[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 29.974878] random: sshd: uninitialized urandom read (32 bytes read) [ 30.323399] kauditd_printk_skb: 9 callbacks suppressed [ 30.323407] audit: type=1400 audit(1568992660.616:35): avc: denied { map } for pid=6814 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 [ 30.378631] random: sshd: uninitialized urandom read (32 bytes read) [ 30.874407] random: sshd: uninitialized urandom read (32 bytes read) [ 46.496239] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.1.8' (ECDSA) to the list of known hosts. [ 52.021749] random: sshd: uninitialized urandom read (32 bytes read) [ 52.141322] audit: type=1400 audit(1568992682.436:36): avc: denied { map } for pid=6828 comm="syz-executor106" path="/root/syz-executor106226600" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 52.400912] IPVS: ftp: loaded support on port[0] = 21 [ 53.225195] chnl_net:caif_netlink_parms(): no params data found [ 53.254074] bridge0: port 1(bridge_slave_0) entered blocking state [ 53.260925] bridge0: port 1(bridge_slave_0) entered disabled state [ 53.267873] device bridge_slave_0 entered promiscuous mode [ 53.274806] bridge0: port 2(bridge_slave_1) entered blocking state [ 53.281433] bridge0: port 2(bridge_slave_1) entered disabled state [ 53.288377] device bridge_slave_1 entered promiscuous mode [ 53.302204] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 53.311111] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 53.326887] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 53.334206] team0: Port device team_slave_0 added [ 53.339573] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 53.346813] team0: Port device team_slave_1 added [ 53.352247] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready [ 53.359401] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready [ 53.412063] device hsr_slave_0 entered promiscuous mode [ 53.450421] device hsr_slave_1 entered promiscuous mode [ 53.500499] IPv6: ADDRCONF(NETDEV_UP): hsr_slave_0: link is not ready [ 53.507379] IPv6: ADDRCONF(NETDEV_UP): hsr_slave_1: link is not ready [ 53.520121] bridge0: port 2(bridge_slave_1) entered blocking state [ 53.526607] bridge0: port 2(bridge_slave_1) entered forwarding state [ 53.533761] bridge0: port 1(bridge_slave_0) entered blocking state [ 53.540158] bridge0: port 1(bridge_slave_0) entered forwarding state [ 53.566411] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 53.573268] 8021q: adding VLAN 0 to HW filter on device bond0 [ 53.581396] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 53.589375] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 53.599142] bridge0: port 1(bridge_slave_0) entered disabled state [ 53.606952] bridge0: port 2(bridge_slave_1) entered disabled state [ 53.616175] IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready [ 53.623524] 8021q: adding VLAN 0 to HW filter on device team0 [ 53.631536] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready [ 53.639234] bridge0: port 1(bridge_slave_0) entered blocking state [ 53.645618] bridge0: port 1(bridge_slave_0) entered forwarding state [ 53.654399] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready [ 53.662419] bridge0: port 2(bridge_slave_1) entered blocking state [ 53.668738] bridge0: port 2(bridge_slave_1) entered forwarding state [ 53.685965] hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network [ 53.697970] hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network [ 53.709615] IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready [ 53.717053] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 53.724946] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 53.732706] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready [ 53.740324] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready [ 53.748062] IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready [ 53.754906] IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready executing program [ 53.765927] IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready [ 53.775483] 8021q: adding VLAN 0 to HW filter on device batadv0 [ 53.921185] ================================================================== [ 53.928633] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x1ae/0x200 [ 53.935366] Read of size 2 at addr ffff888099bcda70 by task syz-executor106/6829 [ 53.943833] [ 53.945457] CPU: 0 PID: 6829 Comm: syz-executor106 Not tainted 4.14.145 #0 [ 53.952479] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 53.961990] Call Trace: [ 53.964843] dump_stack+0x138/0x197 [ 53.968557] ? tcp_init_tso_segs+0x1ae/0x200 [ 53.972951] print_address_description.cold+0x7c/0x1dc [ 53.978209] ? tcp_init_tso_segs+0x1ae/0x200 [ 53.982603] kasan_report.cold+0xa9/0x2af [ 53.986736] __asan_report_load2_noabort+0x14/0x20 [ 53.991646] tcp_init_tso_segs+0x1ae/0x200 [ 53.995856] ? tcp_tso_segs+0x7d/0x1c0 [ 53.999720] tcp_write_xmit+0x15e/0x4960 [ 54.003783] ? tcp_v4_md5_lookup+0x23/0x30 [ 54.008011] ? tcp_established_options+0x2c5/0x420 [ 54.012924] ? tcp_current_mss+0x1dc/0x2f0 [ 54.017259] ? __alloc_skb+0x3ee/0x500 [ 54.021136] __tcp_push_pending_frames+0xa6/0x260 [ 54.025965] tcp_send_fin+0x17e/0xc40 [ 54.029763] tcp_close+0xcc8/0xfb0 [ 54.033285] ? __sock_release+0x89/0x2b0 [ 54.037330] ? ip_mc_drop_socket+0x1d6/0x230 [ 54.041720] inet_release+0xec/0x1c0 [ 54.045426] __sock_release+0xce/0x2b0 [ 54.049419] ? __sock_release+0x2b0/0x2b0 [ 54.053575] sock_close+0x1b/0x30 [ 54.057011] __fput+0x275/0x7a0 [ 54.060277] ____fput+0x16/0x20 [ 54.063640] task_work_run+0x114/0x190 [ 54.067807] do_exit+0x7df/0x2c10 [ 54.071266] ? mm_update_next_owner+0x5d0/0x5d0 [ 54.075981] ? up_read+0x1a/0x40 [ 54.079329] ? __do_page_fault+0x358/0xb80 [ 54.083550] do_group_exit+0x111/0x330 [ 54.087424] SyS_exit_group+0x1d/0x20 [ 54.091206] ? do_group_exit+0x330/0x330 [ 54.095247] do_syscall_64+0x1e8/0x640 [ 54.099111] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 54.103938] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 54.109118] RIP: 0033:0x440b38 [ 54.112289] RSP: 002b:00007ffe9772d928 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 54.119974] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b38 [ 54.127235] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 54.134482] RBP: 00000000004c6fd0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 54.141728] R10: 0000000020000804 R11: 0000000000000246 R12: 0000000000000001 [ 54.148976] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 54.156684] [ 54.158296] Allocated by task 6829: [ 54.161911] save_stack_trace+0x16/0x20 [ 54.165869] save_stack+0x45/0xd0 [ 54.169301] kasan_kmalloc+0xce/0xf0 [ 54.172993] kasan_slab_alloc+0xf/0x20 [ 54.176856] kmem_cache_alloc_node+0x144/0x780 [ 54.181417] __alloc_skb+0x9c/0x500 [ 54.185019] sk_stream_alloc_skb+0xb3/0x780 [ 54.189313] tcp_sendmsg_locked+0xf61/0x3200 [ 54.193698] tcp_sendmsg+0x30/0x50 [ 54.197214] inet_sendmsg+0x122/0x500 [ 54.200992] sock_sendmsg+0xce/0x110 [ 54.204680] SYSC_sendto+0x206/0x310 [ 54.208368] SyS_sendto+0x40/0x50 [ 54.211798] do_syscall_64+0x1e8/0x640 [ 54.215663] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 54.220824] [ 54.222441] Freed by task 6829: [ 54.225697] save_stack_trace+0x16/0x20 [ 54.229797] save_stack+0x45/0xd0 [ 54.233241] kasan_slab_free+0x75/0xc0 [ 54.237154] kmem_cache_free+0x83/0x2b0 [ 54.241108] kfree_skbmem+0x8d/0x120 [ 54.244849] __kfree_skb+0x1e/0x30 [ 54.248366] tcp_remove_empty_skb.part.0+0x231/0x2e0 [ 54.253445] tcp_sendmsg_locked+0x1ced/0x3200 [ 54.257929] tcp_sendmsg+0x30/0x50 [ 54.261446] inet_sendmsg+0x122/0x500 [ 54.265223] sock_sendmsg+0xce/0x110 [ 54.268910] SYSC_sendto+0x206/0x310 [ 54.272608] SyS_sendto+0x40/0x50 [ 54.276046] do_syscall_64+0x1e8/0x640 [ 54.279908] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 54.285068] [ 54.286675] The buggy address belongs to the object at ffff888099bcda40 [ 54.286675] which belongs to the cache skbuff_fclone_cache of size 472 [ 54.299999] The buggy address is located 48 bytes inside of [ 54.299999] 472-byte region [ffff888099bcda40, ffff888099bcdc18) [ 54.311876] The buggy address belongs to the page: [ 54.316852] page:ffffea000266f340 count:1 mapcount:0 mapping:ffff888099bcd040 index:0x0 [ 54.324978] flags: 0x1fffc0000000100(slab) [ 54.329189] raw: 01fffc0000000100 ffff888099bcd040 0000000000000000 0000000100000006 [ 54.337095] raw: ffffea0002a03760 ffffea000285c860 ffff88821b75f3c0 0000000000000000 [ 54.344973] page dumped because: kasan: bad access detected [ 54.350664] [ 54.352270] Memory state around the buggy address: [ 54.357178] ffff888099bcd900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 54.364525] ffff888099bcd980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 54.371861] >ffff888099bcda00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 54.379196] ^ [ 54.386184] ffff888099bcda80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.393520] ffff888099bcdb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.400865] ================================================================== [ 54.408209] Disabling lock debugging due to kernel taint [ 54.414772] Kernel panic - not syncing: panic_on_warn set ... [ 54.414772] [ 54.422148] CPU: 0 PID: 6829 Comm: syz-executor106 Tainted: G B 4.14.145 #0 [ 54.430351] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 54.439691] Call Trace: [ 54.442258] dump_stack+0x138/0x197 [ 54.445874] ? tcp_init_tso_segs+0x1ae/0x200 [ 54.450519] panic+0x1f2/0x426 [ 54.453698] ? add_taint.cold+0x16/0x16 [ 54.457665] ? ___preempt_schedule+0x16/0x18 [ 54.462052] kasan_end_report+0x47/0x4f [ 54.466011] kasan_report.cold+0x130/0x2af [ 54.470220] __asan_report_load2_noabort+0x14/0x20 [ 54.475134] tcp_init_tso_segs+0x1ae/0x200 [ 54.479343] ? tcp_tso_segs+0x7d/0x1c0 [ 54.483209] tcp_write_xmit+0x15e/0x4960 [ 54.487261] ? tcp_v4_md5_lookup+0x23/0x30 [ 54.491471] ? tcp_established_options+0x2c5/0x420 [ 54.496374] ? tcp_current_mss+0x1dc/0x2f0 [ 54.500583] ? __alloc_skb+0x3ee/0x500 [ 54.504446] __tcp_push_pending_frames+0xa6/0x260 [ 54.509264] tcp_send_fin+0x17e/0xc40 [ 54.513039] tcp_close+0xcc8/0xfb0 [ 54.516641] ? __sock_release+0x89/0x2b0 [ 54.520693] ? ip_mc_drop_socket+0x1d6/0x230 [ 54.525078] inet_release+0xec/0x1c0 [ 54.528764] __sock_release+0xce/0x2b0 [ 54.532627] ? __sock_release+0x2b0/0x2b0 [ 54.536777] sock_close+0x1b/0x30 [ 54.540217] __fput+0x275/0x7a0 [ 54.543471] ____fput+0x16/0x20 [ 54.546814] task_work_run+0x114/0x190 [ 54.550706] do_exit+0x7df/0x2c10 [ 54.554154] ? mm_update_next_owner+0x5d0/0x5d0 [ 54.558804] ? up_read+0x1a/0x40 [ 54.562164] ? __do_page_fault+0x358/0xb80 [ 54.566379] do_group_exit+0x111/0x330 [ 54.570249] SyS_exit_group+0x1d/0x20 [ 54.574113] ? do_group_exit+0x330/0x330 [ 54.578167] do_syscall_64+0x1e8/0x640 [ 54.582029] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 54.586851] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 54.592014] RIP: 0033:0x440b38 [ 54.595190] RSP: 002b:00007ffe9772d928 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 54.602877] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b38 [ 54.610123] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 54.617379] RBP: 00000000004c6fd0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 54.624622] R10: 0000000020000804 R11: 0000000000000246 R12: 0000000000000001 [ 54.631868] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 54.640495] Kernel Offset: disabled [ 54.644115] Rebooting in 86400 seconds..