From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756532AbZKXIEg (ORCPT ); Tue, 24 Nov 2009 03:04:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755097AbZKXIEg (ORCPT ); Tue, 24 Nov 2009 03:04:36 -0500 Received: from mail-px0-f180.google.com ([209.85.216.180]:65520 "EHLO mail-px0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753920AbZKXIEf (ORCPT ); Tue, 24 Nov 2009 03:04:35 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=BMRnPy9NNAY5MAT79/hgaS+W5kBFZI5LxEiKS5r66ZzmYD0N2627j2DcNipZzdQG4H JlYsWiaHFKwsvTXlqrIO2r6sEZY4jE3CgqI7K5HYe/i1vaWuStNgCsFor2ghBYBnWOqY I/PzPPw/SbxgM47EV6uaciniiweyZlD2mVvNE= MIME-Version: 1.0 In-Reply-To: <20091124080006.GB14488@bicker> References: <51d384e10911230137q7553b8c4x5ba3aca3e8edbc77@mail.gmail.com> <20091124080006.GB14488@bicker> Date: Tue, 24 Nov 2009 16:04:41 +0800 Message-ID: <51d384e10911240004t47bb3d18g4e95e52d83b99e06@mail.gmail.com> Subject: Re: [PATCH] dvb-core: Fix ULE decapsulation bug when less than 4 bytes of ULE SNDU is packed into the remaining bytes of a MPEG2-TS frame From: Ang Way Chuang To: Dan Carpenter , Ang Way Chuang , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Okay, resending. Hope it won't do line wrapping. ULE (Unidirectional Lightweight Encapsulation RFC 4326) decapsulation code has a bug that incorrectly treats ULE SNDU packed into the remaining 2 or 3 bytes of a MPEG2-TS frame as having invalid pointer field on the subsequent MPEG2-TS frame. This patch was generated and tested against v2.6.32-rc8. Similar patch was applied and tested using 2.6.27 which is similar to the latest dvb_net.c, except for network device statistical data structure. I suspect that this bug was introduced in kernel version 2.6.15, but had not verified it. Care has been taken not to introduce more bug by fixing this bug, but please scrutinize the code for I always produces buggy code. Signed-off-by: Ang Way Chuang --- diff --git a/drivers/media/dvb/dvb-core/dvb_net.c b/drivers/media/dvb/dvb-core/dvb_net.c index 0241a7c..7e0db86 100644 --- a/drivers/media/dvb/dvb-core/dvb_net.c +++ b/drivers/media/dvb/dvb-core/dvb_net.c @@ -458,8 +458,9 @@ static void dvb_net_ule( struct net_device *dev, const u8 *buf, size_t buf_len ) "field: %u.\n", priv->ts_count, *from_where); /* Drop partly decoded SNDU, reset state, resync on PUSI. */ - if (priv->ule_skb) { - dev_kfree_skb( priv->ule_skb ); + if (priv->ule_skb || priv->ule_sndu_remain) { + if (priv->ule_skb) + dev_kfree_skb( priv->ule_skb ); dev->stats.rx_errors++; dev->stats.rx_frame_errors++; } @@ -533,6 +534,7 @@ static void dvb_net_ule( struct net_device *dev, const u8 *buf, size_t buf_len ) from_where += 2; } + priv->ule_sndu_remain = priv->ule_sndu_len + 2; /* * State of current TS: * ts_remain (remaining bytes in the current TS cell) @@ -542,6 +544,7 @@ static void dvb_net_ule( struct net_device *dev, const u8 *buf, size_t buf_len ) */ switch (ts_remain) { case 1: + priv->ule_sndu_remain--; priv->ule_sndu_type = from_where[0] << 8; priv->ule_sndu_type_1 = 1; /* first byte of ule_type is set. */ ts_remain -= 1; from_where += 1; @@ -555,6 +558,7 @@ static void dvb_net_ule( struct net_device *dev, const u8 *buf, size_t buf_len ) default: /* complete ULE header is present in current TS. */ /* Extract ULE type field. */ if (priv->ule_sndu_type_1) { + priv->ule_sndu_type_1 = 0; priv->ule_sndu_type |= from_where[0]; from_where += 1; /* points to payload start. */ ts_remain -= 1;