[Devel] [PATCH] netfilter: account ebt_table_info to kmemcg

[Kirill Tkhai]

[This is not in ms kernel yet, but we are not interested in waiting
 for next iteration (comment changing was reuested).
 https://lkml.org/lkml/2018/12/28/457]

The [ip,ip6,arp]_tables use x_tables_info internally and the underlying
memory is already accounted to kmemcg. Do the same for ebtables. The
syzbot, by using setsockopt(EBT_SO_SET_ENTRIES), was able to OOM the
whole system from a restricted memcg, a potential DoS.

Reported-by: syzbot+7713f3aa67be76b1552c at syzkaller.appspotmail.com
Signed-off-by: Shakeel Butt <shakeelb at google.com>
Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 net/bridge/netfilter/ebtables.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 793527b15a78..3b06a7d6d1ce 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1131,14 +1131,16 @@ static int do_replace(struct net *net, const void __user *user,
 	tmp.name[sizeof(tmp.name) - 1] = 0;
 
 	countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
-	newinfo = vmalloc(sizeof(*newinfo) + countersize);
+	newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT,
+			    PAGE_KERNEL);
 	if (!newinfo)
 		return -ENOMEM;
 
 	if (countersize)
 		memset(newinfo->counters, 0, countersize);
 
-	newinfo->entries = vmalloc(tmp.entries_size);
+	newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT,
+				     PAGE_KERNEL);
 	if (!newinfo->entries) {
 		ret = -ENOMEM;
 		goto free_newinfo;