ioctl(2) and ftruncate(2) operations on files opened with O_PATH
should always return EBADF, independent of the
LANDLOCK_ACCESS_FS_TRUNCATE and LANDLOCK_ACCESS_FS_IOCTL_DEV access
rights in that file hierarchy.
Suggested-by: Mickaël Salaün <mic@xxxxxxxxxxx>
Signed-off-by: Günther Noack <gnoack@xxxxxxxxxx>
---
tools/testing/selftests/landlock/fs_test.c | 40 ++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
index 32a77757462b..dde4673e2df4 100644
--- a/tools/testing/selftests/landlock/fs_test.c
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -3893,6 +3893,46 @@ static int test_fionread_ioctl(int fd)
return 0;
}
+TEST_F_FORK(layout1, o_path_ftruncate_and_ioctl)
+{
+ const struct landlock_ruleset_attr attr = {
+ .handled_access_fs = ACCESS_ALL,
+ };
+ int ruleset_fd, fd;
+
+ /*
+ * Checks that for files opened with O_PATH, both ioctl(2) and
+ * ftruncate(2) yield EBADF, as it is documented in open(2) for the
+ * O_PATH flag.
+ */
+ fd = open(dir_s1d1, O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, fd);
+
+ EXPECT_EQ(EBADF, test_ftruncate(fd));
+ EXPECT_EQ(EBADF, test_fs_ioc_getflags_ioctl(fd));
+
+ ASSERT_EQ(0, close(fd));
+
+ /* Enables Landlock. */
+ ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * Checks that after enabling Landlock,
+ * - the file can still be opened with O_PATH
+ * - both ioctl and truncate still yield EBADF (not EACCES).
+ */
+ fd = open(dir_s1d1, O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, fd);
+
+ EXPECT_EQ(EBADF, test_ftruncate(fd));
+ EXPECT_EQ(EBADF, test_fs_ioc_getflags_ioctl(fd));
+
+ ASSERT_EQ(0, close(fd));
+}
+
/* clang-format off */
FIXTURE(ioctl) {};
--
2.44.0.396.g6e790dbe36-goog
