1 files changed, 131 insertions, 0 deletions
diff --git a/tools/testing/selftests/landlock/wait-pipe-sandbox.c b/tools/testing/selftests/landlock/wait-pipe-sandbox.c
new file mode 100644
index 000000000000..87dbc9164430
--- /dev/null
+++ b/tools/testing/selftests/landlock/wait-pipe-sandbox.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Write in a pipe, wait, sandbox itself, test sandboxing, and wait again.
+ *
+ * Used by audit_exec.flags from audit_test.c
+ *
+ * Copyright © 2024-2025 Microsoft Corporation
+ */
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <linux/landlock.h>
+#include <linux/prctl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/prctl.h>
+#include <unistd.h>
+
+#include "wrappers.h"
+
+static int sync_with(int pipe_child, int pipe_parent)
+{
+	char buf;
+
+	/* Signals that we are waiting. */
+	if (write(pipe_child, ".", 1) != 1) {
+		perror("Failed to write to first argument");
+		return 1;
+	}
+
+	/* Waits for the parent do its test. */
+	if (read(pipe_parent, &buf, 1) != 1) {
+		perror("Failed to write to the second argument");
+		return 1;
+	}
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	const struct landlock_ruleset_attr layer2 = {
+		.handled_access_fs = LANDLOCK_ACCESS_FS_READ_DIR,
+	};
+	const struct landlock_ruleset_attr layer3 = {
+		.scoped = LANDLOCK_SCOPE_SIGNAL,
+	};
+	int err, pipe_child, pipe_parent, ruleset_fd;
+
+	/* The first argument must be the file descriptor number of a pipe. */
+	if (argc != 3) {
+		fprintf(stderr, "Wrong number of arguments (not two)\n");
+		return 1;
+	}
+
+	pipe_child = atoi(argv[1]);
+	pipe_parent = atoi(argv[2]);
+	/* PR_SET_NO_NEW_PRIVS already set by parent. */
+
+	/* First step to test parent's layer1. */
+	err = sync_with(pipe_child, pipe_parent);
+	if (err)
+		return err;
+
+	/* Tries to send a signal, denied by layer1. */
+	if (!kill(getppid(), 0)) {
+		fprintf(stderr, "Successfully sent a signal to the parent");
+		return 1;
+	}
+
+	/* Second step to test parent's layer1 and our layer2. */
+	err = sync_with(pipe_child, pipe_parent);
+	if (err)
+		return err;
+
+	ruleset_fd = landlock_create_ruleset(&layer2, sizeof(layer2), 0);
+	if (ruleset_fd < 0) {
+		perror("Failed to create the layer2 ruleset");
+		return 1;
+	}
+
+	if (landlock_restrict_self(ruleset_fd, 0)) {
+		perror("Failed to restrict self");
+		return 1;
+	}
+	close(ruleset_fd);
+
+	/* Tries to send a signal, denied by layer1. */
+	if (!kill(getppid(), 0)) {
+		fprintf(stderr, "Successfully sent a signal to the parent");
+		return 1;
+	}
+
+	/* Tries to open ., denied by layer2. */
+	if (open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC) >= 0) {
+		fprintf(stderr, "Successfully opened /");
+		return 1;
+	}
+
+	/* Third step to test our layer2 and layer3. */
+	err = sync_with(pipe_child, pipe_parent);
+	if (err)
+		return err;
+
+	ruleset_fd = landlock_create_ruleset(&layer3, sizeof(layer3), 0);
+	if (ruleset_fd < 0) {
+		perror("Failed to create the layer3 ruleset");
+		return 1;
+	}
+
+	if (landlock_restrict_self(ruleset_fd, 0)) {
+		perror("Failed to restrict self");
+		return 1;
+	}
+	close(ruleset_fd);
+
+	/* Tries to open ., denied by layer2. */
+	if (open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC) >= 0) {
+		fprintf(stderr, "Successfully opened /");
+		return 1;
+	}
+
+	/* Tries to send a signal, denied by layer3. */
+	if (!kill(getppid(), 0)) {
+		fprintf(stderr, "Successfully sent a signal to the parent");
+		return 1;
+	}
+
+	return 0;
+}