[RAMEN9610-22013]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.

Change-Id: I96857aa2e17b88d900a50aa16a016f4aca6b1fa5
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>

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 6395a8863f730ee1c7bdba5a1442020b23d712cd..70af0f25969e4b1784fdf106db9e801ebbd84841 100644 (file)
--- 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;
 
@@ -253,7 +253,7 @@ 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;