[ 11.293204] random: sshd: uninitialized urandom read (32 bytes read) [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 29.555891] random: sshd: uninitialized urandom read (32 bytes read) [ 29.775750] audit: type=1400 audit(1569044786.112:6): avc: denied { map } for pid=1771 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 [ 29.808979] random: sshd: uninitialized urandom read (32 bytes read) [ 30.334881] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.106' (ECDSA) to the list of known hosts. [ 35.982843] urandom_read: 1 callbacks suppressed [ 35.982847] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 36.091906] audit: type=1400 audit(1569044792.432:7): avc: denied { map } for pid=1789 comm="syz-executor162" path="/root/syz-executor162266734" dev="sda1" ino=16482 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 36.095926] ================================================================== [ 36.125714] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x19d/0x1f0 [ 36.132502] Read of size 2 at addr ffff8881d0394f30 by task syz-executor162/1789 [ 36.140093] [ 36.141704] CPU: 0 PID: 1789 Comm: syz-executor162 Not tainted 4.14.145+ #0 [ 36.148779] Call Trace: [ 36.151506] dump_stack+0xca/0x134 [ 36.155133] ? tcp_init_tso_segs+0x19d/0x1f0 [ 36.159649] ? tcp_init_tso_segs+0x19d/0x1f0 [ 36.164044] print_address_description+0x60/0x226 [ 36.168953] ? tcp_init_tso_segs+0x19d/0x1f0 [ 36.173430] ? tcp_init_tso_segs+0x19d/0x1f0 [ 36.177818] __kasan_report.cold+0x1a/0x41 [ 36.182035] ? kvm_guest_cpu_init+0x220/0x220 [ 36.186506] ? tcp_init_tso_segs+0x19d/0x1f0 [ 36.190895] tcp_init_tso_segs+0x19d/0x1f0 [ 36.195119] ? tcp_tso_segs+0x7b/0x1c0 [ 36.198986] tcp_write_xmit+0x15a/0x4730 [ 36.203030] ? ip6_mtu+0x206/0x330 [ 36.206561] ? lock_downgrade+0x5d0/0x5d0 [ 36.210702] ? lock_acquire+0x12b/0x360 [ 36.214770] __tcp_push_pending_frames+0xa0/0x230 [ 36.219607] tcp_send_fin+0x154/0xbc0 [ 36.223400] tcp_close+0xc62/0xf40 [ 36.226926] ? lock_acquire+0x12b/0x360 [ 36.230892] ? __sock_release+0x86/0x2c0 [ 36.234947] inet_release+0xe9/0x1c0 [ 36.238642] inet6_release+0x4c/0x70 [ 36.242351] __sock_release+0xd2/0x2c0 [ 36.246217] ? __sock_release+0x2c0/0x2c0 [ 36.250354] sock_close+0x15/0x20 [ 36.253872] __fput+0x25e/0x710 [ 36.257138] task_work_run+0x125/0x1a0 [ 36.261014] do_exit+0x9cb/0x2a20 [ 36.264511] ? mm_update_next_owner+0x610/0x610 [ 36.269174] ? SyS_socket+0x143/0x1e0 [ 36.272968] do_group_exit+0x100/0x2e0 [ 36.276861] SyS_exit_group+0x19/0x20 [ 36.280733] ? do_group_exit+0x2e0/0x2e0 [ 36.284782] do_syscall_64+0x19b/0x520 [ 36.288659] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 36.293832] RIP: 0033:0x43ee88 [ 36.297001] RSP: 002b:00007ffcf8a09338 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 36.304826] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee88 [ 36.312273] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 36.319565] RBP: 00000000004be688 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 36.326817] R10: 0000000020000004 R11: 0000000000000246 R12: 0000000000000001 [ 36.334076] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 [ 36.341336] [ 36.342944] Allocated by task 1789: [ 36.346571] __kasan_kmalloc.part.0+0x53/0xc0 [ 36.351052] kmem_cache_alloc+0xee/0x360 [ 36.355101] __alloc_skb+0xea/0x5c0 [ 36.358705] sk_stream_alloc_skb+0xf4/0x8a0 [ 36.363006] tcp_sendmsg_locked+0xf11/0x2f50 [ 36.367427] tcp_sendmsg+0x2b/0x40 [ 36.370967] inet_sendmsg+0x15b/0x520 [ 36.374754] sock_sendmsg+0xb7/0x100 [ 36.378461] SyS_sendto+0x1de/0x2f0 [ 36.382083] do_syscall_64+0x19b/0x520 [ 36.385970] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 36.391149] 0xffffffffffffffff [ 36.394404] [ 36.396010] Freed by task 1789: [ 36.399280] __kasan_slab_free+0x164/0x210 [ 36.403507] kmem_cache_free+0xd7/0x3b0 [ 36.407461] kfree_skbmem+0x84/0x110 [ 36.411154] tcp_remove_empty_skb+0x264/0x320 [ 36.415639] tcp_sendmsg_locked+0x1c09/0x2f50 [ 36.420323] tcp_sendmsg+0x2b/0x40 [ 36.423862] inet_sendmsg+0x15b/0x520 [ 36.427836] sock_sendmsg+0xb7/0x100 [ 36.431615] SyS_sendto+0x1de/0x2f0 [ 36.435232] do_syscall_64+0x19b/0x520 [ 36.439111] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 36.444298] 0xffffffffffffffff [ 36.447553] [ 36.449172] The buggy address belongs to the object at ffff8881d0394f00 [ 36.449172] which belongs to the cache skbuff_fclone_cache of size 456 [ 36.463318] The buggy address is located 48 bytes inside of [ 36.463318] 456-byte region [ffff8881d0394f00, ffff8881d03950c8) [ 36.475098] The buggy address belongs to the page: [ 36.480009] page:ffffea000740e500 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 36.489967] flags: 0x4000000000010200(slab|head) [ 36.494700] raw: 4000000000010200 0000000000000000 0000000000000000 00000001800c000c [ 36.502562] raw: dead000000000100 dead000000000200 ffff8881dab70400 0000000000000000 [ 36.510419] page dumped because: kasan: bad access detected [ 36.516114] [ 36.517719] Memory state around the buggy address: [ 36.522637] ffff8881d0394e00: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc [ 36.529972] ffff8881d0394e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 36.537323] >ffff8881d0394f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 36.544660] ^ [ 36.549736] ffff8881d0394f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 36.557105] ffff8881d0395000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 36.564638] ================================================================== [ 36.572326] Disabling lock debugging due to kernel taint [ 36.578822] Kernel panic - not syncing: panic_on_warn set ... [ 36.578822] [ 36.586203] CPU: 0 PID: 1789 Comm: syz-executor162 Tainted: G B 4.14.145+ #0 [ 36.594509] Call Trace: [ 36.597082] dump_stack+0xca/0x134 [ 36.600635] panic+0x1ea/0x3d3 [ 36.603805] ? add_taint.cold+0x16/0x16 [ 36.607756] ? tcp_init_tso_segs+0x19d/0x1f0 [ 36.612143] ? ___preempt_schedule+0x16/0x18 [ 36.616545] ? tcp_init_tso_segs+0x19d/0x1f0 [ 36.621126] end_report+0x43/0x49 [ 36.624574] ? tcp_init_tso_segs+0x19d/0x1f0 [ 36.628967] __kasan_report.cold+0xd/0x41 [ 36.633112] ? kvm_guest_cpu_init+0x220/0x220 [ 36.637586] ? tcp_init_tso_segs+0x19d/0x1f0 [ 36.641977] tcp_init_tso_segs+0x19d/0x1f0 [ 36.646199] ? tcp_tso_segs+0x7b/0x1c0 [ 36.650101] tcp_write_xmit+0x15a/0x4730 [ 36.654845] ? ip6_mtu+0x206/0x330 [ 36.658362] ? lock_downgrade+0x5d0/0x5d0 [ 36.662488] ? lock_acquire+0x12b/0x360 [ 36.666442] __tcp_push_pending_frames+0xa0/0x230 [ 36.671270] tcp_send_fin+0x154/0xbc0 [ 36.675054] tcp_close+0xc62/0xf40 [ 36.678584] ? lock_acquire+0x12b/0x360 [ 36.682537] ? __sock_release+0x86/0x2c0 [ 36.686576] inet_release+0xe9/0x1c0 [ 36.690269] inet6_release+0x4c/0x70 [ 36.693963] __sock_release+0xd2/0x2c0 [ 36.697918] ? __sock_release+0x2c0/0x2c0 [ 36.702041] sock_close+0x15/0x20 [ 36.705480] __fput+0x25e/0x710 [ 36.708743] task_work_run+0x125/0x1a0 [ 36.712650] do_exit+0x9cb/0x2a20 [ 36.716100] ? mm_update_next_owner+0x610/0x610 [ 36.720833] ? SyS_socket+0x143/0x1e0 [ 36.724611] do_group_exit+0x100/0x2e0 [ 36.728476] SyS_exit_group+0x19/0x20 [ 36.732250] ? do_group_exit+0x2e0/0x2e0 [ 36.736290] do_syscall_64+0x19b/0x520 [ 36.740169] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 36.745336] RIP: 0033:0x43ee88 [ 36.748589] RSP: 002b:00007ffcf8a09338 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 36.756277] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee88 [ 36.763577] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 36.771020] RBP: 00000000004be688 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 36.778389] R10: 0000000020000004 R11: 0000000000000246 R12: 0000000000000001 [ 36.785787] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 [ 36.794258] Kernel Offset: 0xd400000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 36.805168] Rebooting in 86400 seconds..