Fix path traversal vulnerabilities in MediaProvider
Canonicalize filepath provided by the caller when hanling SCAN_FILE_CALL
method call in MediaProvider.
Additionally, make sure to check access permission in SCAN_FILE_CALL
(using enforceCallingPermissionInternal()).
Preemptively canonicalize Files provided as an arguments to the public
API methods in ModernMediaScanner (scanFile(), scanDirectory() and
onDirectoryDirty()) to prevent path traversal attacks.
Bug: 262244882
Test: atest MediaProviderTests
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:5d2808f30c9dbe35ddbefeda4845328557569a93)
Merged-In: I61e77d69ae857984b819fa0ea27bec5c26a34842
Change-Id: I61e77d69ae857984b819fa0ea27bec5c26a34842
Change-Id: I54b6e16d2cc9ec5067d1102226feaf8a886d27dc
diff --git a/src/com/android/providers/media/MediaProvider.java b/src/com/android/providers/media/MediaProvider.java
index 5bc77d0..035daa1 100644
--- a/src/com/android/providers/media/MediaProvider.java
+++ b/src/com/android/providers/media/MediaProvider.java
@@ -4550,31 +4550,44 @@
BackgroundThread.waitForIdle();
return null;
}
- case MediaStore.SCAN_FILE_CALL:
+ case MediaStore.SCAN_FILE_CALL: {
+ final LocalCallingIdentity token = clearLocalCallingIdentity();
+ final CallingIdentity providerToken = clearCallingIdentity();
+
+ final String filePath = arg;
+ final Uri uri;
+ try {
+ File file;
+ try {
+ file = FileUtils.getCanonicalFile(filePath);
+ } catch (IOException e) {
+ file = null;
+ }
+
+ uri = file != null ? scanFile(file, REASON_DEMAND) : null;
+ } finally {
+ restoreCallingIdentity(providerToken);
+ restoreLocalCallingIdentity(token);
+ }
+
+ final Bundle res = new Bundle();
+ res.putParcelable(Intent.EXTRA_STREAM, uri);
+ return res;
+ }
case MediaStore.SCAN_VOLUME_CALL: {
final LocalCallingIdentity token = clearLocalCallingIdentity();
final CallingIdentity providerToken = clearCallingIdentity();
+
+ final String volumeName = arg;
try {
- final Bundle res = new Bundle();
- switch (method) {
- case MediaStore.SCAN_FILE_CALL: {
- final File file = new File(arg);
- res.putParcelable(Intent.EXTRA_STREAM, scanFile(file, REASON_DEMAND));
- break;
- }
- case MediaStore.SCAN_VOLUME_CALL: {
- final String volumeName = arg;
- MediaService.onScanVolume(getContext(), volumeName, REASON_DEMAND);
- break;
- }
- }
- return res;
+ MediaService.onScanVolume(getContext(), volumeName, REASON_DEMAND);
} catch (IOException e) {
throw new RuntimeException(e);
} finally {
restoreCallingIdentity(providerToken);
restoreLocalCallingIdentity(token);
}
+ return Bundle.EMPTY;
}
case MediaStore.GET_VERSION_CALL: {
final String volumeName = extras.getString(Intent.EXTRA_TEXT);
diff --git a/src/com/android/providers/media/scan/ModernMediaScanner.java b/src/com/android/providers/media/scan/ModernMediaScanner.java
index 58e63cd..88cf60b 100644
--- a/src/com/android/providers/media/scan/ModernMediaScanner.java
+++ b/src/com/android/providers/media/scan/ModernMediaScanner.java
@@ -47,6 +47,8 @@
import static android.text.format.DateUtils.HOUR_IN_MILLIS;
import static android.text.format.DateUtils.MINUTE_IN_MILLIS;
+import static java.util.Objects.requireNonNull;
+
import android.content.ContentProviderClient;
import android.content.ContentProviderOperation;
import android.content.ContentProviderResult;
@@ -221,7 +223,15 @@
}
@Override
- public void scanDirectory(File file, int reason) {
+ public void scanDirectory(@NonNull File file, int reason) {
+ requireNonNull(file);
+ try {
+ file = file.getCanonicalFile();
+ } catch (IOException e) {
+ Log.e(TAG, "Couldn't canonicalize directory to scan" + file, e);
+ return;
+ }
+
try (Scan scan = new Scan(file, reason, /*ownerPackage*/ null)) {
scan.run();
} catch (OperationCanceledException ignored) {
@@ -229,12 +239,21 @@
}
@Override
- public Uri scanFile(File file, int reason) {
+ @Nullable
+ public Uri scanFile(@NonNull File file, int reason) {
return scanFile(file, reason, /*ownerPackage*/ null);
}
@Override
public Uri scanFile(File file, int reason, @Nullable String ownerPackage) {
+ requireNonNull(file);
+ try {
+ file = file.getCanonicalFile();
+ } catch (IOException e) {
+ Log.e(TAG, "Couldn't canonicalize file to scan" + file, e);
+ return null;
+ }
+
try (Scan scan = new Scan(file, reason, ownerPackage)) {
scan.run();
return scan.getFirstResult();
diff --git a/src/com/android/providers/media/util/FileUtils.java b/src/com/android/providers/media/util/FileUtils.java
index 64aaa41..29245d3 100644
--- a/src/com/android/providers/media/util/FileUtils.java
+++ b/src/com/android/providers/media/util/FileUtils.java
@@ -957,18 +957,25 @@
}
public static @Nullable String extractRelativePath(@Nullable String data) {
- data = getCanonicalPath(data);
if (data == null) return null;
- final Matcher matcher = PATTERN_RELATIVE_PATH.matcher(data);
+ final String path;
+ try {
+ path = getCanonicalPath(data);
+ } catch (IOException e) {
+ Log.d(TAG, "Unable to get canonical path from invalid data path: " + data, e);
+ return null;
+ }
+
+ final Matcher matcher = PATTERN_RELATIVE_PATH.matcher(path);
if (matcher.find()) {
- final int lastSlash = data.lastIndexOf('/');
+ final int lastSlash = path.lastIndexOf('/');
if (lastSlash == -1 || lastSlash < matcher.end()) {
// This is a file in the top-level directory, so relative path is "/"
// which is different than null, which means unknown path
return "/";
} else {
- return data.substring(matcher.end(), lastSlash + 1);
+ return path.substring(matcher.end(), lastSlash + 1);
}
} else {
return null;
@@ -1342,15 +1349,29 @@
return status;
}
- @Nullable
- private static String getCanonicalPath(@Nullable String path) {
- if (path == null) return null;
+ /**
+ * Returns the canonical {@link File} for the provided abstract pathname.
+ *
+ * @return The canonical pathname string denoting the same file or directory as this abstract
+ * pathname
+ * @see File#getCanonicalFile()
+ */
+ @NonNull
+ public static File getCanonicalFile(@NonNull String path) throws IOException {
+ Objects.requireNonNull(path);
+ return new File(path).getCanonicalFile();
+ }
- try {
- return new File(path).getCanonicalPath();
- } catch (IOException e) {
- Log.d(TAG, "Unable to get canonical path from invalid data path: " + path, e);
- return null;
- }
+ /**
+ * Returns the canonical pathname string of the provided abstract pathname.
+ *
+ * @return The canonical pathname string denoting the same file or directory as this abstract
+ * pathname.
+ * @see File#getCanonicalPath()
+ */
+ @NonNull
+ public static String getCanonicalPath(@NonNull String path) throws IOException {
+ Objects.requireNonNull(path);
+ return new File(path).getCanonicalPath();
}
}