[PATCH 4.9 001/134] HID: make arrays usage and value to be the same

[Greg Kroah-Hartman]

From: Will McVicker <willmcvic...@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: sta...@vger.kernel.org
Signed-off-by: Will McVicker <willmcvic...@google.com>
Signed-off-by: Jiri Kosina <jkos...@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gre...@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
@@ -91,7 +91,7 @@ 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;
 
@@ -102,7 +102,7 @@ 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;
 
@@ -281,7 +281,7 @@ 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;