[PATCH 1/7] netfilter: ebtables: abort if next_offset is too small

[Florian Westphal <fw@strlen.de>]

next_offset must be > 0, otherwise this loops forever.
The offset also contains the size of the ebt_entry structure
itself, so anything smaller is invalid.

Signed-off-by: Florian Westphal <fwestphal@astaro.com>
---
 net/bridge/netfilter/ebtables.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 12beb58..1939041 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -442,6 +442,8 @@ static int ebt_verify_pointers(struct ebt_replace *repl,
 				break;
 			if (left < e->next_offset)
 				break;
+			if (e->next_offset < sizeof(struct ebt_entry))
+				return -EINVAL;
 			offset += e->next_offset;
 		}
 	}
-- 
1.6.4.4