From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0CF95CAC5B0 for ; Fri, 3 Oct 2025 15:05:16 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1v4hJh-00024y-Nx; Fri, 03 Oct 2025 11:03:29 -0400 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 1v4hJX-00020A-Aw for qemu-devel@nongnu.org; Fri, 03 Oct 2025 11:03:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1v4hJJ-0006Hr-Ix for qemu-devel@nongnu.org; Fri, 03 Oct 2025 11:03:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1759503780; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dCEQzebW+7pjzVG3SjMr9mh+IvGu6TYhculdvh310Oo=; b=AAPO8h9Tj1oyc+2D+Rr8Alafl4FYn/xifC48gT6/EgDJH7/T26H46EcyCHxamM5mZxi4Oj TAHQqywi26+Heh69CXt47xmDrwGJFR9x9FGO1lEML3MF9mBVUcsERU1yMIbgd8xSRSG5iC wcgSMAWpghV7Qoh9Kc3Zoeg0H0anHuo= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-584-4RKEWLl4Ntu1-VT-UMFtaw-1; Fri, 03 Oct 2025 11:02:58 -0400 X-MC-Unique: 4RKEWLl4Ntu1-VT-UMFtaw-1 X-Mimecast-MFC-AGG-ID: 4RKEWLl4Ntu1-VT-UMFtaw_1759503777 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CC0AF1800365; Fri, 3 Oct 2025 15:02:56 +0000 (UTC) Received: from toolbx.redhat.com (unknown [10.42.28.145]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id EE12518004D8; Fri, 3 Oct 2025 15:02:54 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Grant Millar | Cylo , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Subject: [PATCH v2 3/3] io: fix use after free in websocket handshake code Date: Fri, 3 Oct 2025 16:02:45 +0100 Message-ID: <20251003150245.3510069-4-berrange@redhat.com> In-Reply-To: <20251003150245.3510069-1-berrange@redhat.com> References: <20251003150245.3510069-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.467, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org 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: ==2523108== Invalid read of size 4 ==2523108== at 0x4054A24: vnc_disconnect_start (vnc.c:1296) ==2523108== by 0x4054A24: vnc_client_error (vnc.c:1392) ==2523108== by 0x4068A09: vncws_handshake_done (vnc-ws.c:105) ==2523108== by 0x44863B4: qio_task_complete (task.c:197) ==2523108== by 0x448343D: qio_channel_websock_handshake_io (channel-websock.c:588) ==2523108== by 0x6EDB862: UnknownInlinedFun (gmain.c:3398) ==2523108== by 0x6EDB862: g_main_context_dispatch_unlocked.lto_priv.0 (gmain.c:4249) ==2523108== by 0x6EDBAE4: g_main_context_dispatch (gmain.c:4237) ==2523108== by 0x45EC79F: glib_pollfds_poll (main-loop.c:287) ==2523108== by 0x45EC79F: os_host_main_loop_wait (main-loop.c:310) ==2523108== by 0x45EC79F: main_loop_wait (main-loop.c:589) ==2523108== by 0x423A56D: qemu_main_loop (runstate.c:835) ==2523108== by 0x454F300: qemu_default_main (main.c:37) ==2523108== by 0x73D6574: (below main) (libc_start_call_main.h:58) ==2523108== Address 0x57a6e0dc is 28 bytes inside a block of size 103,608 free'd ==2523108== at 0x5F2FE43: free (vg_replace_malloc.c:989) ==2523108== by 0x6EDC444: g_free (gmem.c:208) ==2523108== by 0x4053F23: vnc_update_client (vnc.c:1153) ==2523108== by 0x4053F23: vnc_refresh (vnc.c:3225) ==2523108== by 0x4042881: dpy_refresh (console.c:880) ==2523108== by 0x4042881: gui_update (console.c:90) ==2523108== by 0x45EFA1B: timerlist_run_timers.part.0 (qemu-timer.c:562) ==2523108== by 0x45EFC8F: timerlist_run_timers (qemu-timer.c:495) ==2523108== by 0x45EFC8F: qemu_clock_run_timers (qemu-timer.c:576) ==2523108== by 0x45EFC8F: qemu_clock_run_all_timers (qemu-timer.c:663) ==2523108== by 0x45EC765: main_loop_wait (main-loop.c:600) ==2523108== by 0x423A56D: qemu_main_loop (runstate.c:835) ==2523108== by 0x454F300: qemu_default_main (main.c:37) ==2523108== by 0x73D6574: (below main) (libc_start_call_main.h:58) ==2523108== Block was alloc'd at ==2523108== at 0x5F343F3: calloc (vg_replace_malloc.c:1675) ==2523108== by 0x6EE2F81: g_malloc0 (gmem.c:133) ==2523108== by 0x4057DA3: vnc_connect (vnc.c:3245) ==2523108== by 0x448591B: qio_net_listener_channel_func (net-listener.c:54) ==2523108== by 0x6EDB862: UnknownInlinedFun (gmain.c:3398) ==2523108== by 0x6EDB862: g_main_context_dispatch_unlocked.lto_priv.0 (gmain.c:4249) ==2523108== by 0x6EDBAE4: g_main_context_dispatch (gmain.c:4237) ==2523108== by 0x45EC79F: glib_pollfds_poll (main-loop.c:287) ==2523108== by 0x45EC79F: os_host_main_loop_wait (main-loop.c:310) ==2523108== by 0x45EC79F: main_loop_wait (main-loop.c:589) ==2523108== by 0x423A56D: qemu_main_loop (runstate.c:835) ==2523108== by 0x454F300: qemu_default_main (main.c:37) ==2523108== by 0x73D6574: (below main) (libc_start_call_main.h:58) ==2523108== The above can be reproduced by launching QEMU with $ qemu-system-x86_64 -vnc localhost:0,websocket=5700 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 Signed-off-by: Daniel P. Berrangé --- include/io/channel-websock.h | 3 ++- io/channel-websock.c | 22 ++++++++++++++++------ 2 files changed, 18 insertions(+), 7 deletions(-) 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 a50a160e18..cb4dafdebb 100644 --- a/io/channel-websock.c +++ b/io/channel-websock.c @@ -545,6 +545,7 @@ static gboolean qio_channel_websock_handshake_send(QIOChannel *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 = 0; return FALSE; } @@ -560,6 +561,7 @@ static gboolean qio_channel_websock_handshake_send(QIOChannel *ioc, trace_qio_channel_websock_handshake_complete(ioc); qio_task_complete(task); } + wioc->hs_io_tag = 0; return FALSE; } trace_qio_channel_websock_handshake_pending(ioc, G_IO_OUT); @@ -586,6 +588,7 @@ static gboolean qio_channel_websock_handshake_io(QIOChannel *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 = 0; return FALSE; } if (ret == 0) { @@ -597,7 +600,7 @@ static gboolean qio_channel_websock_handshake_io(QIOChannel *ioc, error_propagate(&wioc->io_err, err); trace_qio_channel_websock_handshake_reply(ioc); - qio_channel_add_watch( + wioc->hs_io_tag = 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, 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 = qio_channel_add_watch( + ioc->master, + G_IO_IN, + qio_channel_websock_handshake_io, + task, + NULL); } @@ -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); } @@ -1221,6 +1228,9 @@ 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); } -- 2.50.1