lib/libcr/rpc/svc_auth_des.c

   1
   2 /*
   3  * Copyright (c) 1988 by Sun Microsystems, Inc.
   4  */
   5
   6 /*
   7  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   8  * unrestricted use provided that this legend is included on all tape
   9  * media and as a part of the software program in whole or part.  Users
  10  * may copy or modify Sun RPC without charge, but are not authorized
  11  * to license or distribute it to anyone else except as part of a product or
  12  * program developed by the user.
  13  *
  14  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  15  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  17  *
  18  * Sun RPC is provided with no support and without any obligation on the
  19  * part of Sun Microsystems, Inc. to assist in its use, correction,
  20  * modification or enhancement.
  21  *
  22  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  23  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  24  * OR ANY PART THEREOF.
  25  *
  26  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  27  * or profits or other special, indirect and consequential damages, even if
  28  * Sun has been advised of the possibility of such damages.
  29  *
  30  * Sun Microsystems, Inc.
  31  * 2550 Garcia Avenue
  32  * Mountain View, California  94043
  33  */
  34
  35 /*
  36  * svcauth_des.c, server-side des authentication
  37  *
  38  * We insure for the service the following:
  39  * (1) The timestamp microseconds do not exceed 1 million.
  40  * (2) The timestamp plus the window is less than the current time.
  41  * (3) The timestamp is not less than the one previously
  42  *     seen in the current session.
  43  *
  44  * It is up to the server to determine if the window size is
  45  * too small .
  46  *
  47  */
  48
  49 #include <string.h>
  50 #include <stdlib.h>
  51 #include <unistd.h>
  52 #include <rpc/des_crypt.h>
  53 #include <sys/param.h>
  54 #include <netinet/in.h>
  55 #include <rpc/types.h>
  56 #include <rpc/xdr.h>
  57 #include <rpc/auth.h>
  58 #include <rpc/auth_des.h>
  59 #include <rpc/svc.h>
  60 #include <rpc/rpc_msg.h>
  61 #include <rpc/svc_auth.h>
  62
  63 #if defined(LIBC_SCCS) && !defined(lint)
  64 /* from: static char sccsid[] =         "@(#)svcauth_des.c      2.3 89/07/11 4.0 RPCSRC; from 1.15 88/02/08 SMI"; */
  65 static const char rcsid[] = "$FreeBSD: src/lib/libc/rpc/svc_auth_des.c,v 1.3 1999/08/28 00:00:48 peter Exp $";
  66 #endif
  67
  68 #define debug(msg)       printf("svcauth_des: %s\n", msg)
  69
  70 #define USEC_PER_SEC ((u_long) 1000000L)
  71 #define BEFORE(t1, t2) timercmp(t1, t2, <)
  72
  73 /*
  74  * LRU cache of conversation keys and some other useful items.
  75  */
  76 #define AUTHDES_CACHESZ 64
  77 struct cache_entry {
  78         des_block key;          /* conversation key */
  79         char *rname;            /* client's name */
  80         u_int window;           /* credential lifetime window */
  81         struct timeval laststamp;       /* detect replays of creds */
  82         char *localcred;        /* generic local credential */
  83 };
  84 static struct cache_entry *authdes_cache/* [AUTHDES_CACHESZ] */;
  85 static short *authdes_lru/* [AUTHDES_CACHESZ] */;
  86
  87 static void cache_init();       /* initialize the cache */
  88 static short cache_spot();      /* find an entry in the cache */
  89 static void cache_ref(/*short sid*/);   /* note that sid was ref'd */
  90
  91 static void invalidate();       /* invalidate entry in cache */
  92
  93 /*
  94  * cache statistics
  95  */
  96 static struct {
  97         u_long ncachehits;      /* times cache hit, and is not replay */
  98         u_long ncachereplays;   /* times cache hit, and is replay */
  99         u_long ncachemisses;    /* times cache missed */
 100 } svcauthdes_stats;
 101
 102 /*
 103  * Service side authenticator for AUTH_DES
 104  */
 105 enum auth_stat
 106 _svcauth_des(rqst, msg)
 107         register struct svc_req *rqst;
 108         register struct rpc_msg *msg;
 109 {
 110
 111         register long *ixdr;
 112         des_block cryptbuf[2];
 113         register struct authdes_cred *cred;
 114         struct authdes_verf verf;
 115         int status;
 116         register struct cache_entry *entry;
 117         short sid = 0;
 118         des_block *sessionkey;
 119         des_block ivec;
 120         u_int window;
 121         struct timeval timestamp;
 122         u_long namelen;
 123         struct area {
 124                 struct authdes_cred area_cred;
 125                 char area_netname[MAXNETNAMELEN+1];
 126         } *area;
 127
 128         if (authdes_cache == NULL) {
 129                 cache_init();
 130         }
 131
 132         area = (struct area *)rqst->rq_clntcred;
 133         cred = (struct authdes_cred *)&area->area_cred;
 134
 135         /*
 136          * Get the credential
 137          */
 138         ixdr = (long *)msg->rm_call.cb_cred.oa_base;
 139         cred->adc_namekind = IXDR_GET_ENUM(ixdr, enum authdes_namekind);
 140         switch (cred->adc_namekind) {
 141         case ADN_FULLNAME:
 142                 namelen = IXDR_GET_U_LONG(ixdr);
 143                 if (namelen > MAXNETNAMELEN) {
 144                         return (AUTH_BADCRED);
 145                 }
 146                 cred->adc_fullname.name = area->area_netname;
 147                 bcopy((char *)ixdr, cred->adc_fullname.name,
 148                         (u_int)namelen);
 149                 cred->adc_fullname.name[namelen] = 0;
 150                 ixdr += (RNDUP(namelen) / BYTES_PER_XDR_UNIT);
 151                 cred->adc_fullname.key.key.high = (u_long)*ixdr++;
 152                 cred->adc_fullname.key.key.low = (u_long)*ixdr++;
 153                 cred->adc_fullname.window = (u_long)*ixdr++;
 154                 break;
 155         case ADN_NICKNAME:
 156                 cred->adc_nickname = (u_long)*ixdr++;
 157                 break;
 158         default:
 159                 return (AUTH_BADCRED);
 160         }
 161
 162         /*
 163          * Get the verifier
 164          */
 165         ixdr = (long *)msg->rm_call.cb_verf.oa_base;
 166         verf.adv_xtimestamp.key.high = (u_long)*ixdr++;
 167         verf.adv_xtimestamp.key.low =  (u_long)*ixdr++;
 168         verf.adv_int_u = (u_long)*ixdr++;
 169
 170
 171         /*
 172          * Get the conversation key
 173          */
 174         if (cred->adc_namekind == ADN_FULLNAME) {
 175                 netobj pkey;
 176                 char pkey_data[1024];
 177
 178                 sessionkey = &cred->adc_fullname.key;
 179                 if (! getpublickey(cred->adc_fullname.name, pkey_data)) {
 180                         debug("getpublickey");
 181                         return(AUTH_BADCRED);
 182                 }
 183                 pkey.n_bytes = pkey_data;
 184                 pkey.n_len = strlen(pkey_data) + 1;
 185                 if (key_decryptsession_pk(cred->adc_fullname.name, &pkey,
 186                                        sessionkey) < 0) {
 187                         debug("decryptsessionkey");
 188                         return (AUTH_BADCRED); /* key not found */
 189                 }
 190         } else { /* ADN_NICKNAME */
 191                 sid = (short)cred->adc_nickname;
 192                 if (sid >= AUTHDES_CACHESZ) {
 193                         debug("bad nickname");
 194                         return (AUTH_BADCRED);  /* garbled credential */
 195                 }
 196                 sessionkey = &authdes_cache[sid].key;
 197         }
 198
 199
 200         /*
 201          * Decrypt the timestamp
 202          */
 203         cryptbuf[0] = verf.adv_xtimestamp;
 204         if (cred->adc_namekind == ADN_FULLNAME) {
 205                 cryptbuf[1].key.high = cred->adc_fullname.window;
 206                 cryptbuf[1].key.low = verf.adv_winverf;
 207                 ivec.key.high = ivec.key.low = 0;
 208                 status = cbc_crypt((char *)sessionkey, (char *)cryptbuf,
 209                         2*sizeof(des_block), DES_DECRYPT | DES_HW,
 210                         (char *)&ivec);
 211         } else {
 212                 status = ecb_crypt((char *)sessionkey, (char *)cryptbuf,
 213                         sizeof(des_block), DES_DECRYPT | DES_HW);
 214         }
 215         if (DES_FAILED(status)) {
 216                 debug("decryption failure");
 217                 return (AUTH_FAILED);   /* system error */
 218         }
 219
 220         /*
 221          * XDR the decrypted timestamp
 222          */
 223         ixdr = (long *)cryptbuf;
 224         timestamp.tv_sec = IXDR_GET_LONG(ixdr);
 225         timestamp.tv_usec = IXDR_GET_LONG(ixdr);
 226
 227         /*
 228          * Check for valid credentials and verifiers.
 229          * They could be invalid because the key was flushed
 230          * out of the cache, and so a new session should begin.
 231          * Be sure and send AUTH_REJECTED{CRED, VERF} if this is the case.
 232          */
 233         {
 234                 struct timeval current;
 235                 int nick;
 236                 int winverf;
 237
 238                 if (cred->adc_namekind == ADN_FULLNAME) {
 239                         window = IXDR_GET_U_LONG(ixdr);
 240                         winverf = IXDR_GET_U_LONG(ixdr);
 241                         if (winverf != window - 1) {
 242                                 debug("window verifier mismatch");
 243                                 return (AUTH_BADCRED);  /* garbled credential */
 244                         }
 245                         sid = cache_spot(sessionkey, cred->adc_fullname.name,
 246                             &timestamp);
 247                         if (sid < 0) {
 248                                 debug("replayed credential");
 249                                 return (AUTH_REJECTEDCRED);     /* replay */
 250                         }
 251                         nick = 0;
 252                 } else {        /* ADN_NICKNAME */
 253                         window = authdes_cache[sid].window;
 254                         nick = 1;
 255                 }
 256
 257                 if ((u_long)timestamp.tv_usec >= USEC_PER_SEC) {
 258                         debug("invalid usecs");
 259                         /* cached out (bad key), or garbled verifier */
 260                         return (nick ? AUTH_REJECTEDVERF : AUTH_BADVERF);
 261                 }
 262                 if (nick && BEFORE(&timestamp,
 263                                    &authdes_cache[sid].laststamp)) {
 264                         debug("timestamp before last seen");
 265                         return (AUTH_REJECTEDVERF);     /* replay */
 266                 }
 267                 (void) gettimeofday(&current, (struct timezone *)NULL);
 268                 current.tv_sec -= window;       /* allow for expiration */
 269                 if (!BEFORE(&current, &timestamp)) {
 270                         debug("timestamp expired");
 271                         /* replay, or garbled credential */
 272                         return (nick ? AUTH_REJECTEDVERF : AUTH_BADCRED);
 273                 }
 274         }
 275
 276         /*
 277          * Set up the reply verifier
 278          */
 279         verf.adv_nickname = (u_long)sid;
 280
 281         /*
 282          * xdr the timestamp before encrypting
 283          */
 284         ixdr = (long *)cryptbuf;
 285         IXDR_PUT_LONG(ixdr, timestamp.tv_sec - 1);
 286         IXDR_PUT_LONG(ixdr, timestamp.tv_usec);
 287
 288         /*
 289          * encrypt the timestamp
 290          */
 291         status = ecb_crypt((char *)sessionkey, (char *)cryptbuf,
 292             sizeof(des_block), DES_ENCRYPT | DES_HW);
 293         if (DES_FAILED(status)) {
 294                 debug("encryption failure");
 295                 return (AUTH_FAILED);   /* system error */
 296         }
 297         verf.adv_xtimestamp = cryptbuf[0];
 298
 299         /*
 300          * Serialize the reply verifier, and update rqst
 301          */
 302         ixdr = (long *)msg->rm_call.cb_verf.oa_base;
 303         *ixdr++ = (long)verf.adv_xtimestamp.key.high;
 304         *ixdr++ = (long)verf.adv_xtimestamp.key.low;
 305         *ixdr++ = (long)verf.adv_int_u;
 306
 307         rqst->rq_xprt->xp_verf.oa_flavor = AUTH_DES;
 308         rqst->rq_xprt->xp_verf.oa_base = msg->rm_call.cb_verf.oa_base;
 309         rqst->rq_xprt->xp_verf.oa_length =
 310                 (char *)ixdr - msg->rm_call.cb_verf.oa_base;
 311
 312         /*
 313          * We succeeded, commit the data to the cache now and
 314          * finish cooking the credential.
 315          */
 316         entry = &authdes_cache[sid];
 317         entry->laststamp = timestamp;
 318         cache_ref(sid);
 319         if (cred->adc_namekind == ADN_FULLNAME) {
 320                 cred->adc_fullname.window = window;
 321                 cred->adc_nickname = (u_long)sid;       /* save nickname */
 322                 if (entry->rname != NULL) {
 323                         mem_free(entry->rname, strlen(entry->rname) + 1);
 324                 }
 325                 entry->rname = (char *)mem_alloc((u_int)strlen(cred->adc_fullname.name)
 326                                          + 1);
 327                 if (entry->rname != NULL) {
 328                         (void) strcpy(entry->rname, cred->adc_fullname.name);
 329                 } else {
 330                         debug("out of memory");
 331                 }
 332                 entry->key = *sessionkey;
 333                 entry->window = window;
 334                 invalidate(entry->localcred); /* mark any cached cred invalid */
 335         } else { /* ADN_NICKNAME */
 336                 /*
 337                  * nicknames are cooked into fullnames
 338                  */
 339                 cred->adc_namekind = ADN_FULLNAME;
 340                 cred->adc_fullname.name = entry->rname;
 341                 cred->adc_fullname.key = entry->key;
 342                 cred->adc_fullname.window = entry->window;
 343         }
 344         return (AUTH_OK);       /* we made it!*/
 345 }
 346
 347
 348 /*
 349  * Initialize the cache
 350  */
 351 static void
 352 cache_init()
 353 {
 354         register int i;
 355
 356         authdes_cache = (struct cache_entry *)
 357                 mem_alloc(sizeof(struct cache_entry) * AUTHDES_CACHESZ);
 358         bzero((char *)authdes_cache,
 359                 sizeof(struct cache_entry) * AUTHDES_CACHESZ);
 360
 361         authdes_lru = (short *)mem_alloc(sizeof(short) * AUTHDES_CACHESZ);
 362         /*
 363          * Initialize the lru list
 364          */
 365         for (i = 0; i < AUTHDES_CACHESZ; i++) {
 366                 authdes_lru[i] = i;
 367         }
 368 }
 369
 370
 371 /*
 372  * Find the lru victim
 373  */
 374 static short
 375 cache_victim()
 376 {
 377         return (authdes_lru[AUTHDES_CACHESZ-1]);
 378 }
 379
 380 /*
 381  * Note that sid was referenced
 382  */
 383 static void
 384 cache_ref(sid)
 385         register short sid;
 386 {
 387         register int i;
 388         register short curr;
 389         register short prev;
 390
 391         prev = authdes_lru[0];
 392         authdes_lru[0] = sid;
 393         for (i = 1; prev != sid; i++) {
 394                 curr = authdes_lru[i];
 395                 authdes_lru[i] = prev;
 396                 prev = curr;
 397         }
 398 }
 399
 400
 401 /*
 402  * Find a spot in the cache for a credential containing
 403  * the items given.  Return -1 if a replay is detected, otherwise
 404  * return the spot in the cache.
 405  */
 406 static short
 407 cache_spot(key, name, timestamp)
 408         register des_block *key;
 409         char *name;
 410         struct timeval *timestamp;
 411 {
 412         register struct cache_entry *cp;
 413         register int i;
 414         register u_long hi;
 415
 416         hi = key->key.high;
 417         for (cp = authdes_cache, i = 0; i < AUTHDES_CACHESZ; i++, cp++) {
 418                 if (cp->key.key.high == hi &&
 419                     cp->key.key.low == key->key.low &&
 420                     cp->rname != NULL &&
 421                     bcmp(cp->rname, name, strlen(name) + 1) == 0) {
 422                         if (BEFORE(timestamp, &cp->laststamp)) {
 423                                 svcauthdes_stats.ncachereplays++;
 424                                 return (-1); /* replay */
 425                         }
 426                         svcauthdes_stats.ncachehits++;
 427                         return (i);     /* refresh */
 428                 }
 429         }
 430         svcauthdes_stats.ncachemisses++;
 431         return (cache_victim());        /* new credential */
 432 }
 433
 434
 435 #if (defined(sun) || defined(vax) || defined(__FreeBSD__))
 436 /*
 437  * Local credential handling stuff.
 438  * NOTE: bsd unix dependent.
 439  * Other operating systems should put something else here.
 440  */
 441 #define UNKNOWN         -2      /* grouplen, if cached cred is unknown user */
 442 #define INVALID         -1      /* grouplen, if cache entry is invalid */
 443
 444 struct bsdcred {
 445         short uid;              /* cached uid */
 446         short gid;              /* cached gid */
 447         short grouplen; /* length of cached groups */
 448         short groups[NGROUPS];  /* cached groups */
 449 };
 450
 451 /*
 452  * Map a des credential into a unix cred.
 453  * We cache the credential here so the application does
 454  * not have to make an rpc call every time to interpret
 455  * the credential.
 456  */
 457 int
 458 authdes_getucred(adc, uid, gid, grouplen, groups)
 459         struct authdes_cred *adc;
 460         uid_t *uid;
 461         gid_t *gid;
 462         int *grouplen;
 463         register gid_t *groups;
 464 {
 465         unsigned sid;
 466         register int i;
 467         uid_t i_uid;
 468         gid_t i_gid;
 469         int i_grouplen;
 470         struct bsdcred *cred;
 471
 472         sid = adc->adc_nickname;
 473         if (sid >= AUTHDES_CACHESZ) {
 474                 debug("invalid nickname");
 475                 return (0);
 476         }
 477         cred = (struct bsdcred *)authdes_cache[sid].localcred;
 478         if (cred == NULL) {
 479                 cred = (struct bsdcred *)mem_alloc(sizeof(struct bsdcred));
 480                 authdes_cache[sid].localcred = (char *)cred;
 481                 cred->grouplen = INVALID;
 482         }
 483         if (cred->grouplen == INVALID) {
 484                 /*
 485                  * not in cache: lookup
 486                  */
 487                 if (!netname2user(adc->adc_fullname.name, &i_uid, &i_gid,
 488                         &i_grouplen, groups))
 489                 {
 490                         debug("unknown netname");
 491                         cred->grouplen = UNKNOWN;       /* mark as lookup up, but not found */
 492                         return (0);
 493                 }
 494                 debug("missed ucred cache");
 495                 *uid = cred->uid = i_uid;
 496                 *gid = cred->gid = i_gid;
 497                 *grouplen = cred->grouplen = i_grouplen;
 498                 for (i = i_grouplen - 1; i >= 0; i--) {
 499                         cred->groups[i] = groups[i]; /* int to short */
 500                 }
 501                 return (1);
 502         } else if (cred->grouplen == UNKNOWN) {
 503                 /*
 504                  * Already lookup up, but no match found
 505                  */
 506                 return (0);
 507         }
 508
 509         /*
 510          * cached credentials
 511          */
 512         *uid = cred->uid;
 513         *gid = cred->gid;
 514         *grouplen = cred->grouplen;
 515         for (i = cred->grouplen - 1; i >= 0; i--) {
 516                 groups[i] = cred->groups[i];    /* short to int */
 517         }
 518         return (1);
 519 }
 520
 521 static void
 522 invalidate(cred)
 523         char *cred;
 524 {
 525         if (cred == NULL) {
 526                 return;
 527         }
 528         ((struct bsdcred *)cred)->grouplen = INVALID;
 529 }
 530 #endif
 531