[PATCH 5.10 02/23] HID: make arrays usage and value to be the same

Greg Kroah-Hartman
2021-02-25T10:07:32Z

From: Will McVicker <willmcvicker@google.com>

commit ed9be64eefe26d7d8b0b5b9fa3ffdf425d87a01f upstream.

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.

Cc: stable@vger.kernel.org
Signed-off-by: Will McVicker <willmcvicker@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hid/hid-core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- 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_fi

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_pars
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;