[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.621827] random: sshd: uninitialized urandom read (32 bytes read, 31 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 24.787660] random: sshd: uninitialized urandom read (32 bytes read, 36 bits of entropy available) [ 25.183560] random: sshd: uninitialized urandom read (32 bytes read, 36 bits of entropy available) [ 26.206203] random: nonblocking pool is initialized Warning: Permanently added '10.128.10.15' (ECDSA) to the list of known hosts. 2018/06/01 19:58:27 parsed 1 programs 2018/06/01 19:58:27 executed programs: 0 [ 32.462762] IPVS: Creating netns size=2552 id=1 [ 32.643766] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.659593] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.742741] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.756865] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 32.841447] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 32.857406] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 32.873725] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 32.890824] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.609438] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 33.649723] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 34.901708] ================================================================== [ 34.909094] BUG: KASAN: use-after-free in tcp_write_xmit+0x3fc2/0x4cb0 [ 34.915731] Read of size 2 at addr ffff8800bab66a30 by task syz-executor0/4104 [ 34.923059] [ 34.924662] CPU: 0 PID: 4104 Comm: syz-executor0 Not tainted 4.4.135-ge75204c #53 [ 34.932251] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.941589] 0000000000000000 05ea7f6aa19870db ffff8801d826f700 ffffffff81e0ed0d [ 34.949600] ffffea0002ead980 ffff8800bab66a30 0000000000000000 ffff8800bab66a30 [ 34.957587] dffffc0000000000 ffff8801d826f738 ffffffff81515946 ffff8800bab66a30 [ 34.965580] Call Trace: [ 34.968146] [] dump_stack+0xc1/0x124 [ 34.973486] [] print_address_description+0x6c/0x216 [ 34.980140] [] kasan_report.cold.7+0x175/0x2f7 [ 34.986346] [] ? tcp_write_xmit+0x3fc2/0x4cb0 [ 34.992464] [] __asan_report_load2_noabort+0x14/0x20 [ 34.999223] [] tcp_write_xmit+0x3fc2/0x4cb0 [ 35.005170] [] ? _raw_spin_unlock_irqrestore+0x45/0x70 [ 35.012074] [] ? finish_wait+0xfd/0x180 [ 35.017682] [] ? sk_stream_wait_memory+0x917/0xcb0 [ 35.024235] [] __tcp_push_pending_frames+0xa0/0x290 [ 35.030875] [] tcp_push+0x3e2/0x5a0 [ 35.036124] [] tcp_sendmsg+0x1ac1/0x2b00 [ 35.041808] [] ? tcp_sendpage+0x1840/0x1840 [ 35.047757] [] ? inet_sendmsg+0x143/0x4d0 [ 35.053527] [] inet_sendmsg+0x203/0x4d0 [ 35.059122] [] ? inet_sendmsg+0x73/0x4d0 [ 35.064804] [] ? inet_recvmsg+0x4c0/0x4c0 [ 35.070581] [] sock_sendmsg+0xcc/0x110 [ 35.076117] [] sock_write_iter+0x223/0x3b0 [ 35.081974] [] ? sock_sendmsg+0x110/0x110 [ 35.087747] [] ? iov_iter_init+0xaf/0x1d0 [ 35.093530] [] __vfs_write+0x30d/0x3f0 [ 35.099040] [] ? __vfs_read+0x3e0/0x3e0 [ 35.104638] [] ? selinux_file_permission+0x2f2/0x450 [ 35.111364] [] ? rw_verify_area+0x100/0x300 [ 35.117309] [] vfs_write+0x191/0x4e0 [ 35.122658] [] SyS_write+0xd9/0x1c0 [ 35.127918] [] ? SyS_read+0x1c0/0x1c0 [ 35.133342] [] ? do_fast_syscall_32+0xdb/0x8b0 [ 35.139545] [] ? SyS_read+0x1c0/0x1c0 [ 35.144976] [] do_fast_syscall_32+0x326/0x8b0 [ 35.151096] [] sysenter_flags_fixed+0xd/0x17 [ 35.157126] [ 35.158728] Allocated by task 4104: [ 35.162324] [] save_stack_trace+0x26/0x50 [ 35.168214] [] save_stack+0x43/0xd0 [ 35.173580] [] kasan_kmalloc+0xc7/0xe0 [ 35.179219] [] kasan_slab_alloc+0x12/0x20 [ 35.185106] [] kmem_cache_alloc+0xbe/0x2a0 [ 35.191082] [] __alloc_skb+0xe6/0x600 [ 35.196644] [] sk_stream_alloc_skb+0xa3/0x5d0 [ 35.202897] [] tcp_sendmsg+0xd34/0x2b00 [ 35.208623] [] inet_sendmsg+0x203/0x4d0 [ 35.214359] [] sock_sendmsg+0xcc/0x110 [ 35.220012] [] sock_write_iter+0x223/0x3b0 [ 35.225992] [] __vfs_write+0x30d/0x3f0 [ 35.231631] [] vfs_write+0x191/0x4e0 [ 35.237091] [] SyS_write+0xd9/0x1c0 [ 35.242460] [] do_fast_syscall_32+0x326/0x8b0 [ 35.248706] [] sysenter_flags_fixed+0xd/0x17 [ 35.254855] [ 35.256456] Freed by task 4106: [ 35.259703] [] save_stack_trace+0x26/0x50 [ 35.265590] [] save_stack+0x43/0xd0 [ 35.270959] [] kasan_slab_free+0x72/0xc0 [ 35.276761] [] kmem_cache_free+0xbe/0x340 [ 35.282665] [] kfree_skbmem+0xcf/0x100 [ 35.288317] [] __kfree_skb+0x1d/0x20 [ 35.293815] [] tcp_connect+0xb24/0x30c0 [ 35.299538] [] tcp_v4_connect+0xf31/0x1890 [ 35.305523] [] __inet_stream_connect+0x2a9/0xc30 [ 35.312032] [] inet_stream_connect+0x55/0xa0 [ 35.318183] [] SYSC_connect+0x1b8/0x300 [ 35.323900] [] SyS_connect+0x24/0x30 [ 35.329354] [] do_fast_syscall_32+0x326/0x8b0 [ 35.335603] [] sysenter_flags_fixed+0xd/0x17 [ 35.341753] [ 35.343355] The buggy address belongs to the object at ffff8800bab66a00 [ 35.343355] which belongs to the cache skbuff_fclone_cache of size 456 [ 35.356678] The buggy address is located 48 bytes inside of [ 35.356678] 456-byte region [ffff8800bab66a00, ffff8800bab66bc8) [ 35.368445] The buggy address belongs to the page: [ 35.389327] kernel tried to execute NX-protected page - exploit attempt? (uid: 0) [ 35.397218] BUG: unable to handle kernel paging request at ffff8801d4b65220 [ 35.404624] IP: [] 0xffff8801d4b65220 [ 35.410159] PGD 632d067 PUD 80000001c00001e3 [ 35.414991] Oops: 0011 [#1] PREEMPT SMP KASAN [ 35.420076] Dumping ftrace buffer: [ 35.423609] (ftrace buffer empty) [ 35.427304] Modules linked in: [ 35.431417] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.135-ge75204c #53 [ 35.438417] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.447771] task: ffff8801d9a41800 task.stack: ffff8801d9a50000 [ 35.453828] RIP: 0010:[] [] 0xffff8801d4b65220 [ 35.461766] RSP: 0018:ffff8801db307f08 EFLAGS: 00010046 [ 35.467208] RAX: ffff8801d4b65220 RBX: ffff8801d9a57cf8 RCX: 1ffffffff0942999 [ 35.474475] RDX: 1ffff1003a96ca3c RSI: ffff8801d9a57cf8 RDI: ffff8801d4b65180 [ 35.481751] RBP: ffff8801db307f70 R08: 0000000000000000 R09: 0000000000000001 [ 35.489020] R10: 0000000000000000 R11: ffff8801d9a41800 R12: ffff8801d4b65180 [ 35.496291] R13: ffff8801d9a57d90 R14: ffff8801d9a50000 R15: 0000000000000000 [ 35.503565] FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 [ 35.511814] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 35.517698] CR2: ffff8801d4b65220 CR3: 00000000b6141000 CR4: 00000000001606f0 [ 35.524998] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 35.532271] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 35.539542] Stack: [ 35.541692] ffffffff81015b06 ffff8801db307f40 ffff8801db307f58 ffffffff81e6e89b [ 35.549758] 0000000000000001 ffffffff83a08cc0 00000000000000a1 0000000000000001 [ 35.557822] ffff8801d9a57cf8 00000000000000a1 ffff8801d4b65180 00000000000000a1 [ 35.565877] Call Trace: [ 35.568447] [ 35.570508] [] ? handle_irq+0x256/0x390 [ 35.576451] [] ? check_preemption_disabled+0x3b/0x170 [ 35.583299] [] do_IRQ+0x89/0x1c0 [ 35.588329] [] common_interrupt+0xa0/0xa0 [ 35.594117] [ 35.596181] [] ? native_safe_halt+0x6/0x10 [ 35.602377] [] default_idle+0x55/0x3c0 [ 35.608032] [] arch_cpu_idle+0x10/0x20 [ 35.613574] [] default_idle_call+0x57/0x70 [ 35.619463] [] cpu_startup_entry+0x6af/0x780 [ 35.625528] [] ? call_cpuidle+0xe0/0xe0 [ 35.631173] [] start_secondary+0x324/0x400 [ 35.637068] [] ? set_cpu_sibling_map+0x1180/0x1180 [ 35.643657] Code: 00 00 00 80 d9 ea 02 00 ea ff ff 00 00 00 00 00 00 00 00 e0 9e aa 83 ff ff ff ff 00 6a b6 ba 00 88 ff ff c8 6b b6 ba 00 88 ff ff <60> 52 b6 d4 01 88 ff ff 07 cf 48 81 ff ff ff ff ff ff ff ff ff [ 35.671662] RIP [] 0xffff8801d4b65220 [ 35.677246] RSP [ 35.680864] CR2: ffff8801d4b65220 [ 35.684316] ---[ end trace 1335b8947e1f1a34 ]--- [ 35.689190] Kernel panic - not syncing: Fatal exception in interrupt [ 36.829555] Shutting down cpus with NMI [ 36.834296] Dumping ftrace buffer: [ 36.837814] (ftrace buffer empty) [ 36.841507] Kernel Offset: disabled [ 36.845105] Rebooting in 86400 seconds..