[PATCH 4.4 140/192] [PATCH 4.4 11/16] netfilter: x_tables: check for size overflow

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Florian Westphal <f...@strlen.de>

[ Upstream commit d157bd761585605b7882935ffb86286919f62ea1 ]

Ben Hawkes says:
 integer overflow in xt_alloc_table_info, which on 32-bit systems can
 lead to small structure allocation and a copy_from_user based heap
 corruption.

Reported-by: Ben Hawkes <haw...@google.com>
Signed-off-by: Florian Westphal <f...@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/netfilter/x_tables.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -900,6 +900,9 @@ struct xt_table_info *xt_alloc_table_inf
        if (sz < sizeof(*info))
                return NULL;
 
+       if (sz < sizeof(*info))
+               return NULL;
+
        /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
        if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
                return NULL;