[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 18.258542] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.289197] random: sshd: uninitialized urandom read (32 bytes read) [ 23.669887] random: sshd: uninitialized urandom read (32 bytes read) [ 24.538975] random: sshd: uninitialized urandom read (32 bytes read) [ 24.696194] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.7' (ECDSA) to the list of known hosts. [ 30.198272] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 35.296186] ================================================================== [ 35.303661] BUG: KASAN: use-after-free in _copy_to_user+0xe9/0x110 [ 35.310009] Read of size 924 at addr ffff8801a6fffff2 by task syz-executor356/4523 [ 35.317699] [ 35.319335] CPU: 1 PID: 4523 Comm: syz-executor356 Not tainted 4.18.0-rc4+ #139 [ 35.326812] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.336155] Call Trace: [ 35.338730] dump_stack+0x1c9/0x2b4 [ 35.342338] ? dump_stack_print_info.cold.2+0x52/0x52 [ 35.347511] ? printk+0xa7/0xcf [ 35.350772] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 35.355511] ? _copy_to_user+0xe9/0x110 [ 35.359465] print_address_description+0x6c/0x20b [ 35.364307] ? _copy_to_user+0xe9/0x110 [ 35.368266] kasan_report.cold.7+0x242/0x2fe [ 35.372654] check_memory_region+0x13e/0x1b0 [ 35.377041] kasan_check_read+0x11/0x20 [ 35.380992] _copy_to_user+0xe9/0x110 [ 35.384782] bpf_test_finish.isra.7+0xee/0x1f0 [ 35.389353] ? bpf_test_init.isra.8+0x100/0x100 [ 35.394003] ? bpf_test_run+0xdf/0x3b0 [ 35.397870] ? bpf_test_run+0x2fc/0x3b0 [ 35.401837] bpf_prog_test_run_skb+0x7d7/0xa30 [ 35.406424] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.411256] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.416777] ? __bpf_prog_get+0x9b/0x290 [ 35.420828] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.425649] bpf_prog_test_run+0x130/0x1a0 [ 35.429865] __x64_sys_bpf+0x3d8/0x510 [ 35.433737] ? bpf_prog_get+0x20/0x20 [ 35.437522] ? do_syscall_64+0x9a/0x820 [ 35.441489] do_syscall_64+0x1b9/0x820 [ 35.445356] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.450261] ? syscall_return_slowpath+0x31d/0x5e0 [ 35.455184] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.460724] ? retint_user+0x18/0x18 [ 35.464434] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.469266] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.474447] RIP: 0033:0x4408d9 [ 35.477612] Code: e8 4c b2 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 [ 35.496780] RSP: 002b:00007ffef15bdd18 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 35.504467] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004408d9 [ 35.511714] RDX: 0000000000000028 RSI: 0000000020000140 RDI: 000000000000000a [ 35.518975] RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8 [ 35.526230] R10: 0000000000c97880 R11: 0000000000000213 R12: 0000000000401da0 [ 35.533493] R13: 0000000000401e30 R14: 0000000000000000 R15: 0000000000000000 [ 35.540753] [ 35.542364] The buggy address belongs to the page: [ 35.547285] page:ffffea00069bffc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0 [ 35.555404] flags: 0x2fffc0000000000() [ 35.559273] raw: 02fffc0000000000 ffffea00069bffc8 ffffea00069bffc8 0000000000000000 [ 35.567147] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 35.575007] page dumped because: kasan: bad access detected [ 35.580693] [ 35.582295] Memory state around the buggy address: [ 35.587202] ffff8801a6fffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 35.594540] ffff8801a6ffff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 35.601874] >ffff8801a6ffff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 35.609211] ^ [ 35.616216] ffff8801a7000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 35.623568] ffff8801a7000080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 35.630923] ================================================================== [ 35.638262] Disabling lock debugging due to kernel taint [ 35.643763] Kernel panic - not syncing: panic_on_warn set ... [ 35.643763] [ 35.651119] CPU: 1 PID: 4523 Comm: syz-executor356 Tainted: G B 4.18.0-rc4+ #139 [ 35.659944] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.669276] Call Trace: [ 35.671852] dump_stack+0x1c9/0x2b4 [ 35.675460] ? dump_stack_print_info.cold.2+0x52/0x52 [ 35.680640] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 35.685382] panic+0x238/0x4e7 [ 35.688557] ? add_taint.cold.5+0x16/0x16 [ 35.692686] ? do_raw_spin_unlock+0xa7/0x2f0 [ 35.697071] ? do_raw_spin_unlock+0xa7/0x2f0 [ 35.701470] ? _copy_to_user+0xe9/0x110 [ 35.705431] kasan_end_report+0x47/0x4f [ 35.709383] kasan_report.cold.7+0x76/0x2fe [ 35.713685] check_memory_region+0x13e/0x1b0 [ 35.718073] kasan_check_read+0x11/0x20 [ 35.722038] _copy_to_user+0xe9/0x110 [ 35.725818] bpf_test_finish.isra.7+0xee/0x1f0 [ 35.730380] ? bpf_test_init.isra.8+0x100/0x100 [ 35.735041] ? bpf_test_run+0xdf/0x3b0 [ 35.738911] ? bpf_test_run+0x2fc/0x3b0 [ 35.742879] bpf_prog_test_run_skb+0x7d7/0xa30 [ 35.747444] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.752268] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.757783] ? __bpf_prog_get+0x9b/0x290 [ 35.761821] ? bpf_test_finish.isra.7+0x1f0/0x1f0 [ 35.766640] bpf_prog_test_run+0x130/0x1a0 [ 35.770856] __x64_sys_bpf+0x3d8/0x510 [ 35.774723] ? bpf_prog_get+0x20/0x20 [ 35.778504] ? do_syscall_64+0x9a/0x820 [ 35.782462] do_syscall_64+0x1b9/0x820 [ 35.786350] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.791257] ? syscall_return_slowpath+0x31d/0x5e0 [ 35.796165] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.801707] ? retint_user+0x18/0x18 [ 35.805416] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.810255] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.815429] RIP: 0033:0x4408d9 [ 35.818594] Code: e8 4c b2 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 [ 35.837713] RSP: 002b:00007ffef15bdd18 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 [ 35.845400] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004408d9 [ 35.852647] RDX: 0000000000000028 RSI: 0000000020000140 RDI: 000000000000000a [ 35.859895] RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8 [ 35.867143] R10: 0000000000c97880 R11: 0000000000000213 R12: 0000000000401da0 [ 35.874390] R13: 0000000000401e30 R14: 0000000000000000 R15: 0000000000000000 [ 35.882227] Dumping ftrace buffer: [ 35.885766] (ftrace buffer empty) [ 35.889456] Kernel Offset: disabled [ 35.893065] Rebooting in 86400 seconds..