// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <test_progs.h>
#include "test_deny_namespace.skel.h"
#include <sched.h>
#include "cap_helpers.h"
#include <stdio.h>

static int wait_for_pid(pid_t pid)
{
        int status, ret;

again:
        ret = waitpid(pid, &status, 0);
        if (ret == -1) {
                if (errno == EINTR)
                        goto again;

                return -1;
        }

        if (!WIFEXITED(status))
                return -1;

        return WEXITSTATUS(status);
}

/* negative return value -> some internal error
 * positive return value -> userns creation failed
 * 0                     -> userns creation succeeded
 */
static int create_user_ns(void)
{
        pid_t pid;

        pid = fork();
        if (pid < 0)
                return -1;

        if (pid == 0) {
                if (unshare(CLONE_NEWUSER))
                        _exit(EXIT_FAILURE);
                _exit(EXIT_SUCCESS);
        }

        return wait_for_pid(pid);
}

static void test_userns_create_bpf(void)
{
        __u32 cap_mask = 1ULL << CAP_SYS_ADMIN;
        __u64 old_caps = 0;

        cap_enable_effective(cap_mask, &old_caps);

        ASSERT_OK(create_user_ns(), "priv new user ns");

        cap_disable_effective(cap_mask, &old_caps);

        ASSERT_EQ(create_user_ns(), EPERM, "unpriv new user ns");

        if (cap_mask & old_caps)
                cap_enable_effective(cap_mask, NULL);
}

static void test_unpriv_userns_create_no_bpf(void)
{
        __u32 cap_mask = 1ULL << CAP_SYS_ADMIN;
        __u64 old_caps = 0;

        cap_disable_effective(cap_mask, &old_caps);

        ASSERT_OK(create_user_ns(), "no-bpf unpriv new user ns");

        if (cap_mask & old_caps)
                cap_enable_effective(cap_mask, NULL);
}

void test_deny_namespace(void)
{
        struct test_deny_namespace *skel = NULL;
        int err;

        if (test__start_subtest("unpriv_userns_create_no_bpf"))
                test_unpriv_userns_create_no_bpf();

        skel = test_deny_namespace__open_and_load();
        if (!ASSERT_OK_PTR(skel, "skel load"))
                goto close_prog;

        err = test_deny_namespace__attach(skel);
        if (!ASSERT_OK(err, "attach"))
                goto close_prog;

        if (test__start_subtest("userns_create_bpf"))
                test_userns_create_bpf();

        test_deny_namespace__detach(skel);

close_prog:
        test_deny_namespace__destroy(skel);
}