[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.118950] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 21.770326] random: sshd: uninitialized urandom read (32 bytes read) [ 22.016466] random: sshd: uninitialized urandom read (32 bytes read) [ 22.840834] random: sshd: uninitialized urandom read (32 bytes read) [ 29.414562] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.15.206' (ECDSA) to the list of known hosts. [ 34.902326] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 34.998747] ================================================================== [ 35.006285] BUG: KASAN: use-after-free in _copy_to_user+0xe9/0x110 [ 35.012593] Read of size 978 at addr ffff8801a7bffff2 by task syz-executor278/4560 [ 35.020288] [ 35.021902] CPU: 0 PID: 4560 Comm: syz-executor278 Not tainted 4.18.0-rc3+ #6 [ 35.029155] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.038490] Call Trace: [ 35.041064] dump_stack+0x1c9/0x2b4 [ 35.044673] ? dump_stack_print_info.cold.2+0x52/0x52 [ 35.049839] ? printk+0xa7/0xcf [ 35.053099] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 35.057839] ? _copy_to_user+0xe9/0x110 [ 35.061803] print_address_description+0x6c/0x20b [ 35.066625] ? _copy_to_user+0xe9/0x110 [ 35.070579] kasan_report.cold.7+0x242/0x2fe [ 35.074971] check_memory_region+0x13e/0x1b0 [ 35.079360] kasan_check_read+0x11/0x20 [ 35.083312] _copy_to_user+0xe9/0x110 [ 35.087113] bpf_test_finish.isra.7+0xee/0x1f0 [ 35.091678] ? bpf_test_init.isra.8+0x100/0x100 [ 35.096337] ? bpf_test_run+0x2fc/0x3b0 [ 35.100295] bpf_prog_test_run_skb+0x7d7/0xa30 [ 35.104859] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.109687] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.115206] ? __bpf_prog_get+0x9b/0x290 [ 35.119252] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.124076] bpf_prog_test_run+0x130/0x1a0 [ 35.128293] __x64_sys_bpf+0x3d8/0x510 [ 35.132161] ? bpf_prog_get+0x20/0x20 [ 35.135950] ? do_syscall_64+0x9a/0x820 [ 35.139906] do_syscall_64+0x1b9/0x820 [ 35.143776] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.148686] ? syscall_return_slowpath+0x31d/0x5e0 [ 35.153600] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 35.158946] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.163789] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.168971] RIP: 0033:0x440259 [ 35.172141] 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 [ 35.191320] RSP: 002b:00007ffe14f7d5d8 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 35.199012] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440259 [ 35.206262] RDX: 0000000000000028 RSI: 0000000020000280 RDI: 000000000000000a [ 35.213954] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 35.221200] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ae0 [ 35.228449] R13: 0000000000401b70 R14: 0000000000000000 R15: 0000000000000000 [ 35.235707] [ 35.237310] The buggy address belongs to the page: [ 35.242217] page:ffffea00069effc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0 [ 35.250338] flags: 0x2fffc0000000000() [ 35.254206] raw: 02fffc0000000000 ffffea00069effc8 ffffea00069effc8 0000000000000000 [ 35.262068] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 35.269933] page dumped because: kasan: bad access detected [ 35.275755] [ 35.277360] Memory state around the buggy address: [ 35.282285] ffff8801a7bffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 35.289624] ffff8801a7bfff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 35.296959] >ffff8801a7bfff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 35.304302] ^ [ 35.311289] ffff8801a7c00000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 35.318724] ffff8801a7c00080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 35.326068] ================================================================== [ 35.333400] Disabling lock debugging due to kernel taint [ 35.338894] Kernel panic - not syncing: panic_on_warn set ... [ 35.338894] [ 35.346241] CPU: 0 PID: 4560 Comm: syz-executor278 Tainted: G B 4.18.0-rc3+ #6 [ 35.354877] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.364216] Call Trace: [ 35.366787] dump_stack+0x1c9/0x2b4 [ 35.370401] ? dump_stack_print_info.cold.2+0x52/0x52 [ 35.375591] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 35.380329] panic+0x238/0x4e7 [ 35.383499] ? add_taint.cold.5+0x16/0x16 [ 35.387629] ? do_raw_spin_unlock+0xa7/0x2f0 [ 35.392015] ? do_raw_spin_unlock+0xa7/0x2f0 [ 35.396402] ? _copy_to_user+0xe9/0x110 [ 35.400352] kasan_end_report+0x47/0x4f [ 35.404314] kasan_report.cold.7+0x76/0x2fe [ 35.408616] check_memory_region+0x13e/0x1b0 [ 35.413017] kasan_check_read+0x11/0x20 [ 35.416972] _copy_to_user+0xe9/0x110 [ 35.420757] bpf_test_finish.isra.7+0xee/0x1f0 [ 35.425315] ? bpf_test_init.isra.8+0x100/0x100 [ 35.429966] ? bpf_test_run+0x2fc/0x3b0 [ 35.433925] bpf_prog_test_run_skb+0x7d7/0xa30 [ 35.438487] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.443317] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.448829] ? __bpf_prog_get+0x9b/0x290 [ 35.452877] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.457696] bpf_prog_test_run+0x130/0x1a0 [ 35.461919] __x64_sys_bpf+0x3d8/0x510 [ 35.465782] ? bpf_prog_get+0x20/0x20 [ 35.469652] ? do_syscall_64+0x9a/0x820 [ 35.473606] do_syscall_64+0x1b9/0x820 [ 35.477473] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.482387] ? syscall_return_slowpath+0x31d/0x5e0 [ 35.487300] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 35.492655] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.497491] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.502660] RIP: 0033:0x440259 [ 35.505831] 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 [ 35.524953] RSP: 002b:00007ffe14f7d5d8 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 35.532639] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440259 [ 35.539887] RDX: 0000000000000028 RSI: 0000000020000280 RDI: 000000000000000a [ 35.547135] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 35.554558] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ae0 [ 35.561810] R13: 0000000000401b70 R14: 0000000000000000 R15: 0000000000000000 [ 35.569516] Dumping ftrace buffer: [ 35.573044] (ftrace buffer empty) [ 35.576734] Kernel Offset: disabled [ 35.580352] Rebooting in 86400 seconds..