[....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.605959] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.733006] random: sshd: uninitialized urandom read (32 bytes read) [ 26.053156] random: sshd: uninitialized urandom read (32 bytes read) [ 26.937610] random: sshd: uninitialized urandom read (32 bytes read) [ 27.095528] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.40' (ECDSA) to the list of known hosts. [ 32.584818] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 32.703575] ================================================================== [ 32.711430] BUG: KASAN: use-after-free in _copy_to_user+0xe9/0x110 [ 32.718264] Read of size 1006 at addr ffff8801a83ffff2 by task syz-executor088/4569 [ 32.726050] [ 32.727694] CPU: 1 PID: 4569 Comm: syz-executor088 Not tainted 4.18.0-rc3+ #4 [ 32.734957] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.744310] Call Trace: [ 32.746891] dump_stack+0x1c9/0x2b4 [ 32.750504] ? dump_stack_print_info.cold.2+0x52/0x52 [ 32.755689] ? printk+0xa7/0xcf [ 32.758998] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 32.763758] ? _copy_to_user+0xe9/0x110 [ 32.767728] print_address_description+0x6c/0x20b [ 32.772589] ? _copy_to_user+0xe9/0x110 [ 32.776580] kasan_report.cold.7+0x242/0x2fe [ 32.781429] check_memory_region+0x13e/0x1b0 [ 32.786038] kasan_check_read+0x11/0x20 [ 32.790038] _copy_to_user+0xe9/0x110 [ 32.793849] bpf_test_finish.isra.7+0xee/0x1f0 [ 32.798427] ? bpf_test_init.isra.8+0x100/0x100 [ 32.803081] ? bpf_test_run+0x278/0x3b0 [ 32.807055] ? bpf_test_run+0x2fc/0x3b0 [ 32.811044] bpf_prog_test_run_skb+0x7d7/0xa30 [ 32.815632] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 32.820760] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.826308] ? __bpf_prog_get+0x9b/0x290 [ 32.830374] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 32.835212] bpf_prog_test_run+0x130/0x1a0 [ 32.839447] __x64_sys_bpf+0x3d8/0x510 [ 32.843325] ? bpf_prog_get+0x20/0x20 [ 32.847130] ? do_syscall_64+0x9a/0x820 [ 32.851101] do_syscall_64+0x1b9/0x820 [ 32.854993] ? syscall_return_slowpath+0x5e0/0x5e0 [ 32.859949] ? syscall_return_slowpath+0x31d/0x5e0 [ 32.864897] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 32.870275] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 32.875135] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 32.880327] RIP: 0033:0x440319 [ 32.883511] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 32.902765] RSP: 002b:00007ffec8f1ca18 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 32.910469] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440319 [ 32.917735] RDX: 0000000000000028 RSI: 00000000200001c0 RDI: 000000000000000a [ 32.925021] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 32.932298] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ba0 [ 32.939561] R13: 0000000000401c30 R14: 0000000000000000 R15: 0000000000000000 [ 32.946833] [ 32.948458] The buggy address belongs to the page: [ 32.953389] page:ffffea0006a0ffc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0 [ 32.961526] flags: 0x2fffc0000000000() [ 32.965412] raw: 02fffc0000000000 ffffea0006a0ffc8 ffffea0006a0ffc8 0000000000000000 [ 32.973290] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 32.981182] page dumped because: kasan: bad access detected [ 32.986881] [ 32.988503] Memory state around the buggy address: [ 32.993429] ffff8801a83ffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 33.000785] ffff8801a83fff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 33.008133] >ffff8801a83fff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 33.015482] ^ [ 33.022495] ffff8801a8400000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 33.029843] ffff8801a8400080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 33.037194] ================================================================== [ 33.044542] Disabling lock debugging due to kernel taint [ 33.050075] Kernel panic - not syncing: panic_on_warn set ... [ 33.050075] [ 33.057444] CPU: 1 PID: 4569 Comm: syz-executor088 Tainted: G B 4.18.0-rc3+ #4 [ 33.066099] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.075440] Call Trace: [ 33.078024] dump_stack+0x1c9/0x2b4 [ 33.081651] ? dump_stack_print_info.cold.2+0x52/0x52 [ 33.086836] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 33.091594] panic+0x238/0x4e7 [ 33.094771] ? add_taint.cold.5+0x16/0x16 [ 33.098915] ? do_raw_spin_unlock+0xa7/0x2f0 [ 33.103320] ? do_raw_spin_unlock+0xa7/0x2f0 [ 33.107731] ? _copy_to_user+0xe9/0x110 [ 33.111718] kasan_end_report+0x47/0x4f [ 33.115694] kasan_report.cold.7+0x76/0x2fe [ 33.120033] check_memory_region+0x13e/0x1b0 [ 33.124449] kasan_check_read+0x11/0x20 [ 33.128431] _copy_to_user+0xe9/0x110 [ 33.132221] bpf_test_finish.isra.7+0xee/0x1f0 [ 33.136790] ? bpf_test_init.isra.8+0x100/0x100 [ 33.141459] ? bpf_test_run+0x278/0x3b0 [ 33.145441] ? bpf_test_run+0x2fc/0x3b0 [ 33.149413] bpf_prog_test_run_skb+0x7d7/0xa30 [ 33.154000] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 33.158852] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 33.164404] ? __bpf_prog_get+0x9b/0x290 [ 33.168462] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 33.173302] bpf_prog_test_run+0x130/0x1a0 [ 33.177531] __x64_sys_bpf+0x3d8/0x510 [ 33.181424] ? bpf_prog_get+0x20/0x20 [ 33.185234] ? do_syscall_64+0x9a/0x820 [ 33.189207] do_syscall_64+0x1b9/0x820 [ 33.193094] ? syscall_return_slowpath+0x5e0/0x5e0 [ 33.198016] ? syscall_return_slowpath+0x31d/0x5e0 [ 33.202955] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 33.208317] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 33.213155] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.218327] RIP: 0033:0x440319 [ 33.221492] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 33.240629] RSP: 002b:00007ffec8f1ca18 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 33.248333] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440319 [ 33.255605] RDX: 0000000000000028 RSI: 00000000200001c0 RDI: 000000000000000a [ 33.262866] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 33.270141] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ba0 [ 33.277409] R13: 0000000000401c30 R14: 0000000000000000 R15: 0000000000000000 [ 33.285179] Dumping ftrace buffer: [ 33.288728] (ftrace buffer empty) [ 33.292427] Kernel Offset: disabled [ 33.296047] Rebooting in 86400 seconds..