1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Linux Security Module infrastructure tests
 4 *
 5 * Copyright © 2023 Casey Schaufler <casey@schaufler-ca.com>
 6 */
 7
 8#define _GNU_SOURCE
 9#include <linux/lsm.h>
10#include <fcntl.h>
11#include <string.h>
12#include <stdio.h>
13#include <stdlib.h>
14#include <unistd.h>
15#include <sys/types.h>
16#include "common.h"
17
18#define PROCATTR "/proc/self/attr/"
19
20int read_proc_attr(const char *attr, char *value, size_t size)
21{
22	int fd;
23	int len;
24	char *path;
25
26	len = strlen(PROCATTR) + strlen(attr) + 1;
27	path = calloc(len, 1);
28	if (path == NULL)
29		return -1;
30	sprintf(path, "%s%s", PROCATTR, attr);
31
32	fd = open(path, O_RDONLY);
33	free(path);
34
35	if (fd < 0)
36		return -1;
37	len = read(fd, value, size);
38
39	close(fd);
40
41	/* Ensure value is terminated */
42	if (len <= 0 || len == size)
43		return -1;
44	value[len] = '\0';
45
46	path = strchr(value, '\n');
47	if (path)
48		*path = '\0';
49
50	return 0;
51}
52
53int read_sysfs_lsms(char *lsms, size_t size)
54{
55	FILE *fp;
56	size_t red;
57
58	fp = fopen("/sys/kernel/security/lsm", "r");
59	if (fp == NULL)
60		return -1;
61	red = fread(lsms, 1, size, fp);
62	fclose(fp);
63
64	if (red <= 0 || red == size)
65		return -1;
66	lsms[red] = '\0';
67	return 0;
68}
69
70int attr_lsm_count(void)
71{
72	char *names = calloc(sysconf(_SC_PAGESIZE), 1);
73	int count = 0;
74
75	if (!names)
76		return 0;
77
78	if (read_sysfs_lsms(names, sysconf(_SC_PAGESIZE)))
79		return 0;
80
81	if (strstr(names, "selinux"))
82		count++;
83	if (strstr(names, "smack"))
84		count++;
85	if (strstr(names, "apparmor"))
86		count++;
87
88	return count;
89}