Merge branch 'fallback-install' into 'master'

Use AOSP Installer if permission check fails

If the old repo index is used and the permission check fails in ApkVerifier, this allows a fallback to the AOSP DefaultInstaller to show all permissions.
This has been discussed in https://gitlab.com/fdroid/fdroidclient/issues/704

Unfortunately, this shows our permission screen before download and then afterwards when the ``ApkVerifier`` fails the permission screen of the AOSP DefaultInstaller, i.e., the user sees two permission screen which she needs to acknowledge. This should only happen if an old repo format is used, thus I think this is okay. I don't know of any other solution to this problem.

See merge request !369

app/src/main/java/org/fdroid/fdroid/installer/ApkVerifier.java

@@ -51,7 +51,7 @@ class ApkVerifier {
         this.pm = context.getPackageManager();
     }
 
-    public void verifyApk() throws ApkVerificationException {
+    public void verifyApk() throws ApkVerificationException, ApkPermissionUnequalException {
         // parse downloaded apk file locally
         PackageInfo localApkInfo = pm.getPackageArchiveInfo(
                 localApkUri.getPath(), PackageManager.GET_PERMISSIONS);
@@ -78,9 +78,9 @@ class ApkVerifier {
         // Thus, containsAll() instead of equals() is used!
         // See also https://gitlab.com/fdroid/fdroidclient/issues/703
         if (!expectedPermissions.containsAll(localPermissions)) {
-            throw new ApkVerificationException(
+            throw new ApkPermissionUnequalException(
                     "Permissions of the apk file are not a true subset of the permissions listed by the repo," +
-                    " i.e., some permissions have not been shown to the user!");
+                            " i.e., some permissions have not been shown to the user!");
         }
 
         int localTargetSdkVersion = localApkInfo.applicationInfo.targetSdkVersion;
@@ -93,7 +93,6 @@ class ApkVerifier {
         } else if (localTargetSdkVersion != expectedTargetSdkVersion) {
             throw new ApkVerificationException("TargetSdkVersion of apk file is not the expected targetSdkVersion!");
         }
-
     }
 
     private HashSet<String> getLocalPermissionsSet(PackageInfo localApkInfo) {
@@ -116,4 +115,15 @@ class ApkVerifier {
         }
     }
 
+    public static class ApkPermissionUnequalException extends Exception {
+
+        ApkPermissionUnequalException(String message) {
+            super(message);
+        }
+
+        ApkPermissionUnequalException(Throwable cause) {
+            super(cause);
+        }
+    }
+
 }

app/src/main/java/org/fdroid/fdroid/installer/Installer.java

@@ -226,17 +226,35 @@ public abstract class Installer {
      * @param apk         apk object of the app that should be installed
      */
     public void installPackage(Uri localApkUri, Uri downloadUri, Apk apk) {
-        Uri sanitizedUri;
         try {
             // verify that permissions of the apk file match the ones from the apk object
             ApkVerifier apkVerifier = new ApkVerifier(context, localApkUri, apk);
             apkVerifier.verifyApk();
+        } catch (ApkVerifier.ApkVerificationException e) {
+            Log.e(TAG, e.getMessage(), e);
+            sendBroadcastInstall(downloadUri, Installer.ACTION_INSTALL_INTERRUPTED,
+                    e.getMessage());
+            return;
+        } catch (ApkVerifier.ApkPermissionUnequalException e) {
+            // if permissions of apk are not the ones listed in the repo
+            // and an unattended installer is used, a wrong permission screen
+            // has been shown, thus fallback to AOSP DefaultInstaller!
+            if (isUnattended()) {
+                Log.e(TAG, e.getMessage(), e);
+                Log.e(TAG, "Falling back to AOSP DefaultInstaller!");
+                DefaultInstaller defaultInstaller = new DefaultInstaller(context);
+                defaultInstaller.installPackageInternal(localApkUri, downloadUri, apk);
+                return;
+            }
+        }
 
+        Uri sanitizedUri;
+        try {
             // move apk file to private directory for installation and check hash
             sanitizedUri = ApkFileProvider.getSafeUri(
                     context, localApkUri, apk, supportsContentUri());
-        } catch (ApkVerifier.ApkVerificationException | IOException e) {
+        } catch (IOException e) {
-            Log.e(TAG, "ApkVerifier / ApkFileProvider failed", e);
+            Log.e(TAG, e.getMessage(), e);
             sendBroadcastInstall(downloadUri, Installer.ACTION_INSTALL_INTERRUPTED,
                     e.getMessage());
             return;