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"
28 #include <selinux/selinux.h>
29 #include <selinux/avc.h>
38 #include "selinux-util.h"
42 static bool initialized = false;
51 Any time an access gets denied this callback will be called
52 with the audit data. We then need to just copy the audit data into the msgbuf.
54 static int audit_callback(
60 const struct audit_info *audit = auditdata;
61 uid_t uid = 0, login_uid = 0;
63 char login_uid_buf[DECIMAL_STR_MAX(uid_t) + 1] = "n/a";
64 char uid_buf[DECIMAL_STR_MAX(uid_t) + 1] = "n/a";
65 char gid_buf[DECIMAL_STR_MAX(gid_t) + 1] = "n/a";
67 if (sd_bus_creds_get_audit_login_uid(audit->creds, &login_uid) >= 0)
68 xsprintf(login_uid_buf, UID_FMT, login_uid);
69 if (sd_bus_creds_get_euid(audit->creds, &uid) >= 0)
70 xsprintf(uid_buf, UID_FMT, uid);
71 if (sd_bus_creds_get_egid(audit->creds, &gid) >= 0)
72 xsprintf(gid_buf, GID_FMT, gid);
74 snprintf(msgbuf, msgbufsize,
75 "auid=%s uid=%s gid=%s%s%s%s%s%s%s",
76 login_uid_buf, uid_buf, gid_buf,
77 audit->path ? " path=\"" : "", strempty(audit->path), audit->path ? "\"" : "",
78 audit->cmdline ? " cmdline=\"" : "", strempty(audit->cmdline), audit->cmdline ? "\"" : "");
84 Any time an access gets denied this callback will be called
85 code copied from dbus. If audit is turned on the messages will go as
86 user_avc's into the /var/log/audit/audit.log, otherwise they will be
89 _printf_(2, 3) static int log_callback(int type, const char *fmt, ...) {
93 if (get_audit_fd() >= 0) {
94 _cleanup_free_ char *buf = NULL;
98 r = vasprintf(&buf, fmt, ap);
102 audit_log_user_avc_message(get_audit_fd(), AUDIT_USER_AVC, buf, NULL, NULL, NULL, 0);
109 log_internalv(LOG_AUTH | LOG_INFO, 0, __FILE__, __LINE__, __FUNCTION__, fmt, ap);
116 Function must be called once to initialize the SELinux AVC environment.
118 If you want to cleanup memory you should need to call selinux_access_finish.
120 static int access_init(void) {
123 if (avc_open(NULL, 0))
124 return log_error_errno(errno, "avc_open() failed: %m");
126 selinux_set_callback(SELINUX_CB_AUDIT, (union selinux_callback) audit_callback);
127 selinux_set_callback(SELINUX_CB_LOG, (union selinux_callback) log_callback);
129 if (security_getenforce() < 0){
137 static int mac_selinux_access_init(sd_bus_error *error) {
143 if (!mac_selinux_use())
148 return sd_bus_error_set(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to initialize SELinux.");
155 void mac_selinux_access_free(void) {
167 This function communicates with the kernel to check whether or not it should
169 If the machine is in permissive mode it will return ok. Audit messages will
170 still be generated if the access would be denied in enforcing mode.
172 int mac_selinux_generic_access_check(
173 sd_bus_message *message,
175 const char *permission,
176 sd_bus_error *error) {
179 _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
180 const char *tclass = NULL, *scon = NULL;
181 struct audit_info audit_info = {};
182 _cleanup_free_ char *cl = NULL;
183 security_context_t fcon = NULL;
184 char **cmdline = NULL;
191 if (!mac_selinux_use())
194 r = mac_selinux_access_init(error);
198 r = sd_bus_query_sender_creds(
200 SD_BUS_CREDS_PID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|
201 SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_AUDIT_LOGIN_UID|
202 SD_BUS_CREDS_SELINUX_CONTEXT|
203 SD_BUS_CREDS_AUGMENT /* get more bits from /proc */,
208 r = sd_bus_creds_get_selinux_context(creds, &scon);
213 /* Get the file context of the unit file */
215 r = getfilecon(path, &fcon);
217 r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get file context on %s.", path);
225 r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get current context.");
232 sd_bus_creds_get_cmdline(creds, &cmdline);
233 cl = strv_join(cmdline, " ");
235 audit_info.creds = creds;
236 audit_info.path = path;
237 audit_info.cmdline = cl;
239 r = selinux_check_access((security_context_t) scon, fcon, tclass, permission, &audit_info);
241 r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "SELinux policy denies access.");
243 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);
248 if (r < 0 && security_getenforce() != 1) {
249 sd_bus_error_free(error);
259 int mac_selinux_unit_access_check_strv(char **units,
260 sd_bus_message *message,
262 const char *permission,
263 sd_bus_error *error) {
269 STRV_FOREACH(i, units) {
270 u = manager_get_unit(m, *i);
272 r = mac_selinux_unit_access_check(u, message, permission, error);