Messages in this thread | | | From | Cong Wang <> | Date | Wed, 1 Aug 2018 22:23:42 -0700 | Subject | Re: KASAN: use-after-free Read in rtnetlink_put_metrics |
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On Wed, Aug 1, 2018 at 1:15 AM Sabrina Dubroca <sd@queasysnail.net> wrote: > > 2018-07-31, 16:03:13 -0700, Cong Wang wrote: > > On Tue, Jul 31, 2018 at 6:41 AM Sabrina Dubroca <sd@queasysnail.net> wrote: > > > > > > 2018-07-31, 05:41:56 -0700, Eric Dumazet wrote: > > > > > > > > > > > > On 07/31/2018 05:31 AM, syzbot wrote: > > > > > Hello, > > > > > > > > > > syzbot found the following crash on: > > > > > > > > > > HEAD commit: 61f4b23769f0 netlink: Don't shift with UB on nlk->ngroups > > > > > git tree: net > > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=14a9de58400000 > > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=ffb4428fdc82f93b > > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=41f9c04b50ef70c66947 > > > > > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > > > > > > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > [...] > > > > > > > Probably also caused by : > > > > > > > > > > > > commit df18b50448fab1dff093731dfd0e25e77e1afcd1 > > > > Author: Sabrina Dubroca <sd@queasysnail.net> > > > > Date: Mon Jul 30 16:23:10 2018 +0200 > > > > > > > > net/ipv6: fix metrics leak > > > > > > Yeah, I'm looking into both those reports :/ > > > > Looks like this commit is completely unnecessary, > > fib6_drop_pcpu_from() calls fib6_info_release() > > which calls fib6_info_destroy_rcu(), so this metrics > > will be released twice... > > kmemleak disagrees:
This information is missing from changelog. :)
> > unreferenced object 0xffff88006b605080 (size 96): > comm "ip", pid 433, jiffies 4294889793 (age 74.844s) > hex dump (first 32 bytes): > 00 00 00 00 f4 01 00 00 00 00 00 00 00 00 00 00 ................ > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > backtrace: > [<000000002650e4e2>] ip6_route_info_create+0x770/0x4050 > [<000000000a8d4c52>] ip6_route_add+0x18/0x90 > [<00000000474d669c>] inet6_rtm_newroute+0xeb/0x100 > [<0000000019fb732d>] rtnetlink_rcv_msg+0x3b5/0xb40 > [<000000006f891e19>] netlink_rcv_skb+0x137/0x380 > [<0000000070451985>] netlink_unicast+0x47f/0x6e0 > [<000000004487d656>] netlink_sendmsg+0x7a7/0x10c0 > [<0000000089fdf5ae>] sock_sendmsg+0xac/0x160 > [<00000000aae19c54>] ___sys_sendmsg+0x6e0/0xbb0 > [<00000000a3906352>] __sys_sendmsg+0xdc/0x230 > [<00000000c7c8548a>] do_syscall_64+0x15d/0x740 > [<000000007dfdad73>] entry_SYSCALL_64_after_hwframe+0x49/0xbe > [<000000003adb705a>] 0xffffffffffffffff
My kernel dev machine is broken now. I will take a look tomorrow after I fix my kernel dev machine.
Thanks!
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