Re: KASAN: use-after-free Read in tomoyo_socket_sendmsg_permission
From: Tetsuo Handa
Date: Thu Aug 08 2019 - 18:08:24 EST
On 2019/08/09 1:45, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 107e47cc vrf: make sure skb->data contains ip header to ma..
> git tree: net
> console output: https://syzkaller.appspot.com/x/log.txt?x=139506d8600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=4dba67bf8b8c9ad7
> dashboard link: https://syzkaller.appspot.com/bug?extid=b91501546ab4037f685f
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
This is not TOMOYO's bug. LSM modules expect that "struct sock" does not go away.
Also, another use-after-free (presumably on the same "struct sock") was concurrently
inflight at nr_insert_socket() in net/netrom/af_netrom.c . Thus, suspecting netrom's bug.
[ 625.441058][ C0] ------------[ cut here ]------------
[ 625.446837][ C0] refcount_t: increment on 0; use-after-free.
[ 625.461518][ C0] WARNING: CPU: 0 PID: 0 at lib/refcount.c:156 refcount_inc_checked+0x61/0x70
[ 625.479173][ C0] Kernel panic - not syncing: panic_on_warn set ...
[ 625.746558][ C0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.2.0+ #97
[ 625.746575][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 625.755731][ C0] Call Trace:
[ 625.770091][ C0] <IRQ>
[ 625.777543][ C0] dump_stack+0x172/0x1f0
[ 625.786005][ C0] ? refcount_inc_not_zero_checked+0x1f0/0x200
[ 625.794831][ C0] panic+0x2dc/0x755
[ 625.805217][ C0] ? add_taint.cold+0x16/0x16
[ 625.813697][ C0] ? __kasan_check_write+0x14/0x20
[ 625.822433][ C0] ? __warn.cold+0x5/0x4c
[ 625.832388][ C0] ? __warn+0xe7/0x1e0
[ 625.841820][ C0] ? refcount_inc_checked+0x61/0x70
[ 625.851148][ C0] __warn.cold+0x20/0x4c
[ 625.859701][ C0] ? vprintk_emit+0x1ea/0x700
[ 625.867208][ C0] ? refcount_inc_checked+0x61/0x70
[ 625.875413][ C0] report_bug+0x263/0x2b0
[ 625.884580][ C0] do_error_trap+0x11b/0x200
[ 625.893730][ C0] do_invalid_op+0x37/0x50
[ 625.902936][ C0] ? refcount_inc_checked+0x61/0x70
[ 625.911858][ C0] invalid_op+0x14/0x20
[ 625.920825][ C0] RIP: 0010:refcount_inc_checked+0x61/0x70
[ 625.929407][ C0] Code: 1d 3f 6e 64 06 31 ff 89 de e8 cb d2 35 fe 84 db 75 dd e8 82 d1 35 fe 48 c7 c7 40 09 c6 87 c6 05 1f 6e 64 06 01 e8 77 39 07 fe <0f> 0b eb c1 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41
[ 625.937608][ C0] RSP: 0018:ffff8880ae809bf0 EFLAGS: 00010282
[ 625.948510][ C0] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 625.957237][ C0] RDX: 0000000000000100 RSI: ffffffff815c3a26 RDI: ffffed1015d01370
[ 625.967249][ C0] RBP: ffff8880ae809c00 R08: ffffffff88c7a1c0 R09: fffffbfff14a775b
[ 625.991542][ C0] R10: fffffbfff14a775a R11: ffffffff8a53bad7 R12: ffff8880a066f480
[ 626.002193][ C0] R13: ffff8880a066f468 R14: ffff88808d69ef48 R15: ffff88808d69ef20
[ 626.014844][ C0] ? vprintk_func+0x86/0x189
[ 626.027298][ C0] nr_insert_socket+0x2d/0xe0
[ 626.041237][ C0] nr_rx_frame+0x1605/0x1e73
[ 626.051737][ C0] nr_loopback_timer+0x7b/0x170
[ 626.073842][ C0] call_timer_fn+0x1ac/0x780
[ 626.092970][ C0] ? nr_process_rx_frame+0x1540/0x1540
[ 626.108552][ C0] ? msleep_interruptible+0x150/0x150
[ 626.118574][ C0] ? run_timer_softirq+0x685/0x17a0
[ 626.131811][ C0] ? trace_hardirqs_on+0x67/0x240
[ 626.145424][ C0] ? __kasan_check_read+0x11/0x20
[ 626.156592][ C0] ? nr_process_rx_frame+0x1540/0x1540
[ 626.164362][ C0] ? nr_process_rx_frame+0x1540/0x1540
[ 626.175423][ C0] run_timer_softirq+0x697/0x17a0
[ 626.188804][ C0] ? add_timer+0x930/0x930
[ 626.202652][ C0] ? kvm_clock_read+0x18/0x30
[ 626.215813][ C0] ? kvm_sched_clock_read+0x9/0x20
[ 626.231378][ C0] ? sched_clock+0x2e/0x50
[ 626.231395][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 626.231408][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 626.231432][ C0] __do_softirq+0x262/0x98c
[ 626.244512][ C0] ? sched_clock_cpu+0x1b/0x1b0
[ 626.244531][ C0] irq_exit+0x19b/0x1e0
[ 626.244545][ C0] smp_apic_timer_interrupt+0x1a3/0x610
[ 626.244558][ C0] apic_timer_interrupt+0xf/0x20
[ 626.244563][ C0] </IRQ>
[ 626.244579][ C0] RIP: 0010:native_safe_halt+0xe/0x10
[ 626.244606][ C0] Code: b8 94 73 fa eb 8a 90 90 90 90 90 90 e9 07 00 00 00 0f 00 2d 34 25 4f 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 24 25 4f 00 fb f4 <c3> 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 0e 56 27 fa e8 c9
[ 626.257081][ C0] RSP: 0018:ffffffff88c07ce8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
[ 626.269812][ C0] RAX: 1ffffffff11a5e05 RBX: ffffffff88c7a1c0 RCX: 0000000000000000
[ 626.281053][ C0] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff88c7aa4c
[ 626.290913][ C0] RBP: ffffffff88c07d18 R08: ffffffff88c7a1c0 R09: 0000000000000000
[ 626.303361][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
[ 626.314081][ C0] R13: ffffffff89a4f778 R14: 0000000000000000 R15: 0000000000000000
[ 626.314116][ C0] ? default_idle+0x4e/0x360
[ 626.323075][ C0] arch_cpu_idle+0xa/0x10
[ 626.333543][ C0] default_idle_call+0x84/0xb0
[ 626.341839][ C0] do_idle+0x413/0x760
[ 626.370736][ C0] ? retint_kernel+0x2b/0x2b
[ 626.383044][ C0] ? arch_cpu_idle_exit+0x80/0x80
[ 626.400071][ C0] ? do_idle+0x387/0x760
[ 626.418085][ C0] cpu_startup_entry+0x1b/0x20
[ 626.431835][ C0] rest_init+0x245/0x37b
[ 626.459420][ C0] arch_call_rest_init+0xe/0x1b
[ 626.471993][ C0] start_kernel+0x912/0x951
[ 626.482387][ C0] ? mem_encrypt_init+0xb/0xb
[ 626.495105][ C0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[ 626.507125][ C0] ? x86_family+0x41/0x50
[ 626.519773][ C0] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20
[ 626.532837][ C0] x86_64_start_reservations+0x29/0x2b
[ 626.545019][ C0] x86_64_start_kernel+0x77/0x7b
[ 626.558711][ C0] secondary_startup_64+0xa4/0xb0
[ 626.897092][ C0] Kernel Offset: disabled
[ 626.901428][ C0] Rebooting in 86400 seconds..