Darwin: Fix error handling in GetMACAddressFromInterfaces (project-chip#32658)

Correctly return CHIP_ERROR_NOT_FOUND when there is no active, primary
interface to get the MAC address from.

Also tidy up management of IOKit objects. (Use of IOObjectGetRetainCount is
completely wrong here.)

Author: ksperling-apple

src/platform/Darwin/ConfigurationManagerImpl.cpp

@@ -93,20 +93,20 @@ CHIP_ERROR FindInterfaces(io_iterator_t * primaryInterfaceIterator)
 
 CHIP_ERROR GetMACAddressFromInterfaces(io_iterator_t primaryInterfaceIterator, uint8_t * buf)
 {
-    CHIP_ERROR err = CHIP_NO_ERROR;
+    CHIP_ERROR err = CHIP_ERROR_NOT_FOUND;
 
     kern_return_t kernResult;
     io_object_t interfaceService;
     io_object_t controllerService = 0;
 
     while ((interfaceService = IOIteratorNext(primaryInterfaceIterator)))
     {
-        CFTypeRef MACAddressAsCFData   = nullptr;
-        CFTypeRef linkStatusAsCFNumber = nullptr;
-        kernResult                     = IORegistryEntryGetParentEntry(interfaceService, kIOServicePlane, &controllerService);
+        kernResult = IORegistryEntryGetParentEntry(interfaceService, kIOServicePlane, &controllerService);
+        IOObjectRelease(interfaceService);
         VerifyOrExit(KERN_SUCCESS == kernResult, err = CHIP_ERROR_INTERNAL);
 
-        linkStatusAsCFNumber = IORegistryEntryCreateCFProperty(controllerService, CFSTR(kIOLinkStatus), kCFAllocatorDefault, 0);
+        CFTypeRef linkStatusAsCFNumber =
+            IORegistryEntryCreateCFProperty(controllerService, CFSTR(kIOLinkStatus), kCFAllocatorDefault, 0);
         VerifyOrExit(linkStatusAsCFNumber != nullptr, err = CHIP_ERROR_INTERNAL);
 
         uint64_t linkStatus;
@@ -115,27 +115,21 @@ CHIP_ERROR GetMACAddressFromInterfaces(io_iterator_t primaryInterfaceIterator, u
 
         if ((linkStatus & kIONetworkLinkValid) && (linkStatus & kIONetworkLinkActive))
         {
-            MACAddressAsCFData = IORegistryEntryCreateCFProperty(controllerService, CFSTR(kIOMACAddress), kCFAllocatorDefault, 0);
+            CFTypeRef MACAddressAsCFData =
+                IORegistryEntryCreateCFProperty(controllerService, CFSTR(kIOMACAddress), kCFAllocatorDefault, 0);
             VerifyOrExit(MACAddressAsCFData != nullptr, err = CHIP_ERROR_INTERNAL);
 
             CFDataGetBytes((CFDataRef) MACAddressAsCFData, CFRangeMake(0, kIOEthernetAddressSize), buf);
             CFRelease(MACAddressAsCFData);
+            ExitNow(err = CHIP_NO_ERROR);
         }
 
-        kernResult = IOObjectRelease(controllerService);
-        VerifyOrExit(KERN_SUCCESS == kernResult, err = CHIP_ERROR_INTERNAL);
-
-        kernResult = IOObjectRelease(interfaceService);
-        VerifyOrExit(KERN_SUCCESS == kernResult, err = CHIP_ERROR_INTERNAL);
+        IOObjectRelease(controllerService);
+        controllerService = 0;
     }
 
 exit:
-    if (IOObjectGetRetainCount(interfaceService))
-    {
-        IOObjectRelease(interfaceService);
-    }
-
-    if (IOObjectGetRetainCount(controllerService))
+    if (controllerService)
     {
         IOObjectRelease(controllerService);
     }