selftests/bpf: add sockopt clone/inheritance test

Add a test that calls setsockopt on the listener socket which triggers
BPF program. This BPF program writes to the sk storage and sets
clone flag. Make sure that sk storage is cloned for a newly
accepted connection.

We have two cloned maps in the tests to make sure we hit both cases
in bpf_sk_storage_clone: first element (sk_storage_alloc) and
non-first element(s) (selem_link_map).

Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 253 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/test_sockopt_inherit.c b/tools/testing/selftests/bpf/test_sockopt_inherit.c
new file mode 100644
index 000000000000..1bf699815b9b
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_sockopt_inherit.c
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <error.h>
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <pthread.h>
+
+#include <linux/filter.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "bpf_rlimit.h"
+#include "bpf_util.h"
+#include "cgroup_helpers.h"
+
+#define CG_PATH				"/sockopt_inherit"
+#define SOL_CUSTOM			0xdeadbeef
+#define CUSTOM_INHERIT1			0
+#define CUSTOM_INHERIT2			1
+#define CUSTOM_LISTENER			2
+
+static int connect_to_server(int server_fd)
+{
+	struct sockaddr_storage addr;
+	socklen_t len = sizeof(addr);
+	int fd;
+
+	fd = socket(AF_INET, SOCK_STREAM, 0);
+	if (fd < 0) {
+		log_err("Failed to create client socket");
+		return -1;
+	}
+
+	if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
+		log_err("Failed to get server addr");
+		goto out;
+	}
+
+	if (connect(fd, (const struct sockaddr *)&addr, len) < 0) {
+		log_err("Fail to connect to server");
+		goto out;
+	}
+
+	return fd;
+
+out:
+	close(fd);
+	return -1;
+}
+
+static int verify_sockopt(int fd, int optname, const char *msg, char expected)
+{
+	socklen_t optlen = 1;
+	char buf = 0;
+	int err;
+
+	err = getsockopt(fd, SOL_CUSTOM, optname, &buf, &optlen);
+	if (err) {
+		log_err("%s: failed to call getsockopt", msg);
+		return 1;
+	}
+
+	printf("%s %d: got=0x%x ? expected=0x%x\n", msg, optname, buf, expected);
+
+	if (buf != expected) {
+		log_err("%s: unexpected getsockopt value %d != %d", msg,
+			buf, expected);
+		return 1;
+	}
+
+	return 0;
+}
+
+static void *server_thread(void *arg)
+{
+	struct sockaddr_storage addr;
+	socklen_t len = sizeof(addr);
+	int fd = *(int *)arg;
+	int client_fd;
+	int err = 0;
+
+	if (listen(fd, 1) < 0)
+		error(1, errno, "Failed to listed on socket");
+
+	err += verify_sockopt(fd, CUSTOM_INHERIT1, "listen", 1);
+	err += verify_sockopt(fd, CUSTOM_INHERIT2, "listen", 1);
+	err += verify_sockopt(fd, CUSTOM_LISTENER, "listen", 1);
+
+	client_fd = accept(fd, (struct sockaddr *)&addr, &len);
+	if (client_fd < 0)
+		error(1, errno, "Failed to accept client");
+
+	err += verify_sockopt(client_fd, CUSTOM_INHERIT1, "accept", 1);
+	err += verify_sockopt(client_fd, CUSTOM_INHERIT2, "accept", 1);
+	err += verify_sockopt(client_fd, CUSTOM_LISTENER, "accept", 0);
+
+	close(client_fd);
+
+	return (void *)(long)err;
+}
+
+static int start_server(void)
+{
+	struct sockaddr_in addr = {
+		.sin_family = AF_INET,
+		.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
+	};
+	char buf;
+	int err;
+	int fd;
+	int i;
+
+	fd = socket(AF_INET, SOCK_STREAM, 0);
+	if (fd < 0) {
+		log_err("Failed to create server socket");
+		return -1;
+	}
+
+	for (i = CUSTOM_INHERIT1; i <= CUSTOM_LISTENER; i++) {
+		buf = 0x01;
+		err = setsockopt(fd, SOL_CUSTOM, i, &buf, 1);
+		if (err) {
+			log_err("Failed to call setsockopt(%d)", i);
+			close(fd);
+			return -1;
+		}
+	}
+
+	if (bind(fd, (const struct sockaddr *)&addr, sizeof(addr)) < 0) {
+		log_err("Failed to bind socket");
+		close(fd);
+		return -1;
+	}
+
+	return fd;
+}
+
+static int prog_attach(struct bpf_object *obj, int cgroup_fd, const char *title)
+{
+	enum bpf_attach_type attach_type;
+	enum bpf_prog_type prog_type;
+	struct bpf_program *prog;
+	int err;
+
+	err = libbpf_prog_type_by_name(title, &prog_type, &attach_type);
+	if (err) {
+		log_err("Failed to deduct types for %s BPF program", title);
+		return -1;
+	}
+
+	prog = bpf_object__find_program_by_title(obj, title);
+	if (!prog) {
+		log_err("Failed to find %s BPF program", title);
+		return -1;
+	}
+
+	err = bpf_prog_attach(bpf_program__fd(prog), cgroup_fd,
+			      attach_type, 0);
+	if (err) {
+		log_err("Failed to attach %s BPF program", title);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int run_test(int cgroup_fd)
+{
+	struct bpf_prog_load_attr attr = {
+		.file = "./sockopt_inherit.o",
+	};
+	int server_fd = -1, client_fd;
+	struct bpf_object *obj;
+	void *server_err;
+	pthread_t tid;
+	int ignored;
+	int err;
+
+	err = bpf_prog_load_xattr(&attr, &obj, &ignored);
+	if (err) {
+		log_err("Failed to load BPF object");
+		return -1;
+	}
+
+	err = prog_attach(obj, cgroup_fd, "cgroup/getsockopt");
+	if (err)
+		goto close_bpf_object;
+
+	err = prog_attach(obj, cgroup_fd, "cgroup/setsockopt");
+	if (err)
+		goto close_bpf_object;
+
+	server_fd = start_server();
+	if (server_fd < 0) {
+		err = -1;
+		goto close_bpf_object;
+	}
+
+	pthread_create(&tid, NULL, server_thread, (void *)&server_fd);
+
+	client_fd = connect_to_server(server_fd);
+	if (client_fd < 0) {
+		err = -1;
+		goto close_server_fd;
+	}
+
+	err += verify_sockopt(client_fd, CUSTOM_INHERIT1, "connect", 0);
+	err += verify_sockopt(client_fd, CUSTOM_INHERIT2, "connect", 0);
+	err += verify_sockopt(client_fd, CUSTOM_LISTENER, "connect", 0);
+
+	pthread_join(tid, &server_err);
+
+	err += (int)(long)server_err;
+
+	close(client_fd);
+
+close_server_fd:
+	close(server_fd);
+close_bpf_object:
+	bpf_object__close(obj);
+	return err;
+}
+
+int main(int args, char **argv)
+{
+	int cgroup_fd;
+	int err = EXIT_SUCCESS;
+
+	if (setup_cgroup_environment())
+		return err;
+
+	cgroup_fd = create_and_get_cgroup(CG_PATH);
+	if (cgroup_fd < 0)
+		goto cleanup_cgroup_env;
+
+	if (join_cgroup(CG_PATH))
+		goto cleanup_cgroup;
+
+	if (run_test(cgroup_fd))
+		err = EXIT_FAILURE;
+
+	printf("test_sockopt_inherit: %s\n",
+	       err == EXIT_SUCCESS ? "PASSED" : "FAILED");
+
+cleanup_cgroup:
+	close(cgroup_fd);
+cleanup_cgroup_env:
+	cleanup_cgroup_environment();
+	return err;
+}