[....] Starting enhanced syslogd: rsyslogd[ 13.725852] audit: type=1400 audit(1518169080.190:4): avc: denied { syslog } for pid=3644 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[1G[[32m ok [39;49m8[?25h[?0c. Starting mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.15.204' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 26.559237] ================================================================== [ 26.566726] BUG: KASAN: use-after-free in ip6_xmit+0x1b44/0x1b70 [ 26.572841] Read of size 8 at addr ffff8801b7004298 by task syzkaller518991/3800 [ 26.580346] [ 26.581950] CPU: 1 PID: 3800 Comm: syzkaller518991 Not tainted 4.9.80-g20c8a00 #38 [ 26.589627] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 26.598953] ffff8801d7887698 ffffffff81d94b69 ffffea0006dc0100 ffff8801b7004298 [ 26.606963] 0000000000000000 ffff8801b7004298 0000000000000040 ffff8801d78876d0 [ 26.614936] ffffffff8153e093 ffff8801b7004298 0000000000000008 0000000000000000 [ 26.622913] Call Trace: [ 26.625471] [] dump_stack+0xc1/0x128 [ 26.630811] [] print_address_description+0x73/0x280 [ 26.637455] [] kasan_report+0x275/0x360 [ 26.643058] [] ? ip6_xmit+0x1b44/0x1b70 [ 26.648659] [] __asan_report_load8_noabort+0x14/0x20 [ 26.655382] [] ip6_xmit+0x1b44/0x1b70 [ 26.660803] [] ? save_stack_trace+0x16/0x20 [ 26.666751] [] ? save_trace+0xe0/0x270 [ 26.672264] [] ? register_lock_class+0xb53/0x1340 [ 26.678727] [] ? ip6_finish_output2+0x1d20/0x1d20 [ 26.685193] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 26.692185] [] ? __lock_is_held+0xa1/0xf0 [ 26.697956] [] ? ipv4_dst_check+0x111/0x160 [ 26.703897] [] ? __sk_dst_check+0x10e/0x240 [ 26.709835] [] ? inet6_csk_route_socket+0x61c/0xc50 [ 26.716481] [] inet6_csk_xmit+0x27d/0x4d0 [ 26.722248] [] ? inet6_csk_xmit+0x100/0x4d0 [ 26.728202] [] ? inet6_csk_update_pmtu+0x160/0x160 [ 26.734758] [] l2tp_xmit_skb+0xcdc/0xf50 [ 26.740437] [] pppol2tp_sendmsg+0x5c0/0x7a0 [ 26.746377] [] ? selinux_socket_sendmsg+0x3f/0x50 [ 26.752841] [] ? pppol2tp_release+0x2e0/0x2e0 [ 26.758964] [] sock_sendmsg+0xca/0x110 [ 26.764484] [] sock_write_iter+0x226/0x3b0 [ 26.770352] [] ? avc_has_perm_noaudit+0x450/0x450 [ 26.776823] [] ? sock_sendmsg+0x110/0x110 [ 26.782599] [] ? iov_iter_init+0xaf/0x1d0 [ 26.788372] [] __vfs_write+0x4bf/0x680 [ 26.793878] [] ? do_iter_readv_writev+0x400/0x400 [ 26.800340] [] ? selinux_file_permission+0x82/0x460 [ 26.806973] [] ? rw_verify_area+0xe5/0x2b0 [ 26.812826] [] vfs_write+0x189/0x530 [ 26.818155] [] SyS_write+0xd9/0x1b0 [ 26.823414] [] ? SyS_read+0x1b0/0x1b0 [ 26.828834] [] ? do_fast_syscall_32+0xcf/0x890 [ 26.835033] [] ? SyS_read+0x1b0/0x1b0 [ 26.840453] [] do_fast_syscall_32+0x2f7/0x890 [ 26.846569] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 26.853204] [] entry_SYSENTER_compat+0x74/0x83 [ 26.859417] [ 26.861017] Allocated by task 3778: [ 26.864614] save_stack_trace+0x16/0x20 [ 26.868562] save_stack+0x43/0xd0 [ 26.871984] kasan_kmalloc+0xad/0xe0 [ 26.875666] kasan_slab_alloc+0x12/0x20 [ 26.879611] kmem_cache_alloc+0xba/0x290 [ 26.883671] dst_alloc+0x11f/0x1a0 [ 26.887397] rt_dst_alloc+0x78/0x430 [ 26.891094] __ip_route_output_key_hash+0xa4e/0x23e0 [ 26.896174] __ip4_datagram_connect+0xa17/0x1160 [ 26.900902] __ip6_datagram_connect+0x6f9/0xdf0 [ 26.905550] ip6_datagram_connect+0x2f/0x50 [ 26.909839] inet_dgram_connect+0x16b/0x1f0 [ 26.914141] SYSC_connect+0x1b6/0x310 [ 26.917908] SyS_connect+0x24/0x30 [ 26.921416] entry_SYSCALL_64_fastpath+0x29/0xe8 [ 26.926147] [ 26.927743] Freed by task 17: [ 26.930817] save_stack_trace+0x16/0x20 [ 26.934760] save_stack+0x43/0xd0 [ 26.938192] kasan_slab_free+0x72/0xc0 [ 26.942581] kmem_cache_free+0xc7/0x300 [ 26.946537] dst_destroy+0x1fd/0x360 [ 26.950220] dst_destroy_rcu+0x15/0x40 [ 26.954083] rcu_process_callbacks+0x898/0x1300 [ 26.958734] __do_softirq+0x206/0x951 [ 26.962500] [ 26.964097] The buggy address belongs to the object at ffff8801b7004280 [ 26.964097] which belongs to the cache ip_dst_cache of size 216 [ 26.976807] The buggy address is located 24 bytes inside of [ 26.976807] 216-byte region [ffff8801b7004280, ffff8801b7004358) [ 26.988648] The buggy address belongs to the page: [ 26.993552] page:ffffea0006dc0100 count:1 mapcount:0 mapping: (null) index:0x0 [ 27.001799] flags: 0x8000000000000080(slab) [ 27.006085] page dumped because: kasan: bad access detected [ 27.011758] [ 27.013354] Memory state around the buggy address: [ 27.018249] ffff8801b7004180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 27.025574] ffff8801b7004200: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc [ 27.032901] >ffff8801b7004280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 27.040226] ^ [ 27.044341] ffff8801b7004300: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc [ 27.051666] ffff8801b7004380: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 [ 27.058990] ================================================================== [ 27.066314] Disabling lock debugging due to kernel taint [ 27.071765] Kernel panic - not syncing: panic_on_warn set ... [ 27.071765] [ 27.079099] CPU: 1 PID: 3800 Comm: syzkaller518991 Tainted: G B 4.9.80-g20c8a00 #38 [ 27.087985] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 27.097312] ffff8801d78875f0 ffffffff81d94b69 ffffffff841970af ffff8801d78876c8 [ 27.105305] 0000000000000000 ffff8801b7004298 0000000000000040 ffff8801d78876b8 [ 27.113272] ffffffff8142f541 0000000041b58ab3 ffffffff8418ab20 ffffffff8142f385 [ 27.121239] Call Trace: [ 27.123803] [] dump_stack+0xc1/0x128 [ 27.129136] [] panic+0x1bc/0x3a8 [ 27.134122] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 [ 27.142321] [] ? add_taint+0x1c/0x50 [ 27.147652] [] kasan_end_report+0x50/0x50 [ 27.153416] [] kasan_report+0x167/0x360 [ 27.159006] [] ? ip6_xmit+0x1b44/0x1b70 [ 27.164599] [] __asan_report_load8_noabort+0x14/0x20 [ 27.171337] [] ip6_xmit+0x1b44/0x1b70 [ 27.176754] [] ? save_stack_trace+0x16/0x20 [ 27.182708] [] ? save_trace+0xe0/0x270 [ 27.188213] [] ? register_lock_class+0xb53/0x1340 [ 27.194671] [] ? ip6_finish_output2+0x1d20/0x1d20 [ 27.201132] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 27.208111] [] ? __lock_is_held+0xa1/0xf0 [ 27.213875] [] ? ipv4_dst_check+0x111/0x160 [ 27.219812] [] ? __sk_dst_check+0x10e/0x240 [ 27.225750] [] ? inet6_csk_route_socket+0x61c/0xc50 [ 27.232386] [] inet6_csk_xmit+0x27d/0x4d0 [ 27.238148] [] ? inet6_csk_xmit+0x100/0x4d0 [ 27.244084] [] ? inet6_csk_update_pmtu+0x160/0x160 [ 27.250631] [] l2tp_xmit_skb+0xcdc/0xf50 [ 27.256325] [] pppol2tp_sendmsg+0x5c0/0x7a0 [ 27.262267] [] ? selinux_socket_sendmsg+0x3f/0x50 [ 27.268725] [] ? pppol2tp_release+0x2e0/0x2e0 [ 27.274839] [] sock_sendmsg+0xca/0x110 [ 27.280346] [] sock_write_iter+0x226/0x3b0 [ 27.286209] [] ? avc_has_perm_noaudit+0x450/0x450 [ 27.292669] [] ? sock_sendmsg+0x110/0x110 [ 27.298434] [] ? iov_iter_init+0xaf/0x1d0 [ 27.304200] [] __vfs_write+0x4bf/0x680 [ 27.309708] [] ? do_iter_readv_writev+0x400/0x400 [ 27.316166] [] ? selinux_file_permission+0x82/0x460 [ 27.322797] [] ? rw_verify_area+0xe5/0x2b0 [ 27.328648] [] vfs_write+0x189/0x530 [ 27.333977] [] SyS_write+0xd9/0x1b0 [ 27.339220] [] ? SyS_read+0x1b0/0x1b0 [ 27.344640] [] ? do_fast_syscall_32+0xcf/0x890 [ 27.350850] [] ? SyS_read+0x1b0/0x1b0 [ 27.356270] [] do_fast_syscall_32+0x2f7/0x890 [ 27.362394] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 27.369028] [] entry_SYSENTER_compat+0x74/0x83 [ 27.375627] Dumping ftrace buffer: [ 27.379145] (ftrace buffer empty) [ 27.382825] Kernel Offset: disabled [ 27.386423] Rebooting in 86400 seconds..