2 Unix SMB/Netbios implementation.
5 Copyright (C) Tim Potter 2000
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 extern struct current_user current_user;
34 /* A stack of security contexts. We include the current context as being
35 the first one, so there is room for another MAX_SEC_CTX_DEPTH more. */
37 static struct sec_ctx sec_ctx_stack[MAX_SEC_CTX_DEPTH + 1];
38 static int sec_ctx_stack_ndx;
40 /****************************************************************************
41 Become the specified uid.
42 ****************************************************************************/
44 static BOOL become_uid(uid_t uid)
46 /* Check for dodgy uid values */
48 if (uid == (uid_t)-1 ||
49 ((sizeof(uid_t) == 2) && (uid == (uid_t)65535))) {
53 DEBUG(1,("WARNING: using uid %d is a security risk\n",
59 /* Set effective user id */
61 set_effective_uid(uid);
62 current_user.uid = uid;
64 DO_PROFILE_INC(uid_changes);
69 /****************************************************************************
70 Become the specified gid.
71 ****************************************************************************/
73 static BOOL become_gid(gid_t gid)
75 /* Check for dodgy gid values */
77 if (gid == (gid_t)-1 || ((sizeof(gid_t) == 2) &&
78 (gid == (gid_t)65535))) {
82 DEBUG(1,("WARNING: using gid %d is a security risk\n",
88 /* Set effective group id */
90 set_effective_gid(gid);
91 current_user.gid = gid;
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()) {
115 if (geteuid() != 0) {
116 set_effective_uid(0);
118 if (geteuid() != 0) {
120 ("Warning: You appear to have a trapdoor "
125 if (getegid() != 0) {
126 set_effective_gid(0);
128 if (getegid() != 0) {
130 ("Warning: You appear to have a trapdoor "
136 /****************************************************************************
137 Get the list of current groups.
138 ****************************************************************************/
140 int get_current_groups(int *p_ngroups, gid_t **p_groups)
144 int ngroups = sys_getgroups(0,&grp);
153 if((groups = (gid_t *)malloc(sizeof(gid_t)*ngroups)) == NULL) {
154 DEBUG(0,("setup_groups malloc fail !\n"));
158 if ((ngroups = sys_getgroups(ngroups,groups)) == -1) {
163 (*p_ngroups) = ngroups;
164 (*p_groups) = groups;
166 DEBUG( 3, ( "get_current_groups: uid %u is in %u groups: ", (unsigned int)getuid() , ngroups ) );
167 for (i = 0; i < ngroups; i++ ) {
168 DEBUG( 3, ( "%s%d", (i ? ", " : ""), (int)groups[i] ) );
170 DEBUG( 3, ( "\n" ) );
175 /****************************************************************************
177 ****************************************************************************/
179 void delete_nt_token(NT_USER_TOKEN **pptoken)
182 NT_USER_TOKEN *ptoken = *pptoken;
183 SAFE_FREE( ptoken->user_sids );
184 ZERO_STRUCTP(ptoken);
189 /****************************************************************************
190 Duplicate a SID token.
191 ****************************************************************************/
193 NT_USER_TOKEN *dup_nt_token(NT_USER_TOKEN *ptoken)
195 NT_USER_TOKEN *token;
200 if ((token = (NT_USER_TOKEN *)malloc( sizeof(NT_USER_TOKEN) ) ) == NULL)
205 if ((token->user_sids = (DOM_SID *)memdup( ptoken->user_sids, sizeof(DOM_SID) * ptoken->num_sids )) == NULL) {
210 token->num_sids = ptoken->num_sids;
215 /****************************************************************************
216 Initialize the groups a user belongs to.
217 ****************************************************************************/
219 BOOL initialise_groups(char *user, uid_t uid, gid_t gid)
221 struct sec_ctx *prev_ctx_p;
224 if (non_root_mode()) {
230 /* Call initgroups() to get user groups */
232 if (winbind_initgroups(user,gid) == -1) {
233 DEBUG(0,("Unable to initgroups. Error was %s\n", strerror(errno) ));
235 if (gid < 0 || gid > 32767 || uid < 0 || uid > 32767) {
236 DEBUG(0,("This is probably a problem with the account %s\n", user));
243 /* Store groups in previous user's security context. This will
244 always work as the become_root() call increments the stack
247 prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx - 1];
249 SAFE_FREE(prev_ctx_p->groups);
250 prev_ctx_p->ngroups = 0;
252 get_current_groups(&prev_ctx_p->ngroups, &prev_ctx_p->groups);
260 /****************************************************************************
261 Create a new security context on the stack. It is the same as the old
262 one. User changes are done using the set_sec_ctx() function.
263 ****************************************************************************/
265 BOOL push_sec_ctx(void)
267 struct sec_ctx *ctx_p;
269 /* Check we don't overflow our stack */
271 if (sec_ctx_stack_ndx == MAX_SEC_CTX_DEPTH) {
272 DEBUG(0, ("Security context stack overflow!\n"));
273 smb_panic("Security context stack overflow!\n");
276 /* Store previous user context */
280 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
282 ctx_p->uid = geteuid();
283 ctx_p->gid = getegid();
285 DEBUG(3, ("push_sec_ctx(%u, %u) : sec_ctx_stack_ndx = %d\n",
286 (unsigned int)ctx_p->uid, (unsigned int)ctx_p->gid, sec_ctx_stack_ndx ));
288 ctx_p->token = dup_nt_token(sec_ctx_stack[sec_ctx_stack_ndx-1].token);
290 ctx_p->ngroups = sys_getgroups(0, NULL);
292 if (ctx_p->ngroups != 0) {
293 if (!(ctx_p->groups = malloc(ctx_p->ngroups * sizeof(gid_t)))) {
294 DEBUG(0, ("Out of memory in push_sec_ctx()\n"));
295 delete_nt_token(&ctx_p->token);
299 sys_getgroups(ctx_p->ngroups, ctx_p->groups);
301 ctx_p->groups = NULL;
307 /****************************************************************************
308 Set the current security context to a given user.
309 ****************************************************************************/
311 void set_sec_ctx(uid_t uid, gid_t gid, int ngroups, gid_t *groups, NT_USER_TOKEN *token)
313 struct sec_ctx *ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
315 /* Set the security context */
317 DEBUG(3, ("setting sec ctx (%u, %u) - sec_ctx_stack_ndx = %d\n",
318 (unsigned int)uid, (unsigned int)gid, sec_ctx_stack_ndx));
323 DEBUG(3, ("%d user groups: \n", ngroups));
324 for (i = 0; i < ngroups; i++) {
325 DEBUGADD(3, ("%u ", (unsigned int)groups[i]));
334 #ifdef HAVE_SETGROUPS
335 sys_setgroups(ngroups, groups);
338 ctx_p->ngroups = ngroups;
340 SAFE_FREE(ctx_p->groups);
341 if (token && (token == ctx_p->token))
342 smb_panic("DUPLICATE_TOKEN");
344 delete_nt_token(&ctx_p->token);
346 ctx_p->groups = memdup(groups, sizeof(gid_t) * ngroups);
347 ctx_p->token = dup_nt_token(token);
354 /* Update current_user stuff */
356 current_user.uid = uid;
357 current_user.gid = gid;
358 current_user.ngroups = ngroups;
359 current_user.groups = groups;
360 current_user.nt_user_token = ctx_p->token;
363 /****************************************************************************
365 ****************************************************************************/
367 void set_root_sec_ctx(void)
369 /* May need to worry about supplementary groups at some stage */
371 set_sec_ctx(0, 0, 0, NULL, NULL);
374 /****************************************************************************
375 Pop a security context from the stack.
376 ****************************************************************************/
378 BOOL pop_sec_ctx(void)
380 struct sec_ctx *ctx_p;
381 struct sec_ctx *prev_ctx_p;
383 /* Check for stack underflow */
385 if (sec_ctx_stack_ndx == 0) {
386 DEBUG(0, ("Security context stack underflow!\n"));
387 smb_panic("Security context stack underflow!\n");
390 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
392 /* Clear previous user info */
394 ctx_p->uid = (uid_t)-1;
395 ctx_p->gid = (gid_t)-1;
397 SAFE_FREE(ctx_p->groups);
400 delete_nt_token(&ctx_p->token);
402 /* Pop back previous user */
408 prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
410 #ifdef HAVE_SETGROUPS
411 sys_setgroups(prev_ctx_p->ngroups, prev_ctx_p->groups);
414 become_id(prev_ctx_p->uid, prev_ctx_p->gid);
416 /* Update current_user stuff */
418 current_user.uid = prev_ctx_p->uid;
419 current_user.gid = prev_ctx_p->gid;
420 current_user.ngroups = prev_ctx_p->ngroups;
421 current_user.groups = prev_ctx_p->groups;
422 current_user.nt_user_token = prev_ctx_p->token;
424 DEBUG(3, ("pop_sec_ctx (%u, %u) - sec_ctx_stack_ndx = %d\n",
425 (unsigned int)geteuid(), (unsigned int)getegid(), sec_ctx_stack_ndx));
430 /* Initialise the security context system */
432 void init_sec_ctx(void)
435 struct sec_ctx *ctx_p;
437 /* Initialise security context stack */
439 memset(sec_ctx_stack, 0, sizeof(struct sec_ctx) * MAX_SEC_CTX_DEPTH);
441 for (i = 0; i < MAX_SEC_CTX_DEPTH; i++) {
442 sec_ctx_stack[i].uid = (uid_t)-1;
443 sec_ctx_stack[i].gid = (gid_t)-1;
446 /* Initialise first level of stack. It is the current context */
447 ctx_p = &sec_ctx_stack[0];
449 ctx_p->uid = geteuid();
450 ctx_p->gid = getegid();
452 get_current_groups(&ctx_p->ngroups, &ctx_p->groups);
454 ctx_p->token = NULL; /* Maps to guest user. */
456 /* Initialise current_user global */
458 current_user.uid = ctx_p->uid;
459 current_user.gid = ctx_p->gid;
460 current_user.ngroups = ctx_p->ngroups;
461 current_user.groups = ctx_p->groups;
463 /* The conn and vuid are usually taken care of by other modules.
464 We initialise them here. */
466 current_user.conn = NULL;
467 current_user.vuid = UID_FIELD_INVALID;
468 current_user.nt_user_token = NULL;