[LTP] [PATCH v4 1/5] Add landlock03 test

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

This test verifies that landlock_restrict_self syscall fails with the
right error codes:

- EINVAL flags is not 0
- EBADF ruleset_fd is not a file descriptor for the current thread
- EBADFD ruleset_fd is not a ruleset file descriptor
- EPERM ruleset doesn't have CAP_SYS_ADMIN in its namespace
- E2BIG The maximum number of stacked rulesets is reached for the
  current thread

Reviewed-by: Li Wang <liwang@redhat.com>
Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
 runtest/syscalls                                |   1 +
 testcases/kernel/syscalls/landlock/.gitignore   |   1 +
 testcases/kernel/syscalls/landlock/landlock03.c | 128 ++++++++++++++++++++++++
 3 files changed, 130 insertions(+)

diff --git a/runtest/syscalls b/runtest/syscalls
index 8f9e06e73..9b3cba667 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -698,6 +698,7 @@ kill13 kill13
 
 landlock01 landlock01
 landlock02 landlock02
+landlock03 landlock03
 
 lchown01 lchown01
 lchown01_16 lchown01_16
diff --git a/testcases/kernel/syscalls/landlock/.gitignore b/testcases/kernel/syscalls/landlock/.gitignore
index ffed4abd2..f79cd090b 100644
--- a/testcases/kernel/syscalls/landlock/.gitignore
+++ b/testcases/kernel/syscalls/landlock/.gitignore
@@ -1,2 +1,3 @@
 landlock01
 landlock02
+landlock03
diff --git a/testcases/kernel/syscalls/landlock/landlock03.c b/testcases/kernel/syscalls/landlock/landlock03.c
new file mode 100644
index 000000000..c70d23885
--- /dev/null
+++ b/testcases/kernel/syscalls/landlock/landlock03.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * This test verifies that landlock_restrict_self syscall fails with the right
+ * error codes:
+ *
+ * - EINVAL flags is not 0
+ * - EBADF ruleset_fd is not a file descriptor for the current thread
+ * - EBADFD ruleset_fd is not a ruleset file descriptor
+ * - EPERM ruleset doesn't have CAP_SYS_ADMIN in its namespace
+ * - E2BIG The maximum number of stacked rulesets is reached for the current
+ *   thread
+ */
+
+#include "landlock_common.h"
+
+#define MAX_STACKED_RULESETS 16
+
+static struct landlock_ruleset_attr *ruleset_attr;
+static int ruleset_fd = -1;
+static int ruleset_invalid = -1;
+static int file_fd = -1;
+
+static struct tst_cap dropadmin = {
+	.action = TST_CAP_DROP,
+	.id = CAP_SYS_ADMIN,
+	.name = "CAP_SYS_ADMIN",
+};
+
+static struct tst_cap needadmin = {
+	.action = TST_CAP_REQ,
+	.id = CAP_SYS_ADMIN,
+	.name = "CAP_SYS_ADMIN",
+};
+
+static struct tcase {
+	int *fd;
+	uint32_t flags;
+	int exp_errno;
+	char *msg;
+} tcases[] = {
+	{&ruleset_fd, -1, EINVAL, "Invalid flags"},
+	{&ruleset_invalid, 0, EBADF, "Invalid file descriptor"},
+	{&file_fd, 0, EBADFD, "Not a ruleset file descriptor"},
+	{&ruleset_fd, 0, EPERM, "File descriptor doesn't have CAP_SYS_ADMIN"},
+	{&ruleset_fd, 0, E2BIG, "Maximum number of stacked rulesets is reached"},
+};
+
+static void run_child(struct tcase *tc)
+{
+	if (tc->exp_errno == EPERM)
+		tst_cap_action(&dropadmin);
+
+	if (tc->exp_errno == E2BIG) {
+		for (int i = 0; i < MAX_STACKED_RULESETS; i++) {
+			TST_EXP_PASS_SILENT(tst_syscall(__NR_landlock_restrict_self,
+				*tc->fd, tc->flags));
+			if (TST_RET == -1)
+				return;
+		}
+	}
+
+	TST_EXP_FAIL(tst_syscall(__NR_landlock_restrict_self, *tc->fd, tc->flags),
+		tc->exp_errno,
+		"%s", tc->msg);
+
+	if (tc->exp_errno == EPERM)
+		tst_cap_action(&needadmin);
+}
+
+static void run(unsigned int n)
+{
+	struct tcase *tc = &tcases[n];
+
+	if (!SAFE_FORK()) {
+		run_child(tc);
+		_exit(0);
+	}
+}
+
+static void setup(void)
+{
+	verify_landlock_is_enabled();
+
+	ruleset_attr->handled_access_fs = LANDLOCK_ACCESS_FS_EXECUTE;
+
+	ruleset_fd = TST_EXP_FD_SILENT(tst_syscall(__NR_landlock_create_ruleset,
+		ruleset_attr, sizeof(struct landlock_ruleset_attr), 0));
+
+	file_fd = SAFE_OPEN("junk.bin", O_CREAT, 0777);
+}
+
+static void cleanup(void)
+{
+	if (ruleset_fd != -1)
+		SAFE_CLOSE(ruleset_fd);
+
+	if (file_fd != -1)
+		SAFE_CLOSE(file_fd);
+}
+
+static struct tst_test test = {
+	.test = run,
+	.tcnt = ARRAY_SIZE(tcases),
+	.setup = setup,
+	.cleanup = cleanup,
+	.min_kver = "5.13",
+	.needs_tmpdir = 1,
+	.needs_root = 1,
+	.forks_child = 1,
+	.needs_kconfigs = (const char *[]) {
+		"CONFIG_SECURITY_LANDLOCK=y",
+		NULL
+	},
+	.bufs = (struct tst_buffers []) {
+		{&ruleset_attr, .size = sizeof(struct landlock_ruleset_attr)},
+		{},
+	},
+	.caps = (struct tst_cap []) {
+		TST_CAP(TST_CAP_REQ, CAP_SYS_ADMIN),
+		{}
+	},
+};

-- 
2.43.0