On Wed, 2017-11-29 at 21:26 +1100, James Morris wrote: > I'm seeing a kernel stack corruption bug (detected via gcc) when > running > the SELinux testsuite on a 4.15-rc1 kernel, in the 2nd inet_socket > test: > > https://github.com/SELinuxProject/selinux-testsuite/blob/master/tests > /inet_socket/test > > # Verify that unauthorized client cannot communicate with the > server. > $result = system > "runcon -t test_inet_bad_client_t -- $basedir/client stream > 127.0.0.1 65535 2>&1"; > > This correctlly causes an access control error in the Netlabel code, > and > the bug seems to be triggered during the ICMP send: > > [ 339.806024] SELinux: failure in selinux_parse_skb(), unable to > parse packet > [ 339.822505] Kernel panic - not syncing: stack-protector: Kernel > stack is corrupted in: ffffffff81745af5 > [ 339.822505] > [ 339.852250] CPU: 4 PID: 3642 Comm: client Not tainted 4.15.0-rc1- > test #15 > [ 339.868498] Hardware name: LENOVO 10FGS0VA1L/30BC, BIOS > FWKT68A 01/19/2017 > [ 339.885060] Call Trace: > [ 339.896875] <IRQ> > [ 339.908103] dump_stack+0x63/0x87 > [ 339.920645] panic+0xe8/0x248 > [ 339.932668] ? ip_push_pending_frames+0x33/0x40 > [ 339.946328] ? icmp_send+0x525/0x530 > [ 339.958861] ? kfree_skbmem+0x60/0x70 > [ 339.971431] __stack_chk_fail+0x1b/0x20 > [ 339.984049] icmp_send+0x525/0x530 > [ 339.996205] ? netlbl_skbuff_err+0x36/0x40 > [ 340.008997] ? selinux_netlbl_err+0x11/0x20 > [ 340.021816] ? selinux_socket_sock_rcv_skb+0x211/0x230 > [ 340.035529] ? security_sock_rcv_skb+0x3b/0x50 > [ 340.048471] ? sk_filter_trim_cap+0x44/0x1c0 > [ 340.061246] ? tcp_v4_inbound_md5_hash+0x69/0x1b0 > [ 340.074562] ? tcp_filter+0x2c/0x40 > [ 340.086400] ? tcp_v4_rcv+0x820/0xa20 > [ 340.098329] ? ip_local_deliver_finish+0x71/0x1a0 > [ 340.111279] ? ip_local_deliver+0x6f/0xe0 > [ 340.123535] ? ip_rcv_finish+0x3a0/0x3a0 > [ 340.135523] ? ip_rcv_finish+0xdb/0x3a0 > [ 340.147442] ? ip_rcv+0x27c/0x3c0 > [ 340.158668] ? inet_del_offload+0x40/0x40 > [ 340.170580] ? __netif_receive_skb_core+0x4ac/0x900 > [ 340.183285] ? rcu_accelerate_cbs+0x5b/0x80 > [ 340.195282] ? __netif_receive_skb+0x18/0x60 > [ 340.207288] ? process_backlog+0x95/0x140 > [ 340.218948] ? net_rx_action+0x26c/0x3b0 > [ 340.230416] ? __do_softirq+0xc9/0x26a > [ 340.241625] ? do_softirq_own_stack+0x2a/0x40 > [ 340.253368] </IRQ> > [ 340.262673] ? do_softirq+0x50/0x60 > [ 340.273450] ? __local_bh_enable_ip+0x57/0x60 > [ 340.285045] ? ip_finish_output2+0x175/0x350 > [ 340.296403] ? ip_finish_output+0x127/0x1d0 > [ 340.307665] ? nf_hook_slow+0x3c/0xb0 > [ 340.318230] ? ip_output+0x72/0xe0 > [ 340.328524] ? ip_fragment.constprop.54+0x80/0x80 > [ 340.340070] ? ip_local_out+0x35/0x40 > [ 340.350497] ? ip_queue_xmit+0x15c/0x3f0 > [ 340.361060] ? __kmalloc_reserve.isra.40+0x31/0x90 > [ 340.372484] ? __skb_clone+0x2e/0x130 > [ 340.382633] ? tcp_transmit_skb+0x558/0xa10 > [ 340.393262] ? tcp_connect+0x938/0xad0 > [ 340.403370] ? ktime_get_with_offset+0x4c/0xb0 > [ 340.414206] ? tcp_v4_connect+0x457/0x4e0 > [ 340.424471] ? __inet_stream_connect+0xb3/0x300 > [ 340.435195] ? inet_stream_connect+0x3b/0x60 > [ 340.445607] ? SYSC_connect+0xd9/0x110 > [ 340.455455] ? __audit_syscall_entry+0xaf/0x100 > [ 340.466112] ? syscall_trace_enter+0x1d0/0x2b0 > [ 340.476636] ? __audit_syscall_exit+0x209/0x290 > [ 340.487151] ? SyS_connect+0xe/0x10 > [ 340.496453] ? do_syscall_64+0x67/0x1b0 > [ 340.506078] ? entry_SYSCALL64_slow_path+0x25/0x25 > [ 340.516693] Kernel Offset: disabled > [ 340.526393] Rebooting in 11 seconds.. > > This is mostly reliable, and I'm only seeing it on bare metal (not in > a > virtualbox vm). > > The SELinux skb parse error at the start only sometimes appears, and > looking at the code, I suspect some kind of memory corruption being > the > cause at that point (basic packet header checks). > > I bisected the bug down to the following change: > > commit bffa72cf7f9df842f0016ba03586039296b4caaf > Author: Eric Dumazet <edumazet@xxxxxxxxxx> > Date: Tue Sep 19 05:14:24 2017 -0700 > > net: sk_buff rbnode reorg > ... > > > Anyone else able to reproduce this, or have any ideas on what's > happening? So far I haven't been able to reproduce with 4.15-rc1 or -linus.
