On Wed, Jan 3, 2018 at 8:37 AM, Andrei Vagin <ava...@virtuozzo.com> wrote: >> > Hello, >> > >> > syzkaller hit the following crash on >> > 75aa5540627fdb3d8f86229776ea87f995275351 >> > git://git.cmpxchg.org/linux-mmots.git/master >> > compiler: gcc (GCC) 7.1.1 20170620 >> > .config is attached >> > Raw console output is attached. >> > C reproducer is attached >> > syzkaller reproducer is attached. See https://goo.gl/kgGztJ >> > for information about syzkaller reproducers >> > >> > >> > IMPORTANT: if you fix the bug, please add the following tag to the commit: >> > Reported-by: syzbot+e432865c29eb4c48c...@syzkaller.appspotmail.com >> > It will help syzbot understand when the bug is fixed. See footer for >> > details. >> > If you forward the report, please keep this part and the footer. >> > >> > netlink: 3 bytes leftover after parsing attributes in process >> > `syzkaller140561'. >> > netlink: 3 bytes leftover after parsing attributes in process >> > `syzkaller140561'. >> > netlink: 3 bytes leftover after parsing attributes in process >> > `syzkaller140561'. >> > kasan: CONFIG_KASAN_INLINE enabled >> > kasan: GPF could be caused by NULL-ptr deref or user memory access >> > general protection fault: 0000 [#1] SMP KASAN >> > Dumping ftrace buffer: >> > (ftrace buffer empty) >> > Modules linked in: >> > CPU: 1 PID: 3149 Comm: syzkaller140561 Not tainted 4.15.0-rc4-mm1+ #47 >> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> > Google 01/01/2011 >> > RIP: 0010:__netlink_ns_capable+0x8b/0x120 net/netlink/af_netlink.c:868 >> >> NETLINK_CB(skb).sk is NULL here. It looks like we have to use >> sk_ns_capable instead of netlink_ns_capable: >> >> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c >> index c688dc564b11..408c75de52ea 100644 >> --- a/net/core/rtnetlink.c >> +++ b/net/core/rtnetlink.c >> @@ -1762,7 +1762,7 @@ static struct net *get_target_net(struct sk_buff >> *skb, int netnsid) >> /* For now, the caller is required to have CAP_NET_ADMIN in >> * the user namespace owning the target net ns. >> */ >> - if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) { >> + if (!sk_ns_capable(skb->sk, net->user_ns, CAP_NET_ADMIN)) { >> put_net(net); >> return ERR_PTR(-EACCES); >> } >> > > get_target_net() is used twice in the code. In rtnl_getlink(), we need > to use netlink_ns_capable(skb, ...), but in rtnl_dump_ifinfo, we need to > use sk_ns_capable(skb->sk, ...). > > Pls, take a look at this patch: > https://patchwork.ozlabs.org/patch/854896/ > Subject: rtnetlink: give a user socket to get_target_net()
Please include this tag into the commit: > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+e432865c29eb4c48c...@syzkaller.appspotmail.com > > It will help syzbot understand when the bug is fixed.
