[....] Starting enhanced syslogd: rsyslogd[ 13.476772] audit: type=1400 audit(1516363997.482:5): avc: denied { syslog } for pid=3503 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 mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] 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: [ 18.483940] audit: type=1400 audit(1516364002.489:6): avc: denied { map } for pid=3644 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 '10.128.0.45' (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 [ 26.023247] audit: type=1400 audit(1516364010.029:7): avc: denied { map } for pid=3658 comm="syzkaller633491" path="/root/syzkaller633491352" 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 program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 27.889295] ================================================================== [ 27.896733] BUG: KASAN: use-after-free in pppol2tp_connect+0x1a97/0x1dd0 [ 27.903552] Read of size 8 at addr ffff8801d6d9e8e8 by task syzkaller633491/3977 [ 27.911057] [ 27.912660] CPU: 1 PID: 3977 Comm: syzkaller633491 Not tainted 4.15.0-rc8+ #268 [ 27.920077] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 27.929404] Call Trace: [ 27.931972] dump_stack+0x194/0x257 [ 27.935574] ? arch_local_irq_restore+0x53/0x53 [ 27.940217] ? show_regs_print_info+0x18/0x18 [ 27.944708] ? lock_release+0xa40/0xa40 [ 27.948668] ? pppol2tp_connect+0x1a97/0x1dd0 [ 27.953144] print_address_description+0x73/0x250 [ 27.957975] ? pppol2tp_connect+0x1a97/0x1dd0 [ 27.962448] kasan_report+0x25b/0x340 [ 27.966226] __asan_report_load8_noabort+0x14/0x20 [ 27.971138] pppol2tp_connect+0x1a97/0x1dd0 [ 27.975444] ? pppol2tp_recv_payload_hook+0x1b0/0x1b0 [ 27.980615] ? selinux_netlbl_socket_connect+0x76/0x1b0 [ 27.985957] ? selinux_socket_connect+0x311/0x730 [ 27.990773] ? lock_downgrade+0x980/0x980 [ 27.994891] ? lock_downgrade+0x980/0x980 [ 27.999027] ? selinux_socket_setsockopt+0x80/0x80 [ 28.003931] ? lock_release+0xa40/0xa40 [ 28.007880] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 28.013740] ? __check_object_size+0x25d/0x4f0 [ 28.018300] ? handle_mm_fault+0x410/0x8d0 [ 28.022514] ? __might_sleep+0x95/0x190 [ 28.026473] ? security_socket_connect+0x89/0xb0 [ 28.031206] SYSC_connect+0x213/0x4a0 [ 28.034981] ? SYSC_bind+0x410/0x410 [ 28.038677] ? do_page_fault+0xee/0x720 [ 28.042645] ? __do_page_fault+0xc90/0xc90 [ 28.046947] ? sock_map_fd+0x53/0x90 [ 28.050638] ? SyS_socket+0x12d/0x1d0 [ 28.054414] ? entry_SYSCALL_64_fastpath+0x5/0xa0 [ 28.059233] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 28.064228] SyS_connect+0x24/0x30 [ 28.067753] entry_SYSCALL_64_fastpath+0x29/0xa0 [ 28.072490] RIP: 0033:0x444809 [ 28.075659] RSP: 002b:00007ffd01c91c38 EFLAGS: 00000203 ORIG_RAX: 000000000000002a [ 28.083361] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444809 [ 28.090617] RDX: 000000000000002e RSI: 0000000020e92000 RDI: 0000000000000005 [ 28.097861] RBP: 0000000000006cec R08: 0000000000000000 R09: 0000000000000000 [ 28.105106] R10: 0000000000000000 R11: 0000000000000203 R12: 0000000000000000 [ 28.112360] R13: 0000000000402180 R14: 0000000000000000 R15: 0000000000000000 [ 28.119620] [ 28.121224] Allocated by task 3975: [ 28.124829] save_stack+0x43/0xd0 [ 28.128253] kasan_kmalloc+0xad/0xe0 [ 28.131939] kasan_slab_alloc+0x12/0x20 [ 28.135886] kmem_cache_alloc+0x12e/0x760 [ 28.140009] sk_prot_alloc+0x65/0x2a0 [ 28.143787] sk_alloc+0x105/0x1410 [ 28.147303] inet_create+0x47c/0xf50 [ 28.150993] __sock_create+0x4d4/0x850 [ 28.154857] SyS_socket+0xeb/0x1d0 [ 28.158381] entry_SYSCALL_64_fastpath+0x29/0xa0 [ 28.163106] [ 28.164707] Freed by task 3977: [ 28.167960] save_stack+0x43/0xd0 [ 28.171395] kasan_slab_free+0x71/0xc0 [ 28.175252] kmem_cache_free+0x83/0x2a0 [ 28.179198] __sk_destruct+0x622/0x910 [ 28.183061] sk_destruct+0x47/0x80 [ 28.186573] __sk_free+0x57/0x230 [ 28.190008] sk_free+0x2a/0x40 [ 28.193179] l2tp_session_free+0x21c/0x2b0 [ 28.197383] pppol2tp_session_destruct+0xd4/0x110 [ 28.202196] __sk_destruct+0xfd/0x910 [ 28.205977] sk_destruct+0x47/0x80 [ 28.209498] __sk_free+0x57/0x230 [ 28.212921] sk_free+0x2a/0x40 [ 28.216095] pppol2tp_put_sk+0x49/0x60 [ 28.219957] rcu_process_callbacks+0xd6c/0x17f0 [ 28.224596] __do_softirq+0x2d7/0xb85 [ 28.228368] [ 28.229968] The buggy address belongs to the object at ffff8801d6d9e6c0 [ 28.229968] which belongs to the cache UDP of size 1472 [ 28.241986] The buggy address is located 552 bytes inside of [ 28.241986] 1472-byte region [ffff8801d6d9e6c0, ffff8801d6d9ec80) [ 28.253929] The buggy address belongs to the page: [ 28.258831] page:ffffea00075b6780 count:1 mapcount:0 mapping:ffff8801d6d9e080 index:0x0 compound_mapcount: 0 [ 28.268789] flags: 0x2fffc0000008100(slab|head) [ 28.273431] raw: 02fffc0000008100 ffff8801d6d9e080 0000000000000000 0000000100000005 [ 28.281283] raw: ffffea0007612320 ffffea0007621f20 ffff8801d6fb0940 0000000000000000 [ 28.289131] page dumped because: kasan: bad access detected [ 28.294810] [ 28.296407] Memory state around the buggy address: [ 28.301320] ffff8801d6d9e780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.308652] ffff8801d6d9e800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.315987] >ffff8801d6d9e880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.323317] ^ [ 28.330042] ffff8801d6d9e900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.337383] ffff8801d6d9e980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.344711] ================================================================== [ 28.352044] Disabling lock debugging due to kernel taint [ 28.357628] Kernel panic - not syncing: panic_on_warn set ... [ 28.357628] [ 28.364982] CPU: 1 PID: 3977 Comm: syzkaller633491 Tainted: G B 4.15.0-rc8+ #268 [ 28.374348] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.383679] Call Trace: [ 28.386246] dump_stack+0x194/0x257 [ 28.389848] ? arch_local_irq_restore+0x53/0x53 [ 28.394492] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 28.399228] ? vsnprintf+0x1ed/0x1900 [ 28.403610] ? pppol2tp_connect+0x19a0/0x1dd0 [ 28.408078] panic+0x1e4/0x41c [ 28.411241] ? refcount_error_report+0x214/0x214 [ 28.415968] ? add_taint+0x1c/0x50 [ 28.419480] ? add_taint+0x1c/0x50 [ 28.422994] ? pppol2tp_connect+0x1a97/0x1dd0 [ 28.427472] kasan_end_report+0x50/0x50 [ 28.431422] kasan_report+0x144/0x340 [ 28.435193] __asan_report_load8_noabort+0x14/0x20 [ 28.440103] pppol2tp_connect+0x1a97/0x1dd0 [ 28.444400] ? pppol2tp_recv_payload_hook+0x1b0/0x1b0 [ 28.449565] ? selinux_netlbl_socket_connect+0x76/0x1b0 [ 28.454900] ? selinux_socket_connect+0x311/0x730 [ 28.459716] ? lock_downgrade+0x980/0x980 [ 28.463835] ? lock_downgrade+0x980/0x980 [ 28.467955] ? selinux_socket_setsockopt+0x80/0x80 [ 28.472855] ? lock_release+0xa40/0xa40 [ 28.476801] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 28.482664] ? __check_object_size+0x25d/0x4f0 [ 28.487220] ? handle_mm_fault+0x410/0x8d0 [ 28.491431] ? __might_sleep+0x95/0x190 [ 28.495382] ? security_socket_connect+0x89/0xb0 [ 28.500114] SYSC_connect+0x213/0x4a0 [ 28.503888] ? SYSC_bind+0x410/0x410 [ 28.507579] ? do_page_fault+0xee/0x720 [ 28.511526] ? __do_page_fault+0xc90/0xc90 [ 28.515736] ? sock_map_fd+0x53/0x90 [ 28.519420] ? SyS_socket+0x12d/0x1d0 [ 28.523195] ? entry_SYSCALL_64_fastpath+0x5/0xa0 [ 28.528013] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 28.533009] SyS_connect+0x24/0x30 [ 28.536526] entry_SYSCALL_64_fastpath+0x29/0xa0 [ 28.541253] RIP: 0033:0x444809 [ 28.544413] RSP: 002b:00007ffd01c91c38 EFLAGS: 00000203 ORIG_RAX: 000000000000002a [ 28.552093] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444809 [ 28.559347] RDX: 000000000000002e RSI: 0000000020e92000 RDI: 0000000000000005 [ 28.566588] RBP: 0000000000006cec R08: 0000000000000000 R09: 0000000000000000 [ 28.573840] R10: 0000000000000000 R11: 0000000000000203 R12: 0000000000000000 [ 28.581084] R13: 0000000000402180 R14: 0000000000000000 R15: 0000000000000000 [ 28.588785] Dumping ftrace buffer: [ 28.592313] (ftrace buffer empty) [ 28.596004] Kernel Offset: disabled [ 28.599612] Rebooting in 86400 seconds..