[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [ 91.462665][ T27] audit: type=1400 audit(1581912237.376:37): avc: denied { watch } for pid=10743 comm="restorecond" path="/root/.ssh" dev="sda1" ino=16179 scontext=system_u:system_r:kernel_t:s0 tcontext=unconfined_u:object_r:ssh_home_t:s0 tclass=dir permissive=1 [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 96.704592][ T27] kauditd_printk_skb: 3 callbacks suppressed [ 96.704607][ T27] audit: type=1400 audit(1581912242.616:41): avc: denied { map } for pid=10832 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 Warning: Permanently added '10.128.10.56' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 484.535719][ T27] audit: type=1400 audit(1581912630.446:42): avc: denied { map } for pid=10844 comm="syz-executor319" path="/root/syz-executor319935387" dev="sda1" ino=1426 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 485.862310][T11030] ================================================================== [ 485.862457][T11030] BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x270f/0x2b70 [ 485.862476][T11030] Read of size 1 at addr ffff8880a7648402 by task syz-executor319/11030 [ 485.887756][T11030] [ 485.887776][T11030] CPU: 0 PID: 11030 Comm: syz-executor319 Not tainted 5.6.0-rc2-syzkaller #0 [ 485.887782][T11030] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 485.887787][T11030] Call Trace: [ 485.887941][T11030] dump_stack+0x197/0x210 [ 485.887962][T11030] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 485.888025][T11030] print_address_description.constprop.0.cold+0xd4/0x30b [ 485.888046][T11030] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 485.935833][T11030] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 485.935850][T11030] __kasan_report.cold+0x1b/0x32 [ 485.935871][T11030] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 485.935892][T11030] kasan_report+0x12/0x20 [ 485.936014][T11030] __asan_report_load1_noabort+0x14/0x20 [ 485.936030][T11030] n_tty_receive_buf_common+0x270f/0x2b70 [ 485.936046][T11030] ? __kasan_check_read+0x11/0x20 [ 485.936097][T11030] n_tty_receive_buf2+0x34/0x40 [ 485.978684][T11030] tty_ldisc_receive_buf+0xad/0x1c0 [ 485.978779][T11030] ? add_wait_queue+0x112/0x170 [ 485.978794][T11030] ? n_tty_receive_buf_common+0x2b70/0x2b70 [ 485.978825][T11030] paste_selection+0x1ff/0x460 [ 485.978853][T11030] ? vcs_remove_sysfs+0x60/0x60 [ 486.004732][T11030] ? lock_downgrade+0x920/0x920 [ 486.004822][T11030] ? wake_up_q+0x140/0x140 [ 486.004859][T11030] tioclinux+0x133/0x480 [ 486.004880][T11030] vt_ioctl+0x1a41/0x26d0 [ 486.004901][T11030] ? complete_change_console+0x3a0/0x3a0 [ 486.004952][T11030] ? tomoyo_execute_permission+0x4a0/0x4a0 [ 486.005010][T11030] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 486.040482][T11030] ? tty_jobctrl_ioctl+0x50/0xd40 [ 486.040497][T11030] ? complete_change_console+0x3a0/0x3a0 [ 486.040515][T11030] tty_ioctl+0xa37/0x14f0 [ 486.040535][T11030] ? tty_vhangup+0x30/0x30 [ 486.040552][T11030] ? __sanitizer_cov_trace_const_cmp2+0x18/0x20 [ 486.040634][T11030] ? do_vfs_ioctl+0x568/0x13b0 [ 486.040659][T11030] ? ioctl_file_clone+0x180/0x180 [ 486.040713][T11030] ? selinux_file_mprotect+0x620/0x620 [ 486.040791][T11030] ? file_open_root+0x430/0x430 [ 486.086621][T11030] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 486.086658][T11030] ? tomoyo_file_ioctl+0x23/0x30 [ 486.086682][T11030] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 486.104184][T11030] ? security_file_ioctl+0x8d/0xc0 [ 486.104200][T11030] ? tty_vhangup+0x30/0x30 [ 486.104222][T11030] ksys_ioctl+0x123/0x180 [ 486.118223][T11030] __x64_sys_ioctl+0x73/0xb0 [ 486.118317][T11030] do_syscall_64+0xfa/0x790 [ 486.118375][T11030] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 486.118386][T11030] RIP: 0033:0x441329 [ 486.118401][T11030] Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 486.118408][T11030] RSP: 002b:00007ffeae838978 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 486.118423][T11030] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441329 [ 486.118431][T11030] RDX: 0000000020000040 RSI: 000000000000541c RDI: 0000000000000004 [ 486.118440][T11030] RBP: 0000000000076975 R08: 000000000000000d R09: 00000000004002c8 [ 486.118447][T11030] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004020a0 [ 486.118455][T11030] R13: 0000000000402130 R14: 0000000000000000 R15: 0000000000000000 [ 486.118485][T11030] [ 486.118493][T11030] Allocated by task 11034: [ 486.118508][T11030] save_stack+0x23/0x90 [ 486.118521][T11030] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 486.118532][T11030] kasan_kmalloc+0x9/0x10 [ 486.118542][T11030] __kmalloc+0x163/0x770 [ 486.118556][T11030] set_selection_kernel+0x872/0x13b0 [ 486.118569][T11030] set_selection_user+0x95/0xd9 [ 486.118580][T11030] tioclinux+0x11c/0x480 [ 486.118592][T11030] vt_ioctl+0x1a41/0x26d0 [ 486.118603][T11030] tty_ioctl+0xa37/0x14f0 [ 486.118616][T11030] ksys_ioctl+0x123/0x180 [ 486.118634][T11030] __x64_sys_ioctl+0x73/0xb0 [ 486.263531][T11030] do_syscall_64+0xfa/0x790 [ 486.263549][T11030] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 486.263554][T11030] [ 486.263561][T11030] Freed by task 11036: [ 486.263574][T11030] save_stack+0x23/0x90 [ 486.263587][T11030] __kasan_slab_free+0x102/0x150 [ 486.263600][T11030] kasan_slab_free+0xe/0x10 [ 486.263611][T11030] kfree+0x10a/0x2c0 [ 486.263627][T11030] set_selection_kernel+0x88f/0x13b0 [ 486.263640][T11030] set_selection_user+0x95/0xd9 [ 486.263656][T11030] tioclinux+0x11c/0x480 [ 486.263666][T11030] vt_ioctl+0x1a41/0x26d0 [ 486.263678][T11030] tty_ioctl+0xa37/0x14f0 [ 486.263691][T11030] ksys_ioctl+0x123/0x180 [ 486.263701][T11030] __x64_sys_ioctl+0x73/0xb0 [ 486.263714][T11030] do_syscall_64+0xfa/0x790 [ 486.263727][T11030] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 486.263731][T11030] [ 486.263741][T11030] The buggy address belongs to the object at ffff8880a7648400 [ 486.263741][T11030] which belongs to the cache kmalloc-512 of size 512 [ 486.263753][T11030] The buggy address is located 2 bytes inside of [ 486.263753][T11030] 512-byte region [ffff8880a7648400, ffff8880a7648600) [ 486.263758][T11030] The buggy address belongs to the page: [ 486.263772][T11030] page:ffffea00029d9200 refcount:1 mapcount:0 mapping:ffff8880aa400a80 index:0x0 [ 486.263782][T11030] flags: 0xfffe0000000200(slab) [ 486.263802][T11030] raw: 00fffe0000000200 ffffea00029c3a48 ffffea00027a7488 ffff8880aa400a80 [ 486.398627][T11030] raw: 0000000000000000 ffff8880a7648000 0000000100000004 0000000000000000 [ 486.398633][T11030] page dumped because: kasan: bad access detected [ 486.398637][T11030] [ 486.398640][T11030] Memory state around the buggy address: [ 486.398652][T11030] ffff8880a7648300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 486.398661][T11030] ffff8880a7648380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 486.398670][T11030] >ffff8880a7648400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 486.398676][T11030] ^ [ 486.398685][T11030] ffff8880a7648480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 486.398696][T11030] ffff8880a7648500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 486.398701][T11030] ================================================================== [ 486.398705][T11030] Disabling lock debugging due to kernel taint [ 486.402376][T11030] Kernel panic - not syncing: panic_on_warn set ... [ 486.487369][T11030] CPU: 0 PID: 11030 Comm: syz-executor319 Tainted: G B 5.6.0-rc2-syzkaller #0 [ 486.487376][T11030] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 486.487380][T11030] Call Trace: [ 486.487402][T11030] dump_stack+0x197/0x210 [ 486.487487][T11030] panic+0x2e3/0x75c [ 486.487500][T11030] ? add_taint.cold+0x16/0x16 [ 486.487517][T11030] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 486.487546][T11030] ? preempt_schedule+0x4b/0x60 [ 486.487561][T11030] ? ___preempt_schedule+0x16/0x18 [ 486.487613][T11030] ? trace_hardirqs_on+0x5e/0x240 [ 486.487634][T11030] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 486.550773][T11030] end_report+0x47/0x4f [ 486.550788][T11030] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 486.550801][T11030] __kasan_report.cold+0xe/0x32 [ 486.550817][T11030] ? n_tty_receive_buf_common+0x270f/0x2b70 [ 486.550833][T11030] kasan_report+0x12/0x20 [ 486.550849][T11030] __asan_report_load1_noabort+0x14/0x20 [ 486.550862][T11030] n_tty_receive_buf_common+0x270f/0x2b70 [ 486.550875][T11030] ? __kasan_check_read+0x11/0x20 [ 486.550909][T11030] n_tty_receive_buf2+0x34/0x40 [ 486.597682][T11030] tty_ldisc_receive_buf+0xad/0x1c0 [ 486.597693][T11030] ? add_wait_queue+0x112/0x170 [ 486.597703][T11030] ? n_tty_receive_buf_common+0x2b70/0x2b70 [ 486.597716][T11030] paste_selection+0x1ff/0x460 [ 486.597729][T11030] ? vcs_remove_sysfs+0x60/0x60 [ 486.597741][T11030] ? lock_downgrade+0x920/0x920 [ 486.597755][T11030] ? wake_up_q+0x140/0x140 [ 486.597774][T11030] tioclinux+0x133/0x480 [ 486.597787][T11030] vt_ioctl+0x1a41/0x26d0 [ 486.597803][T11030] ? complete_change_console+0x3a0/0x3a0 [ 486.597820][T11030] ? tomoyo_execute_permission+0x4a0/0x4a0 [ 486.597841][T11030] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 486.597855][T11030] ? tty_jobctrl_ioctl+0x50/0xd40 [ 486.597868][T11030] ? complete_change_console+0x3a0/0x3a0 [ 486.597881][T11030] tty_ioctl+0xa37/0x14f0 [ 486.597900][T11030] ? tty_vhangup+0x30/0x30 [ 486.679045][T11030] ? __sanitizer_cov_trace_const_cmp2+0x18/0x20 [ 486.679063][T11030] ? do_vfs_ioctl+0x568/0x13b0 [ 486.679080][T11030] ? ioctl_file_clone+0x180/0x180 [ 486.679093][T11030] ? selinux_file_mprotect+0x620/0x620 [ 486.679106][T11030] ? file_open_root+0x430/0x430 [ 486.679125][T11030] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 486.679148][T11030] ? tomoyo_file_ioctl+0x23/0x30 [ 486.679162][T11030] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 486.679185][T11030] ? security_file_ioctl+0x8d/0xc0 [ 486.679199][T11030] ? tty_vhangup+0x30/0x30 [ 486.679214][T11030] ksys_ioctl+0x123/0x180 [ 486.679231][T11030] __x64_sys_ioctl+0x73/0xb0 [ 486.679248][T11030] do_syscall_64+0xfa/0x790 [ 486.679266][T11030] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 486.679277][T11030] RIP: 0033:0x441329 [ 486.679291][T11030] Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 486.679298][T11030] RSP: 002b:00007ffeae838978 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 486.679310][T11030] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441329 [ 486.679318][T11030] RDX: 0000000020000040 RSI: 000000000000541c RDI: 0000000000000004 [ 486.679325][T11030] RBP: 0000000000076975 R08: 000000000000000d R09: 00000000004002c8 [ 486.679333][T11030] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004020a0 [ 486.679341][T11030] R13: 0000000000402130 R14: 0000000000000000 R15: 0000000000000000 [ 486.687482][T11030] Kernel Offset: disabled [ 486.831445][T11030] Rebooting in 86400 seconds..