[....] Starting enhanced syslogd: rsyslogd[ 13.311387] audit: type=1400 audit(1516626955.395:5): avc: denied { syslog } for pid=3504 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: [ 19.617620] audit: type=1400 audit(1516626961.701:6): avc: denied { map } for pid=3645 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 '10.128.0.57' (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 [ 25.962542] audit: type=1400 audit(1516626968.046:7): avc: denied { map } for pid=3659 comm="syzkaller636167" path="/root/syzkaller636167192" 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 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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 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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 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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 [ 27.822273] ================================================================== [ 27.829686] BUG: KASAN: use-after-free in pppol2tp_connect+0x1a91/0x1dd0 [ 27.836508] Read of size 8 at addr ffff8801d7d30ae8 by task syzkaller636167/4198 [ 27.844013] [ 27.845623] CPU: 1 PID: 4198 Comm: syzkaller636167 Not tainted 4.15.0-rc8+ #202 [ 27.853042] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 27.862374] Call Trace: [ 27.864941] dump_stack+0x194/0x257 [ 27.868548] ? arch_local_irq_restore+0x53/0x53 [ 27.873933] ? show_regs_print_info+0x18/0x18 [ 27.878425] ? lock_release+0xa40/0xa40 [ 27.882380] ? pppol2tp_connect+0x1a91/0x1dd0 [ 27.886853] print_address_description+0x73/0x250 [ 27.891679] ? pppol2tp_connect+0x1a91/0x1dd0 [ 27.896160] kasan_report+0x25b/0x340 [ 27.899941] __asan_report_load8_noabort+0x14/0x20 [ 27.904850] pppol2tp_connect+0x1a91/0x1dd0 [ 27.909158] ? pppol2tp_recv_payload_hook+0x1b0/0x1b0 [ 27.914337] ? selinux_netlbl_socket_connect+0x76/0x1b0 [ 27.919681] ? selinux_socket_connect+0x311/0x730 [ 27.924504] ? lock_downgrade+0x980/0x980 [ 27.928625] ? lock_downgrade+0x980/0x980 [ 27.932749] ? selinux_socket_setsockopt+0x80/0x80 [ 27.937652] ? lock_release+0xa40/0xa40 [ 27.941615] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 27.947485] ? __check_object_size+0x25d/0x4f0 [ 27.952046] ? handle_mm_fault+0x410/0x8d0 [ 27.956263] ? __might_sleep+0x95/0x190 [ 27.960224] ? security_socket_connect+0x89/0xb0 [ 27.964960] SYSC_connect+0x213/0x4a0 [ 27.968739] ? SYSC_bind+0x410/0x410 [ 27.972443] ? do_page_fault+0xee/0x720 [ 27.976397] ? __do_page_fault+0xc90/0xc90 [ 27.980622] ? sock_map_fd+0x53/0x90 [ 27.984316] ? SyS_socket+0x12d/0x1d0 [ 27.988095] ? entry_SYSCALL_64_fastpath+0x5/0xa0 [ 27.992917] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 27.997920] SyS_connect+0x24/0x30 [ 28.001438] entry_SYSCALL_64_fastpath+0x29/0xa0 [ 28.006177] RIP: 0033:0x440879 [ 28.009349] RSP: 002b:00007ffc757de308 EFLAGS: 00000207 ORIG_RAX: 000000000000002a [ 28.017049] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000440879 [ 28.024298] RDX: 000000000000002e RSI: 00000000205fafd2 RDI: 0000000000000004 [ 28.031544] RBP: 0000000000006caa R08: 0000000000000000 R09: 0000000000000000 [ 28.038798] R10: 0000000000000000 R11: 0000000000000207 R12: 0000000000000000 [ 28.046046] R13: 0000000000401d70 R14: 0000000000000000 R15: 0000000000000000 [ 28.053306] [ 28.054912] Allocated by task 4194: [ 28.058522] save_stack+0x43/0xd0 [ 28.061961] kasan_kmalloc+0xad/0xe0 [ 28.065656] kasan_slab_alloc+0x12/0x20 [ 28.069603] kmem_cache_alloc+0x12e/0x760 [ 28.073722] sk_prot_alloc+0x65/0x2a0 [ 28.077492] sk_alloc+0x105/0x1440 [ 28.081006] inet6_create+0x44d/0x10f0 [ 28.084873] __sock_create+0x4d4/0x850 [ 28.088731] SyS_socket+0xeb/0x1d0 [ 28.092248] entry_SYSCALL_64_fastpath+0x29/0xa0 [ 28.096973] [ 28.098574] Freed by task 4198: [ 28.101826] save_stack+0x43/0xd0 [ 28.105250] kasan_slab_free+0x71/0xc0 [ 28.109109] kmem_cache_free+0x83/0x2a0 [ 28.113062] __sk_destruct+0x628/0x920 [ 28.116926] rcu_process_callbacks+0xd6c/0x17f0 [ 28.121583] __do_softirq+0x2d7/0xb85 [ 28.125352] [ 28.126952] The buggy address belongs to the object at ffff8801d7d308c0 [ 28.126952] which belongs to the cache UDPv6 of size 1664 [ 28.139147] The buggy address is located 552 bytes inside of [ 28.139147] 1664-byte region [ffff8801d7d308c0, ffff8801d7d30f40) [ 28.151078] The buggy address belongs to the page: [ 28.155984] page:ffffea00075f4c00 count:1 mapcount:0 mapping:ffff8801d7d301c0 index:0x0 [ 28.164116] flags: 0x2fffc0000000100(slab) [ 28.168335] raw: 02fffc0000000100 ffff8801d7d301c0 0000000000000000 0000000100000002 [ 28.176200] raw: ffffea00076069e0 ffffea000760b420 ffff8801d32e3cc0 0000000000000000 [ 28.184061] page dumped because: kasan: bad access detected [ 28.189746] [ 28.191346] Memory state around the buggy address: [ 28.196248] ffff8801d7d30980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.203586] ffff8801d7d30a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.210924] >ffff8801d7d30a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.218254] ^ [ 28.224980] ffff8801d7d30b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.232315] ffff8801d7d30b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.239645] ================================================================== [ 28.246977] Disabling lock debugging due to kernel taint [ 28.252434] Kernel panic - not syncing: panic_on_warn set ... [ 28.252434] [ 28.259785] CPU: 1 PID: 4198 Comm: syzkaller636167 Tainted: G B 4.15.0-rc8+ #202 [ 28.268509] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.277837] Call Trace: [ 28.280407] dump_stack+0x194/0x257 [ 28.284021] ? arch_local_irq_restore+0x53/0x53 [ 28.288674] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 28.293404] ? vsnprintf+0x1ed/0x1900 [ 28.297184] ? pppol2tp_connect+0x1a00/0x1dd0 [ 28.301653] panic+0x1e4/0x41c [ 28.304821] ? refcount_error_report+0x214/0x214 [ 28.309560] ? add_taint+0x1c/0x50 [ 28.313079] ? add_taint+0x1c/0x50 [ 28.316593] ? pppol2tp_connect+0x1a91/0x1dd0 [ 28.321066] kasan_end_report+0x50/0x50 [ 28.325016] kasan_report+0x144/0x340 [ 28.328802] __asan_report_load8_noabort+0x14/0x20 [ 28.333713] pppol2tp_connect+0x1a91/0x1dd0 [ 28.338029] ? pppol2tp_recv_payload_hook+0x1b0/0x1b0 [ 28.343200] ? selinux_netlbl_socket_connect+0x76/0x1b0 [ 28.348550] ? selinux_socket_connect+0x311/0x730 [ 28.353369] ? lock_downgrade+0x980/0x980 [ 28.357503] ? lock_downgrade+0x980/0x980 [ 28.361630] ? selinux_socket_setsockopt+0x80/0x80 [ 28.366530] ? lock_release+0xa40/0xa40 [ 28.370483] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 28.376341] ? __check_object_size+0x25d/0x4f0 [ 28.380898] ? handle_mm_fault+0x410/0x8d0 [ 28.385116] ? __might_sleep+0x95/0x190 [ 28.389077] ? security_socket_connect+0x89/0xb0 [ 28.393816] SYSC_connect+0x213/0x4a0 [ 28.397590] ? SYSC_bind+0x410/0x410 [ 28.401288] ? do_page_fault+0xee/0x720 [ 28.405234] ? __do_page_fault+0xc90/0xc90 [ 28.409444] ? sock_map_fd+0x53/0x90 [ 28.413129] ? SyS_socket+0x12d/0x1d0 [ 28.416906] ? entry_SYSCALL_64_fastpath+0x5/0xa0 [ 28.421724] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 28.426718] SyS_connect+0x24/0x30 [ 28.430231] entry_SYSCALL_64_fastpath+0x29/0xa0 [ 28.434957] RIP: 0033:0x440879 [ 28.438117] RSP: 002b:00007ffc757de308 EFLAGS: 00000207 ORIG_RAX: 000000000000002a [ 28.445796] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000440879 [ 28.453061] RDX: 000000000000002e RSI: 00000000205fafd2 RDI: 0000000000000004 [ 28.460312] RBP: 0000000000006caa R08: 0000000000000000 R09: 0000000000000000 [ 28.467560] R10: 0000000000000000 R11: 0000000000000207 R12: 0000000000000000 [ 28.474802] R13: 0000000000401d70 R14: 0000000000000000 R15: 0000000000000000 [ 28.482531] Dumping ftrace buffer: [ 28.486045] (ftrace buffer empty) [ 28.489725] Kernel Offset: disabled [ 28.493333] Rebooting in 86400 seconds..