[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.252850] random: sshd: uninitialized urandom read (32 bytes read) [ 25.635637] audit: type=1400 audit(1569081272.049:6): avc: denied { map } for pid=1767 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 [ 25.665492] random: sshd: uninitialized urandom read (32 bytes read) [ 26.163556] random: sshd: uninitialized urandom read (32 bytes read) [ 26.306425] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.21' (ECDSA) to the list of known hosts. [ 31.745152] random: sshd: uninitialized urandom read (32 bytes read) [ 31.839494] audit: type=1400 audit(1569081278.249:7): avc: denied { map } for pid=1785 comm="syz-executor085" path="/root/syz-executor085373823" 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 executing program [ 32.630704] ================================================================== [ 32.638122] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x19d/0x1f0 [ 32.644850] Read of size 2 at addr ffff8881c0eef930 by task syz-executor085/1786 [ 32.652356] [ 32.653963] CPU: 0 PID: 1786 Comm: syz-executor085 Not tainted 4.14.145+ #0 [ 32.661036] Call Trace: [ 32.663601] dump_stack+0xca/0x134 [ 32.667118] ? tcp_init_tso_segs+0x19d/0x1f0 [ 32.671501] ? tcp_init_tso_segs+0x19d/0x1f0 [ 32.675885] print_address_description+0x60/0x226 [ 32.680701] ? tcp_init_tso_segs+0x19d/0x1f0 [ 32.685107] ? tcp_init_tso_segs+0x19d/0x1f0 [ 32.689504] __kasan_report.cold+0x1a/0x41 [ 32.693723] ? kvm_guest_cpu_init+0x220/0x220 [ 32.698192] ? tcp_init_tso_segs+0x19d/0x1f0 [ 32.702576] tcp_init_tso_segs+0x19d/0x1f0 [ 32.706785] ? tcp_tso_segs+0x7b/0x1c0 [ 32.710649] tcp_write_xmit+0x15a/0x4730 [ 32.714692] ? memset+0x20/0x40 [ 32.717956] __tcp_push_pending_frames+0xa0/0x230 [ 32.722775] tcp_send_fin+0x154/0xbc0 [ 32.726556] tcp_close+0xc62/0xf40 [ 32.730080] inet_release+0xe9/0x1c0 [ 32.733805] __sock_release+0xd2/0x2c0 [ 32.737700] ? __sock_release+0x2c0/0x2c0 [ 32.741822] sock_close+0x15/0x20 [ 32.745254] __fput+0x25e/0x710 [ 32.748516] task_work_run+0x125/0x1a0 [ 32.752387] do_exit+0x9cb/0x2a20 [ 32.755821] ? mm_update_next_owner+0x610/0x610 [ 32.760478] do_group_exit+0x100/0x2e0 [ 32.764344] SyS_exit_group+0x19/0x20 [ 32.768118] ? do_group_exit+0x2e0/0x2e0 [ 32.772203] do_syscall_64+0x19b/0x520 [ 32.776074] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 32.781269] RIP: 0033:0x440b38 [ 32.784443] RSP: 002b:00007fffdd3eb888 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 32.792126] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b38 [ 32.799371] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 32.806617] RBP: 00000000004c6fd0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 32.813861] R10: 0000000020000002 R11: 0000000000000246 R12: 0000000000000001 [ 32.821119] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 32.828378] [ 32.829981] Allocated by task 1786: [ 32.833584] __kasan_kmalloc.part.0+0x53/0xc0 [ 32.838053] kmem_cache_alloc+0xee/0x360 [ 32.842090] __alloc_skb+0xea/0x5c0 [ 32.845703] sk_stream_alloc_skb+0xf4/0x8a0 [ 32.850001] tcp_sendmsg_locked+0xf11/0x2f50 [ 32.854937] tcp_sendmsg+0x2b/0x40 [ 32.858462] inet_sendmsg+0x15b/0x520 [ 32.862241] sock_sendmsg+0xb7/0x100 [ 32.865930] SyS_sendto+0x1de/0x2f0 [ 32.869531] do_syscall_64+0x19b/0x520 [ 32.873395] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 32.878558] 0xffffffffffffffff [ 32.881808] [ 32.883410] Freed by task 1786: [ 32.886667] __kasan_slab_free+0x164/0x210 [ 32.890889] kmem_cache_free+0xd7/0x3b0 [ 32.894837] kfree_skbmem+0x84/0x110 [ 32.898524] tcp_remove_empty_skb+0x264/0x320 [ 32.902992] tcp_sendmsg_locked+0x1c09/0x2f50 [ 32.907461] tcp_sendmsg+0x2b/0x40 [ 32.910973] inet_sendmsg+0x15b/0x520 [ 32.914748] sock_sendmsg+0xb7/0x100 [ 32.918436] SyS_sendto+0x1de/0x2f0 [ 32.922038] do_syscall_64+0x19b/0x520 [ 32.925904] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 32.931066] 0xffffffffffffffff [ 32.934319] [ 32.935924] The buggy address belongs to the object at ffff8881c0eef900 [ 32.935924] which belongs to the cache skbuff_fclone_cache of size 456 [ 32.949247] The buggy address is located 48 bytes inside of [ 32.949247] 456-byte region [ffff8881c0eef900, ffff8881c0eefac8) [ 32.961004] The buggy address belongs to the page: [ 32.965910] page:ffffea000703bb80 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 32.975852] flags: 0x4000000000010200(slab|head) [ 32.980589] raw: 4000000000010200 0000000000000000 0000000000000000 00000001800c000c [ 32.988445] raw: dead000000000100 dead000000000200 ffff8881d6770400 0000000000000000 [ 32.996296] page dumped because: kasan: bad access detected [ 33.001976] [ 33.003583] Memory state around the buggy address: [ 33.008517] ffff8881c0eef800: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc [ 33.015881] ffff8881c0eef880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 33.023248] >ffff8881c0eef900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.030582] ^ [ 33.035484] ffff8881c0eef980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.042817] ffff8881c0eefa00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.050146] ================================================================== [ 33.057475] Disabling lock debugging due to kernel taint [ 33.063207] Kernel panic - not syncing: panic_on_warn set ... [ 33.063207] [ 33.070564] CPU: 0 PID: 1786 Comm: syz-executor085 Tainted: G B 4.14.145+ #0 [ 33.078852] Call Trace: [ 33.081418] dump_stack+0xca/0x134 [ 33.084933] panic+0x1ea/0x3d3 [ 33.088097] ? add_taint.cold+0x16/0x16 [ 33.092065] ? tcp_init_tso_segs+0x19d/0x1f0 [ 33.096448] ? ___preempt_schedule+0x16/0x18 [ 33.100831] ? tcp_init_tso_segs+0x19d/0x1f0 [ 33.105229] end_report+0x43/0x49 [ 33.108655] ? tcp_init_tso_segs+0x19d/0x1f0 [ 33.113034] __kasan_report.cold+0xd/0x41 [ 33.117154] ? kvm_guest_cpu_init+0x220/0x220 [ 33.121621] ? tcp_init_tso_segs+0x19d/0x1f0 [ 33.126012] tcp_init_tso_segs+0x19d/0x1f0 [ 33.130219] ? tcp_tso_segs+0x7b/0x1c0 [ 33.134081] tcp_write_xmit+0x15a/0x4730 [ 33.138118] ? memset+0x20/0x40 [ 33.141376] __tcp_push_pending_frames+0xa0/0x230 [ 33.146193] tcp_send_fin+0x154/0xbc0 [ 33.149972] tcp_close+0xc62/0xf40 [ 33.153505] inet_release+0xe9/0x1c0 [ 33.157191] __sock_release+0xd2/0x2c0 [ 33.161052] ? __sock_release+0x2c0/0x2c0 [ 33.165170] sock_close+0x15/0x20 [ 33.168597] __fput+0x25e/0x710 [ 33.171862] task_work_run+0x125/0x1a0 [ 33.175724] do_exit+0x9cb/0x2a20 [ 33.179154] ? mm_update_next_owner+0x610/0x610 [ 33.183802] do_group_exit+0x100/0x2e0 [ 33.187665] SyS_exit_group+0x19/0x20 [ 33.191439] ? do_group_exit+0x2e0/0x2e0 [ 33.195469] do_syscall_64+0x19b/0x520 [ 33.199331] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 33.204492] RIP: 0033:0x440b38 [ 33.207744] RSP: 002b:00007fffdd3eb888 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 33.215424] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b38 [ 33.222682] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 33.229924] RBP: 00000000004c6fd0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 33.237166] R10: 0000000020000002 R11: 0000000000000246 R12: 0000000000000001 [ 33.244411] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 33.252347] Kernel Offset: 0x2e800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 33.263244] Rebooting in 86400 seconds..