[syzbot] [input?] [usb?] KASAN: slab-out-of-bounds Read in hid_dump_input

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0d8395707651 Merge tag 'soc-fixes-7.2-2' of git://git.kern..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1265cfb9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=3e8a402093abe6b2
dashboard link: https://syzkaller.appspot.com/bug?extid=a942efa43c928a1e3daa
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=13520fb9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15ccbe49580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/137c48a5e559/disk-0d839570.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7597f78ad1c4/vmlinux-0d839570.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1a79fc123166/bzImage-0d839570.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a942ef...@syzkaller.appspotmail.com

hid-picolcd 0003:04D8:C002.0001: offset (1) exceeds report_count (1)
==================================================================
BUG: KASAN: slab-out-of-bounds in hid_dump_input+0xcb/0xd0 drivers/hid/hid-debug.c:3132
Read of size 4 at addr ffff88802ab28fc0 by task kworker/1:2/48

CPU: 1 UID: 0 PID: 48 Comm: kworker/1:2 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events fb_deferred_io_work
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
hid_dump_input+0xcb/0xd0 drivers/hid/hid-debug.c:3132
hid_set_field+0xd3/0x440 drivers/hid/hid-core.c:1936
picolcd_fb_send_tile drivers/hid/hid-picolcd_fb.c:112 [inline]
picolcd_fb_update drivers/hid/hid-picolcd_fb.c:268 [inline]
picolcd_fb_deferred_io+0x6d5/0x1880 drivers/hid/hid-picolcd_fb.c:403
fb_deferred_io_work+0x1cf/0x310 drivers/video/fbdev/core/fb_defio.c:405
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>

Allocated by task 24:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5334 [inline]
__kvmalloc_node_noprof+0x53f/0x860 mm/slub.c:6905
hid_register_field drivers/hid/hid-core.c:133 [inline]
hid_add_field+0x70a/0x1840 drivers/hid/hid-core.c:340
hid_parser_main+0x2e1/0xd50 drivers/hid/hid-core.c:-1
hid_parse_collections drivers/hid/hid-core.c:1291 [inline]
hid_open_report+0x884/0xf00 drivers/hid/hid-core.c:1384
hid_parse include/linux/hid.h:1206 [inline]
picolcd_probe+0x177/0x16c0 drivers/hid/hid-picolcd_core.c:547
__hid_device_probe drivers/hid/hid-core.c:2829 [inline]
hid_device_probe+0x42c/0x7c0 drivers/hid/hid-core.c:2866
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x254/0xae0 drivers/base/dd.c:706
__driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
__device_attach_driver+0x270/0x410 drivers/base/dd.c:1026
bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
__device_attach+0x2c4/0x450 drivers/base/dd.c:1098
device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
bus_probe_device+0x12a/0x220 drivers/base/bus.c:620
device_add+0x7d7/0xb80 drivers/base/core.c:3772
hid_add_device+0x272/0x3e0 drivers/hid/hid-core.c:3010
usbhid_probe+0x9d4/0xde0 drivers/hid/usbhid/hid-core.c:1452
usb_probe_interface+0x653/0xc60 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x254/0xae0 drivers/base/dd.c:706
__driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
__device_attach_driver+0x270/0x410 drivers/base/dd.c:1026
bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
__device_attach+0x2c4/0x450 drivers/base/dd.c:1098
device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
bus_probe_device+0x12a/0x220 drivers/base/bus.c:620
device_add+0x7d7/0xb80 drivers/base/core.c:3772
usb_set_configuration+0x1ad8/0x2180 drivers/usb/core/message.c:2268
usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
usb_probe_device+0x1c3/0x3b0 drivers/usb/core/driver.c:291
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x254/0xae0 drivers/base/dd.c:706
__driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
__device_attach_driver+0x270/0x410 drivers/base/dd.c:1026
bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
__device_attach+0x2c4/0x450 drivers/base/dd.c:1098
device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
bus_probe_device+0x12a/0x220 drivers/base/bus.c:620
device_add+0x7d7/0xb80 drivers/base/core.c:3772
usb_new_device+0x99d/0x1620 drivers/usb/core/hub.c:2695
hub_port_connect drivers/usb/core/hub.c:5567 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
port_event drivers/usb/core/hub.c:5871 [inline]
hub_event+0x28e8/0x4d30 drivers/usb/core/hub.c:5953
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff88802ab28f00
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 16 bytes to the right of
allocated 176-byte region [ffff88802ab28f00, ffff88802ab28fb0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ab28
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88813fe3e3c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 12816571384, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
alloc_slab_page mm/slub.c:3266 [inline]
allocate_slab+0x79/0x5e0 mm/slub.c:3380
new_slab mm/slub.c:3426 [inline]
refill_objects+0x2d5/0x350 mm/slub.c:7310
refill_sheaf mm/slub.c:2804 [inline]
__pcs_replace_empty_main+0x2bf/0x6b0 mm/slub.c:4675
alloc_from_pcs mm/slub.c:4773 [inline]
slab_alloc_node mm/slub.c:4905 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kmalloc_noprof+0x485/0x720 mm/slub.c:5359
_kmalloc_noprof include/linux/slab.h:992 [inline]
usb_alloc_urb+0x46/0x150 drivers/usb/core/urb.c:75
usb_internal_control_msg drivers/usb/core/message.c:110 [inline]
usb_control_msg+0x118/0x3e0 drivers/usb/core/message.c:167
usb_get_string+0xa2/0x3e0 drivers/usb/core/message.c:902
usb_string_sub+0x76/0x420 drivers/usb/core/message.c:941
usb_string+0x34f/0x790 drivers/usb/core/message.c:1046
usb_cache_string+0x7d/0xf0 drivers/usb/core/message.c:1090
usb_enumerate_device drivers/usb/core/hub.c:2537 [inline]
usb_new_device+0x27c/0x1620 drivers/usb/core/hub.c:2665
register_root_hub+0x250/0x5c0 drivers/usb/core/hcd.c:990
usb_add_hcd+0xac7/0xf80 drivers/usb/core/hcd.c:2987
page_owner free stack trace missing

Memory state around the buggy address:
ffff88802ab28e80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
ffff88802ab28f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88802ab28f80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
^
ffff88802ab29000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88802ab29080: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc 00 00
==================================================================


---
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[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: [PATCH] HID: core: check field offset before dumping input
Author: karti...@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


hid_set_field() passes field->usage + offset to hid_dump_input() before
validating offset against field->report_count. field->usage is allocated
with exactly report_count entries, so a larger offset is read out of
bounds before the existing check rejects it:

BUG: KASAN: slab-out-of-bounds in hid_dump_input+0xcb/0xd0

Read of size 4 at addr ffff88802ab28fc0 by task kworker/1:2/48

Move the bounds check above the hid_dump_input() call so the function
returns before the dereference.

Reported-by: syzbot+a942ef...@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a942efa43c928a1e3daa
Signed-off-by: Deepanshu Kartikey <karti...@gmail.com>
---
drivers/hid/hid-core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index cf123347a2af..7ea1fb62b9d4 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1933,13 +1933,14 @@ int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)

size = field->report_size;

- hid_dump_input(field->report->device, field->usage + offset, value);
-
if (offset >= field->report_count) {
hid_err(field->report->device, "offset (%d) exceeds report_count (%d)\n",
offset, field->report_count);
return -1;
}
+
+ hid_dump_input(field->report->device, field->usage + offset, value);
+
if (field->logical_minimum < 0) {
if (value != snto32(s32ton(value, size), size)) {
hid_err(field->report->device, "value %d is out of range\n", value);
--
2.43.0

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+a942ef...@syzkaller.appspotmail.com
Tested-by: syzbot+a942ef...@syzkaller.appspotmail.com

Tested on:

commit: 06cf6189 Merge tag 'x86-urgent-2026-08-08' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13528149580000
kernel config: https://syzkaller.appspot.com/x/.config?x=aaf0da806f995318

dashboard link: https://syzkaller.appspot.com/bug?extid=a942efa43c928a1e3daa
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=157bbfb9580000

Note: testing is done by a robot and is best-effort only.