From: Florian Westphal <fw@strlen.de>
To: <netfilter-devel@vger.kernel.org>
Cc: hawkes@google.com, Florian Westphal <fw@strlen.de>
Subject: [PATCH nf] netfilter: x_tables: check for size overflow
Date: Thu, 10 Mar 2016 01:56:23 +0100 [thread overview]
Message-ID: <1457571383-25520-1-git-send-email-fw@strlen.de> (raw)
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>
---
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 c8a0b7d..17a9a9f 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -659,6 +659,9 @@ 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;
--
2.4.10
next reply other threads:[~2016-03-10 0:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-10 0:56 Florian Westphal [this message]
2016-03-12 10:53 ` [PATCH nf] netfilter: x_tables: check for size overflow Pablo Neira Ayuso
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