File: accesscheck.c

package info (click to toggle)
dante 1.4.2%2Bdfsg-7
  • links: PTS, VCS
  • area: main
  • in suites: bookworm, bullseye, sid, trixie
  • size: 11,640 kB
  • sloc: ansic: 64,514; sh: 11,180; yacc: 3,127; lex: 1,683; makefile: 364; awk: 220
file content (424 lines) | stat: -rw-r--r-- 13,311 bytes parent folder | download | duplicates (4)
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
/*
 * Copyright (c) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2005, 2006, 2008,
 *               2009, 2010, 2011, 2012, 2013
 *      Inferno Nettverk A/S, Norway.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. The above copyright notice, this list of conditions and the following
 *    disclaimer must appear in all copies of the software, derivative works
 *    or modified versions, and any portions thereof, aswell as in all
 *    supporting documentation.
 * 2. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by
 *      Inferno Nettverk A/S, Norway.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Inferno Nettverk A/S requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  sdc@inet.no
 *  Inferno Nettverk A/S
 *  Oslo Research Park
 *  Gaustadallen 21
 *  NO-0349 Oslo
 *  Norway
 *
 * any improvements or extensions that they make and grant Inferno Nettverk A/S
 * the rights to redistribute these changes.
 *
 */

#include "common.h"

static const char rcsid[] =
"$Id: accesscheck.c,v 1.89 2013/10/27 15:24:42 karls Exp $";

int
usermatch(auth, userlist)
   const authmethod_t *auth;
   const linkedname_t *userlist;
{
/*   const char *function = "usermatch()"; */
   const char *name;

   if ((name = authname(auth)) == NULL)
      return 0; /* no username, no match. */

   do
      if (strcmp(name, userlist->name) == 0)
         break;
   while ((userlist = userlist->next) != NULL);

   if (userlist == NULL)
      return 0; /* no match. */
   return 1;
}

int
groupmatch(auth, grouplist)
   const authmethod_t *auth;
   const linkedname_t *grouplist;
{
   const char *function = "groupmatch()";
   const char *username;
   struct passwd *pw;
   struct group *groupent;

   SASSERTX(grouplist != NULL);

   if ((username = authname(auth)) == NULL)
      return 0; /* no username, no match. */

   /*
    * First check the primary group of the user against grouplist.
    * If the groupname given there matches, we don't need to go through
    * all users in the list of group.
    */
   if ((pw = getpwnam(username))         != NULL
   &&  (groupent = getgrgid(pw->pw_gid)) != NULL) {
      const linkedname_t *listent = grouplist;

      do
         if (strcmp(groupent->gr_name, listent->name) == 0)
            return 1;
      while ((listent = listent->next) != NULL);
   }
   else {
      if (pw == NULL)
         slog(LOG_DEBUG, "%s: unknown username \"%s\"", function, username);
      else if (groupent == NULL)
         slog(LOG_DEBUG, "%s: unknown primary groupid %ld",
              function, (long)pw->pw_gid);
   }

   /*
    * Go through grouplist, matching username against each groupmember of
    * all the groups in grouplist.
    */
   do {
      char **groupname;

      if ((groupent = getgrnam(grouplist->name)) == NULL) {
         swarn("%s: unknown groupname \"%s\"", function, grouplist->name);
         continue;
      }

      groupname = groupent->gr_mem;

      while (*groupname != NULL) {
         if (strcmp(username, *groupname) == 0)
            return 1; /* match. */

         ++groupname;
      }
   } while ((grouplist = grouplist->next) != NULL);

   return 0;
}

#if HAVE_LDAP
int
ldapgroupmatch(auth, rule)
   const authmethod_t *auth;
   const rule_t *rule;
{
   const char *function = "ldapgroupmatch()";
   const linkedname_t *grouplist;
   const char *username;
   char *userdomain, *groupdomain;
   int retval;

   if ((username = authname(auth)) == NULL)
      return 0; /* no username, no match. */

#if !HAVE_GSSAPI
   if (!rule->state.ldap.ldapurl)
      SERRX(rule->state.ldap.ldapurl != NULL);
#endif /* !HAVE_GSSAPI */

   if ((userdomain = strchr(username, '@')) != NULL)
      ++userdomain;

   if (userdomain == NULL && *rule->state.ldap.domain == NUL && rule->state.ldap.ldapurl == NULL) {
      slog(LOG_DEBUG, "%s: cannot check ldap group membership for user %s: "
                      "user has no domain postfix and no ldap url is defined",
                      function, username);
      return 0;
   }

   if ((retval = ldap_user_is_cached(username)) >= 0)
      return retval;

   /* go through grouplist, matching username against members of each group. */
   grouplist = rule->ldapgroup;
   do {
      char groupname[MAXNAMELEN];

      slog(LOG_DEBUG, "%s: checking if user %s is member of ldap group %s",
                      function, username, grouplist->name);

      STRCPY_ASSERTLEN(groupname, grouplist->name);

      if ((groupdomain = strchr(groupname, '@')) != NULL) {
         *groupdomain = NUL; /* separates groupname from groupdomain. */
         ++groupdomain;
      }

      if (groupdomain != NULL && userdomain != NULL) {
         if (strcmp(groupdomain, userdomain) != 0
         &&  strcmp(groupdomain, "") != 0) {
            slog(LOG_DEBUG, "%s: userdomain \"%s\" does not match groupdomain "
                            "\"%s\" and groupdomain is not default domain.  "
                            "Trying next entry",
                            function, userdomain, groupdomain);
            continue;
         }
      }

      if (ldapgroupmatches(username, userdomain, groupname, groupdomain, rule)){
         cache_ldap_user(username, 1);
         return 1;
      }
   } while ((grouplist = grouplist->next) != NULL);

   cache_ldap_user(username, 0);
   return 0;
}
#endif /* HAVE_LDAP */

int
accesscheck(s, auth, src, dst, emsg, emsgsize)
   int s;
   authmethod_t *auth;
   const struct sockaddr_storage *src, *dst;
   char *emsg;
   size_t emsgsize;
{
   const char *function = "accesscheck()";
   char srcstr[MAXSOCKADDRSTRING], dststr[sizeof(srcstr)];
   int match, authresultisfixed;

   if (sockscf.option.debug)
      slog(LOG_DEBUG, "%s: method: %s, %s -> %s ",
           function,
           method2string(auth->method),
           src == NULL ?
                  "<unknown>" : sockaddr2string(src, srcstr, sizeof(srcstr)),
            dst == NULL ?
                 "<unknown>"  : sockaddr2string(dst, dststr, sizeof(dststr)));

   /*
    * We don't want to re-check the same method.  This could
    * happen in several cases:
    *  - was checked as client-rule, is now checked as socks-rule.
    *  - a different rule with the same method.  The client is however
    *    the same, so if the auth for method 'k' failed in previous rule,
    *    it will fail the next time also.
   */

   if (methodisset(auth->method, auth->methodv, (size_t)auth->methodc)) {
      slog(LOG_DEBUG, "%s: method %s already checked, matches",
           function, method2string(auth->method));

      return 1; /* already checked, matches. */
   }

   if (methodisset(auth->method, auth->badmethodv, (size_t)auth->badmethodc)) {
      snprintf(emsg, emsgsize,
              "authentication provided by client for method \"%s\" "
              "does not match",
              method2string(auth->method));

      slog(LOG_DEBUG, "%s: method %s already checked, does not match",
           function, method2string(auth->method));

      return 0; /* already checked, won't match. */
   }

   match = 0;

   switch (auth->method) {
      /*
       * Methods where no further checking is done at this point, either
       * because there's nothing to check, or it has already been checked.
       */
      case AUTHMETHOD_NONE:
#if HAVE_GSSAPI
      case AUTHMETHOD_GSSAPI:
#endif /* HAVE_GSSAPI */
         match = 1;
         break;

      case AUTHMETHOD_UNAME:
         if (passwordcheck((const char *)auth->mdata.uname.name,
                           (const char *)auth->mdata.uname.password,
                           emsg,
                           emsgsize) == 0)
            match = 1;

         break;

#if HAVE_LIBWRAP
      case AUTHMETHOD_RFC931:
         if (passwordcheck((const char *)auth->mdata.rfc931.name,
                           NULL,
                           emsg,
                           emsgsize) == 0)
            match = 1;
         break;
#endif /* HAVE_LIBWRAP */

#if HAVE_PAM
      case AUTHMETHOD_PAM_ANY:
      case AUTHMETHOD_PAM_ADDRESS:
      case AUTHMETHOD_PAM_USERNAME: {
#if DIAGNOSTIC
         const int freec
         = freedescriptors(sockscf.option.debug ?  "start" : NULL, NULL);
#endif /* DIAGNOSTIC */

         if (pam_passwordcheck(s,
                               src,
                               dst,
                               &auth->mdata.pam,
                               emsg,
                               emsgsize) == 0)
            match = 1;

#if DIAGNOSTIC
         if (freec
         != freedescriptors(sockscf.option.debug ? "end" : NULL, NULL))
            swarnx("%s: lost %d file descriptor%s in pam_passwordcheck()",
                   function,
                   freec - freedescriptors(NULL, NULL),
                   freec - freedescriptors(NULL, NULL) == 1 ? "" : "s");
#endif /* DIAGNOSTIC */

         break;
      }
#endif /* HAVE_PAM */

#if HAVE_BSDAUTH
      case AUTHMETHOD_BSDAUTH: {
#if DIAGNOSTIC
         const int freec
         = freedescriptors(sockscf.option.debug ?  "start" : NULL, NULL);
#endif /* DIAGNOSTIC */

         if (bsdauth_passwordcheck(s,
                                   src,
                                   dst,
                                   &auth->mdata.bsd,
                                   emsg,
                                   emsgsize) == 0)
            match = 1;

#if DIAGNOSTIC
         if (freec
         != freedescriptors(sockscf.option.debug ?  "end" : NULL, NULL))
            swarnx("%s: lost %d file descriptor%s in bsdauth_passwordcheck()",
                   function,
                   freec - freedescriptors(NULL, NULL),
                   freec - freedescriptors(NULL, NULL) == 1 ? "" : "s");
#endif /* DIAGNOSTIC */
         break;
      }
#endif /* HAVE_BSDAUTH */

      default:
         SERRX(auth->method);
   }

   /*
    * Some methods can be called with different values for the
    * same client, based on values configured in the rules.
    * Others cannot and we want to mark those that cannot as
    * "tried", so we don't waste time on re-trying them.
    */
   switch (auth->method) {
#if HAVE_PAM
      case AUTHMETHOD_PAM_ANY:
      case AUTHMETHOD_PAM_ADDRESS:
      case AUTHMETHOD_PAM_USERNAME:
         if (*sockscf.state.pamservicename == NUL)
            authresultisfixed = 0;
         else
            authresultisfixed = 1;
         break;
#endif /* HAVE_PAM */

#if HAVE_BSDAUTH
   case AUTHMETHOD_BSDAUTH:
         if (sockscf.state.bsdauthstylename == NULL)
            authresultisfixed = 0;
         else
            authresultisfixed = 1;
         break;
#endif /* HAVE_PAM */

#if HAVE_GSSAPI
      case AUTHMETHOD_GSSAPI:
         if (*sockscf.state.gssapiservicename == NUL
         ||  *sockscf.state.gssapikeytab      == NUL)
            authresultisfixed = 0;
         else
            authresultisfixed = 1;
         break;
#endif /* HAVE_GSSAPI */

      case AUTHMETHOD_NONE:
      case AUTHMETHOD_UNAME:
      case AUTHMETHOD_RFC931:
         authresultisfixed = 1;
         break;

      default:
         SERRX(auth->method);
   }

   if (authresultisfixed) {
      if (match) {
         SASSERTX(auth->methodc + 1 <= ELEMENTS(auth->methodv));
         auth->methodv[auth->methodc++] = auth->method;
      }
      else {
         SASSERTX(auth->badmethodc + 1 <= ELEMENTS(auth->badmethodv));
         auth->badmethodv[auth->badmethodc++] = auth->method;
      }

      /*
       * Unfortunately we can not bzero() the password for several reasons:
       * 1) If UDP, perhaps packets to different targets will require different
       *    authentication.  E.g. username was used when establishing the
       *    control-connection, while pam is used when sending packets to
       *    certain targets.  Unlikely, but not impossible.
       *
       * 2) If we are forwarding to an upstream proxy that we are
       *    configured to offer the username/password from the user.
       */
   }

   if (match)
      slog(LOG_DEBUG, "%s: authentication matched", function);
   else
      slog(LOG_DEBUG, "%s: no match for authentication%s %s",
           function,
           emsgsize > 0 ? ":"  : "",
           emsgsize > 0 ? emsg : "");

   return match;
}