From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] net: ipmr/ip6mr: prevent out-of-bounds vif_table access Date: Fri, 26 Mar 2010 09:51:37 -0700 (PDT) Message-ID: <20100326.095137.165317348.davem@davemloft.net> References: <4BAC823F.8050409@dev.6wind.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: nicolas.dichtel@dev.6wind.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:36251 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752422Ab0CZQvN (ORCPT ); Fri, 26 Mar 2010 12:51:13 -0400 In-Reply-To: <4BAC823F.8050409@dev.6wind.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Nicolas Dichtel Date: Fri, 26 Mar 2010 10:45:35 +0100 > please consider the attached patch about IPv4 and IPv6 multicast. Already fixed by Patrick McHardy recently: commit a50436f2cd6e85794f7e1aad795ca8302177b896 Author: Patrick McHardy Date: Wed Mar 17 06:04:14 2010 +0000 net: ipmr/ip6mr: fix potential out-of-bounds vif_table access mfc_parent of cache entries is used to index into the vif_table and is initialised from mfcctl->mfcc_parent. This can take values of to 2^16-1, while the vif_table has only MAXVIFS (32) entries. The same problem affects ip6mr. Refuse invalid values to fix a potential out-of-bounds access. Unlike the other validity checks, this is checked in ipmr_mfc_add() instead of the setsockopt handler since its unused in the delete path and might be uninitialized. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index 8582e12..0b9d03c 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -802,6 +802,9 @@ static int ipmr_mfc_add(struct net *net, struct mfcctl *mfc, int mrtsock) int line; struct mfc_cache *uc, *c, **cp; + if (mfc->mfcc_parent >= MAXVIFS) + return -ENFILE; + line = MFC_HASH(mfc->mfcc_mcastgrp.s_addr, mfc->mfcc_origin.s_addr); for (cp = &net->ipv4.mfc_cache_array[line]; diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 52e0f74..23e4ac0 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -1113,6 +1113,9 @@ static int ip6mr_mfc_add(struct net *net, struct mf6cctl *mfc, int mrtsock) unsigned char ttls[MAXMIFS]; int i; + if (mfc->mf6cc_parent >= MAXMIFS) + return -ENFILE; + memset(ttls, 255, MAXMIFS); for (i = 0; i < MAXMIFS; i++) { if (IF_ISSET(i, &mfc->mf6cc_ifset))