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) 1996-2004, 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 1.94 2004/10/16 03:10:17 momjian 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 #include <com_err.h>
 247
 248 /*
 249  * pg_an_to_ln -- return the local name corresponding to an authentication
 250  *                                name
 251  *
 252  * XXX Assumes that the first aname component is the user name.  This is NOT
 253  *         necessarily so, since an aname can actually be something out of your
 254  *         worst X.400 nightmare, like
 255  *                ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
 256  *         Note that the MIT an_to_ln code does the same thing if you don't
 257  *         provide an aname mapping database...it may be a better idea to use
 258  *         krb5_an_to_ln, except that it punts if multiple components are found,
 259  *         and we can't afford to punt.
 260  */
 261 static char *
 262 pg_an_to_ln(char *aname)
 263 {
 264         char       *p;
 265
 266         if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
 267                 *p = '\0';
 268         return aname;
 269 }
 270
 271
 272 /*
 273  * Various krb5 state which is not connection specific, and a flag to
 274  * indicate whether we have initialised it yet.
 275  */
 276 static int      pg_krb5_initialised;
 277 static krb5_context pg_krb5_context;
 278 static krb5_ccache pg_krb5_ccache;
 279 static krb5_principal pg_krb5_client;
 280 static char *pg_krb5_name;
 281
 282
 283 static int
 284 pg_krb5_init(char *PQerrormsg)
 285 {
 286         krb5_error_code retval;
 287
 288         if (pg_krb5_initialised)
 289                 return STATUS_OK;
 290
 291         retval = krb5_init_context(&pg_krb5_context);
 292         if (retval)
 293         {
 294                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 295                                  "pg_krb5_init: krb5_init_context: %s\n",
 296                                  error_message(retval));
 297                 return STATUS_ERROR;
 298         }
 299
 300         retval = krb5_cc_default(pg_krb5_context, &pg_krb5_ccache);
 301         if (retval)
 302         {
 303                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 304                                  "pg_krb5_init: krb5_cc_default: %s\n",
 305                                  error_message(retval));
 306                 krb5_free_context(pg_krb5_context);
 307                 return STATUS_ERROR;
 308         }
 309
 310         retval = krb5_cc_get_principal(pg_krb5_context, pg_krb5_ccache,
 311                                                                    &pg_krb5_client);
 312         if (retval)
 313         {
 314                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 315                                  "pg_krb5_init: krb5_cc_get_principal: %s\n",
 316                                  error_message(retval));
 317                 krb5_cc_close(pg_krb5_context, pg_krb5_ccache);
 318                 krb5_free_context(pg_krb5_context);
 319                 return STATUS_ERROR;
 320         }
 321
 322         retval = krb5_unparse_name(pg_krb5_context, pg_krb5_client, &pg_krb5_name);
 323         if (retval)
 324         {
 325                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 326                                  "pg_krb5_init: krb5_unparse_name: %s\n",
 327                                  error_message(retval));
 328                 krb5_free_principal(pg_krb5_context, pg_krb5_client);
 329                 krb5_cc_close(pg_krb5_context, pg_krb5_ccache);
 330                 krb5_free_context(pg_krb5_context);
 331                 return STATUS_ERROR;
 332         }
 333
 334         pg_krb5_name = pg_an_to_ln(pg_krb5_name);
 335
 336         pg_krb5_initialised = 1;
 337         return STATUS_OK;
 338 }
 339
 340
 341 /*
 342  * pg_krb5_authname -- returns a pointer to static space containing whatever
 343  *                                         name the user has authenticated to the system
 344   */
 345 static const char *
 346 pg_krb5_authname(char *PQerrormsg)
 347 {
 348         if (pg_krb5_init(PQerrormsg) != STATUS_OK)
 349                 return NULL;
 350
 351         return pg_krb5_name;
 352 }
 353
 354
 355 /*
 356  * pg_krb5_sendauth -- client routine to send authentication information to
 357  *                                         the server
 358  */
 359 static int
 360 pg_krb5_sendauth(char *PQerrormsg, int sock, const char *hostname)
 361 {
 362         krb5_error_code retval;
 363         int                     ret;
 364         krb5_principal server;
 365         krb5_auth_context auth_context = NULL;
 366         krb5_error *err_ret = NULL;
 367         int                     flags;
 368
 369         ret = pg_krb5_init(PQerrormsg);
 370         if (ret != STATUS_OK)
 371                 return ret;
 372
 373         retval = krb5_sname_to_principal(pg_krb5_context, hostname, PG_KRB_SRVNAM,
 374                                                                          KRB5_NT_SRV_HST, &server);
 375         if (retval)
 376         {
 377                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 378                                  "pg_krb5_sendauth: krb5_sname_to_principal: %s\n",
 379                                  error_message(retval));
 380                 return STATUS_ERROR;
 381         }
 382
 383         /*
 384          * libpq uses a non-blocking socket. But kerberos needs a blocking
 385          * socket, and we have to block somehow to do mutual authentication
 386          * anyway. So we temporarily make it blocking.
 387          */
 388         flags = fcntl(sock, F_GETFL);
 389         if (flags < 0 || fcntl(sock, F_SETFL, (long) (flags & ~O_NONBLOCK)))
 390         {
 391                 char            sebuf[256];
 392
 393                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 394                                  libpq_gettext("could not set socket to blocking mode: %s\n"), pqStrerror(errno, sebuf, sizeof(sebuf)));
 395                 krb5_free_principal(pg_krb5_context, server);
 396                 return STATUS_ERROR;
 397         }
 398
 399         retval = krb5_sendauth(pg_krb5_context, &auth_context,
 400                                                    (krb5_pointer) & sock, PG_KRB_SRVNAM,
 401                                                    pg_krb5_client, server,
 402                                                    AP_OPTS_MUTUAL_REQUIRED,
 403                                                    NULL, 0,             /* no creds, use ccache instead */
 404                                                    pg_krb5_ccache, &err_ret, NULL, NULL);
 405         if (retval)
 406         {
 407                 if (retval == KRB5_SENDAUTH_REJECTED && err_ret)
 408                 {
 409 #if defined(HAVE_KRB5_ERROR_TEXT_DATA)
 410                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 411                           libpq_gettext("Kerberos 5 authentication rejected: %*s\n"),
 412                                          (int) err_ret->text.length, err_ret->text.data);
 413 #elif defined(HAVE_KRB5_ERROR_E_DATA)
 414                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 415                           libpq_gettext("Kerberos 5 authentication rejected: %*s\n"),
 416                                          (int) err_ret->e_data->length,
 417                                          (const char *) err_ret->e_data->data);
 418 #else
 419 #error "bogus configuration"
 420 #endif
 421                 }
 422                 else
 423                 {
 424                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 425                                          "krb5_sendauth: %s\n", error_message(retval));
 426                 }
 427
 428                 if (err_ret)
 429                         krb5_free_error(pg_krb5_context, err_ret);
 430
 431                 ret = STATUS_ERROR;
 432         }
 433
 434         krb5_free_principal(pg_krb5_context, server);
 435
 436         if (fcntl(sock, F_SETFL, (long) flags))
 437         {
 438                 char            sebuf[256];
 439
 440                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 441                                  libpq_gettext("could not restore non-blocking mode on socket: %s\n"),
 442                                  pqStrerror(errno, sebuf, sizeof(sebuf)));
 443                 ret = STATUS_ERROR;
 444         }
 445
 446         return ret;
 447 }
 448 #endif   /* KRB5 */
 449
 450 /*
 451  * Respond to AUTH_REQ_SCM_CREDS challenge.
 452  *
 453  * Note: current backends will not use this challenge if HAVE_GETPEEREID
 454  * or SO_PEERCRED is defined, but pre-7.4 backends might, so compile the
 455  * code anyway.
 456  */
 457 static int
 458 pg_local_sendauth(char *PQerrormsg, PGconn *conn)
 459 {
 460 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || \
 461         (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS))
 462         char            buf;
 463         struct iovec iov;
 464         struct msghdr msg;
 465
 466 #ifdef HAVE_STRUCT_CMSGCRED
 467         /* Prevent padding */
 468         char            cmsgmem[sizeof(struct cmsghdr) + sizeof(struct cmsgcred)];
 469
 470         /* Point to start of first structure */
 471         struct cmsghdr *cmsg = (struct cmsghdr *) cmsgmem;
 472 #endif
 473
 474         /*
 475          * The backend doesn't care what we send here, but it wants exactly
 476          * one character to force recvmsg() to block and wait for us.
 477          */
 478         buf = '\0';
 479         iov.iov_base = &buf;
 480         iov.iov_len = 1;
 481
 482         memset(&msg, 0, sizeof(msg));
 483         msg.msg_iov = &iov;
 484         msg.msg_iovlen = 1;
 485
 486 #ifdef HAVE_STRUCT_CMSGCRED
 487         /* Create control header, FreeBSD */
 488         msg.msg_control = cmsg;
 489         msg.msg_controllen = sizeof(cmsgmem);
 490         memset(cmsg, 0, sizeof(cmsgmem));
 491         cmsg->cmsg_len = sizeof(cmsgmem);
 492         cmsg->cmsg_level = SOL_SOCKET;
 493         cmsg->cmsg_type = SCM_CREDS;
 494 #endif
 495
 496         if (sendmsg(conn->sock, &msg, 0) == -1)
 497         {
 498                 char            sebuf[256];
 499
 500                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 501                                  "pg_local_sendauth: sendmsg: %s\n",
 502                                  pqStrerror(errno, sebuf, sizeof(sebuf)));
 503                 return STATUS_ERROR;
 504         }
 505         return STATUS_OK;
 506 #else
 507         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 508                 libpq_gettext("SCM_CRED authentication method not supported\n"));
 509         return STATUS_ERROR;
 510 #endif
 511 }
 512
 513 static int
 514 pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
 515 {
 516         int                     ret;
 517         char       *crypt_pwd;
 518
 519         /* Encrypt the password if needed. */
 520
 521         switch (areq)
 522         {
 523                 case AUTH_REQ_MD5:
 524                         {
 525                                 char       *crypt_pwd2;
 526
 527                                 if (!(crypt_pwd = malloc(MD5_PASSWD_LEN + 1)) ||
 528                                         !(crypt_pwd2 = malloc(MD5_PASSWD_LEN + 1)))
 529                                 {
 530                                         perror("malloc");
 531                                         return STATUS_ERROR;
 532                                 }
 533                                 if (!EncryptMD5(password, conn->pguser,
 534                                                                 strlen(conn->pguser), crypt_pwd2))
 535                                 {
 536                                         free(crypt_pwd);
 537                                         free(crypt_pwd2);
 538                                         return STATUS_ERROR;
 539                                 }
 540                                 if (!EncryptMD5(crypt_pwd2 + strlen("md5"), conn->md5Salt,
 541                                                                 sizeof(conn->md5Salt), crypt_pwd))
 542                                 {
 543                                         free(crypt_pwd);
 544                                         free(crypt_pwd2);
 545                                         return STATUS_ERROR;
 546                                 }
 547                                 free(crypt_pwd2);
 548                                 break;
 549                         }
 550                 case AUTH_REQ_CRYPT:
 551                         {
 552                                 char            salt[3];
 553
 554                                 StrNCpy(salt, conn->cryptSalt, 3);
 555                                 crypt_pwd = crypt(password, salt);
 556                                 break;
 557                         }
 558                 case AUTH_REQ_PASSWORD:
 559                         /* discard const so we can assign it */
 560                         crypt_pwd = (char *) password;
 561                         break;
 562                 default:
 563                         return STATUS_ERROR;
 564         }
 565         /* Packet has a message type as of protocol 3.0 */
 566         if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3)
 567                 ret = pqPacketSend(conn, 'p', crypt_pwd, strlen(crypt_pwd) + 1);
 568         else
 569                 ret = pqPacketSend(conn, 0, crypt_pwd, strlen(crypt_pwd) + 1);
 570         if (areq == AUTH_REQ_MD5)
 571                 free(crypt_pwd);
 572         return ret;
 573 }
 574
 575 /*
 576  * fe_sendauth -- client demux routine for outgoing authentication information
 577  */
 578 int
 579 fe_sendauth(AuthRequest areq, PGconn *conn, const char *hostname,
 580                         const char *password, char *PQerrormsg)
 581 {
 582 #if !defined(KRB4) && !defined(KRB5)
 583         (void) hostname;                        /* not used */
 584 #endif
 585
 586         switch (areq)
 587         {
 588                 case AUTH_REQ_OK:
 589                         break;
 590
 591                 case AUTH_REQ_KRB4:
 592 #ifdef KRB4
 593                         pglock_thread();
 594                         if (pg_krb4_sendauth(PQerrormsg, conn->sock,
 595                                                            (struct sockaddr_in *) & conn->laddr.addr,
 596                                                            (struct sockaddr_in *) & conn->raddr.addr,
 597                                                                  hostname) != STATUS_OK)
 598                         {
 599                                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 600                                         libpq_gettext("Kerberos 4 authentication failed\n"));
 601                                 pgunlock_thread();
 602                                 return STATUS_ERROR;
 603                         }
 604                         pgunlock_thread();
 605                         break;
 606 #else
 607                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 608                          libpq_gettext("Kerberos 4 authentication not supported\n"));
 609                         return STATUS_ERROR;
 610 #endif
 611
 612                 case AUTH_REQ_KRB5:
 613 #ifdef KRB5
 614                         pglock_thread();
 615                         if (pg_krb5_sendauth(PQerrormsg, conn->sock,
 616                                                                  hostname) != STATUS_OK)
 617                         {
 618                                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 619                                         libpq_gettext("Kerberos 5 authentication failed\n"));
 620                                 pgunlock_thread();
 621                                 return STATUS_ERROR;
 622                         }
 623                         pgunlock_thread();
 624                         break;
 625 #else
 626                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 627                          libpq_gettext("Kerberos 5 authentication not supported\n"));
 628                         return STATUS_ERROR;
 629 #endif
 630
 631                 case AUTH_REQ_MD5:
 632                 case AUTH_REQ_CRYPT:
 633                 case AUTH_REQ_PASSWORD:
 634                         if (password == NULL || *password == '\0')
 635                         {
 636                                 (void) snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 637                                                                 PQnoPasswordSupplied);
 638                                 return STATUS_ERROR;
 639                         }
 640                         if (pg_password_sendauth(conn, password, areq) != STATUS_OK)
 641                         {
 642                                 (void) snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 643                                  "fe_sendauth: error sending password authentication\n");
 644                                 return STATUS_ERROR;
 645                         }
 646                         break;
 647
 648                 case AUTH_REQ_SCM_CREDS:
 649                         if (pg_local_sendauth(PQerrormsg, conn) != STATUS_OK)
 650                                 return STATUS_ERROR;
 651                         break;
 652
 653                 default:
 654                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 655                                          libpq_gettext("authentication method %u not supported\n"), areq);
 656                         return STATUS_ERROR;
 657         }
 658
 659         return STATUS_OK;
 660 }
 661
 662 /*
 663  * fe_setauthsvc
 664  * fe_getauthsvc
 665  *
 666  * Set/return the authentication service currently selected for use by the
 667  * frontend. (You can only use one in the frontend, obviously.)
 668  *
 669  * NB: This is not thread-safe if different threads try to select different
 670  * authentication services!  It's OK for fe_getauthsvc to select the default,
 671  * since that will be the same for all threads, but direct application use
 672  * of fe_setauthsvc is not thread-safe.  However, use of fe_setauthsvc is
 673  * deprecated anyway...
 674  */
 675
 676 static int      pg_authsvc = -1;
 677
 678 void
 679 fe_setauthsvc(const char *name, char *PQerrormsg)
 680 {
 681         int                     i;
 682
 683         for (i = 0; i < n_authsvcs; ++i)
 684                 if (strcmp(name, authsvcs[i].name) == 0)
 685                 {
 686                         pg_authsvc = i;
 687                         break;
 688                 }
 689         if (i == n_authsvcs)
 690         {
 691                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 692                                  libpq_gettext("invalid authentication service name \"%s\", ignored\n"),
 693                                  name);
 694         }
 695         return;
 696 }
 697
 698 MsgType
 699 fe_getauthsvc(char *PQerrormsg)
 700 {
 701         if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
 702         {
 703                 fe_setauthsvc(DEFAULT_CLIENT_AUTHSVC, PQerrormsg);
 704                 if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
 705                 {
 706                         /* Can only get here if DEFAULT_CLIENT_AUTHSVC is misdefined */
 707                         return 0;
 708                 }
 709         }
 710         return authsvcs[pg_authsvc].msgtype;
 711 }
 712
 713 /*
 714  * fe_getauthname -- returns a pointer to dynamic space containing whatever
 715  *                                       name the user has authenticated to the system
 716  * if there is an error, return the error message in PQerrormsg
 717  */
 718 char *
 719 fe_getauthname(char *PQerrormsg)
 720 {
 721         const char *name = NULL;
 722         char       *authn = NULL;
 723         MsgType         authsvc;
 724
 725         authsvc = fe_getauthsvc(PQerrormsg);
 726
 727         /* this just guards against broken DEFAULT_CLIENT_AUTHSVC, see above */
 728         if (authsvc == 0)
 729                 return NULL;                    /* leave original error message in place */
 730
 731         pglock_thread();
 732 #ifdef KRB4
 733         if (authsvc == STARTUP_KRB4_MSG)
 734                 name = pg_krb4_authname(PQerrormsg);
 735 #endif
 736 #ifdef KRB5
 737         if (authsvc == STARTUP_KRB5_MSG)
 738                 name = pg_krb5_authname(PQerrormsg);
 739 #endif
 740
 741         if (authsvc == STARTUP_MSG
 742                 || (authsvc == STARTUP_KRB4_MSG && !name)
 743                 || (authsvc == STARTUP_KRB5_MSG && !name))
 744         {
 745 #ifdef WIN32
 746                 char            username[128];
 747                 DWORD           namesize = sizeof(username) - 1;
 748
 749                 if (GetUserName(username, &namesize))
 750                         name = username;
 751 #else
 752                 char            pwdbuf[BUFSIZ];
 753                 struct passwd pwdstr;
 754                 struct passwd *pw = NULL;
 755
 756                 if (pqGetpwuid(geteuid(), &pwdstr,
 757                                            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         if (name && (authn = (char *) malloc(strlen(name) + 1)))
 768                 strcpy(authn, name);
 769         pgunlock_thread();
 770         return authn;
 771 }