From: Florian Westphal Date: Wed, 4 Apr 2018 19:13:30 +0000 (+0200) Subject: netfilter: ebtables: don't attempt to allocate 0-sized compat array X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=3f1e53abff84;p=openwrt%2Fstaging%2Fblogic.git netfilter: ebtables: don't attempt to allocate 0-sized compat array Dmitry reports 32bit ebtables on 64bit kernel got broken by a recent change that returns -EINVAL when ruleset has no entries. ebtables however only counts user-defined chains, so for the initial table nentries will be 0. Don't try to allocate the compat array in this case, as no user defined rules exist no rule will need 64bit translation. Reported-by: Dmitry Vyukov Fixes: 7d7d7e02111e9 ("netfilter: compat: reject huge allocation requests") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 032e0fe45940..28a4c3490359 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1825,13 +1825,14 @@ static int compat_table_info(const struct ebt_table_info *info, { unsigned int size = info->entries_size; const void *entries = info->entries; - int ret; newinfo->entries_size = size; - - ret = xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries); - if (ret) - return ret; + if (info->nentries) { + int ret = xt_compat_init_offsets(NFPROTO_BRIDGE, + info->nentries); + if (ret) + return ret; + } return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info, entries, newinfo);