From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CA8D047ACD4; Sat, 12 Sep 2026 18:32:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789237926; cv=none; b=YnbQlSmg0YeIKgkzCoAUbLI5bvijVse6qzPpHoQV3yzYqw7iAMGOIqdU8EKJSxDXq27Hq/mqo/1aYYu0XvFz667p55ete8prEj3ja1XTHNO9DrltbunXpWPA7pO3fWMATD6vtoQH0+cknFXwyUYi8GliafwS95/QJjRY8EHzFvc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789237926; c=relaxed/simple; bh=CLVC/Ddep2dVO55D92QwUCFfzigQS3E6qDcpA21B3I8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=O2obNhx0DFOaqpSsnXOO0BGcUPyYqZO3r7i3Hvh/A32iJzFonXUwt5FM53IUPutOxSwOTUViDKweXr/AeaOF3tnNHr5XdDOAiwmez+QOjA5dnn1iEd+tIREFiK/P/u03bjYwqbEy2PpDkoXwx8QA0125hBNKzsgi9++ZBpjAnTQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=THgHKfbZ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="THgHKfbZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0CCF1F00893; Sat, 12 Sep 2026 18:32:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789237922; bh=0B1IwpsoModf3+6otw1U1LxILcYQ2k6cOtAPKk1amX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=THgHKfbZd+au0KqLY3ZIjk5XnK3k7I1Ri1xWSNeXrgk66Bp+LhYUEVtv6606rKFmK tRFpGIpVipqAfmfUA+nLWi6/idWP42kINBvRkj5cOc5lKRduEZHyNAgWZqrlc2P+5M hzo1oJV0qwvRCpOZnvuNKTDvuwQpBbo+Zq6bKhlc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bryam Vargas , Hans Verkuil Subject: [PATCH 5.15 313/935] media: cx231xx: reject geometry changes while the VBI queue is busy Date: Sat, 12 Sep 2026 08:55:43 +0200 Message-ID: <20260912065533.983986800@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065526.833703348@linuxfoundation.org> References: <20260912065526.833703348@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bryam Vargas commit 627a121c15fe05a541f44d86016294b80bada75d upstream. vidioc_s_fmt_vid_cap() and vidioc_s_std() change the device-wide dev->width / dev->norm but only refuse the change when the *video* queue (dev->vidq) is busy. The VBI queue (dev->vbiq) shares that same geometry: cx231xx_init_vbi_isoc() latches dma_q->lines_per_field from dev->norm, the VBI videobuf2 plane is sized from dev->width / dev->norm in vbi_queue_setup() and vbi_buf_prepare(), and cx231xx_do_vbi_copy() then recomputes the destination offset from the *live* dev->width and the latched lines_per_field on every URB completion: offset = lines_completed * (dev->width << 1) + ...; if (dma_q->current_field == 2) offset += dev->width * 2 * dma_q->lines_per_field; memcpy(plane + offset, p_buffer, lencopy); Because the VBI node shares video_ioctl_ops with the video node, an application can size a small VBI plane (REQBUFS/QBUF with a small width, or with the NTSC standard), then enlarge dev->width (or switch dev->norm to PAL) through the video node while the VBI stream is running -- the change is allowed because only dev->vidq is checked -- and let the device deliver a field-2 VBI payload. cx231xx_do_vbi_copy() now computes the offset with the larger geometry and memcpy()s past the end of the smaller plane that was already allocated, a heap out-of-bounds write whose offset is attacker-chosen and whose contents come from the device. The per-field guard in cx231xx_copy_vbi_line() does not help: it bounds the copy against the latched lines_per_field, not the plane's real capacity, and vb2 does not re-run buf_prepare() for an already prepared buffer. Refuse the format/standard change when the VBI queue is busy as well, so the geometry cannot change underneath an allocated VBI buffer. Fixes: 7c617138b825 ("media: cx231xx: convert to the vb2 framework") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Signed-off-by: Hans Verkuil Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/cx231xx/cx231xx-video.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/media/usb/cx231xx/cx231xx-video.c +++ b/drivers/media/usb/cx231xx/cx231xx-video.c @@ -899,7 +899,7 @@ static int vidioc_s_fmt_vid_cap(struct f if (rc) return rc; - if (vb2_is_busy(&dev->vidq)) { + if (vb2_is_busy(&dev->vidq) || vb2_is_busy(&dev->vbiq)) { dev_err(dev->dev, "%s: queue busy\n", __func__); return -EBUSY; } @@ -934,7 +934,7 @@ static int vidioc_s_std(struct file *fil if (dev->norm == norm) return 0; - if (vb2_is_busy(&dev->vidq)) + if (vb2_is_busy(&dev->vidq) || vb2_is_busy(&dev->vbiq)) return -EBUSY; dev->norm = norm;