tools/testing/selftests/bpf/prog_tests/lsm_cgroup.c

// SPDX-License-Identifier: GPL-2.0

#include <sys/types.h>
#include <sys/socket.h>
#include <test_progs.h>
#include <bpf/btf.h>

#include "lsm_cgroup.skel.h"
#include "lsm_cgroup_nonvoid.skel.h"
#include "cgroup_helpers.h"
#include "network_helpers.h"

#ifndef ENOTSUPP
#define ENOTSUPP 524
#endif

static struct btf *btf;

static __u32 query_prog_cnt(int cgroup_fd, const char *attach_func)
{
	LIBBPF_OPTS(bpf_prog_query_opts, p);
	int cnt = 0;
	int i;

	ASSERT_OK(bpf_prog_query_opts(cgroup_fd, BPF_LSM_CGROUP, &p), "prog_query");

	if (!attach_func)
		return p.prog_cnt;

	/* When attach_func is provided, count the number of progs that
	 * attach to the given symbol.
	 */

	if (!btf)
		btf = btf__load_vmlinux_btf();
	if (!ASSERT_OK(libbpf_get_error(btf), "btf_vmlinux"))
		return -1;

	p.prog_ids = malloc(sizeof(u32) * p.prog_cnt);
	p.prog_attach_flags = malloc(sizeof(u32) * p.prog_cnt);
	ASSERT_OK(bpf_prog_query_opts(cgroup_fd, BPF_LSM_CGROUP, &p), "prog_query");

	for (i = 0; i < p.prog_cnt; i++) {
		struct bpf_prog_info info = {};
		__u32 info_len = sizeof(info);
		int fd;

		fd = bpf_prog_get_fd_by_id(p.prog_ids[i]);
		ASSERT_GE(fd, 0, "prog_get_fd_by_id");
		ASSERT_OK(bpf_prog_get_info_by_fd(fd, &info, &info_len),
			  "prog_info_by_fd");
		close(fd);

		if (info.attach_btf_id ==
		    btf__find_by_name_kind(btf, attach_func, BTF_KIND_FUNC))
			cnt++;
	}

	free(p.prog_ids);
	free(p.prog_attach_flags);

	return cnt;
}

static void test_lsm_cgroup_functional(void)
{
	DECLARE_LIBBPF_OPTS(bpf_prog_attach_opts, attach_opts);
	DECLARE_LIBBPF_OPTS(bpf_link_update_opts, update_opts);
	int cgroup_fd = -1, cgroup_fd2 = -1, cgroup_fd3 = -1;
	int listen_fd, client_fd, accepted_fd;
	struct lsm_cgroup *skel = NULL;
	int post_create_prog_fd2 = -1;
	int post_create_prog_fd = -1;
	int bind_link_fd2 = -1;
	int bind_prog_fd2 = -1;
	int alloc_prog_fd = -1;
	int bind_prog_fd = -1;
	int bind_link_fd = -1;
	int clone_prog_fd = -1;
	int err, fd, prio;
	socklen_t socklen;

	cgroup_fd3 = test__join_cgroup("/sock_policy_empty");
	if (!ASSERT_GE(cgroup_fd3, 0, "create empty cgroup"))
		goto close_cgroup;

	cgroup_fd2 = test__join_cgroup("/sock_policy_reuse");
	if (!ASSERT_GE(cgroup_fd2, 0, "create cgroup for reuse"))
		goto close_cgroup;

	cgroup_fd = test__join_cgroup("/sock_policy");
	if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup"))
		goto close_cgroup;

	skel = lsm_cgroup__open_and_load();
	if (!ASSERT_OK_PTR(skel, "open_and_load"))
		goto close_cgroup;

	post_create_prog_fd = bpf_program__fd(skel->progs.socket_post_create);
	post_create_prog_fd2 = bpf_program__fd(skel->progs.socket_post_create2);
	bind_prog_fd = bpf_program__fd(skel->progs.socket_bind);
	bind_prog_fd2 = bpf_program__fd(skel->progs.socket_bind2);
	alloc_prog_fd = bpf_program__fd(skel->progs.socket_alloc);
	clone_prog_fd = bpf_program__fd(skel->progs.socket_clone);

	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_sk_alloc_security"), 0, "prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 0, "total prog count");
	err = bpf_prog_attach(alloc_prog_fd, cgroup_fd, BPF_LSM_CGROUP, 0);
	if (err == -ENOTSUPP) {
		test__skip();
		goto close_cgroup;
	}
	if (!ASSERT_OK(err, "attach alloc_prog_fd"))
		goto detach_cgroup;
	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_sk_alloc_security"), 1, "prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 1, "total prog count");

	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_inet_csk_clone"), 0, "prog count");
	err = bpf_prog_attach(clone_prog_fd, cgroup_fd, BPF_LSM_CGROUP, 0);
	if (!ASSERT_OK(err, "attach clone_prog_fd"))
		goto detach_cgroup;
	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_inet_csk_clone"), 1, "prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 2, "total prog count");

	/* Make sure replacing works. */

	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_socket_post_create"), 0, "prog count");
	err = bpf_prog_attach(post_create_prog_fd, cgroup_fd,
			      BPF_LSM_CGROUP, 0);
	if (!ASSERT_OK(err, "attach post_create_prog_fd"))
		goto detach_cgroup;
	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_socket_post_create"), 1, "prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 3, "total prog count");

	attach_opts.replace_prog_fd = post_create_prog_fd;
	err = bpf_prog_attach_opts(post_create_prog_fd2, cgroup_fd,
				   BPF_LSM_CGROUP, &attach_opts);
	if (!ASSERT_OK(err, "prog replace post_create_prog_fd"))
		goto detach_cgroup;
	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_socket_post_create"), 1, "prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 3, "total prog count");

	/* Try the same attach/replace via link API. */

	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_socket_bind"), 0, "prog count");
	bind_link_fd = bpf_link_create(bind_prog_fd, cgroup_fd,
				       BPF_LSM_CGROUP, NULL);
	if (!ASSERT_GE(bind_link_fd, 0, "link create bind_prog_fd"))
		goto detach_cgroup;
	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_socket_bind"), 1, "prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 4, "total prog count");

	update_opts.old_prog_fd = bind_prog_fd;
	update_opts.flags = BPF_F_REPLACE;

	err = bpf_link_update(bind_link_fd, bind_prog_fd2, &update_opts);
	if (!ASSERT_OK(err, "link update bind_prog_fd"))
		goto detach_cgroup;
	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_socket_bind"), 1, "prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 4, "total prog count");

	/* Attach another instance of bind program to another cgroup.
	 * This should trigger the reuse of the trampoline shim (two
	 * programs attaching to the same btf_id).
	 */

	ASSERT_EQ(query_prog_cnt(cgroup_fd, "bpf_lsm_socket_bind"), 1, "prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd2, "bpf_lsm_socket_bind"), 0, "prog count");
	bind_link_fd2 = bpf_link_create(bind_prog_fd2, cgroup_fd2,
					BPF_LSM_CGROUP, NULL);
	if (!ASSERT_GE(bind_link_fd2, 0, "link create bind_prog_fd2"))
		goto detach_cgroup;
	ASSERT_EQ(query_prog_cnt(cgroup_fd2, "bpf_lsm_socket_bind"), 1, "prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd, NULL), 4, "total prog count");
	ASSERT_EQ(query_prog_cnt(cgroup_fd2, NULL), 1, "total prog count");

	fd = socket(AF_UNIX, SOCK_STREAM, 0);
	if (!(skel->kconfig->CONFIG_SECURITY_APPARMOR
	    || skel->kconfig->CONFIG_SECURITY_SELINUX
	    || skel->kconfig->CONFIG_SECURITY_SMACK))
		/* AF_UNIX is prohibited. */
		ASSERT_LT(fd, 0, "socket(AF_UNIX)");
	close(fd);

	/* AF_INET6 gets default policy (sk_priority). */

	fd = socket(AF_INET6, SOCK_STREAM, 0);
	if (!ASSERT_GE(fd, 0, "socket(SOCK_STREAM)"))
		goto detach_cgroup;

	prio = 0;
	socklen = sizeof(prio);
	ASSERT_GE(getsockopt(fd, SOL_SOCKET, SO_PRIORITY, &prio, &socklen), 0,
		  "getsockopt");
	ASSERT_EQ(prio, 123, "sk_priority");

	close(fd);

	/* TX-only AF_PACKET is allowed. */

	ASSERT_LT(socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL)), 0,
		  "socket(AF_PACKET, ..., ETH_P_ALL)");

	fd = socket(AF_PACKET, SOCK_RAW, 0);
	ASSERT_GE(fd, 0, "socket(AF_PACKET, ..., 0)");

	/* TX-only AF_PACKET can not be rebound. */

	struct sockaddr_ll sa = {
		.sll_family = AF_PACKET,
		.sll_protocol = htons(ETH_P_ALL),
	};
	ASSERT_LT(bind(fd, (struct sockaddr *)&sa, sizeof(sa)), 0,
		  "bind(ETH_P_ALL)");

	close(fd);

	/* Trigger passive open. */

	listen_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
	ASSERT_GE(listen_fd, 0, "start_server");
	client_fd = connect_to_fd(listen_fd, 0);
	ASSERT_GE(client_fd, 0, "connect_to_fd");
	accepted_fd = accept(listen_fd, NULL, NULL);
	ASSERT_GE(accepted_fd, 0, "accept");

	prio = 0;
	socklen = sizeof(prio);
	ASSERT_GE(getsockopt(accepted_fd, SOL_SOCKET, SO_PRIORITY, &prio, &socklen), 0,
		  "getsockopt");
	ASSERT_EQ(prio, 234, "sk_priority");

	/* These are replaced and never called. */
	ASSERT_EQ(skel->bss->called_socket_post_create, 0, "called_create");
	ASSERT_EQ(skel->bss->called_socket_bind, 0, "called_bind");

	/* AF_INET6+SOCK_STREAM
	 * AF_PACKET+SOCK_RAW
	 * AF_UNIX+SOCK_RAW if already have non-bpf lsms installed
	 * listen_fd
	 * client_fd
	 * accepted_fd
	 */
	if (skel->kconfig->CONFIG_SECURITY_APPARMOR
	    || skel->kconfig->CONFIG_SECURITY_SELINUX
	    || skel->kconfig->CONFIG_SECURITY_SMACK)
		/* AF_UNIX+SOCK_RAW if already have non-bpf lsms installed */
		ASSERT_EQ(skel->bss->called_socket_post_create2, 6, "called_create2");
	else
		ASSERT_EQ(skel->bss->called_socket_post_create2, 5, "called_create2");

	/* start_server
	 * bind(ETH_P_ALL)
	 */
	ASSERT_EQ(skel->bss->called_socket_bind2, 2, "called_bind2");
	/* Single accept(). */
	ASSERT_EQ(skel->bss->called_socket_clone, 1, "called_clone");

	/* AF_UNIX+SOCK_STREAM (failed)
	 * AF_INET6+SOCK_STREAM
	 * AF_PACKET+SOCK_RAW (failed)
	 * AF_PACKET+SOCK_RAW
	 * listen_fd
	 * client_fd
	 * accepted_fd
	 */
	ASSERT_EQ(skel->bss->called_socket_alloc, 7, "called_alloc");

	close(listen_fd);
	close(client_fd);
	close(accepted_fd);

	/* Make sure other cgroup doesn't trigger the programs. */

	if (!ASSERT_OK(join_cgroup("/sock_policy_empty"), "join root cgroup"))
		goto detach_cgroup;

	fd = socket(AF_INET6, SOCK_STREAM, 0);
	if (!ASSERT_GE(fd, 0, "socket(SOCK_STREAM)"))
		goto detach_cgroup;

	prio = 0;
	socklen = sizeof(prio);
	ASSERT_GE(getsockopt(fd, SOL_SOCKET, SO_PRIORITY, &prio, &socklen), 0,
		  "getsockopt");
	ASSERT_EQ(prio, 0, "sk_priority");

	close(fd);

detach_cgroup:
	ASSERT_GE(bpf_prog_detach2(post_create_prog_fd2, cgroup_fd,
				   BPF_LSM_CGROUP), 0, "detach_create");
	close(bind_link_fd);
	/* Don't close bind_link_fd2, exercise cgroup release cleanup. */
	ASSERT_GE(bpf_prog_detach2(alloc_prog_fd, cgroup_fd,
				   BPF_LSM_CGROUP), 0, "detach_alloc");
	ASSERT_GE(bpf_prog_detach2(clone_prog_fd, cgroup_fd,
				   BPF_LSM_CGROUP), 0, "detach_clone");

close_cgroup:
	close(cgroup_fd);
	close(cgroup_fd2);
	close(cgroup_fd3);
	lsm_cgroup__destroy(skel);
}

static void test_lsm_cgroup_nonvoid(void)
{
	struct lsm_cgroup_nonvoid *skel = NULL;

	skel = lsm_cgroup_nonvoid__open_and_load();
	ASSERT_NULL(skel, "open succeeds");
	lsm_cgroup_nonvoid__destroy(skel);
}

void test_lsm_cgroup(void)
{
	if (test__start_subtest("functional"))
		test_lsm_cgroup_functional();
	if (test__start_subtest("nonvoid"))
		test_lsm_cgroup_nonvoid();
	btf__free(btf);
}