[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 11.351220] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 32.550574] random: sshd: uninitialized urandom read (32 bytes read) [ 32.872665] audit: type=1400 audit(1569057660.257:6): avc: denied { map } for pid=1773 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 [ 32.903133] random: sshd: uninitialized urandom read (32 bytes read) [ 33.405804] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.19' (ECDSA) to the list of known hosts. [ 38.963631] urandom_read: 1 callbacks suppressed [ 38.963635] random: sshd: uninitialized urandom read (32 bytes read) [ 39.060638] audit: type=1400 audit(1569057666.447:7): avc: denied { map } for pid=1785 comm="syz-executor457" path="/root/syz-executor457435086" 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 executing program [ 39.830839] ================================================================== [ 39.838306] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x19d/0x1f0 [ 39.845038] Read of size 2 at addr ffff8881d66471b0 by task syz-executor457/1786 [ 39.852576] [ 39.854184] CPU: 0 PID: 1786 Comm: syz-executor457 Not tainted 4.14.145+ #0 [ 39.861255] Call Trace: [ 39.863824] dump_stack+0xca/0x134 [ 39.867342] ? tcp_init_tso_segs+0x19d/0x1f0 [ 39.871729] ? tcp_init_tso_segs+0x19d/0x1f0 [ 39.876132] print_address_description+0x60/0x226 [ 39.880974] ? tcp_init_tso_segs+0x19d/0x1f0 [ 39.885358] ? tcp_init_tso_segs+0x19d/0x1f0 [ 39.889741] __kasan_report.cold+0x1a/0x41 [ 39.893958] ? kvm_guest_cpu_init+0x220/0x220 [ 39.898446] ? tcp_init_tso_segs+0x19d/0x1f0 [ 39.902830] tcp_init_tso_segs+0x19d/0x1f0 [ 39.907038] ? tcp_tso_segs+0x7b/0x1c0 [ 39.910906] tcp_write_xmit+0x15a/0x4730 [ 39.914950] ? memset+0x20/0x40 [ 39.918223] __tcp_push_pending_frames+0xa0/0x230 [ 39.923248] tcp_send_fin+0x154/0xbc0 [ 39.927028] tcp_close+0xc62/0xf40 [ 39.930554] inet_release+0xe9/0x1c0 [ 39.934248] __sock_release+0xd2/0x2c0 [ 39.938111] ? __sock_release+0x2c0/0x2c0 [ 39.942232] sock_close+0x15/0x20 [ 39.945672] __fput+0x25e/0x710 [ 39.948940] task_work_run+0x125/0x1a0 [ 39.952811] do_exit+0x9cb/0x2a20 [ 39.956262] ? mm_update_next_owner+0x610/0x610 [ 39.960918] do_group_exit+0x100/0x2e0 [ 39.964783] SyS_exit_group+0x19/0x20 [ 39.968559] ? do_group_exit+0x2e0/0x2e0 [ 39.972613] do_syscall_64+0x19b/0x520 [ 39.976484] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 39.981649] RIP: 0033:0x440b48 [ 39.984830] RSP: 002b:00007ffeb08dc088 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 39.992517] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b48 [ 39.999786] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 40.007035] RBP: 00000000004c6fd0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 40.014298] R10: 0000000020000800 R11: 0000000000000246 R12: 0000000000000001 [ 40.021543] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 40.028801] [ 40.030425] Allocated by task 1786: [ 40.034044] __kasan_kmalloc.part.0+0x53/0xc0 [ 40.038517] kmem_cache_alloc+0xee/0x360 [ 40.042555] __alloc_skb+0xea/0x5c0 [ 40.046162] sk_stream_alloc_skb+0xf4/0x8a0 [ 40.050463] tcp_sendmsg_locked+0xf11/0x2f50 [ 40.054852] tcp_sendmsg+0x2b/0x40 [ 40.058370] inet_sendmsg+0x15b/0x520 [ 40.062149] sock_sendmsg+0xb7/0x100 [ 40.065840] SyS_sendto+0x1de/0x2f0 [ 40.069443] do_syscall_64+0x19b/0x520 [ 40.073309] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 40.078476] 0xffffffffffffffff [ 40.081819] [ 40.083424] Freed by task 1786: [ 40.086679] __kasan_slab_free+0x164/0x210 [ 40.090892] kmem_cache_free+0xd7/0x3b0 [ 40.094864] kfree_skbmem+0x84/0x110 [ 40.098565] tcp_remove_empty_skb+0x264/0x320 [ 40.103052] tcp_sendmsg_locked+0x1c09/0x2f50 [ 40.107525] tcp_sendmsg+0x2b/0x40 [ 40.111043] inet_sendmsg+0x15b/0x520 [ 40.114820] sock_sendmsg+0xb7/0x100 [ 40.118521] SyS_sendto+0x1de/0x2f0 [ 40.122123] do_syscall_64+0x19b/0x520 [ 40.125987] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 40.131237] 0xffffffffffffffff [ 40.134490] [ 40.136095] The buggy address belongs to the object at ffff8881d6647180 [ 40.136095] which belongs to the cache skbuff_fclone_cache of size 456 [ 40.149418] The buggy address is located 48 bytes inside of [ 40.149418] 456-byte region [ffff8881d6647180, ffff8881d6647348) [ 40.161178] The buggy address belongs to the page: [ 40.166082] page:ffffea0007599180 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 40.176025] flags: 0x4000000000010200(slab|head) [ 40.180759] raw: 4000000000010200 0000000000000000 0000000000000000 00000001800c000c [ 40.188616] raw: dead000000000100 dead000000000200 ffff8881dab70400 0000000000000000 [ 40.196468] page dumped because: kasan: bad access detected [ 40.202157] [ 40.203760] Memory state around the buggy address: [ 40.208668] ffff8881d6647080: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc [ 40.216003] ffff8881d6647100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 40.223351] >ffff8881d6647180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 40.230685] ^ [ 40.235590] ffff8881d6647200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 40.243183] ffff8881d6647280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 40.250517] ================================================================== [ 40.257848] Disabling lock debugging due to kernel taint [ 40.263561] Kernel panic - not syncing: panic_on_warn set ... [ 40.263561] [ 40.270916] CPU: 0 PID: 1786 Comm: syz-executor457 Tainted: G B 4.14.145+ #0 [ 40.279204] Call Trace: [ 40.281773] dump_stack+0xca/0x134 [ 40.285292] panic+0x1ea/0x3d3 [ 40.288458] ? add_taint.cold+0x16/0x16 [ 40.292407] ? tcp_init_tso_segs+0x19d/0x1f0 [ 40.296791] ? ___preempt_schedule+0x16/0x18 [ 40.301174] ? tcp_init_tso_segs+0x19d/0x1f0 [ 40.305570] end_report+0x43/0x49 [ 40.308995] ? tcp_init_tso_segs+0x19d/0x1f0 [ 40.313377] __kasan_report.cold+0xd/0x41 [ 40.317499] ? kvm_guest_cpu_init+0x220/0x220 [ 40.321966] ? tcp_init_tso_segs+0x19d/0x1f0 [ 40.326362] tcp_init_tso_segs+0x19d/0x1f0 [ 40.330569] ? tcp_tso_segs+0x7b/0x1c0 [ 40.334434] tcp_write_xmit+0x15a/0x4730 [ 40.338473] ? memset+0x20/0x40 [ 40.341731] __tcp_push_pending_frames+0xa0/0x230 [ 40.346560] tcp_send_fin+0x154/0xbc0 [ 40.350338] tcp_close+0xc62/0xf40 [ 40.353859] inet_release+0xe9/0x1c0 [ 40.357561] __sock_release+0xd2/0x2c0 [ 40.361437] ? __sock_release+0x2c0/0x2c0 [ 40.365773] sock_close+0x15/0x20 [ 40.369203] __fput+0x25e/0x710 [ 40.372461] task_work_run+0x125/0x1a0 [ 40.376325] do_exit+0x9cb/0x2a20 [ 40.379774] ? mm_update_next_owner+0x610/0x610 [ 40.384421] do_group_exit+0x100/0x2e0 [ 40.388285] SyS_exit_group+0x19/0x20 [ 40.392146] ? do_group_exit+0x2e0/0x2e0 [ 40.396181] do_syscall_64+0x19b/0x520 [ 40.400046] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 40.405209] RIP: 0033:0x440b48 [ 40.408372] RSP: 002b:00007ffeb08dc088 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 40.416066] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440b48 [ 40.423310] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 40.430554] RBP: 00000000004c6fd0 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 40.437797] R10: 0000000020000800 R11: 0000000000000246 R12: 0000000000000001 [ 40.445154] R13: 00000000006d95e0 R14: 0000000000000000 R15: 0000000000000000 [ 40.453037] Kernel Offset: 0x2b200000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 40.463932] Rebooting in 86400 seconds..