urandom_read: 1 callbacks suppressed random: sshd: uninitialized urandom read (32 bytes read) random: cc1: uninitialized urandom read (8 bytes read) ip (3171) used greatest stack depth: 23608 bytes left ================================================================== BUG: KASAN: use-after-free in _copy_to_user+0x9a/0xc0 lib/usercopy.c:27 Read of size 1435 at addr ffff8801c67ffffc by task syz-executor3/5563 CPU: 0 PID: 5563 Comm: syz-executor3 Not tainted 4.14.67+ #1 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 print_address_description+0x60/0x22b mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report.cold.6+0x11b/0x2dd mm/kasan/report.c:409 _copy_to_user+0x9a/0xc0 lib/usercopy.c:27 copy_to_user include/linux/uaccess.h:155 [inline] bpf_test_finish.isra.0+0xc8/0x190 net/bpf/test_run.c:59 bpf_prog_test_run_skb+0x4d0/0x8c0 net/bpf/test_run.c:144 bpf_prog_test_run kernel/bpf/syscall.c:1330 [inline] SYSC_bpf kernel/bpf/syscall.c:1602 [inline] SyS_bpf+0x79d/0x3640 kernel/bpf/syscall.c:1547 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457099 RSP: 002b:00007f85c212ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f85c212f6d4 RCX: 0000000000457099 RDX: 0000000000000028 RSI: 0000000020000080 RDI: 000000000000000a RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004cb680 R14: 00000000004c3071 R15: 0000000000000000 The buggy address belongs to the page: page:ffffea000719ffc0 count:0 mapcount:0 mapping: (null) index:0x1 flags: 0x4000000000000000() raw: 4000000000000000 0000000000000000 0000000000000001 00000000ffffffff raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c67ffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8801c67fff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8801c67fff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8801c6800000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801c6800080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================