From 1d82cce6f3d3119c33aed88ed8c94f93341f995a Mon Sep 17 00:00:00 2001 From: Ang Way Chuang Date: Fri, 13 Oct 2006 18:01:44 +0200 Subject: [PATCH] dvb-core: Proper handling ULE SNDU length of 0 (CVE-2006-4623) ULE (Unidirectional Lightweight Encapsulation RFC 4326) decapsulation code has a bug that allows an attacker to send a malformed ULE packet with SNDU length of 0 and bring down the receiving machine. This patch fix the bug and has been tested on version 2.6.17.11. This bug is 100% reproducible and the modified source code (GPL) used to produce this bug will be posted on http://nrg.cs.usm.my/downloads.htm shortly. The kernel will produce a dump during CRC32 checking on faulty ULE packet. Signed-off-by: Ang Way Chuang Signed-off-by: Adrian Bunk --- drivers/media/dvb/dvb-core/dvb_net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/dvb/dvb-core/dvb_net.c b/drivers/media/dvb/dvb-core/dvb_net.c index 6711eb6a058c..bdc491452dad 100644 --- a/drivers/media/dvb/dvb-core/dvb_net.c +++ b/drivers/media/dvb/dvb-core/dvb_net.c @@ -492,7 +492,8 @@ static void dvb_net_ule( struct net_device *dev, const u8 *buf, size_t buf_len ) } else priv->ule_dbit = 0; - if (priv->ule_sndu_len > 32763) { + if (priv->ule_sndu_len > 32763 || + priv->ule_sndu_len < ((priv->ule_dbit) ? 4 : 4 + ETH_ALEN)) { printk(KERN_WARNING "%lu: Invalid ULE SNDU length %u. " "Resyncing.\n", priv->ts_count, priv->ule_sndu_len); priv->ule_sndu_len = 0; -- 2.39.5