[ 37.273619] audit: type=1800 audit(1583861874.239:33): pid=7379 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="startpar" name="rc.local" dev="sda1" ino=2465 res=0 [ 37.299952] audit: type=1800 audit(1583861874.239:34): pid=7379 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="startpar" name="rmnologin" dev="sda1" ino=2456 res=0 Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 41.982993] random: sshd: uninitialized urandom read (32 bytes read) [ 42.367323] audit: type=1400 audit(1583861879.329:35): avc: denied { map } for pid=7550 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 [ 42.420432] random: sshd: uninitialized urandom read (32 bytes read) [ 43.223044] random: sshd: uninitialized urandom read (32 bytes read) [ 43.419105] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.92' (ECDSA) to the list of known hosts. [ 49.004902] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program [ 49.128257] audit: type=1400 audit(1583861886.089:36): avc: denied { map } for pid=7562 comm="syz-executor291" path="/root/syz-executor291796631" 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 [ 49.184972] ================================================================== [ 49.185007] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 49.185014] Write of size 8 at addr ffff88808928cd88 by task syz-executor291/7570 [ 49.185017] [ 49.185025] CPU: 1 PID: 7570 Comm: syz-executor291 Not tainted 4.14.172-syzkaller #0 [ 49.185030] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 49.185033] Call Trace: [ 49.185046] dump_stack+0x13e/0x194 [ 49.185056] ? con_shutdown+0x7f/0x90 [ 49.185067] print_address_description.cold+0x7c/0x1e2 [ 49.185076] ? con_shutdown+0x7f/0x90 [ 49.185083] kasan_report.cold+0xa9/0x2ae [ 49.185091] ? set_palette+0x130/0x130 [ 49.185099] con_shutdown+0x7f/0x90 [ 49.185108] release_tty+0xb6/0x7a0 [ 49.185117] tty_release_struct+0x37/0x50 [ 49.185126] tty_release+0xaa6/0xd60 [ 49.185139] ? tty_release_struct+0x50/0x50 [ 49.185147] __fput+0x25f/0x790 [ 49.185163] task_work_run+0x113/0x190 [ 49.185174] do_exit+0x9f2/0x2b00 [ 49.185183] ? __do_page_fault+0x4e4/0xb40 [ 49.185193] ? mm_update_next_owner+0x5b0/0x5b0 [ 49.185205] ? lock_downgrade+0x6e0/0x6e0 [ 49.185219] do_group_exit+0x100/0x310 [ 49.185229] SyS_exit_group+0x19/0x20 [ 49.185235] ? do_group_exit+0x310/0x310 [ 49.185244] do_syscall_64+0x1d5/0x640 [ 49.185258] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.185265] RIP: 0033:0x43ff38 [ 49.185270] RSP: 002b:00007ffd8eac7b28 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 49.185278] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 49.185283] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 49.185288] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 49.185292] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 49.185297] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 49.185310] [ 49.185314] Allocated by task 7570: [ 49.185322] save_stack+0x32/0xa0 [ 49.185328] kasan_kmalloc+0xbf/0xe0 [ 49.185334] kmem_cache_alloc_trace+0x14d/0x7b0 [ 49.185340] vc_allocate+0x142/0x550 [ 49.185346] con_install+0x4f/0x3e0 [ 49.185353] tty_init_dev+0xe1/0x3a0 [ 49.185359] tty_open+0x410/0x9c0 [ 49.185366] chrdev_open+0x1fc/0x540 [ 49.185374] do_dentry_open+0x732/0xe90 [ 49.185381] vfs_open+0x105/0x220 [ 49.185387] path_openat+0x8ca/0x3c50 [ 49.185393] do_filp_open+0x18e/0x250 [ 49.185400] do_sys_open+0x29d/0x3f0 [ 49.185406] do_syscall_64+0x1d5/0x640 [ 49.185412] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.185415] [ 49.185418] Freed by task 7572: [ 49.185424] save_stack+0x32/0xa0 [ 49.185430] kasan_slab_free+0x75/0xc0 [ 49.185436] kfree+0xcb/0x260 [ 49.185444] vt_disallocate_all+0x25c/0x340 [ 49.185449] vt_ioctl+0x6e3/0x1f00 [ 49.185455] tty_ioctl+0x6c5/0x1220 [ 49.185461] do_vfs_ioctl+0x75a/0xfe0 [ 49.185467] SyS_ioctl+0x7f/0xb0 [ 49.185473] do_syscall_64+0x1d5/0x640 [ 49.185479] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.185482] [ 49.185487] The buggy address belongs to the object at ffff88808928cc80 [ 49.185487] which belongs to the cache kmalloc-2048 of size 2048 [ 49.185493] The buggy address is located 264 bytes inside of [ 49.185493] 2048-byte region [ffff88808928cc80, ffff88808928d480) [ 49.185496] The buggy address belongs to the page: [ 49.185503] page:ffffea000224a300 count:1 mapcount:0 mapping:ffff88808928c400 index:0x0 compound_mapcount: 0 [ 49.185513] flags: 0xfffe0000008100(slab|head) [ 49.185524] raw: 00fffe0000008100 ffff88808928c400 0000000000000000 0000000100000003 [ 49.185532] raw: ffffea000224f8a0 ffffea000234ea20 ffff88812fe56c40 0000000000000000 [ 49.185536] page dumped because: kasan: bad access detected [ 49.185538] [ 49.185541] Memory state around the buggy address: [ 49.185548] ffff88808928cc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.185554] ffff88808928cd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.185560] >ffff88808928cd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.185563] ^ [ 49.185569] ffff88808928ce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.185575] ffff88808928ce80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.185578] ================================================================== [ 49.185581] Disabling lock debugging due to kernel taint [ 49.185585] Kernel panic - not syncing: panic_on_warn set ... [ 49.185585] [ 49.185593] CPU: 1 PID: 7570 Comm: syz-executor291 Tainted: G B 4.14.172-syzkaller #0 [ 49.185596] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 49.185598] Call Trace: [ 49.185607] dump_stack+0x13e/0x194 [ 49.185614] panic+0x1f9/0x42d [ 49.185621] ? add_taint.cold+0x16/0x16 [ 49.185629] ? lock_downgrade+0x6e0/0x6e0 [ 49.185637] ? con_shutdown+0x7f/0x90 [ 49.185644] kasan_end_report+0x43/0x49 [ 49.185650] kasan_report.cold+0x12f/0x2ae [ 49.185657] ? set_palette+0x130/0x130 [ 49.185674] con_shutdown+0x7f/0x90 [ 49.185681] release_tty+0xb6/0x7a0 [ 49.185689] tty_release_struct+0x37/0x50 [ 49.185696] tty_release+0xaa6/0xd60 [ 49.185706] ? tty_release_struct+0x50/0x50 [ 49.185711] __fput+0x25f/0x790 [ 49.185721] task_work_run+0x113/0x190 [ 49.185730] do_exit+0x9f2/0x2b00 [ 49.185737] ? __do_page_fault+0x4e4/0xb40 [ 49.185746] ? mm_update_next_owner+0x5b0/0x5b0 [ 49.185753] ? lock_downgrade+0x6e0/0x6e0 [ 49.185763] do_group_exit+0x100/0x310 [ 49.185771] SyS_exit_group+0x19/0x20 [ 49.185777] ? do_group_exit+0x310/0x310 [ 49.185783] do_syscall_64+0x1d5/0x640 [ 49.185793] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.185798] RIP: 0033:0x43ff38 [ 49.185801] RSP: 002b:00007ffd8eac7b28 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 49.185808] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 49.185812] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 49.185816] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 49.185819] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 49.185823] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 49.187321] Kernel Offset: disabled