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  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  * NOTE: the error message strings returned by this module must not
  10  * exceed INITIAL_EXPBUFFER_SIZE (currently 256 bytes).
  11  *
  12  * IDENTIFICATION
  13  *        $PostgreSQL: pgsql/src/interfaces/libpq/fe-auth.c,v 1.98 2005/01/04 23:18:25 tgl Exp $
  14  *
  15  *-------------------------------------------------------------------------
  16  */
  17
  18 /*
  19  * INTERFACE ROUTINES
  20  *         frontend (client) routines:
  21  *              fe_sendauth                             send authentication information
  22  *              fe_getauthname                  get user's name according to the client side
  23  *                                                              of the authentication system
  24  *              fe_setauthsvc                   set frontend authentication service
  25  *              fe_getauthsvc                   get current frontend authentication service
  26  *
  27  *
  28  *
  29  */
  30
  31 #include "postgres_fe.h"
  32
  33 #ifdef WIN32
  34 #include "win32.h"
  35 #else
  36 #include <unistd.h>
  37 #include <fcntl.h>
  38 #include <errno.h>
  39 #include <sys/types.h>
  40 #include <sys/param.h>                  /* for MAXHOSTNAMELEN on most */
  41 #include <sys/socket.h>
  42 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
  43 #include <sys/uio.h>
  44 #include <sys/ucred.h>
  45 #endif
  46 #ifndef  MAXHOSTNAMELEN
  47 #include <netdb.h>                              /* for MAXHOSTNAMELEN on some */
  48 #endif
  49 #include <pwd.h>
  50 #endif
  51
  52 #ifdef HAVE_CRYPT_H
  53 #include <crypt.h>
  54 #endif
  55
  56 #include "libpq-fe.h"
  57 #include "libpq-int.h"
  58 #include "fe-auth.h"
  59 #include "libpq/crypt.h"
  60
  61
  62 /*
  63  * common definitions for generic fe/be routines
  64  */
  65
  66 #define STARTUP_MSG             7               /* Initialise a connection */
  67 #define STARTUP_KRB4_MSG        10      /* krb4 session follows */
  68 #define STARTUP_KRB5_MSG        11      /* krb5 session follows */
  69 #define STARTUP_PASSWORD_MSG    14              /* Password follows */
  70
  71 struct authsvc
  72 {
  73         const char *name;                       /* service nickname (for command line) */
  74         MsgType         msgtype;                /* startup packet header type */
  75         int                     allowed;                /* initially allowed (before command line
  76                                                                  * option parsing)? */
  77 };
  78
  79 /*
  80  * Command-line parsing routines use this structure to map nicknames
  81  * onto service types (and the startup packets to use with them).
  82  *
  83  * Programs receiving an authentication request use this structure to
  84  * decide which authentication service types are currently permitted.
  85  * By default, all authentication systems compiled into the system are
  86  * allowed.  Unauthenticated connections are disallowed unless there
  87  * isn't any authentication system.
  88  */
  89 static const struct authsvc authsvcs[] = {
  90 #ifdef KRB4
  91         {"krb4", STARTUP_KRB4_MSG, 1},
  92         {"kerberos", STARTUP_KRB4_MSG, 1},
  93 #endif   /* KRB4 */
  94 #ifdef KRB5
  95         {"krb5", STARTUP_KRB5_MSG, 1},
  96         {"kerberos", STARTUP_KRB5_MSG, 1},
  97 #endif   /* KRB5 */
  98         {UNAUTHNAME, STARTUP_MSG,
  99 #if defined(KRB4) || defined(KRB5)
 100                 0
 101 #else                                                   /* !(KRB4 || KRB5) */
 102                 1
 103 #endif   /* !(KRB4 || KRB5) */
 104         },
 105         {"password", STARTUP_PASSWORD_MSG, 0}
 106 };
 107
 108 static const int n_authsvcs = sizeof(authsvcs) / sizeof(struct authsvc);
 109
 110 #ifdef KRB4
 111 /*
 112  * MIT Kerberos authentication system - protocol version 4
 113  */
 114
 115 #include "krb.h"
 116
 117 /* for some reason, this is not defined in krb.h ... */
 118 extern char *tkt_string(void);
 119
 120 /*
 121  * pg_krb4_init -- initialization performed before any Kerberos calls are made
 122  *
 123  * For v4, all we need to do is make sure the library routines get the right
 124  * ticket file if we want them to see a special one.  (They will open the file
 125  * themselves.)
 126  */
 127 static void
 128 pg_krb4_init()
 129 {
 130         char       *realm;
 131         static int      init_done = 0;
 132
 133         if (init_done)
 134                 return;
 135         init_done = 1;
 136
 137         /*
 138          * If the user set PGREALM, then we use a ticket file with a special
 139          * name: <usual-ticket-file-name>@<PGREALM-value>
 140          */
 141         if ((realm = getenv("PGREALM")))
 142         {
 143                 char            tktbuf[MAXPGPATH];
 144
 145                 (void) snprintf(tktbuf, sizeof(tktbuf), "%s@%s", tkt_string(), realm);
 146                 krb_set_tkt_string(tktbuf);
 147         }
 148 }
 149
 150 /*
 151  * pg_krb4_authname -- returns a pointer to static space containing whatever
 152  *                                         name the user has authenticated to the system
 153  *
 154  * We obtain this information by digging around in the ticket file.
 155  */
 156 static char *
 157 pg_krb4_authname(char *PQerrormsg)
 158 {
 159         char            instance[INST_SZ + 1];
 160         char            realm[REALM_SZ + 1];
 161         int                     status;
 162         static char name[SNAME_SZ + 1] = "";
 163
 164         if (name[0])
 165                 return name;
 166
 167         pg_krb4_init();
 168
 169         name[SNAME_SZ] = '\0';
 170         status = krb_get_tf_fullname(tkt_string(), name, instance, realm);
 171         if (status != KSUCCESS)
 172         {
 173                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 174                                  "pg_krb4_authname: krb_get_tf_fullname: %s\n",
 175                                  krb_err_txt[status]);
 176                 return NULL;
 177         }
 178         return name;
 179 }
 180
 181 /*
 182  * pg_krb4_sendauth -- client routine to send authentication information to
 183  *                                         the server
 184  *
 185  * This routine does not do mutual authentication, nor does it return enough
 186  * information to do encrypted connections.  But then, if we want to do
 187  * encrypted connections, we'll have to redesign the whole RPC mechanism
 188  * anyway.
 189  *
 190  * If the user is too lazy to feed us a hostname, we try to come up with
 191  * something other than "localhost" since the hostname is used as an
 192  * instance and instance names in v4 databases are usually actual hostnames
 193  * (canonicalized to omit all domain suffixes).
 194  */
 195 static int
 196 pg_krb4_sendauth(char *PQerrormsg, int sock,
 197                                  struct sockaddr_in * laddr,
 198                                  struct sockaddr_in * raddr,
 199                                  const char *hostname)
 200 {
 201         long            krbopts = 0;    /* one-way authentication */
 202         KTEXT_ST        clttkt;
 203         int                     status;
 204         char            hostbuf[MAXHOSTNAMELEN];
 205         const char *realm = getenv("PGREALM");          /* NULL == current realm */
 206
 207         if (!hostname || !(*hostname))
 208         {
 209                 if (gethostname(hostbuf, MAXHOSTNAMELEN) < 0)
 210                         strcpy(hostbuf, "localhost");
 211                 hostname = hostbuf;
 212         }
 213
 214         pg_krb4_init();
 215
 216         status = krb_sendauth(krbopts,
 217                                                   sock,
 218                                                   &clttkt,
 219                                                   PG_KRB_SRVNAM,
 220                                                   hostname,
 221                                                   realm,
 222                                                   (u_long) 0,
 223                                                   NULL,
 224                                                   NULL,
 225                                                   NULL,
 226                                                   laddr,
 227                                                   raddr,
 228                                                   PG_KRB4_VERSION);
 229         if (status != KSUCCESS)
 230         {
 231                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 232                                  libpq_gettext("Kerberos 4 error: %s\n"),
 233                                  krb_err_txt[status]);
 234                 return STATUS_ERROR;
 235         }
 236         return STATUS_OK;
 237 }
 238 #endif   /* KRB4 */
 239
 240 #ifdef KRB5
 241 /*
 242  * MIT Kerberos authentication system - protocol version 5
 243  */
 244
 245 #include <krb5.h>
 246
 247 /*
 248  * pg_an_to_ln -- return the local name corresponding to an authentication
 249  *                                name
 250  *
 251  * XXX Assumes that the first aname component is the user name.  This is NOT
 252  *         necessarily so, since an aname can actually be something out of your
 253  *         worst X.400 nightmare, like
 254  *                ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
 255  *         Note that the MIT an_to_ln code does the same thing if you don't
 256  *         provide an aname mapping database...it may be a better idea to use
 257  *         krb5_an_to_ln, except that it punts if multiple components are found,
 258  *         and we can't afford to punt.
 259  */
 260 static char *
 261 pg_an_to_ln(char *aname)
 262 {
 263         char       *p;
 264
 265         if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
 266                 *p = '\0';
 267         return aname;
 268 }
 269
 270
 271 /*
 272  * Various krb5 state which is not connection specific, and a flag to
 273  * indicate whether we have initialised it yet.
 274  */
 275 static int      pg_krb5_initialised;
 276 static krb5_context pg_krb5_context;
 277 static krb5_ccache pg_krb5_ccache;
 278 static krb5_principal pg_krb5_client;
 279 static char *pg_krb5_name;
 280
 281
 282 static int
 283 pg_krb5_init(char *PQerrormsg)
 284 {
 285         krb5_error_code retval;
 286
 287         if (pg_krb5_initialised)
 288                 return STATUS_OK;
 289
 290         retval = krb5_init_context(&pg_krb5_context);
 291         if (retval)
 292         {
 293                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 294                                  "pg_krb5_init: krb5_init_context: %s\n",
 295                                  error_message(retval));
 296                 return STATUS_ERROR;
 297         }
 298
 299         retval = krb5_cc_default(pg_krb5_context, &pg_krb5_ccache);
 300         if (retval)
 301         {
 302                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 303                                  "pg_krb5_init: krb5_cc_default: %s\n",
 304                                  error_message(retval));
 305                 krb5_free_context(pg_krb5_context);
 306                 return STATUS_ERROR;
 307         }
 308
 309         retval = krb5_cc_get_principal(pg_krb5_context, pg_krb5_ccache,
 310                                                                    &pg_krb5_client);
 311         if (retval)
 312         {
 313                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 314                                  "pg_krb5_init: krb5_cc_get_principal: %s\n",
 315                                  error_message(retval));
 316                 krb5_cc_close(pg_krb5_context, pg_krb5_ccache);
 317                 krb5_free_context(pg_krb5_context);
 318                 return STATUS_ERROR;
 319         }
 320
 321         retval = krb5_unparse_name(pg_krb5_context, pg_krb5_client, &pg_krb5_name);
 322         if (retval)
 323         {
 324                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 325                                  "pg_krb5_init: krb5_unparse_name: %s\n",
 326                                  error_message(retval));
 327                 krb5_free_principal(pg_krb5_context, pg_krb5_client);
 328                 krb5_cc_close(pg_krb5_context, pg_krb5_ccache);
 329                 krb5_free_context(pg_krb5_context);
 330                 return STATUS_ERROR;
 331         }
 332
 333         pg_krb5_name = pg_an_to_ln(pg_krb5_name);
 334
 335         pg_krb5_initialised = 1;
 336         return STATUS_OK;
 337 }
 338
 339
 340 /*
 341  * pg_krb5_authname -- returns a pointer to static space containing whatever
 342  *                                         name the user has authenticated to the system
 343   */
 344 static const char *
 345 pg_krb5_authname(char *PQerrormsg)
 346 {
 347         if (pg_krb5_init(PQerrormsg) != STATUS_OK)
 348                 return NULL;
 349
 350         return pg_krb5_name;
 351 }
 352
 353
 354 /*
 355  * pg_krb5_sendauth -- client routine to send authentication information to
 356  *                                         the server
 357  */
 358 static int
 359 pg_krb5_sendauth(char *PQerrormsg, int sock, const char *hostname)
 360 {
 361         krb5_error_code retval;
 362         int                     ret;
 363         krb5_principal server;
 364         krb5_auth_context auth_context = NULL;
 365         krb5_error *err_ret = NULL;
 366         int                     flags;
 367
 368         ret = pg_krb5_init(PQerrormsg);
 369         if (ret != STATUS_OK)
 370                 return ret;
 371
 372         retval = krb5_sname_to_principal(pg_krb5_context, hostname, PG_KRB_SRVNAM,
 373                                                                          KRB5_NT_SRV_HST, &server);
 374         if (retval)
 375         {
 376                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 377                                  "pg_krb5_sendauth: krb5_sname_to_principal: %s\n",
 378                                  error_message(retval));
 379                 return STATUS_ERROR;
 380         }
 381
 382         /*
 383          * libpq uses a non-blocking socket. But kerberos needs a blocking
 384          * socket, and we have to block somehow to do mutual authentication
 385          * anyway. So we temporarily make it blocking.
 386          */
 387         flags = fcntl(sock, F_GETFL);
 388         if (flags < 0 || fcntl(sock, F_SETFL, (long) (flags & ~O_NONBLOCK)))
 389         {
 390                 char            sebuf[256];
 391
 392                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 393                                  libpq_gettext("could not set socket to blocking mode: %s\n"), pqStrerror(errno, sebuf, sizeof(sebuf)));
 394                 krb5_free_principal(pg_krb5_context, server);
 395                 return STATUS_ERROR;
 396         }
 397
 398         retval = krb5_sendauth(pg_krb5_context, &auth_context,
 399                                                    (krb5_pointer) & sock, PG_KRB_SRVNAM,
 400                                                    pg_krb5_client, server,
 401                                                    AP_OPTS_MUTUAL_REQUIRED,
 402                                                    NULL, 0,             /* no creds, use ccache instead */
 403                                                    pg_krb5_ccache, &err_ret, NULL, NULL);
 404         if (retval)
 405         {
 406                 if (retval == KRB5_SENDAUTH_REJECTED && err_ret)
 407                 {
 408 #if defined(HAVE_KRB5_ERROR_TEXT_DATA)
 409                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 410                           libpq_gettext("Kerberos 5 authentication rejected: %*s\n"),
 411                                          (int) err_ret->text.length, err_ret->text.data);
 412 #elif defined(HAVE_KRB5_ERROR_E_DATA)
 413                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 414                           libpq_gettext("Kerberos 5 authentication rejected: %*s\n"),
 415                                          (int) err_ret->e_data->length,
 416                                          (const char *) err_ret->e_data->data);
 417 #else
 418 #error "bogus configuration"
 419 #endif
 420                 }
 421                 else
 422                 {
 423                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 424                                          "krb5_sendauth: %s\n", error_message(retval));
 425                 }
 426
 427                 if (err_ret)
 428                         krb5_free_error(pg_krb5_context, err_ret);
 429
 430                 ret = STATUS_ERROR;
 431         }
 432
 433         krb5_free_principal(pg_krb5_context, server);
 434
 435         if (fcntl(sock, F_SETFL, (long) flags))
 436         {
 437                 char            sebuf[256];
 438
 439                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 440                                  libpq_gettext("could not restore non-blocking mode on socket: %s\n"),
 441                                  pqStrerror(errno, sebuf, sizeof(sebuf)));
 442                 ret = STATUS_ERROR;
 443         }
 444
 445         return ret;
 446 }
 447 #endif   /* KRB5 */
 448
 449 /*
 450  * Respond to AUTH_REQ_SCM_CREDS challenge.
 451  *
 452  * Note: current backends will not use this challenge if HAVE_GETPEEREID
 453  * or SO_PEERCRED is defined, but pre-7.4 backends might, so compile the
 454  * code anyway.
 455  */
 456 static int
 457 pg_local_sendauth(char *PQerrormsg, PGconn *conn)
 458 {
 459 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || \
 460         (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS))
 461         char            buf;
 462         struct iovec iov;
 463         struct msghdr msg;
 464
 465 #ifdef HAVE_STRUCT_CMSGCRED
 466         /* Prevent padding */
 467         char            cmsgmem[sizeof(struct cmsghdr) + sizeof(struct cmsgcred)];
 468
 469         /* Point to start of first structure */
 470         struct cmsghdr *cmsg = (struct cmsghdr *) cmsgmem;
 471 #endif
 472
 473         /*
 474          * The backend doesn't care what we send here, but it wants exactly
 475          * one character to force recvmsg() to block and wait for us.
 476          */
 477         buf = '\0';
 478         iov.iov_base = &buf;
 479         iov.iov_len = 1;
 480
 481         memset(&msg, 0, sizeof(msg));
 482         msg.msg_iov = &iov;
 483         msg.msg_iovlen = 1;
 484
 485 #ifdef HAVE_STRUCT_CMSGCRED
 486         /* Create control header, FreeBSD */
 487         msg.msg_control = cmsg;
 488         msg.msg_controllen = sizeof(cmsgmem);
 489         memset(cmsg, 0, sizeof(cmsgmem));
 490         cmsg->cmsg_len = sizeof(cmsgmem);
 491         cmsg->cmsg_level = SOL_SOCKET;
 492         cmsg->cmsg_type = SCM_CREDS;
 493 #endif
 494
 495         if (sendmsg(conn->sock, &msg, 0) == -1)
 496         {
 497                 char            sebuf[256];
 498
 499                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 500                                  "pg_local_sendauth: sendmsg: %s\n",
 501                                  pqStrerror(errno, sebuf, sizeof(sebuf)));
 502                 return STATUS_ERROR;
 503         }
 504         return STATUS_OK;
 505 #else
 506         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 507                 libpq_gettext("SCM_CRED authentication method not supported\n"));
 508         return STATUS_ERROR;
 509 #endif
 510 }
 511
 512 static int
 513 pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
 514 {
 515         int                     ret;
 516         char       *crypt_pwd;
 517
 518         /* Encrypt the password if needed. */
 519
 520         switch (areq)
 521         {
 522                 case AUTH_REQ_MD5:
 523                         {
 524                                 char       *crypt_pwd2;
 525
 526                                 if (!(crypt_pwd = malloc(MD5_PASSWD_LEN + 1)) ||
 527                                         !(crypt_pwd2 = malloc(MD5_PASSWD_LEN + 1)))
 528                                 {
 529                                         fprintf(stderr, libpq_gettext("out of memory\n"));
 530                                         return STATUS_ERROR;
 531                                 }
 532                                 if (!EncryptMD5(password, conn->pguser,
 533                                                                 strlen(conn->pguser), crypt_pwd2))
 534                                 {
 535                                         free(crypt_pwd);
 536                                         free(crypt_pwd2);
 537                                         return STATUS_ERROR;
 538                                 }
 539                                 if (!EncryptMD5(crypt_pwd2 + strlen("md5"), conn->md5Salt,
 540                                                                 sizeof(conn->md5Salt), crypt_pwd))
 541                                 {
 542                                         free(crypt_pwd);
 543                                         free(crypt_pwd2);
 544                                         return STATUS_ERROR;
 545                                 }
 546                                 free(crypt_pwd2);
 547                                 break;
 548                         }
 549                 case AUTH_REQ_CRYPT:
 550                         {
 551                                 char            salt[3];
 552
 553                                 StrNCpy(salt, conn->cryptSalt, 3);
 554                                 crypt_pwd = crypt(password, salt);
 555                                 break;
 556                         }
 557                 case AUTH_REQ_PASSWORD:
 558                         /* discard const so we can assign it */
 559                         crypt_pwd = (char *) password;
 560                         break;
 561                 default:
 562                         return STATUS_ERROR;
 563         }
 564         /* Packet has a message type as of protocol 3.0 */
 565         if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3)
 566                 ret = pqPacketSend(conn, 'p', crypt_pwd, strlen(crypt_pwd) + 1);
 567         else
 568                 ret = pqPacketSend(conn, 0, crypt_pwd, strlen(crypt_pwd) + 1);
 569         if (areq == AUTH_REQ_MD5)
 570                 free(crypt_pwd);
 571         return ret;
 572 }
 573
 574 /*
 575  * fe_sendauth -- client demux routine for outgoing authentication information
 576  */
 577 int
 578 fe_sendauth(AuthRequest areq, PGconn *conn, const char *hostname,
 579                         const char *password, char *PQerrormsg)
 580 {
 581 #if !defined(KRB4) && !defined(KRB5)
 582         (void) hostname;                        /* not used */
 583 #endif
 584
 585         switch (areq)
 586         {
 587                 case AUTH_REQ_OK:
 588                         break;
 589
 590                 case AUTH_REQ_KRB4:
 591 #ifdef KRB4
 592                         pglock_thread();
 593                         if (pg_krb4_sendauth(PQerrormsg, conn->sock,
 594                                                            (struct sockaddr_in *) & conn->laddr.addr,
 595                                                            (struct sockaddr_in *) & conn->raddr.addr,
 596                                                                  hostname) != STATUS_OK)
 597                         {
 598                                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 599                                         libpq_gettext("Kerberos 4 authentication failed\n"));
 600                                 pgunlock_thread();
 601                                 return STATUS_ERROR;
 602                         }
 603                         pgunlock_thread();
 604                         break;
 605 #else
 606                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 607                          libpq_gettext("Kerberos 4 authentication not supported\n"));
 608                         return STATUS_ERROR;
 609 #endif
 610
 611                 case AUTH_REQ_KRB5:
 612 #ifdef KRB5
 613                         pglock_thread();
 614                         if (pg_krb5_sendauth(PQerrormsg, conn->sock,
 615                                                                  hostname) != STATUS_OK)
 616                         {
 617                                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 618                                         libpq_gettext("Kerberos 5 authentication failed\n"));
 619                                 pgunlock_thread();
 620                                 return STATUS_ERROR;
 621                         }
 622                         pgunlock_thread();
 623                         break;
 624 #else
 625                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 626                          libpq_gettext("Kerberos 5 authentication not supported\n"));
 627                         return STATUS_ERROR;
 628 #endif
 629
 630                 case AUTH_REQ_MD5:
 631                 case AUTH_REQ_CRYPT:
 632                 case AUTH_REQ_PASSWORD:
 633                         if (password == NULL || *password == '\0')
 634                         {
 635                                 (void) snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 636                                                                 PQnoPasswordSupplied);
 637                                 return STATUS_ERROR;
 638                         }
 639                         if (pg_password_sendauth(conn, password, areq) != STATUS_OK)
 640                         {
 641                                 (void) snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 642                                  "fe_sendauth: error sending password authentication\n");
 643                                 return STATUS_ERROR;
 644                         }
 645                         break;
 646
 647                 case AUTH_REQ_SCM_CREDS:
 648                         if (pg_local_sendauth(PQerrormsg, conn) != STATUS_OK)
 649                                 return STATUS_ERROR;
 650                         break;
 651
 652                 default:
 653                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 654                                          libpq_gettext("authentication method %u not supported\n"), areq);
 655                         return STATUS_ERROR;
 656         }
 657
 658         return STATUS_OK;
 659 }
 660
 661 /*
 662  * fe_setauthsvc
 663  * fe_getauthsvc
 664  *
 665  * Set/return the authentication service currently selected for use by the
 666  * frontend. (You can only use one in the frontend, obviously.)
 667  *
 668  * NB: This is not thread-safe if different threads try to select different
 669  * authentication services!  It's OK for fe_getauthsvc to select the default,
 670  * since that will be the same for all threads, but direct application use
 671  * of fe_setauthsvc is not thread-safe.  However, use of fe_setauthsvc is
 672  * deprecated anyway...
 673  */
 674
 675 static int      pg_authsvc = -1;
 676
 677 void
 678 fe_setauthsvc(const char *name, char *PQerrormsg)
 679 {
 680         int                     i;
 681
 682         for (i = 0; i < n_authsvcs; ++i)
 683                 if (strcmp(name, authsvcs[i].name) == 0)
 684                 {
 685                         pg_authsvc = i;
 686                         break;
 687                 }
 688         if (i == n_authsvcs)
 689         {
 690                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 691                                  libpq_gettext("invalid authentication service name \"%s\", ignored\n"),
 692                                  name);
 693         }
 694         return;
 695 }
 696
 697 MsgType
 698 fe_getauthsvc(char *PQerrormsg)
 699 {
 700         if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
 701         {
 702                 fe_setauthsvc(DEFAULT_CLIENT_AUTHSVC, PQerrormsg);
 703                 if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
 704                 {
 705                         /* Can only get here if DEFAULT_CLIENT_AUTHSVC is misdefined */
 706                         return 0;
 707                 }
 708         }
 709         return authsvcs[pg_authsvc].msgtype;
 710 }
 711
 712 /*
 713  * fe_getauthname -- returns a pointer to dynamic space containing whatever
 714  *                                       name the user has authenticated to the system
 715  * if there is an error, return the error message in PQerrormsg
 716  */
 717 char *
 718 fe_getauthname(char *PQerrormsg)
 719 {
 720         const char *name = NULL;
 721         char       *authn;
 722         MsgType         authsvc;
 723 #ifdef WIN32
 724         char            username[128];
 725         DWORD           namesize = sizeof(username) - 1;
 726 #else
 727         char            pwdbuf[BUFSIZ];
 728         struct passwd pwdstr;
 729         struct passwd *pw = NULL;
 730 #endif
 731
 732         authsvc = fe_getauthsvc(PQerrormsg);
 733
 734         /* this just guards against broken DEFAULT_CLIENT_AUTHSVC, see above */
 735         if (authsvc == 0)
 736                 return NULL;                    /* leave original error message in place */
 737
 738         pglock_thread();
 739
 740 #ifdef KRB4
 741         if (authsvc == STARTUP_KRB4_MSG)
 742                 name = pg_krb4_authname(PQerrormsg);
 743 #endif
 744 #ifdef KRB5
 745         if (authsvc == STARTUP_KRB5_MSG)
 746                 name = pg_krb5_authname(PQerrormsg);
 747 #endif
 748
 749         if (authsvc == STARTUP_MSG
 750                 || (authsvc == STARTUP_KRB4_MSG && !name)
 751                 || (authsvc == STARTUP_KRB5_MSG && !name))
 752         {
 753 #ifdef WIN32
 754                 if (GetUserName(username, &namesize))
 755                         name = username;
 756 #else
 757                 if (pqGetpwuid(geteuid(), &pwdstr, pwdbuf, sizeof(pwdbuf), &pw) == 0)
 758                         name = pw->pw_name;
 759 #endif
 760         }
 761
 762         if (authsvc != STARTUP_MSG && authsvc != STARTUP_KRB4_MSG && authsvc != STARTUP_KRB5_MSG)
 763                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 764                                  libpq_gettext("fe_getauthname: invalid authentication system: %d\n"),
 765                                  authsvc);
 766
 767         authn = name ? strdup(name) : NULL;
 768
 769         pgunlock_thread();
 770
 771         return authn;
 772 }