1 #include <unistd.h>
2 #include <sys/types.h>
3 #include <fcntl.h>
4 #include <stdlib.h>
5 #include <stdio.h>
6 #include <errno.h>
7 #include <string.h>
8 #include <limits.h>
9 #include "selinux_internal.h"
10 #include "policy.h"
11 #include "mapping.h"
12 
security_compute_av(const char * scon,const char * tcon,security_class_t tclass,access_vector_t requested,struct av_decision * avd)13 int security_compute_av(const char * scon,
14 			const char * tcon,
15 			security_class_t tclass,
16 			access_vector_t requested,
17 			struct av_decision *avd)
18 {
19 	char path[PATH_MAX];
20 	char *buf;
21 	size_t len;
22 	int fd, ret;
23 
24 	if (!selinux_mnt) {
25 		errno = ENOENT;
26 		return -1;
27 	}
28 
29 	snprintf(path, sizeof path, "%s/access", selinux_mnt);
30 	fd = open(path, O_RDWR);
31 	if (fd < 0)
32 		return -1;
33 
34 	len = selinux_page_size;
35 	buf = malloc(len);
36 	if (!buf) {
37 		ret = -1;
38 		goto out;
39 	}
40 
41 	snprintf(buf, len, "%s %s %hu %x", scon, tcon,
42 		 unmap_class(tclass), unmap_perm(tclass, requested));
43 
44 	ret = write(fd, buf, strlen(buf));
45 	if (ret < 0)
46 		goto out2;
47 
48 	memset(buf, 0, len);
49 	ret = read(fd, buf, len - 1);
50 	if (ret < 0)
51 		goto out2;
52 
53 	ret = sscanf(buf, "%x %x %x %x %u %x",
54 		     &avd->allowed, &avd->decided,
55 		     &avd->auditallow, &avd->auditdeny,
56 		     &avd->seqno, &avd->flags);
57 	if (ret < 5) {
58 		ret = -1;
59 		goto out2;
60 	} else if (ret < 6)
61 		avd->flags = 0;
62 
63 	map_decision(tclass, avd);
64 
65 	ret = 0;
66       out2:
67 	free(buf);
68       out:
69 	close(fd);
70 	return ret;
71 }
72 
73