Re: [PATCH] HID: input: allocate input_dev name/phys/uniq using hid device devres

[chlgustn3171]

Adding maintainers and mailing list to CC. Sorry for the omission.

On Tue, Jul 14, 2026 at 10:33 PM chlgustn3171 <chlgustn3171@xxxxxxxxx> wrote:
>
> On Tue, Jul 14, 2026 at 9:18 PM sashiko-bot wrote:
> > [Severity: High]
> > If a userspace process holds an open file descriptor for the evdev node
> > (/dev/input/eventX), the input_dev will outlive the parent hid->dev.
> > When the HID device is unbound, devres will free these strings.
> >
> > Can this cause a use-after-free when userspace later queries the
> > name, phys, or uniq strings via ioctl (e.g., EVIOCGNAME)?
>
> Thanks for the review.
>
> Using &hid->dev here is intentional.
> Using the input device for devm-managed input_dev strings is
> problematic; see CVE-2023-53454, where the allocation was moved to the
> HID device because the input device unregister path may still use the
> name for uevents.
>
> > [Severity: Low]
> > If devm_kstrdup() fails for phys or uniq, the code jumps here to the
> > error path. The earlier successful devm_kstrdup() allocations remain
> > tied to &hid->dev.
> >
> > If the caller continues the device probe successfully after this failure,
> > will these strings be leaked for the lifetime of the HID device?
>
> The name/phys/uniq copies are attached to &hid->dev, so the clean-up
> is handled by HID device devres.
> However, if it is better to explicitly unwind, I can add that in v2.
>
> Thanks,
> Hyeonsu