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

   1 /*-------------------------------------------------------------------------
   2  *
   3  * auth.c
   4  *        Routines to handle network authentication
   5  *
   6  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $Header: /cvsroot/pgsql/src/backend/libpq/auth.c,v 1.98 2003/04/17 22:26:01 tgl Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15
  16 #include "postgres.h"
  17
  18 #include <sys/param.h>
  19 #include <sys/socket.h>
  20 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
  21 #include <sys/uio.h>
  22 #include <sys/ucred.h>
  23 #include <errno.h>
  24 #endif
  25 #include <netinet/in.h>
  26 #include <arpa/inet.h>
  27
  28 #include "libpq/auth.h"
  29 #include "libpq/crypt.h"
  30 #include "libpq/hba.h"
  31 #include "libpq/libpq.h"
  32 #include "libpq/pqcomm.h"
  33 #include "libpq/pqformat.h"
  34 #include "miscadmin.h"
  35 #include "storage/ipc.h"
  36
  37
  38 static void sendAuthRequest(Port *port, AuthRequest areq);
  39 static void auth_failed(Port *port, int status);
  40 static int      recv_and_check_password_packet(Port *port);
  41
  42 char       *pg_krb_server_keyfile;
  43
  44 #ifdef USE_PAM
  45 #ifdef HAVE_PAM_PAM_APPL_H
  46 #include <pam/pam_appl.h>
  47 #endif
  48 #ifdef HAVE_SECURITY_PAM_APPL_H
  49 #include <security/pam_appl.h>
  50 #endif
  51
  52 #define PGSQL_PAM_SERVICE "postgresql"  /* Service name passed to PAM */
  53
  54 static int      CheckPAMAuth(Port *port, char *user, char *password);
  55 static int pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg,
  56                                          struct pam_response ** resp, void *appdata_ptr);
  57
  58 static struct pam_conv pam_passw_conv = {
  59         &pam_passwd_conv_proc,
  60         NULL
  61 };
  62
  63 static char *pam_passwd = NULL; /* Workaround for Solaris 2.6 brokenness */
  64 static Port *pam_port_cludge;   /* Workaround for passing "Port *port"
  65                                                                  * into pam_passwd_conv_proc */
  66 #endif   /* USE_PAM */
  67
  68 #ifdef KRB4
  69 /*----------------------------------------------------------------
  70  * MIT Kerberos authentication system - protocol version 4
  71  *----------------------------------------------------------------
  72  */
  73
  74 #include "krb.h"
  75
  76 /*
  77  * pg_krb4_recvauth -- server routine to receive authentication information
  78  *                                         from the client
  79  *
  80  * Nothing unusual here, except that we compare the username obtained from
  81  * the client's setup packet to the authenticated name.  (We have to retain
  82  * the name in the setup packet since we have to retain the ability to handle
  83  * unauthenticated connections.)
  84  */
  85 static int
  86 pg_krb4_recvauth(Port *port)
  87 {
  88         long            krbopts = 0;    /* one-way authentication */
  89         KTEXT_ST        clttkt;
  90         char            instance[INST_SZ + 1],
  91                                 version[KRB_SENDAUTH_VLEN + 1];
  92         AUTH_DAT        auth_data;
  93         Key_schedule key_sched;
  94         int                     status;
  95
  96         strcpy(instance, "*");          /* don't care, but arg gets expanded
  97                                                                  * anyway */
  98         status = krb_recvauth(krbopts,
  99                                                   port->sock,
 100                                                   &clttkt,
 101                                                   PG_KRB_SRVNAM,
 102                                                   instance,
 103                                                   &port->raddr.in,
 104                                                   &port->laddr.in,
 105                                                   &auth_data,
 106                                                   pg_krb_server_keyfile,
 107                                                   key_sched,
 108                                                   version);
 109         if (status != KSUCCESS)
 110         {
 111                 elog(LOG, "pg_krb4_recvauth: kerberos error: %s",
 112                          krb_err_txt[status]);
 113                 return STATUS_ERROR;
 114         }
 115         if (strncmp(version, PG_KRB4_VERSION, KRB_SENDAUTH_VLEN) != 0)
 116         {
 117                 elog(LOG, "pg_krb4_recvauth: protocol version \"%s\" != \"%s\"",
 118                          version, PG_KRB4_VERSION);
 119                 return STATUS_ERROR;
 120         }
 121         if (strncmp(port->user, auth_data.pname, SM_DATABASE_USER) != 0)
 122         {
 123                 elog(LOG, "pg_krb4_recvauth: name \"%s\" != \"%s\"",
 124                          port->user, auth_data.pname);
 125                 return STATUS_ERROR;
 126         }
 127         return STATUS_OK;
 128 }
 129
 130 #else
 131
 132 static int
 133 pg_krb4_recvauth(Port *port)
 134 {
 135         elog(LOG, "pg_krb4_recvauth: Kerberos not implemented on this server");
 136         return STATUS_ERROR;
 137 }
 138 #endif   /* KRB4 */
 139
 140
 141 #ifdef KRB5
 142 /*----------------------------------------------------------------
 143  * MIT Kerberos authentication system - protocol version 5
 144  *----------------------------------------------------------------
 145  */
 146
 147 #include <krb5.h>
 148 #include <com_err.h>
 149
 150 /*
 151  * pg_an_to_ln -- return the local name corresponding to an authentication
 152  *                                name
 153  *
 154  * XXX Assumes that the first aname component is the user name.  This is NOT
 155  *         necessarily so, since an aname can actually be something out of your
 156  *         worst X.400 nightmare, like
 157  *                ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
 158  *         Note that the MIT an_to_ln code does the same thing if you don't
 159  *         provide an aname mapping database...it may be a better idea to use
 160  *         krb5_an_to_ln, except that it punts if multiple components are found,
 161  *         and we can't afford to punt.
 162  */
 163 static char *
 164 pg_an_to_ln(char *aname)
 165 {
 166         char       *p;
 167
 168         if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
 169                 *p = '\0';
 170         return aname;
 171 }
 172
 173
 174 /*
 175  * Various krb5 state which is not connection specfic, and a flag to
 176  * indicate whether we have initialised it yet.
 177  */
 178 static int      pg_krb5_initialised;
 179 static krb5_context pg_krb5_context;
 180 static krb5_keytab pg_krb5_keytab;
 181 static krb5_principal pg_krb5_server;
 182
 183
 184 static int
 185 pg_krb5_init(void)
 186 {
 187         krb5_error_code retval;
 188
 189         if (pg_krb5_initialised)
 190                 return STATUS_OK;
 191
 192         retval = krb5_init_context(&pg_krb5_context);
 193         if (retval)
 194         {
 195                 elog(LOG, "pg_krb5_init: krb5_init_context returned Kerberos error %d",
 196                          retval);
 197                 com_err("postgres", retval, "while initializing krb5");
 198                 return STATUS_ERROR;
 199         }
 200
 201         retval = krb5_kt_resolve(pg_krb5_context, pg_krb_server_keyfile, &pg_krb5_keytab);
 202         if (retval)
 203         {
 204                 elog(LOG, "pg_krb5_init: krb5_kt_resolve returned Kerberos error %d",
 205                          retval);
 206                 com_err("postgres", retval, "while resolving keytab file %s",
 207                                 pg_krb_server_keyfile);
 208                 krb5_free_context(pg_krb5_context);
 209                 return STATUS_ERROR;
 210         }
 211
 212         retval = krb5_sname_to_principal(pg_krb5_context, NULL, PG_KRB_SRVNAM,
 213                                                                          KRB5_NT_SRV_HST, &pg_krb5_server);
 214         if (retval)
 215         {
 216                 elog(LOG, "pg_krb5_init: krb5_sname_to_principal returned Kerberos error %d",
 217                          retval);
 218                 com_err("postgres", retval,
 219                                 "while getting server principal for service %s",
 220                                 PG_KRB_SRVNAM);
 221                 krb5_kt_close(pg_krb5_context, pg_krb5_keytab);
 222                 krb5_free_context(pg_krb5_context);
 223                 return STATUS_ERROR;
 224         }
 225
 226         pg_krb5_initialised = 1;
 227         return STATUS_OK;
 228 }
 229
 230
 231 /*
 232  * pg_krb5_recvauth -- server routine to receive authentication information
 233  *                                         from the client
 234  *
 235  * We still need to compare the username obtained from the client's setup
 236  * packet to the authenticated name, as described in pg_krb4_recvauth.  This
 237  * is a bit more problematic in v5, as described above in pg_an_to_ln.
 238  *
 239  * We have our own keytab file because postgres is unlikely to run as root,
 240  * and so cannot read the default keytab.
 241  */
 242 static int
 243 pg_krb5_recvauth(Port *port)
 244 {
 245         krb5_error_code retval;
 246         int                     ret;
 247         krb5_auth_context auth_context = NULL;
 248         krb5_ticket *ticket;
 249         char       *kusername;
 250
 251         ret = pg_krb5_init();
 252         if (ret != STATUS_OK)
 253                 return ret;
 254
 255         retval = krb5_recvauth(pg_krb5_context, &auth_context,
 256                                                    (krb5_pointer) & port->sock, PG_KRB_SRVNAM,
 257                                                    pg_krb5_server, 0, pg_krb5_keytab, &ticket);
 258         if (retval)
 259         {
 260                 elog(LOG, "pg_krb5_recvauth: krb5_recvauth returned Kerberos error %d",
 261                          retval);
 262                 com_err("postgres", retval, "from krb5_recvauth");
 263                 return STATUS_ERROR;
 264         }
 265
 266         /*
 267          * The "client" structure comes out of the ticket and is therefore
 268          * authenticated.  Use it to check the username obtained from the
 269          * postmaster startup packet.
 270          *
 271          * I have no idea why this is considered necessary.
 272          */
 273 #if defined(HAVE_KRB5_TICKET_ENC_PART2)
 274         retval = krb5_unparse_name(pg_krb5_context,
 275                                                            ticket->enc_part2->client, &kusername);
 276 #elif defined(HAVE_KRB5_TICKET_CLIENT)
 277         retval = krb5_unparse_name(pg_krb5_context,
 278                                                            ticket->client, &kusername);
 279 #else
 280 #error "bogus configuration"
 281 #endif
 282         if (retval)
 283         {
 284                 elog(LOG, "pg_krb5_recvauth: krb5_unparse_name returned Kerberos error %d",
 285                          retval);
 286                 com_err("postgres", retval, "while unparsing client name");
 287                 krb5_free_ticket(pg_krb5_context, ticket);
 288                 krb5_auth_con_free(pg_krb5_context, auth_context);
 289                 return STATUS_ERROR;
 290         }
 291
 292         kusername = pg_an_to_ln(kusername);
 293         if (strncmp(port->user, kusername, SM_DATABASE_USER))
 294         {
 295                 elog(LOG, "pg_krb5_recvauth: user name \"%s\" != krb5 name \"%s\"",
 296                          port->user, kusername);
 297                 ret = STATUS_ERROR;
 298         }
 299         else
 300                 ret = STATUS_OK;
 301
 302         krb5_free_ticket(pg_krb5_context, ticket);
 303         krb5_auth_con_free(pg_krb5_context, auth_context);
 304         free(kusername);
 305
 306         return ret;
 307 }
 308
 309 #else
 310
 311 static int
 312 pg_krb5_recvauth(Port *port)
 313 {
 314         elog(LOG, "pg_krb5_recvauth: Kerberos not implemented on this server");
 315         return STATUS_ERROR;
 316 }
 317 #endif   /* KRB5 */
 318
 319
 320 /*
 321  * Tell the user the authentication failed, but not (much about) why.
 322  *
 323  * There is a tradeoff here between security concerns and making life
 324  * unnecessarily difficult for legitimate users.  We would not, for example,
 325  * want to report the password we were expecting to receive...
 326  * But it seems useful to report the username and authorization method
 327  * in use, and these are items that must be presumed known to an attacker
 328  * anyway.
 329  * Note that many sorts of failure report additional information in the
 330  * postmaster log, which we hope is only readable by good guys.
 331  */
 332 static void
 333 auth_failed(Port *port, int status)
 334 {
 335         const char *authmethod = "Unknown auth method:";
 336
 337         /*
 338          * If we failed due to EOF from client, just quit; there's no point in
 339          * trying to send a message to the client, and not much point in
 340          * logging the failure in the postmaster log.  (Logging the failure
 341          * might be desirable, were it not for the fact that libpq closes the
 342          * connection unceremoniously if challenged for a password when it
 343          * hasn't got one to send.  We'll get a useless log entry for every
 344          * psql connection under password auth, even if it's perfectly
 345          * successful, if we log STATUS_EOF events.)
 346          */
 347         if (status == STATUS_EOF)
 348                 proc_exit(0);
 349
 350         switch (port->auth_method)
 351         {
 352                 case uaReject:
 353                         authmethod = "Rejected host:";
 354                         break;
 355                 case uaKrb4:
 356                         authmethod = "Kerberos4";
 357                         break;
 358                 case uaKrb5:
 359                         authmethod = "Kerberos5";
 360                         break;
 361                 case uaTrust:
 362                         authmethod = "Trusted";
 363                         break;
 364                 case uaIdent:
 365                         authmethod = "IDENT";
 366                         break;
 367                 case uaMD5:
 368                 case uaCrypt:
 369                 case uaPassword:
 370                         authmethod = "Password";
 371                         break;
 372 #ifdef USE_PAM
 373                 case uaPAM:
 374                         authmethod = "PAM";
 375                         break;
 376 #endif   /* USE_PAM */
 377         }
 378
 379         elog(FATAL, "%s authentication failed for user \"%s\"",
 380                  authmethod, port->user_name);
 381         /* doesn't return */
 382 }
 383
 384
 385 /*
 386  * Client authentication starts here.  If there is an error, this
 387  * function does not return and the backend process is terminated.
 388  */
 389 void
 390 ClientAuthentication(Port *port)
 391 {
 392         int                     status = STATUS_ERROR;
 393
 394         /*
 395          * Get the authentication method to use for this frontend/database
 396          * combination.  Note: a failure return indicates a problem with the
 397          * hba config file, not with the request.  hba.c should have dropped
 398          * an error message into the postmaster logfile if it failed.
 399          */
 400         if (hba_getauthmethod(port) != STATUS_OK)
 401                 elog(FATAL, "Missing or erroneous pg_hba.conf file, see postmaster log for details");
 402
 403         switch (port->auth_method)
 404         {
 405                 case uaReject:
 406
 407                         /*
 408                          * This could have come from an explicit "reject" entry in
 409                          * pg_hba.conf, but more likely it means there was no matching
 410                          * entry.  Take pity on the poor user and issue a helpful
 411                          * error message.  NOTE: this is not a security breach,
 412                          * because all the info reported here is known at the frontend
 413                          * and must be assumed known to bad guys. We're merely helping
 414                          * out the less clueful good guys.
 415                          */
 416                         {
 417                                 const char *hostinfo = "localhost";
 418 #ifdef HAVE_IPV6
 419                                 char    ip_hostinfo[INET6_ADDRSTRLEN];
 420 #else
 421                                 char    ip_hostinfo[INET_ADDRSTRLEN];
 422 #endif
 423                                 if (isAF_INETx(port->raddr.sa.sa_family) )
 424                                         hostinfo = SockAddr_ntop(&port->raddr, ip_hostinfo,
 425                                                            sizeof(ip_hostinfo), 1);
 426
 427                                 elog(FATAL,
 428                                         "No pg_hba.conf entry for host %s, user %s, database %s",
 429                                         hostinfo, port->user_name, port->database_name);
 430                                 break;
 431                         }
 432
 433                 case uaKrb4:
 434                         sendAuthRequest(port, AUTH_REQ_KRB4);
 435                         status = pg_krb4_recvauth(port);
 436                         break;
 437
 438                 case uaKrb5:
 439                         sendAuthRequest(port, AUTH_REQ_KRB5);
 440                         status = pg_krb5_recvauth(port);
 441                         break;
 442
 443                 case uaIdent:
 444 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || \
 445         (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS)) && \
 446         !defined(HAVE_GETPEEREID) && !defined(SO_PEERCRED)
 447
 448                         /*
 449                          * If we are doing ident on unix-domain sockets, use SCM_CREDS
 450                          * only if it is defined and SO_PEERCRED isn't.
 451                          */
 452 #if defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
 453
 454                         /*
 455                          * Receive credentials on next message receipt, BSD/OS,
 456                          * NetBSD. We need to set this before the client sends the
 457                          * next packet.
 458                          */
 459                         {
 460                                 int                     on = 1;
 461
 462                                 if (setsockopt(port->sock, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
 463                                         elog(FATAL, "pg_local_sendauth: can't do setsockopt: %m");
 464                         }
 465 #endif
 466                         if (port->raddr.sa.sa_family == AF_UNIX)
 467                                 sendAuthRequest(port, AUTH_REQ_SCM_CREDS);
 468 #endif
 469                         status = authident(port);
 470                         break;
 471
 472                 case uaMD5:
 473                         sendAuthRequest(port, AUTH_REQ_MD5);
 474                         status = recv_and_check_password_packet(port);
 475                         break;
 476
 477                 case uaCrypt:
 478                         sendAuthRequest(port, AUTH_REQ_CRYPT);
 479                         status = recv_and_check_password_packet(port);
 480                         break;
 481
 482                 case uaPassword:
 483                         sendAuthRequest(port, AUTH_REQ_PASSWORD);
 484                         status = recv_and_check_password_packet(port);
 485                         break;
 486
 487 #ifdef USE_PAM
 488                 case uaPAM:
 489                         pam_port_cludge = port;
 490                         status = CheckPAMAuth(port, port->user, "");
 491                         break;
 492 #endif   /* USE_PAM */
 493
 494                 case uaTrust:
 495                         status = STATUS_OK;
 496                         break;
 497         }
 498
 499         if (status == STATUS_OK)
 500                 sendAuthRequest(port, AUTH_REQ_OK);
 501         else
 502                 auth_failed(port, status);
 503 }
 504
 505
 506 /*
 507  * Send an authentication request packet to the frontend.
 508  */
 509 static void
 510 sendAuthRequest(Port *port, AuthRequest areq)
 511 {
 512         StringInfoData buf;
 513
 514         pq_beginmessage(&buf);
 515         pq_sendbyte(&buf, 'R');
 516         pq_sendint(&buf, (int32) areq, sizeof(int32));
 517
 518         /* Add the salt for encrypted passwords. */
 519         if (areq == AUTH_REQ_MD5)
 520                 pq_sendbytes(&buf, port->md5Salt, 4);
 521         else if (areq == AUTH_REQ_CRYPT)
 522                 pq_sendbytes(&buf, port->cryptSalt, 2);
 523
 524         pq_endmessage(&buf);
 525
 526         /*
 527          * Flush message so client will see it, except for AUTH_REQ_OK, which
 528          * need not be sent until we are ready for queries.
 529          */
 530         if (areq != AUTH_REQ_OK)
 531                 pq_flush();
 532 }
 533
 534
 535 #ifdef USE_PAM
 536
 537 /*
 538  * PAM conversation function
 539  */
 540
 541 static int
 542 pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg, struct pam_response ** resp, void *appdata_ptr)
 543 {
 544         StringInfoData buf;
 545         int32           len;
 546
 547         if (num_msg != 1 || msg[0]->msg_style != PAM_PROMPT_ECHO_OFF)
 548         {
 549                 switch (msg[0]->msg_style)
 550                 {
 551                         case PAM_ERROR_MSG:
 552                                 elog(LOG, "pam_passwd_conv_proc: Error from underlying PAM layer: '%s'",
 553                                          msg[0]->msg);
 554                                 return PAM_CONV_ERR;
 555                         default:
 556                                 elog(LOG, "pam_passwd_conv_proc: Unexpected PAM conversation %d/'%s'",
 557                                          msg[0]->msg_style, msg[0]->msg);
 558                                 return PAM_CONV_ERR;
 559                 }
 560         }
 561
 562         if (!appdata_ptr)
 563         {
 564                 /*
 565                  * Workaround for Solaris 2.6 where the PAM library is broken and
 566                  * does not pass appdata_ptr to the conversation routine
 567                  */
 568                 appdata_ptr = pam_passwd;
 569         }
 570
 571         /*
 572          * Password wasn't passed to PAM the first time around - let's go ask
 573          * the client to send a password, which we then stuff into PAM.
 574          */
 575         if (strlen(appdata_ptr) == 0)
 576         {
 577                 sendAuthRequest(pam_port_cludge, AUTH_REQ_PASSWORD);
 578                 if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
 579                         return PAM_CONV_ERR;    /* client didn't want to send password */
 580
 581                 initStringInfo(&buf);
 582                 if (pq_getstr_bounded(&buf, 1000) == EOF)
 583                         return PAM_CONV_ERR;    /* EOF while reading password */
 584
 585                 /* Do not echo failed password to logs, for security. */
 586                 elog(DEBUG5, "received PAM packet");
 587
 588                 if (strlen(buf.data) == 0)
 589                 {
 590                         elog(LOG, "pam_passwd_conv_proc: no password");
 591                         return PAM_CONV_ERR;
 592                 }
 593                 appdata_ptr = buf.data;
 594         }
 595
 596         /*
 597          * Explicitly not using palloc here - PAM will free this memory in
 598          * pam_end()
 599          */
 600         *resp = calloc(num_msg, sizeof(struct pam_response));
 601         if (!*resp)
 602         {
 603                 elog(LOG, "pam_passwd_conv_proc: Out of memory!");
 604                 if (buf.data)
 605                         pfree(buf.data);
 606                 return PAM_CONV_ERR;
 607         }
 608
 609         (*resp)[0].resp = strdup((char *) appdata_ptr);
 610         (*resp)[0].resp_retcode = 0;
 611
 612         return ((*resp)[0].resp ? PAM_SUCCESS : PAM_CONV_ERR);
 613 }
 614
 615
 616 /*
 617  * Check authentication against PAM.
 618  */
 619 static int
 620 CheckPAMAuth(Port *port, char *user, char *password)
 621 {
 622         int                     retval;
 623         pam_handle_t *pamh = NULL;
 624
 625         /*
 626          * Apparently, Solaris 2.6 is broken, and needs ugly static variable
 627          * workaround
 628          */
 629         pam_passwd = password;
 630
 631         /*
 632          * Set the application data portion of the conversation struct This is
 633          * later used inside the PAM conversation to pass the password to the
 634          * authentication module.
 635          */
 636         pam_passw_conv.appdata_ptr = (char *) password;         /* from password above,
 637                                                                                                                  * not allocated */
 638
 639         /* Optionally, one can set the service name in pg_hba.conf */
 640         if (port->auth_arg && port->auth_arg[0] != '\0')
 641                 retval = pam_start(port->auth_arg, "pgsql@",
 642                                                    &pam_passw_conv, &pamh);
 643         else
 644                 retval = pam_start(PGSQL_PAM_SERVICE, "pgsql@",
 645                                                    &pam_passw_conv, &pamh);
 646
 647         if (retval != PAM_SUCCESS)
 648         {
 649                 elog(LOG, "CheckPAMAuth: Failed to create PAM authenticator: '%s'",
 650                          pam_strerror(pamh, retval));
 651                 pam_passwd = NULL;              /* Unset pam_passwd */
 652                 return STATUS_ERROR;
 653         }
 654
 655         retval = pam_set_item(pamh, PAM_USER, user);
 656
 657         if (retval != PAM_SUCCESS)
 658         {
 659                 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_USER) failed: '%s'",
 660                          pam_strerror(pamh, retval));
 661                 pam_passwd = NULL;              /* Unset pam_passwd */
 662                 return STATUS_ERROR;
 663         }
 664
 665         retval = pam_set_item(pamh, PAM_CONV, &pam_passw_conv);
 666
 667         if (retval != PAM_SUCCESS)
 668         {
 669                 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_CONV) failed: '%s'",
 670                          pam_strerror(pamh, retval));
 671                 pam_passwd = NULL;              /* Unset pam_passwd */
 672                 return STATUS_ERROR;
 673         }
 674
 675         retval = pam_authenticate(pamh, 0);
 676
 677         if (retval != PAM_SUCCESS)
 678         {
 679                 elog(LOG, "CheckPAMAuth: pam_authenticate failed: '%s'",
 680                          pam_strerror(pamh, retval));
 681                 pam_passwd = NULL;              /* Unset pam_passwd */
 682                 return STATUS_ERROR;
 683         }
 684
 685         retval = pam_acct_mgmt(pamh, 0);
 686
 687         if (retval != PAM_SUCCESS)
 688         {
 689                 elog(LOG, "CheckPAMAuth: pam_acct_mgmt failed: '%s'",
 690                          pam_strerror(pamh, retval));
 691                 pam_passwd = NULL;              /* Unset pam_passwd */
 692                 return STATUS_ERROR;
 693         }
 694
 695         retval = pam_end(pamh, retval);
 696
 697         if (retval != PAM_SUCCESS)
 698         {
 699                 elog(LOG, "CheckPAMAuth: Failed to release PAM authenticator: '%s'",
 700                          pam_strerror(pamh, retval));
 701         }
 702
 703         pam_passwd = NULL;                      /* Unset pam_passwd */
 704
 705         return (retval == PAM_SUCCESS ? STATUS_OK : STATUS_ERROR);
 706 }
 707 #endif   /* USE_PAM */
 708
 709
 710 /*
 711  * Called when we have received the password packet.
 712  */
 713 static int
 714 recv_and_check_password_packet(Port *port)
 715 {
 716         StringInfoData buf;
 717         int32           len;
 718         int                     result;
 719
 720         if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
 721                 return STATUS_EOF;              /* client didn't want to send password */
 722
 723         initStringInfo(&buf);
 724         if (pq_getstr_bounded(&buf, 1000) == EOF) /* receive password */
 725         {
 726                 pfree(buf.data);
 727                 return STATUS_EOF;
 728         }
 729
 730         /*
 731          * We don't actually use the password packet length the frontend sent
 732          * us; however, it's a reasonable sanity check to ensure that we
 733          * actually read as much data as we expected to.
 734          *
 735          * The password packet size is the length of the buffer, plus the size
 736          * field itself (4 bytes), plus a 1-byte terminator.
 737          */
 738         if (len != (buf.len + 4 + 1))
 739                 elog(LOG, "unexpected password packet size: read %d, expected %d",
 740                          buf.len + 4 + 1, len);
 741
 742         /* Do not echo password to logs, for security. */
 743         elog(DEBUG5, "received password packet");
 744
 745         result = md5_crypt_verify(port, port->user_name, buf.data);
 746
 747         pfree(buf.data);
 748         return result;
 749 }