From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Smalley Subject: Re: [BUG] kernel stack corruption during/after Netlabel error Date: Wed, 29 Nov 2017 12:31:46 -0500 Message-ID: <1511976706.10464.19.camel@tycho.nsa.gov> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Cc: netdev@vger.kernel.org, selinux@tycho.nsa.gov To: James Morris , Paul Moore , Eric Dumazet Return-path: Received: from upbd19pa07.eemsg.mail.mil ([214.24.27.82]:55911 "EHLO upbd19pa07.eemsg.mail.mil" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933812AbdK2RbW (ORCPT ); Wed, 29 Nov 2017 12:31:22 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: 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]   > [  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]   > [  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 > 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.