RESTRICT AUTOMERGE

Enable stricter SQLiteQueryBuilder options.

Malicious callers can leak side-channel information by using
subqueries in any untrusted inputs where SQLite allows "expr" values.

This change starts using setStrictColumns() and setStrictGrammar()
on SQLiteQueryBuilder to block this class of attacks.  This means we
now need to define the projection mapping of valid columns, which
consists of both the columns defined in the public API and columns
read internally by DownloadInfo.Reader.

We're okay growing sAppReadableColumnsSet like this, since we're
relying on our trusted WHERE clause to filter away any rows that
don't belong to the calling UID.

Remove the legacy Lexer code, since we're now internally relying on
the robust and well-tested SQLiteTokenizer logic.

Bug: 135270103
Bug: 135269143
Test: atest DownloadProviderTests
Test: atest CtsAppTestCases:android.app.cts.DownloadManagerTest
Change-Id: Iec1e8ce18dc4a9564318e0473d9d3863c8c2988a
(cherry picked from commit 13f49c42599dc2ea0be376be34275aefcb70d398)

1 files changed, 22 insertions, 20 deletions

diff --git a/core/java/android/app/DownloadManager.java b/core/java/android/app/DownloadManager.java
index 1166cb57cca..77a777024a2 100644
--- a/core/java/android/app/DownloadManager.java
+++ b/core/java/android/app/DownloadManager.java
@@ -132,6 +132,9 @@ public class DownloadManager {
      */
     public final static String COLUMN_STATUS = Downloads.Impl.COLUMN_STATUS;
 
+    /** {@hide} */
+    public static final String COLUMN_FILE_NAME_HINT = Downloads.Impl.COLUMN_FILE_NAME_HINT;
+
     /**
      * Provides more detail on the status of the download.  Its meaning depends on the value of
      * {@link #COLUMN_STATUS}.
@@ -173,6 +176,9 @@ public class DownloadManager {
     @TestApi
     public static final String COLUMN_MEDIASTORE_URI = Downloads.Impl.COLUMN_MEDIASTORE_URI;
 
+    /** {@hide} */
+    public static final String COLUMN_DESTINATION = Downloads.Impl.COLUMN_DESTINATION;
+
     /**
      * @hide
      */
@@ -340,26 +346,22 @@ public class DownloadManager {
      */
     @UnsupportedAppUsage
     public static final String[] UNDERLYING_COLUMNS = new String[] {
-        Downloads.Impl._ID,
-        Downloads.Impl._DATA + " AS " + COLUMN_LOCAL_FILENAME,
-        Downloads.Impl.COLUMN_MEDIAPROVIDER_URI,
-        Downloads.Impl.COLUMN_DESTINATION,
-        Downloads.Impl.COLUMN_TITLE,
-        Downloads.Impl.COLUMN_DESCRIPTION,
-        Downloads.Impl.COLUMN_URI,
-        Downloads.Impl.COLUMN_STATUS,
-        Downloads.Impl.COLUMN_FILE_NAME_HINT,
-        Downloads.Impl.COLUMN_MIME_TYPE + " AS " + COLUMN_MEDIA_TYPE,
-        Downloads.Impl.COLUMN_TOTAL_BYTES + " AS " + COLUMN_TOTAL_SIZE_BYTES,
-        Downloads.Impl.COLUMN_LAST_MODIFICATION + " AS " + COLUMN_LAST_MODIFIED_TIMESTAMP,
-        Downloads.Impl.COLUMN_CURRENT_BYTES + " AS " + COLUMN_BYTES_DOWNLOADED_SO_FAR,
-        Downloads.Impl.COLUMN_ALLOW_WRITE,
-        /* add the following 'computed' columns to the cursor.
-         * they are not 'returned' by the database, but their inclusion
-         * eliminates need to have lot of methods in CursorTranslator
-         */
-        "'placeholder' AS " + COLUMN_LOCAL_URI,
-        "'placeholder' AS " + COLUMN_REASON
+        DownloadManager.COLUMN_ID,
+        DownloadManager.COLUMN_LOCAL_FILENAME,
+        DownloadManager.COLUMN_MEDIAPROVIDER_URI,
+        DownloadManager.COLUMN_DESTINATION,
+        DownloadManager.COLUMN_TITLE,
+        DownloadManager.COLUMN_DESCRIPTION,
+        DownloadManager.COLUMN_URI,
+        DownloadManager.COLUMN_STATUS,
+        DownloadManager.COLUMN_FILE_NAME_HINT,
+        DownloadManager.COLUMN_MEDIA_TYPE,
+        DownloadManager.COLUMN_TOTAL_SIZE_BYTES,
+        DownloadManager.COLUMN_LAST_MODIFIED_TIMESTAMP,
+        DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR,
+        DownloadManager.COLUMN_ALLOW_WRITE,
+        DownloadManager.COLUMN_LOCAL_URI,
+        DownloadManager.COLUMN_REASON
     };
 
     /**