2 Unix SMB/CIFS implementation.
3 Copyright (C) Jeremy Allison 1998.
4 rewritten for version 2.0.6 by Tridge
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
22 #include "system/passwd.h" /* uid_wrapper */
24 /* we are running this code in autoconf test mode to see which type of setuid
26 #if defined(HAVE_UNISTD_H)
31 #include <sys/types.h>
34 #ifdef HAVE_SYS_PRIV_H
41 #define DEBUG(x, y) printf y
42 #define smb_panic(x) exit(1)
46 /* are we running as non-root? This is used by the regresison test code,
47 and potentially also for sites that want non-root smbd */
48 static uid_t initial_uid;
49 static gid_t initial_gid;
51 /****************************************************************************
52 remember what uid we got started as - this allows us to run correctly
53 as non-root while catching trapdoor systems
54 ****************************************************************************/
58 static int initialized;
61 initial_uid = geteuid();
62 initial_gid = getegid();
67 /****************************************************************************
68 some code (eg. winbindd) needs to know what uid we started as
69 ****************************************************************************/
70 uid_t sec_initial_uid(void)
75 /****************************************************************************
76 some code (eg. winbindd, profiling shm) needs to know what gid we started as
77 ****************************************************************************/
78 gid_t sec_initial_gid(void)
83 /****************************************************************************
84 are we running in non-root mode?
85 ****************************************************************************/
86 bool non_root_mode(void)
88 return (initial_uid != (uid_t)0);
91 /****************************************************************************
92 abort if we haven't set the uid correctly
93 ****************************************************************************/
94 static void assert_uid(uid_t ruid, uid_t euid)
96 if ((euid != (uid_t)-1 && geteuid() != euid) ||
97 (ruid != (uid_t)-1 && getuid() != ruid)) {
98 if (!non_root_mode()) {
99 DEBUG(0,("Failed to set uid privileges to (%d,%d) now set to (%d,%d)\n",
100 (int)ruid, (int)euid,
101 (int)getuid(), (int)geteuid()));
102 smb_panic("failed to set uid\n");
108 /****************************************************************************
109 abort if we haven't set the gid correctly
110 ****************************************************************************/
111 static void assert_gid(gid_t rgid, gid_t egid)
113 if ((egid != (gid_t)-1 && getegid() != egid) ||
114 (rgid != (gid_t)-1 && getgid() != rgid)) {
115 if (!non_root_mode()) {
116 DEBUG(0,("Failed to set gid privileges to (%d,%d) now set to (%d,%d) uid=(%d,%d)\n",
117 (int)rgid, (int)egid,
118 (int)getgid(), (int)getegid(),
119 (int)getuid(), (int)geteuid()));
120 smb_panic("failed to set gid\n");
126 /****************************************************************************
127 Gain root privilege before doing something.
128 We want to end up with ruid==euid==0
129 ****************************************************************************/
130 void gain_root_privilege(void)
145 setuidx(ID_EFFECTIVE, 0);
149 /* this is needed on some systems */
156 /****************************************************************************
157 Ensure our real and effective groups are zero.
158 we want to end up with rgid==egid==0
159 ****************************************************************************/
160 void gain_root_group_privilege(void)
175 setgidx(ID_EFFECTIVE, 0);
185 /****************************************************************************
186 Set effective uid, and possibly the real uid too.
187 We want to end up with either:
189 ruid==uid and euid==uid
193 ruid==0 and euid==uid
195 depending on what the local OS will allow us to regain root from.
196 ****************************************************************************/
197 void set_effective_uid(uid_t uid)
200 /* Set the effective as well as the real uid. */
201 if (setresuid(uid,uid,-1) == -1) {
202 if (errno == EAGAIN) {
203 DEBUG(0, ("setresuid failed with EAGAIN. uid(%d) "
204 "might be over its NPROC limit\n",
219 setuidx(ID_EFFECTIVE, uid);
225 /****************************************************************************
226 Set *only* the effective gid.
227 we want to end up with rgid==0 and egid==gid
228 ****************************************************************************/
229 void set_effective_gid(gid_t gid)
232 setresgid(-1,gid,-1);
244 setgidx(ID_EFFECTIVE, gid);
250 static uid_t saved_euid, saved_ruid;
251 static gid_t saved_egid, saved_rgid;
253 /****************************************************************************
254 save the real and effective uid for later restoration. Used by the quotas
256 ****************************************************************************/
257 void save_re_uid(void)
259 saved_ruid = getuid();
260 saved_euid = geteuid();
264 /****************************************************************************
266 ****************************************************************************/
268 void restore_re_uid_fromroot(void)
271 setresuid(saved_ruid, saved_euid, -1);
273 setreuid(saved_ruid, -1);
274 setreuid(-1,saved_euid);
276 setuidx(ID_REAL, saved_ruid);
277 setuidx(ID_EFFECTIVE, saved_euid);
279 set_effective_uid(saved_euid);
280 if (getuid() != saved_ruid)
282 set_effective_uid(saved_euid);
285 assert_uid(saved_ruid, saved_euid);
288 void restore_re_uid(void)
290 set_effective_uid(0);
291 restore_re_uid_fromroot();
294 /****************************************************************************
295 save the real and effective gid for later restoration. Used by the
297 ****************************************************************************/
298 void save_re_gid(void)
300 saved_rgid = getgid();
301 saved_egid = getegid();
304 /****************************************************************************
306 ****************************************************************************/
307 void restore_re_gid(void)
310 setresgid(saved_rgid, saved_egid, -1);
312 setregid(saved_rgid, -1);
313 setregid(-1,saved_egid);
315 setgidx(ID_REAL, saved_rgid);
316 setgidx(ID_EFFECTIVE, saved_egid);
318 set_effective_gid(saved_egid);
319 if (getgid() != saved_rgid)
321 set_effective_gid(saved_egid);
324 assert_gid(saved_rgid, saved_egid);
328 /****************************************************************************
329 set the real AND effective uid to the current effective uid in a way that
330 allows root to be regained.
331 This is only possible on some platforms.
332 ****************************************************************************/
335 uid_t uid = geteuid();
338 setresuid(geteuid(), -1, -1);
357 assert_uid(uid, uid);
362 /****************************************************************************
363 Become the specified uid and gid - permanently !
364 there should be no way back if possible
365 ****************************************************************************/
366 void become_user_permanently(uid_t uid, gid_t gid)
369 * First - gain root privilege. We do this to ensure
370 * we can lose it again.
373 gain_root_privilege();
374 gain_root_group_privilege();
377 setresgid(gid,gid,gid);
379 setresuid(uid,uid,uid);
399 setgidx(ID_REAL, gid);
400 setgidx(ID_EFFECTIVE, gid);
402 setuidx(ID_REAL, uid);
403 setuidx(ID_EFFECTIVE, uid);
407 assert_uid(uid, uid);
408 assert_gid(gid, gid);
413 /****************************************************************************
414 this function just checks that we don't get ENOSYS back
415 ****************************************************************************/
416 static int have_syscall(void)
433 setuidx(ID_EFFECTIVE, -1);
436 if (errno == ENOSYS) return -1;
444 #if (defined(AIX) && defined(USE_SETREUID))
445 /* setreuid is badly broken on AIX 4.1, we avoid it completely */
446 fprintf(stderr,"avoiding possibly broken setreuid\n");
450 /* if not running as root then at least check to see if we get ENOSYS - this
451 handles Linux 2.0.x with glibc 2.1 */
452 fprintf(stderr,"not running as root: checking for ENOSYS\n");
453 exit(have_syscall());
456 gain_root_privilege();
457 gain_root_group_privilege();
458 set_effective_gid(1);
459 set_effective_uid(1);
462 gain_root_privilege();
463 gain_root_group_privilege();
464 become_user_permanently(1, 1);
467 fprintf(stderr,"uid not set permanently\n");
477 /****************************************************************************
478 Check if we are setuid root. Used in libsmb and smbpasswd paranoia checks.
479 ****************************************************************************/
480 bool is_setuid_root(void)
482 return (geteuid() == (uid_t)0) && (getuid() != (uid_t)0);