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SubjectRe: [PATCH] HID: core: fix validation of report id 0
From
Pinging on this patch... I don't see it in -next yet. I've had more
reports of trouble with logitech devices, and this seems to solve the
problem.

-Kees

On Thu, Apr 17, 2014 at 1:22 PM, Kees Cook <keescook@chromium.org> wrote:
> Some drivers use the first HID report in the list instead of using an
> index. In these cases, validation uses ID 0, which was supposed to mean
> "first known report". This fixes the problem, which was causing at least
> the lgff family of devices to stop working since hid_validate_values
> was being called with ID 0, but the devices used single numbered IDs
> for their reports:
>
> 0x05, 0x01, /* Usage Page (Desktop), */
> 0x09, 0x05, /* Usage (Gamepad), */
> 0xA1, 0x01, /* Collection (Application), */
> 0xA1, 0x02, /* Collection (Logical), */
> 0x85, 0x01, /* Report ID (1), */
> ...
>
> Reported-by: Simon Wood <simon@mungewell.org>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Cc: stable@vger.kernel.org
> ---
> drivers/hid/hid-core.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 9e8064205bc7..07ce28175168 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -839,7 +839,17 @@ struct hid_report *hid_validate_values(struct hid_device *hid,
> * ->numbered being checked, which may not always be the case when
> * drivers go to access report values.
> */
> - report = hid->report_enum[type].report_id_hash[id];
> + if (id == 0) {
> + /*
> + * Validating on id 0 means we should examine the first
> + * report in the list.
> + */
> + report = list_entry(
> + hid->report_enum[type].report_list.next,
> + struct hid_report, list);
> + } else {
> + report = hid->report_enum[type].report_id_hash[id];
> + }
> if (!report) {
> hid_err(hid, "missing %s %u\n", hid_report_names[type], id);
> return NULL;
> --
> 1.7.9.5
>
>
> --
> Kees Cook
> Chrome OS Security



--
Kees Cook
Chrome OS Security


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