From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C2D8A1C3BE9; Wed, 19 Feb 2025 09:00:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739955634; cv=none; b=bxbDP9CKYrHSgo2Qv2c8f7xKKwcDMgBlO9OzkIvbT1LQbet3ebqwnXpFHXYZ0CotqY42dH21pfpdWBO2OCkFO7PhzAd1dZNikfvpWG+RQ/gnP4cO/Pm5BfGVpHV5w9OqTKgOMVM4nY7oc6BjLOh2O+sXR6jciPjdbu0W2lvoPww= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739955634; c=relaxed/simple; bh=QNps/2cFAfRkU/khZx4Uwx+8goqMXsTmkqW/E1bYHC0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EaqfGbSvJOSDr3PogdWNZAqt6JQ6oTFgu4lEXmEJTv6mdF4ApH3UEKRdPYG4qCrJsicMMtPm5I4OVY5kQ6V/ZcSxeqBhm6/ebHiKLpZ1LXr98vZy1FxanhTrhBBYxHZWUTeavHl7xmZXdBO0FuF6iUXizl1juqi/JDwXSb5737k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YcuEP57g; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="YcuEP57g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4236EC4CED1; Wed, 19 Feb 2025 09:00:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739955634; bh=QNps/2cFAfRkU/khZx4Uwx+8goqMXsTmkqW/E1bYHC0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YcuEP57gCxZXZra8C16I8dmGMsnQS7CIXBj0+4Wr1AOQJuf7CIvlg1eTolm3tfqaQ CrEE1PfiIh7ogkEiWsS6TIQu4SZoaP5ADMr4fhVqgf+HoNheyC9gr1YAZuXx232jy6 OYKMoyib1fc4u1RCFGPNjusUeft7WpTsvPDIVLGc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+5e248227c80a3be8e96a@syzkaller.appspotmail.com, Edward Adam Davis , Hans Verkuil , Sasha Levin Subject: [PATCH 6.6 035/152] media: vidtv: Fix a null-ptr-deref in vidtv_mux_stop_thread Date: Wed, 19 Feb 2025 09:27:28 +0100 Message-ID: <20250219082551.427994785@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250219082550.014812078@linuxfoundation.org> References: <20250219082550.014812078@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Edward Adam Davis [ Upstream commit 1221989555db711578a327a9367f1be46500cb48 ] syzbot report a null-ptr-deref in vidtv_mux_stop_thread. [1] If dvb->mux is not initialized successfully by vidtv_mux_init() in the vidtv_start_streaming(), it will trigger null pointer dereference about mux in vidtv_mux_stop_thread(). Adjust the timing of streaming initialization and check it before stopping it. [1] KASAN: null-ptr-deref in range [0x0000000000000128-0x000000000000012f] CPU: 0 UID: 0 PID: 5842 Comm: syz-executor248 Not tainted 6.13.0-rc4-syzkaller-00012-g9b2ffa6148b1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:vidtv_mux_stop_thread+0x26/0x80 drivers/media/test-drivers/vidtv/vidtv_mux.c:471 Code: 90 90 90 90 66 0f 1f 00 55 53 48 89 fb e8 82 2e c8 f9 48 8d bb 28 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 02 7e 3b 0f b6 ab 28 01 00 00 31 ff 89 ee e8 RSP: 0018:ffffc90003f2faa8 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87cfb125 RDX: 0000000000000025 RSI: ffffffff87d120ce RDI: 0000000000000128 RBP: ffff888029b8d220 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000003 R12: ffff888029b8d188 R13: ffffffff8f590aa0 R14: ffffc9000581c5c8 R15: ffff888029a17710 FS: 00007f7eef5156c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7eef5e635c CR3: 0000000076ca6000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vidtv_stop_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:209 [inline] vidtv_stop_feed+0x151/0x250 drivers/media/test-drivers/vidtv/vidtv_bridge.c:252 dmx_section_feed_stop_filtering+0x90/0x160 drivers/media/dvb-core/dvb_demux.c:1000 dvb_dmxdev_feed_stop.isra.0+0x1ee/0x270 drivers/media/dvb-core/dmxdev.c:486 dvb_dmxdev_filter_stop+0x22a/0x3a0 drivers/media/dvb-core/dmxdev.c:559 dvb_dmxdev_filter_free drivers/media/dvb-core/dmxdev.c:840 [inline] dvb_demux_release+0x92/0x550 drivers/media/dvb-core/dmxdev.c:1246 __fput+0x3f8/0xb60 fs/file_table.c:450 task_work_run+0x14e/0x250 kernel/task_work.c:239 get_signal+0x1d3/0x2610 kernel/signal.c:2790 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reported-by: syzbot+5e248227c80a3be8e96a@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5e248227c80a3be8e96a Signed-off-by: Edward Adam Davis Signed-off-by: Hans Verkuil Signed-off-by: Sasha Levin --- drivers/media/test-drivers/vidtv/vidtv_bridge.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/media/test-drivers/vidtv/vidtv_bridge.c b/drivers/media/test-drivers/vidtv/vidtv_bridge.c index 8b04e12af286c..6e030584d598a 100644 --- a/drivers/media/test-drivers/vidtv/vidtv_bridge.c +++ b/drivers/media/test-drivers/vidtv/vidtv_bridge.c @@ -191,10 +191,11 @@ static int vidtv_start_streaming(struct vidtv_dvb *dvb) mux_args.mux_buf_sz = mux_buf_sz; - dvb->streaming = true; dvb->mux = vidtv_mux_init(dvb->fe[0], dev, &mux_args); if (!dvb->mux) return -ENOMEM; + + dvb->streaming = true; vidtv_mux_start_thread(dvb->mux); dev_dbg_ratelimited(dev, "Started streaming\n"); @@ -205,6 +206,11 @@ static int vidtv_stop_streaming(struct vidtv_dvb *dvb) { struct device *dev = &dvb->pdev->dev; + if (!dvb->streaming) { + dev_warn_ratelimited(dev, "No streaming. Skipping.\n"); + return 0; + } + dvb->streaming = false; vidtv_mux_stop_thread(dvb->mux); vidtv_mux_destroy(dvb->mux); -- 2.39.5