[PATCH 3.18 09/86] netfilter: ebtables: CONFIG_COMPAT: drop a bogus WARN_ON

From: Greg Kroah-Hartman
Date: Wed May 15 2019 - 07:00:19 EST


From: Florian Westphal <fw@xxxxxxxxx>

commit 7caa56f006e9d712b44f27b32520c66420d5cbc6 upstream.

It means userspace gave us a ruleset where there is some other
data after the ebtables target but before the beginning of the next rule.

Fixes: 81e675c227ec ("netfilter: ebtables: add CONFIG_COMPAT support")
Reported-by: syzbot+659574e7bcc7f7eb4df7@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/bridge/netfilter/ebtables.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -2042,7 +2042,8 @@ static int ebt_size_mwt(struct compat_eb
if (match_kern)
match_kern->match_size = ret;

- if (WARN_ON(type == EBT_COMPAT_TARGET && size_left))
+ /* rule should have no remaining data after target */
+ if (type == EBT_COMPAT_TARGET && size_left)
return -EINVAL;

match32 = (struct compat_ebt_entry_mwt *) buf;