On Sat, Dec 05, 2020 at 12:48:48AM +0000, Will McVicker wrote:
> The HID subsystem allows an "HID report field" to have a different
> number of "values" and "usages" when it is allocated. When a field
> struct is created, the size of the usage array is guaranteed to be at
> least as large as the values array, but it may be larger. This leads to
> a potential out-of-bounds write in
> __hidinput_change_resolution_multipliers() and an out-of-bounds read in
> hidinput_count_leds().
>
> To fix this, let's make sure that both the usage and value arrays are
> the same size.
>
> Signed-off-by: Will McVicker <willmcvicker@xxxxxxxxxx>
> ---
> drivers/hid/hid-core.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 56172fe6995c..8a8b2b982f83 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -90,7 +90,7 @@ EXPORT_SYMBOL_GPL(hid_register_report);
> * Register a new field for this report.
> */
>
> -static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
> +static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages)
> {
> struct hid_field *field;
>
> @@ -101,7 +101,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned
>
> field = kzalloc((sizeof(struct hid_field) +
> usages * sizeof(struct hid_usage) +
> - values * sizeof(unsigned)), GFP_KERNEL);
> + usages * sizeof(unsigned)), GFP_KERNEL);
> if (!field)
> return NULL;
>
> @@ -300,7 +300,7 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign
> usages = max_t(unsigned, parser->local.usage_index,
> parser->global.report_count);
>
> - field = hid_register_field(report, usages, parser->global.report_count);
> + field = hid_register_field(report, usages);
> if (!field)
> return 0;
>
> --
> 2.29.2.576.ga3fc446d84-goog
>
Hi Jiri and Benjamin,
This is a friendly reminder in case this got lost in your inbox.
Thanks,
Will
