From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933495AbcHUPiP (ORCPT ); Sun, 21 Aug 2016 11:38:15 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:56004 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751549AbcHUPiN (ORCPT ); Sun, 21 Aug 2016 11:38:13 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Florian Westphal , Pablo Neira Ayuso , Willy Tarreau Subject: [PATCH 3.10 007/180] netfilter: x_tables: validate targets of jumps Date: Sun, 21 Aug 2016 17:28:57 +0200 Message-Id: <1471793510-13022-8-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1471793510-13022-1-git-send-email-w@1wt.eu> References: <1471793510-13022-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Florian Westphal commit 36472341017529e2b12573093cc0f68719300997 upstream. When we see a jump also check that the offset gets us to beginning of a rule (an ipt_entry). The extra overhead is negible, even with absurd cases. 300k custom rules, 300k jumps to 'next' user chain: [ plus one jump from INPUT to first userchain ]: Before: real 0m24.874s user 0m7.532s sys 0m16.076s After: real 0m27.464s user 0m7.436s sys 0m18.840s Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Willy Tarreau --- net/ipv4/netfilter/arp_tables.c | 16 ++++++++++++++++ net/ipv4/netfilter/ip_tables.c | 16 ++++++++++++++++ net/ipv6/netfilter/ip6_tables.c | 16 ++++++++++++++++ 3 files changed, 48 insertions(+) diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 7460b7b..b2adc4b 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -358,6 +358,18 @@ static inline bool unconditional(const struct arpt_entry *e) memcmp(&e->arp, &uncond, sizeof(uncond)) == 0; } +static bool find_jump_target(const struct xt_table_info *t, + const struct arpt_entry *target) +{ + struct arpt_entry *iter; + + xt_entry_foreach(iter, t->entries, t->size) { + if (iter == target) + return true; + } + return false; +} + /* Figures out from what hook each rule can be called: returns 0 if * there are loops. Puts hook bitmask in comefrom. */ @@ -451,6 +463,10 @@ static int mark_source_chains(const struct xt_table_info *newinfo, /* This a jump; chase it. */ duprintf("Jump rule %u -> %u\n", pos, newpos); + e = (struct arpt_entry *) + (entry0 + newpos); + if (!find_jump_target(newinfo, e)) + return 0; } else { /* ... this is a fallthru */ newpos = pos + e->next_offset; diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 8fc22ee..eea26fc 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -434,6 +434,18 @@ ipt_do_table(struct sk_buff *skb, #endif } +static bool find_jump_target(const struct xt_table_info *t, + const struct ipt_entry *target) +{ + struct ipt_entry *iter; + + xt_entry_foreach(iter, t->entries, t->size) { + if (iter == target) + return true; + } + return false; +} + /* Figures out from what hook each rule can be called: returns 0 if there are loops. Puts hook bitmask in comefrom. */ static int @@ -531,6 +543,10 @@ mark_source_chains(const struct xt_table_info *newinfo, /* This a jump; chase it. */ duprintf("Jump rule %u -> %u\n", pos, newpos); + e = (struct ipt_entry *) + (entry0 + newpos); + if (!find_jump_target(newinfo, e)) + return 0; } else { /* ... this is a fallthru */ newpos = pos + e->next_offset; diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 63f7876..5eeec96 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -444,6 +444,18 @@ ip6t_do_table(struct sk_buff *skb, #endif } +static bool find_jump_target(const struct xt_table_info *t, + const struct ip6t_entry *target) +{ + struct ip6t_entry *iter; + + xt_entry_foreach(iter, t->entries, t->size) { + if (iter == target) + return true; + } + return false; +} + /* Figures out from what hook each rule can be called: returns 0 if there are loops. Puts hook bitmask in comefrom. */ static int @@ -541,6 +553,10 @@ mark_source_chains(const struct xt_table_info *newinfo, /* This a jump; chase it. */ duprintf("Jump rule %u -> %u\n", pos, newpos); + e = (struct ip6t_entry *) + (entry0 + newpos); + if (!find_jump_target(newinfo, e)) + return 0; } else { /* ... this is a fallthru */ newpos = pos + e->next_offset; -- 2.8.0.rc2.1.gbe9624a