HID: hiddev: validate num_values for HIDIOCGUSAGES, HIDIOCSUSAGES commands

This patch validates the num_values parameter from userland during the
HIDIOCGUSAGES and HIDIOCSUSAGES commands. Previously, if the report id was set
to HID_REPORT_ID_UNKNOWN, we would fail to validate the num_values parameter
leading to a heap overflow.

Cc: stable@vger.kernel.org
Signed-off-by: Scott Bauer <sbauer@plzdonthack.me>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 5 insertions, 5 deletions

diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index 2f1ddca6f2e0..700145b15088 100644
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -516,13 +516,13 @@ static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd,
                                         goto inval;
                         } else if (uref->usage_index >= field->report_count)
                                 goto inval;
-
-                        else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
-                                 (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
-                                  uref->usage_index + uref_multi->num_values > field->report_count))
-                                goto inval;
                 }
 
+                if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
+                    (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
+                     uref->usage_index + uref_multi->num_values > field->report_count))
+                        goto inval;
+
                 switch (cmd) {
                 case HIDIOCGUSAGE:
                         uref->value = field->value[uref->usage_index];