// SPDX-License-Identifier: GPL-2.0

/*
 * Copyright (C) 2020 Google LLC.
 */

#include <test_progs.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <unistd.h>
#include <malloc.h>
#include <stdlib.h>

#include "lsm.skel.h"
#include "lsm_tailcall.skel.h"

char *CMD_ARGS[] = {"true", NULL};

#define GET_PAGE_ADDR(ADDR, PAGE_SIZE)                                  \
        (char *)(((unsigned long) (ADDR + PAGE_SIZE)) & ~(PAGE_SIZE-1))

int stack_mprotect(void)
{
        void *buf;
        long sz;
        int ret;

        sz = sysconf(_SC_PAGESIZE);
        if (sz < 0)
                return sz;

        buf = alloca(sz * 3);
        ret = mprotect(GET_PAGE_ADDR(buf, sz), sz,
                       PROT_READ | PROT_WRITE | PROT_EXEC);
        return ret;
}

int exec_cmd(int *monitored_pid)
{
        int child_pid, child_status;

        child_pid = fork();
        if (child_pid == 0) {
                *monitored_pid = getpid();
                execvp(CMD_ARGS[0], CMD_ARGS);
                return -EINVAL;
        } else if (child_pid > 0) {
                waitpid(child_pid, &child_status, 0);
                return child_status;
        }

        return -EINVAL;
}

static int test_lsm(struct lsm *skel)
{
        struct bpf_link *link;
        int buf = 1234;
        int err;

        err = lsm__attach(skel);
        if (!ASSERT_OK(err, "attach"))
                return err;

        /* Check that already linked program can't be attached again. */
        link = bpf_program__attach(skel->progs.test_int_hook);
        if (!ASSERT_ERR_PTR(link, "attach_link"))
                return -1;

        err = exec_cmd(&skel->bss->monitored_pid);
        if (!ASSERT_OK(err, "exec_cmd"))
                return err;

        ASSERT_EQ(skel->bss->bprm_count, 1, "bprm_count");

        skel->bss->monitored_pid = getpid();

        err = stack_mprotect();
        if (!ASSERT_EQ(err, -1, "stack_mprotect") ||
            !ASSERT_EQ(errno, EPERM, "stack_mprotect"))
                return err;

        ASSERT_EQ(skel->bss->mprotect_count, 1, "mprotect_count");

        syscall(__NR_setdomainname, &buf, -2L);
        syscall(__NR_setdomainname, 0, -3L);
        syscall(__NR_setdomainname, ~0L, -4L);

        ASSERT_EQ(skel->bss->copy_test, 3, "copy_test");

        lsm__detach(skel);

        skel->bss->copy_test = 0;
        skel->bss->bprm_count = 0;
        skel->bss->mprotect_count = 0;
        return 0;
}

static void test_lsm_basic(void)
{
        struct lsm *skel = NULL;
        int err;

        skel = lsm__open_and_load();
        if (!ASSERT_OK_PTR(skel, "lsm_skel_load"))
                goto close_prog;

        err = test_lsm(skel);
        if (!ASSERT_OK(err, "test_lsm_first_attach"))
                goto close_prog;

        err = test_lsm(skel);
        ASSERT_OK(err, "test_lsm_second_attach");

close_prog:
        lsm__destroy(skel);
}

static void test_lsm_tailcall(void)
{
        struct lsm_tailcall *skel = NULL;
        int map_fd, prog_fd;
        int err, key;

        skel = lsm_tailcall__open_and_load();
        if (!ASSERT_OK_PTR(skel, "lsm_tailcall__skel_load"))
                goto close_prog;

        map_fd = bpf_map__fd(skel->maps.jmp_table);
        if (CHECK_FAIL(map_fd < 0))
                goto close_prog;

        prog_fd = bpf_program__fd(skel->progs.lsm_file_permission_prog);
        if (CHECK_FAIL(prog_fd < 0))
                goto close_prog;

        key = 0;
        err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
        if (CHECK_FAIL(!err))
                goto close_prog;

        prog_fd = bpf_program__fd(skel->progs.lsm_kernfs_init_security_prog);
        if (CHECK_FAIL(prog_fd < 0))
                goto close_prog;

        err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
        if (CHECK_FAIL(err))
                goto close_prog;

close_prog:
        lsm_tailcall__destroy(skel);
}

void test_test_lsm(void)
{
        if (test__start_subtest("lsm_basic"))
                test_lsm_basic();
        if (test__start_subtest("lsm_tailcall"))
                test_lsm_tailcall();
}