3 Unix SMB/Netbios implementation.
6 Copyright (C) Tim Potter 2000
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 extern int DEBUGLEVEL;
26 extern struct current_user current_user;
36 /* A stack of security contexts. We include the current context as being
37 the first one, so there is room for another MAX_SEC_CTX_DEPTH more. */
39 static struct sec_ctx sec_ctx_stack[MAX_SEC_CTX_DEPTH + 1];
40 static int sec_ctx_stack_ndx;
42 /****************************************************************************
43 Become the specified uid.
44 ****************************************************************************/
46 static BOOL become_uid(uid_t uid)
48 /* Check for dodgy uid values */
50 if (uid == (uid_t)-1 ||
51 ((sizeof(uid_t) == 2) && (uid == (uid_t)65535))) {
55 DEBUG(1,("WARNING: using uid %d is a security risk\n",
61 /* Set effective user id */
63 set_effective_uid(uid);
64 current_user.uid = uid;
66 DO_PROFILE_INC(uid_changes);
71 /****************************************************************************
72 Become the specified gid.
73 ****************************************************************************/
75 static BOOL become_gid(gid_t gid)
77 /* Check for dodgy gid values */
79 if (gid == (gid_t)-1 || ((sizeof(gid_t) == 2) &&
80 (gid == (gid_t)65535))) {
84 DEBUG(1,("WARNING: using gid %d is a security risk\n",
90 /* Set effective group id */
92 set_effective_gid(gid);
93 current_user.gid = gid;
98 /****************************************************************************
99 Become the specified uid and gid.
100 ****************************************************************************/
102 static BOOL become_id(uid_t uid, gid_t gid)
104 return become_gid(gid) && become_uid(uid);
107 /****************************************************************************
108 Drop back to root privileges in order to change to another user.
109 ****************************************************************************/
111 static void gain_root(void)
113 if (geteuid() != 0) {
114 set_effective_uid(0);
116 if (geteuid() != 0) {
118 ("Warning: You appear to have a trapdoor "
123 if (getegid() != 0) {
124 set_effective_gid(0);
126 if (getegid() != 0) {
128 ("Warning: You appear to have a trapdoor "
134 /****************************************************************************
135 Get the list of current groups.
136 ****************************************************************************/
138 int get_current_groups(int *p_ngroups, gid_t **p_groups)
142 int ngroups = sys_getgroups(0,&grp);
151 if((groups = (gid_t *)malloc(sizeof(gid_t)*ngroups)) == NULL) {
152 DEBUG(0,("setup_groups malloc fail !\n"));
156 if ((ngroups = sys_getgroups(ngroups,groups)) == -1)
159 (*p_ngroups) = ngroups;
160 (*p_groups) = groups;
162 DEBUG( 3, ( "get_current_groups: uid %u is in %u groups: ", (unsigned int)getuid() , 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);
186 /****************************************************************************
187 Duplicate a SID token.
188 ****************************************************************************/
190 NT_USER_TOKEN *dup_nt_token(NT_USER_TOKEN *ptoken)
192 NT_USER_TOKEN *token;
197 if ((token = (NT_USER_TOKEN *)malloc( sizeof(NT_USER_TOKEN) ) ) == NULL)
202 if ((token->user_sids = (DOM_SID *)memdup( ptoken->user_sids, sizeof(DOM_SID) * ptoken->num_sids )) == NULL) {
207 token->num_sids = ptoken->num_sids;
212 /****************************************************************************
213 Initialize the groups a user belongs to.
214 ****************************************************************************/
216 BOOL initialise_groups(char *user, uid_t uid, gid_t gid)
218 struct sec_ctx *prev_ctx_p;
223 /* Call initgroups() to get user groups */
225 if (winbind_initgroups(user,gid) == -1) {
226 DEBUG(0,("Unable to initgroups. Error was %s\n", strerror(errno) ));
228 if (gid < 0 || gid > 32767 || uid < 0 || uid > 32767) {
229 DEBUG(0,("This is probably a problem with the account %s\n", user));
236 /* Store groups in previous user's security context. This will
237 always work as the become_root() call increments the stack
240 prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx - 1];
242 safe_free(prev_ctx_p->groups);
243 prev_ctx_p->groups = NULL;
244 prev_ctx_p->ngroups = 0;
246 get_current_groups(&prev_ctx_p->ngroups, &prev_ctx_p->groups);
254 /****************************************************************************
255 Create a new security context on the stack. It is the same as the old
256 one. User changes are done using the set_sec_ctx() function.
257 ****************************************************************************/
259 BOOL push_sec_ctx(void)
261 struct sec_ctx *ctx_p;
263 /* Check we don't overflow our stack */
265 if (sec_ctx_stack_ndx == MAX_SEC_CTX_DEPTH) {
266 DEBUG(0, ("Security context stack overflow!\n"));
267 smb_panic("Security context stack overflow!\n");
270 /* Store previous user context */
274 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
276 ctx_p->uid = geteuid();
277 ctx_p->gid = getegid();
279 DEBUG(3, ("push_sec_ctx(%d, %d) : sec_ctx_stack_ndx = %d\n",
280 ctx_p->uid, ctx_p->gid, sec_ctx_stack_ndx ));
282 ctx_p->token = dup_nt_token(sec_ctx_stack[sec_ctx_stack_ndx-1].token);
284 ctx_p->ngroups = sys_getgroups(0, NULL);
286 if (ctx_p->ngroups != 0) {
287 if (!(ctx_p->groups = malloc(ctx_p->ngroups * sizeof(gid_t)))) {
288 DEBUG(0, ("Out of memory in push_sec_ctx()\n"));
289 delete_nt_token(&ctx_p->token);
293 sys_getgroups(ctx_p->ngroups, ctx_p->groups);
295 ctx_p->groups = NULL;
301 /****************************************************************************
302 Set the current security context to a given user.
303 ****************************************************************************/
305 void set_sec_ctx(uid_t uid, gid_t gid, int ngroups, gid_t *groups, NT_USER_TOKEN *token)
307 struct sec_ctx *ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
309 /* Set the security context */
311 DEBUG(3, ("setting sec ctx (%d, %d) - sec_ctx_stack_ndx = %d\n", uid, gid, sec_ctx_stack_ndx));
316 DEBUG(3, ("%d user groups: \n", ngroups));
317 for (i = 0; i < ngroups; i++) {
318 DEBUGADD(3, ("%d ", groups[i]));
327 #ifdef HAVE_SETGROUPS
328 sys_setgroups(ngroups, groups);
331 ctx_p->ngroups = ngroups;
333 safe_free(ctx_p->groups);
334 if (token && (token == ctx_p->token))
335 smb_panic("DUPLICATE_TOKEN");
337 delete_nt_token(&ctx_p->token);
339 ctx_p->groups = memdup(groups, sizeof(gid_t) * ngroups);
340 ctx_p->token = dup_nt_token(token);
347 /* Update current_user stuff */
349 current_user.uid = uid;
350 current_user.gid = gid;
351 current_user.ngroups = ngroups;
352 current_user.groups = groups;
353 current_user.nt_user_token = token;
356 /****************************************************************************
358 ****************************************************************************/
360 void set_root_sec_ctx(void)
362 /* May need to worry about supplementary groups at some stage */
364 set_sec_ctx(0, 0, 0, NULL, NULL);
367 /****************************************************************************
368 Pop a security context from the stack.
369 ****************************************************************************/
371 BOOL pop_sec_ctx(void)
373 struct sec_ctx *ctx_p;
374 struct sec_ctx *prev_ctx_p;
376 /* Check for stack underflow */
378 if (sec_ctx_stack_ndx == 0) {
379 DEBUG(0, ("Security context stack underflow!\n"));
380 smb_panic("Security context stack underflow!\n");
383 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
385 /* Clear previous user info */
387 ctx_p->uid = (uid_t)-1;
388 ctx_p->gid = (gid_t)-1;
390 safe_free(ctx_p->groups);
393 delete_nt_token(&ctx_p->token);
395 /* Pop back previous user */
401 prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
403 #ifdef HAVE_SETGROUPS
404 sys_setgroups(prev_ctx_p->ngroups, prev_ctx_p->groups);
407 become_id(prev_ctx_p->uid, prev_ctx_p->gid);
409 /* Update current_user stuff */
411 current_user.uid = prev_ctx_p->uid;
412 current_user.gid = prev_ctx_p->gid;
413 current_user.ngroups = prev_ctx_p->ngroups;
414 current_user.groups = prev_ctx_p->groups;
415 current_user.nt_user_token = prev_ctx_p->token;
417 DEBUG(3, ("pop_sec_ctx (%d, %d) - sec_ctx_stack_ndx = %d\n", geteuid(), getegid(), sec_ctx_stack_ndx));
422 /* Initialise the security context system */
424 void init_sec_ctx(void)
427 struct sec_ctx *ctx_p;
429 /* Initialise security context stack */
431 memset(sec_ctx_stack, 0, sizeof(struct sec_ctx) * MAX_SEC_CTX_DEPTH);
433 for (i = 0; i < MAX_SEC_CTX_DEPTH; i++) {
434 sec_ctx_stack[i].uid = (uid_t)-1;
435 sec_ctx_stack[i].gid = (gid_t)-1;
438 /* Initialise first level of stack. It is the current context */
439 ctx_p = &sec_ctx_stack[0];
441 ctx_p->uid = geteuid();
442 ctx_p->gid = getegid();
444 get_current_groups(&ctx_p->ngroups, &ctx_p->groups);
446 ctx_p->token = NULL; /* Maps to guest user. */
448 /* Initialise current_user global */
450 current_user.uid = ctx_p->uid;
451 current_user.gid = ctx_p->gid;
452 current_user.ngroups = ctx_p->ngroups;
453 current_user.groups = ctx_p->groups;
455 /* The conn and vuid are usually taken care of by other modules.
456 We initialise them here. */
458 current_user.conn = NULL;
459 current_user.vuid = UID_FIELD_INVALID;
460 current_user.nt_user_token = NULL;