From 8ec005728d47e282d72801b4bb43c9a3ea8f717f Mon Sep 17 00:00:00 2001 From: Jeff Sharkey Date: Thu, 7 Jan 2016 14:15:59 -0700 Subject: Use resolved path for both checking and opening. This avoids a race condition where someone can change a symlink target after the security checks have passed. Bug: 26211054 Change-Id: I5842aaecc7b7d417a3b1902957b59b8a1f3c1ccb --- src/com/android/providers/downloads/DownloadProvider.java | 10 ++++++++-- src/com/android/providers/downloads/Helpers.java | 4 ---- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/src/com/android/providers/downloads/DownloadProvider.java b/src/com/android/providers/downloads/DownloadProvider.java index 94e5a997..620085fc 100644 --- a/src/com/android/providers/downloads/DownloadProvider.java +++ b/src/com/android/providers/downloads/DownloadProvider.java @@ -1260,9 +1260,15 @@ public final class DownloadProvider extends ContentProvider { throw new FileNotFoundException("No filename found."); } - final File file = new File(path); + final File file; + try { + file = new File(path).getCanonicalFile(); + } catch (IOException e) { + throw new FileNotFoundException(e.getMessage()); + } + if (!Helpers.isFilenameValid(getContext(), file)) { - throw new FileNotFoundException("Invalid file: " + file); + throw new FileNotFoundException("Invalid file path: " + file); } final int pfdMode = ParcelFileDescriptor.parseMode(mode); diff --git a/src/com/android/providers/downloads/Helpers.java b/src/com/android/providers/downloads/Helpers.java index d1cc5450..d01cbff2 100644 --- a/src/com/android/providers/downloads/Helpers.java +++ b/src/com/android/providers/downloads/Helpers.java @@ -357,8 +357,6 @@ public class Helpers { static boolean isFilenameValidInExternalPackage(Context context, File file, String packageName) { try { - file = file.getCanonicalFile(); - if (containsCanonical(buildExternalStorageAppFilesDirs(packageName), file) || containsCanonical(buildExternalStorageAppObbDirs(packageName), file) || containsCanonical(buildExternalStorageAppCacheDirs(packageName), file) || @@ -380,8 +378,6 @@ public class Helpers { */ static boolean isFilenameValid(Context context, File file, boolean allowInternal) { try { - file = file.getCanonicalFile(); - if (allowInternal) { if (containsCanonical(context.getFilesDir(), file) || containsCanonical(context.getCacheDir(), file) -- cgit v1.2.3