Add sample of backup rools, and handl AEADBadTagException (#540)

* Add sample of backup rools, and handl AEADBadTagException * Typos
xamarin · Oct 9, 2018 · 74aa962 · 74aa962
1 parent 8db259f
commit 74aa962
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Showing 4 changed files with 26 additions and 2 deletions.
diff --git a/Samples/Samples.Android/Properties/AndroidManifest.xml b/Samples/Samples.Android/Properties/AndroidManifest.xml
@@ -12,5 +12,11 @@
   <uses-feature android:name="android.hardware.location" android:required="false" />
   <uses-feature android:name="android.hardware.location.gps" android:required="false" />
   <uses-feature android:name="android.hardware.location.network" android:required="false" />
-  <application android:label="@string/app_name" android:icon="@mipmap/ic_launcher" android:roundIcon="@mipmap/ic_launcher_round" android:theme="@style/MainTheme"></application>
+  <application android:label="@string/app_name" 
+               android:icon="@mipmap/ic_launcher" 
+               android:roundIcon="@mipmap/ic_launcher_round" 
+               android:theme="@style/MainTheme"
+               android:fullBackupContent="@xml/my_backup_rules">
+
+  </application>
 </manifest>
diff --git a/Samples/Samples.Android/Resources/xml/my_backup_rules.xml b/Samples/Samples.Android/Resources/xml/my_backup_rules.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<full-backup-content>
+    <include domain="sharedpref" path="."/>
+    <exclude domain="sharedpref" path="${applicationId}.xamarinessentials.xml"/>
+</full-backup-content>
diff --git a/Samples/Samples.Android/Samples.Android.csproj b/Samples/Samples.Android/Samples.Android.csproj
@@ -134,6 +134,11 @@
   <ItemGroup>
     <AndroidAsset Include="Assets\FileSystemTemplate.txt" />
   </ItemGroup>
+  <ItemGroup>
+    <AndroidResource Include="Resources\xml\my_backup_rules.xml">
+      <SubType>Designer</SubType>
+    </AndroidResource>
+  </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
   <Import Project="$(MSBuildThisFileDirectory)..\..\CodeStyles.targets" />
 </Project>
diff --git a/Xamarin.Essentials/SecureStorage/SecureStorage.android.cs b/Xamarin.Essentials/SecureStorage/SecureStorage.android.cs
@@ -26,7 +26,15 @@ static Task<string> PlatformGetAsync(string key)
             {
                 var encData = Convert.FromBase64String(encStr);
                 var ks = new AndroidKeyStore(context, Alias, AlwaysUseAsymmetricKeyStorage);
-                decryptedData = ks.Decrypt(encData);
+                try
+                {
+                    decryptedData = ks.Decrypt(encData);
+                }
+                catch (AEADBadTagException)
+                {
+                    System.Diagnostics.Debug.WriteLine($"Unable to decrypt key, {key}, which is likely due to an app uninstall. Removing old key and returning null.");
+                    PlatformRemove(key);
+                }
             }
 
             return Task.FromResult(decryptedData);