netfilter: x_tables: assert minimum target size

commit a08e4e190b866579896c09af59b3bdca821da2cd upstream.

The target size includes the size of the xt_entry_target struct.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 2ad520ccd0067ffe0d2d840a45b2e942aa44e518..1e2ff82d5bf71528276c0acbe121e6d667026b8a 100644 (file)
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -587,6 +587,9 @@ int xt_check_entry_offsets(const void *base,
                return -EINVAL;
 
        t = (void *)(e + target_offset);
+       if (t->u.target_size < sizeof(*t))
+               return -EINVAL;
+
        if (target_offset + t->u.target_size > next_offset)
                return -EINVAL;