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Commit 75f984bd authored by Abhijeet Kaur's avatar Abhijeet Kaur
Browse files

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
parent e0f4a9bb

core/java/android/provider/DocumentsProvider.java

+18 −7
Original line number Diff line number Diff line
@@ -239,6 +239,10 @@ public abstract class DocumentsProvider extends ContentProvider { 
        }

    }



    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
@@ -1086,11 +1090,18 @@ public abstract class DocumentsProvider extends ContentProvider { 
        // If the URI is a tree URI performs some validation.

        enforceTreeForExtraUris(extras);



        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);
@@ -1100,7 +1111,7 @@ public abstract class DocumentsProvider extends ContentProvider { 
            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);
@@ -1113,7 +1124,7 @@ public abstract class DocumentsProvider extends ContentProvider { 
            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);
@@ -1180,7 +1191,7 @@ public abstract class DocumentsProvider extends ContentProvider { 
            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(),
@@ -1204,9 +1215,9 @@ public abstract class DocumentsProvider extends ContentProvider { 
            }



        } 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(),
@@ -1232,7 +1243,7 @@ public abstract class DocumentsProvider extends ContentProvider { 
            }



        } 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(),