// SPDX-License-Identifier: GPL-2.0
/*
 * Linux Security Module infrastructure tests
 *
 * Copyright © 2023 Casey Schaufler <casey@schaufler-ca.com>
 */

#define _GNU_SOURCE
#include <linux/lsm.h>
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include "common.h"

#define PROCATTR "/proc/self/attr/"

int read_proc_attr(const char *attr, char *value, size_t size)
{
        int fd;
        int len;
        char *path;

        len = strlen(PROCATTR) + strlen(attr) + 1;
        path = calloc(len, 1);
        if (path == NULL)
                return -1;
        sprintf(path, "%s%s", PROCATTR, attr);

        fd = open(path, O_RDONLY);
        free(path);

        if (fd < 0)
                return -1;
        len = read(fd, value, size);

        close(fd);

        /* Ensure value is terminated */
        if (len <= 0 || len == size)
                return -1;
        value[len] = '\0';

        path = strchr(value, '\n');
        if (path)
                *path = '\0';

        return 0;
}

int read_sysfs_lsms(char *lsms, size_t size)
{
        FILE *fp;
        size_t red;

        fp = fopen("/sys/kernel/security/lsm", "r");
        if (fp == NULL)
                return -1;
        red = fread(lsms, 1, size, fp);
        fclose(fp);

        if (red <= 0 || red == size)
                return -1;
        lsms[red] = '\0';
        return 0;
}

int attr_lsm_count(void)
{
        char *names = calloc(sysconf(_SC_PAGESIZE), 1);
        int count = 0;

        if (!names)
                return 0;

        if (read_sysfs_lsms(names, sysconf(_SC_PAGESIZE)))
                return 0;

        if (strstr(names, "selinux"))
                count++;
        if (strstr(names, "smack"))
                count++;
        if (strstr(names, "apparmor"))
                count++;

        return count;
}