Fix CTS tests for RNG devices.
SELinux-based Mandatory Access Control (MAC) is now specifying access
rules for /dev/random, /dev/random and /dev/hw_random. As a result,
CTS tests that rely solely on Discretionary Access Control (DAC)
(e.g., based on stat) are out of date. In particular, the test that
invoked stat on /dev/hw_random and inspected the file's mode is
breaking because stat is denied by SELinux rules
(see https://android-review.googlesource.com/#/c/67014/).
The fix is to test for access by actually opening the above RNG device
files. DAC/stat-based checks have been left in place to augment the
tests until detailed SELinux-based tests are in place.
Bug: 17259230
Change-Id: I161bd7bc8056c53e5162279af1ce91ea23504075
diff --git a/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java b/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
index 61998e7..5faaef1 100755
--- a/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
+++ b/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
@@ -31,7 +31,9 @@
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
+import java.io.InputStream;
import java.io.IOException;
+import java.io.OutputStream;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executors;
@@ -815,19 +817,29 @@
}
public void testDevRandomWorldReadableAndWritable() throws Exception {
+ File f = new File("/dev/random");
+
+ assertTrue(f + " cannot be opened for reading", canOpenForReading(f));
+ assertTrue(f + " cannot be opened for writing", canOpenForWriting(f));
+
FileUtils.FileStatus status = new FileUtils.FileStatus();
- assertTrue(FileUtils.getFileStatus("/dev/random", status, false));
+ assertTrue(FileUtils.getFileStatus(f.getPath(), status, false));
assertTrue(
- "/dev/random not world-readable/writable. Actual mode: 0"
+ f + " not world-readable/writable. Actual mode: 0"
+ Integer.toString(status.mode, 8),
(status.mode & 0666) == 0666);
}
public void testDevUrandomWorldReadableAndWritable() throws Exception {
+ File f = new File("/dev/urandom");
+
+ assertTrue(f + " cannot be opened for reading", canOpenForReading(f));
+ assertTrue(f + " cannot be opened for writing", canOpenForWriting(f));
+
FileUtils.FileStatus status = new FileUtils.FileStatus();
- assertTrue(FileUtils.getFileStatus("/dev/urandom", status, false));
+ assertTrue(FileUtils.getFileStatus(f.getPath(), status, false));
assertTrue(
- "/dev/urandom not world-readable/writable. Actual mode: 0"
+ f + " not world-readable/writable. Actual mode: 0"
+ Integer.toString(status.mode, 8),
(status.mode & 0666) == 0666);
}
@@ -839,15 +851,28 @@
return;
}
- FileUtils.FileStatus status = new FileUtils.FileStatus();
- assertTrue(FileUtils.getFileStatus(f.getCanonicalPath(), status, false));
- assertTrue(
- f + " has wrong file mode: 0"
- + Integer.toOctalString(status.mode),
- (status.mode & 0777) == 0440);
+ assertFalse(f + " can be opened for reading", canOpenForReading(f));
+ assertFalse(f + " can be opened for writing", canOpenForWriting(f));
- assertFileOwnedBy(f, "root");
- assertFileOwnedByGroup(f, "system");
+ FileUtils.FileStatus status = new FileUtils.FileStatus();
+ assertFalse("stat permitted on " + f,
+ FileUtils.getFileStatus(f.getPath(), status, false));
+ }
+
+ private static boolean canOpenForReading(File f) {
+ try (InputStream in = new FileInputStream(f)) {
+ return true;
+ } catch (IOException expected) {
+ return false;
+ }
+ }
+
+ private static boolean canOpenForWriting(File f) {
+ try (OutputStream out = new FileOutputStream(f)) {
+ return true;
+ } catch (IOException expected) {
+ return false;
+ }
}
public void testFileHasOnlyCapsThrowsOnInvalidCaps() throws Exception {
