Subject: [PATCH nf] netfilter: x_tables: check for size overflow From: Florian Westphal <fw () strlen ! de> Date: 2016-03-10 0:56:23 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 @@ -897,6 +897,9 @@ 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 < 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