[RFC PATCH v19 4/5] selftests/landlock: Add tests for execveat + AT_CHECK

Mickaël Salaün
2024-07-04T19:02:14Z

Extend layout1.execute with the new AT_CHECK flag. The semantic with
AT_CHECK is the same as with a simple execve(2),
LANDLOCK_ACCESS_FS_EXECUTE is enforced the same way.

Cc: Günther Noack <gnoack@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20240704190137.696169-5-mic@digikod.net
---
tools/testing/selftests/landlock/fs_test.c | 26 ++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
index 7d063c652be1..85ef36b09a37 100644
--- a/tools/testing/selftests/landlock/fs_test.c
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -37,6 +37,10 @@
#include <linux/fs.h>
#include <linux/mount.h>

+/* Defines AT_CHECK without type conflicts. */
+#define _ASM_GENERIC_FCNTL_H
+#include <linux/fcntl.h>
+
#include "common.h"

#ifndef renameat2
@@ -2009,6 +2013,21 @@ static void test_execute(struct __test_metadata *const _metadata, const int err,
};
}

+static void test_check_exec(struct __test_metadata *const _metadata,
+ const int err, const char *const path)
+{
+ int ret;
+ char *const argv[] = { (char *)path, NULL };
+
+ ret = execveat(AT_FDCWD, path, argv, NULL, AT_EMPTY_PATH | AT_CHECK);
+ if (err) {
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(errno, err);
+ } else {
+ EXPECT_EQ(0, ret);
+ }
+}
+
TEST_F_FORK(layout1, execute)
{
const struct rule rules[] = {
@@ -2026,20 +2045,27 @@ TEST_F_FORK(layout1, execute)
copy_binary(_metadata, file1_s1d2);
copy_binary(_metadata, file1_s1d3);

+ /* Checks before file1_s1d1 being denied. */
+ test_execute(_metadata, 0, file1_s1d1);
+ test_check_exec(_metadata, 0, file1_s1d1);
+
enforce_ruleset(_metadata, ruleset_fd);
ASSERT_EQ(0, close(ruleset_fd));

ASSERT_EQ(0, test_open(dir_s1d1, O_RDONLY));
ASSERT_EQ(0, test_open(file1_s1d1, O_RDONLY));
test_execute(_metadata, EACCES, file1_s1d1);
+ test_check_exec(_metadata, EACCES, file1_s1d1);

ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY));
ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
test_execute(_metadata, 0, file1_s1d2);
+ test_check_exec(_metadata, 0, file1_s1d2);

ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY));
ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
test_execute(_metadata, 0, file1_s1d3);
+ test_check_exec(_metadata, 0, file1_s1d3);
}

TEST_F_FORK(layout1, link)
--
2.45.2