[....] Starting OpenBSD Secure Shell server: sshd[ 11.733570] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 42.401679] random: sshd: uninitialized urandom read (32 bytes read) [ 42.721711] audit: type=1400 audit(1569059866.025:6): avc: denied { map } for pid=1772 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 [ 42.765006] random: sshd: uninitialized urandom read (32 bytes read) [ 43.286785] random: sshd: uninitialized urandom read (32 bytes read) [ 43.441475] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.25' (ECDSA) to the list of known hosts. [ 48.887600] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 48.983096] audit: type=1400 audit(1569059872.285:7): avc: denied { map } for pid=1784 comm="syz-executor697" path="/root/syz-executor697041981" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 49.013616] ================================================================== [ 49.021054] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x19d/0x1f0 [ 49.028251] Read of size 2 at addr ffff8881d0629930 by task syz-executor697/1784 [ 49.035783] [ 49.037398] CPU: 0 PID: 1784 Comm: syz-executor697 Not tainted 4.14.145+ #0 [ 49.044775] Call Trace: [ 49.047415] dump_stack+0xca/0x134 [ 49.050967] ? tcp_init_tso_segs+0x19d/0x1f0 [ 49.055364] ? tcp_init_tso_segs+0x19d/0x1f0 [ 49.059779] print_address_description+0x60/0x226 [ 49.064668] ? tcp_init_tso_segs+0x19d/0x1f0 [ 49.069088] ? tcp_init_tso_segs+0x19d/0x1f0 [ 49.073491] __kasan_report.cold+0x1a/0x41 [ 49.077983] ? kvm_guest_cpu_init+0x220/0x220 [ 49.082468] ? tcp_init_tso_segs+0x19d/0x1f0 [ 49.086861] tcp_init_tso_segs+0x19d/0x1f0 [ 49.091073] ? tcp_tso_segs+0x7b/0x1c0 [ 49.095379] tcp_write_xmit+0x15a/0x4730 [ 49.099421] ? ip6_mtu+0x206/0x330 [ 49.102943] ? lock_downgrade+0x5d0/0x5d0 [ 49.107159] ? lock_acquire+0x12b/0x360 [ 49.111313] __tcp_push_pending_frames+0xa0/0x230 [ 49.117467] tcp_send_fin+0x154/0xbc0 [ 49.121265] tcp_close+0xc62/0xf40 [ 49.124807] ? lock_acquire+0x12b/0x360 [ 49.128761] ? __sock_release+0x86/0x2c0 [ 49.132817] inet_release+0xe9/0x1c0 [ 49.136555] inet6_release+0x4c/0x70 [ 49.140259] __sock_release+0xd2/0x2c0 [ 49.144176] ? __sock_release+0x2c0/0x2c0 [ 49.148387] sock_close+0x15/0x20 [ 49.152256] __fput+0x25e/0x710 [ 49.155596] task_work_run+0x125/0x1a0 [ 49.159468] do_exit+0x9cb/0x2a20 [ 49.162908] ? mm_update_next_owner+0x610/0x610 [ 49.167570] ? SyS_socket+0x143/0x1e0 [ 49.171365] do_group_exit+0x100/0x2e0 [ 49.175232] SyS_exit_group+0x19/0x20 [ 49.179010] ? do_group_exit+0x2e0/0x2e0 [ 49.183052] do_syscall_64+0x19b/0x520 [ 49.186939] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.192430] RIP: 0033:0x43ee88 [ 49.195600] RSP: 002b:00007ffd0b01f168 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 49.203317] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee88 [ 49.210826] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 49.218076] RBP: 00000000004be688 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 49.225327] R10: 0000000020000004 R11: 0000000000000246 R12: 0000000000000001 [ 49.232599] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 [ 49.240207] [ 49.241815] Allocated by task 1784: [ 49.245523] __kasan_kmalloc.part.0+0x53/0xc0 [ 49.249995] kmem_cache_alloc+0xee/0x360 [ 49.254049] __alloc_skb+0xea/0x5c0 [ 49.257654] sk_stream_alloc_skb+0xf4/0x8a0 [ 49.261959] tcp_sendmsg_locked+0xf11/0x2f50 [ 49.266353] tcp_sendmsg+0x2b/0x40 [ 49.269870] inet_sendmsg+0x15b/0x520 [ 49.273746] sock_sendmsg+0xb7/0x100 [ 49.277524] SyS_sendto+0x1de/0x2f0 [ 49.281144] do_syscall_64+0x19b/0x520 [ 49.285008] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.291214] 0xffffffffffffffff [ 49.294468] [ 49.296073] Freed by task 1784: [ 49.299331] __kasan_slab_free+0x164/0x210 [ 49.303570] kmem_cache_free+0xd7/0x3b0 [ 49.310648] kfree_skbmem+0x84/0x110 [ 49.314340] tcp_remove_empty_skb+0x264/0x320 [ 49.318811] tcp_sendmsg_locked+0x1c09/0x2f50 [ 49.323297] tcp_sendmsg+0x2b/0x40 [ 49.326829] inet_sendmsg+0x15b/0x520 [ 49.330608] sock_sendmsg+0xb7/0x100 [ 49.334298] SyS_sendto+0x1de/0x2f0 [ 49.337903] do_syscall_64+0x19b/0x520 [ 49.341772] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.347209] 0xffffffffffffffff [ 49.350480] [ 49.352111] The buggy address belongs to the object at ffff8881d0629900 [ 49.352111] which belongs to the cache skbuff_fclone_cache of size 456 [ 49.365468] The buggy address is located 48 bytes inside of [ 49.365468] 456-byte region [ffff8881d0629900, ffff8881d0629ac8) [ 49.378135] The buggy address belongs to the page: [ 49.383139] page:ffffea0007418a00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 49.394766] flags: 0x4000000000010200(slab|head) [ 49.399514] raw: 4000000000010200 0000000000000000 0000000000000000 00000001800c000c [ 49.407394] raw: dead000000000100 dead000000000200 ffff8881dab70400 0000000000000000 [ 49.415354] page dumped because: kasan: bad access detected [ 49.421047] [ 49.422661] Memory state around the buggy address: [ 49.427580] ffff8881d0629800: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc [ 49.434928] ffff8881d0629880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 49.442453] >ffff8881d0629900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.449788] ^ [ 49.454780] ffff8881d0629980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.462204] ffff8881d0629a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.469646] ================================================================== [ 49.477096] Disabling lock debugging due to kernel taint [ 49.483024] Kernel panic - not syncing: panic_on_warn set ... [ 49.483024] [ 49.490387] CPU: 0 PID: 1784 Comm: syz-executor697 Tainted: G B 4.14.145+ #0 [ 49.499655] Call Trace: [ 49.502227] dump_stack+0xca/0x134 [ 49.505951] panic+0x1ea/0x3d3 [ 49.509304] ? add_taint.cold+0x16/0x16 [ 49.513258] ? tcp_init_tso_segs+0x19d/0x1f0 [ 49.517743] ? ___preempt_schedule+0x16/0x18 [ 49.522139] ? tcp_init_tso_segs+0x19d/0x1f0 [ 49.526546] end_report+0x43/0x49 [ 49.529991] ? tcp_init_tso_segs+0x19d/0x1f0 [ 49.535554] __kasan_report.cold+0xd/0x41 [ 49.539801] ? kvm_guest_cpu_init+0x220/0x220 [ 49.544640] ? tcp_init_tso_segs+0x19d/0x1f0 [ 49.549912] tcp_init_tso_segs+0x19d/0x1f0 [ 49.554126] ? tcp_tso_segs+0x7b/0x1c0 [ 49.558426] tcp_write_xmit+0x15a/0x4730 [ 49.562467] ? ip6_mtu+0x206/0x330 [ 49.568247] ? lock_downgrade+0x5d0/0x5d0 [ 49.572368] ? lock_acquire+0x12b/0x360 [ 49.576342] __tcp_push_pending_frames+0xa0/0x230 [ 49.581182] tcp_send_fin+0x154/0xbc0 [ 49.584960] tcp_close+0xc62/0xf40 [ 49.588489] ? lock_acquire+0x12b/0x360 [ 49.592570] ? __sock_release+0x86/0x2c0 [ 49.596616] inet_release+0xe9/0x1c0 [ 49.600313] inet6_release+0x4c/0x70 [ 49.604006] __sock_release+0xd2/0x2c0 [ 49.607872] ? __sock_release+0x2c0/0x2c0 [ 49.612085] sock_close+0x15/0x20 [ 49.615533] __fput+0x25e/0x710 [ 49.618802] task_work_run+0x125/0x1a0 [ 49.622689] do_exit+0x9cb/0x2a20 [ 49.626141] ? mm_update_next_owner+0x610/0x610 [ 49.630792] ? SyS_socket+0x143/0x1e0 [ 49.634585] do_group_exit+0x100/0x2e0 [ 49.638448] SyS_exit_group+0x19/0x20 [ 49.643106] ? do_group_exit+0x2e0/0x2e0 [ 49.647144] do_syscall_64+0x19b/0x520 [ 49.651012] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.656192] RIP: 0033:0x43ee88 [ 49.659360] RSP: 002b:00007ffd0b01f168 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 49.667048] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee88 [ 49.674294] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 49.681552] RBP: 00000000004be688 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 49.689060] R10: 0000000020000004 R11: 0000000000000246 R12: 0000000000000001 [ 49.696317] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 [ 49.704444] Kernel Offset: 0x2000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 49.715347] Rebooting in 86400 seconds..