[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 17.762809] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.355155] random: sshd: uninitialized urandom read (32 bytes read) [ 22.673606] random: sshd: uninitialized urandom read (32 bytes read) [ 23.575149] random: sshd: uninitialized urandom read (32 bytes read) [ 25.851140] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.37' (ECDSA) to the list of known hosts. [ 31.355275] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 31.462574] ================================================================== [ 31.470018] BUG: KASAN: use-after-free in _copy_to_user+0xe9/0x110 [ 31.476325] Read of size 924 at addr ffff8801ab7ffff2 by task syz-executor173/4509 [ 31.484004] [ 31.485623] CPU: 1 PID: 4509 Comm: syz-executor173 Not tainted 4.18.0-rc4+ #144 [ 31.493054] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.502384] Call Trace: [ 31.504954] dump_stack+0x1c9/0x2b4 [ 31.508562] ? dump_stack_print_info.cold.2+0x52/0x52 [ 31.513729] ? printk+0xa7/0xcf [ 31.516993] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 31.521736] ? _copy_to_user+0xe9/0x110 [ 31.525689] print_address_description+0x6c/0x20b [ 31.530509] ? _copy_to_user+0xe9/0x110 [ 31.534464] kasan_report.cold.7+0x242/0x2fe [ 31.538854] check_memory_region+0x13e/0x1b0 [ 31.543255] kasan_check_read+0x11/0x20 [ 31.547210] _copy_to_user+0xe9/0x110 [ 31.551007] bpf_test_finish.isra.7+0xee/0x1f0 [ 31.555584] ? bpf_test_init.isra.8+0x100/0x100 [ 31.560249] ? write_comp_data+0x6c/0x70 [ 31.564301] ? bpf_test_run+0x2fc/0x3b0 [ 31.568261] bpf_prog_test_run_skb+0x7d7/0xa30 [ 31.572826] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 31.577652] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.583167] ? __bpf_prog_get+0x9b/0x290 [ 31.587209] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 31.592036] bpf_prog_test_run+0x130/0x1a0 [ 31.596259] __x64_sys_bpf+0x3d8/0x510 [ 31.600129] ? bpf_prog_get+0x20/0x20 [ 31.603912] ? do_syscall_64+0x9a/0x820 [ 31.607870] do_syscall_64+0x1b9/0x820 [ 31.611737] ? syscall_return_slowpath+0x5e0/0x5e0 [ 31.616646] ? syscall_return_slowpath+0x31d/0x5e0 [ 31.621556] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 31.626900] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.631728] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 31.636895] RIP: 0033:0x440269 [ 31.640064] 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 [ 31.659232] RSP: 002b:00007ffe962cae98 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 31.666919] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440269 [ 31.674170] RDX: 0000000000000028 RSI: 0000000020000180 RDI: 000000000000000a [ 31.681419] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 31.688667] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401af0 [ 31.695916] R13: 0000000000401b80 R14: 0000000000000000 R15: 0000000000000000 [ 31.703174] [ 31.704779] The buggy address belongs to the page: [ 31.709687] page:ffffea0006adffc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0 [ 31.717807] flags: 0x2fffc0000000000() [ 31.721676] raw: 02fffc0000000000 ffffea0006adffc8 ffffea0006adffc8 0000000000000000 [ 31.729568] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 31.737420] page dumped because: kasan: bad access detected [ 31.743111] [ 31.744713] Memory state around the buggy address: [ 31.749619] ffff8801ab7ffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 31.756952] ffff8801ab7fff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 31.764289] >ffff8801ab7fff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 31.771620] ^ [ 31.778608] ffff8801ab800000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 31.785945] ffff8801ab800080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 31.793285] ================================================================== [ 31.800622] Disabling lock debugging due to kernel taint [ 31.806116] Kernel panic - not syncing: panic_on_warn set ... [ 31.806116] [ 31.813481] CPU: 1 PID: 4509 Comm: syz-executor173 Tainted: G B 4.18.0-rc4+ #144 [ 31.822291] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.831627] Call Trace: [ 31.834197] dump_stack+0x1c9/0x2b4 [ 31.837808] ? dump_stack_print_info.cold.2+0x52/0x52 [ 31.842976] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 31.847720] panic+0x238/0x4e7 [ 31.850892] ? add_taint.cold.5+0x16/0x16 [ 31.855028] ? do_raw_spin_unlock+0xa7/0x2f0 [ 31.859421] ? do_raw_spin_unlock+0xa7/0x2f0 [ 31.863810] ? _copy_to_user+0xe9/0x110 [ 31.867767] kasan_end_report+0x47/0x4f [ 31.871718] kasan_report.cold.7+0x76/0x2fe [ 31.876029] check_memory_region+0x13e/0x1b0 [ 31.880420] kasan_check_read+0x11/0x20 [ 31.884377] _copy_to_user+0xe9/0x110 [ 31.888171] bpf_test_finish.isra.7+0xee/0x1f0 [ 31.892732] ? bpf_test_init.isra.8+0x100/0x100 [ 31.897377] ? write_comp_data+0x6c/0x70 [ 31.901416] ? bpf_test_run+0x2fc/0x3b0 [ 31.905370] bpf_prog_test_run_skb+0x7d7/0xa30 [ 31.909932] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 31.914750] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.920262] ? __bpf_prog_get+0x9b/0x290 [ 31.924300] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 31.929117] bpf_prog_test_run+0x130/0x1a0 [ 31.933330] __x64_sys_bpf+0x3d8/0x510 [ 31.937196] ? bpf_prog_get+0x20/0x20 [ 31.940977] ? do_syscall_64+0x9a/0x820 [ 31.944929] do_syscall_64+0x1b9/0x820 [ 31.948795] ? syscall_return_slowpath+0x5e0/0x5e0 [ 31.953709] ? syscall_return_slowpath+0x31d/0x5e0 [ 31.958622] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 31.963963] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.968785] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 31.973951] RIP: 0033:0x440269 [ 31.977112] 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 [ 31.996225] RSP: 002b:00007ffe962cae98 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 32.003917] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440269 [ 32.011165] RDX: 0000000000000028 RSI: 0000000020000180 RDI: 000000000000000a [ 32.018409] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 32.025656] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401af0 [ 32.032903] R13: 0000000000401b80 R14: 0000000000000000 R15: 0000000000000000 [ 32.040585] Dumping ftrace buffer: [ 32.044107] (ftrace buffer empty) [ 32.047800] Kernel Offset: disabled [ 32.051400] Rebooting in 86400 seconds..