5l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 39.000792] random: sshd: uninitialized urandom read (32 bytes read) [ 39.367395] audit: type=1400 audit(1583019370.774:35): avc: denied { map } for pid=7359 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 [ 39.417145] random: sshd: uninitialized urandom read (32 bytes read) [ 40.125161] random: sshd: uninitialized urandom read (32 bytes read) [ 54.786068] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.1.54' (ECDSA) to the list of known hosts. [ 61.409146] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program [ 61.543156] audit: type=1400 audit(1583019392.954:36): avc: denied { map } for pid=7371 comm="syz-executor108" path="/root/syz-executor108126704" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 61.607590] ================================================================== [ 61.607623] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 61.607630] Write of size 8 at addr ffff88809cf1e248 by task syz-executor108/7380 [ 61.607632] [ 61.607640] CPU: 0 PID: 7380 Comm: syz-executor108 Not tainted 4.14.172-syzkaller #0 [ 61.607645] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.607648] Call Trace: [ 61.607660] dump_stack+0x13e/0x194 [ 61.607669] ? con_shutdown+0x7f/0x90 [ 61.607680] print_address_description.cold+0x7c/0x1e2 [ 61.607689] ? con_shutdown+0x7f/0x90 [ 61.607696] kasan_report.cold+0xa9/0x2ae [ 61.607704] ? set_palette+0x130/0x130 [ 61.607712] con_shutdown+0x7f/0x90 [ 61.607721] release_tty+0xb6/0x7a0 [ 61.607731] tty_release_struct+0x37/0x50 [ 61.607739] tty_release+0xaa6/0xd60 [ 61.607753] ? tty_release_struct+0x50/0x50 [ 61.607761] __fput+0x25f/0x790 [ 61.607777] task_work_run+0x113/0x190 [ 61.607790] do_exit+0x9f2/0x2b00 [ 61.607800] ? __do_page_fault+0x4e4/0xb40 [ 61.607808] ? mm_update_next_owner+0x5b0/0x5b0 [ 61.607816] ? lock_downgrade+0x6e0/0x6e0 [ 61.607827] do_group_exit+0x100/0x310 [ 61.607837] SyS_exit_group+0x19/0x20 [ 61.607843] ? do_group_exit+0x310/0x310 [ 61.607852] do_syscall_64+0x1d5/0x640 [ 61.607866] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 61.607872] RIP: 0033:0x43ff38 [ 61.607877] RSP: 002b:00007ffd36b8bd18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 61.607885] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 61.607889] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 61.607894] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 61.607899] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 61.607903] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 61.607917] [ 61.607921] Allocated by task 7380: [ 61.607928] save_stack+0x32/0xa0 [ 61.607934] kasan_kmalloc+0xbf/0xe0 [ 61.607940] kmem_cache_alloc_trace+0x14d/0x7b0 [ 61.607946] vc_allocate+0x142/0x550 [ 61.607952] con_install+0x4f/0x3e0 [ 61.607958] tty_init_dev+0xe1/0x3a0 [ 61.607965] tty_open+0x410/0x9c0 [ 61.607971] chrdev_open+0x1fc/0x540 [ 61.607979] do_dentry_open+0x732/0xe90 [ 61.607985] vfs_open+0x105/0x220 [ 61.607992] path_openat+0x8ca/0x3c50 [ 61.607998] do_filp_open+0x18e/0x250 [ 61.608005] do_sys_open+0x29d/0x3f0 [ 61.608011] do_syscall_64+0x1d5/0x640 [ 61.608017] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 61.608020] [ 61.608023] Freed by task 7378: [ 61.608029] save_stack+0x32/0xa0 [ 61.608035] kasan_slab_free+0x75/0xc0 [ 61.608040] kfree+0xcb/0x260 [ 61.608049] vt_disallocate_all+0x25c/0x340 [ 61.608054] vt_ioctl+0x6e3/0x1f00 [ 61.608060] tty_ioctl+0x6c5/0x1220 [ 61.608067] do_vfs_ioctl+0x75a/0xfe0 [ 61.608073] SyS_ioctl+0x7f/0xb0 [ 61.608079] do_syscall_64+0x1d5/0x640 [ 61.608086] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 61.608088] [ 61.608093] The buggy address belongs to the object at ffff88809cf1e140 [ 61.608093] which belongs to the cache kmalloc-2048 of size 2048 [ 61.608099] The buggy address is located 264 bytes inside of [ 61.608099] 2048-byte region [ffff88809cf1e140, ffff88809cf1e940) [ 61.608102] The buggy address belongs to the page: [ 61.608108] page:ffffea000273c780 count:1 mapcount:0 mapping:ffff88809cf1e140 index:0x0 compound_mapcount: 0 [ 61.608119] flags: 0xfffe0000008100(slab|head) [ 61.608128] raw: 00fffe0000008100 ffff88809cf1e140 0000000000000000 0000000100000003 [ 61.608136] raw: ffffea0002578220 ffffea00026e4e20 ffff88812fe56c40 0000000000000000 [ 61.608139] page dumped because: kasan: bad access detected [ 61.608141] [ 61.608144] Memory state around the buggy address: [ 61.608150] ffff88809cf1e100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 61.608155] ffff88809cf1e180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 61.608160] >ffff88809cf1e200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 61.608164] ^ [ 61.608169] ffff88809cf1e280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 61.608174] ffff88809cf1e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 61.608177] ================================================================== [ 61.608180] Disabling lock debugging due to kernel taint [ 61.608199] Kernel panic - not syncing: panic_on_warn set ... [ 61.608199] [ 61.608205] CPU: 0 PID: 7380 Comm: syz-executor108 Tainted: G B 4.14.172-syzkaller #0 [ 61.608209] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.608210] Call Trace: [ 61.608220] dump_stack+0x13e/0x194 [ 61.608227] panic+0x1f9/0x42d [ 61.608234] ? add_taint.cold+0x16/0x16 [ 61.608244] ? con_shutdown+0x7f/0x90 [ 61.608251] kasan_end_report+0x43/0x49 [ 61.608258] kasan_report.cold+0x12f/0x2ae [ 61.608264] ? set_palette+0x130/0x130 [ 61.608271] con_shutdown+0x7f/0x90 [ 61.608278] release_tty+0xb6/0x7a0 [ 61.608285] tty_release_struct+0x37/0x50 [ 61.608291] tty_release+0xaa6/0xd60 [ 61.608301] ? tty_release_struct+0x50/0x50 [ 61.608306] __fput+0x25f/0x790 [ 61.608317] task_work_run+0x113/0x190 [ 61.608324] do_exit+0x9f2/0x2b00 [ 61.608331] ? __do_page_fault+0x4e4/0xb40 [ 61.608338] ? mm_update_next_owner+0x5b0/0x5b0 [ 61.608346] ? lock_downgrade+0x6e0/0x6e0 [ 61.608356] do_group_exit+0x100/0x310 [ 61.608363] SyS_exit_group+0x19/0x20 [ 61.608369] ? do_group_exit+0x310/0x310 [ 61.608375] do_syscall_64+0x1d5/0x640 [ 61.608384] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 61.608389] RIP: 0033:0x43ff38 [ 61.608392] RSP: 002b:00007ffd36b8bd18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 61.608399] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 61.608403] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 61.608407] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 61.608411] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 61.608414] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 61.609832] Kernel Offset: disabled [ 62.197419] Rebooting in 86400 seconds..