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Commit 33332177 authored by Will McVicker's avatar Will McVicker Committed by shaohanlin
Browse files

HID: make arrays usage and value to be the same 



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: default avatarWill McVicker <willmcvicker@google.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit b12d3930)
parent 7b909dce

drivers/hid/hid-core.c

+3 −3
Original line number Original line Diff line number Diff line
@@ -91,7 +91,7 @@ EXPORT_SYMBOL_GPL(hid_register_report); 
 * Register a new field for this 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;

	struct hid_field *field;
@@ -102,7 +102,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned 




	field = kzalloc((sizeof(struct hid_field) +

	field = kzalloc((sizeof(struct hid_field) +

			 usages * sizeof(struct hid_usage) +

			 usages * sizeof(struct hid_usage) +

			 values * sizeof(unsigned)), GFP_KERNEL);

			 usages * sizeof(unsigned)), GFP_KERNEL);

	if (!field)

	if (!field)

		return NULL;

		return NULL;
@@ -281,7 +281,7 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign 
	usages = max_t(unsigned, parser->local.usage_index,

	usages = max_t(unsigned, parser->local.usage_index,

				 parser->global.report_count);

				 parser->global.report_count);





	field = hid_register_field(report, usages, parser->global.report_count);

	field = hid_register_field(report, usages);

	if (!field)

	if (!field)

		return 0;

		return 0;