Shakeel Butt
2018-Dec-29 01:55 UTC
[Bridge] [PATCH] netfilter: account ebt_table_info to kmemcg
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>
---
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 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;
--
2.20.1.415.g653613c723-goog
Michal Hocko
2018-Dec-29 07:33 UTC
[Bridge] [PATCH] netfilter: account ebt_table_info to kmemcg
On Fri 28-12-18 17:55:24, Shakeel Butt wrote:> 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.What is the lifetime of these objects? Are they bound to any process?> Reported-by: syzbot+7713f3aa67be76b1552c at syzkaller.appspotmail.com > Signed-off-by: Shakeel Butt <shakeelb at google.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 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; > -- > 2.20.1.415.g653613c723-goog >-- Michal Hocko SUSE Labs
Florian Westphal
2018-Dec-29 09:52 UTC
[Bridge] [PATCH] netfilter: account ebt_table_info to kmemcg
Michal Hocko <mhocko at kernel.org> wrote:> On Fri 28-12-18 17:55:24, Shakeel Butt wrote: > > 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. > > What is the lifetime of these objects? Are they bound to any process?No, they are not. They are free'd only when userspace requests it or the netns is destroyed.