commit 22914354906efbbe0e0fba96f998ca0066a664c3
author Abhijeet Kaur <abkaur@google.com> Thu Aug 13 12:21:15 2020 +0100
committer android-build-team Robot <android-build-team-robot@google.com> Thu Nov 12 18:33:49 2020 +0000
tree 556037b9f5863007563b626378dd9e269a6a23ee
parent e80edc571d42e100102fadd31738efbc18ef3142

Validate user-supplied URIs in DocumentsProvider calls

Some URIs are used without validating their authorities which can lead
to exploitation by malicious apps.

Bug: 157294893
Test: Manual using test app in b/157294893
Change-Id: I799509ed5ff7e69140e84d796fe7f96d9dbfd32f
Merged-In: I799509ed5ff7e69140e84d796fe7f96d9dbfd32f
(cherry picked from commit 75f984bd32a3ee8115d5cea09ab1bd237537ab54)
(cherry picked from commit e4bb1d7b6cd538acf423c7d8864dd26819fe8757)

core/java/android/provider/DocumentsProvider.java

diff --git a/core/java/android/provider/DocumentsProvider.java b/core/java/android/provider/DocumentsProvider.java
index 327bca2..91b591c 100644
--- a/core/java/android/provider/DocumentsProvider.java
+++ b/core/java/android/provider/DocumentsProvider.java
@@ -232,6 +232,10 @@
         }
     }
 
+    private Uri validateIncomingNullableUri(@Nullable Uri uri) {
+        return uri == null ? null : validateIncomingUri(uri);
+    }
+
     /**
      * Create a new document and return its newly generated
      * {@link Document#COLUMN_DOCUMENT_ID}. You must allocate a new
@@ -1076,11 +1080,18 @@
         final Context context = getContext();
         final Bundle out = new Bundle();
 
+        final Uri extraUri = validateIncomingNullableUri(
+                extras.getParcelable(DocumentsContract.EXTRA_URI));
+        final Uri extraTargetUri = validateIncomingNullableUri(
+                extras.getParcelable(DocumentsContract.EXTRA_TARGET_URI));
+        final Uri extraParentUri = validateIncomingNullableUri(
+                extras.getParcelable(DocumentsContract.EXTRA_PARENT_URI));
+
         if (METHOD_EJECT_ROOT.equals(method)) {
             // Given that certain system apps can hold MOUNT_UNMOUNT permission, but only apps
             // signed with platform signature can hold MANAGE_DOCUMENTS, we are going to check for
             // MANAGE_DOCUMENTS or associated URI permission here instead
-            final Uri rootUri = extras.getParcelable(DocumentsContract.EXTRA_URI);
+            final Uri rootUri = extraUri;
             enforceWritePermissionInner(rootUri, getCallingPackage(), getCallingAttributionTag(),
                     null);
 
@@ -1090,7 +1101,7 @@
             return out;
         }
 
-        final Uri documentUri = extras.getParcelable(DocumentsContract.EXTRA_URI);
+        final Uri documentUri = extraUri;
         final String authority = documentUri.getAuthority();
         final String documentId = DocumentsContract.getDocumentId(documentUri);
 
@@ -1106,7 +1117,7 @@
             enforceReadPermissionInner(documentUri, getCallingPackage(),
                     getCallingAttributionTag(), null);
 
-            final Uri childUri = extras.getParcelable(DocumentsContract.EXTRA_TARGET_URI);
+            final Uri childUri = extraTargetUri;
             final String childAuthority = childUri.getAuthority();
             final String childId = DocumentsContract.getDocumentId(childUri);
 
@@ -1173,7 +1184,7 @@
             revokeDocumentPermission(documentId);
 
         } else if (METHOD_COPY_DOCUMENT.equals(method)) {
-            final Uri targetUri = extras.getParcelable(DocumentsContract.EXTRA_TARGET_URI);
+            final Uri targetUri = extraTargetUri;
             final String targetId = DocumentsContract.getDocumentId(targetUri);
 
             enforceReadPermissionInner(documentUri, getCallingPackage(),
@@ -1197,9 +1208,9 @@
             }
 
         } else if (METHOD_MOVE_DOCUMENT.equals(method)) {
-            final Uri parentSourceUri = extras.getParcelable(DocumentsContract.EXTRA_PARENT_URI);
+            final Uri parentSourceUri = extraParentUri;
             final String parentSourceId = DocumentsContract.getDocumentId(parentSourceUri);
-            final Uri targetUri = extras.getParcelable(DocumentsContract.EXTRA_TARGET_URI);
+            final Uri targetUri = extraTargetUri;
             final String targetId = DocumentsContract.getDocumentId(targetUri);
 
             enforceWritePermissionInner(documentUri, getCallingPackage(),
@@ -1225,7 +1236,7 @@
             }
 
         } else if (METHOD_REMOVE_DOCUMENT.equals(method)) {
-            final Uri parentSourceUri = extras.getParcelable(DocumentsContract.EXTRA_PARENT_URI);
+            final Uri parentSourceUri = extraParentUri;
             final String parentSourceId = DocumentsContract.getDocumentId(parentSourceUri);
 
             enforceReadPermissionInner(parentSourceUri, getCallingPackage(),