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 int DEBUGLEVEL;
25 extern struct current_user current_user;
35 /* A stack of security contexts. We include the current context as being
36 the first one, so there is room for another MAX_SEC_CTX_DEPTH more. */
38 static struct sec_ctx sec_ctx_stack[MAX_SEC_CTX_DEPTH + 1];
39 static int sec_ctx_stack_ndx;
41 /****************************************************************************
42 Become the specified uid.
43 ****************************************************************************/
45 static BOOL become_uid(uid_t uid)
47 /* Check for dodgy uid values */
49 if (uid == (uid_t)-1 ||
50 ((sizeof(uid_t) == 2) && (uid == (uid_t)65535))) {
54 DEBUG(1,("WARNING: using uid %d is a security risk\n",
60 /* Set effective user id */
62 set_effective_uid(uid);
63 current_user.uid = uid;
66 profile_p->uid_changes++;
72 /****************************************************************************
73 Become the specified gid.
74 ****************************************************************************/
76 static BOOL become_gid(gid_t gid)
78 /* Check for dodgy gid values */
80 if (gid == (gid_t)-1 || ((sizeof(gid_t) == 2) &&
81 (gid == (gid_t)65535))) {
85 DEBUG(1,("WARNING: using gid %d is a security risk\n",
91 /* Set effective group id */
93 set_effective_gid(gid);
94 current_user.gid = gid;
99 /****************************************************************************
100 Become the specified uid and gid.
101 ****************************************************************************/
103 static BOOL become_id(uid_t uid, gid_t gid)
105 return become_gid(gid) && become_uid(uid);
108 /****************************************************************************
109 Drop back to root privileges in order to change to another user.
110 ****************************************************************************/
112 static void gain_root(void)
114 if (geteuid() != 0) {
115 set_effective_uid(0);
117 if (geteuid() != 0) {
119 ("Warning: You appear to have a trapdoor "
124 if (getegid() != 0) {
125 set_effective_gid(0);
127 if (getegid() != 0) {
129 ("Warning: You appear to have a trapdoor "
135 /****************************************************************************
136 Get the list of current groups.
137 ****************************************************************************/
139 int get_current_groups(int *p_ngroups, gid_t **p_groups)
143 int ngroups = sys_getgroups(0,&grp);
152 if((groups = (gid_t *)malloc(sizeof(gid_t)*ngroups)) == NULL) {
153 DEBUG(0,("setup_groups malloc fail !\n"));
157 if ((ngroups = sys_getgroups(ngroups,groups)) == -1)
160 (*p_ngroups) = ngroups;
161 (*p_groups) = groups;
163 DEBUG( 3, ( "get_current_groups: uid %u is in %u groups: ", (unsigned int)getuid() , ngroups ) );
164 for (i = 0; i < ngroups; i++ ) {
165 DEBUG( 3, ( "%s%d", (i ? ", " : ""), (int)groups[i] ) );
167 DEBUG( 3, ( "\n" ) );
172 /****************************************************************************
174 ****************************************************************************/
176 void delete_nt_token(NT_USER_TOKEN **pptoken)
179 NT_USER_TOKEN *ptoken = *pptoken;
180 safe_free( ptoken->user_sids );
181 ZERO_STRUCTP(ptoken);
187 /****************************************************************************
188 Duplicate a SID token.
189 ****************************************************************************/
191 NT_USER_TOKEN *dup_nt_token(NT_USER_TOKEN *ptoken)
193 NT_USER_TOKEN *token;
198 if ((token = (NT_USER_TOKEN *)malloc( sizeof(NT_USER_TOKEN) ) ) == NULL)
203 if ((token->user_sids = (DOM_SID *)memdup( ptoken->user_sids, sizeof(DOM_SID) * ptoken->num_sids )) == NULL) {
208 token->num_sids = ptoken->num_sids;
213 /****************************************************************************
214 Create a new security context on the stack. It is the same as the old
215 one. User changes are done using the set_sec_ctx() function.
216 ****************************************************************************/
218 BOOL push_sec_ctx(void)
220 struct sec_ctx *ctx_p;
222 /* Check we don't overflow our stack */
224 if (sec_ctx_stack_ndx == (MAX_SEC_CTX_DEPTH)) {
225 DEBUG(0, ("Security context stack overflow!\n"));
229 /* Store previous user context */
233 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
235 ctx_p->uid = geteuid();
236 ctx_p->gid = getegid();
238 ctx_p->token = dup_nt_token(sec_ctx_stack[sec_ctx_stack_ndx-1].token);
240 ctx_p->ngroups = sys_getgroups(0, NULL);
242 if (ctx_p->ngroups != 0) {
243 if (!(ctx_p->groups = malloc(ctx_p->ngroups * sizeof(gid_t)))) {
244 DEBUG(0, ("Out of memory in push_sec_ctx()\n"));
245 delete_nt_token(&ctx_p->token);
249 sys_getgroups(ctx_p->ngroups, ctx_p->groups);
251 ctx_p->groups = NULL;
257 /****************************************************************************
258 Set the current security context to a given user.
259 ****************************************************************************/
261 void set_sec_ctx(uid_t uid, gid_t gid, int ngroups, gid_t *groups, NT_USER_TOKEN *token)
263 struct sec_ctx *ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
265 /* Set the security context */
267 DEBUG(3, ("setting sec ctx (%d, %d)\n", uid, gid));
271 #ifdef HAVE_SETGROUPS
272 sys_setgroups(ngroups, groups);
275 ctx_p->ngroups = ngroups;
277 safe_free(ctx_p->groups);
278 delete_nt_token(&ctx_p->token);
280 ctx_p->groups = memdup(groups, sizeof(gid_t) * ngroups);
281 ctx_p->token = dup_nt_token(token);
288 /* Update current_user stuff */
290 current_user.uid = uid;
291 current_user.gid = gid;
292 current_user.ngroups = ngroups;
293 current_user.groups = groups;
294 current_user.nt_user_token = token;
297 /****************************************************************************
299 ****************************************************************************/
301 void set_root_sec_ctx(void)
303 /* May need to worry about supplementary groups at some stage */
305 set_sec_ctx(0, 0, 0, NULL, NULL);
308 /****************************************************************************
309 Pop a security context from the stack.
310 ****************************************************************************/
312 BOOL pop_sec_ctx(void)
314 struct sec_ctx *ctx_p;
315 struct sec_ctx *prev_ctx_p;
317 /* Check for stack underflow */
319 if (sec_ctx_stack_ndx == 0) {
320 DEBUG(0, ("Security context stack underflow!\n"));
324 ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
326 /* Clear previous user info */
328 ctx_p->uid = (uid_t)-1;
329 ctx_p->gid = (gid_t)-1;
331 safe_free(ctx_p->groups);
334 delete_nt_token(&ctx_p->token);
336 /* Pop back previous user */
342 prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
344 #ifdef HAVE_SETGROUPS
345 sys_setgroups(prev_ctx_p->ngroups, prev_ctx_p->groups);
348 become_id(prev_ctx_p->uid, prev_ctx_p->gid);
350 /* Update current_user stuff */
352 current_user.uid = prev_ctx_p->uid;
353 current_user.gid = prev_ctx_p->gid;
354 current_user.ngroups = prev_ctx_p->ngroups;
355 current_user.groups = prev_ctx_p->groups;
356 current_user.nt_user_token = prev_ctx_p->token;
358 DEBUG(3, ("popped off to sec ctx (%d, %d)\n", geteuid(), getegid()));
363 /* Initialise the security context system */
365 void init_sec_ctx(void)
368 struct sec_ctx *ctx_p;
370 /* Initialise security context stack */
372 memset(sec_ctx_stack, 0, sizeof(struct sec_ctx) * MAX_SEC_CTX_DEPTH);
374 for (i = 0; i < MAX_SEC_CTX_DEPTH; i++) {
375 sec_ctx_stack[i].uid = (uid_t)-1;
376 sec_ctx_stack[i].gid = (gid_t)-1;
379 /* Initialise first level of stack. It is the current context */
380 ctx_p = &sec_ctx_stack[0];
382 ctx_p->uid = geteuid();
383 ctx_p->gid = getegid();
385 get_current_groups(&ctx_p->ngroups, &ctx_p->groups);
387 ctx_p->token = NULL; /* Maps to guest user. */
389 /* Initialise current_user global */
391 current_user.uid = ctx_p->uid;
392 current_user.gid = ctx_p->gid;
393 current_user.ngroups = ctx_p->ngroups;
394 current_user.groups = ctx_p->groups;
396 /* The conn and vuid are usually taken care of by other modules.
397 We initialise them here. */
399 current_user.conn = NULL;
400 current_user.vuid = UID_FIELD_INVALID;
401 current_user.nt_user_token = NULL;