From 1f9352ae2253a97b07b34dcf16ffa3b4ca12c558 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Wed, 25 Mar 2009 19:26:35 +0100 Subject: [PATCH] netfilter: {ip,ip6,arp}_tables: fix incorrect loop detection Commit e1b4b9f ([NETFILTER]: {ip,ip6,arp}_tables: fix exponential worst-case search for loops) introduced a regression in the loop detection algorithm, causing sporadic incorrectly detected loops. When a chain has already been visited during the check, it is treated as having a standard target containing a RETURN verdict directly at the beginning in order to not check it again. The real target of the first rule is then incorrectly treated as STANDARD target and checked not to contain invalid verdicts. Fix by making sure the rule does actually contain a standard target. Based on patch by Francis Dupont Signed-off-by: Patrick McHardy --- net/ipv4/netfilter/arp_tables.c | 4 +++- net/ipv4/netfilter/ip_tables.c | 4 +++- net/ipv6/netfilter/ip6_tables.c | 4 +++- 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 4b35dba7cf7d..4f454ce9a602 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -388,7 +388,9 @@ static int mark_source_chains(struct xt_table_info *newinfo, && unconditional(&e->arp)) || visited) { unsigned int oldpos, size; - if (t->verdict < -NF_MAX_VERDICT - 1) { + if ((strcmp(t->target.u.user.name, + ARPT_STANDARD_TARGET) == 0) && + t->verdict < -NF_MAX_VERDICT - 1) { duprintf("mark_source_chains: bad " "negative verdict (%i)\n", t->verdict); diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 41c59e391a6a..82ee7c9049ff 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -488,7 +488,9 @@ mark_source_chains(struct xt_table_info *newinfo, && unconditional(&e->ip)) || visited) { unsigned int oldpos, size; - if (t->verdict < -NF_MAX_VERDICT - 1) { + if ((strcmp(t->target.u.user.name, + IPT_STANDARD_TARGET) == 0) && + t->verdict < -NF_MAX_VERDICT - 1) { duprintf("mark_source_chains: bad " "negative verdict (%i)\n", t->verdict); diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index e59662b3b5b9..e89cfa3a8f25 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -517,7 +517,9 @@ mark_source_chains(struct xt_table_info *newinfo, && unconditional(&e->ipv6)) || visited) { unsigned int oldpos, size; - if (t->verdict < -NF_MAX_VERDICT - 1) { + if ((strcmp(t->target.u.user.name, + IP6T_STANDARD_TARGET) == 0) && + t->verdict < -NF_MAX_VERDICT - 1) { duprintf("mark_source_chains: bad " "negative verdict (%i)\n", t->verdict); -- GitLab