1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2012 Dan Walsh
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include "selinux-access.h"
30 #include <selinux/selinux.h>
31 #include <selinux/avc.h>
32 #include <sys/socket.h>
42 #include "selinux-util.h"
46 static bool initialized = false;
55 Any time an access gets denied this callback will be called
56 with the audit data. We then need to just copy the audit data into the msgbuf.
58 static int audit_callback(
64 const struct audit_info *audit = auditdata;
65 uid_t uid = 0, login_uid = 0;
67 char login_uid_buf[DECIMAL_STR_MAX(uid_t)] = "n/a";
68 char uid_buf[DECIMAL_STR_MAX(uid_t)] = "n/a";
69 char gid_buf[DECIMAL_STR_MAX(gid_t)] = "n/a";
71 if (sd_bus_creds_get_audit_login_uid(audit->creds, &login_uid) >= 0)
72 snprintf(login_uid_buf, sizeof(login_uid_buf), UID_FMT, login_uid);
73 if (sd_bus_creds_get_uid(audit->creds, &uid) >= 0)
74 snprintf(uid_buf, sizeof(uid_buf), UID_FMT, uid);
75 if (sd_bus_creds_get_gid(audit->creds, &gid) >= 0)
76 snprintf(gid_buf, sizeof(gid_buf), GID_FMT, gid);
78 snprintf(msgbuf, msgbufsize,
79 "auid=%s uid=%s gid=%s%s%s%s%s%s%s",
80 login_uid_buf, uid_buf, gid_buf,
81 audit->path ? " path=\"" : "", strempty(audit->path), audit->path ? "\"" : "",
82 audit->cmdline ? " cmdline=\"" : "", strempty(audit->cmdline), audit->cmdline ? "\"" : "");
84 msgbuf[msgbufsize-1] = 0;
90 Any time an access gets denied this callback will be called
91 code copied from dbus. If audit is turned on the messages will go as
92 user_avc's into the /var/log/audit/audit.log, otherwise they will be
95 _printf_(2, 3) static int log_callback(int type, const char *fmt, ...) {
99 if (get_audit_fd() >= 0) {
100 _cleanup_free_ char *buf = NULL;
104 r = vasprintf(&buf, fmt, ap);
108 audit_log_user_avc_message(get_audit_fd(), AUDIT_USER_AVC, buf, NULL, NULL, NULL, 0);
115 log_internalv(LOG_AUTH | LOG_INFO, 0, __FILE__, __LINE__, __FUNCTION__, fmt, ap);
122 Function must be called once to initialize the SELinux AVC environment.
124 If you want to cleanup memory you should need to call selinux_access_finish.
126 static int access_init(void) {
129 if (avc_open(NULL, 0))
130 return log_error_errno(errno, "avc_open() failed: %m");
132 selinux_set_callback(SELINUX_CB_AUDIT, (union selinux_callback) audit_callback);
133 selinux_set_callback(SELINUX_CB_LOG, (union selinux_callback) log_callback);
135 if (security_getenforce() < 0){
143 static int mac_selinux_access_init(sd_bus_error *error) {
149 if (!mac_selinux_use())
154 return sd_bus_error_set(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to initialize SELinux.");
161 void mac_selinux_access_free(void) {
173 This function communicates with the kernel to check whether or not it should
175 If the machine is in permissive mode it will return ok. Audit messages will
176 still be generated if the access would be denied in enforcing mode.
178 int mac_selinux_generic_access_check(
179 sd_bus_message *message,
181 const char *permission,
182 sd_bus_error *error) {
185 _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
186 const char *tclass = NULL, *scon = NULL;
187 struct audit_info audit_info = {};
188 _cleanup_free_ char *cl = NULL;
189 security_context_t fcon = NULL;
190 char **cmdline = NULL;
197 if (!mac_selinux_use())
200 r = mac_selinux_access_init(error);
204 r = sd_bus_query_sender_creds(
206 SD_BUS_CREDS_PID|SD_BUS_CREDS_UID|SD_BUS_CREDS_GID|
207 SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_AUDIT_LOGIN_UID|
208 SD_BUS_CREDS_SELINUX_CONTEXT|
209 SD_BUS_CREDS_AUGMENT /* get more bits from /proc */,
214 r = sd_bus_creds_get_selinux_context(creds, &scon);
219 /* Get the file context of the unit file */
221 r = getfilecon(path, &fcon);
223 r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get file context on %s.", path);
231 r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get current context.");
238 sd_bus_creds_get_cmdline(creds, &cmdline);
239 cl = strv_join(cmdline, " ");
241 audit_info.creds = creds;
242 audit_info.path = path;
243 audit_info.cmdline = cl;
245 r = selinux_check_access((security_context_t) scon, fcon, tclass, permission, &audit_info);
247 r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "SELinux policy denies access.");
249 log_debug("SELinux access check scon=%s tcon=%s tclass=%s perm=%s path=%s cmdline=%s: %i", scon, fcon, tclass, permission, path, cl, r);
254 if (r < 0 && security_getenforce() != 1) {
255 sd_bus_error_free(error);
265 int mac_selinux_unit_access_check_strv(char **units,
266 sd_bus_message *message,
268 const char *permission,
269 sd_bus_error *error) {
275 STRV_FOREACH(i, units) {
276 u = manager_get_unit(m, *i);
278 r = mac_selinux_unit_access_check(u, message, permission, error);