[syzbot] [mm?] [hardening?] BUG: bad usercopy in do_handle_open

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    c0b832517f62 Add linux-next specific files for 20240402
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13a5c3b1180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=afcaf46d374cec8c
dashboard link: https://syzkaller.appspot.com/bug?extid=4372e026c95b0e36d0ee
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16ed9d29180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=161ab3c6180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0d36ec76edc7/disk-c0b83251.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6f9bb4e37dd0/vmlinux-c0b83251.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2349287b14b7/bzImage-c0b83251.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4372e026c95b0e36d0ee@xxxxxxxxxxxxxxxxxxxxxxxxx

usercopy: Kernel memory overwrite attempt detected to SLUB object 'kmalloc-16' (offset 8, size 9)!
------------[ cut here ]------------
kernel BUG at mm/usercopy.c:102!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 5081 Comm: syz-executor249 Not tainted 6.9.0-rc2-next-20240402-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:usercopy_abort+0x84/0x90 mm/usercopy.c:102
Code: 49 89 ce 48 c7 c3 e0 27 d8 8b 48 0f 44 de 48 c7 c7 80 26 d8 8b 4c 89 de 48 89 c1 41 52 41 56 53 e8 b1 6f 75 09 48 83 c4 18 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003dbfd78 EFLAGS: 00010286
RAX: 0000000000000062 RBX: ffffffff8bd827e0 RCX: 2b2ecef8eabe4800
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000008 R08: ffffffff81760b9c R09: 1ffff920007b7f4c
R10: dffffc0000000000 R11: fffff520007b7f4d R12: ffffea00008fe840
R13: 0000000000000009 R14: 0000000000000008 R15: 0000000000000009
FS:  000055556aa78380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000040 CR3: 0000000076e74000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __check_heap_object+0xb1/0x100 mm/slub.c:5461
 check_heap_object mm/usercopy.c:196 [inline]
 __check_object_size+0x1e3/0x900 mm/usercopy.c:251
 check_object_size include/linux/thread_info.h:215 [inline]
 check_copy_size include/linux/thread_info.h:251 [inline]
 copy_from_user include/linux/uaccess.h:182 [inline]
 handle_to_path fs/fhandle.c:203 [inline]
 do_handle_open+0x1f6/0x660 fs/fhandle.c:226
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x72/0x7a
RIP: 0033:0x7f27665352a9
Code: 48 83 c4 28 c3 e8 37 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe7e4589d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000130
RAX: ffffffffffffffda RBX: 00007ffe7e458bb8 RCX: 00007f27665352a9
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 00000000ffffffff
RBP: 00007f27665a8610 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffe7e458ba8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:usercopy_abort+0x84/0x90 mm/usercopy.c:102
Code: 49 89 ce 48 c7 c3 e0 27 d8 8b 48 0f 44 de 48 c7 c7 80 26 d8 8b 4c 89 de 48 89 c1 41 52 41 56 53 e8 b1 6f 75 09 48 83 c4 18 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003dbfd78 EFLAGS: 00010286
RAX: 0000000000000062 RBX: ffffffff8bd827e0 RCX: 2b2ecef8eabe4800
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000008 R08: ffffffff81760b9c R09: 1ffff920007b7f4c
R10: dffffc0000000000 R11: fffff520007b7f4d R12: ffffea00008fe840
R13: 0000000000000009 R14: 0000000000000008 R15: 0000000000000009
FS:  000055556aa78380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000040 CR3: 0000000076e74000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup