[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[   18.312653] random: sshd: uninitialized urandom read (32 bytes read)
[?25l[?1c7[ ok 8[?25h[?0c.

Debian GNU/Linux 7 syzkaller ttyS0

syzkaller login: [   22.727708] random: sshd: uninitialized urandom read (32 bytes read)
[   23.048658] random: sshd: uninitialized urandom read (32 bytes read)
[   23.896230] random: sshd: uninitialized urandom read (32 bytes read)
[   38.210784] random: sshd: uninitialized urandom read (32 bytes read)
Warning: Permanently added '10.128.10.58' (ECDSA) to the list of known hosts.
[   43.627201] random: sshd: uninitialized urandom read (32 bytes read)
executing program
[   48.735158] ==================================================================
[   48.742676] BUG: KASAN: use-after-free in _copy_to_user+0xe9/0x110
[   48.748987] Read of size 924 at addr ffff8801a7fffff2 by task syz-executor308/4527
[   48.756677] 
[   48.758289] CPU: 1 PID: 4527 Comm: syz-executor308 Not tainted 4.18.0-rc3+ #137
[   48.765711] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   48.775041] Call Trace:
[   48.777618]  dump_stack+0x1c9/0x2b4
[   48.781226]  ? dump_stack_print_info.cold.2+0x52/0x52
[   48.786398]  ? printk+0xa7/0xcf
[   48.789666]  ? kmsg_dump_rewind_nolock+0xe4/0xe4
[   48.794405]  ? _copy_to_user+0xe9/0x110
[   48.798363]  print_address_description+0x6c/0x20b
[   48.803192]  ? _copy_to_user+0xe9/0x110
[   48.807145]  kasan_report.cold.7+0x242/0x2fe
[   48.811537]  check_memory_region+0x13e/0x1b0
[   48.815927]  kasan_check_read+0x11/0x20
[   48.819907]  _copy_to_user+0xe9/0x110
[   48.823731]  bpf_test_finish.isra.7+0xee/0x1f0
[   48.828301]  ? bpf_test_init.isra.8+0x100/0x100
[   48.832950]  ? bpf_test_run+0x2c0/0x3b0
[   48.836907]  ? bpf_test_run+0xed/0x3b0
[   48.840786]  ? bpf_test_run+0x2fc/0x3b0
[   48.844755]  bpf_prog_test_run_skb+0x7d7/0xa30
[   48.849319]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   48.854153]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   48.859668]  ? __bpf_prog_get+0x9b/0x290
[   48.863711]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   48.868528]  bpf_prog_test_run+0x130/0x1a0
[   48.872741]  __x64_sys_bpf+0x3d8/0x510
[   48.876607]  ? bpf_prog_get+0x20/0x20
[   48.880389]  ? setxattr+0x450/0x450
[   48.884003]  ? do_syscall_64+0x9a/0x820
[   48.887960]  do_syscall_64+0x1b9/0x820
[   48.891828]  ? syscall_return_slowpath+0x5e0/0x5e0
[   48.896738]  ? syscall_return_slowpath+0x31d/0x5e0
[   48.901658]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   48.907177]  ? retint_user+0x18/0x18
[   48.910875]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   48.915714]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   48.920884] RIP: 0033:0x441269
[   48.924053] Code: e8 8c b3 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00 
[   48.943223] RSP: 002b:00007ffeac2cfb48 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
[   48.950911] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441269
[   48.958159] RDX: 0000000000000028 RSI: 0000000020000140 RDI: 000000000000000a
[   48.965411] RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
[   48.972671] R10: 00000000004002c8 R11: 0000000000000213 R12: 0000000000402730
[   48.979920] R13: 00000000004027c0 R14: 0000000000000000 R15: 0000000000000000
[   48.987177] 
[   48.988779] The buggy address belongs to the page:
[   48.993697] page:ffffea00069fffc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
[   49.001827] flags: 0x2fffc0000000000()
[   49.005697] raw: 02fffc0000000000 ffffea00069fffc8 ffffea00069fffc8 0000000000000000
[   49.013566] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[   49.021422] page dumped because: kasan: bad access detected
[   49.027107] 
[   49.028710] Memory state around the buggy address:
[   49.033617]  ffff8801a7fffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   49.040954]  ffff8801a7ffff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   49.048303] >ffff8801a7ffff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   49.055640]                                                              ^
[   49.062632]  ffff8801a8000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   49.069968]  ffff8801a8000080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   49.077328] ==================================================================
[   49.084672] Disabling lock debugging due to kernel taint
[   49.090183] Kernel panic - not syncing: panic_on_warn set ...
[   49.090183] 
[   49.097557] CPU: 1 PID: 4527 Comm: syz-executor308 Tainted: G    B             4.18.0-rc3+ #137
[   49.106391] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   49.115733] Call Trace:
[   49.118305]  dump_stack+0x1c9/0x2b4
[   49.121913]  ? dump_stack_print_info.cold.2+0x52/0x52
[   49.127086]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   49.131822]  panic+0x238/0x4e7
[   49.134994]  ? add_taint.cold.5+0x16/0x16
[   49.139127]  ? do_raw_spin_unlock+0xa7/0x2f0
[   49.143512]  ? do_raw_spin_unlock+0xa7/0x2f0
[   49.147900]  ? _copy_to_user+0xe9/0x110
[   49.151852]  kasan_end_report+0x47/0x4f
[   49.155814]  kasan_report.cold.7+0x76/0x2fe
[   49.160117]  check_memory_region+0x13e/0x1b0
[   49.164504]  kasan_check_read+0x11/0x20
[   49.168454]  _copy_to_user+0xe9/0x110
[   49.172245]  bpf_test_finish.isra.7+0xee/0x1f0
[   49.176806]  ? bpf_test_init.isra.8+0x100/0x100
[   49.181466]  ? bpf_test_run+0x2c0/0x3b0
[   49.185421]  ? bpf_test_run+0xed/0x3b0
[   49.189290]  ? bpf_test_run+0x2fc/0x3b0
[   49.193247]  bpf_prog_test_run_skb+0x7d7/0xa30
[   49.197815]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   49.202641]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   49.208172]  ? __bpf_prog_get+0x9b/0x290
[   49.212251]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   49.217097]  bpf_prog_test_run+0x130/0x1a0
[   49.221332]  __x64_sys_bpf+0x3d8/0x510
[   49.225206]  ? bpf_prog_get+0x20/0x20
[   49.228987]  ? setxattr+0x450/0x450
[   49.232598]  ? do_syscall_64+0x9a/0x820
[   49.236554]  do_syscall_64+0x1b9/0x820
[   49.240420]  ? syscall_return_slowpath+0x5e0/0x5e0
[   49.245328]  ? syscall_return_slowpath+0x31d/0x5e0
[   49.250254]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   49.255772]  ? retint_user+0x18/0x18
[   49.259467]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   49.264290]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   49.269461] RIP: 0033:0x441269
[   49.272625] Code: e8 8c b3 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00 
[   49.291751] RSP: 002b:00007ffeac2cfb48 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
[   49.299440] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441269
[   49.306699] RDX: 0000000000000028 RSI: 0000000020000140 RDI: 000000000000000a
[   49.313946] RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
[   49.321193] R10: 00000000004002c8 R11: 0000000000000213 R12: 0000000000402730
[   49.328439] R13: 00000000004027c0 R14: 0000000000000000 R15: 0000000000000000
[   49.336199] Dumping ftrace buffer:
[   49.339719]    (ftrace buffer empty)
[   49.343403] Kernel Offset: disabled
[   49.347014] Rebooting in 86400 seconds..