[syzbot ci] Re: nfc: nci: fix uninit-value in nci_core_init_rsp_packet()

[syzbot ci]

syzbot ci has tested the following series

[v1] nfc: nci: fix uninit-value in nci_core_init_rsp_packet()
https://lore.kernel.org/all/2026062322240...@bynar.io
* [PATCH net] nfc: nci: fix uninit-value in nci_core_init_rsp_packet()

and found the following issue:
UBSAN: array-index-out-of-bounds in nci_init_complete_req

Full report is available here:
https://ci.syzbot.org/series/2a9a8657-37a3-4dce-8cb5-2035027791dd

***

UBSAN: array-index-out-of-bounds in nci_init_complete_req

tree: linux-next
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next
base: a986fde914d88af47eb78fd29c5d1af7952c3500
arch: amd64
compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config: https://ci.syzbot.org/builds/80f835c3-e998-47ff-aaa5-24c578af3b4e/config
syz repro: https://ci.syzbot.org/findings/65008893-2498-4786-b913-f2c474a7b34a/syz_repro

------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in net/nfc/nci/core.c:192:7
index 4 is out of range for type '__u8[4]' (aka 'unsigned char[4]')
CPU: 0 UID: 0 PID: 5905 Comm: syz.1.33 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
__ubsan_handle_out_of_bounds+0xe8/0xf0 lib/ubsan.c:455
nci_init_complete_req+0x255/0x460 net/nfc/nci/core.c:192
__nci_request+0x7d/0x300 net/nfc/nci/core.c:108
nci_open_device net/nfc/nci/core.c:529 [inline]
nci_dev_up+0x8c3/0xdc0 net/nfc/nci/core.c:643
nfc_dev_up+0x165/0x350 net/nfc/core.c:118
nfc_genl_dev_up+0x89/0xe0 net/nfc/netlink.c:775
genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:775 [inline]
__sock_sendmsg net/socket.c:790 [inline]
____sys_sendmsg+0x9b9/0xa20 net/socket.c:2684
___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
__sys_sendmsg net/socket.c:2770 [inline]
__do_sys_sendmsg net/socket.c:2775 [inline]
__se_sys_sendmsg net/socket.c:2773 [inline]
__x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f55ead9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f55ebcb9028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f55eb015fa0 RCX: 00007f55ead9ce59
RDX: 0000000004008054 RSI: 0000200000000200 RDI: 0000000000000005
RBP: 00007f55eae32e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f55eb016038 R14: 00007f55eb015fa0 R15: 00007ffcba11c798
</TASK>
---[ end trace ]---


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syz...@syzkaller.appspotmail.com

---
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[Sam P]

On 24/06/2026 09:13, syzbot ci wrote:
> syzbot ci has tested the following series
>
> [v1] nfc: nci: fix uninit-value in nci_core_init_rsp_packet()
> https://lore.kernel.org/all/2026062322240...@bynar.io
> * [PATCH net] nfc: nci: fix uninit-value in nci_core_init_rsp_packet()
>
> and found the following issue:
> UBSAN: array-index-out-of-bounds in nci_init_complete_req
>
> Full report is available here:
> https://ci.syzbot.org/series/2a9a8657-37a3-4dce-8cb5-2035027791dd

Oops, looks like this patch did indeed introduce a regression due to bad
check ordering. I have a v2 prepared, tested against the syzbot repro and
NCI selftest which I will submit after the ~24h patch resend period is up.

Thanks,
Sam