[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 32.743230] random: sshd: uninitialized urandom read (32 bytes read) [ 33.038275] kauditd_printk_skb: 10 callbacks suppressed [ 33.038283] audit: type=1400 audit(1569018463.558:35): avc: denied { map } for pid=6930 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 [ 33.094602] random: sshd: uninitialized urandom read (32 bytes read) [ 33.629464] random: sshd: uninitialized urandom read (32 bytes read) [ 38.132347] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.1.16' (ECDSA) to the list of known hosts. [ 43.797736] random: sshd: uninitialized urandom read (32 bytes read) [ 43.927604] audit: type=1400 audit(1569018474.448:36): avc: denied { map } for pid=6943 comm="syz-executor595" path="/root/syz-executor595332872" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 44.161095] IPVS: ftp: loaded support on port[0] = 21 [ 44.957593] chnl_net:caif_netlink_parms(): no params data found [ 44.988340] bridge0: port 1(bridge_slave_0) entered blocking state [ 44.995357] bridge0: port 1(bridge_slave_0) entered disabled state [ 45.002691] device bridge_slave_0 entered promiscuous mode [ 45.009869] bridge0: port 2(bridge_slave_1) entered blocking state [ 45.016375] bridge0: port 2(bridge_slave_1) entered disabled state [ 45.023369] device bridge_slave_1 entered promiscuous mode [ 45.037848] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 45.047235] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 45.065311] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 45.073227] team0: Port device team_slave_0 added [ 45.078771] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 45.086028] team0: Port device team_slave_1 added [ 45.091330] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready [ 45.098549] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready [ 45.152395] device hsr_slave_0 entered promiscuous mode [ 45.191134] device hsr_slave_1 entered promiscuous mode [ 45.230838] IPv6: ADDRCONF(NETDEV_UP): hsr_slave_0: link is not ready [ 45.237818] IPv6: ADDRCONF(NETDEV_UP): hsr_slave_1: link is not ready [ 45.253954] bridge0: port 2(bridge_slave_1) entered blocking state [ 45.260488] bridge0: port 2(bridge_slave_1) entered forwarding state [ 45.267562] bridge0: port 1(bridge_slave_0) entered blocking state [ 45.273998] bridge0: port 1(bridge_slave_0) entered forwarding state [ 45.302157] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 45.308257] 8021q: adding VLAN 0 to HW filter on device bond0 [ 45.317568] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 45.326728] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 45.346021] bridge0: port 1(bridge_slave_0) entered disabled state [ 45.353819] bridge0: port 2(bridge_slave_1) entered disabled state [ 45.366209] IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready [ 45.372746] 8021q: adding VLAN 0 to HW filter on device team0 [ 45.381462] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready [ 45.389177] bridge0: port 1(bridge_slave_0) entered blocking state [ 45.395655] bridge0: port 1(bridge_slave_0) entered forwarding state [ 45.404931] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready [ 45.413770] bridge0: port 2(bridge_slave_1) entered blocking state [ 45.420395] bridge0: port 2(bridge_slave_1) entered forwarding state [ 45.439349] hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network [ 45.449833] hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network [ 45.460926] IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready [ 45.468786] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 45.477303] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 45.485110] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready [ 45.493102] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready executing program [ 45.501307] IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready [ 45.508314] IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready [ 45.520629] IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready [ 45.530550] 8021q: adding VLAN 0 to HW filter on device batadv0 [ 45.671407] ================================================================== [ 45.679283] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x1ae/0x200 [ 45.686295] Read of size 2 at addr ffff8880965dad70 by task syz-executor595/6944 [ 45.693925] [ 45.695560] CPU: 1 PID: 6944 Comm: syz-executor595 Not tainted 4.14.145 #0 [ 45.702721] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.712199] Call Trace: [ 45.714924] dump_stack+0x138/0x197 [ 45.718545] ? tcp_init_tso_segs+0x1ae/0x200 [ 45.722978] print_address_description.cold+0x7c/0x1dc [ 45.728250] ? tcp_init_tso_segs+0x1ae/0x200 [ 45.732652] kasan_report.cold+0xa9/0x2af [ 45.736886] __asan_report_load2_noabort+0x14/0x20 [ 45.741830] tcp_init_tso_segs+0x1ae/0x200 [ 45.746058] ? tcp_tso_segs+0x7d/0x1c0 [ 45.749943] tcp_write_xmit+0x15e/0x4960 [ 45.754040] ? tcp_v4_md5_lookup+0x23/0x30 [ 45.758286] ? tcp_established_options+0x2c5/0x420 [ 45.763255] ? tcp_current_mss+0x1dc/0x2f0 [ 45.767488] ? __alloc_skb+0x3ee/0x500 [ 45.771373] __tcp_push_pending_frames+0xa6/0x260 [ 45.776242] tcp_send_fin+0x17e/0xc40 [ 45.780056] tcp_close+0xcc8/0xfb0 [ 45.783677] ? __sock_release+0x89/0x2b0 [ 45.787733] ? ip_mc_drop_socket+0x1d6/0x230 [ 45.792127] inet_release+0xec/0x1c0 [ 45.795845] __sock_release+0xce/0x2b0 [ 45.799731] ? __sock_release+0x2b0/0x2b0 [ 45.803870] sock_close+0x1b/0x30 [ 45.807470] __fput+0x275/0x7a0 [ 45.810745] ____fput+0x16/0x20 [ 45.814115] task_work_run+0x114/0x190 [ 45.818302] do_exit+0x7df/0x2c10 [ 45.821775] ? mm_update_next_owner+0x5d0/0x5d0 [ 45.826457] ? up_read+0x1a/0x40 [ 45.829897] ? __do_page_fault+0x358/0xb80 [ 45.834123] do_group_exit+0x111/0x330 [ 45.838013] SyS_exit_group+0x1d/0x20 [ 45.841915] ? do_group_exit+0x330/0x330 [ 45.846143] do_syscall_64+0x1e8/0x640 [ 45.850015] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 45.854869] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 45.860211] RIP: 0033:0x440b48 [ 45.863402] RSP: 002b:00007ffc10976638 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 45.871360] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b48 [ 45.878629] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 45.885960] RBP: 00000000004c6fd0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 45.893229] R10: 0000000020000800 R11: 0000000000000246 R12: 0000000000000001 [ 45.900493] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 45.907762] [ 45.909370] Allocated by task 6944: [ 45.912982] save_stack_trace+0x16/0x20 [ 45.917020] save_stack+0x45/0xd0 [ 45.920448] kasan_kmalloc+0xce/0xf0 [ 45.924232] kasan_slab_alloc+0xf/0x20 [ 45.928113] kmem_cache_alloc_node+0x144/0x780 [ 45.932676] __alloc_skb+0x9c/0x500 [ 45.936288] sk_stream_alloc_skb+0xb3/0x780 [ 45.940587] tcp_sendmsg_locked+0xf61/0x3200 [ 45.945160] tcp_sendmsg+0x30/0x50 [ 45.948687] inet_sendmsg+0x122/0x500 [ 45.953437] sock_sendmsg+0xce/0x110 [ 45.957142] SYSC_sendto+0x206/0x310 [ 45.960864] SyS_sendto+0x40/0x50 [ 45.964315] do_syscall_64+0x1e8/0x640 [ 45.968190] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 45.973476] [ 45.975088] Freed by task 6944: [ 45.978347] save_stack_trace+0x16/0x20 [ 45.982314] save_stack+0x45/0xd0 [ 45.986437] kasan_slab_free+0x75/0xc0 [ 45.990302] kmem_cache_free+0x83/0x2b0 [ 45.994342] kfree_skbmem+0x8d/0x120 [ 45.998032] __kfree_skb+0x1e/0x30 [ 46.001549] tcp_remove_empty_skb.part.0+0x231/0x2e0 [ 46.006641] tcp_sendmsg_locked+0x1ced/0x3200 [ 46.011127] tcp_sendmsg+0x30/0x50 [ 46.014646] inet_sendmsg+0x122/0x500 [ 46.018438] sock_sendmsg+0xce/0x110 [ 46.022130] SYSC_sendto+0x206/0x310 [ 46.025907] SyS_sendto+0x40/0x50 [ 46.029424] do_syscall_64+0x1e8/0x640 [ 46.033314] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 46.038484] [ 46.040092] The buggy address belongs to the object at ffff8880965dad40 [ 46.040092] which belongs to the cache skbuff_fclone_cache of size 472 [ 46.053521] The buggy address is located 48 bytes inside of [ 46.053521] 472-byte region [ffff8880965dad40, ffff8880965daf18) [ 46.065547] The buggy address belongs to the page: [ 46.070483] page:ffffea0002597680 count:1 mapcount:0 mapping:ffff8880965da0c0 index:0x0 [ 46.078617] flags: 0x1fffc0000000100(slab) [ 46.082840] raw: 01fffc0000000100 ffff8880965da0c0 0000000000000000 0000000100000006 [ 46.090700] raw: ffffea0002439fe0 ffff8880a9e80e48 ffff8880a9e81d80 0000000000000000 [ 46.098563] page dumped because: kasan: bad access detected [ 46.104251] [ 46.105868] Memory state around the buggy address: [ 46.111730] ffff8880965dac00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 46.119069] ffff8880965dac80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 46.126415] >ffff8880965dad00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 46.133749] ^ [ 46.140753] ffff8880965dad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.148095] ffff8880965dae00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.155441] ================================================================== [ 46.162792] Disabling lock debugging due to kernel taint [ 46.169482] Kernel panic - not syncing: panic_on_warn set ... [ 46.169482] [ 46.176859] CPU: 1 PID: 6944 Comm: syz-executor595 Tainted: G B 4.14.145 #0 [ 46.190904] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 46.200292] Call Trace: [ 46.202866] dump_stack+0x138/0x197 [ 46.206473] ? tcp_init_tso_segs+0x1ae/0x200 [ 46.210860] panic+0x1f2/0x426 [ 46.214118] ? add_taint.cold+0x16/0x16 [ 46.218089] ? ___preempt_schedule+0x16/0x18 [ 46.222484] kasan_end_report+0x47/0x4f [ 46.226613] kasan_report.cold+0x130/0x2af [ 46.230862] __asan_report_load2_noabort+0x14/0x20 [ 46.235773] tcp_init_tso_segs+0x1ae/0x200 [ 46.239984] ? tcp_tso_segs+0x7d/0x1c0 [ 46.243850] tcp_write_xmit+0x15e/0x4960 [ 46.247901] ? tcp_v4_md5_lookup+0x23/0x30 [ 46.252122] ? tcp_established_options+0x2c5/0x420 [ 46.257036] ? tcp_current_mss+0x1dc/0x2f0 [ 46.261260] ? __alloc_skb+0x3ee/0x500 [ 46.265271] __tcp_push_pending_frames+0xa6/0x260 [ 46.270102] tcp_send_fin+0x17e/0xc40 [ 46.273893] tcp_close+0xcc8/0xfb0 [ 46.277517] ? __sock_release+0x89/0x2b0 [ 46.281560] ? ip_mc_drop_socket+0x1d6/0x230 [ 46.285947] inet_release+0xec/0x1c0 [ 46.289656] __sock_release+0xce/0x2b0 [ 46.293520] ? __sock_release+0x2b0/0x2b0 [ 46.297643] sock_close+0x1b/0x30 [ 46.301073] __fput+0x275/0x7a0 [ 46.304429] ____fput+0x16/0x20 [ 46.307708] task_work_run+0x114/0x190 [ 46.311587] do_exit+0x7df/0x2c10 [ 46.315025] ? mm_update_next_owner+0x5d0/0x5d0 [ 46.319814] ? up_read+0x1a/0x40 [ 46.323200] ? __do_page_fault+0x358/0xb80 [ 46.327511] do_group_exit+0x111/0x330 [ 46.331389] SyS_exit_group+0x1d/0x20 [ 46.335173] ? do_group_exit+0x330/0x330 [ 46.339210] do_syscall_64+0x1e8/0x640 [ 46.343119] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 46.347979] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 46.353153] RIP: 0033:0x440b48 [ 46.356420] RSP: 002b:00007ffc10976638 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 46.364106] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b48 [ 46.371635] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 46.379068] RBP: 00000000004c6fd0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 46.386411] R10: 0000000020000800 R11: 0000000000000246 R12: 0000000000000001 [ 46.393659] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 46.402248] Kernel Offset: disabled [ 46.405872] Rebooting in 86400 seconds..