[nfc] Fix string injection in default payment app selector

Backwards compatible port of ag/35084316

Bug: 429417453
Test: Manually by installing settings app
Flag: EXEMPT security fix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:6c723a4361950e8e43cc5caf67455bd2f00911d1)
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:b04265c1b84104884654d4957c5fb3a8ac84bc00
Merged-In: I670774a5efa6f543a5e1e06798a5d6ebb1c48c1d
Change-Id: I670774a5efa6f543a5e1e06798a5d6ebb1c48c1d

src/com/android/settings/nfc/DefaultPaymentSettings.java

@@ -17,7 +17,6 @@
 package com.android.settings.nfc;
 
 import android.app.settings.SettingsEnums;
-import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.graphics.drawable.Drawable;
@@ -45,6 +44,9 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 /**
  * DefaultPaymentSettings handles the NFC default payment app selection.
@@ -53,7 +55,7 @@ public class DefaultPaymentSettings extends DefaultAppPickerFragment {
     public static final String TAG = "DefaultPaymentSettings";
 
     private PaymentBackend mPaymentBackend;
-    private List<PaymentAppInfo> mAppInfos;
+    private Map<String, PaymentAppInfo> mAppInfos;
     private FooterPreference mFooterPreference;
 
     @Override
@@ -67,22 +69,19 @@ public class DefaultPaymentSettings extends DefaultAppPickerFragment {
     }
 
     @Override
+    @SuppressWarnings("NullAway")
     protected String getDefaultKey() {
         PaymentAppInfo defaultAppInfo = mPaymentBackend.getDefaultApp();
-        if (defaultAppInfo != null) {
-            return defaultAppInfo.componentName.flattenToString() + " "
-                    + defaultAppInfo.userHandle.getIdentifier();
-        }
-        return null;
+        if (defaultAppInfo == null) return null;
+        return defaultAppInfo.getKey();
     }
 
     @Override
     protected boolean setDefaultKey(String key) {
-        String[] keys = key.split(" ");
-        if (keys.length >= 2) {
-            mPaymentBackend.setDefaultPaymentApp(ComponentName.unflattenFromString(keys[0]),
-                    Integer.parseInt(keys[1]));
-        }
+        PaymentAppInfo appInfo = mAppInfos.get(key);
+        if (appInfo == null) return true;
+        mPaymentBackend.setDefaultPaymentApp(
+                appInfo.componentName, appInfo.userHandle.getIdentifier());
         return true;
     }
 
@@ -90,7 +89,9 @@ public class DefaultPaymentSettings extends DefaultAppPickerFragment {
     public void onAttach(Context context) {
         super.onAttach(context);
         mPaymentBackend = new PaymentBackend(getActivity());
-        mAppInfos = mPaymentBackend.getPaymentAppInfos();
+        mAppInfos = mPaymentBackend.getPaymentAppInfos()
+                .stream()
+                .collect(Collectors.toMap(PaymentAppInfo::getKey, Function.identity()));
     }
 
     @Override
@@ -147,7 +148,7 @@ public class DefaultPaymentSettings extends DefaultAppPickerFragment {
     @Override
     protected List<? extends CandidateInfo> getCandidates() {
         final List<NfcPaymentCandidateInfo> candidates = new ArrayList<>();
-        for (PaymentAppInfo appInfo: mAppInfos) {
+        for (PaymentAppInfo appInfo: mAppInfos.values()) {
             UserManager um = getContext().createContextAsUser(
                     appInfo.userHandle, /*flags=*/0).getSystemService(UserManager.class);
             boolean isManagedProfile = um.isManagedProfile(appInfo.userHandle.getIdentifier());

src/com/android/settings/nfc/PaymentBackend.java

@@ -36,6 +36,7 @@ import com.android.internal.content.PackageMonitor;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
 public class PaymentBackend {
     public static final String TAG = "Settings.PaymentBackend";
@@ -52,6 +53,24 @@ public class PaymentBackend {
         public ComponentName settingsComponent;
         public UserHandle userHandle;
         public Drawable icon;
+
+        public String getKey() {
+            return Integer.toString(hashCode());
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(componentName, userHandle);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (o == this) return true;
+            if (!(o instanceof PaymentAppInfo)) return false;
+            PaymentAppInfo appInfo = (PaymentAppInfo) o;
+            return componentName.equals(appInfo.componentName)
+                    && userHandle.equals(appInfo.userHandle);
+        }
     }
 
     /**