granicus.if.org Git - postgresql/blob - src/interfaces/libpq/fe-auth.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * fe-auth.c
   4  *         The front-end (client) authorization routines
   5  *
   6  * Copyright (c) 1994, Regents of the University of California
   7  *
   8  * NOTE: the error message strings returned by this module must not
   9  * exceed INITIAL_EXPBUFFER_SIZE (currently 256 bytes).
  10  *
  11  * IDENTIFICATION
  12  *        $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-auth.c,v 1.35 2000/01/18 19:05:31 momjian Exp $
  13  *
  14  *-------------------------------------------------------------------------
  15  */
  16
  17 /*
  18  * INTERFACE ROUTINES
  19  *         frontend (client) routines:
  20  *              fe_sendauth                             send authentication information
  21  *              fe_getauthname                  get user's name according to the client side
  22  *                                                              of the authentication system
  23  *              fe_setauthsvc                   set frontend authentication service
  24  *              fe_getauthsvc                   get current frontend authentication service
  25  *
  26  *
  27  *
  28  */
  29
  30 #ifndef WIN32
  31 #include "postgres.h"
  32 #endif
  33 #include "libpq-fe.h"
  34 #include "libpq-int.h"
  35 #include "fe-auth.h"
  36
  37 #ifdef WIN32
  38 #include "win32.h"
  39 #else
  40 #include <unistd.h>
  41 #include <sys/param.h>                  /* for MAXHOSTNAMELEN on most */
  42 #ifndef  MAXHOSTNAMELEN
  43 #include <netdb.h>                              /* for MAXHOSTNAMELEN on some */
  44 #endif
  45 #include <pwd.h>
  46 #endif
  47
  48 #ifdef HAVE_CRYPT_H
  49 #include <crypt.h>
  50 #endif
  51
  52
  53 /*----------------------------------------------------------------
  54  * common definitions for generic fe/be routines
  55  *----------------------------------------------------------------
  56  */
  57
  58 struct authsvc
  59 {
  60         char            name[NAMEDATALEN];              /* service nickname (for command
  61                                                                                  * line) */
  62         MsgType         msgtype;                /* startup packet header type */
  63         int                     allowed;                /* initially allowed (before command line
  64                                                                  * option parsing)? */
  65 };
  66
  67 /*
  68  * Command-line parsing routines use this structure to map nicknames
  69  * onto service types (and the startup packets to use with them).
  70  *
  71  * Programs receiving an authentication request use this structure to
  72  * decide which authentication service types are currently permitted.
  73  * By default, all authentication systems compiled into the system are
  74  * allowed.  Unauthenticated connections are disallowed unless there
  75  * isn't any authentication system.
  76  */
  77 static struct authsvc authsvcs[] = {
  78 #ifdef KRB4
  79         {"krb4", STARTUP_KRB4_MSG, 1},
  80         {"kerberos", STARTUP_KRB4_MSG, 1},
  81 #endif   /* KRB4 */
  82 #ifdef KRB5
  83         {"krb5", STARTUP_KRB5_MSG, 1},
  84         {"kerberos", STARTUP_KRB5_MSG, 1},
  85 #endif   /* KRB5 */
  86         {UNAUTHNAME, STARTUP_MSG,
  87 #if defined(KRB4) || defined(KRB5)
  88                 0
  89 #else                                                   /* !(KRB4 || KRB5) */
  90                 1
  91 #endif   /* !(KRB4 || KRB5) */
  92         },
  93         {"password", STARTUP_PASSWORD_MSG, 0}
  94 };
  95
  96 static int      n_authsvcs = sizeof(authsvcs) / sizeof(struct authsvc);
  97
  98 #ifdef KRB4
  99 /*----------------------------------------------------------------
 100  * MIT Kerberos authentication system - protocol version 4
 101  *----------------------------------------------------------------
 102  */
 103
 104 #include "krb.h"
 105
 106 /* for some reason, this is not defined in krb.h ... */
 107 extern char *tkt_string(void);
 108
 109 /*
 110  * pg_krb4_init -- initialization performed before any Kerberos calls are made
 111  *
 112  * For v4, all we need to do is make sure the library routines get the right
 113  * ticket file if we want them to see a special one.  (They will open the file
 114  * themselves.)
 115  */
 116 static void
 117 pg_krb4_init()
 118 {
 119         char       *realm;
 120         static          init_done = 0;
 121
 122         if (init_done)
 123                 return;
 124         init_done = 1;
 125
 126         /*
 127          * If the user set PGREALM, then we use a ticket file with a special
 128          * name: <usual-ticket-file-name>@<PGREALM-value>
 129          */
 130         if (realm = getenv("PGREALM"))
 131         {
 132                 char            tktbuf[MAXPGPATH];
 133
 134                 (void) sprintf(tktbuf, "%s@%s", tkt_string(), realm);
 135                 krb_set_tkt_string(tktbuf);
 136         }
 137 }
 138
 139 /*
 140  * pg_krb4_authname -- returns a pointer to static space containing whatever
 141  *                                         name the user has authenticated to the system
 142  *
 143  * We obtain this information by digging around in the ticket file.
 144  */
 145 static char *
 146 pg_krb4_authname(char *PQerrormsg)
 147 {
 148         char            instance[INST_SZ + 1];
 149         char            realm[REALM_SZ + 1];
 150         int                     status;
 151         static char name[SNAME_SZ + 1] = "";
 152
 153         if (name[0])
 154                 return name;
 155
 156         pg_krb4_init();
 157
 158         name[SNAME_SZ] = '\0';
 159         status = krb_get_tf_fullname(tkt_string(), name, instance, realm);
 160         if (status != KSUCCESS)
 161         {
 162                 (void) sprintf(PQerrormsg,
 163                                            "pg_krb4_authname: krb_get_tf_fullname: %s\n",
 164                                            krb_err_txt[status]);
 165                 return (char *) NULL;
 166         }
 167         return name;
 168 }
 169
 170 /*
 171  * pg_krb4_sendauth -- client routine to send authentication information to
 172  *                                         the server
 173  *
 174  * This routine does not do mutual authentication, nor does it return enough
 175  * information to do encrypted connections.  But then, if we want to do
 176  * encrypted connections, we'll have to redesign the whole RPC mechanism
 177  * anyway.
 178  *
 179  * If the user is too lazy to feed us a hostname, we try to come up with
 180  * something other than "localhost" since the hostname is used as an
 181  * instance and instance names in v4 databases are usually actual hostnames
 182  * (canonicalized to omit all domain suffixes).
 183  */
 184 static int
 185 pg_krb4_sendauth(const char *PQerrormsg, int sock,
 186                                  struct sockaddr_in * laddr,
 187                                  struct sockaddr_in * raddr,
 188                                  const char *hostname)
 189 {
 190         long            krbopts = 0;    /* one-way authentication */
 191         KTEXT_ST        clttkt;
 192         int                     status;
 193         char            hostbuf[MAXHOSTNAMELEN];
 194         const char *realm = getenv("PGREALM");          /* NULL == current realm */
 195
 196         if (!hostname || !(*hostname))
 197         {
 198                 if (gethostname(hostbuf, MAXHOSTNAMELEN) < 0)
 199                         strcpy(hostbuf, "localhost");
 200                 hostname = hostbuf;
 201         }
 202
 203         pg_krb4_init();
 204
 205         status = krb_sendauth(krbopts,
 206                                                   sock,
 207                                                   &clttkt,
 208                                                   PG_KRB_SRVNAM,
 209                                                   hostname,
 210                                                   realm,
 211                                                   (u_long) 0,
 212                                                   (MSG_DAT *) NULL,
 213                                                   (CREDENTIALS *) NULL,
 214                                                   (Key_schedule *) NULL,
 215                                                   laddr,
 216                                                   raddr,
 217                                                   PG_KRB4_VERSION);
 218         if (status != KSUCCESS)
 219         {
 220                 (void) sprintf(PQerrormsg,
 221                                            "pg_krb4_sendauth: kerberos error: %s\n",
 222                                            krb_err_txt[status]);
 223                 return STATUS_ERROR;
 224         }
 225         return STATUS_OK;
 226 }
 227
 228 #endif   /* KRB4 */
 229
 230 #ifdef KRB5
 231 /*----------------------------------------------------------------
 232  * MIT Kerberos authentication system - protocol version 5
 233  *----------------------------------------------------------------
 234  */
 235
 236 #include "krb5/krb5.h"
 237
 238 /*
 239  * pg_an_to_ln -- return the local name corresponding to an authentication
 240  *                                name
 241  *
 242  * XXX Assumes that the first aname component is the user name.  This is NOT
 243  *         necessarily so, since an aname can actually be something out of your
 244  *         worst X.400 nightmare, like
 245  *                ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
 246  *         Note that the MIT an_to_ln code does the same thing if you don't
 247  *         provide an aname mapping database...it may be a better idea to use
 248  *         krb5_an_to_ln, except that it punts if multiple components are found,
 249  *         and we can't afford to punt.
 250  */
 251 static char *
 252 pg_an_to_ln(const char *aname)
 253 {
 254         char       *p;
 255
 256         if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
 257                 *p = '\0';
 258         return aname;
 259 }
 260
 261
 262 /*
 263  * pg_krb5_init -- initialization performed before any Kerberos calls are made
 264  *
 265  * With v5, we can no longer set the ticket (credential cache) file name;
 266  * we now have to provide a file handle for the open (well, "resolved")
 267  * ticket file everywhere.
 268  *
 269  */
 270 static int
 271                         krb5_ccache
 272 pg_krb5_init(void)
 273 {
 274         krb5_error_code code;
 275         char       *realm,
 276                            *defname;
 277         char            tktbuf[MAXPGPATH];
 278         static krb5_ccache ccache = (krb5_ccache) NULL;
 279
 280         if (ccache)
 281                 return ccache;
 282
 283         /*
 284          * If the user set PGREALM, then we use a ticket file with a special
 285          * name: <usual-ticket-file-name>@<PGREALM-value>
 286          */
 287         if (!(defname = krb5_cc_default_name()))
 288         {
 289                 (void) sprintf(PQerrormsg,
 290                                            "pg_krb5_init: krb5_cc_default_name failed\n");
 291                 return (krb5_ccache) NULL;
 292         }
 293         strcpy(tktbuf, defname);
 294         if (realm = getenv("PGREALM"))
 295         {
 296                 strcat(tktbuf, "@");
 297                 strcat(tktbuf, realm);
 298         }
 299
 300         if (code = krb5_cc_resolve(tktbuf, &ccache))
 301         {
 302                 (void) sprintf(PQerrormsg,
 303                    "pg_krb5_init: Kerberos error %d in krb5_cc_resolve\n", code);
 304                 com_err("pg_krb5_init", code, "in krb5_cc_resolve");
 305                 return (krb5_ccache) NULL;
 306         }
 307         return ccache;
 308 }
 309
 310 /*
 311  * pg_krb5_authname -- returns a pointer to static space containing whatever
 312  *                                         name the user has authenticated to the system
 313  *
 314  * We obtain this information by digging around in the ticket file.
 315  */
 316 static const char *
 317 pg_krb5_authname(const char *PQerrormsg)
 318 {
 319         krb5_ccache ccache;
 320         krb5_principal principal;
 321         krb5_error_code code;
 322         static char *authname = (char *) NULL;
 323
 324         if (authname)
 325                 return authname;
 326
 327         ccache = pg_krb5_init();        /* don't free this */
 328
 329         if (code = krb5_cc_get_principal(ccache, &principal))
 330         {
 331                 (void) sprintf(PQerrormsg,
 332                                            "pg_krb5_authname: Kerberos error %d in krb5_cc_get_principal\n", code);
 333                 com_err("pg_krb5_authname", code, "in krb5_cc_get_principal");
 334                 return (char *) NULL;
 335         }
 336         if (code = krb5_unparse_name(principal, &authname))
 337         {
 338                 (void) sprintf(PQerrormsg,
 339                                            "pg_krb5_authname: Kerberos error %d in krb5_unparse_name\n", code);
 340                 com_err("pg_krb5_authname", code, "in krb5_unparse_name");
 341                 krb5_free_principal(principal);
 342                 return (char *) NULL;
 343         }
 344         krb5_free_principal(principal);
 345         return pg_an_to_ln(authname);
 346 }
 347
 348 /*
 349  * pg_krb5_sendauth -- client routine to send authentication information to
 350  *                                         the server
 351  *
 352  * This routine does not do mutual authentication, nor does it return enough
 353  * information to do encrypted connections.  But then, if we want to do
 354  * encrypted connections, we'll have to redesign the whole RPC mechanism
 355  * anyway.
 356  *
 357  * Server hostnames are canonicalized v4-style, i.e., all domain suffixes
 358  * are simply chopped off.      Hence, we are assuming that you've entered your
 359  * server instances as
 360  *              <value-of-PG_KRB_SRVNAM>/<canonicalized-hostname>
 361  * in the PGREALM (or local) database.  This is probably a bad assumption.
 362  */
 363 static int
 364 pg_krb5_sendauth(const char *PQerrormsg, int sock,
 365                                  struct sockaddr_in * laddr,
 366                                  struct sockaddr_in * raddr,
 367                                  const char *hostname)
 368 {
 369         char            servbuf[MAXHOSTNAMELEN + 1 +
 370                                                                         sizeof(PG_KRB_SRVNAM)];
 371         const char *hostp;
 372         const char *realm;
 373         krb5_error_code code;
 374         krb5_principal client,
 375                                 server;
 376         krb5_ccache ccache;
 377         krb5_error *error = (krb5_error *) NULL;
 378
 379         ccache = pg_krb5_init();        /* don't free this */
 380
 381         /*
 382          * set up client -- this is easy, we can get it out of the ticket
 383          * file.
 384          */
 385         if (code = krb5_cc_get_principal(ccache, &client))
 386         {
 387                 (void) sprintf(PQerrormsg,
 388                                            "pg_krb5_sendauth: Kerberos error %d in krb5_cc_get_principal\n", code);
 389                 com_err("pg_krb5_sendauth", code, "in krb5_cc_get_principal");
 390                 return STATUS_ERROR;
 391         }
 392
 393         /*
 394          * set up server -- canonicalize as described above
 395          */
 396         strcpy(servbuf, PG_KRB_SRVNAM);
 397         *(hostp = servbuf + (sizeof(PG_KRB_SRVNAM) - 1)) = '/';
 398         if (hostname || *hostname)
 399                 strncpy(++hostp, hostname, MAXHOSTNAMELEN);
 400         else
 401         {
 402                 if (gethostname(++hostp, MAXHOSTNAMELEN) < 0)
 403                         strcpy(hostp, "localhost");
 404         }
 405         if (hostp = strchr(hostp, '.'))
 406                 *hostp = '\0';
 407         if (realm = getenv("PGREALM"))
 408         {
 409                 strcat(servbuf, "@");
 410                 strcat(servbuf, realm);
 411         }
 412         if (code = krb5_parse_name(servbuf, &server))
 413         {
 414                 (void) sprintf(PQerrormsg,
 415                 "pg_krb5_sendauth: Kerberos error %d in krb5_parse_name\n", code);
 416                 com_err("pg_krb5_sendauth", code, "in krb5_parse_name");
 417                 krb5_free_principal(client);
 418                 return STATUS_ERROR;
 419         }
 420
 421         /*
 422          * The only thing we want back from krb5_sendauth is an error status
 423          * and any error messages.
 424          */
 425         if (code = krb5_sendauth((krb5_pointer) & sock,
 426                                                          PG_KRB5_VERSION,
 427                                                          client,
 428                                                          server,
 429                                                          (krb5_flags) 0,
 430                                                          (krb5_checksum *) NULL,
 431                                                          (krb5_creds *) NULL,
 432                                                          ccache,
 433                                                          (krb5_int32 *) NULL,
 434                                                          (krb5_keyblock **) NULL,
 435                                                          &error,
 436                                                          (krb5_ap_rep_enc_part **) NULL))
 437         {
 438                 if ((code == KRB5_SENDAUTH_REJECTED) && error)
 439                 {
 440                         (void) sprintf(PQerrormsg,
 441                                   "pg_krb5_sendauth: authentication rejected: \"%*s\"\n",
 442                                                    error->text.length, error->text.data);
 443                 }
 444                 else
 445                 {
 446                         (void) sprintf(PQerrormsg,
 447                                                    "pg_krb5_sendauth: Kerberos error %d in krb5_sendauth\n", code);
 448                         com_err("pg_krb5_sendauth", code, "in krb5_sendauth");
 449                 }
 450         }
 451         krb5_free_principal(client);
 452         krb5_free_principal(server);
 453         return code ? STATUS_ERROR : STATUS_OK;
 454 }
 455
 456 #endif   /* KRB5 */
 457
 458 static int
 459 pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
 460 {
 461         /* Encrypt the password if needed. */
 462
 463         if (areq == AUTH_REQ_CRYPT)
 464                 password = crypt(password, conn->salt);
 465
 466         return pqPacketSend(conn, password, strlen(password) + 1);
 467 }
 468
 469 /*
 470  * fe_sendauth -- client demux routine for outgoing authentication information
 471  */
 472 int
 473 fe_sendauth(AuthRequest areq, PGconn *conn, const char *hostname,
 474                         const char *password, char *PQerrormsg)
 475 {
 476         switch (areq)
 477         {
 478                         case AUTH_REQ_OK:
 479                         break;
 480
 481                 case AUTH_REQ_KRB4:
 482 #ifdef KRB4
 483                         if (pg_krb4_sendauth(PQerrormsg, conn->sock, &conn->laddr.in,
 484                                                                  &conn->raddr.in,
 485                                                                  hostname) != STATUS_OK)
 486                         {
 487                                 (void) sprintf(PQerrormsg,
 488                                                         "fe_sendauth: krb4 authentication failed\n");
 489                                 return STATUS_ERROR;
 490                         }
 491                         break;
 492 #else
 493                         (void) sprintf(PQerrormsg,
 494                                          "fe_sendauth: krb4 authentication not supported\n");
 495                         return STATUS_ERROR;
 496 #endif
 497
 498                 case AUTH_REQ_KRB5:
 499 #ifdef KRB5
 500                         if (pg_krb5_sendauth(PQerrormsg, conn->sock, &conn->laddr.in,
 501                                                                  &conn->raddr.in,
 502                                                                  hostname) != STATUS_OK)
 503                         {
 504                                 (void) sprintf(PQerrormsg,
 505                                                         "fe_sendauth: krb5 authentication failed\n");
 506                                 return STATUS_ERROR;
 507                         }
 508                         break;
 509 #else
 510                         (void) sprintf(PQerrormsg,
 511                                          "fe_sendauth: krb5 authentication not supported\n");
 512                         return STATUS_ERROR;
 513 #endif
 514
 515                 case AUTH_REQ_PASSWORD:
 516                 case AUTH_REQ_CRYPT:
 517                         if (password == NULL || *password == '\0')
 518                         {
 519                                 (void) sprintf(PQerrormsg,
 520                                                            "fe_sendauth: no password supplied\n");
 521                                 return STATUS_ERROR;
 522                         }
 523                         if (pg_password_sendauth(conn, password, areq) != STATUS_OK)
 524                         {
 525                                 (void) sprintf(PQerrormsg,
 526                                  "fe_sendauth: error sending password authentication\n");
 527                                 return STATUS_ERROR;
 528                         }
 529
 530                         break;
 531
 532                 default:
 533                         (void) sprintf(PQerrormsg,
 534                         "fe_sendauth: authentication type %u not supported\n", areq);
 535                         return STATUS_ERROR;
 536         }
 537
 538         return STATUS_OK;
 539 }
 540
 541 /*
 542  * fe_setauthsvc
 543  * fe_getauthsvc
 544  *
 545  * Set/return the authentication service currently selected for use by the
 546  * frontend. (You can only use one in the frontend, obviously.)
 547  */
 548 static int      pg_authsvc = -1;
 549
 550 void
 551 fe_setauthsvc(const char *name, char *PQerrormsg)
 552 {
 553         int                     i;
 554
 555         for (i = 0; i < n_authsvcs; ++i)
 556                 if (!strcmp(name, authsvcs[i].name))
 557                 {
 558                         pg_authsvc = i;
 559                         break;
 560                 }
 561         if (i == n_authsvcs)
 562         {
 563                 (void) sprintf(PQerrormsg,
 564                                            "fe_setauthsvc: invalid name: %s, ignoring...\n",
 565                                            name);
 566         }
 567         return;
 568 }
 569
 570 MsgType
 571 fe_getauthsvc(char *PQerrormsg)
 572 {
 573         if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
 574                 fe_setauthsvc(DEFAULT_CLIENT_AUTHSVC, PQerrormsg);
 575         return authsvcs[pg_authsvc].msgtype;
 576 }
 577
 578 /*
 579  * fe_getauthname -- returns a pointer to dynamic space containing whatever
 580  *                                       name the user has authenticated to the system
 581  * if there is an error, return the error message in PQerrormsg
 582  */
 583 char *
 584 fe_getauthname(char *PQerrormsg)
 585 {
 586         char       *name = (char *) NULL;
 587         char       *authn = (char *) NULL;
 588         MsgType         authsvc;
 589
 590         authsvc = fe_getauthsvc(PQerrormsg);
 591         switch ((int) authsvc)
 592         {
 593 #ifdef KRB4
 594                 case STARTUP_KRB4_MSG:
 595                         name = pg_krb4_authname(PQerrormsg);
 596                         break;
 597 #endif
 598 #ifdef KRB5
 599                 case STARTUP_KRB5_MSG:
 600                         name = pg_krb5_authname(PQerrormsg);
 601                         break;
 602 #endif
 603                 case STARTUP_MSG:
 604                         {
 605 #ifdef WIN32
 606                                 char            username[128];
 607                                 DWORD           namesize = sizeof(username) - 1;
 608
 609                                 if (GetUserName(username, &namesize))
 610                                         name = username;
 611 #else
 612                                 struct passwd *pw = getpwuid(geteuid());
 613
 614                                 if (pw)
 615                                         name = pw->pw_name;
 616 #endif
 617                         }
 618                         break;
 619                 default:
 620                         (void) sprintf(PQerrormsg,
 621                                    "fe_getauthname: invalid authentication system: %d\n",
 622                                                    authsvc);
 623                         break;
 624         }
 625
 626         if (name && (authn = (char *) malloc(strlen(name) + 1)))
 627                 strcpy(authn, name);
 628         return authn;
 629 }