Linux v4.7

1 files changed, 109 insertions, 0 deletions

diff --git a/netfilter-x_tables-deal-with-bogus-nextoffset-values.patch b/netfilter-x_tables-deal-with-bogus-nextoffset-values.patch
new file mode 100644
index 000000000..e6f5fa6f5
--- /dev/null
+++ b/netfilter-x_tables-deal-with-bogus-nextoffset-values.patch
@@ -0,0 +1,109 @@
+From 2b32a7d82223d76ace432305b18c5816cadff878 Mon Sep 17 00:00:00 2001
+From: Florian Westphal <fw () strlen ! de>
+Date: Thu, 10 Mar 2016 00:56:02 -0800
+Subject: [PATCH] netfilter: x_tables: deal with bogus nextoffset values
+
+Ben Hawkes says:
+
+ In the mark_source_chains function (net/ipv4/netfilter/ip_tables.c) it
+ is possible for a user-supplied ipt_entry structure to have a large
+ next_offset field. This field is not bounds checked prior to writing a
+ counter value at the supplied offset.
+
+Problem is that xt_entry_foreach() macro stops iterating once e->next_offset
+is out of bounds, assuming this is the last entry.
+
+With malformed data thats not necessarily the case so we can
+write outside of allocated area later as we might not have walked the
+entire blob.
+
+Fix this by simplifying mark_source_chains -- it already has to check
+if nextoff is in range to catch invalid jumps, so just do the check
+when we move to a next entry as well.
+
+Signed-off-by: Florian Westphal <fw@strlen.de>
+---
+ net/ipv4/netfilter/arp_tables.c | 8 ++++++++
+ net/ipv4/netfilter/ip_tables.c  | 8 ++++++++
+ net/ipv6/netfilter/ip6_tables.c | 6 ++++++
+ 3 files changed, 22 insertions(+)
+
+diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
+index 2033f92..a9b6c76 100644
+--- a/net/ipv4/netfilter/arp_tables.c
++++ b/net/ipv4/netfilter/arp_tables.c
+@@ -376,6 +376,10 @@ static int mark_source_chains(const struct xt_table_info *newinfo,
+ 
+ 				/* Move along one */
+ 				size = e->next_offset;
++
++				if (pos + size > newinfo->size - sizeof(*e))
++					return 0;
++
+ 				e = (struct arpt_entry *)
+ 					(entry0 + pos + size);
+ 				if (pos + size >= newinfo->size)
+@@ -399,6 +403,10 @@ static int mark_source_chains(const struct xt_table_info *newinfo,
+ 					if (newpos >= newinfo->size)
+ 						return 0;
+ 				}
++
++				if (newpos > newinfo->size - sizeof(*e))
++					return 0;
++
+ 				e = (struct arpt_entry *)
+ 					(entry0 + newpos);
+ 				e->counters.pcnt = pos;
+diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
+index 54906e0..7530ecd 100644
+--- a/net/ipv4/netfilter/ip_tables.c
++++ b/net/ipv4/netfilter/ip_tables.c
+@@ -447,6 +447,10 @@ mark_source_chains(const struct xt_table_info *newinfo,
+ 
+ 				/* Move along one */
+ 				size = e->next_offset;
++
++				if (pos + size > newinfo->size - sizeof(*e))
++					return 0;
++
+ 				e = (struct ipt_entry *)
+ 					(entry0 + pos + size);
+ 				if (pos + size >= newinfo->size)
+@@ -470,6 +474,10 @@ mark_source_chains(const struct xt_table_info *newinfo,
+ 					if (newpos >= newinfo->size)
+ 						return 0;
+ 				}
++
++				if (newpos > newinfo->size - sizeof(*e))
++					return 0;
++
+ 				e = (struct ipt_entry *)
+ 					(entry0 + newpos);
+ 				e->counters.pcnt = pos;
+diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
+index 63e06c3..894da69 100644
+--- a/net/ipv6/netfilter/ip6_tables.c
++++ b/net/ipv6/netfilter/ip6_tables.c
+@@ -474,6 +474,8 @@ mark_source_chains(const struct xt_table_info *newinfo,
+ 
+ 				/* Move along one */
+ 				size = e->next_offset;
++				if (pos + size > newinfo->size - sizeof(*e))
++					return 0;
+ 				e = (struct ip6t_entry *)
+ 					(entry0 + pos + size);
+ 				if (pos + size >= newinfo->size)
+@@ -497,6 +499,10 @@ mark_source_chains(const struct xt_table_info *newinfo,
+ 					if (newpos >= newinfo->size)
+ 						return 0;
+ 				}
++
++				if (newpos > newinfo->size - sizeof(*e))
++					return 0;
++
+ 				e = (struct ip6t_entry *)
+ 					(entry0 + newpos);
+ 				e->counters.pcnt = pos;
+-- 
+2.5.5
+