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[Wily,SRU] UBUNTU: SAUCE: netfilter: x_tables: check for size overflow

Message ID 1457624337-22326-1-git-send-email-tim.gardner@canonical.com
State New
Headers show

Commit Message

Tim Gardner March 10, 2016, 3:38 p.m. UTC 
From: Florian Westphal <fw@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@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
 net/netfilter/x_tables.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox

Patch

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index d4aaad7..865cf73 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -658,6 +658,9 @@  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;