[....] Starting enhanced syslogd: rsyslogd[ 12.600191] audit: type=1400 audit(1517149610.731:5): avc: denied { syslog } for pid=3526 comm="rsyslogd" capability=34 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1 [?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?25l[?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: [ 18.838739] audit: type=1400 audit(1517149616.969:6): avc: denied { map } for pid=3666 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 '10.128.15.194' (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 [ 25.118766] audit: type=1400 audit(1517149623.249:7): avc: denied { map } for pid=3680 comm="syzkaller844679" path="/root/syzkaller844679463" dev="sda1" ino=16481 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 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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 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 [ 31.033294] ================================================================== [ 31.040703] BUG: KASAN: use-after-free in pppol2tp_connect+0x1a91/0x1dd0 [ 31.047520] Read of size 8 at addr ffff8801d4e07a28 by task syzkaller844679/4707 [ 31.055034] [ 31.056638] CPU: 1 PID: 4707 Comm: syzkaller844679 Not tainted 4.15.0-rc9+ #212 [ 31.064052] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.073377] Call Trace: [ 31.075939] dump_stack+0x194/0x257 [ 31.079545] ? arch_local_irq_restore+0x53/0x53 [ 31.084188] ? show_regs_print_info+0x18/0x18 [ 31.088660] ? lock_release+0xa40/0xa40 [ 31.092609] ? pppol2tp_connect+0x1a91/0x1dd0 [ 31.097081] print_address_description+0x73/0x250 [ 31.101911] ? pppol2tp_connect+0x1a91/0x1dd0 [ 31.106384] kasan_report+0x25b/0x340 [ 31.110160] __asan_report_load8_noabort+0x14/0x20 [ 31.115069] pppol2tp_connect+0x1a91/0x1dd0 [ 31.119373] ? pppol2tp_recv_payload_hook+0x1b0/0x1b0 [ 31.124544] ? selinux_netlbl_socket_connect+0x76/0x1b0 [ 31.129883] ? selinux_socket_connect+0x311/0x730 [ 31.134696] ? lock_downgrade+0x980/0x980 [ 31.138815] ? lock_downgrade+0x980/0x980 [ 31.142937] ? selinux_socket_setsockopt+0x80/0x80 [ 31.147837] ? lock_release+0xa40/0xa40 [ 31.151785] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 31.157644] ? __check_object_size+0x25d/0x4f0 [ 31.162206] ? handle_mm_fault+0x410/0x8d0 [ 31.166420] ? __might_sleep+0x95/0x190 [ 31.170377] ? security_socket_connect+0x89/0xb0 [ 31.175111] SYSC_connect+0x213/0x4a0 [ 31.178888] ? SYSC_bind+0x410/0x410 [ 31.182581] ? do_page_fault+0xee/0x720 [ 31.186528] ? __do_page_fault+0xc90/0xc90 [ 31.190743] ? sock_map_fd+0x53/0x90 [ 31.194428] ? SyS_socket+0x12d/0x1d0 [ 31.198201] ? entry_SYSCALL_64_fastpath+0x5/0xa0 [ 31.203019] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 31.208021] SyS_connect+0x24/0x30 [ 31.211537] entry_SYSCALL_64_fastpath+0x29/0xa0 [ 31.216264] RIP: 0033:0x440c99 [ 31.219424] RSP: 002b:00007ffe6c0c4168 EFLAGS: 00000207 ORIG_RAX: 000000000000002a [ 31.227104] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000440c99 [ 31.234346] RDX: 000000000000002e RSI: 000000002014cfd2 RDI: 0000000000000004 [ 31.241587] RBP: 0000000000007930 R08: 0000000000000000 R09: 0000000000000000 [ 31.248838] R10: 0000000000000000 R11: 0000000000000207 R12: 0000000000000000 [ 31.256079] R13: 0000000000000003 R14: 00000000006cf050 R15: 00000000004a264e [ 31.263336] [ 31.264935] Allocated by task 4706: [ 31.268537] save_stack+0x43/0xd0 [ 31.271959] kasan_kmalloc+0xad/0xe0 [ 31.275642] kasan_slab_alloc+0x12/0x20 [ 31.279586] kmem_cache_alloc+0x12e/0x760 [ 31.283706] sk_prot_alloc+0x65/0x2a0 [ 31.287483] sk_alloc+0x105/0x1440 [ 31.290996] inet6_create+0x44d/0x10f0 [ 31.294854] __sock_create+0x4d4/0x850 [ 31.298710] SyS_socket+0xeb/0x1d0 [ 31.302220] entry_SYSCALL_64_fastpath+0x29/0xa0 [ 31.306941] [ 31.308537] Freed by task 4707: [ 31.311789] save_stack+0x43/0xd0 [ 31.315216] kasan_slab_free+0x71/0xc0 [ 31.319071] kmem_cache_free+0x83/0x2a0 [ 31.323016] __sk_destruct+0x628/0x920 [ 31.326872] sk_destruct+0x47/0x80 [ 31.330380] __sk_free+0xf1/0x2b0 [ 31.333809] sk_free+0x2a/0x40 [ 31.336973] l2tp_session_free+0x21c/0x2b0 [ 31.341176] pppol2tp_session_destruct+0xd4/0x110 [ 31.345987] __sk_destruct+0xfd/0x920 [ 31.349759] sk_destruct+0x47/0x80 [ 31.353267] __sk_free+0xf1/0x2b0 [ 31.356691] sk_free+0x2a/0x40 [ 31.359852] pppol2tp_put_sk+0x49/0x60 [ 31.363712] rcu_process_callbacks+0xd6c/0x17f0 [ 31.368350] __do_softirq+0x2d7/0xb85 [ 31.372117] [ 31.373718] The buggy address belongs to the object at ffff8801d4e07800 [ 31.373718] which belongs to the cache UDPv6 of size 1664 [ 31.385909] The buggy address is located 552 bytes inside of [ 31.385909] 1664-byte region [ffff8801d4e07800, ffff8801d4e07e80) [ 31.397839] The buggy address belongs to the page: [ 31.402741] page:ffffea00075381c0 count:1 mapcount:0 mapping:ffff8801d4e07100 index:0x0 [ 31.410865] flags: 0x2fffc0000000100(slab) [ 31.415071] raw: 02fffc0000000100 ffff8801d4e07100 0000000000000000 0000000100000002 [ 31.422922] raw: ffffea00074b96e0 ffff8801d33d5848 ffff8801d3395d80 0000000000000000 [ 31.430781] page dumped because: kasan: bad access detected [ 31.436464] [ 31.438060] Memory state around the buggy address: [ 31.442958] ffff8801d4e07900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.450288] ffff8801d4e07980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.457616] >ffff8801d4e07a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.464944] ^ [ 31.469581] ffff8801d4e07a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.476909] ffff8801d4e07b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.484236] ================================================================== [ 31.491561] Disabling lock debugging due to kernel taint [ 31.497061] Kernel panic - not syncing: panic_on_warn set ... [ 31.497061] [ 31.504403] CPU: 1 PID: 4707 Comm: syzkaller844679 Tainted: G B 4.15.0-rc9+ #212 [ 31.513122] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.522464] Call Trace: [ 31.525030] dump_stack+0x194/0x257 [ 31.528628] ? arch_local_irq_restore+0x53/0x53 [ 31.533270] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 31.537995] ? vsnprintf+0x1ed/0x1900 [ 31.541767] ? pppol2tp_connect+0x1a40/0x1dd0 [ 31.546235] panic+0x1e4/0x41c [ 31.549396] ? refcount_error_report+0x214/0x214 [ 31.554123] ? add_taint+0x1c/0x50 [ 31.557635] ? add_taint+0x1c/0x50 [ 31.561144] ? pppol2tp_connect+0x1a91/0x1dd0 [ 31.565620] kasan_end_report+0x50/0x50 [ 31.569564] kasan_report+0x144/0x340 [ 31.573336] __asan_report_load8_noabort+0x14/0x20 [ 31.578233] pppol2tp_connect+0x1a91/0x1dd0 [ 31.582540] ? pppol2tp_recv_payload_hook+0x1b0/0x1b0 [ 31.587703] ? selinux_netlbl_socket_connect+0x76/0x1b0 [ 31.593042] ? selinux_socket_connect+0x311/0x730 [ 31.597856] ? lock_downgrade+0x980/0x980 [ 31.601973] ? lock_downgrade+0x980/0x980 [ 31.606092] ? selinux_socket_setsockopt+0x80/0x80 [ 31.610989] ? lock_release+0xa40/0xa40 [ 31.614934] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 31.620790] ? __check_object_size+0x25d/0x4f0 [ 31.625343] ? handle_mm_fault+0x410/0x8d0 [ 31.629558] ? __might_sleep+0x95/0x190 [ 31.633518] ? security_socket_connect+0x89/0xb0 [ 31.638248] SYSC_connect+0x213/0x4a0 [ 31.642024] ? SYSC_bind+0x410/0x410 [ 31.645722] ? do_page_fault+0xee/0x720 [ 31.649668] ? __do_page_fault+0xc90/0xc90 [ 31.653877] ? sock_map_fd+0x53/0x90 [ 31.657560] ? SyS_socket+0x12d/0x1d0 [ 31.661329] ? entry_SYSCALL_64_fastpath+0x5/0xa0 [ 31.666143] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 31.671130] SyS_connect+0x24/0x30 [ 31.674642] entry_SYSCALL_64_fastpath+0x29/0xa0 [ 31.679366] RIP: 0033:0x440c99 [ 31.682525] RSP: 002b:00007ffe6c0c4168 EFLAGS: 00000207 ORIG_RAX: 000000000000002a [ 31.690205] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000440c99 [ 31.697446] RDX: 000000000000002e RSI: 000000002014cfd2 RDI: 0000000000000004 [ 31.704694] RBP: 0000000000007930 R08: 0000000000000000 R09: 0000000000000000 [ 31.711938] R10: 0000000000000000 R11: 0000000000000207 R12: 0000000000000000 [ 31.719178] R13: 0000000000000003 R14: 00000000006cf050 R15: 00000000004a264e [ 31.726886] Dumping ftrace buffer: [ 31.730411] (ftrace buffer empty) [ 31.734094] Kernel Offset: disabled [ 31.737692] Rebooting in 86400 seconds..