1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
2 #include <unistd.h>
3 #include <sys/types.h>
4 #include <stdlib.h>
5 #include <errno.h>
6 #include "selinux_internal.h"
7 #include <selinux/avc.h>
8 #include "avc_internal.h"
9
10 static pthread_once_t once = PTHREAD_ONCE_INIT;
11 static int selinux_enabled;
12
avc_reset_callback(uint32_t event,security_id_t ssid,security_id_t tsid,security_class_t tclass,access_vector_t perms,access_vector_t * out_retained)13 static int avc_reset_callback(uint32_t event __attribute__((unused)),
14 security_id_t ssid __attribute__((unused)),
15 security_id_t tsid __attribute__((unused)),
16 security_class_t tclass __attribute__((unused)),
17 access_vector_t perms __attribute__((unused)),
18 access_vector_t *out_retained __attribute__((unused)))
19 {
20 flush_class_cache();
21 return 0;
22 }
23
avc_init_once(void)24 static void avc_init_once(void)
25 {
26 selinux_enabled = is_selinux_enabled();
27 if (selinux_enabled == 1) {
28 if (avc_open(NULL, 0))
29 return;
30 avc_add_callback(avc_reset_callback, AVC_CALLBACK_RESET,
31 0, 0, 0, 0);
32 }
33 }
34
selinux_check_access(const char * scon,const char * tcon,const char * class,const char * perm,void * aux)35 int selinux_check_access(const char *scon, const char *tcon, const char *class, const char *perm, void *aux) {
36 int rc;
37 security_id_t scon_id;
38 security_id_t tcon_id;
39 security_class_t sclass;
40 access_vector_t av;
41
42 __selinux_once(once, avc_init_once);
43
44 if (selinux_enabled != 1)
45 return 0;
46
47 rc = avc_context_to_sid(scon, &scon_id);
48 if (rc < 0)
49 return rc;
50
51 rc = avc_context_to_sid(tcon, &tcon_id);
52 if (rc < 0)
53 return rc;
54
55 (void) avc_netlink_check_nb();
56
57 sclass = string_to_security_class(class);
58 if (sclass == 0) {
59 rc = errno;
60 avc_log(SELINUX_ERROR, "Unknown class %s", class);
61 if (security_deny_unknown() == 0)
62 return 0;
63 errno = rc;
64 return -1;
65 }
66
67 av = string_to_av_perm(sclass, perm);
68 if (av == 0) {
69 rc = errno;
70 avc_log(SELINUX_ERROR, "Unknown permission %s for class %s", perm, class);
71 if (security_deny_unknown() == 0)
72 return 0;
73 errno = rc;
74 return -1;
75 }
76
77 return avc_has_perm (scon_id, tcon_id, sclass, av, NULL, aux);
78 }
79
selinux_check_passwd_access(access_vector_t requested)80 int selinux_check_passwd_access(access_vector_t requested)
81 {
82 int status = -1;
83 char *user_context;
84 if (is_selinux_enabled() == 0)
85 return 0;
86 if (getprevcon_raw(&user_context) == 0) {
87 security_class_t passwd_class;
88 struct av_decision avd;
89 int retval;
90
91 passwd_class = string_to_security_class("passwd");
92 if (passwd_class == 0) {
93 freecon(user_context);
94 return 0;
95 }
96
97 retval = security_compute_av_raw(user_context,
98 user_context,
99 passwd_class,
100 requested,
101 &avd);
102
103 if ((retval == 0) && ((requested & avd.allowed) == requested)) {
104 status = 0;
105 }
106 freecon(user_context);
107 }
108
109 if (status != 0 && security_getenforce() == 0)
110 status = 0;
111
112 return status;
113 }
114
hidden_def(selinux_check_passwd_access)115 hidden_def(selinux_check_passwd_access)
116
117 int checkPasswdAccess(access_vector_t requested)
118 {
119 return selinux_check_passwd_access(requested);
120 }
121