[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [ 39.855502] audit: type=1800 audit(1575809293.172:33): pid=7457 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 [ 39.878787] audit: type=1800 audit(1575809293.182:34): pid=7457 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 [ 40.660566] audit: type=1400 audit(1575809293.982:35): avc: denied { map } for pid=7630 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 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.130' (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 executing program executing program executing program executing program executing program syzkaller login: [ 47.376911] audit: type=1400 audit(1575809300.702:36): avc: denied { map } for pid=7643 comm="syz-executor249" path="/root/syz-executor249122949" 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 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 [ 47.602482] ================================================================== [ 47.610170] BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x24b0/0x28e0 [ 47.610186] Read of size 1 at addr ffff888096ff0001 by task syz-executor249/7692 [ 47.625220] [ 47.626849] CPU: 0 PID: 7692 Comm: syz-executor249 Not tainted 4.19.88-syzkaller #0 [ 47.626855] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.626860] Call Trace: [ 47.626880] dump_stack+0x197/0x210 [ 47.626899] ? n_tty_receive_buf_common+0x24b0/0x28e0 [ 47.626916] print_address_description.cold+0x7c/0x20d [ 47.626931] ? n_tty_receive_buf_common+0x24b0/0x28e0 [ 47.626944] kasan_report.cold+0x8c/0x2ba [ 47.626961] __asan_report_load1_noabort+0x14/0x20 [ 47.626975] n_tty_receive_buf_common+0x24b0/0x28e0 [ 47.680068] n_tty_receive_buf2+0x34/0x40 [ 47.680086] tty_ldisc_receive_buf+0xad/0x1c0 [ 47.680100] ? add_wait_queue+0x112/0x170 [ 47.680112] ? n_tty_receive_buf_common+0x28e0/0x28e0 [ 47.680129] paste_selection+0x1ff/0x443 [ 47.680148] ? set_selection+0x1370/0x1370 [ 47.680166] ? lock_downgrade+0x880/0x880 [ 47.680178] ? wake_up_q+0x100/0x100 [ 47.680202] tioclinux+0x133/0x470 [ 47.680217] vt_ioctl+0x19ab/0x2530 [ 47.680233] ? complete_change_console+0x3a0/0x3a0 [ 47.680247] ? avc_has_extended_perms+0xa78/0x10f0 [ 47.680264] ? lock_downgrade+0x880/0x880 [ 47.680285] ? avc_ss_reset+0x190/0x190 [ 47.680298] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 47.744719] ? tty_jobctrl_ioctl+0x50/0xcd0 [ 47.744733] ? complete_change_console+0x3a0/0x3a0 [ 47.744746] tty_ioctl+0x7f3/0x1510 [ 47.744762] ? tty_vhangup+0x30/0x30 [ 47.744775] ? thp_get_unmapped_area+0x1f0/0x1f0 [ 47.744798] ? __handle_mm_fault+0x7d1/0x3f80 [ 47.744820] ? __might_sleep+0x95/0x190 [ 47.744832] ? tty_vhangup+0x30/0x30 [ 47.744848] do_vfs_ioctl+0xd5f/0x1380 [ 47.782340] ? selinux_file_ioctl+0x46f/0x5e0 [ 47.782352] ? selinux_file_ioctl+0x125/0x5e0 [ 47.782368] ? ioctl_preallocate+0x210/0x210 [ 47.782381] ? selinux_file_mprotect+0x620/0x620 [ 47.782398] ? gup_pgd_range+0x21ec/0x3910 [ 47.782415] ? __sanitizer_cov_trace_cmp1+0xb/0x20 [ 47.782434] ? up_read+0x1a/0x110 [ 47.782447] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 47.782465] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 47.782479] ? security_file_ioctl+0x8d/0xc0 [ 47.782495] ksys_ioctl+0xab/0xd0 [ 47.782511] __x64_sys_ioctl+0x73/0xb0 [ 47.782527] do_syscall_64+0xfd/0x620 [ 47.782544] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.782554] RIP: 0033:0x441309 [ 47.782567] 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 [ 47.782575] RSP: 002b:00007ffee457a6b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 47.782586] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441309 [ 47.782593] RDX: 0000000020000000 RSI: 000000000000541c RDI: 0000000000000003 [ 47.782601] RBP: 000000000000b98a R08: 000000000000000d R09: 00000000004002c8 [ 47.782608] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402080 [ 47.782616] R13: 0000000000402110 R14: 0000000000000000 R15: 0000000000000000 [ 47.782634] [ 47.782641] Allocated by task 7693: [ 47.782655] save_stack+0x45/0xd0 [ 47.782666] kasan_kmalloc+0xce/0xf0 [ 47.782676] __kmalloc+0x15d/0x750 [ 47.782688] set_selection+0x7e4/0x1370 [ 47.782702] tioclinux+0x11c/0x470 [ 47.934430] vt_ioctl+0x19ab/0x2530 [ 47.934440] tty_ioctl+0x7f3/0x1510 [ 47.934451] do_vfs_ioctl+0xd5f/0x1380 [ 47.934460] ksys_ioctl+0xab/0xd0 [ 47.934470] __x64_sys_ioctl+0x73/0xb0 [ 47.934484] do_syscall_64+0xfd/0x620 [ 47.934497] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.934501] [ 47.934506] Freed by task 7694: [ 47.934518] save_stack+0x45/0xd0 [ 47.934529] __kasan_slab_free+0x102/0x150 [ 47.934545] kasan_slab_free+0xe/0x10 [ 47.934559] kfree+0xcf/0x220 [ 47.981461] set_selection+0x801/0x1370 [ 47.981473] tioclinux+0x11c/0x470 [ 47.981482] vt_ioctl+0x19ab/0x2530 [ 47.981492] tty_ioctl+0x7f3/0x1510 [ 47.981503] do_vfs_ioctl+0xd5f/0x1380 [ 47.981513] ksys_ioctl+0xab/0xd0 [ 47.981523] __x64_sys_ioctl+0x73/0xb0 [ 47.981541] do_syscall_64+0xfd/0x620 [ 47.981554] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.981558] [ 47.981568] The buggy address belongs to the object at ffff888096ff0000 [ 47.981568] which belongs to the cache kmalloc-32 of size 32 [ 47.981578] The buggy address is located 1 bytes inside of [ 47.981578] 32-byte region [ffff888096ff0000, ffff888096ff0020) [ 47.981586] The buggy address belongs to the page: [ 48.046979] page:ffffea00025bfc00 count:1 mapcount:0 mapping:ffff88812c31c1c0 index:0xffff888096ff0fc1 [ 48.046990] flags: 0xfffe0000000100(slab) [ 48.047004] raw: 00fffe0000000100 ffffea0002931cc8 ffffea0002935008 ffff88812c31c1c0 [ 48.047018] raw: ffff888096ff0fc1 ffff888096ff0000 0000000100000037 0000000000000000 [ 48.047023] page dumped because: kasan: bad access detected [ 48.047026] [ 48.047030] Memory state around the buggy address: [ 48.047045] ffff888096feff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 48.047055] ffff888096feff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 48.047064] >ffff888096ff0000: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc [ 48.047069] ^ [ 48.047078] ffff888096ff0080: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc [ 48.047087] ffff888096ff0100: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc [ 48.047091] ================================================================== [ 48.047095] Disabling lock debugging due to kernel taint [ 48.048558] Kernel panic - not syncing: panic_on_warn set ... [ 48.048558] [ 48.148933] CPU: 0 PID: 7692 Comm: syz-executor249 Tainted: G B 4.19.88-syzkaller #0 [ 48.148940] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.148943] Call Trace: [ 48.148966] dump_stack+0x197/0x210 [ 48.148982] ? n_tty_receive_buf_common+0x24b0/0x28e0 [ 48.148993] panic+0x26a/0x50e [ 48.149004] ? __warn_printk+0xf3/0xf3 [ 48.149017] ? n_tty_receive_buf_common+0x24b0/0x28e0 [ 48.149030] ? preempt_schedule+0x4b/0x60 [ 48.149043] ? ___preempt_schedule+0x16/0x18 [ 48.149055] ? trace_hardirqs_on+0x5e/0x220 [ 48.149071] ? n_tty_receive_buf_common+0x24b0/0x28e0 [ 48.209213] kasan_end_report+0x47/0x4f [ 48.209227] kasan_report.cold+0xa9/0x2ba [ 48.209241] __asan_report_load1_noabort+0x14/0x20 [ 48.209255] n_tty_receive_buf_common+0x24b0/0x28e0 [ 48.209277] n_tty_receive_buf2+0x34/0x40 [ 48.209290] tty_ldisc_receive_buf+0xad/0x1c0 [ 48.209304] ? add_wait_queue+0x112/0x170 [ 48.209315] ? n_tty_receive_buf_common+0x28e0/0x28e0 [ 48.209328] paste_selection+0x1ff/0x443 [ 48.209344] ? set_selection+0x1370/0x1370 [ 48.253786] ? lock_downgrade+0x880/0x880 [ 48.253797] ? wake_up_q+0x100/0x100 [ 48.253815] tioclinux+0x133/0x470 [ 48.253830] vt_ioctl+0x19ab/0x2530 [ 48.253844] ? complete_change_console+0x3a0/0x3a0 [ 48.253859] ? avc_has_extended_perms+0xa78/0x10f0 [ 48.253873] ? lock_downgrade+0x880/0x880 [ 48.253887] ? avc_ss_reset+0x190/0x190 [ 48.253899] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 48.253913] ? tty_jobctrl_ioctl+0x50/0xcd0 [ 48.253925] ? complete_change_console+0x3a0/0x3a0 [ 48.253936] tty_ioctl+0x7f3/0x1510 [ 48.253949] ? tty_vhangup+0x30/0x30 [ 48.253961] ? thp_get_unmapped_area+0x1f0/0x1f0 [ 48.253978] ? __handle_mm_fault+0x7d1/0x3f80 [ 48.253995] ? __might_sleep+0x95/0x190 [ 48.254005] ? tty_vhangup+0x30/0x30 [ 48.254018] do_vfs_ioctl+0xd5f/0x1380 [ 48.254030] ? selinux_file_ioctl+0x46f/0x5e0 [ 48.254041] ? selinux_file_ioctl+0x125/0x5e0 [ 48.254053] ? ioctl_preallocate+0x210/0x210 [ 48.254064] ? selinux_file_mprotect+0x620/0x620 [ 48.254080] ? gup_pgd_range+0x21ec/0x3910 [ 48.351980] ? __sanitizer_cov_trace_cmp1+0xb/0x20 [ 48.351993] ? up_read+0x1a/0x110 [ 48.352003] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 48.352016] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 48.352029] ? security_file_ioctl+0x8d/0xc0 [ 48.352043] ksys_ioctl+0xab/0xd0 [ 48.352059] __x64_sys_ioctl+0x73/0xb0 [ 48.352075] do_syscall_64+0xfd/0x620 [ 48.352091] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.352100] RIP: 0033:0x441309 [ 48.352112] 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 [ 48.352118] RSP: 002b:00007ffee457a6b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 48.352130] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441309 [ 48.352137] RDX: 0000000020000000 RSI: 000000000000541c RDI: 0000000000000003 [ 48.352143] RBP: 000000000000b98a R08: 000000000000000d R09: 00000000004002c8 [ 48.352155] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402080 [ 48.451138] R13: 0000000000402110 R14: 0000000000000000 R15: 0000000000000000 [ 48.452707] Kernel Offset: disabled [ 48.463668] Rebooting in 86400 seconds..