source: vendor/3.5.0/source3/lib/util_sec.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 15 years ago

Samba 3.5.0: Initial import
File size: 11.2 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3 Copyright (C) Jeremy Allison 1998.
4 rewritten for version 2.0.6 by Tridge
5
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.
10
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.
15
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/>.
18*/
19
20#ifndef AUTOCONF_TEST
21#include "includes.h"
22#else
23/* we are running this code in autoconf test mode to see which type of setuid
24 function works */
25#if defined(HAVE_UNISTD_H)
26#include <unistd.h>
27#endif
28#include <stdlib.h>
29#include <stdio.h>
30#include <sys/types.h>
31#include <errno.h>
32
33#ifdef HAVE_SYS_PRIV_H
34#include <sys/priv.h>
35#endif
36#ifdef HAVE_SYS_ID_H
37#include <sys/id.h>
38#endif
39
40#define DEBUG(x, y) printf y
41#define smb_panic(x) exit(1)
42#define bool int
43#endif
44
45/* are we running as non-root? This is used by the regresison test code,
46 and potentially also for sites that want non-root smbd */
47static uid_t initial_uid;
48static gid_t initial_gid;
49
50/****************************************************************************
51remember what uid we got started as - this allows us to run correctly
52as non-root while catching trapdoor systems
53****************************************************************************/
54
55void sec_init(void)
56{
57 static int initialized;
58
59 if (!initialized) {
60 initial_uid = geteuid();
61 initial_gid = getegid();
62 initialized = 1;
63 }
64}
65
66/****************************************************************************
67some code (eg. winbindd) needs to know what uid we started as
68****************************************************************************/
69uid_t sec_initial_uid(void)
70{
71 return initial_uid;
72}
73
74/****************************************************************************
75some code (eg. winbindd, profiling shm) needs to know what gid we started as
76****************************************************************************/
77gid_t sec_initial_gid(void)
78{
79 return initial_gid;
80}
81
82/****************************************************************************
83are we running in non-root mode?
84****************************************************************************/
85bool non_root_mode(void)
86{
87 return (initial_uid != (uid_t)0);
88}
89
90/****************************************************************************
91abort if we haven't set the uid correctly
92****************************************************************************/
93static void assert_uid(uid_t ruid, uid_t euid)
94{
95 if ((euid != (uid_t)-1 && geteuid() != euid) ||
96 (ruid != (uid_t)-1 && getuid() != ruid)) {
97 if (!non_root_mode()) {
98 DEBUG(0,("Failed to set uid privileges to (%d,%d) now set to (%d,%d)\n",
99 (int)ruid, (int)euid,
100 (int)getuid(), (int)geteuid()));
101 smb_panic("failed to set uid\n");
102 exit(1);
103 }
104 }
105}
106
107/****************************************************************************
108abort if we haven't set the gid correctly
109****************************************************************************/
110static void assert_gid(gid_t rgid, gid_t egid)
111{
112 if ((egid != (gid_t)-1 && getegid() != egid) ||
113 (rgid != (gid_t)-1 && getgid() != rgid)) {
114 if (!non_root_mode()) {
115 DEBUG(0,("Failed to set gid privileges to (%d,%d) now set to (%d,%d) uid=(%d,%d)\n",
116 (int)rgid, (int)egid,
117 (int)getgid(), (int)getegid(),
118 (int)getuid(), (int)geteuid()));
119 smb_panic("failed to set gid\n");
120 exit(1);
121 }
122 }
123}
124
125/****************************************************************************
126 Gain root privilege before doing something.
127 We want to end up with ruid==euid==0
128****************************************************************************/
129void gain_root_privilege(void)
130{
131#if USE_SETRESUID
132 setresuid(0,0,0);
133#endif
134
135#if USE_SETEUID
136 seteuid(0);
137#endif
138
139#if USE_SETREUID
140 setreuid(0, 0);
141#endif
142
143#if USE_SETUIDX
144 setuidx(ID_EFFECTIVE, 0);
145 setuidx(ID_REAL, 0);
146#endif
147
148 /* this is needed on some systems */
149 setuid(0);
150
151 assert_uid(0, 0);
152}
153
154
155/****************************************************************************
156 Ensure our real and effective groups are zero.
157 we want to end up with rgid==egid==0
158****************************************************************************/
159void gain_root_group_privilege(void)
160{
161#if USE_SETRESUID
162 setresgid(0,0,0);
163#endif
164
165#if USE_SETREUID
166 setregid(0,0);
167#endif
168
169#if USE_SETEUID
170 setegid(0);
171#endif
172
173#if USE_SETUIDX
174 setgidx(ID_EFFECTIVE, 0);
175 setgidx(ID_REAL, 0);
176#endif
177
178 setgid(0);
179
180 assert_gid(0, 0);
181}
182
183
184/****************************************************************************
185 Set effective uid, and possibly the real uid too.
186 We want to end up with either:
187
188 ruid==uid and euid==uid
189
190 or
191
192 ruid==0 and euid==uid
193
194 depending on what the local OS will allow us to regain root from.
195****************************************************************************/
196void set_effective_uid(uid_t uid)
197{
198#if USE_SETRESUID
199 /* Set the effective as well as the real uid. */
200 if (setresuid(uid,uid,-1) == -1) {
201 if (errno == EAGAIN) {
202 DEBUG(0, ("setresuid failed with EAGAIN. uid(%d) "
203 "might be over its NPROC limit\n",
204 (int)uid));
205 }
206 }
207#endif
208
209#if USE_SETREUID
210 setreuid(-1,uid);
211#endif
212
213#if USE_SETEUID
214 seteuid(uid);
215#endif
216
217#if USE_SETUIDX
218 setuidx(ID_EFFECTIVE, uid);
219#endif
220
221 assert_uid(-1, uid);
222}
223
224/****************************************************************************
225 Set *only* the effective gid.
226 we want to end up with rgid==0 and egid==gid
227****************************************************************************/
228void set_effective_gid(gid_t gid)
229{
230#if USE_SETRESUID
231 setresgid(-1,gid,-1);
232#endif
233
234#if USE_SETREUID
235 setregid(-1,gid);
236#endif
237
238#if USE_SETEUID
239 setegid(gid);
240#endif
241
242#if USE_SETUIDX
243 setgidx(ID_EFFECTIVE, gid);
244#endif
245
246 assert_gid(-1, gid);
247}
248
249static uid_t saved_euid, saved_ruid;
250static gid_t saved_egid, saved_rgid;
251
252/****************************************************************************
253 save the real and effective uid for later restoration. Used by the quotas
254 code
255****************************************************************************/
256void save_re_uid(void)
257{
258 saved_ruid = getuid();
259 saved_euid = geteuid();
260}
261
262
263/****************************************************************************
264 and restore them!
265****************************************************************************/
266
267void restore_re_uid_fromroot(void)
268{
269#if USE_SETRESUID
270 setresuid(saved_ruid, saved_euid, -1);
271#elif USE_SETREUID
272 setreuid(saved_ruid, -1);
273 setreuid(-1,saved_euid);
274#elif USE_SETUIDX
275 setuidx(ID_REAL, saved_ruid);
276 setuidx(ID_EFFECTIVE, saved_euid);
277#else
278 set_effective_uid(saved_euid);
279 if (getuid() != saved_ruid)
280 setuid(saved_ruid);
281 set_effective_uid(saved_euid);
282#endif
283
284 assert_uid(saved_ruid, saved_euid);
285}
286
287void restore_re_uid(void)
288{
289 set_effective_uid(0);
290 restore_re_uid_fromroot();
291}
292
293/****************************************************************************
294 save the real and effective gid for later restoration. Used by the
295 getgroups code
296****************************************************************************/
297void save_re_gid(void)
298{
299 saved_rgid = getgid();
300 saved_egid = getegid();
301}
302
303/****************************************************************************
304 and restore them!
305****************************************************************************/
306void restore_re_gid(void)
307{
308#if USE_SETRESUID
309 setresgid(saved_rgid, saved_egid, -1);
310#elif USE_SETREUID
311 setregid(saved_rgid, -1);
312 setregid(-1,saved_egid);
313#elif USE_SETUIDX
314 setgidx(ID_REAL, saved_rgid);
315 setgidx(ID_EFFECTIVE, saved_egid);
316#else
317 set_effective_gid(saved_egid);
318 if (getgid() != saved_rgid)
319 setgid(saved_rgid);
320 set_effective_gid(saved_egid);
321#endif
322
323 assert_gid(saved_rgid, saved_egid);
324}
325
326
327/****************************************************************************
328 set the real AND effective uid to the current effective uid in a way that
329 allows root to be regained.
330 This is only possible on some platforms.
331****************************************************************************/
332int set_re_uid(void)
333{
334 uid_t uid = geteuid();
335
336#if USE_SETRESUID
337 setresuid(geteuid(), -1, -1);
338#endif
339
340#if USE_SETREUID
341 setreuid(0, 0);
342 setreuid(uid, -1);
343 setreuid(-1, uid);
344#endif
345
346#if USE_SETEUID
347 /* can't be done */
348 return -1;
349#endif
350
351#if USE_SETUIDX
352 /* can't be done */
353 return -1;
354#endif
355
356 assert_uid(uid, uid);
357 return 0;
358}
359
360
361/****************************************************************************
362 Become the specified uid and gid - permanently !
363 there should be no way back if possible
364****************************************************************************/
365void become_user_permanently(uid_t uid, gid_t gid)
366{
367 /*
368 * First - gain root privilege. We do this to ensure
369 * we can lose it again.
370 */
371
372 gain_root_privilege();
373 gain_root_group_privilege();
374
375#if USE_SETRESUID
376 setresgid(gid,gid,gid);
377 setgid(gid);
378 setresuid(uid,uid,uid);
379 setuid(uid);
380#endif
381
382#if USE_SETREUID
383 setregid(gid,gid);
384 setgid(gid);
385 setreuid(uid,uid);
386 setuid(uid);
387#endif
388
389#if USE_SETEUID
390 setegid(gid);
391 setgid(gid);
392 setuid(uid);
393 seteuid(uid);
394 setuid(uid);
395#endif
396
397#if USE_SETUIDX
398 setgidx(ID_REAL, gid);
399 setgidx(ID_EFFECTIVE, gid);
400 setgid(gid);
401 setuidx(ID_REAL, uid);
402 setuidx(ID_EFFECTIVE, uid);
403 setuid(uid);
404#endif
405
406 assert_uid(uid, uid);
407 assert_gid(gid, gid);
408}
409
410#ifdef AUTOCONF_TEST
411
412/****************************************************************************
413this function just checks that we don't get ENOSYS back
414****************************************************************************/
415static int have_syscall(void)
416{
417 errno = 0;
418
419#if USE_SETRESUID
420 setresuid(-1,-1,-1);
421#endif
422
423#if USE_SETREUID
424 setreuid(-1,-1);
425#endif
426
427#if USE_SETEUID
428 seteuid(-1);
429#endif
430
431#if USE_SETUIDX
432 setuidx(ID_EFFECTIVE, -1);
433#endif
434
435 if (errno == ENOSYS) return -1;
436
437 return 0;
438}
439
440main()
441{
442 if (getuid() != 0) {
443#if (defined(AIX) && defined(USE_SETREUID))
444 /* setreuid is badly broken on AIX 4.1, we avoid it completely */
445 fprintf(stderr,"avoiding possibly broken setreuid\n");
446 exit(1);
447#endif
448
449 /* if not running as root then at least check to see if we get ENOSYS - this
450 handles Linux 2.0.x with glibc 2.1 */
451 fprintf(stderr,"not running as root: checking for ENOSYS\n");
452 exit(have_syscall());
453 }
454
455 gain_root_privilege();
456 gain_root_group_privilege();
457 set_effective_gid(1);
458 set_effective_uid(1);
459 save_re_uid();
460 restore_re_uid();
461 gain_root_privilege();
462 gain_root_group_privilege();
463 become_user_permanently(1, 1);
464 setuid(0);
465 if (getuid() == 0) {
466 fprintf(stderr,"uid not set permanently\n");
467 exit(1);
468 }
469
470 printf("OK\n");
471
472 exit(0);
473}
474#endif
475
476/****************************************************************************
477Check if we are setuid root. Used in libsmb and smbpasswd paranoia checks.
478****************************************************************************/
479bool is_setuid_root(void)
480{
481 return (geteuid() == (uid_t)0) && (getuid() != (uid_t)0);
482}
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