[....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.615327] 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: [ 21.957194] random: sshd: uninitialized urandom read (32 bytes read) [ 22.364549] random: sshd: uninitialized urandom read (32 bytes read) [ 23.263083] random: sshd: uninitialized urandom read (32 bytes read) [ 29.471186] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.5' (ECDSA) to the list of known hosts. [ 34.969494] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 35.094493] ================================================================== [ 35.101968] BUG: KASAN: use-after-free in _copy_to_user+0xe9/0x110 [ 35.108280] Read of size 1006 at addr ffff8801a6fffff2 by task syz-executor739/4540 [ 35.116051] [ 35.117667] CPU: 1 PID: 4540 Comm: syz-executor739 Not tainted 4.18.0-rc4+ #139 [ 35.125100] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.134452] Call Trace: [ 35.137044] dump_stack+0x1c9/0x2b4 [ 35.140659] ? dump_stack_print_info.cold.2+0x52/0x52 [ 35.145829] ? printk+0xa7/0xcf [ 35.149089] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 35.153831] ? _copy_to_user+0xe9/0x110 [ 35.157798] print_address_description+0x6c/0x20b [ 35.162623] ? _copy_to_user+0xe9/0x110 [ 35.166577] kasan_report.cold.7+0x242/0x2fe [ 35.170977] check_memory_region+0x13e/0x1b0 [ 35.175370] kasan_check_read+0x11/0x20 [ 35.179329] _copy_to_user+0xe9/0x110 [ 35.183114] bpf_test_finish.isra.7+0xee/0x1f0 [ 35.187680] ? bpf_test_init.isra.8+0x100/0x100 [ 35.192336] ? bpf_test_run+0x2fc/0x3b0 [ 35.196307] bpf_prog_test_run_skb+0x7d7/0xa30 [ 35.200874] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.205701] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.211225] ? __bpf_prog_get+0x9b/0x290 [ 35.215273] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.220096] bpf_prog_test_run+0x130/0x1a0 [ 35.224316] __x64_sys_bpf+0x3d8/0x510 [ 35.228197] ? bpf_prog_get+0x20/0x20 [ 35.231993] ? do_syscall_64+0x9a/0x820 [ 35.235958] do_syscall_64+0x1b9/0x820 [ 35.239828] ? syscall_slow_exit_work+0x500/0x500 [ 35.244656] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.249578] ? syscall_return_slowpath+0x31d/0x5e0 [ 35.254495] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 35.259844] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.264682] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.269855] RIP: 0033:0x440319 [ 35.273027] 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 [ 35.292209] RSP: 002b:00007ffc4546d4c8 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 35.299901] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440319 [ 35.307160] RDX: 0000000000000028 RSI: 00000000200001c0 RDI: 000000000000000a [ 35.314409] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 35.321667] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ba0 [ 35.328918] R13: 0000000000401c30 R14: 0000000000000000 R15: 0000000000000000 [ 35.336177] [ 35.337782] The buggy address belongs to the page: [ 35.342690] page:ffffea00069bffc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0 [ 35.350817] flags: 0x2fffc0000000000() [ 35.354686] raw: 02fffc0000000000 ffffea00069bffc8 ffffea00069bffc8 0000000000000000 [ 35.362549] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 35.370413] page dumped because: kasan: bad access detected [ 35.376097] [ 35.377699] Memory state around the buggy address: [ 35.382613] ffff8801a6fffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 35.389963] ffff8801a6ffff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 35.397316] >ffff8801a6ffff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 35.404659] ^ [ 35.411661] ffff8801a7000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 35.419016] ffff8801a7000080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 35.426393] ================================================================== [ 35.433734] Disabling lock debugging due to kernel taint [ 35.439257] Kernel panic - not syncing: panic_on_warn set ... [ 35.439257] [ 35.446615] CPU: 1 PID: 4540 Comm: syz-executor739 Tainted: G B 4.18.0-rc4+ #139 [ 35.455425] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.464753] Call Trace: [ 35.467323] dump_stack+0x1c9/0x2b4 [ 35.470931] ? dump_stack_print_info.cold.2+0x52/0x52 [ 35.476101] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 35.480849] panic+0x238/0x4e7 [ 35.484029] ? add_taint.cold.5+0x16/0x16 [ 35.488161] ? do_raw_spin_unlock+0xa7/0x2f0 [ 35.492554] ? do_raw_spin_unlock+0xa7/0x2f0 [ 35.496944] ? _copy_to_user+0xe9/0x110 [ 35.500898] kasan_end_report+0x47/0x4f [ 35.504854] kasan_report.cold.7+0x76/0x2fe [ 35.509168] check_memory_region+0x13e/0x1b0 [ 35.513584] kasan_check_read+0x11/0x20 [ 35.517574] _copy_to_user+0xe9/0x110 [ 35.521384] bpf_test_finish.isra.7+0xee/0x1f0 [ 35.525964] ? bpf_test_init.isra.8+0x100/0x100 [ 35.530633] ? bpf_test_run+0x2fc/0x3b0 [ 35.534609] bpf_prog_test_run_skb+0x7d7/0xa30 [ 35.539193] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.544035] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.549568] ? __bpf_prog_get+0x9b/0x290 [ 35.553632] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.558468] bpf_prog_test_run+0x130/0x1a0 [ 35.562809] __x64_sys_bpf+0x3d8/0x510 [ 35.566686] ? bpf_prog_get+0x20/0x20 [ 35.570479] ? do_syscall_64+0x9a/0x820 [ 35.574439] do_syscall_64+0x1b9/0x820 [ 35.578307] ? syscall_slow_exit_work+0x500/0x500 [ 35.583127] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.588034] ? syscall_return_slowpath+0x31d/0x5e0 [ 35.592944] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 35.598286] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.603109] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.608277] RIP: 0033:0x440319 [ 35.611441] 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 [ 35.630562] RSP: 002b:00007ffc4546d4c8 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 35.638256] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440319 [ 35.645503] RDX: 0000000000000028 RSI: 00000000200001c0 RDI: 000000000000000a [ 35.652749] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 35.659999] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ba0 [ 35.667246] R13: 0000000000401c30 R14: 0000000000000000 R15: 0000000000000000 [ 35.674888] Dumping ftrace buffer: [ 35.678403] (ftrace buffer empty) [ 35.682098] Kernel Offset: disabled [ 35.685702] Rebooting in 86400 seconds..