[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 35.463410] random: sshd: uninitialized urandom read (32 bytes read) [ 35.769648] kauditd_printk_skb: 10 callbacks suppressed [ 35.769656] audit: type=1400 audit(1581961800.841:35): avc: denied { map } for pid=7249 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 [ 35.822323] random: sshd: uninitialized urandom read (32 bytes read) [ 36.536766] random: sshd: uninitialized urandom read (32 bytes read) [ 36.730447] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.143' (ECDSA) to the list of known hosts. [ 42.285919] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program [ 42.402112] audit: type=1400 audit(1581961807.481:36): avc: denied { map } for pid=7261 comm="syz-executor607" path="/root/syz-executor607211838" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 42.470530] ================================================================== [ 42.470560] BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 [ 42.470567] Write of size 8 at addr ffff8880a48ff808 by task syz-executor607/7269 [ 42.470569] [ 42.470578] CPU: 1 PID: 7269 Comm: syz-executor607 Not tainted 4.14.171-syzkaller #0 [ 42.470583] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.470586] Call Trace: [ 42.470598] dump_stack+0x142/0x197 [ 42.470608] ? con_shutdown+0x85/0x90 [ 42.470619] print_address_description.cold+0x7c/0x1dc [ 42.470628] ? con_shutdown+0x85/0x90 [ 42.470635] kasan_report.cold+0xa9/0x2af [ 42.470643] ? set_palette+0x140/0x140 [ 42.470653] __asan_report_store8_noabort+0x17/0x20 [ 42.470660] con_shutdown+0x85/0x90 [ 42.470668] release_tty+0xbf/0x7c0 [ 42.470678] tty_release_struct+0x3c/0x50 [ 42.470685] tty_release+0xaa3/0xd60 [ 42.470698] ? tty_release_struct+0x50/0x50 [ 42.470706] __fput+0x275/0x7a0 [ 42.470719] ____fput+0x16/0x20 [ 42.470728] task_work_run+0x114/0x190 [ 42.470738] do_exit+0xa1a/0x2cd0 [ 42.470748] ? mm_update_next_owner+0x5d0/0x5d0 [ 42.470758] ? up_read+0x1a/0x40 [ 42.470763] ? __do_page_fault+0x358/0xb80 [ 42.470773] do_group_exit+0x111/0x330 [ 42.470781] SyS_exit_group+0x1d/0x20 [ 42.470786] ? do_group_exit+0x330/0x330 [ 42.470793] do_syscall_64+0x1e8/0x640 [ 42.470799] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.470812] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.470819] RIP: 0033:0x43ff38 [ 42.470824] RSP: 002b:00007ffdf939d488 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 42.470832] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 42.470836] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 42.470839] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 42.470842] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 42.470845] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 42.470855] [ 42.470858] Allocated by task 7269: [ 42.470865] save_stack_trace+0x16/0x20 [ 42.470869] save_stack+0x45/0xd0 [ 42.470873] kasan_kmalloc+0xce/0xf0 [ 42.470878] kmem_cache_alloc_trace+0x152/0x790 [ 42.470883] vc_allocate+0x148/0x580 [ 42.470887] con_install+0x52/0x400 [ 42.470892] tty_init_dev+0xea/0x3a0 [ 42.470896] tty_open+0x414/0xa10 [ 42.470901] chrdev_open+0x207/0x590 [ 42.470907] do_dentry_open+0x73b/0xeb0 [ 42.470911] vfs_open+0x105/0x220 [ 42.470916] path_openat+0x917/0x3e50 [ 42.470920] do_filp_open+0x18e/0x250 [ 42.470925] do_sys_open+0x2c5/0x430 [ 42.470929] SyS_open+0x2d/0x40 [ 42.470934] do_syscall_64+0x1e8/0x640 [ 42.470939] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.470940] [ 42.470943] Freed by task 7274: [ 42.470947] save_stack_trace+0x16/0x20 [ 42.470951] save_stack+0x45/0xd0 [ 42.470955] kasan_slab_free+0x75/0xc0 [ 42.470959] kfree+0xcc/0x270 [ 42.470963] vt_disallocate_all+0x286/0x380 [ 42.470967] vt_ioctl+0x76b/0x2170 [ 42.470971] tty_ioctl+0x841/0x1320 [ 42.470977] do_vfs_ioctl+0x7ae/0x1060 [ 42.470981] SyS_ioctl+0x8f/0xc0 [ 42.470986] do_syscall_64+0x1e8/0x640 [ 42.470991] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.470992] [ 42.470996] The buggy address belongs to the object at ffff8880a48ff700 [ 42.470996] which belongs to the cache kmalloc-2048 of size 2048 [ 42.471001] The buggy address is located 264 bytes inside of [ 42.471001] 2048-byte region [ffff8880a48ff700, ffff8880a48fff00) [ 42.471003] The buggy address belongs to the page: [ 42.471007] page:ffffea0002923f80 count:1 mapcount:0 mapping:ffff8880a48fe600 index:0x0 compound_mapcount: 0 [ 42.471015] flags: 0xfffe0000008100(slab|head) [ 42.471023] raw: 00fffe0000008100 ffff8880a48fe600 0000000000000000 0000000100000003 [ 42.471029] raw: ffffea000209b0a0 ffffea0002933c20 ffff8880aa800c40 0000000000000000 [ 42.471031] page dumped because: kasan: bad access detected [ 42.471033] [ 42.471034] Memory state around the buggy address: [ 42.471039] ffff8880a48ff700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.471043] ffff8880a48ff780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.471047] >ffff8880a48ff800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.471049] ^ [ 42.471053] ffff8880a48ff880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.471057] ffff8880a48ff900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.471059] ================================================================== [ 42.471061] Disabling lock debugging due to kernel taint [ 42.471082] Kernel panic - not syncing: panic_on_warn set ... [ 42.471082] [ 42.471087] CPU: 1 PID: 7269 Comm: syz-executor607 Tainted: G B 4.14.171-syzkaller #0 [ 42.471090] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.471091] Call Trace: [ 42.471096] dump_stack+0x142/0x197 [ 42.471102] ? con_shutdown+0x85/0x90 [ 42.471106] panic+0x1f9/0x42d [ 42.471111] ? add_taint.cold+0x16/0x16 [ 42.471119] kasan_end_report+0x47/0x4f [ 42.471124] kasan_report.cold+0x130/0x2af [ 42.471128] ? set_palette+0x140/0x140 [ 42.471139] __asan_report_store8_noabort+0x17/0x20 [ 42.471144] con_shutdown+0x85/0x90 [ 42.471148] release_tty+0xbf/0x7c0 [ 42.471154] tty_release_struct+0x3c/0x50 [ 42.471159] tty_release+0xaa3/0xd60 [ 42.471167] ? tty_release_struct+0x50/0x50 [ 42.471170] __fput+0x275/0x7a0 [ 42.471177] ____fput+0x16/0x20 [ 42.471182] task_work_run+0x114/0x190 [ 42.471188] do_exit+0xa1a/0x2cd0 [ 42.471195] ? mm_update_next_owner+0x5d0/0x5d0 [ 42.471201] ? up_read+0x1a/0x40 [ 42.471205] ? __do_page_fault+0x358/0xb80 [ 42.471210] do_group_exit+0x111/0x330 [ 42.471216] SyS_exit_group+0x1d/0x20 [ 42.471220] ? do_group_exit+0x330/0x330 [ 42.471225] do_syscall_64+0x1e8/0x640 [ 42.471230] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.471236] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.471239] RIP: 0033:0x43ff38 [ 42.471242] RSP: 002b:00007ffdf939d488 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 42.471247] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 42.471250] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 42.471253] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 42.471255] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 42.471258] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 42.472749] Kernel Offset: disabled [ 43.094299] Rebooting in 86400 seconds..