Bug 1519535 - Check that deviceNumber is valid in GetDeviceName; r=jib

Differential Revision: https://phabricator.services.mozilla.com/D21945

--HG--
extra : moz-landing-system : lando

media/webrtc/trunk/webrtc/modules/video_capture/objc/device_info.mm

@@ -67,7 +67,10 @@ int32_t DeviceInfoIos::Init() {
 
     char deviceNameUTF8[256];
     char deviceId[256];
-    this->GetDeviceName(i, deviceNameUTF8, 256, deviceId, 256);
+    int error = this->GetDeviceName(i, deviceNameUTF8, 256, deviceId, 256);
+    if (error) {
+      return error;
+    }
     std::string deviceIdCopy(deviceId);
     std::pair<std::string, VideoCaptureCapabilities> mapPair =
         std::pair<std::string, VideoCaptureCapabilities>(deviceIdCopy, capabilityVector);
@@ -89,6 +92,11 @@ int32_t DeviceInfoIos::GetDeviceName(uint32_t deviceNumber,
                                      char* productUniqueIdUTF8,
                                      uint32_t productUniqueIdUTF8Length,
                                      pid_t* pid) {
+
+  if (deviceNumber >= NumberOfDevices()) {
+    return -1;
+  }
+
   NSString* deviceName = [DeviceInfoIosObjC deviceNameForIndex:deviceNumber];
 
   NSString* deviceUniqueId = [DeviceInfoIosObjC deviceUniqueIdForIndex:deviceNumber];