Re: [syzbot] [hwmon?] KASAN: slab-out-of-bounds Read in aqc_raw_event

[Aleksa Savic <savicaleksa83@gmail.com>]

On 8/22/26 6:02 AM, Guenter Roeck wrote:
> Aleksa,
> 
> On 8/21/26 20:06, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit:    e1e6e541c5c9 Merge tag 'thunderbolt-for-v7.3-rc1' of 
>> ssh:/..
>> git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/ 
>> gregkh/usb.git usb-testing
>> console output: https://syzkaller.appspot.com/x/log.txt?x=16086e79580000
>> kernel config:  https://syzkaller.appspot.com/x/.config? 
>> x=8bdeea7ee6735f91
>> dashboard link: https://syzkaller.appspot.com/bug? 
>> extid=9ee5f5dc18673d6b2f37
>> compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils 
>> for Debian) 2.44
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz? 
>> x=14737679580000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15a22549580000
>>
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/3b0a1f8e6a1f/ 
>> disk-e1e6e541.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/f98d855e85e8/ 
>> vmlinux-e1e6e541.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/ 
>> db2c3a41df6d/bzImage-e1e6e541.xz
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the 
>> commit:
>> Reported-by: syzbot+9ee5f5dc18673d6b2f37@syzkaller.appspotmail.com
>>
>> ==================================================================
>> BUG: KASAN: slab-out-of-bounds in get_unaligned_be16 include/linux/ 
>> unaligned.h:48 [inline]
>> BUG: KASAN: slab-out-of-bounds in aqc_raw_event drivers/hwmon/ 
>> aquacomputer_d5next.c:1345 [inline]
>> BUG: KASAN: slab-out-of-bounds in aqc_raw_event+0x213e/0x25d0 drivers/ 
>> hwmon/aquacomputer_d5next.c:1327
> 
> The problem is that syzkaller sends a bad (short) report.
> aqc_raw_event() needs to validate the report size and bail out
> if it is short. The fix should be straightforard if it is known
> what the minimum report size is. D5NEXT_CTRL_REPORT_SIZE ?
> 
> Thanks,
> Guenter

We do know sizes of control (setting) reports since we send them through 
priv->buffer, but aqc_raw_event() gets sensor reports and their length 
can vary per device. I don't have an exact list for all devices since I 
don't have them all myself. We'll need to verify that what we receive in 
aqc_raw_event() is >= the minimum offset we want to read sensor values from.

Thanks,
Aleksa