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 1.100 2005/03/25 00:34:28 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 /* Some old versions of Kerberos do not include <com_err.h> in <krb5.h> */
 247 #if !defined(__COM_ERR_H) && !defined(__COM_ERR_H__)
 248 #include <com_err.h>
 249 #endif
 250
 251 /*
 252  * pg_an_to_ln -- return the local name corresponding to an authentication
 253  *                                name
 254  *
 255  * XXX Assumes that the first aname component is the user name.  This is NOT
 256  *         necessarily so, since an aname can actually be something out of your
 257  *         worst X.400 nightmare, like
 258  *                ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
 259  *         Note that the MIT an_to_ln code does the same thing if you don't
 260  *         provide an aname mapping database...it may be a better idea to use
 261  *         krb5_an_to_ln, except that it punts if multiple components are found,
 262  *         and we can't afford to punt.
 263  */
 264 static char *
 265 pg_an_to_ln(char *aname)
 266 {
 267         char       *p;
 268
 269         if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
 270                 *p = '\0';
 271         return aname;
 272 }
 273
 274
 275 /*
 276  * Various krb5 state which is not connection specific, and a flag to
 277  * indicate whether we have initialised it yet.
 278  */
 279 static int      pg_krb5_initialised;
 280 static krb5_context pg_krb5_context;
 281 static krb5_ccache pg_krb5_ccache;
 282 static krb5_principal pg_krb5_client;
 283 static char *pg_krb5_name;
 284
 285
 286 static int
 287 pg_krb5_init(char *PQerrormsg)
 288 {
 289         krb5_error_code retval;
 290
 291         if (pg_krb5_initialised)
 292                 return STATUS_OK;
 293
 294         retval = krb5_init_context(&pg_krb5_context);
 295         if (retval)
 296         {
 297                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 298                                  "pg_krb5_init: krb5_init_context: %s\n",
 299                                  error_message(retval));
 300                 return STATUS_ERROR;
 301         }
 302
 303         retval = krb5_cc_default(pg_krb5_context, &pg_krb5_ccache);
 304         if (retval)
 305         {
 306                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 307                                  "pg_krb5_init: krb5_cc_default: %s\n",
 308                                  error_message(retval));
 309                 krb5_free_context(pg_krb5_context);
 310                 return STATUS_ERROR;
 311         }
 312
 313         retval = krb5_cc_get_principal(pg_krb5_context, pg_krb5_ccache,
 314                                                                    &pg_krb5_client);
 315         if (retval)
 316         {
 317                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 318                                  "pg_krb5_init: krb5_cc_get_principal: %s\n",
 319                                  error_message(retval));
 320                 krb5_cc_close(pg_krb5_context, pg_krb5_ccache);
 321                 krb5_free_context(pg_krb5_context);
 322                 return STATUS_ERROR;
 323         }
 324
 325         retval = krb5_unparse_name(pg_krb5_context, pg_krb5_client, &pg_krb5_name);
 326         if (retval)
 327         {
 328                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 329                                  "pg_krb5_init: krb5_unparse_name: %s\n",
 330                                  error_message(retval));
 331                 krb5_free_principal(pg_krb5_context, pg_krb5_client);
 332                 krb5_cc_close(pg_krb5_context, pg_krb5_ccache);
 333                 krb5_free_context(pg_krb5_context);
 334                 return STATUS_ERROR;
 335         }
 336
 337         pg_krb5_name = pg_an_to_ln(pg_krb5_name);
 338
 339         pg_krb5_initialised = 1;
 340         return STATUS_OK;
 341 }
 342
 343
 344 /*
 345  * pg_krb5_authname -- returns a pointer to static space containing whatever
 346  *                                         name the user has authenticated to the system
 347   */
 348 static const char *
 349 pg_krb5_authname(char *PQerrormsg)
 350 {
 351         if (pg_krb5_init(PQerrormsg) != STATUS_OK)
 352                 return NULL;
 353
 354         return pg_krb5_name;
 355 }
 356
 357
 358 /*
 359  * pg_krb5_sendauth -- client routine to send authentication information to
 360  *                                         the server
 361  */
 362 static int
 363 pg_krb5_sendauth(char *PQerrormsg, int sock, const char *hostname)
 364 {
 365         krb5_error_code retval;
 366         int                     ret;
 367         krb5_principal server;
 368         krb5_auth_context auth_context = NULL;
 369         krb5_error *err_ret = NULL;
 370
 371         if (!hostname)
 372         {
 373                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 374                                  "pg_krb5_sendauth: hostname must be specified for Kerberos authentication\n");
 375                 return STATUS_ERROR;
 376         }
 377
 378         ret = pg_krb5_init(PQerrormsg);
 379         if (ret != STATUS_OK)
 380                 return ret;
 381
 382         retval = krb5_sname_to_principal(pg_krb5_context, hostname, PG_KRB_SRVNAM,
 383                                                                          KRB5_NT_SRV_HST, &server);
 384         if (retval)
 385         {
 386                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 387                                  "pg_krb5_sendauth: krb5_sname_to_principal: %s\n",
 388                                  error_message(retval));
 389                 return STATUS_ERROR;
 390         }
 391
 392         /*
 393          * libpq uses a non-blocking socket. But kerberos needs a blocking
 394          * socket, and we have to block somehow to do mutual authentication
 395          * anyway. So we temporarily make it blocking.
 396          */
 397         if (!pg_set_block(sock))
 398         {
 399                 char            sebuf[256];
 400
 401                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 402                                  libpq_gettext("could not set socket to blocking mode: %s\n"), pqStrerror(errno, sebuf, sizeof(sebuf)));
 403                 krb5_free_principal(pg_krb5_context, server);
 404                 return STATUS_ERROR;
 405         }
 406
 407         retval = krb5_sendauth(pg_krb5_context, &auth_context,
 408                                                    (krb5_pointer) & sock, PG_KRB_SRVNAM,
 409                                                    pg_krb5_client, server,
 410                                                    AP_OPTS_MUTUAL_REQUIRED,
 411                                                    NULL, 0,             /* no creds, use ccache instead */
 412                                                    pg_krb5_ccache, &err_ret, NULL, NULL);
 413         if (retval)
 414         {
 415                 if (retval == KRB5_SENDAUTH_REJECTED && err_ret)
 416                 {
 417 #if defined(HAVE_KRB5_ERROR_TEXT_DATA)
 418                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 419                           libpq_gettext("Kerberos 5 authentication rejected: %*s\n"),
 420                                          (int) err_ret->text.length, err_ret->text.data);
 421 #elif defined(HAVE_KRB5_ERROR_E_DATA)
 422                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 423                           libpq_gettext("Kerberos 5 authentication rejected: %*s\n"),
 424                                          (int) err_ret->e_data->length,
 425                                          (const char *) err_ret->e_data->data);
 426 #else
 427 #error "bogus configuration"
 428 #endif
 429                 }
 430                 else
 431                 {
 432                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 433                                          "krb5_sendauth: %s\n", error_message(retval));
 434                 }
 435
 436                 if (err_ret)
 437                         krb5_free_error(pg_krb5_context, err_ret);
 438
 439                 ret = STATUS_ERROR;
 440         }
 441
 442         krb5_free_principal(pg_krb5_context, server);
 443
 444         if (!pg_set_noblock(sock))
 445         {
 446                 char            sebuf[256];
 447
 448                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 449                                  libpq_gettext("could not restore non-blocking mode on socket: %s\n"),
 450                                  pqStrerror(errno, sebuf, sizeof(sebuf)));
 451                 ret = STATUS_ERROR;
 452         }
 453
 454         return ret;
 455 }
 456 #endif   /* KRB5 */
 457
 458 /*
 459  * Respond to AUTH_REQ_SCM_CREDS challenge.
 460  *
 461  * Note: current backends will not use this challenge if HAVE_GETPEEREID
 462  * or SO_PEERCRED is defined, but pre-7.4 backends might, so compile the
 463  * code anyway.
 464  */
 465 static int
 466 pg_local_sendauth(char *PQerrormsg, PGconn *conn)
 467 {
 468 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || \
 469         (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS))
 470         char            buf;
 471         struct iovec iov;
 472         struct msghdr msg;
 473
 474 #ifdef HAVE_STRUCT_CMSGCRED
 475         /* Prevent padding */
 476         char            cmsgmem[sizeof(struct cmsghdr) + sizeof(struct cmsgcred)];
 477
 478         /* Point to start of first structure */
 479         struct cmsghdr *cmsg = (struct cmsghdr *) cmsgmem;
 480 #endif
 481
 482         /*
 483          * The backend doesn't care what we send here, but it wants exactly
 484          * one character to force recvmsg() to block and wait for us.
 485          */
 486         buf = '\0';
 487         iov.iov_base = &buf;
 488         iov.iov_len = 1;
 489
 490         memset(&msg, 0, sizeof(msg));
 491         msg.msg_iov = &iov;
 492         msg.msg_iovlen = 1;
 493
 494 #ifdef HAVE_STRUCT_CMSGCRED
 495         /* Create control header, FreeBSD */
 496         msg.msg_control = cmsg;
 497         msg.msg_controllen = sizeof(cmsgmem);
 498         memset(cmsg, 0, sizeof(cmsgmem));
 499         cmsg->cmsg_len = sizeof(cmsgmem);
 500         cmsg->cmsg_level = SOL_SOCKET;
 501         cmsg->cmsg_type = SCM_CREDS;
 502 #endif
 503
 504         if (sendmsg(conn->sock, &msg, 0) == -1)
 505         {
 506                 char            sebuf[256];
 507
 508                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 509                                  "pg_local_sendauth: sendmsg: %s\n",
 510                                  pqStrerror(errno, sebuf, sizeof(sebuf)));
 511                 return STATUS_ERROR;
 512         }
 513         return STATUS_OK;
 514 #else
 515         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 516                 libpq_gettext("SCM_CRED authentication method not supported\n"));
 517         return STATUS_ERROR;
 518 #endif
 519 }
 520
 521 static int
 522 pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
 523 {
 524         int                     ret;
 525         char       *crypt_pwd;
 526
 527         /* Encrypt the password if needed. */
 528
 529         switch (areq)
 530         {
 531                 case AUTH_REQ_MD5:
 532                         {
 533                                 char       *crypt_pwd2;
 534
 535                                 if (!(crypt_pwd = malloc(MD5_PASSWD_LEN + 1)) ||
 536                                         !(crypt_pwd2 = malloc(MD5_PASSWD_LEN + 1)))
 537                                 {
 538                                         fprintf(stderr, libpq_gettext("out of memory\n"));
 539                                         return STATUS_ERROR;
 540                                 }
 541                                 if (!EncryptMD5(password, conn->pguser,
 542                                                                 strlen(conn->pguser), crypt_pwd2))
 543                                 {
 544                                         free(crypt_pwd);
 545                                         free(crypt_pwd2);
 546                                         return STATUS_ERROR;
 547                                 }
 548                                 if (!EncryptMD5(crypt_pwd2 + strlen("md5"), conn->md5Salt,
 549                                                                 sizeof(conn->md5Salt), crypt_pwd))
 550                                 {
 551                                         free(crypt_pwd);
 552                                         free(crypt_pwd2);
 553                                         return STATUS_ERROR;
 554                                 }
 555                                 free(crypt_pwd2);
 556                                 break;
 557                         }
 558                 case AUTH_REQ_CRYPT:
 559                         {
 560                                 char            salt[3];
 561
 562                                 StrNCpy(salt, conn->cryptSalt, 3);
 563                                 crypt_pwd = crypt(password, salt);
 564                                 break;
 565                         }
 566                 case AUTH_REQ_PASSWORD:
 567                         /* discard const so we can assign it */
 568                         crypt_pwd = (char *) password;
 569                         break;
 570                 default:
 571                         return STATUS_ERROR;
 572         }
 573         /* Packet has a message type as of protocol 3.0 */
 574         if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3)
 575                 ret = pqPacketSend(conn, 'p', crypt_pwd, strlen(crypt_pwd) + 1);
 576         else
 577                 ret = pqPacketSend(conn, 0, crypt_pwd, strlen(crypt_pwd) + 1);
 578         if (areq == AUTH_REQ_MD5)
 579                 free(crypt_pwd);
 580         return ret;
 581 }
 582
 583 /*
 584  * fe_sendauth -- client demux routine for outgoing authentication information
 585  */
 586 int
 587 fe_sendauth(AuthRequest areq, PGconn *conn, const char *hostname,
 588                         const char *password, char *PQerrormsg)
 589 {
 590 #if !defined(KRB4) && !defined(KRB5)
 591         (void) hostname;                        /* not used */
 592 #endif
 593
 594         switch (areq)
 595         {
 596                 case AUTH_REQ_OK:
 597                         break;
 598
 599                 case AUTH_REQ_KRB4:
 600 #ifdef KRB4
 601                         pglock_thread();
 602                         if (pg_krb4_sendauth(PQerrormsg, conn->sock,
 603                                                            (struct sockaddr_in *) & conn->laddr.addr,
 604                                                            (struct sockaddr_in *) & conn->raddr.addr,
 605                                                                  hostname) != STATUS_OK)
 606                         {
 607                                 /* PQerrormsg already filled in */
 608                                 pgunlock_thread();
 609                                 return STATUS_ERROR;
 610                         }
 611                         pgunlock_thread();
 612                         break;
 613 #else
 614                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 615                          libpq_gettext("Kerberos 4 authentication not supported\n"));
 616                         return STATUS_ERROR;
 617 #endif
 618
 619                 case AUTH_REQ_KRB5:
 620 #ifdef KRB5
 621                         pglock_thread();
 622                         if (pg_krb5_sendauth(PQerrormsg, conn->sock,
 623                                                                  hostname) != STATUS_OK)
 624                         {
 625                                 /* PQerrormsg already filled in */
 626                                 pgunlock_thread();
 627                                 return STATUS_ERROR;
 628                         }
 629                         pgunlock_thread();
 630                         break;
 631 #else
 632                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 633                          libpq_gettext("Kerberos 5 authentication not supported\n"));
 634                         return STATUS_ERROR;
 635 #endif
 636
 637                 case AUTH_REQ_MD5:
 638                 case AUTH_REQ_CRYPT:
 639                 case AUTH_REQ_PASSWORD:
 640                         if (password == NULL || *password == '\0')
 641                         {
 642                                 (void) snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 643                                                                 PQnoPasswordSupplied);
 644                                 return STATUS_ERROR;
 645                         }
 646                         if (pg_password_sendauth(conn, password, areq) != STATUS_OK)
 647                         {
 648                                 (void) snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 649                                  "fe_sendauth: error sending password authentication\n");
 650                                 return STATUS_ERROR;
 651                         }
 652                         break;
 653
 654                 case AUTH_REQ_SCM_CREDS:
 655                         if (pg_local_sendauth(PQerrormsg, conn) != STATUS_OK)
 656                                 return STATUS_ERROR;
 657                         break;
 658
 659                 default:
 660                         snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 661                                          libpq_gettext("authentication method %u not supported\n"), areq);
 662                         return STATUS_ERROR;
 663         }
 664
 665         return STATUS_OK;
 666 }
 667
 668 /*
 669  * fe_setauthsvc
 670  * fe_getauthsvc
 671  *
 672  * Set/return the authentication service currently selected for use by the
 673  * frontend. (You can only use one in the frontend, obviously.)
 674  *
 675  * NB: This is not thread-safe if different threads try to select different
 676  * authentication services!  It's OK for fe_getauthsvc to select the default,
 677  * since that will be the same for all threads, but direct application use
 678  * of fe_setauthsvc is not thread-safe.  However, use of fe_setauthsvc is
 679  * deprecated anyway...
 680  */
 681
 682 static int      pg_authsvc = -1;
 683
 684 void
 685 fe_setauthsvc(const char *name, char *PQerrormsg)
 686 {
 687         int                     i;
 688
 689         for (i = 0; i < n_authsvcs; ++i)
 690                 if (strcmp(name, authsvcs[i].name) == 0)
 691                 {
 692                         pg_authsvc = i;
 693                         break;
 694                 }
 695         if (i == n_authsvcs)
 696         {
 697                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 698                                  libpq_gettext("invalid authentication service name \"%s\", ignored\n"),
 699                                  name);
 700         }
 701         return;
 702 }
 703
 704 MsgType
 705 fe_getauthsvc(char *PQerrormsg)
 706 {
 707         if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
 708         {
 709                 fe_setauthsvc(DEFAULT_CLIENT_AUTHSVC, PQerrormsg);
 710                 if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
 711                 {
 712                         /* Can only get here if DEFAULT_CLIENT_AUTHSVC is misdefined */
 713                         return 0;
 714                 }
 715         }
 716         return authsvcs[pg_authsvc].msgtype;
 717 }
 718
 719 /*
 720  * fe_getauthname -- returns a pointer to dynamic space containing whatever
 721  *                                       name the user has authenticated to the system
 722  * if there is an error, return the error message in PQerrormsg
 723  */
 724 char *
 725 fe_getauthname(char *PQerrormsg)
 726 {
 727         const char *name = NULL;
 728         char       *authn;
 729         MsgType         authsvc;
 730 #ifdef WIN32
 731         char            username[128];
 732         DWORD           namesize = sizeof(username) - 1;
 733 #else
 734         char            pwdbuf[BUFSIZ];
 735         struct passwd pwdstr;
 736         struct passwd *pw = NULL;
 737 #endif
 738
 739         authsvc = fe_getauthsvc(PQerrormsg);
 740
 741         /* this just guards against broken DEFAULT_CLIENT_AUTHSVC, see above */
 742         if (authsvc == 0)
 743                 return NULL;                    /* leave original error message in place */
 744
 745         pglock_thread();
 746
 747 #ifdef KRB4
 748         if (authsvc == STARTUP_KRB4_MSG)
 749                 name = pg_krb4_authname(PQerrormsg);
 750 #endif
 751 #ifdef KRB5
 752         if (authsvc == STARTUP_KRB5_MSG)
 753                 name = pg_krb5_authname(PQerrormsg);
 754 #endif
 755
 756         if (authsvc == STARTUP_MSG
 757                 || (authsvc == STARTUP_KRB4_MSG && !name)
 758                 || (authsvc == STARTUP_KRB5_MSG && !name))
 759         {
 760 #ifdef WIN32
 761                 if (GetUserName(username, &namesize))
 762                         name = username;
 763 #else
 764                 if (pqGetpwuid(geteuid(), &pwdstr, pwdbuf, sizeof(pwdbuf), &pw) == 0)
 765                         name = pw->pw_name;
 766 #endif
 767         }
 768
 769         if (authsvc != STARTUP_MSG && authsvc != STARTUP_KRB4_MSG && authsvc != STARTUP_KRB5_MSG)
 770                 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
 771                                  libpq_gettext("fe_getauthname: invalid authentication system: %d\n"),
 772                                  authsvc);
 773
 774         authn = name ? strdup(name) : NULL;
 775
 776         pgunlock_thread();
 777
 778         return authn;
 779 }