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);
63 DO_PROFILE_INC(uid_changes);
67 /****************************************************************************
68 Become the specified gid.
69 ****************************************************************************/
71 static BOOL become_gid(gid_t gid)
73 /* Check for dodgy gid values */
75 if (gid == (gid_t)-1 || ((sizeof(gid_t) == 2) &&
76 (gid == (gid_t)65535))) {
80 DEBUG(1,("WARNING: using gid %d is a security risk\n",
86 /* Set effective group id */
88 set_effective_gid(gid);
92 /****************************************************************************
93 Become the specified uid and gid.
94 ****************************************************************************/
96 static BOOL become_id(uid_t uid, gid_t gid)
98 return become_gid(gid) && become_uid(uid);
101 /****************************************************************************
102 Drop back to root privileges in order to change to another user.
103 ****************************************************************************/
105 static void gain_root(void)
107 if (non_root_mode()) {
111 if (geteuid() != 0) {
112 set_effective_uid(0);
114 if (geteuid() != 0) {
116 ("Warning: You appear to have a trapdoor "
121 if (getegid() != 0) {
122 set_effective_gid(0);
124 if (getegid() != 0) {
126 ("Warning: You appear to have a trapdoor "
132 /****************************************************************************
133 Get the list of current groups.
134 ****************************************************************************/
136 int get_current_groups(int *p_ngroups, gid_t **p_groups)
140 int ngroups = sys_getgroups(0,&grp);
149 if((groups = (gid_t *)malloc(sizeof(gid_t)*ngroups)) == NULL) {
150 DEBUG(0,("setup_groups malloc fail !\n"));
154 if ((ngroups = sys_getgroups(ngroups,groups)) == -1) {
159 (*p_ngroups) = ngroups;
160 (*p_groups) = groups;
162 DEBUG( 3, ( "get_current_groups: user is in %u groups: ", ngroups));
163 for (i = 0; i < ngroups; i++ ) {
164 DEBUG( 3, ( "%s%d", (i ? ", " : ""), (int)groups[i] ) );
166 DEBUG( 3, ( "\n" ) );
171 /****************************************************************************
173 ****************************************************************************/
175 void delete_nt_token(NT_USER_TOKEN **pptoken)
178 NT_USER_TOKEN *ptoken = *pptoken;
179 SAFE_FREE( ptoken->user_sids );
180 ZERO_STRUCTP(ptoken);
185 /****************************************************************************
186 Duplicate a SID token.
187 ****************************************************************************/
189 NT_USER_TOKEN *dup_nt_token(NT_USER_TOKEN *ptoken)
191 NT_USER_TOKEN *token;
196 if ((token = (NT_USER_TOKEN *)malloc( sizeof(NT_USER_TOKEN) ) ) == NULL)
201 if ((token->user_sids = (DOM_SID *)memdup( ptoken->user_sids, sizeof(DOM_SID) * ptoken->num_sids )) == NULL) {
206 token->num_sids = ptoken->num_sids;
211 /****************************************************************************
212 Initialize the groups a user belongs to.
213 ****************************************************************************/
215 BOOL initialise_groups(char *user, uid_t uid, gid_t gid)
217 struct sec_ctx *prev_ctx_p;
220 if (non_root_mode()) {
226 /* Call initgroups() to get user groups */
228 if (winbind_initgroups(user,gid) == -1) {
229 DEBUG(0,("Unable to initgroups. Error was %s\n", strerror(errno) ));
231 if (gid < 0 || gid > 32767 || uid < 0 || uid > 32767) {
232 DEBUG(0,("This is probably a problem with the account %s\n", user));
239 /* Store groups in previous user's security context. This will
240 always work as the become_root() call increments the stack
243 prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx - 1];
245 SAFE_FREE(prev_ctx_p->groups);
246 prev_ctx_p->ngroups = 0;
248 get_current_groups(&prev_ctx_p->ngroups, &prev_ctx_p->groups);
256 /****************************************************************************
257 Create a new security context on the stack. It is the same as the old
258 one. User changes are done using the set_sec_ctx() function.
259 ****************************************************************************/
261 BOOL push_sec_ctx(void)
263 struct sec_ctx *ctx_p;
265 /* Check we don't overflow our stack */
267 if (sec_ctx_stack_ndx == MAX_SEC_CTX_DEPTH) {
268 DEBUG(0, ("Security context stack overflow!\n"));
269 smb_panic("Security context stack overflow!\n");
272 /* Store previous user context */
276 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
278 ctx_p->uid = geteuid();
279 ctx_p->gid = getegid();
281 DEBUG(3, ("push_sec_ctx(%u, %u) : sec_ctx_stack_ndx = %d\n",
282 (unsigned int)ctx_p->uid, (unsigned int)ctx_p->gid, sec_ctx_stack_ndx ));
284 ctx_p->token = dup_nt_token(sec_ctx_stack[sec_ctx_stack_ndx-1].token);
286 ctx_p->ngroups = sys_getgroups(0, NULL);
288 if (ctx_p->ngroups != 0) {
289 if (!(ctx_p->groups = malloc(ctx_p->ngroups * sizeof(gid_t)))) {
290 DEBUG(0, ("Out of memory in push_sec_ctx()\n"));
291 delete_nt_token(&ctx_p->token);
295 sys_getgroups(ctx_p->ngroups, ctx_p->groups);
297 ctx_p->groups = NULL;
303 /****************************************************************************
304 Set the current security context to a given user.
305 ****************************************************************************/
307 void set_sec_ctx(uid_t uid, gid_t gid, int ngroups, gid_t *groups, NT_USER_TOKEN *token)
309 struct sec_ctx *ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
311 /* Set the security context */
313 DEBUG(3, ("setting sec ctx (%u, %u) - sec_ctx_stack_ndx = %d\n",
314 (unsigned int)uid, (unsigned int)gid, sec_ctx_stack_ndx));
319 DEBUG(3, ("%d user groups: \n", ngroups));
320 for (i = 0; i < ngroups; i++) {
321 DEBUGADD(3, ("%u ", (unsigned int)groups[i]));
330 #ifdef HAVE_SETGROUPS
331 sys_setgroups(ngroups, groups);
334 ctx_p->ngroups = ngroups;
336 SAFE_FREE(ctx_p->groups);
337 if (token && (token == ctx_p->token))
338 smb_panic("DUPLICATE_TOKEN");
340 delete_nt_token(&ctx_p->token);
342 ctx_p->groups = memdup(groups, sizeof(gid_t) * ngroups);
343 ctx_p->token = dup_nt_token(token);
350 /* Update current_user stuff */
352 current_user.uid = uid;
353 current_user.gid = gid;
354 current_user.ngroups = ngroups;
355 current_user.groups = groups;
356 current_user.nt_user_token = ctx_p->token;
359 /****************************************************************************
361 ****************************************************************************/
363 void set_root_sec_ctx(void)
365 /* May need to worry about supplementary groups at some stage */
367 set_sec_ctx(0, 0, 0, NULL, NULL);
370 /****************************************************************************
371 Pop a security context from the stack.
372 ****************************************************************************/
374 BOOL pop_sec_ctx(void)
376 struct sec_ctx *ctx_p;
377 struct sec_ctx *prev_ctx_p;
379 /* Check for stack underflow */
381 if (sec_ctx_stack_ndx == 0) {
382 DEBUG(0, ("Security context stack underflow!\n"));
383 smb_panic("Security context stack underflow!\n");
386 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
388 /* Clear previous user info */
390 ctx_p->uid = (uid_t)-1;
391 ctx_p->gid = (gid_t)-1;
393 SAFE_FREE(ctx_p->groups);
396 delete_nt_token(&ctx_p->token);
398 /* Pop back previous user */
404 prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
406 #ifdef HAVE_SETGROUPS
407 sys_setgroups(prev_ctx_p->ngroups, prev_ctx_p->groups);
410 become_id(prev_ctx_p->uid, prev_ctx_p->gid);
412 /* Update current_user stuff */
414 current_user.uid = prev_ctx_p->uid;
415 current_user.gid = prev_ctx_p->gid;
416 current_user.ngroups = prev_ctx_p->ngroups;
417 current_user.groups = prev_ctx_p->groups;
418 current_user.nt_user_token = prev_ctx_p->token;
420 DEBUG(3, ("pop_sec_ctx (%u, %u) - sec_ctx_stack_ndx = %d\n",
421 (unsigned int)geteuid(), (unsigned int)getegid(), sec_ctx_stack_ndx));
426 /* Initialise the security context system */
428 void init_sec_ctx(void)
431 struct sec_ctx *ctx_p;
433 /* Initialise security context stack */
435 memset(sec_ctx_stack, 0, sizeof(struct sec_ctx) * MAX_SEC_CTX_DEPTH);
437 for (i = 0; i < MAX_SEC_CTX_DEPTH; i++) {
438 sec_ctx_stack[i].uid = (uid_t)-1;
439 sec_ctx_stack[i].gid = (gid_t)-1;
442 /* Initialise first level of stack. It is the current context */
443 ctx_p = &sec_ctx_stack[0];
445 ctx_p->uid = geteuid();
446 ctx_p->gid = getegid();
448 get_current_groups(&ctx_p->ngroups, &ctx_p->groups);
450 ctx_p->token = NULL; /* Maps to guest user. */
452 /* Initialise current_user global */
454 current_user.uid = ctx_p->uid;
455 current_user.gid = ctx_p->gid;
456 current_user.ngroups = ctx_p->ngroups;
457 current_user.groups = ctx_p->groups;
459 /* The conn and vuid are usually taken care of by other modules.
460 We initialise them here. */
462 current_user.conn = NULL;
463 current_user.vuid = UID_FIELD_INVALID;
464 current_user.nt_user_token = NULL;