linux/debian/patches/bugfix/all/netfilter-x_tables-check-fo...

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From: Florian Westphal <fw@strlen.de>
Date: Thu, 10 Mar 2016 01:56:23 +0100
Subject: netfilter: x_tables: check for size overflow
Origin: https://git.kernel.org/cgit/linux/kernel/git/pablo/nf-next.git/commit?id=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 <hawkes@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/x_tables.c | 3 +++
1 file changed, 3 insertions(+)
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -658,6 +658,9 @@ struct xt_table_info *xt_alloc_table_inf
struct xt_table_info *info = NULL;
size_t sz = sizeof(*info) + size;
+ 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;