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Patch "netfilter: x_tables: validate targets of jumps" has been added to the 4.6-stable tree

PATCH [email protected] 1 participant 1 message Jun 22, 2016

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This is a note to let you know that I've just added the patch titled

netfilter: x_tables: validate targets of jumps

to the 4.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
netfilter-x_tables-validate-targets-of-jumps.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 36472341017529e2b12573093cc0f68719300997 Mon Sep 17 00:00:00 2001

From: Florian Westphal <[email protected]>
Date: Fri, 1 Apr 2016 14:17:22 +0200
Subject: netfilter: x_tables: validate targets of jumps

From: Florian Westphal <[email protected]>

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 <[email protected]>
Signed-off-by Pablo Neira Ayuso <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 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(+)
net/ipv4/netfilter/arp_tables.c +16 -0
@@ -367,6 +367,18 @@ static inline bool unconditional(const s
 	       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.
  */

@@ -460,6 +472,10 @@ static int mark_source_chains(const stru
 					/* 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;
net/ipv4/netfilter/ip_tables.c +16 -0
@@ -443,6 +443,18 @@ 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

@@ -540,6 +552,10 @@ mark_source_chains(const struct xt_table
 					/* 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;
net/ipv6/netfilter/ip6_tables.c +16 -0
@@ -455,6 +455,18 @@ 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

@@ -552,6 +564,10 @@ mark_source_chains(const struct xt_table
 					/* 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;

Patches currently in stable-queue which might be from [email protected] are

queue-4.6/netfilter-x_tables-add-and-use-xt_check_entry_offsets.patch queue-4.6/netfilter-x_tables-assert-minimum-target-size.patch queue-4.6/netfilter-x_tables-add-compat-version-of-xt_check_entry_offsets.patch queue-4.6/netfilter-x_tables-check-for-bogus-target-offset.patch queue-4.6/netfilter-x_tables-validate-targets-of-jumps.patch queue-4.6/netfilter-x_tables-don-t-move-to-non-existent-next-rule.patch queue-4.6/netfilter-x_tables-kill-check_entry-helper.patch queue-4.6/netfilter-x_tables-check-standard-target-size-too.patch queue-4.6/netfilter-x_tables-validate-all-offsets-and-sizes-in-a-rule.patch