Re: [PATCH] HID: usbhid: replace strlcat with better alternatives

[Jiri Kosina]

On Fri, 10 Apr 2026, Mahad Ibrahim wrote:

> In preparation for the removal of the strlcat() API as per the KSPP,
> replace the string concatenation logic in hid-core, usbkbd, and
> usbmouse with struct seq_buf, which tracks the current write position
> and remaining space internally. The changes implemented include:
> 
> - Replace device name and phys concatenation with seq_buf_puts().
> - Include Struct seq_buf and its initialization.
> - Include header file of seq_buf.
> - Replace strlen() with seq_buf_used() on the string buffer which was
>   tracked by seq_buf to increase speed.
> - Add size_t len in files which did not have it.
> - Use of strscpy with length in place of strlcat.
> 
> Testing: This driver was compiled as a module as well as in-built in
> QEMU with the QEMU basic mouse, and QEMU basic keyboard. The testing was
> done in the following steps.
> - Add Hardware Mouse in QEMU checking the usbhid module.
> - Verify dmesg string name of mouse.
> - Blacklist hidusb module from auto-loading, and removing the module via
>   rmmod.
> - Load usbmouse module, and reattach QEMU mouse.
> - Verify dmesg string name of mouse.
> - Repeat same procedure on usbkbd module.
> 
> This aligns the driver with KSPP security guidelines.
> 
> Link: https://github.com/KSPP/linux/issues/370
> 
> Signed-off-by: Mahad Ibrahim <mahad.ibrahim.dev@xxxxxxxxx>

Applied, thanks.

-- 
Jiri Kosina
SUSE Labs