[PATCH v6 20/26] selftests/landlock: Extend tests for landlock_restrict_self(2)'s flags

[Mickaël Salaün]

Add the base_test's restrict_self_fd_flags tests to align with previous
restrict_self_fd tests but with the new
LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF flag.

Add the restrict_self_flags tests to check that
LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF,
LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON, and
LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF are valid but not the next
bit.  Some checks are similar to restrict_self_checks_ordering's ones.

Cc: Günther Noack <gnoack at google.com>
Cc: Paul Moore <paul at paul-moore.com>
Signed-off-by: Mickaël Salaün <mic at digikod.net>
Link: https://lore.kernel.org/r/20250308184422.2159360-21-mic@digikod.net
---

Changes since v5:
- Rename restrict flags.
- Update LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF test to pass with -1
  as ruleset FD, and flag ordering.
- Add restrict_self_fd_flags tests.

Changes since v4:
- Update with LANDLOCK_RESTRICT_SELF_QUIET_SUBDOMAINS, and
  LANDLOCK_RESTRICT_SELF_LOG_CROSS_EXEC.

Changes since v3:
- Use a last_flag variable.

Changes since v2:
- New patch.
---
 tools/testing/selftests/landlock/base_test.c | 71 ++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c
index 9059045ae8b6..ab00afe1fc25 100644
--- a/tools/testing/selftests/landlock/base_test.c
+++ b/tools/testing/selftests/landlock/base_test.c
@@ -244,6 +244,77 @@ TEST(restrict_self_fd)
 	EXPECT_EQ(EBADFD, errno);
 }
 
+TEST(restrict_self_fd_flags)
+{
+	int fd;
+
+	fd = open("/dev/null", O_RDONLY | O_CLOEXEC);
+	ASSERT_LE(0, fd);
+
+	/*
+	 * LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF accepts -1 but not any file
+	 * descriptor.
+	 */
+	EXPECT_EQ(-1, landlock_restrict_self(
+			      fd, LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF));
+	EXPECT_EQ(EBADFD, errno);
+}
+
+TEST(restrict_self_flags)
+{
+	const __u32 last_flag = LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF;
+
+	/* Tests invalid flag combinations. */
+
+	EXPECT_EQ(-1, landlock_restrict_self(-1, last_flag << 1));
+	EXPECT_EQ(EINVAL, errno);
+
+	EXPECT_EQ(-1, landlock_restrict_self(-1, -1));
+	EXPECT_EQ(EINVAL, errno);
+
+	/* Tests valid flag combinations. */
+
+	EXPECT_EQ(-1, landlock_restrict_self(-1, 0));
+	EXPECT_EQ(EBADF, errno);
+
+	EXPECT_EQ(-1, landlock_restrict_self(
+			      -1, LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF));
+	EXPECT_EQ(EBADF, errno);
+
+	EXPECT_EQ(-1,
+		  landlock_restrict_self(
+			  -1,
+			  LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF |
+				  LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF));
+	EXPECT_EQ(EBADF, errno);
+
+	EXPECT_EQ(-1,
+		  landlock_restrict_self(
+			  -1,
+			  LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON |
+				  LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF));
+	EXPECT_EQ(EBADF, errno);
+
+	EXPECT_EQ(-1, landlock_restrict_self(
+			      -1, LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON));
+	EXPECT_EQ(EBADF, errno);
+
+	EXPECT_EQ(-1,
+		  landlock_restrict_self(
+			  -1, LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF |
+				      LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON));
+	EXPECT_EQ(EBADF, errno);
+
+	/* Tests with an invalid ruleset_fd. */
+
+	EXPECT_EQ(-1, landlock_restrict_self(
+			      -2, LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF));
+	EXPECT_EQ(EBADF, errno);
+
+	EXPECT_EQ(0, landlock_restrict_self(
+			     -1, LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF));
+}
+
 TEST(ruleset_fd_io)
 {
 	struct landlock_ruleset_attr ruleset_attr = {
-- 
2.48.1