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authorJeff Sharkey <jsharkey@android.com>2016-10-07 14:00:46 -0700
committerJessica Wagantall <jwagantall@cyngn.com>2016-11-10 12:29:00 -0800
commitb9f6359f0a771f01ccfdbfa0c7efc1622db041c5 (patch)
treeb3c187c9cc599d22e77bcb14e37ecc25c9843707
parent8901501239ce7d7f9409d9910ecd40aa78770b62 (diff)
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Enforce calling identity before clearing.stable/cm-13.0-ZNH2K
When opening a downloaded file, enforce that the caller can actually see the requested download before clearing their identity to read internal columns. However, this means that we can no longer return the "my_downloads" paths: if those Uris were shared beyond the app that requested the download, access would be denied. Instead, we need to switch to using "all_downloads" Uris so that permission grants can be issued to third-party viewer apps. Since an app requesting a download doesn't normally have permission to "all_downloads" paths, we issue narrow grants toward the owner of each download, both at device boot and when new downloads are started. CYNGNOS-3303 Bug: 30537115, 30945409 Change-Id: If944aada020878a91c363963728d0da9f6fae3ea (cherry picked from commit 7c1af8c62c8bdf6e8de5a00c1927daf9fd9c03d1)
-rw-r--r--src/com/android/providers/downloads/DownloadProvider.java31
1 files changed, 31 insertions, 0 deletions
diff --git a/src/com/android/providers/downloads/DownloadProvider.java b/src/com/android/providers/downloads/DownloadProvider.java
index d9acc78..ef64e5e 100644
--- a/src/com/android/providers/downloads/DownloadProvider.java
+++ b/src/com/android/providers/downloads/DownloadProvider.java
@@ -462,6 +462,19 @@ public final class DownloadProvider extends ContentProvider {
if (appInfo != null) {
mDefContainerUid = appInfo.uid;
}
+
+ // Grant access permissions for all known downloads to the owning apps
+ final SQLiteDatabase db = mOpenHelper.getReadableDatabase();
+ final Cursor cursor = db.query(DB_TABLE, new String[] {
+ Downloads.Impl._ID, Constants.UID }, null, null, null, null, null);
+ try {
+ while (cursor.moveToNext()) {
+ grantAllDownloadsPermission(cursor.getLong(0), cursor.getInt(1));
+ }
+ } finally {
+ cursor.close();
+ }
+
// start the DownloadService class. don't wait for the 1st download to be issued.
// saves us by getting some initialization code in DownloadService out of the way.
Context context = getContext();
@@ -687,6 +700,7 @@ public final class DownloadProvider extends ContentProvider {
}
insertRequestHeaders(db, rowID, values);
+ grantAllDownloadsPermission(rowID, Binder.getCallingUid());
notifyContentChanged(uri, match);
// Always start service to handle notifications and/or scanning
@@ -1193,6 +1207,7 @@ public final class DownloadProvider extends ContentProvider {
try {
while (cursor.moveToNext()) {
final long id = cursor.getLong(0);
+ revokeAllDownloadsPermission(id);
DownloadStorageProvider.onDownloadProviderDelete(getContext(), id);
final String path = cursor.getString(1);
@@ -1413,4 +1428,20 @@ public final class DownloadProvider extends ContentProvider {
to.put(key, defaultValue);
}
}
+
+ private void grantAllDownloadsPermission(long id, int uid) {
+ final String[] packageNames = getContext().getPackageManager().getPackagesForUid(uid);
+ if (packageNames == null || packageNames.length == 0) return;
+
+ // We only need to grant to the first package, since the
+ // platform internally tracks based on UIDs
+ final Uri uri = ContentUris.withAppendedId(Downloads.Impl.ALL_DOWNLOADS_CONTENT_URI, id);
+ getContext().grantUriPermission(packageNames[0], uri,
+ Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
+ }
+
+ private void revokeAllDownloadsPermission(long id) {
+ final Uri uri = ContentUris.withAppendedId(Downloads.Impl.ALL_DOWNLOADS_CONTENT_URI, id);
+ getContext().revokeUriPermission(uri, ~0);
+ }
}