From 932909d9b28d27e807ff8eecb68c7748f6701628 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 8 Mar 2018 12:54:19 +0100 Subject: [PATCH] netfilter: ebtables: fix erroneous reject of last rule The last rule in the blob has next_entry offset that is same as total size. This made "ebtables32 -A OUTPUT -d de:ad:be:ef:01:02" fail on 64 bit kernel. Fixes: b71812168571fa ("netfilter: ebtables: CONFIG_COMPAT: don't trust userland offsets") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebtables.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 254ef9f49567..a94d23b0a9af 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -2119,8 +2119,12 @@ static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base, * offsets are relative to beginning of struct ebt_entry (i.e., 0). */ for (i = 0; i < 4 ; ++i) { - if (offsets[i] >= *total) + if (offsets[i] > *total) return -EINVAL; + + if (i < 3 && offsets[i] == *total) + return -EINVAL; + if (i == 0) continue; if (offsets[i-1] > offsets[i])