diff options
| -rw-r--r-- | src/com/android/providers/telephony/MmsProvider.java | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/src/com/android/providers/telephony/MmsProvider.java b/src/com/android/providers/telephony/MmsProvider.java index b095e66..4242158 100644 --- a/src/com/android/providers/telephony/MmsProvider.java +++ b/src/com/android/providers/telephony/MmsProvider.java @@ -16,6 +16,7 @@ package com.android.providers.telephony; +import android.annotation.NonNull; import android.app.AppOpsManager; import android.content.ContentProvider; import android.content.ContentValues; @@ -276,7 +277,11 @@ public class MmsProvider extends ContentProvider { @Override public Uri insert(Uri uri, ContentValues values) { - // Don't let anyone insert anything with the _data column + // The _data column is filled internally in MmsProvider, so this check is just to avoid + // it from being inadvertently set. This is not supposed to be a protection against + // malicious attack, since sql injection could still be attempted to bypass the check. On + // the other hand, the MmsProvider does verify that the _data column has an allowed value + // before opening any uri/files. if (values != null && values.containsKey(Part._DATA)) { return null; } @@ -727,9 +732,12 @@ public class MmsProvider extends ContentProvider { } @Override - public int update(Uri uri, ContentValues values, - String selection, String[] selectionArgs) { - // Don't let anyone update the _data column + public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { + // The _data column is filled internally in MmsProvider, so this check is just to avoid + // it from being inadvertently set. This is not supposed to be a protection against + // malicious attack, since sql injection could still be attempted to bypass the check. On + // the other hand, the MmsProvider does verify that the _data column has an allowed value + // before opening any uri/files. if (values != null && values.containsKey(Part._DATA)) { return 0; } @@ -835,7 +843,12 @@ public class MmsProvider extends ContentProvider { return null; } - // Verify that the _data path points to mms data + return safeOpenFileHelper(uri, mode); + } + + @NonNull + private ParcelFileDescriptor safeOpenFileHelper( + @NonNull Uri uri, @NonNull String mode) throws FileNotFoundException { Cursor c = query(uri, new String[]{"_data"}, null, null, null); int count = (c != null) ? c.getCount() : 0; if (count != 1) { @@ -856,10 +869,16 @@ public class MmsProvider extends ContentProvider { c.close(); if (path == null) { - return null; + throw new FileNotFoundException("Column _data not found."); } + + File filePath = new File(path); try { - File filePath = new File(path); + // The MmsProvider shouldn't open a file that isn't MMS data, so we verify that the + // _data path actually points to MMS data. That safeguards ourselves from callers who + // inserted or updated a URI (more specifically the _data column) with disallowed paths. + // TODO(afurtado): provide a more robust mechanism to avoid disallowed _data paths to + // be inserted/updated in the first place, including via SQL injection. if (!filePath.getCanonicalPath() .startsWith(getContext().getApplicationInfo().dataDir + "/app_parts/")) { return null; @@ -868,7 +887,8 @@ public class MmsProvider extends ContentProvider { return null; } - return openFileHelper(uri, mode); + int modeBits = ParcelFileDescriptor.parseMode(mode); + return ParcelFileDescriptor.open(filePath, modeBits); } private void filterUnsupportedKeys(ContentValues values) { |