[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 39.561656] random: sshd: uninitialized urandom read (32 bytes read) [ 39.735522] kauditd_printk_skb: 9 callbacks suppressed [ 39.735530] audit: type=1400 audit(1569043669.238:35): avc: denied { map } for pid=6845 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 [ 39.841858] random: sshd: uninitialized urandom read (32 bytes read) [ 40.388147] random: sshd: uninitialized urandom read (32 bytes read) [ 72.592021] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.33' (ECDSA) to the list of known hosts. [ 78.113160] random: sshd: uninitialized urandom read (32 bytes read) [ 78.227502] audit: type=1400 audit(1569043707.728:36): avc: denied { map } for pid=6857 comm="syz-executor314" path="/root/syz-executor314545984" dev="sda1" ino=1426 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 78.570802] IPVS: ftp: loaded support on port[0] = 21 [ 79.567484] chnl_net:caif_netlink_parms(): no params data found [ 79.595461] bridge0: port 1(bridge_slave_0) entered blocking state [ 79.602099] bridge0: port 1(bridge_slave_0) entered disabled state [ 79.608967] device bridge_slave_0 entered promiscuous mode [ 79.615961] bridge0: port 2(bridge_slave_1) entered blocking state [ 79.622387] bridge0: port 2(bridge_slave_1) entered disabled state [ 79.629127] device bridge_slave_1 entered promiscuous mode [ 79.643010] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 79.651616] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 79.666473] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 79.673729] team0: Port device team_slave_0 added [ 79.679010] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 79.686085] team0: Port device team_slave_1 added [ 79.691222] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready [ 79.698304] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready [ 79.752053] device hsr_slave_0 entered promiscuous mode [ 79.820247] device hsr_slave_1 entered promiscuous mode [ 79.860432] IPv6: ADDRCONF(NETDEV_UP): hsr_slave_0: link is not ready [ 79.867244] IPv6: ADDRCONF(NETDEV_UP): hsr_slave_1: link is not ready [ 79.879632] bridge0: port 2(bridge_slave_1) entered blocking state [ 79.886056] bridge0: port 2(bridge_slave_1) entered forwarding state [ 79.892887] bridge0: port 1(bridge_slave_0) entered blocking state [ 79.899230] bridge0: port 1(bridge_slave_0) entered forwarding state [ 79.923897] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 79.929971] 8021q: adding VLAN 0 to HW filter on device bond0 [ 79.938760] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 79.946713] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 79.964859] bridge0: port 1(bridge_slave_0) entered disabled state [ 79.972145] bridge0: port 2(bridge_slave_1) entered disabled state [ 79.981106] IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready [ 79.987178] 8021q: adding VLAN 0 to HW filter on device team0 [ 79.994984] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready [ 80.002524] bridge0: port 1(bridge_slave_0) entered blocking state [ 80.008839] bridge0: port 1(bridge_slave_0) entered forwarding state [ 80.017978] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready [ 80.025908] bridge0: port 2(bridge_slave_1) entered blocking state [ 80.032254] bridge0: port 2(bridge_slave_1) entered forwarding state [ 80.048960] hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network [ 80.058717] hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network [ 80.069251] IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready [ 80.076744] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 80.084320] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 80.092031] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready [ 80.099357] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready [ 80.107364] IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready [ 80.114095] IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready executing program [ 80.124720] IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready [ 80.134068] 8021q: adding VLAN 0 to HW filter on device batadv0 [ 80.240888] ================================================================== [ 80.248375] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x1ae/0x200 [ 80.255108] Read of size 2 at addr ffff888081814330 by task syz-executor314/6858 [ 80.262643] [ 80.264251] CPU: 0 PID: 6858 Comm: syz-executor314 Not tainted 4.14.145 #0 [ 80.271237] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 80.280568] Call Trace: [ 80.283134] dump_stack+0x138/0x197 [ 80.286742] ? tcp_init_tso_segs+0x1ae/0x200 [ 80.291129] print_address_description.cold+0x7c/0x1dc [ 80.296383] ? tcp_init_tso_segs+0x1ae/0x200 [ 80.300766] kasan_report.cold+0xa9/0x2af [ 80.304892] __asan_report_load2_noabort+0x14/0x20 [ 80.309796] tcp_init_tso_segs+0x1ae/0x200 [ 80.314007] ? tcp_tso_segs+0x7d/0x1c0 [ 80.317871] tcp_write_xmit+0x15e/0x4960 [ 80.321907] ? tcp_v4_md5_lookup+0x23/0x30 [ 80.326120] ? tcp_established_options+0x2c5/0x420 [ 80.331042] ? tcp_current_mss+0x1dc/0x2f0 [ 80.335259] ? __alloc_skb+0x3ee/0x500 [ 80.339126] __tcp_push_pending_frames+0xa6/0x260 [ 80.343946] tcp_send_fin+0x17e/0xc40 [ 80.347724] tcp_close+0xcc8/0xfb0 [ 80.351240] ? __sock_release+0x89/0x2b0 [ 80.355279] ? ip_mc_drop_socket+0x1d6/0x230 [ 80.359664] inet_release+0xec/0x1c0 [ 80.363375] __sock_release+0xce/0x2b0 [ 80.367254] ? __sock_release+0x2b0/0x2b0 [ 80.371377] sock_close+0x1b/0x30 [ 80.374824] __fput+0x275/0x7a0 [ 80.378083] ____fput+0x16/0x20 [ 80.381367] task_work_run+0x114/0x190 [ 80.385233] do_exit+0x7df/0x2c10 [ 80.388665] ? mm_update_next_owner+0x5d0/0x5d0 [ 80.393312] ? up_read+0x1a/0x40 [ 80.396655] ? __do_page_fault+0x358/0xb80 [ 80.400867] do_group_exit+0x111/0x330 [ 80.404746] SyS_exit_group+0x1d/0x20 [ 80.408523] ? do_group_exit+0x330/0x330 [ 80.412564] do_syscall_64+0x1e8/0x640 [ 80.416427] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 80.421266] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 80.426447] RIP: 0033:0x440618 [ 80.429613] RSP: 002b:00007ffca8db1a88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 80.437299] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440618 [ 80.444543] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 80.451790] RBP: 00000000004c6970 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 80.459043] R10: 0000000020000800 R11: 0000000000000246 R12: 0000000000000001 [ 80.466323] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 80.473577] [ 80.475183] Allocated by task 6858: [ 80.478786] save_stack_trace+0x16/0x20 [ 80.482750] save_stack+0x45/0xd0 [ 80.486178] kasan_kmalloc+0xce/0xf0 [ 80.489991] kasan_slab_alloc+0xf/0x20 [ 80.493912] kmem_cache_alloc_node+0x144/0x780 [ 80.498474] __alloc_skb+0x9c/0x500 [ 80.502123] sk_stream_alloc_skb+0xb3/0x780 [ 80.506424] tcp_sendmsg_locked+0xf61/0x3200 [ 80.510810] tcp_sendmsg+0x30/0x50 [ 80.514330] inet_sendmsg+0x122/0x500 [ 80.518113] sock_sendmsg+0xce/0x110 [ 80.521803] SYSC_sendto+0x206/0x310 [ 80.525498] SyS_sendto+0x40/0x50 [ 80.528960] do_syscall_64+0x1e8/0x640 [ 80.532852] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 80.538020] [ 80.539626] Freed by task 6858: [ 80.542888] save_stack_trace+0x16/0x20 [ 80.546841] save_stack+0x45/0xd0 [ 80.550272] kasan_slab_free+0x75/0xc0 [ 80.554138] kmem_cache_free+0x83/0x2b0 [ 80.558087] kfree_skbmem+0x8d/0x120 [ 80.561862] __kfree_skb+0x1e/0x30 [ 80.565376] tcp_remove_empty_skb.part.0+0x231/0x2e0 [ 80.570468] tcp_sendmsg_locked+0x1ced/0x3200 [ 80.574937] tcp_sendmsg+0x30/0x50 [ 80.578470] inet_sendmsg+0x122/0x500 [ 80.582246] sock_sendmsg+0xce/0x110 [ 80.585934] SYSC_sendto+0x206/0x310 [ 80.589622] SyS_sendto+0x40/0x50 [ 80.593050] do_syscall_64+0x1e8/0x640 [ 80.596913] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 80.602087] [ 80.603707] The buggy address belongs to the object at ffff888081814300 [ 80.603707] which belongs to the cache skbuff_fclone_cache of size 472 [ 80.617033] The buggy address is located 48 bytes inside of [ 80.617033] 472-byte region [ffff888081814300, ffff8880818144d8) [ 80.628795] The buggy address belongs to the page: [ 80.633721] page:ffffea0002060500 count:1 mapcount:0 mapping:ffff888081814080 index:0x0 [ 80.641843] flags: 0x1fffc0000000100(slab) [ 80.646054] raw: 01fffc0000000100 ffff888081814080 0000000000000000 0000000100000006 [ 80.653909] raw: ffffea000264e960 ffffea00020162e0 ffff8880a9e19a80 0000000000000000 [ 80.661762] page dumped because: kasan: bad access detected [ 80.667444] [ 80.669047] Memory state around the buggy address: [ 80.673951] ffff888081814200: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc [ 80.681286] ffff888081814280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 80.688623] >ffff888081814300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 80.695957] ^ [ 80.700860] ffff888081814380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 80.708193] ffff888081814400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 80.715539] ================================================================== [ 80.722873] Disabling lock debugging due to kernel taint [ 80.730823] Kernel panic - not syncing: panic_on_warn set ... [ 80.730823] [ 80.738204] CPU: 0 PID: 6858 Comm: syz-executor314 Tainted: G B 4.14.145 #0 [ 80.746406] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 80.755734] Call Trace: [ 80.758307] dump_stack+0x138/0x197 [ 80.761917] ? tcp_init_tso_segs+0x1ae/0x200 [ 80.766310] panic+0x1f2/0x426 [ 80.769579] ? add_taint.cold+0x16/0x16 [ 80.773584] ? ___preempt_schedule+0x16/0x18 [ 80.777971] kasan_end_report+0x47/0x4f [ 80.781963] kasan_report.cold+0x130/0x2af [ 80.786176] __asan_report_load2_noabort+0x14/0x20 [ 80.791082] tcp_init_tso_segs+0x1ae/0x200 [ 80.795290] ? tcp_tso_segs+0x7d/0x1c0 [ 80.799156] tcp_write_xmit+0x15e/0x4960 [ 80.803191] ? tcp_v4_md5_lookup+0x23/0x30 [ 80.807406] ? tcp_established_options+0x2c5/0x420 [ 80.812311] ? tcp_current_mss+0x1dc/0x2f0 [ 80.816524] ? __alloc_skb+0x3ee/0x500 [ 80.820412] __tcp_push_pending_frames+0xa6/0x260 [ 80.825232] tcp_send_fin+0x17e/0xc40 [ 80.829010] tcp_close+0xcc8/0xfb0 [ 80.832524] ? __sock_release+0x89/0x2b0 [ 80.836564] ? ip_mc_drop_socket+0x1d6/0x230 [ 80.840949] inet_release+0xec/0x1c0 [ 80.844641] __sock_release+0xce/0x2b0 [ 80.848513] ? __sock_release+0x2b0/0x2b0 [ 80.852634] sock_close+0x1b/0x30 [ 80.856065] __fput+0x275/0x7a0 [ 80.859320] ____fput+0x16/0x20 [ 80.862575] task_work_run+0x114/0x190 [ 80.866441] do_exit+0x7df/0x2c10 [ 80.869877] ? mm_update_next_owner+0x5d0/0x5d0 [ 80.874526] ? up_read+0x1a/0x40 [ 80.877873] ? __do_page_fault+0x358/0xb80 [ 80.882096] do_group_exit+0x111/0x330 [ 80.885961] SyS_exit_group+0x1d/0x20 [ 80.889734] ? do_group_exit+0x330/0x330 [ 80.893769] do_syscall_64+0x1e8/0x640 [ 80.897632] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 80.902454] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 80.907629] RIP: 0033:0x440618 [ 80.910796] RSP: 002b:00007ffca8db1a88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 80.918483] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440618 [ 80.925729] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 80.932993] RBP: 00000000004c6970 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 80.940249] R10: 0000000020000800 R11: 0000000000000246 R12: 0000000000000001 [ 80.947602] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 80.956259] Kernel Offset: disabled [ 80.959924] Rebooting in 86400 seconds..