[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 32.173279] random: sshd: uninitialized urandom read (32 bytes read) [ 32.455655] kauditd_printk_skb: 10 callbacks suppressed [ 32.455664] audit: type=1400 audit(1575378415.678:35): avc: denied { map } for pid=7064 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 [ 32.524988] random: sshd: uninitialized urandom read (32 bytes read) [ 33.061448] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 36.707266] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.231' (ECDSA) to the list of known hosts. [ 42.218561] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 42.340302] audit: type=1400 audit(1575378425.568:36): avc: denied { map } for pid=7077 comm="syz-executor250" path="/root/syz-executor250097564" 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 executing program [ 42.409999] ================================================================== [ 42.417602] BUG: KASAN: use-after-free in tty_open+0x995/0xa10 [ 42.423568] Read of size 8 at addr ffff88807555e480 by task syz-executor250/7091 [ 42.431086] [ 42.432727] CPU: 1 PID: 7091 Comm: syz-executor250 Not tainted 4.14.157-syzkaller #0 [ 42.440776] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.450120] Call Trace: [ 42.452717] dump_stack+0x142/0x197 [ 42.456506] ? tty_open+0x995/0xa10 [ 42.460119] print_address_description.cold+0x7c/0x1dc [ 42.465379] ? tty_open+0x995/0xa10 [ 42.468991] kasan_report.cold+0xa9/0x2af [ 42.473131] __asan_report_load8_noabort+0x14/0x20 [ 42.478040] tty_open+0x995/0xa10 [ 42.481476] ? tty_init_dev+0x3a0/0x3a0 [ 42.485444] ? do_raw_spin_unlock+0x16b/0x260 [ 42.489921] ? tty_init_dev+0x3a0/0x3a0 [ 42.493878] chrdev_open+0x207/0x590 [ 42.497573] ? cdev_put.part.0+0x50/0x50 [ 42.501626] ? security_file_open+0x89/0x190 [ 42.506018] do_dentry_open+0x73b/0xeb0 [ 42.510063] ? cdev_put.part.0+0x50/0x50 [ 42.514115] vfs_open+0x105/0x220 [ 42.517576] path_openat+0x8bd/0x3f70 [ 42.521391] ? trace_hardirqs_on+0x10/0x10 [ 42.525623] ? path_lookupat.isra.0+0x7b0/0x7b0 [ 42.530399] ? find_held_lock+0x35/0x130 [ 42.534458] ? __alloc_fd+0x1d4/0x4a0 [ 42.538247] do_filp_open+0x18e/0x250 [ 42.542036] ? may_open_dev+0xe0/0xe0 [ 42.545840] ? do_raw_spin_unlock+0x16b/0x260 [ 42.550320] ? _raw_spin_unlock+0x2d/0x50 [ 42.554538] ? __alloc_fd+0x1d4/0x4a0 [ 42.558325] do_sys_open+0x2c5/0x430 [ 42.562022] ? filp_open+0x70/0x70 [ 42.565546] ? security_file_ioctl+0x89/0xb0 [ 42.569939] SyS_open+0x2d/0x40 [ 42.573201] ? do_sys_open+0x430/0x430 [ 42.577069] do_syscall_64+0x1e8/0x640 [ 42.580949] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.585791] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.590967] RIP: 0033:0x401140 [ 42.594142] RSP: 002b:00007fff817f6a78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 42.601840] RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000401140 [ 42.609100] RDX: 0000000000000000 RSI: 0000000000127200 RDI: 00007fff817f6aa0 [ 42.616353] RBP: 000000000000a57f R08: 000000000000000f R09: 00000000004002e0 [ 42.623612] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402160 [ 42.630881] R13: 00000000004021f0 R14: 0000000000000000 R15: 0000000000000000 [ 42.638157] [ 42.639773] Allocated by task 7086: [ 42.643383] save_stack_trace+0x16/0x20 [ 42.647357] save_stack+0x45/0xd0 [ 42.650804] kasan_kmalloc+0xce/0xf0 [ 42.654504] kmem_cache_alloc_trace+0x152/0x790 [ 42.659156] vc_allocate+0x148/0x580 [ 42.662882] con_install+0x52/0x400 [ 42.666490] tty_init_dev+0xea/0x3a0 [ 42.670195] tty_open+0x414/0xa10 [ 42.673639] chrdev_open+0x207/0x590 [ 42.677339] do_dentry_open+0x73b/0xeb0 [ 42.681298] vfs_open+0x105/0x220 [ 42.684994] path_openat+0x8bd/0x3f70 [ 42.688791] do_filp_open+0x18e/0x250 [ 42.692836] do_sys_open+0x2c5/0x430 [ 42.696532] SyS_open+0x2d/0x40 [ 42.699795] do_syscall_64+0x1e8/0x640 [ 42.703663] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.708828] [ 42.710437] Freed by task 7091: [ 42.713696] save_stack_trace+0x16/0x20 [ 42.717650] save_stack+0x45/0xd0 [ 42.721085] kasan_slab_free+0x75/0xc0 [ 42.724964] kfree+0xcc/0x270 [ 42.728055] vt_disallocate_all+0x286/0x380 [ 42.732364] vt_ioctl+0x76b/0x2170 [ 42.735905] tty_ioctl+0x841/0x1320 [ 42.739562] do_vfs_ioctl+0x7ae/0x1060 [ 42.743431] SyS_ioctl+0x8f/0xc0 [ 42.746788] do_syscall_64+0x1e8/0x640 [ 42.750666] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.755840] [ 42.757452] The buggy address belongs to the object at ffff88807555e280 [ 42.757452] which belongs to the cache kmalloc-2048 of size 2048 [ 42.770259] The buggy address is located 512 bytes inside of [ 42.770259] 2048-byte region [ffff88807555e280, ffff88807555ea80) [ 42.782208] The buggy address belongs to the page: [ 42.787235] page:ffffea0001d55780 count:1 mapcount:0 mapping:ffff88807555e280 index:0x0 compound_mapcount: 0 [ 42.797300] flags: 0xfffe0000008100(slab|head) [ 42.801869] raw: 00fffe0000008100 ffff88807555e280 0000000000000000 0000000100000003 [ 42.809732] raw: ffffea000233b5a0 ffffea0002a17720 ffff8880aa800c40 0000000000000000 [ 42.817594] page dumped because: kasan: bad access detected [ 42.823285] [ 42.824891] Memory state around the buggy address: [ 42.829799] ffff88807555e380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.837141] ffff88807555e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.844493] >ffff88807555e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.851832] ^ [ 42.855179] ffff88807555e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.862518] ffff88807555e580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.869858] ================================================================== [ 42.877195] Disabling lock debugging due to kernel taint [ 42.883849] Kernel panic - not syncing: panic_on_warn set ... [ 42.883849] [ 42.891227] CPU: 1 PID: 7091 Comm: syz-executor250 Tainted: G B 4.14.157-syzkaller #0 [ 42.900304] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.909639] Call Trace: [ 42.912212] dump_stack+0x142/0x197 [ 42.915821] ? tty_open+0x995/0xa10 [ 42.919428] panic+0x1f9/0x42d [ 42.922602] ? add_taint.cold+0x16/0x16 [ 42.926646] ? ___preempt_schedule+0x16/0x18 [ 42.931048] kasan_end_report+0x47/0x4f [ 42.935014] kasan_report.cold+0x130/0x2af [ 42.939229] __asan_report_load8_noabort+0x14/0x20 [ 42.944136] tty_open+0x995/0xa10 [ 42.947575] ? tty_init_dev+0x3a0/0x3a0 [ 42.951534] ? do_raw_spin_unlock+0x16b/0x260 [ 42.956012] ? tty_init_dev+0x3a0/0x3a0 [ 42.959968] chrdev_open+0x207/0x590 [ 42.963752] ? cdev_put.part.0+0x50/0x50 [ 42.967807] ? security_file_open+0x89/0x190 [ 42.972215] do_dentry_open+0x73b/0xeb0 [ 42.976169] ? cdev_put.part.0+0x50/0x50 [ 42.980208] vfs_open+0x105/0x220 [ 42.983641] path_openat+0x8bd/0x3f70 [ 42.987429] ? trace_hardirqs_on+0x10/0x10 [ 42.991655] ? path_lookupat.isra.0+0x7b0/0x7b0 [ 42.996306] ? find_held_lock+0x35/0x130 [ 43.000352] ? __alloc_fd+0x1d4/0x4a0 [ 43.004135] do_filp_open+0x18e/0x250 [ 43.007914] ? may_open_dev+0xe0/0xe0 [ 43.011697] ? do_raw_spin_unlock+0x16b/0x260 [ 43.016185] ? _raw_spin_unlock+0x2d/0x50 [ 43.020675] ? __alloc_fd+0x1d4/0x4a0 [ 43.024467] do_sys_open+0x2c5/0x430 [ 43.028166] ? filp_open+0x70/0x70 [ 43.031704] ? security_file_ioctl+0x89/0xb0 [ 43.036123] SyS_open+0x2d/0x40 [ 43.039392] ? do_sys_open+0x430/0x430 [ 43.043265] do_syscall_64+0x1e8/0x640 [ 43.047133] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 43.051963] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 43.057132] RIP: 0033:0x401140 [ 43.060301] RSP: 002b:00007fff817f6a78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 43.068252] RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000401140 [ 43.075502] RDX: 0000000000000000 RSI: 0000000000127200 RDI: 00007fff817f6aa0 [ 43.082752] RBP: 000000000000a57f R08: 000000000000000f R09: 00000000004002e0 [ 43.089999] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402160 [ 43.097269] R13: 00000000004021f0 R14: 0000000000000000 R15: 0000000000000000 [ 43.105955] Kernel Offset: disabled [ 43.109627] Rebooting in 86400 seconds..