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 1.33 1999/08/31 01:37:36 tgl 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 #include "postgres.h"
  31 #include "libpq-fe.h"
  32 #include "libpq-int.h"
  33 #include "fe-auth.h"
  34
  35 #ifdef WIN32
  36 #include "win32.h"
  37 #else
  38 #include <unistd.h>
  39 #include <sys/param.h>                  /* for MAXHOSTNAMELEN on most */
  40 #ifndef  MAXHOSTNAMELEN
  41 #include <netdb.h>                              /* for MAXHOSTNAMELEN on some */
  42 #endif
  43 #include <pwd.h>
  44 #endif
  45
  46 #ifdef HAVE_CRYPT_H
  47 #include <crypt.h>
  48 #endif
  49
  50
  51 /*----------------------------------------------------------------
  52  * common definitions for generic fe/be routines
  53  *----------------------------------------------------------------
  54  */
  55
  56 struct authsvc
  57 {
  58         char            name[NAMEDATALEN];              /* service nickname (for command
  59                                                                                  * line) */
  60         MsgType         msgtype;                /* startup packet header type */
  61         int                     allowed;                /* initially allowed (before command line
  62                                                                  * option parsing)? */
  63 };
  64
  65 /*
  66  * Command-line parsing routines use this structure to map nicknames
  67  * onto service types (and the startup packets to use with them).
  68  *
  69  * Programs receiving an authentication request use this structure to
  70  * decide which authentication service types are currently permitted.
  71  * By default, all authentication systems compiled into the system are
  72  * allowed.  Unauthenticated connections are disallowed unless there
  73  * isn't any authentication system.
  74  */
  75 static struct authsvc authsvcs[] = {
  76 #ifdef KRB4
  77         {"krb4", STARTUP_KRB4_MSG, 1},
  78         {"kerberos", STARTUP_KRB4_MSG, 1},
  79 #endif   /* KRB4 */
  80 #ifdef KRB5
  81         {"krb5", STARTUP_KRB5_MSG, 1},
  82         {"kerberos", STARTUP_KRB5_MSG, 1},
  83 #endif   /* KRB5 */
  84         {UNAUTHNAME, STARTUP_MSG,
  85 #if defined(KRB4) || defined(KRB5)
  86                 0
  87 #else                                                   /* !(KRB4 || KRB5) */
  88                 1
  89 #endif   /* !(KRB4 || KRB5) */
  90         },
  91         {"password", STARTUP_PASSWORD_MSG, 0}
  92 };
  93
  94 static int      n_authsvcs = sizeof(authsvcs) / sizeof(struct authsvc);
  95
  96 #ifdef KRB4
  97 /*----------------------------------------------------------------
  98  * MIT Kerberos authentication system - protocol version 4
  99  *----------------------------------------------------------------
 100  */
 101
 102 #include "krb.h"
 103
 104 /* for some reason, this is not defined in krb.h ... */
 105 extern char *tkt_string(void);
 106
 107 /*
 108  * pg_krb4_init -- initialization performed before any Kerberos calls are made
 109  *
 110  * For v4, all we need to do is make sure the library routines get the right
 111  * ticket file if we want them to see a special one.  (They will open the file
 112  * themselves.)
 113  */
 114 static void
 115 pg_krb4_init()
 116 {
 117         char       *realm;
 118         static          init_done = 0;
 119
 120         if (init_done)
 121                 return;
 122         init_done = 1;
 123
 124         /*
 125          * If the user set PGREALM, then we use a ticket file with a special
 126          * name: <usual-ticket-file-name>@<PGREALM-value>
 127          */
 128         if (realm = getenv("PGREALM"))
 129         {
 130                 char            tktbuf[MAXPATHLEN];
 131
 132                 (void) sprintf(tktbuf, "%s@%s", tkt_string(), realm);
 133                 krb_set_tkt_string(tktbuf);
 134         }
 135 }
 136
 137 /*
 138  * pg_krb4_authname -- returns a pointer to static space containing whatever
 139  *                                         name the user has authenticated to the system
 140  *
 141  * We obtain this information by digging around in the ticket file.
 142  */
 143 static char *
 144 pg_krb4_authname(char *PQerrormsg)
 145 {
 146         char            instance[INST_SZ + 1];
 147         char            realm[REALM_SZ + 1];
 148         int                     status;
 149         static char name[SNAME_SZ + 1] = "";
 150
 151         if (name[0])
 152                 return name;
 153
 154         pg_krb4_init();
 155
 156         name[SNAME_SZ] = '\0';
 157         status = krb_get_tf_fullname(tkt_string(), name, instance, realm);
 158         if (status != KSUCCESS)
 159         {
 160                 (void) sprintf(PQerrormsg,
 161                                            "pg_krb4_authname: krb_get_tf_fullname: %s\n",
 162                                            krb_err_txt[status]);
 163                 return (char *) NULL;
 164         }
 165         return name;
 166 }
 167
 168 /*
 169  * pg_krb4_sendauth -- client routine to send authentication information to
 170  *                                         the server
 171  *
 172  * This routine does not do mutual authentication, nor does it return enough
 173  * information to do encrypted connections.  But then, if we want to do
 174  * encrypted connections, we'll have to redesign the whole RPC mechanism
 175  * anyway.
 176  *
 177  * If the user is too lazy to feed us a hostname, we try to come up with
 178  * something other than "localhost" since the hostname is used as an
 179  * instance and instance names in v4 databases are usually actual hostnames
 180  * (canonicalized to omit all domain suffixes).
 181  */
 182 static int
 183 pg_krb4_sendauth(const char *PQerrormsg, int sock,
 184                                  struct sockaddr_in * laddr,
 185                                  struct sockaddr_in * raddr,
 186                                  const char *hostname)
 187 {
 188         long            krbopts = 0;    /* one-way authentication */
 189         KTEXT_ST        clttkt;
 190         int                     status;
 191         char            hostbuf[MAXHOSTNAMELEN];
 192         const char *realm = getenv("PGREALM");          /* NULL == current realm */
 193
 194         if (!hostname || !(*hostname))
 195         {
 196                 if (gethostname(hostbuf, MAXHOSTNAMELEN) < 0)
 197                         strcpy(hostbuf, "localhost");
 198                 hostname = hostbuf;
 199         }
 200
 201         pg_krb4_init();
 202
 203         status = krb_sendauth(krbopts,
 204                                                   sock,
 205                                                   &clttkt,
 206                                                   PG_KRB_SRVNAM,
 207                                                   hostname,
 208                                                   realm,
 209                                                   (u_long) 0,
 210                                                   (MSG_DAT *) NULL,
 211                                                   (CREDENTIALS *) NULL,
 212                                                   (Key_schedule *) NULL,
 213                                                   laddr,
 214                                                   raddr,
 215                                                   PG_KRB4_VERSION);
 216         if (status != KSUCCESS)
 217         {
 218                 (void) sprintf(PQerrormsg,
 219                                            "pg_krb4_sendauth: kerberos error: %s\n",
 220                                            krb_err_txt[status]);
 221                 return STATUS_ERROR;
 222         }
 223         return STATUS_OK;
 224 }
 225
 226 #endif   /* KRB4 */
 227
 228 #ifdef KRB5
 229 /*----------------------------------------------------------------
 230  * MIT Kerberos authentication system - protocol version 5
 231  *----------------------------------------------------------------
 232  */
 233
 234 #include "krb5/krb5.h"
 235
 236 /*
 237  * pg_an_to_ln -- return the local name corresponding to an authentication
 238  *                                name
 239  *
 240  * XXX Assumes that the first aname component is the user name.  This is NOT
 241  *         necessarily so, since an aname can actually be something out of your
 242  *         worst X.400 nightmare, like
 243  *                ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
 244  *         Note that the MIT an_to_ln code does the same thing if you don't
 245  *         provide an aname mapping database...it may be a better idea to use
 246  *         krb5_an_to_ln, except that it punts if multiple components are found,
 247  *         and we can't afford to punt.
 248  */
 249 static char *
 250 pg_an_to_ln(const char *aname)
 251 {
 252         char       *p;
 253
 254         if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
 255                 *p = '\0';
 256         return aname;
 257 }
 258
 259
 260 /*
 261  * pg_krb5_init -- initialization performed before any Kerberos calls are made
 262  *
 263  * With v5, we can no longer set the ticket (credential cache) file name;
 264  * we now have to provide a file handle for the open (well, "resolved")
 265  * ticket file everywhere.
 266  *
 267  */
 268 static int
 269                         krb5_ccache
 270 pg_krb5_init(void)
 271 {
 272         krb5_error_code code;
 273         char       *realm,
 274                            *defname;
 275         char            tktbuf[MAXPATHLEN];
 276         static krb5_ccache ccache = (krb5_ccache) NULL;
 277
 278         if (ccache)
 279                 return ccache;
 280
 281         /*
 282          * If the user set PGREALM, then we use a ticket file with a special
 283          * name: <usual-ticket-file-name>@<PGREALM-value>
 284          */
 285         if (!(defname = krb5_cc_default_name()))
 286         {
 287                 (void) sprintf(PQerrormsg,
 288                                            "pg_krb5_init: krb5_cc_default_name failed\n");
 289                 return (krb5_ccache) NULL;
 290         }
 291         strcpy(tktbuf, defname);
 292         if (realm = getenv("PGREALM"))
 293         {
 294                 strcat(tktbuf, "@");
 295                 strcat(tktbuf, realm);
 296         }
 297
 298         if (code = krb5_cc_resolve(tktbuf, &ccache))
 299         {
 300                 (void) sprintf(PQerrormsg,
 301                    "pg_krb5_init: Kerberos error %d in krb5_cc_resolve\n", code);
 302                 com_err("pg_krb5_init", code, "in krb5_cc_resolve");
 303                 return (krb5_ccache) NULL;
 304         }
 305         return ccache;
 306 }
 307
 308 /*
 309  * pg_krb5_authname -- returns a pointer to static space containing whatever
 310  *                                         name the user has authenticated to the system
 311  *
 312  * We obtain this information by digging around in the ticket file.
 313  */
 314 static const char *
 315 pg_krb5_authname(const char *PQerrormsg)
 316 {
 317         krb5_ccache ccache;
 318         krb5_principal principal;
 319         krb5_error_code code;
 320         static char *authname = (char *) NULL;
 321
 322         if (authname)
 323                 return authname;
 324
 325         ccache = pg_krb5_init();        /* don't free this */
 326
 327         if (code = krb5_cc_get_principal(ccache, &principal))
 328         {
 329                 (void) sprintf(PQerrormsg,
 330                                            "pg_krb5_authname: Kerberos error %d in krb5_cc_get_principal\n", code);
 331                 com_err("pg_krb5_authname", code, "in krb5_cc_get_principal");
 332                 return (char *) NULL;
 333         }
 334         if (code = krb5_unparse_name(principal, &authname))
 335         {
 336                 (void) sprintf(PQerrormsg,
 337                                            "pg_krb5_authname: Kerberos error %d in krb5_unparse_name\n", code);
 338                 com_err("pg_krb5_authname", code, "in krb5_unparse_name");
 339                 krb5_free_principal(principal);
 340                 return (char *) NULL;
 341         }
 342         krb5_free_principal(principal);
 343         return pg_an_to_ln(authname);
 344 }
 345
 346 /*
 347  * pg_krb5_sendauth -- client routine to send authentication information to
 348  *                                         the server
 349  *
 350  * This routine does not do mutual authentication, nor does it return enough
 351  * information to do encrypted connections.  But then, if we want to do
 352  * encrypted connections, we'll have to redesign the whole RPC mechanism
 353  * anyway.
 354  *
 355  * Server hostnames are canonicalized v4-style, i.e., all domain suffixes
 356  * are simply chopped off.      Hence, we are assuming that you've entered your
 357  * server instances as
 358  *              <value-of-PG_KRB_SRVNAM>/<canonicalized-hostname>
 359  * in the PGREALM (or local) database.  This is probably a bad assumption.
 360  */
 361 static int
 362 pg_krb5_sendauth(const char *PQerrormsg, int sock,
 363                                  struct sockaddr_in * laddr,
 364                                  struct sockaddr_in * raddr,
 365                                  const char *hostname)
 366 {
 367         char            servbuf[MAXHOSTNAMELEN + 1 +
 368                                                                         sizeof(PG_KRB_SRVNAM)];
 369         const char *hostp;
 370         const char *realm;
 371         krb5_error_code code;
 372         krb5_principal client,
 373                                 server;
 374         krb5_ccache ccache;
 375         krb5_error *error = (krb5_error *) NULL;
 376
 377         ccache = pg_krb5_init();        /* don't free this */
 378
 379         /*
 380          * set up client -- this is easy, we can get it out of the ticket
 381          * file.
 382          */
 383         if (code = krb5_cc_get_principal(ccache, &client))
 384         {
 385                 (void) sprintf(PQerrormsg,
 386                                            "pg_krb5_sendauth: Kerberos error %d in krb5_cc_get_principal\n", code);
 387                 com_err("pg_krb5_sendauth", code, "in krb5_cc_get_principal");
 388                 return STATUS_ERROR;
 389         }
 390
 391         /*
 392          * set up server -- canonicalize as described above
 393          */
 394         strcpy(servbuf, PG_KRB_SRVNAM);
 395         *(hostp = servbuf + (sizeof(PG_KRB_SRVNAM) - 1)) = '/';
 396         if (hostname || *hostname)
 397                 strncpy(++hostp, hostname, MAXHOSTNAMELEN);
 398         else
 399         {
 400                 if (gethostname(++hostp, MAXHOSTNAMELEN) < 0)
 401                         strcpy(hostp, "localhost");
 402         }
 403         if (hostp = strchr(hostp, '.'))
 404                 *hostp = '\0';
 405         if (realm = getenv("PGREALM"))
 406         {
 407                 strcat(servbuf, "@");
 408                 strcat(servbuf, realm);
 409         }
 410         if (code = krb5_parse_name(servbuf, &server))
 411         {
 412                 (void) sprintf(PQerrormsg,
 413                 "pg_krb5_sendauth: Kerberos error %d in krb5_parse_name\n", code);
 414                 com_err("pg_krb5_sendauth", code, "in krb5_parse_name");
 415                 krb5_free_principal(client);
 416                 return STATUS_ERROR;
 417         }
 418
 419         /*
 420          * The only thing we want back from krb5_sendauth is an error status
 421          * and any error messages.
 422          */
 423         if (code = krb5_sendauth((krb5_pointer) & sock,
 424                                                          PG_KRB5_VERSION,
 425                                                          client,
 426                                                          server,
 427                                                          (krb5_flags) 0,
 428                                                          (krb5_checksum *) NULL,
 429                                                          (krb5_creds *) NULL,
 430                                                          ccache,
 431                                                          (krb5_int32 *) NULL,
 432                                                          (krb5_keyblock **) NULL,
 433                                                          &error,
 434                                                          (krb5_ap_rep_enc_part **) NULL))
 435         {
 436                 if ((code == KRB5_SENDAUTH_REJECTED) && error)
 437                 {
 438                         (void) sprintf(PQerrormsg,
 439                                   "pg_krb5_sendauth: authentication rejected: \"%*s\"\n",
 440                                                    error->text.length, error->text.data);
 441                 }
 442                 else
 443                 {
 444                         (void) sprintf(PQerrormsg,
 445                                                    "pg_krb5_sendauth: Kerberos error %d in krb5_sendauth\n", code);
 446                         com_err("pg_krb5_sendauth", code, "in krb5_sendauth");
 447                 }
 448         }
 449         krb5_free_principal(client);
 450         krb5_free_principal(server);
 451         return code ? STATUS_ERROR : STATUS_OK;
 452 }
 453
 454 #endif   /* KRB5 */
 455
 456 static int
 457 pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
 458 {
 459         /* Encrypt the password if needed. */
 460
 461         if (areq == AUTH_REQ_CRYPT)
 462                 password = crypt(password, conn->salt);
 463
 464         return pqPacketSend(conn, password, strlen(password) + 1);
 465 }
 466
 467 /*
 468  * fe_sendauth -- client demux routine for outgoing authentication information
 469  */
 470 int
 471 fe_sendauth(AuthRequest areq, PGconn *conn, const char *hostname,
 472                         const char *password, char *PQerrormsg)
 473 {
 474         switch (areq)
 475         {
 476                         case AUTH_REQ_OK:
 477                         break;
 478
 479                 case AUTH_REQ_KRB4:
 480 #ifdef KRB4
 481                         if (pg_krb4_sendauth(PQerrormsg, conn->sock, &conn->laddr.in,
 482                                                                  &conn->raddr.in,
 483                                                                  hostname) != STATUS_OK)
 484                         {
 485                                 (void) sprintf(PQerrormsg,
 486                                                         "fe_sendauth: krb4 authentication failed\n");
 487                                 return STATUS_ERROR;
 488                         }
 489                         break;
 490 #else
 491                         (void) sprintf(PQerrormsg,
 492                                          "fe_sendauth: krb4 authentication not supported\n");
 493                         return STATUS_ERROR;
 494 #endif
 495
 496                 case AUTH_REQ_KRB5:
 497 #ifdef KRB5
 498                         if (pg_krb5_sendauth(PQerrormsg, conn->sock, &conn->laddr.in,
 499                                                                  &conn->raddr.in,
 500                                                                  hostname) != STATUS_OK)
 501                         {
 502                                 (void) sprintf(PQerrormsg,
 503                                                         "fe_sendauth: krb5 authentication failed\n");
 504                                 return STATUS_ERROR;
 505                         }
 506                         break;
 507 #else
 508                         (void) sprintf(PQerrormsg,
 509                                          "fe_sendauth: krb5 authentication not supported\n");
 510                         return STATUS_ERROR;
 511 #endif
 512
 513                 case AUTH_REQ_PASSWORD:
 514                 case AUTH_REQ_CRYPT:
 515                         if (password == NULL || *password == '\0')
 516                         {
 517                                 (void) sprintf(PQerrormsg,
 518                                                            "fe_sendauth: no password supplied\n");
 519                                 return STATUS_ERROR;
 520                         }
 521                         if (pg_password_sendauth(conn, password, areq) != STATUS_OK)
 522                         {
 523                                 (void) sprintf(PQerrormsg,
 524                                  "fe_sendauth: error sending password authentication\n");
 525                                 return STATUS_ERROR;
 526                         }
 527
 528                         break;
 529
 530                 default:
 531                         (void) sprintf(PQerrormsg,
 532                         "fe_sendauth: authentication type %u not supported\n", areq);
 533                         return STATUS_ERROR;
 534         }
 535
 536         return STATUS_OK;
 537 }
 538
 539 /*
 540  * fe_setauthsvc
 541  * fe_getauthsvc
 542  *
 543  * Set/return the authentication service currently selected for use by the
 544  * frontend. (You can only use one in the frontend, obviously.)
 545  */
 546 static int      pg_authsvc = -1;
 547
 548 void
 549 fe_setauthsvc(const char *name, char *PQerrormsg)
 550 {
 551         int                     i;
 552
 553         for (i = 0; i < n_authsvcs; ++i)
 554                 if (!strcmp(name, authsvcs[i].name))
 555                 {
 556                         pg_authsvc = i;
 557                         break;
 558                 }
 559         if (i == n_authsvcs)
 560         {
 561                 (void) sprintf(PQerrormsg,
 562                                            "fe_setauthsvc: invalid name: %s, ignoring...\n",
 563                                            name);
 564         }
 565         return;
 566 }
 567
 568 MsgType
 569 fe_getauthsvc(char *PQerrormsg)
 570 {
 571         if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
 572                 fe_setauthsvc(DEFAULT_CLIENT_AUTHSVC, PQerrormsg);
 573         return authsvcs[pg_authsvc].msgtype;
 574 }
 575
 576 /*
 577  * fe_getauthname -- returns a pointer to dynamic space containing whatever
 578  *                                       name the user has authenticated to the system
 579  * if there is an error, return the error message in PQerrormsg
 580  */
 581 char *
 582 fe_getauthname(char *PQerrormsg)
 583 {
 584         char       *name = (char *) NULL;
 585         char       *authn = (char *) NULL;
 586         MsgType         authsvc;
 587
 588         authsvc = fe_getauthsvc(PQerrormsg);
 589         switch ((int) authsvc)
 590         {
 591 #ifdef KRB4
 592                 case STARTUP_KRB4_MSG:
 593                         name = pg_krb4_authname(PQerrormsg);
 594                         break;
 595 #endif
 596 #ifdef KRB5
 597                 case STARTUP_KRB5_MSG:
 598                         name = pg_krb5_authname(PQerrormsg);
 599                         break;
 600 #endif
 601                 case STARTUP_MSG:
 602                         {
 603 #ifdef WIN32
 604                                 char            username[128];
 605                                 DWORD           namesize = sizeof(username) - 1;
 606
 607                                 if (GetUserName(username, &namesize))
 608                                         name = username;
 609 #else
 610                                 struct passwd *pw = getpwuid(geteuid());
 611
 612                                 if (pw)
 613                                         name = pw->pw_name;
 614 #endif
 615                         }
 616                         break;
 617                 default:
 618                         (void) sprintf(PQerrormsg,
 619                                    "fe_getauthname: invalid authentication system: %d\n",
 620                                                    authsvc);
 621                         break;
 622         }
 623
 624         if (name && (authn = (char *) malloc(strlen(name) + 1)))
 625                 strcpy(authn, name);
 626         return authn;
 627 }