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HID: make arrays usage and value to be the same 

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>
This commit is contained in:
Will McVicker 2020-12-05 00:48:48 +00:00 committed by Jiri Kosina
parent a0312af1f9
commit ed9be64eef
1 changed files with 3 additions and 3 deletions
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6
drivers/hid/hid-core.c
View File

@ -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;