Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 30 Nov 2001 13:40:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 30 Nov 2001 13:40:33 -0500 Received: from vti01.vertis.nl ([145.66.4.26]:59153 "EHLO vti01.vertis.nl") by vger.kernel.org with ESMTP id ; Fri, 30 Nov 2001 13:40:23 -0500 Content-Type: text/plain; charset="iso-8859-1" From: Rolf Fokkens To: Stephan von Krawczynski Subject: Re: [PATCH] vanilla 2.4.15 iptables/REDIRECT kernel oops Date: Fri, 30 Nov 2001 19:33:19 -0800 X-Mailer: KMail [version 1.2] In-Reply-To: <20011128165224.5f3dcd8e.skraw@ithnet.com> <01112822302000.01349@home01> <20011130151342.0ef3f171.skraw@ithnet.com> In-Reply-To: <20011130151342.0ef3f171.skraw@ithnet.com> Cc: davem@redhat.com, rusty@rustcorp.com.au, linux-kernel@vger.kernel.org MIME-Version: 1.0 Message-Id: <01113019331901.04864@home01> Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Friday 30 November 2001 06:13, Stephan von Krawczynski wrote: > we have a problem: I talked to David Miller (one of the network > maintainers), and he told me, that sk _must_ be non NULL in this code. He > states netfilter is broken. > So our patch won't make it. We have to investigate the cause of sk=NULL. > Can you describe a possible test-setup? I think I know what may have caused the problem: I patch from Rusty Russell that I forgot about. I use RPM to build kernels, and I forgot to deactivate this patch. So it wasn't a vanilla kernel. Stuped me! Sorry about the confusion. I'll forward you the patch, just for your information: Rolf On Mon, 29 Oct 2001 21:31:57 -0800 (PST) "David S. Miller" wrote: >? ? From: Rusty Russell >? ? Date: Tue, 30 Oct 2001 15:28:12 +1100 >? ? >? ? should the NAT layer be doing skb_unshare() before altering the packet? >? >?I think it should. Agreed. ?The 2.2 masq code didn't do this, and hence the "don't tcpdump on masq host" recommendation. Please try this patch (compiles at least), Rusty. diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.4.13-official/net/ipv4/netfilter/ip_fw_compat.c working-2.4.13-nfunshare/net/ipv4/netfilter/ip_fw_compat.c --- linux-2.4.13-official/net/ipv4/netfilter/ip_fw_compat.c????? Sat Apr 28 07:15:01 2001 +++ working-2.4.13-nfunshare/net/ipv4/netfilter/ip_fw_compat.c?? Wed Oct 31 17:05:53 2001 @@?-78,11 +78,19 @@ ?{ ???????? int ret = FW_BLOCK; ???????? u_int16_t redirpt; +??????? struct sk_buff *nskb; ? ???????? /* Assume worse case: any hook could change packet */ ???????? (*pskb)->nfcache |= NFC_UNKNOWN | NFC_ALTERED; ???????? if ((*pskb)->ip_summed == CHECKSUM_HW) ???????? ??????? (*pskb)->ip_summed = CHECKSUM_NONE; + +??????? /* Firewall rules can alter TOS: raw socket may have clone of + ? ? ? ? ? skb: don't disturb it --RR */ +??????? nskb = skb_unshare(*pskb, GFP_ATOMIC); +??????? if (!nskb) +??????? ??????? return NF_DROP; +??????? *pskb = nskb; ? ???????? switch (hooknum) { ???????? case NF_IP_PRE_ROUTING: diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.4.13-official/net/ipv4/netfilter/ip_nat_core.c working-2.4.13-nfunshare/net/ipv4/netfilter/ip_nat_core.c --- linux-2.4.13-official/net/ipv4/netfilter/ip_nat_core.c?????? Thu May 17 03:31:27 2001 +++ working-2.4.13-nfunshare/net/ipv4/netfilter/ip_nat_core.c??? Wed Oct 31 16:52:06 2001 @@?-734,6 +734,15 @@ ???????? ? synchronize_bh()) can vanish. */ ???????? READ_LOCK(&ip_nat_lock); ???????? for (i = 0; i < info->num_manips; i++) { +??????? ??????? struct sk_buff *nskb; +??????? ??????? /* raw socket may have clone of skb: don't disturb it --RR */ +??????? ??????? nskb = skb_unshare(*pskb, GFP_ATOMIC); +??????? ??????? if (!nskb) { +??????? ??????? ??????? READ_UNLOCK(&ip_nat_lock); +??????? ??????? ??????? return NF_DROP; +??????? ??????? } +??????? ??????? *pskb = nskb; + ???????? ??????? if (info->manips[i].direction == dir ???????? ??????? ? ?&& info->manips[i].hooknum == hooknum) { ???????? ??????? ??????? DEBUGP("Mangling %p: %s to %u.%u.%u.%u %u\n", diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.4.13-official/net/ipv4/netfilter/ipt_TCPMSS.c working-2.4.13-nfunshare/net/ipv4/netfilter/ipt_TCPMSS.c --- linux-2.4.13-official/net/ipv4/netfilter/ipt_TCPMSS.c??????? Mon Oct ?1 05:26:08 2001 +++ working-2.4.13-nfunshare/net/ipv4/netfilter/ipt_TCPMSS.c???? Wed Oct 31 17:00:42 2001 @@?-48,6 +48,13 @@ ???????? u_int16_t tcplen, newtotlen, oldval, newmss; ???????? unsigned int i; ???????? u_int8_t *opt; +??????? struct sk_buff *nskb; + +??????? /* raw socket may have clone of skb: don't disturb it --RR */ +??????? nskb = skb_unshare(*pskb, GFP_ATOMIC); +??????? if (!nskb) +??????? ??????? return NF_DROP; +??????? *pskb = nskb; ? ???????? tcplen = (*pskb)->len - iph->ihl*4; ? diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.4.13-official/net/ipv4/netfilter/ipt_TOS.c working-2.4.13-nfunshare/net/ipv4/netfilter/ipt_TOS.c --- linux-2.4.13-official/net/ipv4/netfilter/ipt_TOS.c?? Mon Oct ?1 05:26:08 2001 +++ working-2.4.13-nfunshare/net/ipv4/netfilter/ipt_TOS.c??????? Wed Oct 31 17:03:11 2001 @@?-19,7 +19,14 @@ ???????? const struct ipt_tos_target_info *tosinfo = targinfo; ? ???????? if ((iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) { +??????? ??????? struct sk_buff *nskb; ???????? ??????? u_int16_t diffs[2]; + +??????? ??????? /* raw socket may have clone of skb: don't disturb it --RR */ +??????? ??????? nskb = skb_unshare(*pskb, GFP_ATOMIC); +??????? ??????? if (!nskb) +??????? ??????? ??????? return NF_DROP; +??????? ??????? *pskb = nskb; ? ???????? ??????? diffs[0] = htons(iph->tos) ^ 0xFFFF; ???????? ??????? iph->tos = (iph->tos & IPTOS_PREC_MASK) | tosinfo->tos; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/