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 1.88 2002/08/30 16:00:41 momjian Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15
  16 #include "postgres.h"
  17
  18 #include <sys/types.h>
  19 #include <sys/param.h>
  20 #include <sys/socket.h>
  21 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
  22 #include <sys/uio.h>
  23 #include <sys/ucred.h>
  24 #include <errno.h>
  25 #endif
  26 #include <netinet/in.h>
  27 #include <arpa/inet.h>
  28
  29 #include "libpq/auth.h"
  30 #include "libpq/crypt.h"
  31 #include "libpq/hba.h"
  32 #include "libpq/libpq.h"
  33 #include "libpq/password.h"
  34 #include "libpq/pqformat.h"
  35 #include "miscadmin.h"
  36 #include "storage/ipc.h"
  37
  38
  39 static void sendAuthRequest(Port *port, AuthRequest areq);
  40 static void auth_failed(Port *port, int status);
  41 static int      recv_and_check_password_packet(Port *port);
  42
  43 char       *pg_krb_server_keyfile;
  44
  45 #ifdef USE_PAM
  46 #include <security/pam_appl.h>
  47
  48 #define PGSQL_PAM_SERVICE "postgresql"  /* Service name passed to PAM */
  49
  50 static int      CheckPAMAuth(Port *port, char *user, char *password);
  51 static int pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg,
  52                                          struct pam_response ** resp, void *appdata_ptr);
  53
  54 static struct pam_conv pam_passw_conv = {
  55         &pam_passwd_conv_proc,
  56         NULL
  57 };
  58
  59 static char *pam_passwd = NULL; /* Workaround for Solaris 2.6 brokenness */
  60 static Port *pam_port_cludge;   /* Workaround for passing "Port *port"
  61                                                                  * into pam_passwd_conv_proc */
  62 #endif   /* USE_PAM */
  63
  64 #ifdef KRB4
  65 /*----------------------------------------------------------------
  66  * MIT Kerberos authentication system - protocol version 4
  67  *----------------------------------------------------------------
  68  */
  69
  70 #include "krb.h"
  71
  72 /*
  73  * pg_krb4_recvauth -- server routine to receive authentication information
  74  *                                         from the client
  75  *
  76  * Nothing unusual here, except that we compare the username obtained from
  77  * the client's setup packet to the authenticated name.  (We have to retain
  78  * the name in the setup packet since we have to retain the ability to handle
  79  * unauthenticated connections.)
  80  */
  81 static int
  82 pg_krb4_recvauth(Port *port)
  83 {
  84         long            krbopts = 0;    /* one-way authentication */
  85         KTEXT_ST        clttkt;
  86         char            instance[INST_SZ + 1],
  87                                 version[KRB_SENDAUTH_VLEN + 1];
  88         AUTH_DAT        auth_data;
  89         Key_schedule key_sched;
  90         int                     status;
  91
  92         strcpy(instance, "*");          /* don't care, but arg gets expanded
  93                                                                  * anyway */
  94         status = krb_recvauth(krbopts,
  95                                                   port->sock,
  96                                                   &clttkt,
  97                                                   PG_KRB_SRVNAM,
  98                                                   instance,
  99                                                   &port->raddr.in,
 100                                                   &port->laddr.in,
 101                                                   &auth_data,
 102                                                   pg_krb_server_keyfile,
 103                                                   key_sched,
 104                                                   version);
 105         if (status != KSUCCESS)
 106         {
 107                 elog(LOG, "pg_krb4_recvauth: kerberos error: %s",
 108                          krb_err_txt[status]);
 109                 return STATUS_ERROR;
 110         }
 111         if (strncmp(version, PG_KRB4_VERSION, KRB_SENDAUTH_VLEN) != 0)
 112         {
 113                 elog(LOG, "pg_krb4_recvauth: protocol version \"%s\" != \"%s\"",
 114                          version, PG_KRB4_VERSION);
 115                 return STATUS_ERROR;
 116         }
 117         if (strncmp(port->user, auth_data.pname, SM_DATABASE_USER) != 0)
 118         {
 119                 elog(LOG, "pg_krb4_recvauth: name \"%s\" != \"%s\"",
 120                          port->user, auth_data.pname);
 121                 return STATUS_ERROR;
 122         }
 123         return STATUS_OK;
 124 }
 125
 126 #else
 127
 128 static int
 129 pg_krb4_recvauth(Port *port)
 130 {
 131         elog(LOG, "pg_krb4_recvauth: Kerberos not implemented on this server");
 132         return STATUS_ERROR;
 133 }
 134
 135 #endif   /* KRB4 */
 136
 137
 138 #ifdef KRB5
 139 /*----------------------------------------------------------------
 140  * MIT Kerberos authentication system - protocol version 5
 141  *----------------------------------------------------------------
 142  */
 143
 144 #include <krb5.h>
 145 #include <com_err.h>
 146
 147 /*
 148  * pg_an_to_ln -- return the local name corresponding to an authentication
 149  *                                name
 150  *
 151  * XXX Assumes that the first aname component is the user name.  This is NOT
 152  *         necessarily so, since an aname can actually be something out of your
 153  *         worst X.400 nightmare, like
 154  *                ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
 155  *         Note that the MIT an_to_ln code does the same thing if you don't
 156  *         provide an aname mapping database...it may be a better idea to use
 157  *         krb5_an_to_ln, except that it punts if multiple components are found,
 158  *         and we can't afford to punt.
 159  */
 160 static char *
 161 pg_an_to_ln(char *aname)
 162 {
 163         char       *p;
 164
 165         if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
 166                 *p = '\0';
 167         return aname;
 168 }
 169
 170
 171 /*
 172  * Various krb5 state which is not connection specfic, and a flag to
 173  * indicate whether we have initialised it yet.
 174  */
 175 static int      pg_krb5_initialised;
 176 static krb5_context pg_krb5_context;
 177 static krb5_keytab pg_krb5_keytab;
 178 static krb5_principal pg_krb5_server;
 179
 180
 181 static int
 182 pg_krb5_init(void)
 183 {
 184         krb5_error_code retval;
 185
 186         if (pg_krb5_initialised)
 187                 return STATUS_OK;
 188
 189         retval = krb5_init_context(&pg_krb5_context);
 190         if (retval)
 191         {
 192                 elog(LOG, "pg_krb5_init: krb5_init_context returned Kerberos error %d",
 193                          retval);
 194                 com_err("postgres", retval, "while initializing krb5");
 195                 return STATUS_ERROR;
 196         }
 197
 198         retval = krb5_kt_resolve(pg_krb5_context, pg_krb_server_keyfile, &pg_krb5_keytab);
 199         if (retval)
 200         {
 201                 elog(LOG, "pg_krb5_init: krb5_kt_resolve returned Kerberos error %d",
 202                          retval);
 203                 com_err("postgres", retval, "while resolving keytab file %s",
 204                                 pg_krb_server_keyfile);
 205                 krb5_free_context(pg_krb5_context);
 206                 return STATUS_ERROR;
 207         }
 208
 209         retval = krb5_sname_to_principal(pg_krb5_context, NULL, PG_KRB_SRVNAM,
 210                                                                          KRB5_NT_SRV_HST, &pg_krb5_server);
 211         if (retval)
 212         {
 213                 elog(LOG, "pg_krb5_init: krb5_sname_to_principal returned Kerberos error %d",
 214                          retval);
 215                 com_err("postgres", retval,
 216                                 "while getting server principal for service %s",
 217                                 PG_KRB_SRVNAM);
 218                 krb5_kt_close(pg_krb5_context, pg_krb5_keytab);
 219                 krb5_free_context(pg_krb5_context);
 220                 return STATUS_ERROR;
 221         }
 222
 223         pg_krb5_initialised = 1;
 224         return STATUS_OK;
 225 }
 226
 227
 228 /*
 229  * pg_krb5_recvauth -- server routine to receive authentication information
 230  *                                         from the client
 231  *
 232  * We still need to compare the username obtained from the client's setup
 233  * packet to the authenticated name, as described in pg_krb4_recvauth.  This
 234  * is a bit more problematic in v5, as described above in pg_an_to_ln.
 235  *
 236  * We have our own keytab file because postgres is unlikely to run as root,
 237  * and so cannot read the default keytab.
 238  */
 239 static int
 240 pg_krb5_recvauth(Port *port)
 241 {
 242         krb5_error_code retval;
 243         int                     ret;
 244         krb5_auth_context auth_context = NULL;
 245         krb5_ticket *ticket;
 246         char       *kusername;
 247
 248         ret = pg_krb5_init();
 249         if (ret != STATUS_OK)
 250                 return ret;
 251
 252         retval = krb5_recvauth(pg_krb5_context, &auth_context,
 253                                                    (krb5_pointer) & port->sock, PG_KRB_SRVNAM,
 254                                                    pg_krb5_server, 0, pg_krb5_keytab, &ticket);
 255         if (retval)
 256         {
 257                 elog(LOG, "pg_krb5_recvauth: krb5_recvauth returned Kerberos error %d",
 258                          retval);
 259                 com_err("postgres", retval, "from krb5_recvauth");
 260                 return STATUS_ERROR;
 261         }
 262
 263         /*
 264          * The "client" structure comes out of the ticket and is therefore
 265          * authenticated.  Use it to check the username obtained from the
 266          * postmaster startup packet.
 267          *
 268          * I have no idea why this is considered necessary.
 269          */
 270 #if defined(HAVE_KRB5_TICKET_ENC_PART2)
 271         retval = krb5_unparse_name(pg_krb5_context,
 272                                                            ticket->enc_part2->client, &kusername);
 273 #elif defined(HAVE_KRB5_TICKET_CLIENT)
 274         retval = krb5_unparse_name(pg_krb5_context,
 275                                                            ticket->client, &kusername);
 276 #else
 277 #error "bogus configuration"
 278 #endif
 279         if (retval)
 280         {
 281                 elog(LOG, "pg_krb5_recvauth: krb5_unparse_name returned Kerberos error %d",
 282                          retval);
 283                 com_err("postgres", retval, "while unparsing client name");
 284                 krb5_free_ticket(pg_krb5_context, ticket);
 285                 krb5_auth_con_free(pg_krb5_context, auth_context);
 286                 return STATUS_ERROR;
 287         }
 288
 289         kusername = pg_an_to_ln(kusername);
 290         if (strncmp(port->user, kusername, SM_DATABASE_USER))
 291         {
 292                 elog(LOG, "pg_krb5_recvauth: user name \"%s\" != krb5 name \"%s\"",
 293                          port->user, kusername);
 294                 ret = STATUS_ERROR;
 295         }
 296         else
 297                 ret = STATUS_OK;
 298
 299         krb5_free_ticket(pg_krb5_context, ticket);
 300         krb5_auth_con_free(pg_krb5_context, auth_context);
 301         free(kusername);
 302
 303         return ret;
 304 }
 305
 306 #else
 307
 308 static int
 309 pg_krb5_recvauth(Port *port)
 310 {
 311         elog(LOG, "pg_krb5_recvauth: Kerberos not implemented on this server");
 312         return STATUS_ERROR;
 313 }
 314
 315 #endif   /* KRB5 */
 316
 317
 318 /*
 319  * Tell the user the authentication failed, but not (much about) why.
 320  *
 321  * There is a tradeoff here between security concerns and making life
 322  * unnecessarily difficult for legitimate users.  We would not, for example,
 323  * want to report the password we were expecting to receive...
 324  * But it seems useful to report the username and authorization method
 325  * in use, and these are items that must be presumed known to an attacker
 326  * anyway.
 327  * Note that many sorts of failure report additional information in the
 328  * postmaster log, which we hope is only readable by good guys.
 329  */
 330 static void
 331 auth_failed(Port *port, int status)
 332 {
 333         const char *authmethod = "Unknown auth method:";
 334
 335         /*
 336          * If we failed due to EOF from client, just quit; there's no point in
 337          * trying to send a message to the client, and not much point in
 338          * logging the failure in the postmaster log.  (Logging the failure
 339          * might be desirable, were it not for the fact that libpq closes the
 340          * connection unceremoniously if challenged for a password when it
 341          * hasn't got one to send.  We'll get a useless log entry for every
 342          * psql connection under password auth, even if it's perfectly
 343          * successful, if we log STATUS_EOF events.)
 344          */
 345         if (status == STATUS_EOF)
 346                 proc_exit(0);
 347
 348         switch (port->auth_method)
 349         {
 350                 case uaReject:
 351                         authmethod = "Rejected host:";
 352                         break;
 353                 case uaKrb4:
 354                         authmethod = "Kerberos4";
 355                         break;
 356                 case uaKrb5:
 357                         authmethod = "Kerberos5";
 358                         break;
 359                 case uaTrust:
 360                         authmethod = "Trusted";
 361                         break;
 362                 case uaIdent:
 363                         authmethod = "IDENT";
 364                         break;
 365                 case uaMD5:
 366                 case uaCrypt:
 367                 case uaPassword:
 368                         authmethod = "Password";
 369                         break;
 370 #ifdef USE_PAM
 371                 case uaPAM:
 372                         authmethod = "PAM";
 373                         break;
 374 #endif   /* USE_PAM */
 375         }
 376
 377         elog(FATAL, "%s authentication failed for user \"%s\"",
 378                  authmethod, port->user);
 379         /* doesn't return */
 380 }
 381
 382
 383 /*
 384  * Client authentication starts here.  If there is an error, this
 385  * function does not return and the backend process is terminated.
 386  */
 387 void
 388 ClientAuthentication(Port *port)
 389 {
 390         int                     status = STATUS_ERROR;
 391
 392         /*
 393          * Get the authentication method to use for this frontend/database
 394          * combination.  Note: a failure return indicates a problem with the
 395          * hba config file, not with the request.  hba.c should have dropped
 396          * an error message into the postmaster logfile if it failed.
 397          */
 398         if (hba_getauthmethod(port) != STATUS_OK)
 399                 elog(FATAL, "Missing or erroneous pg_hba.conf file, see postmaster log for details");
 400
 401         switch (port->auth_method)
 402         {
 403                 case uaReject:
 404
 405                         /*
 406                          * This could have come from an explicit "reject" entry in
 407                          * pg_hba.conf, but more likely it means there was no matching
 408                          * entry.  Take pity on the poor user and issue a helpful
 409                          * error message.  NOTE: this is not a security breach,
 410                          * because all the info reported here is known at the frontend
 411                          * and must be assumed known to bad guys. We're merely helping
 412                          * out the less clueful good guys.
 413                          */
 414                         {
 415                                 const char *hostinfo = "localhost";
 416
 417                                 if (port->raddr.sa.sa_family == AF_INET)
 418                                         hostinfo = inet_ntoa(port->raddr.in.sin_addr);
 419                                 elog(FATAL,
 420                                          "No pg_hba.conf entry for host %s, user %s, database %s",
 421                                          hostinfo, port->user, port->database);
 422                                 break;
 423                         }
 424
 425                 case uaKrb4:
 426                         sendAuthRequest(port, AUTH_REQ_KRB4);
 427                         status = pg_krb4_recvauth(port);
 428                         break;
 429
 430                 case uaKrb5:
 431                         sendAuthRequest(port, AUTH_REQ_KRB5);
 432                         status = pg_krb5_recvauth(port);
 433                         break;
 434
 435                 case uaIdent:
 436 #if !defined(SO_PEERCRED) && (defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS)))
 437
 438                         /*
 439                          * If we are doing ident on unix-domain sockets, use SCM_CREDS
 440                          * only if it is defined and SO_PEERCRED isn't.
 441                          */
 442 #if defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
 443
 444                         /*
 445                          * Receive credentials on next message receipt, BSD/OS,
 446                          * NetBSD. We need to set this before the client sends the
 447                          * next packet.
 448                          */
 449                         {
 450                                 int                     on = 1;
 451
 452                                 if (setsockopt(port->sock, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
 453                                         elog(FATAL, "pg_local_sendauth: can't do setsockopt: %m");
 454                         }
 455 #endif
 456                         if (port->raddr.sa.sa_family == AF_UNIX)
 457                                 sendAuthRequest(port, AUTH_REQ_SCM_CREDS);
 458 #endif
 459                         status = authident(port);
 460                         break;
 461
 462                 case uaMD5:
 463                         sendAuthRequest(port, AUTH_REQ_MD5);
 464                         status = recv_and_check_password_packet(port);
 465                         break;
 466
 467                 case uaCrypt:
 468                         sendAuthRequest(port, AUTH_REQ_CRYPT);
 469                         status = recv_and_check_password_packet(port);
 470                         break;
 471
 472                 case uaPassword:
 473                         sendAuthRequest(port, AUTH_REQ_PASSWORD);
 474                         status = recv_and_check_password_packet(port);
 475                         break;
 476
 477 #ifdef USE_PAM
 478                 case uaPAM:
 479                         pam_port_cludge = port;
 480                         status = CheckPAMAuth(port, port->user, "");
 481                         break;
 482 #endif   /* USE_PAM */
 483
 484                 case uaTrust:
 485                         status = STATUS_OK;
 486                         break;
 487         }
 488
 489         if (status == STATUS_OK)
 490                 sendAuthRequest(port, AUTH_REQ_OK);
 491         else
 492                 auth_failed(port, status);
 493 }
 494
 495
 496 /*
 497  * Send an authentication request packet to the frontend.
 498  */
 499 static void
 500 sendAuthRequest(Port *port, AuthRequest areq)
 501 {
 502         StringInfoData buf;
 503
 504         pq_beginmessage(&buf);
 505         pq_sendbyte(&buf, 'R');
 506         pq_sendint(&buf, (int32) areq, sizeof(int32));
 507
 508         /* Add the salt for encrypted passwords. */
 509         if (areq == AUTH_REQ_MD5)
 510                 pq_sendbytes(&buf, port->md5Salt, 4);
 511         else if (areq == AUTH_REQ_CRYPT)
 512                 pq_sendbytes(&buf, port->cryptSalt, 2);
 513
 514         pq_endmessage(&buf);
 515
 516         /*
 517          * Flush message so client will see it, except for AUTH_REQ_OK,
 518          * which need not be sent until we are ready for queries.
 519          */
 520         if (areq != AUTH_REQ_OK)
 521                 pq_flush();
 522 }
 523
 524
 525 #ifdef USE_PAM
 526
 527 /*
 528  * PAM conversation function
 529  */
 530
 531 static int
 532 pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg, struct pam_response ** resp, void *appdata_ptr)
 533 {
 534         StringInfoData buf;
 535         int32           len;
 536
 537         if (num_msg != 1 || msg[0]->msg_style != PAM_PROMPT_ECHO_OFF)
 538         {
 539                 switch (msg[0]->msg_style)
 540                 {
 541                         case PAM_ERROR_MSG:
 542                                 elog(LOG, "pam_passwd_conv_proc: Error from underlying PAM layer: '%s'",
 543                                          msg[0]->msg);
 544                                 return PAM_CONV_ERR;
 545                         default:
 546                                 elog(LOG, "pam_passwd_conv_proc: Unexpected PAM conversation %d/'%s'",
 547                                          msg[0]->msg_style, msg[0]->msg);
 548                                 return PAM_CONV_ERR;
 549                 }
 550         }
 551
 552         if (!appdata_ptr)
 553         {
 554                 /*
 555                  * Workaround for Solaris 2.6 where the PAM library is broken and
 556                  * does not pass appdata_ptr to the conversation routine
 557                  */
 558                 appdata_ptr = pam_passwd;
 559         }
 560
 561         /*
 562          * Password wasn't passed to PAM the first time around - let's go ask
 563          * the client to send a password, which we then stuff into PAM.
 564          */
 565         if (strlen(appdata_ptr) == 0)
 566         {
 567                 sendAuthRequest(pam_port_cludge, AUTH_REQ_PASSWORD);
 568                 if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
 569                 {
 570                         return PAM_CONV_ERR;    /* client didn't want to send password */
 571                 }
 572
 573                 initStringInfo(&buf);
 574                 pq_getstr(&buf);
 575
 576                 /* Do not echo failed password to logs, for security. */
 577                 elog(DEBUG5, "received PAM packet");
 578
 579                 if (strlen(buf.data) == 0)
 580                 {
 581                         elog(LOG, "pam_passwd_conv_proc: no password");
 582                         return PAM_CONV_ERR;
 583                 }
 584                 appdata_ptr = buf.data;
 585         }
 586
 587         /*
 588          * Explicitly not using palloc here - PAM will free this memory in
 589          * pam_end()
 590          */
 591         *resp = calloc(num_msg, sizeof(struct pam_response));
 592         if (!*resp)
 593         {
 594                 elog(LOG, "pam_passwd_conv_proc: Out of memory!");
 595                 if (buf.data)
 596                         pfree(buf.data);
 597                 return PAM_CONV_ERR;
 598         }
 599
 600         (*resp)[0].resp = strdup((char *) appdata_ptr);
 601         (*resp)[0].resp_retcode = 0;
 602
 603         return ((*resp)[0].resp ? PAM_SUCCESS : PAM_CONV_ERR);
 604 }
 605
 606
 607 /*
 608  * Check authentication against PAM.
 609  */
 610 static int
 611 CheckPAMAuth(Port *port, char *user, char *password)
 612 {
 613         int                     retval;
 614         pam_handle_t *pamh = NULL;
 615
 616         /*
 617          * Apparently, Solaris 2.6 is broken, and needs ugly static variable
 618          * workaround
 619          */
 620         pam_passwd = password;
 621
 622         /*
 623          * Set the application data portion of the conversation struct This is
 624          * later used inside the PAM conversation to pass the password to the
 625          * authentication module.
 626          */
 627         pam_passw_conv.appdata_ptr = (char *) password;         /* from password above,
 628                                                                                                                  * not allocated */
 629
 630         /* Optionally, one can set the service name in pg_hba.conf */
 631         if (port->auth_arg[0] == '\0')
 632                 retval = pam_start(PGSQL_PAM_SERVICE, "pgsql@", &pam_passw_conv, &pamh);
 633         else
 634                 retval = pam_start(port->auth_arg, "pgsql@", &pam_passw_conv, &pamh);
 635
 636         if (retval != PAM_SUCCESS)
 637         {
 638                 elog(LOG, "CheckPAMAuth: Failed to create PAM authenticator: '%s'",
 639                          pam_strerror(pamh, retval));
 640                 pam_passwd = NULL;              /* Unset pam_passwd */
 641                 return STATUS_ERROR;
 642         }
 643
 644         retval = pam_set_item(pamh, PAM_USER, user);
 645
 646         if (retval != PAM_SUCCESS)
 647         {
 648                 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_USER) failed: '%s'",
 649                          pam_strerror(pamh, retval));
 650                 pam_passwd = NULL;              /* Unset pam_passwd */
 651                 return STATUS_ERROR;
 652         }
 653
 654         retval = pam_set_item(pamh, PAM_CONV, &pam_passw_conv);
 655
 656         if (retval != PAM_SUCCESS)
 657         {
 658                 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_CONV) failed: '%s'",
 659                          pam_strerror(pamh, retval));
 660                 pam_passwd = NULL;              /* Unset pam_passwd */
 661                 return STATUS_ERROR;
 662         }
 663
 664         retval = pam_authenticate(pamh, 0);
 665
 666         if (retval != PAM_SUCCESS)
 667         {
 668                 elog(LOG, "CheckPAMAuth: pam_authenticate failed: '%s'",
 669                          pam_strerror(pamh, retval));
 670                 pam_passwd = NULL;              /* Unset pam_passwd */
 671                 return STATUS_ERROR;
 672         }
 673
 674         retval = pam_acct_mgmt(pamh, 0);
 675
 676         if (retval != PAM_SUCCESS)
 677         {
 678                 elog(LOG, "CheckPAMAuth: pam_acct_mgmt failed: '%s'",
 679                          pam_strerror(pamh, retval));
 680                 pam_passwd = NULL;              /* Unset pam_passwd */
 681                 return STATUS_ERROR;
 682         }
 683
 684         retval = pam_end(pamh, retval);
 685
 686         if (retval != PAM_SUCCESS)
 687         {
 688                 elog(LOG, "CheckPAMAuth: Failed to release PAM authenticator: '%s'",
 689                          pam_strerror(pamh, retval));
 690         }
 691
 692         pam_passwd = NULL;              /* Unset pam_passwd */
 693
 694         return (retval == PAM_SUCCESS ? STATUS_OK : STATUS_ERROR);
 695 }
 696 #endif   /* USE_PAM */
 697
 698
 699 /*
 700  * Called when we have received the password packet.
 701  */
 702 static int
 703 recv_and_check_password_packet(Port *port)
 704 {
 705         StringInfoData buf;
 706         int32           len;
 707         int                     result;
 708
 709         if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
 710                 return STATUS_EOF;              /* client didn't want to send password */
 711
 712         initStringInfo(&buf);
 713         if (pq_getstr(&buf) == EOF) /* receive password */
 714         {
 715                 pfree(buf.data);
 716                 return STATUS_EOF;
 717         }
 718         /*
 719          * We don't actually use the password packet length the frontend
 720          * sent us; however, it's a reasonable sanity check to ensure that
 721          * we actually read as much data as we expected to.
 722          *
 723          * The password packet size is the length of the buffer, plus the
 724          * size field itself (4 bytes), plus a 1-byte terminator.
 725          */
 726         if (len != (buf.len + 4 + 1))
 727                 elog(LOG, "unexpected password packet size: read %d, expected %d",
 728                          buf.len + 4 + 1, len);
 729
 730         /* Do not echo password to logs, for security. */
 731         elog(DEBUG5, "received password packet");
 732
 733         result = md5_crypt_verify(port, port->user, buf.data);
 734
 735         pfree(buf.data);
 736         return result;
 737 }