netfilter 60/62: ebtables: abort if next_offset is too small

Submitted by Patrick McHardy on Feb. 16, 2010, 2:56 p.m.


Message ID 20100216145639.2796.91630.sendpatchset@x2.localnet
State Accepted
Delegated to: David Miller
Headers show

Commit Message

Patrick McHardy Feb. 16, 2010, 2:56 p.m.
commit 1756de262e41112a8a8927808eb2f03d21fd4786
Author: Florian Westphal <>
Date:   Mon Feb 15 18:15:55 2010 +0100

    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 <>
    Signed-off-by: Patrick McHardy <>

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diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index bcdf02d..4370e96 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,
 			if (left < e->next_offset)
+			if (e->next_offset < sizeof(struct ebt_entry))
+				return -EINVAL;
 			offset += e->next_offset;