s3:smbd: s/struct timed_event/struct tevent_timer
[Samba/gebeck_regimport.git] / source3 / smbd / sec_ctx.c
blobd474219eba29ee4fed7a6f7d712bc48234eeefdc
1 /*
2 Unix SMB/CIFS implementation.
3 uid/user handling
4 Copyright (C) Tim Potter 2000
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/>.
20 #include "includes.h"
21 #include "system/passwd.h"
22 #include "smbd/smbd.h"
23 #include "smbd/globals.h"
24 #include "libcli/security/security_token.h"
25 #include "auth.h"
26 #include "smbprofile.h"
27 #include "../lib/util/setid.h"
29 extern struct current_user current_user;
31 /****************************************************************************
32 Are two UNIX tokens equal ?
33 ****************************************************************************/
35 bool unix_token_equal(const struct security_unix_token *t1, const struct security_unix_token *t2)
37 if (t1->uid != t2->uid || t1->gid != t2->gid ||
38 t1->ngroups != t2->ngroups) {
39 return false;
41 if (memcmp(t1->groups, t2->groups,
42 t1->ngroups*sizeof(gid_t)) != 0) {
43 return false;
45 return true;
48 /****************************************************************************
49 Become the specified uid.
50 ****************************************************************************/
52 static bool become_uid(uid_t uid)
54 /* Check for dodgy uid values */
56 if (uid == (uid_t)-1 ||
57 ((sizeof(uid_t) == 2) && (uid == (uid_t)65535))) {
58 if (!become_uid_done) {
59 DEBUG(1,("WARNING: using uid %d is a security risk\n",
60 (int)uid));
61 become_uid_done = true;
65 /* Set effective user id */
67 set_effective_uid(uid);
69 DO_PROFILE_INC(uid_changes);
70 return True;
73 /****************************************************************************
74 Become the specified gid.
75 ****************************************************************************/
77 static bool become_gid(gid_t gid)
79 /* Check for dodgy gid values */
81 if (gid == (gid_t)-1 || ((sizeof(gid_t) == 2) &&
82 (gid == (gid_t)65535))) {
83 if (!become_gid_done) {
84 DEBUG(1,("WARNING: using gid %d is a security risk\n",
85 (int)gid));
86 become_gid_done = true;
90 /* Set effective group id */
92 set_effective_gid(gid);
93 return True;
96 /****************************************************************************
97 Become the specified uid and gid.
98 ****************************************************************************/
100 static bool become_id(uid_t uid, gid_t gid)
102 return become_gid(gid) && become_uid(uid);
105 /****************************************************************************
106 Drop back to root privileges in order to change to another user.
107 ****************************************************************************/
109 static void gain_root(void)
111 if (non_root_mode()) {
112 return;
115 if (geteuid() != 0) {
116 set_effective_uid(0);
118 if (geteuid() != 0) {
119 DEBUG(0,
120 ("Warning: You appear to have a trapdoor "
121 "uid system\n"));
125 if (getegid() != 0) {
126 set_effective_gid(0);
128 if (getegid() != 0) {
129 DEBUG(0,
130 ("Warning: You appear to have a trapdoor "
131 "gid system\n"));
136 /****************************************************************************
137 Get the list of current groups.
138 ****************************************************************************/
140 static int get_current_groups(gid_t gid, uint32_t *p_ngroups, gid_t **p_groups)
142 int i;
143 gid_t grp;
144 int ngroups;
145 gid_t *groups = NULL;
147 (*p_ngroups) = 0;
148 (*p_groups) = NULL;
150 /* this looks a little strange, but is needed to cope with
151 systems that put the current egid in the group list
152 returned from getgroups() (tridge) */
153 save_re_gid();
154 set_effective_gid(gid);
155 samba_setgid(gid);
157 ngroups = sys_getgroups(0,&grp);
158 if (ngroups <= 0) {
159 goto fail;
162 if((groups = SMB_MALLOC_ARRAY(gid_t, ngroups+1)) == NULL) {
163 DEBUG(0,("setup_groups malloc fail !\n"));
164 goto fail;
167 if ((ngroups = sys_getgroups(ngroups,groups)) == -1) {
168 goto fail;
171 restore_re_gid();
173 (*p_ngroups) = ngroups;
174 (*p_groups) = groups;
176 DEBUG( 4, ( "get_current_groups: user is in %u groups: ", ngroups));
177 for (i = 0; i < ngroups; i++ ) {
178 DEBUG( 4, ( "%s%d", (i ? ", " : ""), (int)groups[i] ) );
180 DEBUG( 4, ( "\n" ) );
182 return ngroups;
184 fail:
185 SAFE_FREE(groups);
186 restore_re_gid();
187 return -1;
190 /****************************************************************************
191 Create a new security context on the stack. It is the same as the old
192 one. User changes are done using the set_sec_ctx() function.
193 ****************************************************************************/
195 bool push_sec_ctx(void)
197 struct sec_ctx *ctx_p;
199 /* Check we don't overflow our stack */
201 if (sec_ctx_stack_ndx == MAX_SEC_CTX_DEPTH) {
202 DEBUG(0, ("Security context stack overflow!\n"));
203 smb_panic("Security context stack overflow!");
206 /* Store previous user context */
208 sec_ctx_stack_ndx++;
210 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
212 ctx_p->ut.uid = geteuid();
213 ctx_p->ut.gid = getegid();
215 DEBUG(4, ("push_sec_ctx(%u, %u) : sec_ctx_stack_ndx = %d\n",
216 (unsigned int)ctx_p->ut.uid, (unsigned int)ctx_p->ut.gid, sec_ctx_stack_ndx ));
218 ctx_p->token = dup_nt_token(NULL,
219 sec_ctx_stack[sec_ctx_stack_ndx-1].token);
221 ctx_p->ut.ngroups = sys_getgroups(0, NULL);
223 if (ctx_p->ut.ngroups != 0) {
224 if (!(ctx_p->ut.groups = SMB_MALLOC_ARRAY(gid_t, ctx_p->ut.ngroups))) {
225 DEBUG(0, ("Out of memory in push_sec_ctx()\n"));
226 TALLOC_FREE(ctx_p->token);
227 return False;
230 sys_getgroups(ctx_p->ut.ngroups, ctx_p->ut.groups);
231 } else {
232 ctx_p->ut.groups = NULL;
235 return True;
238 /****************************************************************************
239 Change UNIX security context. Calls panic if not successful so no return value.
240 ****************************************************************************/
242 #ifndef HAVE_DARWIN_INITGROUPS
244 /* Normal credential switch path. */
246 static void set_unix_security_ctx(uid_t uid, gid_t gid, int ngroups, gid_t *groups)
248 /* Start context switch */
249 gain_root();
250 #ifdef HAVE_SETGROUPS
251 if (sys_setgroups(gid, ngroups, groups) != 0 && !non_root_mode()) {
252 smb_panic("sys_setgroups failed");
254 #endif
255 become_id(uid, gid);
256 /* end context switch */
259 #else /* HAVE_DARWIN_INITGROUPS */
261 /* The Darwin groups implementation is a little unusual. The list of
262 * groups in the kernel credential is not exhaustive, but more like
263 * a cache. The full group list is held in userspace and checked
264 * dynamically.
266 * This is an optional mechanism, and setgroups(2) opts out
267 * of it. That is, if you call setgroups, then the list of groups you
268 * set are the only groups that are ever checked. This is not what we
269 * want. We want to opt in to the dynamic resolution mechanism, so we
270 * need to specify the uid of the user whose group list (cache) we are
271 * setting.
273 * The Darwin rules are:
274 * 1. Thou shalt setegid, initgroups and seteuid IN THAT ORDER
275 * 2. Thou shalt not pass more that NGROUPS_MAX to initgroups
276 * 3. Thou shalt leave the first entry in the groups list well alone
279 #include <sys/syscall.h>
281 static void set_unix_security_ctx(uid_t uid, gid_t gid, int ngroups, gid_t *groups)
283 int max = groups_max();
285 /* Start context switch */
286 gain_root();
288 become_gid(gid);
291 if (syscall(SYS_initgroups, (ngroups > max) ? max : ngroups,
292 groups, uid) == -1 && !non_root_mode()) {
293 DEBUG(0, ("WARNING: failed to set group list "
294 "(%d groups) for UID %d: %s\n",
295 ngroups, uid, strerror(errno)));
296 smb_panic("sys_setgroups failed");
299 become_uid(uid);
300 /* end context switch */
303 #endif /* HAVE_DARWIN_INITGROUPS */
305 /****************************************************************************
306 Set the current security context to a given user.
307 ****************************************************************************/
309 void set_sec_ctx(uid_t uid, gid_t gid, int ngroups, gid_t *groups, const struct security_token *token)
311 struct sec_ctx *ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
313 /* Set the security context */
315 DEBUG(4, ("setting sec ctx (%u, %u) - sec_ctx_stack_ndx = %d\n",
316 (unsigned int)uid, (unsigned int)gid, sec_ctx_stack_ndx));
318 security_token_debug(DBGC_CLASS, 5, token);
319 debug_unix_user_token(DBGC_CLASS, 5, uid, gid, ngroups, groups);
321 /* Change uid, gid and supplementary group list. */
322 set_unix_security_ctx(uid, gid, ngroups, groups);
324 ctx_p->ut.ngroups = ngroups;
326 SAFE_FREE(ctx_p->ut.groups);
327 if (token && (token == ctx_p->token)) {
328 smb_panic("DUPLICATE_TOKEN");
331 TALLOC_FREE(ctx_p->token);
333 if (ngroups) {
334 ctx_p->ut.groups = (gid_t *)memdup(groups,
335 sizeof(gid_t) * ngroups);
336 if (!ctx_p->ut.groups) {
337 smb_panic("memdup failed");
339 } else {
340 ctx_p->ut.groups = NULL;
343 if (token) {
344 ctx_p->token = dup_nt_token(NULL, token);
345 if (!ctx_p->token) {
346 smb_panic("dup_nt_token failed");
348 } else {
349 ctx_p->token = NULL;
352 ctx_p->ut.uid = uid;
353 ctx_p->ut.gid = gid;
355 /* Update current_user stuff */
357 current_user.ut.uid = uid;
358 current_user.ut.gid = gid;
359 current_user.ut.ngroups = ngroups;
360 current_user.ut.groups = groups;
361 current_user.nt_user_token = ctx_p->token;
364 /****************************************************************************
365 Become root context.
366 ****************************************************************************/
368 void set_root_sec_ctx(void)
370 /* May need to worry about supplementary groups at some stage */
372 set_sec_ctx(0, 0, 0, NULL, NULL);
375 /****************************************************************************
376 Pop a security context from the stack.
377 ****************************************************************************/
379 bool pop_sec_ctx(void)
381 struct sec_ctx *ctx_p;
382 struct sec_ctx *prev_ctx_p;
384 /* Check for stack underflow */
386 if (sec_ctx_stack_ndx == 0) {
387 DEBUG(0, ("Security context stack underflow!\n"));
388 smb_panic("Security context stack underflow!");
391 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
393 /* Clear previous user info */
395 ctx_p->ut.uid = (uid_t)-1;
396 ctx_p->ut.gid = (gid_t)-1;
398 SAFE_FREE(ctx_p->ut.groups);
399 ctx_p->ut.ngroups = 0;
401 TALLOC_FREE(ctx_p->token);
403 /* Pop back previous user */
405 sec_ctx_stack_ndx--;
407 prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
409 /* Change uid, gid and supplementary group list. */
410 set_unix_security_ctx(prev_ctx_p->ut.uid,
411 prev_ctx_p->ut.gid,
412 prev_ctx_p->ut.ngroups,
413 prev_ctx_p->ut.groups);
415 /* Update current_user stuff */
417 current_user.ut.uid = prev_ctx_p->ut.uid;
418 current_user.ut.gid = prev_ctx_p->ut.gid;
419 current_user.ut.ngroups = prev_ctx_p->ut.ngroups;
420 current_user.ut.groups = prev_ctx_p->ut.groups;
421 current_user.nt_user_token = prev_ctx_p->token;
423 DEBUG(4, ("pop_sec_ctx (%u, %u) - sec_ctx_stack_ndx = %d\n",
424 (unsigned int)geteuid(), (unsigned int)getegid(), sec_ctx_stack_ndx));
426 return True;
429 /* Initialise the security context system */
431 void init_sec_ctx(void)
433 int i;
434 struct sec_ctx *ctx_p;
436 /* Initialise security context stack */
438 memset(sec_ctx_stack, 0, sizeof(struct sec_ctx) * MAX_SEC_CTX_DEPTH);
440 for (i = 0; i < MAX_SEC_CTX_DEPTH; i++) {
441 sec_ctx_stack[i].ut.uid = (uid_t)-1;
442 sec_ctx_stack[i].ut.gid = (gid_t)-1;
445 /* Initialise first level of stack. It is the current context */
446 ctx_p = &sec_ctx_stack[0];
448 ctx_p->ut.uid = geteuid();
449 ctx_p->ut.gid = getegid();
451 get_current_groups(ctx_p->ut.gid, &ctx_p->ut.ngroups, &ctx_p->ut.groups);
453 ctx_p->token = NULL; /* Maps to guest user. */
455 /* Initialise current_user global */
457 current_user.ut.uid = ctx_p->ut.uid;
458 current_user.ut.gid = ctx_p->ut.gid;
459 current_user.ut.ngroups = ctx_p->ut.ngroups;
460 current_user.ut.groups = ctx_p->ut.groups;
462 /* The conn and vuid are usually taken care of by other modules.
463 We initialise them here. */
465 current_user.conn = NULL;
466 current_user.vuid = UID_FIELD_INVALID;
467 current_user.nt_user_token = NULL;
470 /*************************************************************
471 Called when we're inside a become_root() temporary escalation
472 of privileges and the nt_user_token is NULL. Return the last
473 active token on the context stack. We know there is at least
474 one valid non-NULL token on the stack so panic if we underflow.
475 *************************************************************/
477 const struct security_token *sec_ctx_active_token(void)
479 int stack_index = sec_ctx_stack_ndx;
480 struct sec_ctx *ctx_p = &sec_ctx_stack[stack_index];
482 while (ctx_p->token == NULL) {
483 stack_index--;
484 if (stack_index < 0) {
485 DEBUG(0, ("Security context active token "
486 "stack underflow!\n"));
487 smb_panic("Security context active token "
488 "stack underflow!");
490 ctx_p = &sec_ctx_stack[stack_index];
492 return ctx_p->token;