[SRU][Wily][PATCH] UBUNTU: SAUCE: (noup) netfilter: x_tables: check for size overflow

Chris J Arges chris.j.arges at canonical.com
Thu Mar 10 18:58:37 UTC 2016


From: Florian Westphal <fw at strlen.de>

BugLink: http://bugs.launchpad.net/bugs/1555353

http://marc.info/?l=netfilter-devel&m=145757136822750&w=2

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 at google.com>
Signed-off-by: Florian Westphal <fw at strlen.de>
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
Signed-off-by: Chris J Arges <chris.j.arges at canonical.com>
---
 net/netfilter/x_tables.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index d324fe7..7884241 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -661,6 +661,9 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size)
 	struct xt_table_info *info = NULL;
 	size_t sz = sizeof(*info) + size;
 
+	if (sz < size || 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;
-- 
2.7.0





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