[....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 15.525705] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.611718] random: sshd: uninitialized urandom read (32 bytes read) [ 20.928972] random: sshd: uninitialized urandom read (32 bytes read) [ 21.764365] random: sshd: uninitialized urandom read (32 bytes read) [ 40.075093] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.31' (ECDSA) to the list of known hosts. [ 45.508613] random: sshd: uninitialized urandom read (32 bytes read) 2018/05/26 03:52:13 parsed 1 programs 2018/05/26 03:52:13 executed programs: 0 [ 46.089884] IPVS: Creating netns size=2536 id=1 [ 46.187259] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 46.199187] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 46.256522] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 46.268642] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 46.315588] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 46.327416] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 46.339463] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 46.353698] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 46.905044] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 46.938591] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 46.944885] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 46.953222] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 48.009317] ================================================================== [ 48.016715] BUG: KASAN: use-after-free in tcp_connect+0x2633/0x2fa0 [ 48.023100] Read of size 4 at addr ffff8801c5a4c7a8 by task syz-executor0/4176 [ 48.030444] [ 48.032051] CPU: 1 PID: 4176 Comm: syz-executor0 Not tainted 4.9.103-g70c65e4 #37 [ 48.039645] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.049118] ffff8801b68c7920 ffffffff81eb3469 ffffea0007169300 ffff8801c5a4c7a8 [ 48.057448] 0000000000000000 ffff8801c5a4c7a8 ffff8801b86e26d8 ffff8801b68c7958 [ 48.065470] ffffffff815676bb ffff8801c5a4c7a8 0000000000000004 0000000000000000 [ 48.073494] Call Trace: [ 48.076072] [] dump_stack+0xc1/0x128 [ 48.081427] [] print_address_description+0x6c/0x234 [ 48.088071] [] kasan_report.cold.6+0x242/0x2fe [ 48.094298] [] ? tcp_connect+0x2633/0x2fa0 [ 48.100181] [] __asan_report_load4_noabort+0x14/0x20 [ 48.106911] [] tcp_connect+0x2633/0x2fa0 [ 48.112607] [] ? tcp_push_one+0xe0/0xe0 [ 48.118214] [] ? dst_release+0x70/0xb0 [ 48.123757] [] tcp_v4_connect+0x19f0/0x1c20 [ 48.129726] [] ? tcp_v4_inbound_md5_hash+0x3f0/0x3f0 [ 48.136478] [] ? selinux_socket_connect+0x167/0x4a0 [ 48.143142] [] __inet_stream_connect+0x6e0/0xbf0 [ 48.149528] [] ? mark_held_locks+0xc7/0x130 [ 48.155487] [] ? inet_bind+0x8b0/0x8b0 [ 48.161008] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 48.167828] [] ? lock_sock_nested+0x90/0x120 [ 48.173880] [] ? trace_hardirqs_on+0xd/0x10 [ 48.179836] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 48.186131] [] inet_stream_connect+0x55/0xa0 [ 48.192167] [] SYSC_connect+0x1b8/0x300 [ 48.197864] [] ? SYSC_bind+0x280/0x280 [ 48.203387] [] ? compat_SyS_get_robust_list+0x310/0x310 [ 48.210380] [] ? _raw_spin_unlock_irq+0x27/0x50 [ 48.216682] [] SyS_connect+0x24/0x30 [ 48.222021] [] ? SyS_accept+0x30/0x30 [ 48.227450] [] do_fast_syscall_32+0x2f7/0x870 [ 48.233581] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 48.240222] [] entry_SYSENTER_compat+0x90/0xa2 [ 48.246422] [ 48.248024] Allocated by task 4175: [ 48.251635] save_stack_trace+0x16/0x20 [ 48.255593] save_stack+0x43/0xd0 [ 48.259029] kasan_kmalloc+0xc7/0xe0 [ 48.262717] kasan_slab_alloc+0x12/0x20 [ 48.266682] kmem_cache_alloc+0xbe/0x290 [ 48.270739] __alloc_skb+0xe6/0x600 [ 48.274349] sk_stream_alloc_skb+0xa3/0x5d0 [ 48.278677] tcp_sendmsg+0xe57/0x3040 [ 48.282465] inet_sendmsg+0x203/0x4d0 [ 48.286242] sock_sendmsg+0xcc/0x110 [ 48.290108] SYSC_sendto+0x21c/0x370 [ 48.293803] SyS_sendto+0x40/0x50 [ 48.297231] do_fast_syscall_32+0x2f7/0x870 [ 48.301526] entry_SYSENTER_compat+0x90/0xa2 [ 48.305906] [ 48.307510] Freed by task 4176: [ 48.310767] save_stack_trace+0x16/0x20 [ 48.314716] save_stack+0x43/0xd0 [ 48.318143] kasan_slab_free+0x72/0xc0 [ 48.322037] kmem_cache_free+0xbe/0x310 [ 48.325986] kfree_skbmem+0x7c/0x100 [ 48.329674] __kfree_skb+0x1d/0x20 [ 48.333200] tcp_connect+0xaaf/0x2fa0 [ 48.336981] tcp_v4_connect+0x19f0/0x1c20 [ 48.341109] __inet_stream_connect+0x6e0/0xbf0 [ 48.345673] inet_stream_connect+0x55/0xa0 [ 48.349883] SYSC_connect+0x1b8/0x300 [ 48.353657] SyS_connect+0x24/0x30 [ 48.357173] do_fast_syscall_32+0x2f7/0x870 [ 48.361471] entry_SYSENTER_compat+0x90/0xa2 [ 48.365858] [ 48.367461] The buggy address belongs to the object at ffff8801c5a4c780 [ 48.367461] which belongs to the cache skbuff_fclone_cache of size 456 [ 48.380798] The buggy address is located 40 bytes inside of [ 48.380798] 456-byte region [ffff8801c5a4c780, ffff8801c5a4c948) [ 48.392563] The buggy address belongs to the page: [ 48.397566] page:ffffea0007169300 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 48.407761] flags: 0x8000000000004080(slab|head) [ 48.412489] page dumped because: kasan: bad access detected [ 48.418168] [ 48.419773] Memory state around the buggy address: [ 48.424679] ffff8801c5a4c680: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc [ 48.432014] ffff8801c5a4c700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 48.439369] >ffff8801c5a4c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.446714] ^ [ 48.451368] ffff8801c5a4c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.458711] ffff8801c5a4c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.466058] ================================================================== [ 48.473399] Disabling lock debugging due to kernel taint [ 48.479483] Kernel panic - not syncing: panic_on_warn set ... [ 48.479483] [ 48.486862] CPU: 1 PID: 4176 Comm: syz-executor0 Tainted: G B 4.9.103-g70c65e4 #37 [ 48.495681] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.505035] ffff8801b68c7880 ffffffff81eb3469 ffffffff843c5d75 00000000ffffffff [ 48.513027] 0000000000000000 0000000000000001 ffff8801b86e26d8 ffff8801b68c7940 [ 48.521021] ffffffff81421aa5 0000000041b58ab3 ffffffff843b94a8 ffffffff814218e6 [ 48.529030] Call Trace: [ 48.531596] [] dump_stack+0xc1/0x128 [ 48.536937] [] panic+0x1bf/0x3bc [ 48.541935] [] ? add_taint.cold.6+0x16/0x16 [ 48.547882] [] ? ___preempt_schedule+0x16/0x18 [ 48.554104] [] kasan_end_report+0x47/0x4f [ 48.559878] [] kasan_report.cold.6+0x76/0x2fe [ 48.565999] [] ? tcp_connect+0x2633/0x2fa0 [ 48.571859] [] __asan_report_load4_noabort+0x14/0x20 [ 48.578585] [] tcp_connect+0x2633/0x2fa0 [ 48.584270] [] ? tcp_push_one+0xe0/0xe0 [ 48.589869] [] ? dst_release+0x70/0xb0 [ 48.595390] [] tcp_v4_connect+0x19f0/0x1c20 [ 48.601334] [] ? tcp_v4_inbound_md5_hash+0x3f0/0x3f0 [ 48.608103] [] ? selinux_socket_connect+0x167/0x4a0 [ 48.614743] [] __inet_stream_connect+0x6e0/0xbf0 [ 48.621144] [] ? mark_held_locks+0xc7/0x130 [ 48.627093] [] ? inet_bind+0x8b0/0x8b0 [ 48.632609] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 48.639431] [] ? lock_sock_nested+0x90/0x120 [ 48.645481] [] ? trace_hardirqs_on+0xd/0x10 [ 48.651430] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 48.657723] [] inet_stream_connect+0x55/0xa0 [ 48.663761] [] SYSC_connect+0x1b8/0x300 [ 48.669361] [] ? SYSC_bind+0x280/0x280 [ 48.674878] [] ? compat_SyS_get_robust_list+0x310/0x310 [ 48.681880] [] ? _raw_spin_unlock_irq+0x27/0x50 [ 48.688176] [] SyS_connect+0x24/0x30 [ 48.693529] [] ? SyS_accept+0x30/0x30 [ 48.698959] [] do_fast_syscall_32+0x2f7/0x870 [ 48.705083] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 48.711727] [] entry_SYSENTER_compat+0x90/0xa2 [ 48.718473] Dumping ftrace buffer: [ 48.721999] (ftrace buffer empty) [ 48.725683] Kernel Offset: disabled [ 48.729285] Rebooting in 86400 seconds..