[syzbot] [lsm?] WARNING in landlock_merge_ruleset

[syzbot <syzbot+a0eecb22de4d821a9e5d@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    aac26bee2287 Add linux-next specific files for 20261008
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1772f715580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=814b0d31d59c294
dashboard link: https://syzkaller.appspot.com/bug?extid=a0eecb22de4d821a9e5d
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1305c8e1580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15497c3e580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/92e867ba9905/disk-aac26bee.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c4cc176072c1/vmlinux-aac26bee.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c603638afe28/bzImage-aac26bee.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a0eecb22de4d821a9e5d@syzkaller.appspotmail.com

------------[ cut here ]------------
memcpy: detected buffer overflow: 16 byte read of buffer size 0
WARNING: lib/string_helpers.c:1037 at __fortify_report+0x6b/0xa0 lib/string_helpers.c:1036, CPU#0: syz-executor347/5624
Modules linked in:
CPU: 0 UID: 0 PID: 5624 Comm: syz-executor347 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:__fortify_report+0x89/0xa0 lib/string_helpers.c:1036
Code: e8 ec f1 4b fd 48 8d 3d c5 7e d7 0c 45 84 e4 49 8b 37 48 c7 c0 40 8d 8d 8c 48 c7 c1 60 8d 8d 8c 48 0f 44 c8 4c 89 f2 49 89 d8 <67> 48 0f b9 3a 5b 41 5c 41 5e 41 5f 5d e9 45 84 14 07 cc cc cc cc
RSP: 0018:ffffc90003bb7dc8 EFLAGS: 00010246
RAX: ffffffff8c8d8d40 RBX: 0000000000000000 RCX: ffffffff8c8d8d40
RDX: 0000000000000010 RSI: ffffffff8c8d8c20 RDI: ffffffff91c743f0
RBP: 000000000000000e R08: 0000000000000000 R09: 1ffff11006d9ed01
R10: dffffc0000000000 R11: ffffed1006d9ed02 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000010 R15: ffffffff8c8d8a78
FS:  000055558b41f400(0000) GS:ffff888123429000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c55f793000 CR3: 00000000359c2000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __fortify_panic+0x9/0x10 lib/string_helpers.c:1043
 fortify_memcpy_chk include/linux/fortify-string.h:547 [inline]
 inherit_ruleset security/landlock/domain.c:407 [inline]
 landlock_merge_ruleset+0xc46/0xc90 security/landlock/domain.c:468
 __do_sys_landlock_restrict_self security/landlock/syscalls.c:809 [inline]
 __se_sys_landlock_restrict_self+0x2bc/0xd40 security/landlock/syscalls.c:732
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc0d85c8c39
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff6fcb7858 EFLAGS: 00000246 ORIG_RAX: 00000000000001be
RAX: ffffffffffffffda RBX: 00007fff6fcb7988 RCX: 00007fc0d85c8c39
RDX: 00007fc0d85c8c39 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000001 R08: 00007fff6fcb7988 R09: 00007fff6fcb7988
R10: 00007fff6fcb7988 R11: 0000000000000246 R12: 00007fff6fcb7978
R13: 0000000000000002 R14: 00007fc0d8659ca0 R15: 0000000000000002
 </TASK>
----------------
Code disassembly (best guess):
   0:	e8 ec f1 4b fd       	call   0xfd4bf1f1
   5:	48 8d 3d c5 7e d7 0c 	lea    0xcd77ec5(%rip),%rdi        # 0xcd77ed1
   c:	45 84 e4             	test   %r12b,%r12b
   f:	49 8b 37             	mov    (%r15),%rsi
  12:	48 c7 c0 40 8d 8d 8c 	mov    $0xffffffff8c8d8d40,%rax
  19:	48 c7 c1 60 8d 8d 8c 	mov    $0xffffffff8c8d8d60,%rcx
  20:	48 0f 44 c8          	cmove  %rax,%rcx
  24:	4c 89 f2             	mov    %r14,%rdx
  27:	49 89 d8             	mov    %rbx,%r8
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	5b                   	pop    %rbx
  30:	41 5c                	pop    %r12
  32:	41 5e                	pop    %r14
  34:	41 5f                	pop    %r15
  36:	5d                   	pop    %rbp
  37:	e9 45 84 14 07       	jmp    0x7148481
  3c:	cc                   	int3
  3d:	cc                   	int3
  3e:	cc                   	int3
  3f:	cc                   	int3


---
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