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authorShakeel Butt <shakeelb@google.com>2019-01-02 19:14:31 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-22 21:40:35 +0100
commit2663bcba075f4faec98aee7b24bf11aa748316b3 (patch)
tree60928ec99241e5ebba95e55a3934478cdef5f7df
parent61b29bed90103d1a0fc052fb15027c33cee551f8 (diff)
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netfilter: ebtables: account ebt_table_info to kmemcg
commit e2c8d550a973bb34fc28bc8d0ec996f84562fb8a upstream. 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. By accounting the ebt_table_info, the memory used for ebt_table_info can be contained within the memcg of the allocating process. However the lifetime of ebt_table_info is independent of the allocating process and is tied to the network namespace. So, the oom-killer will not be able to relieve the memory pressure due to ebt_table_info memory. The memory for ebt_table_info is allocated through vmalloc. Currently vmalloc does not handle the oom-killed allocating process correctly and one large allocation can bypass memcg limit enforcement. So, with this patch, at least the small allocations will be contained. For large allocations, we need to fix vmalloc. Reported-by: syzbot+7713f3aa67be76b1552c@syzkaller.appspotmail.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/bridge/netfilter/ebtables.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 491828713e0b..5e55cef0cec3 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1137,14 +1137,16 @@ 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;