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>
This commit is contained in:
Florian Westphal 2010-02-15 18:15:55 +01:00 committed by Patrick McHardy
parent ef00f89f1e
commit 1756de262e

View File

@ -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;
}
}