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 X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C641C433E4 for ; Sun, 26 Jul 2020 17:31:00 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EC7D82065C for ; Sun, 26 Jul 2020 17:30:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="J/V3fRTO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EC7D82065C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-kernel-mentees-bounces@lists.linuxfoundation.org Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id AAA1E20796; Sun, 26 Jul 2020 17:30:59 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id iVU+Ef1Mdfrn; Sun, 26 Jul 2020 17:30:58 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id A515E2010F; Sun, 26 Jul 2020 17:30:58 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 7DF98C004F; Sun, 26 Jul 2020 17:30:58 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 1C3E5C004D for ; Sun, 26 Jul 2020 17:30:57 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 055378641E for ; Sun, 26 Jul 2020 17:30:57 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id PnGhRKu9dqco for ; Sun, 26 Jul 2020 17:30:55 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by fraxinus.osuosl.org (Postfix) with ESMTPS id BD9EF863FF for ; Sun, 26 Jul 2020 17:30:55 +0000 (UTC) Received: from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi [81.175.216.236]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 6AFC9304; Sun, 26 Jul 2020 19:30:52 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1595784652; bh=UdBOdl3zi/qG8vkxOz0jQ4rKn6Xodg91lx+efNqwElY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=J/V3fRTO7HzhURiH6YBF1+ryMV1bVsyzMJ/yr/LDzwQt8mkyIqOIOIkmkNBhiVu+w v8ngpJxW6rFXsCmpghPtyUeYGt6zUEsNzlQxefX38gYQOrSCR+gWcFe298cnmgIJKb Gcu1qf9iNVEjObczqVrP099+3n8lpZChOJdhsRm4= Date: Sun, 26 Jul 2020 20:30:44 +0300 From: Laurent Pinchart To: Peilin Ye Message-ID: <20200726173044.GA14755@pendragon.ideasonboard.com> References: <20200726164439.48973-1-yepeilin.cs@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200726164439.48973-1-yepeilin.cs@gmail.com> Cc: Niklas =?utf-8?Q?S=C3=B6derlund?= , Arnd Bergmann , syzkaller-bugs@googlegroups.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Sakari Ailus , Vandana BN , Hans Verkuil , Mauro Carvalho Chehab , Ezequiel Garcia , linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [Linux-kernel-mentees] [PATCH] media/v4l2-core: Fix kernel-infoleak in video_put_user() X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" Hi Peilin, Thank you for the patch. On Sun, Jul 26, 2020 at 12:44:39PM -0400, Peilin Ye wrote: > video_put_user() is copying uninitialized stack memory to userspace. Fix > it by initializing `vb32` using memset(). What makes you think this will fix the issue ? When initializing a structure at declaration time, the fields that are not explicitly specified should be initialized to 0 by the compiler. See https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.cbclx01/strin.htm: If a structure variable is partially initialized, all the uninitialized structure members are implicitly initialized to zero no matter what the storage class of the structure variable is. See the following example: struct one { int a; int b; int c; }; void main() { struct one z1; // Members in z1 do not have default initial values. static struct one z2; // z2.a=0, z2.b=0, and z2.c=0. struct one z3 = {1}; // z3.a=1, z3.b=0, and z3.c=0. } > Reported-and-tested-by: syzbot+79d751604cb6f29fbf59@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?extid=79d751604cb6f29fbf59 > Signed-off-by: Peilin Ye > --- > drivers/media/v4l2-core/v4l2-ioctl.c | 32 +++++++++++++++------------- > 1 file changed, 17 insertions(+), 15 deletions(-) > > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c > index a556880f225a..08909f58dc80 100644 > --- a/drivers/media/v4l2-core/v4l2-ioctl.c > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c > @@ -3210,21 +3210,23 @@ static int video_put_user(void __user *arg, void *parg, unsigned int cmd) > case VIDIOC_DQBUF_TIME32: > case VIDIOC_PREPARE_BUF_TIME32: { > struct v4l2_buffer *vb = parg; > - struct v4l2_buffer_time32 vb32 = { > - .index = vb->index, > - .type = vb->type, > - .bytesused = vb->bytesused, > - .flags = vb->flags, > - .field = vb->field, > - .timestamp.tv_sec = vb->timestamp.tv_sec, > - .timestamp.tv_usec = vb->timestamp.tv_usec, > - .timecode = vb->timecode, > - .sequence = vb->sequence, > - .memory = vb->memory, > - .m.userptr = vb->m.userptr, > - .length = vb->length, > - .request_fd = vb->request_fd, > - }; > + struct v4l2_buffer_time32 vb32; > + > + memset(&vb32, 0, sizeof(vb32)); > + > + vb32.index = vb->index; > + vb32.type = vb->type; > + vb32.bytesused = vb->bytesused; > + vb32.flags = vb->flags; > + vb32.field = vb->field; > + vb32.timestamp.tv_sec = vb->timestamp.tv_sec; > + vb32.timestamp.tv_usec = vb->timestamp.tv_usec; > + vb32.timecode = vb->timecode; > + vb32.sequence = vb->sequence; > + vb32.memory = vb->memory; > + vb32.m.userptr = vb->m.userptr; > + vb32.length = vb->length; > + vb32.request_fd = vb->request_fd; > > if (copy_to_user(arg, &vb32, sizeof(vb32))) > return -EFAULT; -- Regards, Laurent Pinchart _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees