[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 32.942745] random: sshd: uninitialized urandom read (32 bytes read) [ 33.310419] kauditd_printk_skb: 10 callbacks suppressed [ 33.310427] audit: type=1400 audit(1569013622.695:35): avc: denied { map } for pid=6864 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 [ 33.366415] random: sshd: uninitialized urandom read (32 bytes read) [ 33.898264] random: sshd: uninitialized urandom read (32 bytes read) [ 41.488760] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.172' (ECDSA) to the list of known hosts. [ 46.982384] random: sshd: uninitialized urandom read (32 bytes read) [ 47.100964] audit: type=1400 audit(1569013636.485:36): avc: denied { map } for pid=6877 comm="syz-executor443" path="/root/syz-executor443634354" 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 [ 47.370921] IPVS: ftp: loaded support on port[0] = 21 [ 48.203987] chnl_net:caif_netlink_parms(): no params data found [ 48.231502] bridge0: port 1(bridge_slave_0) entered blocking state [ 48.238054] bridge0: port 1(bridge_slave_0) entered disabled state [ 48.245105] device bridge_slave_0 entered promiscuous mode [ 48.251978] bridge0: port 2(bridge_slave_1) entered blocking state [ 48.258340] bridge0: port 2(bridge_slave_1) entered disabled state [ 48.265290] device bridge_slave_1 entered promiscuous mode [ 48.278656] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 48.287632] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 48.303781] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 48.311507] team0: Port device team_slave_0 added [ 48.316833] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 48.323968] team0: Port device team_slave_1 added [ 48.329073] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready [ 48.336321] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready [ 48.401790] device hsr_slave_0 entered promiscuous mode [ 48.470370] device hsr_slave_1 entered promiscuous mode [ 48.510689] IPv6: ADDRCONF(NETDEV_UP): hsr_slave_0: link is not ready [ 48.517562] IPv6: ADDRCONF(NETDEV_UP): hsr_slave_1: link is not ready [ 48.529851] bridge0: port 2(bridge_slave_1) entered blocking state [ 48.536336] bridge0: port 2(bridge_slave_1) entered forwarding state [ 48.543218] bridge0: port 1(bridge_slave_0) entered blocking state [ 48.549558] bridge0: port 1(bridge_slave_0) entered forwarding state [ 48.576310] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 48.583089] 8021q: adding VLAN 0 to HW filter on device bond0 [ 48.591117] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 48.598987] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 48.617886] bridge0: port 1(bridge_slave_0) entered disabled state [ 48.625179] bridge0: port 2(bridge_slave_1) entered disabled state [ 48.634906] IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready [ 48.641080] 8021q: adding VLAN 0 to HW filter on device team0 [ 48.648848] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready [ 48.656987] bridge0: port 1(bridge_slave_0) entered blocking state [ 48.663350] bridge0: port 1(bridge_slave_0) entered forwarding state [ 48.681174] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready [ 48.688916] bridge0: port 2(bridge_slave_1) entered blocking state [ 48.695300] bridge0: port 2(bridge_slave_1) entered forwarding state [ 48.703265] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 48.710808] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 48.718194] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready executing program [ 48.726261] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready [ 48.734697] IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready [ 48.740882] IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready [ 48.747961] IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready [ 48.759365] IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready [ 48.768562] 8021q: adding VLAN 0 to HW filter on device batadv0 [ 48.941039] ================================================================== [ 48.948579] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x1ae/0x200 [ 48.955328] Read of size 2 at addr ffff88809506b530 by task syz-executor443/6878 [ 48.962841] [ 48.964452] CPU: 0 PID: 6878 Comm: syz-executor443 Not tainted 4.14.145 #0 [ 48.971460] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.980804] Call Trace: [ 48.983385] dump_stack+0x138/0x197 [ 48.986997] ? tcp_init_tso_segs+0x1ae/0x200 [ 48.991413] print_address_description.cold+0x7c/0x1dc [ 48.996682] ? tcp_init_tso_segs+0x1ae/0x200 [ 49.001084] kasan_report.cold+0xa9/0x2af [ 49.005213] __asan_report_load2_noabort+0x14/0x20 [ 49.010124] tcp_init_tso_segs+0x1ae/0x200 [ 49.014352] ? tcp_tso_segs+0x7d/0x1c0 [ 49.018219] tcp_write_xmit+0x15e/0x4960 [ 49.022260] ? tcp_v4_md5_lookup+0x23/0x30 [ 49.026476] ? tcp_established_options+0x2c5/0x420 [ 49.031389] ? tcp_current_mss+0x1dc/0x2f0 [ 49.035608] ? __alloc_skb+0x3ee/0x500 [ 49.039478] __tcp_push_pending_frames+0xa6/0x260 [ 49.044300] tcp_send_fin+0x17e/0xc40 [ 49.048080] tcp_close+0xcc8/0xfb0 [ 49.051600] ? __sock_release+0x89/0x2b0 [ 49.055638] ? ip_mc_drop_socket+0x1d6/0x230 [ 49.060045] inet_release+0xec/0x1c0 [ 49.063742] __sock_release+0xce/0x2b0 [ 49.067605] ? __sock_release+0x2b0/0x2b0 [ 49.071734] sock_close+0x1b/0x30 [ 49.075168] __fput+0x275/0x7a0 [ 49.078432] ____fput+0x16/0x20 [ 49.081702] task_work_run+0x114/0x190 [ 49.085583] do_exit+0x7df/0x2c10 [ 49.089019] ? mm_update_next_owner+0x5d0/0x5d0 [ 49.093668] ? up_read+0x1a/0x40 [ 49.097017] ? __do_page_fault+0x358/0xb80 [ 49.101233] do_group_exit+0x111/0x330 [ 49.105101] SyS_exit_group+0x1d/0x20 [ 49.108896] ? do_group_exit+0x330/0x330 [ 49.112948] do_syscall_64+0x1e8/0x640 [ 49.116825] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 49.121670] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.126853] RIP: 0033:0x440b58 [ 49.130023] RSP: 002b:00007fff17e72698 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 49.137719] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b58 [ 49.144972] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 49.152222] RBP: 00000000004c6ff0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 49.159475] R10: 0000000020000800 R11: 0000000000000246 R12: 0000000000000001 [ 49.166723] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 49.173977] [ 49.175584] Allocated by task 6878: [ 49.179192] save_stack_trace+0x16/0x20 [ 49.183145] save_stack+0x45/0xd0 [ 49.186575] kasan_kmalloc+0xce/0xf0 [ 49.190270] kasan_slab_alloc+0xf/0x20 [ 49.194148] kmem_cache_alloc_node+0x144/0x780 [ 49.198720] __alloc_skb+0x9c/0x500 [ 49.202325] sk_stream_alloc_skb+0xb3/0x780 [ 49.206622] tcp_sendmsg_locked+0xf61/0x3200 [ 49.211008] tcp_sendmsg+0x30/0x50 [ 49.214524] inet_sendmsg+0x122/0x500 [ 49.218303] sock_sendmsg+0xce/0x110 [ 49.221991] SYSC_sendto+0x206/0x310 [ 49.225693] SyS_sendto+0x40/0x50 [ 49.229122] do_syscall_64+0x1e8/0x640 [ 49.232992] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.238155] [ 49.239760] Freed by task 6878: [ 49.243022] save_stack_trace+0x16/0x20 [ 49.246973] save_stack+0x45/0xd0 [ 49.250425] kasan_slab_free+0x75/0xc0 [ 49.254368] kmem_cache_free+0x83/0x2b0 [ 49.258493] kfree_skbmem+0x8d/0x120 [ 49.262296] __kfree_skb+0x1e/0x30 [ 49.265846] tcp_remove_empty_skb.part.0+0x231/0x2e0 [ 49.270933] tcp_sendmsg_locked+0x1ced/0x3200 [ 49.275412] tcp_sendmsg+0x30/0x50 [ 49.278931] inet_sendmsg+0x122/0x500 [ 49.282708] sock_sendmsg+0xce/0x110 [ 49.286516] SYSC_sendto+0x206/0x310 [ 49.290225] SyS_sendto+0x40/0x50 [ 49.293679] do_syscall_64+0x1e8/0x640 [ 49.297553] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.302721] [ 49.304332] The buggy address belongs to the object at ffff88809506b500 [ 49.304332] which belongs to the cache skbuff_fclone_cache of size 472 [ 49.317664] The buggy address is located 48 bytes inside of [ 49.317664] 472-byte region [ffff88809506b500, ffff88809506b6d8) [ 49.329433] The buggy address belongs to the page: [ 49.334346] page:ffffea0002541ac0 count:1 mapcount:0 mapping:ffff88809506b000 index:0x0 [ 49.343164] flags: 0x1fffc0000000100(slab) [ 49.347381] raw: 01fffc0000000100 ffff88809506b000 0000000000000000 0000000100000006 [ 49.355274] raw: ffffea000258b8a0 ffffea0002a681e0 ffff8880a9e19a80 0000000000000000 [ 49.363155] page dumped because: kasan: bad access detected [ 49.368842] [ 49.370448] Memory state around the buggy address: [ 49.375391] ffff88809506b400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 49.382737] ffff88809506b480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 49.390080] >ffff88809506b500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.397424] ^ [ 49.402331] ffff88809506b580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.409721] ffff88809506b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.417061] ================================================================== [ 49.424399] Disabling lock debugging due to kernel taint [ 49.431637] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 49.433398] Kernel panic - not syncing: panic_on_warn set ... [ 49.433398] [ 49.445514] CPU: 1 PID: 6878 Comm: syz-executor443 Tainted: G B 4.14.145 #0 [ 49.453736] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 49.463087] Call Trace: [ 49.465669] dump_stack+0x138/0x197 [ 49.469277] ? tcp_init_tso_segs+0x1ae/0x200 [ 49.473662] panic+0x1f2/0x426 [ 49.476830] ? add_taint.cold+0x16/0x16 [ 49.480782] ? ___preempt_schedule+0x16/0x18 [ 49.485172] kasan_end_report+0x47/0x4f [ 49.489123] kasan_report.cold+0x130/0x2af [ 49.493352] __asan_report_load2_noabort+0x14/0x20 [ 49.498263] tcp_init_tso_segs+0x1ae/0x200 [ 49.502477] ? tcp_tso_segs+0x7d/0x1c0 [ 49.506355] tcp_write_xmit+0x15e/0x4960 [ 49.510509] ? tcp_v4_md5_lookup+0x23/0x30 [ 49.514741] ? tcp_established_options+0x2c5/0x420 [ 49.519733] ? tcp_current_mss+0x1dc/0x2f0 [ 49.523973] ? __alloc_skb+0x3ee/0x500 [ 49.527845] __tcp_push_pending_frames+0xa6/0x260 [ 49.532673] tcp_send_fin+0x17e/0xc40 [ 49.536620] tcp_close+0xcc8/0xfb0 [ 49.540208] ? __sock_release+0x89/0x2b0 [ 49.544271] ? ip_mc_drop_socket+0x1d6/0x230 [ 49.548663] inet_release+0xec/0x1c0 [ 49.552357] __sock_release+0xce/0x2b0 [ 49.556239] ? __sock_release+0x2b0/0x2b0 [ 49.560378] sock_close+0x1b/0x30 [ 49.563987] __fput+0x275/0x7a0 [ 49.567257] ____fput+0x16/0x20 [ 49.570522] task_work_run+0x114/0x190 [ 49.574587] do_exit+0x7df/0x2c10 [ 49.578026] ? mm_update_next_owner+0x5d0/0x5d0 [ 49.582681] ? up_read+0x1a/0x40 [ 49.586029] ? __do_page_fault+0x358/0xb80 [ 49.590244] do_group_exit+0x111/0x330 [ 49.594108] SyS_exit_group+0x1d/0x20 [ 49.597896] ? do_group_exit+0x330/0x330 [ 49.601934] do_syscall_64+0x1e8/0x640 [ 49.605802] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 49.610625] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.615795] RIP: 0033:0x440b58 [ 49.618975] RSP: 002b:00007fff17e72698 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 49.626661] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b58 [ 49.633910] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 49.641169] RBP: 00000000004c6ff0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 49.648428] R10: 0000000020000800 R11: 0000000000000246 R12: 0000000000000001 [ 49.655674] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 49.664347] Kernel Offset: disabled [ 49.667980] Rebooting in 86400 seconds..