From cef0e9eb22315f7c5f3126eb5003e3ea0348ee93 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 29 Jul 2019 17:58:10 +0200 Subject: [PATCH] netfilter: ebtables: also count base chain policies commit 3b48300d5cc7c7bed63fddb006c4046549ed4aec upstream. ebtables doesn't include the base chain policies in the rule count, so we need to add them manually when we call into the x_tables core to allocate space for the comapt offset table. This lead syzbot to trigger: WARNING: CPU: 1 PID: 9012 at net/netfilter/x_tables.c:649 xt_compat_add_offset.cold+0x11/0x36 net/netfilter/x_tables.c:649 Reported-by: syzbot+276ddebab3382bbf72db@syzkaller.appspotmail.com Fixes: 2035f3ff8eaa ("netfilter: ebtables: compat: un-break 32bit setsockopt when no rules are present") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/bridge/netfilter/ebtables.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 0bb4d712b80c..995b3842ba7c 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1779,20 +1779,28 @@ static int compat_calc_entry(const struct ebt_entry *e, return 0; } +static int ebt_compat_init_offsets(unsigned int number) +{ + if (number > INT_MAX) + return -EINVAL; + + /* also count the base chain policies */ + number += NF_BR_NUMHOOKS; + + return xt_compat_init_offsets(NFPROTO_BRIDGE, number); +} static int compat_table_info(const struct ebt_table_info *info, struct compat_ebt_replace *newinfo) { unsigned int size = info->entries_size; const void *entries = info->entries; + int ret; newinfo->entries_size = size; - if (info->nentries) { - int ret = xt_compat_init_offsets(NFPROTO_BRIDGE, - info->nentries); - if (ret) - return ret; - } + ret = ebt_compat_init_offsets(info->nentries); + if (ret) + return ret; return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info, entries, newinfo); @@ -2241,11 +2249,9 @@ static int compat_do_replace(struct net *net, void __user *user, xt_compat_lock(NFPROTO_BRIDGE); - if (tmp.nentries) { - ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries); - if (ret < 0) - goto out_unlock; - } + ret = ebt_compat_init_offsets(tmp.nentries); + if (ret < 0) + goto out_unlock; ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); if (ret < 0) -- GitLab