From: Florian Westphal <fwestphal@astaro.com>
Date: Mon, 15 Feb 2010 17:15:55 +0000 (+0100)
Subject: netfilter: ebtables: abort if next_offset is too small
X-Git-Tag: firefly_0821_release~9833^2~3055^2~154^2~9
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=1756de262e41112a8a8927808eb2f03d21fd4786;p=firefly-linux-kernel-4.4.55.git

netfilter: ebtables: abort if next_offset is too small

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>
Signed-off-by: Patrick McHardy <kaber@trash.net>
---

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index bcdf02d866b8..4370e9680487 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -444,6 +444,8 @@ static int ebt_verify_pointers(const 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;
 		}
 	}