netfilter: x_tables: assert minimum target size

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>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 1f44bfa8dd94..ec1b7183fff9 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -568,6 +568,9 @@ 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;