HID: hiddev: validate num_values for HIDIOCGUSAGES, HIDIOCSUSAGES commands
authorScott Bauer <sbauer@plzdonthack.me>
Thu, 23 Jun 2016 14:59:47 +0000 (08:59 -0600)
committerJiri Kosina <jkosina@suse.cz>
Fri, 24 Jun 2016 08:21:39 +0000 (10:21 +0200)
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>
drivers/hid/usbhid/hiddev.c

index 2f1ddca6f2e0a3a4712bce434d5b29e1556e216c..700145b1508894f30a018aef278d15cfc458ef3a 100644 (file)
@@ -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];