From nobody Wed Sep 3 06:46:55 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66188FA374D for ; Mon, 24 Oct 2022 12:35:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234685AbiJXMfn (ORCPT ); Mon, 24 Oct 2022 08:35:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234272AbiJXM3y (ORCPT ); Mon, 24 Oct 2022 08:29:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C2CE2C10A; Mon, 24 Oct 2022 05:04:02 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3456A6121A; Mon, 24 Oct 2022 12:03:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 436B7C433C1; Mon, 24 Oct 2022 12:03:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666613019; bh=T5i1R27xp5nyi5Tgeqhglx5gFkApiPnJX27oHS5I4c0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ffGTDCxR/Ex2VJlspyYHGdCk/Fj6c+SRR4dTAKUxJX0qNIttqZ+Ck1reO6sbsuaT1 G3OfsYnhu3RKZPpeu+WdHjZAso8qEtMLsKAR4KDLVL5BLMsIm5d2dDdkgqgf8QRON6 eOrKjDlrNhwzQ9sECo6X7l2iTKnGZ5Z0kRfNTc8M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zheyu Ma , Hans Verkuil , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 4.19 207/229] media: cx88: Fix a null-ptr-deref bug in buffer_prepare() Date: Mon, 24 Oct 2022 13:32:06 +0200 Message-Id: <20221024113005.892568251@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112959.085534368@linuxfoundation.org> References: <20221024112959.085534368@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Zheyu Ma [ Upstream commit 2b064d91440b33fba5b452f2d1b31f13ae911d71 ] When the driver calls cx88_risc_buffer() to prepare the buffer, the function call may fail, resulting in a empty buffer and null-ptr-deref later in buffer_queue(). The following log can reveal it: [ 41.822762] general protection fault, probably for non-canonical address= 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI [ 41.824488] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000= 000000007] [ 41.828027] RIP: 0010:buffer_queue+0xc2/0x500 [ 41.836311] Call Trace: [ 41.836945] __enqueue_in_driver+0x141/0x360 [ 41.837262] vb2_start_streaming+0x62/0x4a0 [ 41.838216] vb2_core_streamon+0x1da/0x2c0 [ 41.838516] __vb2_init_fileio+0x981/0xbc0 [ 41.839141] __vb2_perform_fileio+0xbf9/0x1120 [ 41.840072] vb2_fop_read+0x20e/0x400 [ 41.840346] v4l2_read+0x215/0x290 [ 41.840603] vfs_read+0x162/0x4c0 Fix this by checking the return value of cx88_risc_buffer() [hverkuil: fix coding style issues] Signed-off-by: Zheyu Ma Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/pci/cx88/cx88-vbi.c | 9 +++--- drivers/media/pci/cx88/cx88-video.c | 43 +++++++++++++++-------------- 2 files changed, 26 insertions(+), 26 deletions(-) diff --git a/drivers/media/pci/cx88/cx88-vbi.c b/drivers/media/pci/cx88/cx8= 8-vbi.c index 58489ea0c1da..7cf2271866d0 100644 --- a/drivers/media/pci/cx88/cx88-vbi.c +++ b/drivers/media/pci/cx88/cx88-vbi.c @@ -144,11 +144,10 @@ static int buffer_prepare(struct vb2_buffer *vb) return -EINVAL; vb2_set_plane_payload(vb, 0, size); =20 - cx88_risc_buffer(dev->pci, &buf->risc, sgt->sgl, - 0, VBI_LINE_LENGTH * lines, - VBI_LINE_LENGTH, 0, - lines); - return 0; + return cx88_risc_buffer(dev->pci, &buf->risc, sgt->sgl, + 0, VBI_LINE_LENGTH * lines, + VBI_LINE_LENGTH, 0, + lines); } =20 static void buffer_finish(struct vb2_buffer *vb) diff --git a/drivers/media/pci/cx88/cx88-video.c b/drivers/media/pci/cx88/c= x88-video.c index 248fb3b6833c..2bc5080198bb 100644 --- a/drivers/media/pci/cx88/cx88-video.c +++ b/drivers/media/pci/cx88/cx88-video.c @@ -452,6 +452,7 @@ static int queue_setup(struct vb2_queue *q, =20 static int buffer_prepare(struct vb2_buffer *vb) { + int ret; struct vb2_v4l2_buffer *vbuf =3D to_vb2_v4l2_buffer(vb); struct cx8800_dev *dev =3D vb->vb2_queue->drv_priv; struct cx88_core *core =3D dev->core; @@ -466,35 +467,35 @@ static int buffer_prepare(struct vb2_buffer *vb) =20 switch (core->field) { case V4L2_FIELD_TOP: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, 0, UNSET, - buf->bpl, 0, core->height); + ret =3D cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, 0, UNSET, + buf->bpl, 0, core->height); break; case V4L2_FIELD_BOTTOM: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, UNSET, 0, - buf->bpl, 0, core->height); + ret =3D cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, UNSET, 0, + buf->bpl, 0, core->height); break; case V4L2_FIELD_SEQ_TB: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, - 0, buf->bpl * (core->height >> 1), - buf->bpl, 0, - core->height >> 1); + ret =3D cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, + 0, buf->bpl * (core->height >> 1), + buf->bpl, 0, + core->height >> 1); break; case V4L2_FIELD_SEQ_BT: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, - buf->bpl * (core->height >> 1), 0, - buf->bpl, 0, - core->height >> 1); + ret =3D cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, + buf->bpl * (core->height >> 1), 0, + buf->bpl, 0, + core->height >> 1); break; case V4L2_FIELD_INTERLACED: default: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, 0, buf->bpl, - buf->bpl, buf->bpl, - core->height >> 1); + ret =3D cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, 0, buf->bpl, + buf->bpl, buf->bpl, + core->height >> 1); break; } dprintk(2, @@ -502,7 +503,7 @@ static int buffer_prepare(struct vb2_buffer *vb) buf, buf->vb.vb2_buf.index, core->width, core->height, dev->fmt->depth, dev->fmt->name, (unsigned long)buf->risc.dma); - return 0; + return ret; } =20 static void buffer_finish(struct vb2_buffer *vb) --=20 2.35.1