From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752267AbcGNIme (ORCPT ); Thu, 14 Jul 2016 04:42:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:55272 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751307AbcGNIQu (ORCPT ); Thu, 14 Jul 2016 04:16:50 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Florian Westphal , Pablo Neira Ayuso , Jiri Slaby Subject: [PATCH 3.12 28/88] netfilter: x_tables: validate targets of jumps Date: Thu, 14 Jul 2016 10:15:20 +0200 Message-Id: <42b891251b3b9f241fb5f0a90e87b15d2fef0a74.1468483951.git.jslaby@suse.cz> X-Mailer: git-send-email 2.9.1 In-Reply-To: <3d4036cb9b963cdd270c02856a888183da0623db.1468483951.git.jslaby@suse.cz> References: <3d4036cb9b963cdd270c02856a888183da0623db.1468483951.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Florian Westphal 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- net/ipv4/netfilter/arp_tables.c | 17 +++++++++++++++++ net/ipv4/netfilter/ip_tables.c | 17 +++++++++++++++++ net/ipv6/netfilter/ip6_tables.c | 17 +++++++++++++++++ 3 files changed, 51 insertions(+) diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 7460b7bef3ab..473ec559ce7b 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -358,6 +358,19 @@ 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 void *entry0, + const struct arpt_entry *target) +{ + struct arpt_entry *iter; + + xt_entry_foreach(iter, entry0, 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 +464,10 @@ 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, entry0, 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 8fc22eed9603..dba9d8070d07 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -434,6 +434,19 @@ ipt_do_table(struct sk_buff *skb, #endif } +static bool find_jump_target(const struct xt_table_info *t, + const void *entry0, + const struct ipt_entry *target) +{ + struct ipt_entry *iter; + + xt_entry_foreach(iter, entry0, 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 +544,10 @@ 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, entry0, 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 63f7876c4f29..97a8d2525c26 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -444,6 +444,19 @@ ip6t_do_table(struct sk_buff *skb, #endif } +static bool find_jump_target(const struct xt_table_info *t, + const void *entry0, + const struct ip6t_entry *target) +{ + struct ip6t_entry *iter; + + xt_entry_foreach(iter, entry0, 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 +554,10 @@ 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, entry0, e)) + return 0; } else { /* ... this is a fallthru */ newpos = pos + e->next_offset; -- 2.9.1