summaryrefslogtreecommitdiffstats
path: root/source/smbd/uid.c
blob: f76fa49d56cb5a99f5fa6248a6485113fec69b3e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   uid/user handling
   Copyright (C) Andrew Tridgell 1992-1998
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

extern int DEBUGLEVEL;

static uid_t initial_uid;
static gid_t initial_gid;

/* what user is current? */
extern struct current_user current_user;

pstring OriginalDir;

/****************************************************************************
initialise the uid routines
****************************************************************************/
void init_uid(void)
{
	initial_uid = current_user.uid = geteuid();
	initial_gid = current_user.gid = getegid();

	if (initial_gid != 0 && initial_uid == 0) {
#ifdef HAVE_SETRESUID
		setresgid(0,0,0);
#else
		setgid(0);
		setegid(0);
#endif
	}

	initial_uid = geteuid();
	initial_gid = getegid();

	current_user.conn = NULL;
	current_user.vuid = UID_FIELD_INVALID;
	
	dos_ChDir(OriginalDir);
}


/****************************************************************************
  become the specified uid 
****************************************************************************/
static BOOL become_uid(uid_t uid)
{
	if (initial_uid != 0) {
		return(True);
	}
	
	if (uid == (uid_t)-1 || ((sizeof(uid_t) == 2) && (uid == (uid_t)65535))) {
		static int done;
		if (!done) {
			DEBUG(1,("WARNING: using uid %d is a security risk\n",(int)uid));
			done=1;
		}
	}

#ifdef HAVE_TRAPDOOR_UID
#ifdef HAVE_SETUIDX
	/* AIX3 has setuidx which is NOT a trapoor function (tridge) */
	if (setuidx(ID_EFFECTIVE, uid) != 0) {
		if (seteuid(uid) != 0) {
			DEBUG(1,("Can't set uid %d (setuidx)\n", (int)uid));
			return False;
		}
	}
#endif
#endif

#ifdef HAVE_SETRESUID
    if (setresuid(-1,uid,-1) != 0)
#else
    if ((seteuid(uid) != 0) && 
	(setuid(uid) != 0))
#endif
      {
	DEBUG(0,("Couldn't set uid %d currently set to (%d,%d)\n",
		 (int)uid,(int)getuid(), (int)geteuid()));
	if (uid > (uid_t)32000) {
		DEBUG(0,("Looks like your OS doesn't like high uid values - try using a different account\n"));
	}
	return(False);
      }

    if (((uid == (uid_t)-1) || ((sizeof(uid_t) == 2) && (uid == 65535))) && (geteuid() != uid)) {
	    DEBUG(0,("Invalid uid -1. perhaps you have a account with uid 65535?\n"));
	    return(False);
    }

    current_user.uid = uid;

    return(True);
}


/****************************************************************************
  become the specified gid
****************************************************************************/
static BOOL become_gid(gid_t gid)
{
  if (initial_uid != 0)
    return(True);

  if (gid == (gid_t)-1 || ((sizeof(gid_t) == 2) && (gid == (gid_t)65535))) {
    DEBUG(1,("WARNING: using gid %d is a security risk\n",(int)gid));    
  }
  
#ifdef HAVE_SETRESUID
  if (setresgid(-1,gid,-1) != 0)
#else
  if (setgid(gid) != 0)
#endif
      {
	DEBUG(0,("Couldn't set gid %d currently set to (%d,%d)\n",
		 (int)gid,(int)getgid(),(int)getegid()));
	if (gid > 32000) {
		DEBUG(0,("Looks like your OS doesn't like high gid values - try using a different account\n"));
	}
	return(False);
      }

  current_user.gid = gid;

  return(True);
}


/****************************************************************************
  become the specified uid and gid
****************************************************************************/
static BOOL become_id(uid_t uid,gid_t gid)
{
	return(become_gid(gid) && become_uid(uid));
}

/****************************************************************************
become the guest user
****************************************************************************/
BOOL become_guest(void)
{
  BOOL ret;
  static struct passwd *pass=NULL;

  if (initial_uid != 0) 
    return(True);

  if (!pass)
    pass = Get_Pwnam(lp_guestaccount(-1),True);
  if (!pass) return(False);

#ifdef AIX
  /* MWW: From AIX FAQ patch to WU-ftpd: call initgroups before setting IDs */
  initgroups(pass->pw_name, (gid_t)pass->pw_gid);
#endif

  ret = become_id(pass->pw_uid,pass->pw_gid);

  if (!ret) {
    DEBUG(1,("Failed to become guest. Invalid guest account?\n"));
  }

  current_user.conn = NULL;
  current_user.vuid = UID_FIELD_INVALID;

  return(ret);
}

/*******************************************************************
check if a username is OK
********************************************************************/
static BOOL check_user_ok(connection_struct *conn, user_struct *vuser,int snum)
{
  int i;
  for (i=0;i<conn->uid_cache.entries;i++)
    if (conn->uid_cache.list[i] == vuser->uid) return(True);

  if (!user_ok(vuser->name,snum)) return(False);

  i = conn->uid_cache.entries % UID_CACHE_SIZE;
  conn->uid_cache.list[i] = vuser->uid;

  if (conn->uid_cache.entries < UID_CACHE_SIZE)
    conn->uid_cache.entries++;

  return(True);
}


/****************************************************************************
  become the user of a connection number
****************************************************************************/
BOOL become_user(connection_struct *conn, uint16 vuid)
{
	user_struct *vuser = get_valid_user_struct(vuid);
	int snum;
    gid_t gid;
	uid_t uid;

	/*
	 * We need a separate check in security=share mode due to vuid
	 * always being UID_FIELD_INVALID. If we don't do this then
	 * in share mode security we are *always* changing uid's between
	 * SMB's - this hurts performance - Badly.
	 */

	if((lp_security() == SEC_SHARE) && (current_user.conn == conn) &&
	   (current_user.uid == conn->uid)) {
		DEBUG(4,("Skipping become_user - already user\n"));
		return(True);
	} else if ((current_user.conn == conn) && 
		   (vuser != 0) && (current_user.vuid == vuid) && 
		   (current_user.uid == vuser->uid)) {
		DEBUG(4,("Skipping become_user - already user\n"));
		return(True);
	}

	unbecome_user();

	if (!conn) {
		DEBUG(2,("Connection not open\n"));
		return(False);
	}

	snum = SNUM(conn);

	if((vuser != NULL) && !check_user_ok(conn, vuser, snum))
		return False;

	if (conn->force_user || 
	    lp_security() == SEC_SHARE ||
	    !(vuser) || (vuser->guest)) {
		uid = conn->uid;
		gid = conn->gid;
		current_user.groups = conn->groups;
		current_user.ngroups = conn->ngroups;
	} else {
		if (!vuser) {
			DEBUG(2,("Invalid vuid used %d\n",vuid));
			return(False);
		}
		uid = vuser->uid;
		if(!*lp_force_group(snum)) {
			gid = vuser->gid;
		} else {
			gid = conn->gid;
		}
		current_user.ngroups = vuser->n_groups;
		current_user.groups  = vuser->groups;
	}
	
	if (initial_uid == 0)  {
		if (!become_gid(gid)) return(False);

#ifdef HAVE_SETGROUPS      
		if (!(conn && conn->ipc)) {
			/* groups stuff added by ih/wreu */
			if (current_user.ngroups > 0)
				if (setgroups(current_user.ngroups,
					      current_user.groups)<0) {
					DEBUG(0,("setgroups call failed!\n"));
				}
		}
#endif

		if (!conn->admin_user && !become_uid(uid))
			return(False);
	}
	
	current_user.conn = conn;
	current_user.vuid = vuid;

	DEBUG(5,("become_user uid=(%d,%d) gid=(%d,%d)\n",
		 (int)getuid(),(int)geteuid(),(int)getgid(),(int)getegid()));
  
	return(True);
}

/****************************************************************************
  unbecome the user of a connection number
****************************************************************************/
BOOL unbecome_user(void )
{
  if (!current_user.conn)
    return(False);

  dos_ChDir(OriginalDir);

  if (initial_uid == 0)
    {
#ifdef HAVE_SETRESUID
      setresuid(-1,getuid(),-1);
      setresgid(-1,getgid(),-1);
#else
      if (seteuid(initial_uid) != 0) 
	setuid(initial_uid);
      setgid(initial_gid);
#endif
    }

#ifdef NO_EID
  if (initial_uid == 0)
    DEBUG(2,("Running with no EID\n"));
  initial_uid = getuid();
  initial_gid = getgid();
#else
  if (geteuid() != initial_uid) {
	  DEBUG(0,("Warning: You appear to have a trapdoor uid system\n"));
	  initial_uid = geteuid();
  }
  if (getegid() != initial_gid) {
	  DEBUG(0,("Warning: You appear to have a trapdoor gid system\n"));
	  initial_gid = getegid();
  }
#endif

  current_user.uid = initial_uid;
  current_user.gid = initial_gid;
  
  if (dos_ChDir(OriginalDir) != 0)
    DEBUG( 0, ( "chdir(%s) failed in unbecome_user\n", OriginalDir ) );

  DEBUG(5,("unbecome_user now uid=(%d,%d) gid=(%d,%d)\n",
	(int)getuid(),(int)geteuid(),(int)getgid(),(int)getegid()));

  current_user.conn = NULL;
  current_user.vuid = UID_FIELD_INVALID;

  return(True);
}

static struct current_user current_user_saved;
static int become_root_depth;
static pstring become_root_dir;

/****************************************************************************
This is used when we need to do a privilaged operation (such as mucking
with share mode files) and temporarily need root access to do it. This
call should always be paired with an unbecome_root() call immediately
after the operation

Set save_dir if you also need to save/restore the CWD 
****************************************************************************/
void become_root(BOOL save_dir) 
{
	if (become_root_depth) {
		DEBUG(0,("ERROR: become root depth is non zero\n"));
	}
	if (save_dir)
		dos_GetWd(become_root_dir);

	current_user_saved = current_user;
	become_root_depth = 1;

	become_uid(0);
	become_gid(0);
}

/****************************************************************************
When the privilaged operation is over call this

Set save_dir if you also need to save/restore the CWD 
****************************************************************************/
void unbecome_root(BOOL restore_dir)
{
	if (become_root_depth != 1) {
		DEBUG(0,("ERROR: unbecome root depth is %d\n",
			 become_root_depth));
	}

	/* we might have done a become_user() while running as root,
	   if we have then become root again in order to become 
	   non root! */
	if (current_user.uid != 0) {
		become_uid(0);
	}

	/* restore our gid first */
	if (!become_gid(current_user_saved.gid)) {
		DEBUG(0,("ERROR: Failed to restore gid\n"));
		exit_server("Failed to restore gid");
	}

#ifdef HAVE_SETGROUPS      
	if (current_user_saved.ngroups > 0) {
		if (setgroups(current_user_saved.ngroups,
			      current_user_saved.groups)<0)
			DEBUG(0,("ERROR: setgroups call failed!\n"));
	}
#endif

	/* now restore our uid */
	if (!become_uid(current_user_saved.uid)) {
		DEBUG(0,("ERROR: Failed to restore uid\n"));
		exit_server("Failed to restore uid");
	}

	if (restore_dir)
		dos_ChDir(become_root_dir);

	current_user = current_user_saved;

	become_root_depth = 0;
}