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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA368C7EE23 for ; Wed, 7 Jun 2023 20:20:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232200AbjFGUUO (ORCPT ); Wed, 7 Jun 2023 16:20:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233090AbjFGUT6 (ORCPT ); Wed, 7 Jun 2023 16:19:58 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7AB12719 for ; Wed, 7 Jun 2023 13:19:37 -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 1268763B83 for ; Wed, 7 Jun 2023 20:18:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25DF7C433EF; Wed, 7 Jun 2023 20:18:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686169121; bh=9n0Rm0CdUXYPz3XVJ4+U1z4/EFHPAc62x10WzMiWaSY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AG3oEMvZfW0Yu1QqRy3nW0m2WnzrfQyc2VpCTpa5pm34AtcYNmgQAfsznooiueiIE NE97y+LWJ96+HickuXPoCtWivrnZRxsicUajN/qrdCFaZ8TkDdyT7FY7k157DqI5MJ pYGFjT3XdRNcOWTZJ3FgchFE5vvmf1AOPk1L1GZ8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wei Chen , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 4.14 22/61] media: dvb-usb: digitv: fix null-ptr-deref in digitv_i2c_xfer() Date: Wed, 7 Jun 2023 22:15:36 +0200 Message-ID: <20230607200842.804419179@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230607200835.310274198@linuxfoundation.org> References: <20230607200835.310274198@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Wei Chen [ Upstream commit 9ded5bd2a49ce3015b7c936743eec0a0e6e11f0c ] In digitv_i2c_xfer, msg is controlled by user. When msg[i].buf is null and msg[i].len is zero, former checks on msg[i].buf would be passed. Malicious data finally reach digitv_i2c_xfer. If accessing msg[i].buf[0] without sanity check, null ptr deref would happen. We add check on msg[i].len to prevent crash. Similar commit: commit 0ed554fd769a ("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()") Link: https://lore.kernel.org/linux-media/20230313095008.1039689-1-harperchen1110@gmail.com Signed-off-by: Wei Chen Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/usb/dvb-usb/digitv.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c index 20d33f0544ed2..0e2cffa946f69 100644 --- a/drivers/media/usb/dvb-usb/digitv.c +++ b/drivers/media/usb/dvb-usb/digitv.c @@ -66,6 +66,10 @@ static int digitv_i2c_xfer(struct i2c_adapter *adap,struct i2c_msg msg[],int num warn("more than 2 i2c messages at a time is not handled yet. TODO."); for (i = 0; i < num; i++) { + if (msg[i].len < 1) { + i = -EOPNOTSUPP; + break; + } /* write/read request */ if (i+1 < num && (msg[i+1].flags & I2C_M_RD)) { if (digitv_ctrl_msg(d, USB_READ_COFDM, msg[i].buf[0], NULL, 0, -- 2.39.2