[CDM] Remove mac address while storing last removed association.

Sample dump:
1740519388424 shell Association{mId=5, mUserId=0, mPackageName='testapp', mDeviceMacAddress=null, mDisplayName='', mDeviceProfile='null', mSelfManaged=false, mAssociatedDevice=null, mNotifyOnDeviceNearby=false, mRevoked=false, mPending=false, mTimeApprovedMs=Tue Feb 25 13:36:20 PST 2025, mLastTimeConnectedMs=None, mSystemDataSyncFlags=0, mDeviceId='null}

Fix: 397461312
Flag: EXEMPT bugfix
Test: manual
Change-Id: I1ecd8ad8d6579191197fae36a25048e034e725a7

1 files changed, 12 insertions, 2 deletions

diff --git a/services/companion/java/com/android/server/companion/association/AssociationDiskStore.java b/services/companion/java/com/android/server/companion/association/AssociationDiskStore.java
index ce7dcd0fa1d4..03107563ec22 100644
--- a/services/companion/java/com/android/server/companion/association/AssociationDiskStore.java
+++ b/services/companion/java/com/android/server/companion/association/AssociationDiskStore.java
@@ -299,14 +299,24 @@ public final class AssociationDiskStore {
     public void writeLastRemovedAssociation(AssociationInfo association, String reason) {
         Slog.i(TAG, "Writing last removed association=" + association.getId() + " to disk...");
 
+        // Remove indirect identifier i.e. Mac Address
+        AssociationInfo.Builder builder = new AssociationInfo.Builder(association)
+                .setDeviceMacAddress(null);
+        // Set a placeholder display name if it's null because Mac Address and display name can't be
+        // both null.
+        if (association.getDisplayName() == null) {
+            builder.setDisplayName("");
+        }
+        AssociationInfo redactedAssociation = builder.build();
+
         final AtomicFile file = createStorageFileForUser(
-                association.getUserId(), FILE_NAME_LAST_REMOVED_ASSOCIATION);
+                redactedAssociation.getUserId(), FILE_NAME_LAST_REMOVED_ASSOCIATION);
         writeToFileSafely(file, out -> {
             out.write(String.valueOf(System.currentTimeMillis()).getBytes());
             out.write(' ');
             out.write(reason.getBytes());
             out.write(' ');
-            out.write(association.toString().getBytes());
+            out.write(redactedAssociation.toString().getBytes());
         });
     }