN); - qio_channel_add_watch(ioc->master, - G_IO_IN, - qio_channel_websock_handshake_io, - task, - NULL); + ioc->hs_io_tag =3D qio_channel_add_watch( + ioc->master, + G_IO_IN, + qio_channel_websock_handshake_io, + task, + NULL); } =20 =20 @@ -922,6 +926,9 @@ static void qio_channel_websock_finalize(Object *obj) buffer_free(&ioc->encinput); buffer_free(&ioc->encoutput); buffer_free(&ioc->rawinput); + if (ioc->hs_io_tag) { + g_source_remove(ioc->hs_io_tag); + } if (ioc->io_tag) { g_source_remove(ioc->io_tag); } @@ -1222,6 +1229,9 @@ static int qio_channel_websock_close(QIOChannel *ioc, buffer_free(&wioc->encinput); buffer_free(&wioc->encoutput); buffer_free(&wioc->rawinput); + if (wioc->hs_io_tag) { + g_clear_handle_id(&wioc->hs_io_tag, g_source_remove); + } if (wioc->io_tag) { g_clear_handle_id(&wioc->io_tag, g_source_remove); } --=20 2.47.3