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) + 1] = "n/a";
68 char uid_buf[DECIMAL_STR_MAX(uid_t) + 1] = "n/a";
69 char gid_buf[DECIMAL_STR_MAX(gid_t) + 1] = "n/a";
71 if (sd_bus_creds_get_audit_login_uid(audit->creds, &login_uid) >= 0)
72 xsprintf(login_uid_buf, UID_FMT, login_uid);
73 if (sd_bus_creds_get_euid(audit->creds, &uid) >= 0)
74 xsprintf(uid_buf, UID_FMT, uid);
75 if (sd_bus_creds_get_egid(audit->creds, &gid) >= 0)
76 xsprintf(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 ? "\"" : "");
88 Any time an access gets denied this callback will be called
89 code copied from dbus. If audit is turned on the messages will go as
90 user_avc's into the /var/log/audit/audit.log, otherwise they will be
93 _printf_(2, 3) static int log_callback(int type, const char *fmt, ...) {
97 if (get_audit_fd() >= 0) {
98 _cleanup_free_ char *buf = NULL;
102 r = vasprintf(&buf, fmt, ap);
106 audit_log_user_avc_message(get_audit_fd(), AUDIT_USER_AVC, buf, NULL, NULL, NULL, 0);
113 log_internalv(LOG_AUTH | LOG_INFO, 0, __FILE__, __LINE__, __FUNCTION__, fmt, ap);
120 Function must be called once to initialize the SELinux AVC environment.
122 If you want to cleanup memory you should need to call selinux_access_finish.
124 static int access_init(void) {
127 if (avc_open(NULL, 0))
128 return log_error_errno(errno, "avc_open() failed: %m");
130 selinux_set_callback(SELINUX_CB_AUDIT, (union selinux_callback) audit_callback);
131 selinux_set_callback(SELINUX_CB_LOG, (union selinux_callback) log_callback);
133 if (security_getenforce() < 0){
141 static int mac_selinux_access_init(sd_bus_error *error) {
147 if (!mac_selinux_use())
152 return sd_bus_error_set(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to initialize SELinux.");
159 void mac_selinux_access_free(void) {
171 This function communicates with the kernel to check whether or not it should
173 If the machine is in permissive mode it will return ok. Audit messages will
174 still be generated if the access would be denied in enforcing mode.
176 int mac_selinux_generic_access_check(
177 sd_bus_message *message,
179 const char *permission,
180 sd_bus_error *error) {
183 _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
184 const char *tclass = NULL, *scon = NULL;
185 struct audit_info audit_info = {};
186 _cleanup_free_ char *cl = NULL;
187 security_context_t fcon = NULL;
188 char **cmdline = NULL;
195 if (!mac_selinux_use())
198 r = mac_selinux_access_init(error);
202 r = sd_bus_query_sender_creds(
204 SD_BUS_CREDS_PID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|
205 SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_AUDIT_LOGIN_UID|
206 SD_BUS_CREDS_SELINUX_CONTEXT|
207 SD_BUS_CREDS_AUGMENT /* get more bits from /proc */,
212 r = sd_bus_creds_get_selinux_context(creds, &scon);
217 /* Get the file context of the unit file */
219 r = getfilecon(path, &fcon);
221 r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get file context on %s.", path);
229 r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get current context.");
236 sd_bus_creds_get_cmdline(creds, &cmdline);
237 cl = strv_join(cmdline, " ");
239 audit_info.creds = creds;
240 audit_info.path = path;
241 audit_info.cmdline = cl;
243 r = selinux_check_access((security_context_t) scon, fcon, tclass, permission, &audit_info);
245 r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "SELinux policy denies access.");
247 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);
252 if (r < 0 && security_getenforce() != 1) {
253 sd_bus_error_free(error);
263 int mac_selinux_unit_access_check_strv(char **units,
264 sd_bus_message *message,
266 const char *permission,
267 sd_bus_error *error) {
273 STRV_FOREACH(i, units) {
274 u = manager_get_unit(m, *i);
276 r = mac_selinux_unit_access_check(u, message, permission, error);