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 20CD0C7EE25 for ; Wed, 7 Jun 2023 20:35:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234024AbjFGUfQ (ORCPT ); Wed, 7 Jun 2023 16:35:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234114AbjFGUfD (ORCPT ); Wed, 7 Jun 2023 16:35:03 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F02C72709 for ; Wed, 7 Jun 2023 13:34:56 -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 D16D56452B for ; Wed, 7 Jun 2023 20:34:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2935C433D2; Wed, 7 Jun 2023 20:34:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686170096; bh=TYKqWagi7LEsfJh+w9eDLA4+KzVotDdmn8BCjg7m8pE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R2PX6mb+EUCPcW3q6VX9O45HGO+yq9qidT361QG+B/IPQV13p9JfczpUfUwpstSZK 4UF5yyvKeZsOKQoT8IywNBdRYENguJoRhaxuKnK6/HZi/Z1b5nXdC2ofQ+FOj2f//h nAtpSaJAEr5pC+uM8RD99G7tPZ9MLGFvt9VxX3BY= 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 4.19 43/88] media: dvb-usb: digitv: fix null-ptr-deref in digitv_i2c_xfer() Date: Wed, 7 Jun 2023 22:16:00 +0200 Message-ID: <20230607200900.574998345@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230607200854.030202132@linuxfoundation.org> References: <20230607200854.030202132@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 e66df4fd1a296..6e556a2a74103 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