selftests/bpf: Add cgroup kfunc / kptr selftests

This patch adds a selftest suite to validate the cgroup kfuncs that were
added in the prior patch.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221122055458.173143-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 174 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c b/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c
new file mode 100644
index 000000000000..a59b166bbcc4
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#define _GNU_SOURCE
+#include <cgroup_helpers.h>
+#include <test_progs.h>
+
+#include "cgrp_kfunc_failure.skel.h"
+#include "cgrp_kfunc_success.skel.h"
+
+static size_t log_buf_sz = 1 << 20; /* 1 MB */
+static char obj_log_buf[1048576];
+
+static struct cgrp_kfunc_success *open_load_cgrp_kfunc_skel(void)
+{
+	struct cgrp_kfunc_success *skel;
+	int err;
+
+	skel = cgrp_kfunc_success__open();
+	if (!ASSERT_OK_PTR(skel, "skel_open"))
+		return NULL;
+
+	skel->bss->pid = getpid();
+
+	err = cgrp_kfunc_success__load(skel);
+	if (!ASSERT_OK(err, "skel_load"))
+		goto cleanup;
+
+	return skel;
+
+cleanup:
+	cgrp_kfunc_success__destroy(skel);
+	return NULL;
+}
+
+static int mkdir_rm_test_dir(void)
+{
+	int fd;
+	const char *cgrp_path = "cgrp_kfunc";
+
+	fd = create_and_get_cgroup(cgrp_path);
+	if (!ASSERT_GT(fd, 0, "mkdir_cgrp_fd"))
+		return -1;
+
+	close(fd);
+	remove_cgroup(cgrp_path);
+
+	return 0;
+}
+
+static void run_success_test(const char *prog_name)
+{
+	struct cgrp_kfunc_success *skel;
+	struct bpf_program *prog;
+	struct bpf_link *link = NULL;
+
+	skel = open_load_cgrp_kfunc_skel();
+	if (!ASSERT_OK_PTR(skel, "open_load_skel"))
+		return;
+
+	if (!ASSERT_OK(skel->bss->err, "pre_mkdir_err"))
+		goto cleanup;
+
+	prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+	if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+		goto cleanup;
+
+	link = bpf_program__attach(prog);
+	if (!ASSERT_OK_PTR(link, "attached_link"))
+		goto cleanup;
+
+	ASSERT_EQ(skel->bss->invocations, 0, "pre_rmdir_count");
+	if (!ASSERT_OK(mkdir_rm_test_dir(), "cgrp_mkdir"))
+		goto cleanup;
+
+	ASSERT_EQ(skel->bss->invocations, 1, "post_rmdir_count");
+	ASSERT_OK(skel->bss->err, "post_rmdir_err");
+
+cleanup:
+	bpf_link__destroy(link);
+	cgrp_kfunc_success__destroy(skel);
+}
+
+static const char * const success_tests[] = {
+	"test_cgrp_acquire_release_argument",
+	"test_cgrp_acquire_leave_in_map",
+	"test_cgrp_xchg_release",
+	"test_cgrp_get_release",
+};
+
+static struct {
+	const char *prog_name;
+	const char *expected_err_msg;
+} failure_tests[] = {
+	{"cgrp_kfunc_acquire_untrusted", "R1 must be referenced or trusted"},
+	{"cgrp_kfunc_acquire_fp", "arg#0 pointer type STRUCT cgroup must point"},
+	{"cgrp_kfunc_acquire_unsafe_kretprobe", "reg type unsupported for arg#0 function"},
+	{"cgrp_kfunc_acquire_trusted_walked", "R1 must be referenced or trusted"},
+	{"cgrp_kfunc_acquire_null", "arg#0 pointer type STRUCT cgroup must point"},
+	{"cgrp_kfunc_acquire_unreleased", "Unreleased reference"},
+	{"cgrp_kfunc_get_non_kptr_param", "arg#0 expected pointer to map value"},
+	{"cgrp_kfunc_get_non_kptr_acquired", "arg#0 expected pointer to map value"},
+	{"cgrp_kfunc_get_null", "arg#0 expected pointer to map value"},
+	{"cgrp_kfunc_xchg_unreleased", "Unreleased reference"},
+	{"cgrp_kfunc_get_unreleased", "Unreleased reference"},
+	{"cgrp_kfunc_release_untrusted", "arg#0 is untrusted_ptr_or_null_ expected ptr_ or socket"},
+	{"cgrp_kfunc_release_fp", "arg#0 pointer type STRUCT cgroup must point"},
+	{"cgrp_kfunc_release_null", "arg#0 is ptr_or_null_ expected ptr_ or socket"},
+	{"cgrp_kfunc_release_unacquired", "release kernel function bpf_cgroup_release expects"},
+};
+
+static void verify_fail(const char *prog_name, const char *expected_err_msg)
+{
+	LIBBPF_OPTS(bpf_object_open_opts, opts);
+	struct cgrp_kfunc_failure *skel;
+	int err, i;
+
+	opts.kernel_log_buf = obj_log_buf;
+	opts.kernel_log_size = log_buf_sz;
+	opts.kernel_log_level = 1;
+
+	skel = cgrp_kfunc_failure__open_opts(&opts);
+	if (!ASSERT_OK_PTR(skel, "cgrp_kfunc_failure__open_opts"))
+		goto cleanup;
+
+	for (i = 0; i < ARRAY_SIZE(failure_tests); i++) {
+		struct bpf_program *prog;
+		const char *curr_name = failure_tests[i].prog_name;
+
+		prog = bpf_object__find_program_by_name(skel->obj, curr_name);
+		if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+			goto cleanup;
+
+		bpf_program__set_autoload(prog, !strcmp(curr_name, prog_name));
+	}
+
+	err = cgrp_kfunc_failure__load(skel);
+	if (!ASSERT_ERR(err, "unexpected load success"))
+		goto cleanup;
+
+	if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg), "expected_err_msg")) {
+		fprintf(stderr, "Expected err_msg: %s\n", expected_err_msg);
+		fprintf(stderr, "Verifier output: %s\n", obj_log_buf);
+	}
+
+cleanup:
+	cgrp_kfunc_failure__destroy(skel);
+}
+
+void test_cgrp_kfunc(void)
+{
+	int i, err;
+
+	err = setup_cgroup_environment();
+	if (!ASSERT_OK(err, "cgrp_env_setup"))
+		goto cleanup;
+
+	for (i = 0; i < ARRAY_SIZE(success_tests); i++) {
+		if (!test__start_subtest(success_tests[i]))
+			continue;
+
+		run_success_test(success_tests[i]);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(failure_tests); i++) {
+		if (!test__start_subtest(failure_tests[i].prog_name))
+			continue;
+
+		verify_fail(failure_tests[i].prog_name, failure_tests[i].expected_err_msg);
+	}
+
+cleanup:
+	cleanup_cgroup_environment();
+}