1 files changed, 82 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_dev_cgroup.c b/tools/testing/selftests/bpf/test_dev_cgroup.c
new file mode 100644
index 000000000..804dddd97
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_dev_cgroup.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2017 Facebook
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <sys/time.h>
+
+#include <linux/bpf.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "cgroup_helpers.h"
+#include "bpf_rlimit.h"
+
+#define DEV_CGROUP_PROG "./dev_cgroup.o"
+
+#define TEST_CGROUP "/test-bpf-based-device-cgroup/"
+
+int main(int argc, char **argv)
+{
+	struct bpf_object *obj;
+	int error = EXIT_FAILURE;
+	int prog_fd, cgroup_fd;
+	__u32 prog_cnt;
+
+	if (bpf_prog_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
+			  &obj, &prog_fd)) {
+		printf("Failed to load DEV_CGROUP program\n");
+		goto out;
+	}
+
+	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
+	if (cgroup_fd < 0) {
+		printf("Failed to create test cgroup\n");
+		goto out;
+	}
+
+	/* Attach bpf program */
+	if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
+		printf("Failed to attach DEV_CGROUP program");
+		goto err;
+	}
+
+	if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
+			   &prog_cnt)) {
+		printf("Failed to query attached programs");
+		goto err;
+	}
+
+	/* All operations with /dev/zero and and /dev/urandom are allowed,
+	 * everything else is forbidden.
+	 */
+	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
+	assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
+	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
+
+	/* /dev/zero is whitelisted */
+	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
+	assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
+	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
+
+	assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
+
+	/* src is allowed, target is forbidden */
+	assert(system("dd if=/dev/urandom of=/dev/full count=64"));
+
+	/* src is forbidden, target is allowed */
+	assert(system("dd if=/dev/random of=/dev/zero count=64"));
+
+	error = 0;
+	printf("test_dev_cgroup:PASS\n");
+
+err:
+	cleanup_cgroup_environment();
+
+out:
+	return error;
+}