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) 1996-2001, 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 1.78 2002/03/05 06:52:05 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 #include "libpq/auth.h"
  29 #include "libpq/crypt.h"
  30 #include "libpq/hba.h"
  31 #include "libpq/libpq.h"
  32 #include "libpq/password.h"
  33 #include "libpq/pqformat.h"
  34 #include "miscadmin.h"
  35
  36 static void sendAuthRequest(Port *port, AuthRequest areq);
  37 static int      checkPassword(Port *port, char *user, char *password);
  38 static int      old_be_recvauth(Port *port);
  39 static int      map_old_to_new(Port *port, UserAuth old, int status);
  40 static void auth_failed(Port *port, int status);
  41 static int      recv_and_check_password_packet(Port *port);
  42 static int      recv_and_check_passwordv0(Port *port);
  43
  44 char       *pg_krb_server_keyfile;
  45
  46 #ifdef USE_PAM
  47 #include <security/pam_appl.h>
  48
  49 #define PGSQL_PAM_SERVICE "postgresql"  /* Service name passed to PAM */
  50
  51 static int      CheckPAMAuth(Port *port, char *user, char *password);
  52 static int pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg,
  53                                          struct pam_response ** resp, void *appdata_ptr);
  54
  55 static struct pam_conv pam_passw_conv = {
  56         &pam_passwd_conv_proc,
  57         NULL
  58 };
  59
  60 static char *pam_passwd = NULL; /* Workaround for Solaris 2.6 brokenness */
  61 static Port *pam_port_cludge;   /* Workaround for passing "Port *port"
  62                                                                  * into pam_passwd_conv_proc */
  63 #endif   /* USE_PAM */
  64
  65 #ifdef KRB4
  66 /*----------------------------------------------------------------
  67  * MIT Kerberos authentication system - protocol version 4
  68  *----------------------------------------------------------------
  69  */
  70
  71 #include "krb.h"
  72
  73 /*
  74  * pg_krb4_recvauth -- server routine to receive authentication information
  75  *                                         from the client
  76  *
  77  * Nothing unusual here, except that we compare the username obtained from
  78  * the client's setup packet to the authenticated name.  (We have to retain
  79  * the name in the setup packet since we have to retain the ability to handle
  80  * unauthenticated connections.)
  81  */
  82 static int
  83 pg_krb4_recvauth(Port *port)
  84 {
  85         long            krbopts = 0;    /* one-way authentication */
  86         KTEXT_ST        clttkt;
  87         char            instance[INST_SZ + 1],
  88                                 version[KRB_SENDAUTH_VLEN + 1];
  89         AUTH_DAT        auth_data;
  90         Key_schedule key_sched;
  91         int                     status;
  92
  93         strcpy(instance, "*");          /* don't care, but arg gets expanded
  94                                                                  * anyway */
  95         status = krb_recvauth(krbopts,
  96                                                   port->sock,
  97                                                   &clttkt,
  98                                                   PG_KRB_SRVNAM,
  99                                                   instance,
 100                                                   &port->raddr.in,
 101                                                   &port->laddr.in,
 102                                                   &auth_data,
 103                                                   pg_krb_server_keyfile,
 104                                                   key_sched,
 105                                                   version);
 106         if (status != KSUCCESS)
 107         {
 108                 elog(LOG, "pg_krb4_recvauth: kerberos error: %s",
 109                          krb_err_txt[status]);
 110                 return STATUS_ERROR;
 111         }
 112         if (strncmp(version, PG_KRB4_VERSION, KRB_SENDAUTH_VLEN) != 0)
 113         {
 114                 elog(LOG, "pg_krb4_recvauth: protocol version \"%s\" != \"%s\"",
 115                          version, PG_KRB4_VERSION);
 116                 return STATUS_ERROR;
 117         }
 118         if (strncmp(port->user, auth_data.pname, SM_USER) != 0)
 119         {
 120                 elog(LOG, "pg_krb4_recvauth: name \"%s\" != \"%s\"",
 121                          port->user, auth_data.pname);
 122                 return STATUS_ERROR;
 123         }
 124         return STATUS_OK;
 125 }
 126
 127 #else
 128
 129 static int
 130 pg_krb4_recvauth(Port *port)
 131 {
 132         elog(LOG, "pg_krb4_recvauth: Kerberos not implemented on this server");
 133         return STATUS_ERROR;
 134 }
 135
 136 #endif   /* KRB4 */
 137
 138
 139 #ifdef KRB5
 140 /*----------------------------------------------------------------
 141  * MIT Kerberos authentication system - protocol version 5
 142  *----------------------------------------------------------------
 143  */
 144
 145 #include <krb5.h>
 146 #include <com_err.h>
 147
 148 /*
 149  * pg_an_to_ln -- return the local name corresponding to an authentication
 150  *                                name
 151  *
 152  * XXX Assumes that the first aname component is the user name.  This is NOT
 153  *         necessarily so, since an aname can actually be something out of your
 154  *         worst X.400 nightmare, like
 155  *                ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
 156  *         Note that the MIT an_to_ln code does the same thing if you don't
 157  *         provide an aname mapping database...it may be a better idea to use
 158  *         krb5_an_to_ln, except that it punts if multiple components are found,
 159  *         and we can't afford to punt.
 160  */
 161 static char *
 162 pg_an_to_ln(char *aname)
 163 {
 164         char       *p;
 165
 166         if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
 167                 *p = '\0';
 168         return aname;
 169 }
 170
 171
 172 /*
 173  * Various krb5 state which is not connection specfic, and a flag to
 174  * indicate whether we have initialised it yet.
 175  */
 176 static int      pg_krb5_initialised;
 177 static krb5_context pg_krb5_context;
 178 static krb5_keytab pg_krb5_keytab;
 179 static krb5_principal pg_krb5_server;
 180
 181
 182 static int
 183 pg_krb5_init(void)
 184 {
 185         krb5_error_code retval;
 186
 187         if (pg_krb5_initialised)
 188                 return STATUS_OK;
 189
 190         retval = krb5_init_context(&pg_krb5_context);
 191         if (retval)
 192         {
 193                 elog(LOG, "pg_krb5_init: krb5_init_context returned Kerberos error %d",
 194                          retval);
 195                 com_err("postgres", retval, "while initializing krb5");
 196                 return STATUS_ERROR;
 197         }
 198
 199         retval = krb5_kt_resolve(pg_krb5_context, pg_krb_server_keyfile, &pg_krb5_keytab);
 200         if (retval)
 201         {
 202                 elog(LOG, "pg_krb5_init: krb5_kt_resolve returned Kerberos error %d",
 203                          retval);
 204                 com_err("postgres", retval, "while resolving keytab file %s",
 205                                 pg_krb_server_keyfile);
 206                 krb5_free_context(pg_krb5_context);
 207                 return STATUS_ERROR;
 208         }
 209
 210         retval = krb5_sname_to_principal(pg_krb5_context, NULL, PG_KRB_SRVNAM,
 211                                                                          KRB5_NT_SRV_HST, &pg_krb5_server);
 212         if (retval)
 213         {
 214                 elog(LOG, "pg_krb5_init: krb5_sname_to_principal returned Kerberos error %d",
 215                          retval);
 216                 com_err("postgres", retval,
 217                                 "while getting server principal for service %s",
 218                                 PG_KRB_SRVNAM);
 219                 krb5_kt_close(pg_krb5_context, pg_krb5_keytab);
 220                 krb5_free_context(pg_krb5_context);
 221                 return STATUS_ERROR;
 222         }
 223
 224         pg_krb5_initialised = 1;
 225         return STATUS_OK;
 226 }
 227
 228
 229 /*
 230  * pg_krb5_recvauth -- server routine to receive authentication information
 231  *                                         from the client
 232  *
 233  * We still need to compare the username obtained from the client's setup
 234  * packet to the authenticated name, as described in pg_krb4_recvauth.  This
 235  * is a bit more problematic in v5, as described above in pg_an_to_ln.
 236  *
 237  * We have our own keytab file because postgres is unlikely to run as root,
 238  * and so cannot read the default keytab.
 239  */
 240 static int
 241 pg_krb5_recvauth(Port *port)
 242 {
 243         krb5_error_code retval;
 244         int                     ret;
 245         krb5_auth_context auth_context = NULL;
 246         krb5_ticket *ticket;
 247         char       *kusername;
 248
 249         ret = pg_krb5_init();
 250         if (ret != STATUS_OK)
 251                 return ret;
 252
 253         retval = krb5_recvauth(pg_krb5_context, &auth_context,
 254                                                    (krb5_pointer) & port->sock, PG_KRB_SRVNAM,
 255                                                    pg_krb5_server, 0, pg_krb5_keytab, &ticket);
 256         if (retval)
 257         {
 258                 elog(LOG, "pg_krb5_recvauth: krb5_recvauth returned Kerberos error %d",
 259                          retval);
 260                 com_err("postgres", retval, "from krb5_recvauth");
 261                 return STATUS_ERROR;
 262         }
 263
 264         /*
 265          * The "client" structure comes out of the ticket and is therefore
 266          * authenticated.  Use it to check the username obtained from the
 267          * postmaster startup packet.
 268          *
 269          * I have no idea why this is considered necessary.
 270          */
 271 #if defined(HAVE_KRB5_TICKET_ENC_PART2)
 272         retval = krb5_unparse_name(pg_krb5_context,
 273                                                            ticket->enc_part2->client, &kusername);
 274 #elif defined(HAVE_KRB5_TICKET_CLIENT)
 275         retval = krb5_unparse_name(pg_krb5_context,
 276                                                            ticket->client, &kusername);
 277 #else
 278 #error "bogus configuration"
 279 #endif
 280         if (retval)
 281         {
 282                 elog(LOG, "pg_krb5_recvauth: krb5_unparse_name returned Kerberos error %d",
 283                          retval);
 284                 com_err("postgres", retval, "while unparsing client name");
 285                 krb5_free_ticket(pg_krb5_context, ticket);
 286                 krb5_auth_con_free(pg_krb5_context, auth_context);
 287                 return STATUS_ERROR;
 288         }
 289
 290         kusername = pg_an_to_ln(kusername);
 291         if (strncmp(port->user, kusername, SM_USER))
 292         {
 293                 elog(LOG, "pg_krb5_recvauth: user name \"%s\" != krb5 name \"%s\"",
 294                          port->user, kusername);
 295                 ret = STATUS_ERROR;
 296         }
 297         else
 298                 ret = STATUS_OK;
 299
 300         krb5_free_ticket(pg_krb5_context, ticket);
 301         krb5_auth_con_free(pg_krb5_context, auth_context);
 302         free(kusername);
 303
 304         return ret;
 305 }
 306
 307 #else
 308
 309 static int
 310 pg_krb5_recvauth(Port *port)
 311 {
 312         elog(LOG, "pg_krb5_recvauth: Kerberos not implemented on this server");
 313         return STATUS_ERROR;
 314 }
 315
 316 #endif   /* KRB5 */
 317
 318
 319 /*
 320  * Handle a v0 password packet.
 321  */
 322 static int
 323 recv_and_check_passwordv0(Port *port)
 324 {
 325         int32           len;
 326         char       *buf;
 327         PasswordPacketV0 *pp;
 328         char       *user,
 329                            *password,
 330                            *cp,
 331                            *start;
 332         int                     status;
 333
 334         if (pq_getint(&len, 4) == EOF)
 335                 return STATUS_EOF;
 336         len -= 4;
 337         buf = palloc(len);
 338         if (pq_getbytes(buf, len) == EOF)
 339         {
 340                 pfree(buf);
 341                 return STATUS_EOF;
 342         }
 343
 344         pp = (PasswordPacketV0 *) buf;
 345
 346         /*
 347          * The packet is supposed to comprise the user name and the password
 348          * as C strings.  Be careful to check that this is the case.
 349          */
 350         user = password = NULL;
 351
 352         len -= sizeof(pp->unused);
 353
 354         cp = start = pp->data;
 355
 356         while (len-- > 0)
 357                 if (*cp++ == '\0')
 358                 {
 359                         if (user == NULL)
 360                                 user = start;
 361                         else
 362                         {
 363                                 password = start;
 364                                 break;
 365                         }
 366
 367                         start = cp;
 368                 }
 369
 370         if (user == NULL || password == NULL)
 371         {
 372                 elog(LOG, "pg_password_recvauth: badly formed password packet");
 373                 status = STATUS_ERROR;
 374         }
 375         else
 376         {
 377                 UserAuth        saved;
 378
 379                 /* Check the password. */
 380
 381                 saved = port->auth_method;
 382                 port->auth_method = uaPassword;
 383
 384                 status = checkPassword(port, user, password);
 385
 386                 port->auth_method = saved;
 387
 388                 /* Adjust the result if necessary. */
 389                 if (map_old_to_new(port, uaPassword, status) != STATUS_OK)
 390                         status = STATUS_ERROR;
 391         }
 392
 393         pfree(buf);
 394
 395         return status;
 396 }
 397
 398
 399 /*
 400  * Tell the user the authentication failed, but not (much about) why.
 401  *
 402  * There is a tradeoff here between security concerns and making life
 403  * unnecessarily difficult for legitimate users.  We would not, for example,
 404  * want to report the password we were expecting to receive...
 405  * But it seems useful to report the username and authorization method
 406  * in use, and these are items that must be presumed known to an attacker
 407  * anyway.
 408  * Note that many sorts of failure report additional information in the
 409  * postmaster log, which we hope is only readable by good guys.
 410  */
 411 static void
 412 auth_failed(Port *port, int status)
 413 {
 414         const char *authmethod = "Unknown auth method:";
 415
 416         /*
 417          * If we failed due to EOF from client, just quit; there's no point in
 418          * trying to send a message to the client, and not much point in
 419          * logging the failure in the postmaster log.  (Logging the failure
 420          * might be desirable, were it not for the fact that libpq closes the
 421          * connection unceremoniously if challenged for a password when it
 422          * hasn't got one to send.  We'll get a useless log entry for every
 423          * psql connection under password auth, even if it's perfectly
 424          * successful, if we log STATUS_EOF events.)
 425          */
 426         if (status == STATUS_EOF)
 427                 proc_exit(0);
 428
 429         switch (port->auth_method)
 430         {
 431                 case uaReject:
 432                         authmethod = "Rejected host:";
 433                         break;
 434                 case uaKrb4:
 435                         authmethod = "Kerberos4";
 436                         break;
 437                 case uaKrb5:
 438                         authmethod = "Kerberos5";
 439                         break;
 440                 case uaTrust:
 441                         authmethod = "Trusted";
 442                         break;
 443                 case uaIdent:
 444                         authmethod = "IDENT";
 445                         break;
 446                 case uaMD5:
 447                 case uaCrypt:
 448                 case uaPassword:
 449                         authmethod = "Password";
 450                         break;
 451 #ifdef USE_PAM
 452                 case uaPAM:
 453                         authmethod = "PAM";
 454                         break;
 455 #endif   /* USE_PAM */
 456         }
 457
 458         elog(FATAL, "%s authentication failed for user \"%s\"",
 459                  authmethod, port->user);
 460         /* doesn't return */
 461 }
 462
 463
 464 /*
 465  * Client authentication starts here.  If there is an error, this
 466  * function does not return and the backend process is terminated.
 467  */
 468 void
 469 ClientAuthentication(Port *port)
 470 {
 471         int                     status = STATUS_ERROR;
 472
 473         /*
 474          * Get the authentication method to use for this frontend/database
 475          * combination.  Note: a failure return indicates a problem with the
 476          * hba config file, not with the request.  hba.c should have dropped
 477          * an error message into the postmaster logfile if it failed.
 478          */
 479         if (hba_getauthmethod(port) != STATUS_OK)
 480                 elog(FATAL, "Missing or erroneous pg_hba.conf file, see postmaster log for details");
 481
 482         /* Handle old style authentication. */
 483         if (PG_PROTOCOL_MAJOR(port->proto) == 0)
 484         {
 485                 status = old_be_recvauth(port);
 486                 if (status != STATUS_OK)
 487                         auth_failed(port, status);
 488                 return;
 489         }
 490
 491         /* Handle new style authentication. */
 492         switch (port->auth_method)
 493         {
 494                 case uaReject:
 495
 496                         /*
 497                          * This could have come from an explicit "reject" entry in
 498                          * pg_hba.conf, but more likely it means there was no matching
 499                          * entry.  Take pity on the poor user and issue a helpful
 500                          * error message.  NOTE: this is not a security breach,
 501                          * because all the info reported here is known at the frontend
 502                          * and must be assumed known to bad guys. We're merely helping
 503                          * out the less clueful good guys.
 504                          */
 505                         {
 506                                 const char *hostinfo = "localhost";
 507
 508                                 if (port->raddr.sa.sa_family == AF_INET)
 509                                         hostinfo = inet_ntoa(port->raddr.in.sin_addr);
 510                                 elog(FATAL,
 511                                          "No pg_hba.conf entry for host %s, user %s, database %s",
 512                                          hostinfo, port->user, port->database);
 513                                 break;
 514                         }
 515
 516                 case uaKrb4:
 517                         sendAuthRequest(port, AUTH_REQ_KRB4);
 518                         status = pg_krb4_recvauth(port);
 519                         break;
 520
 521                 case uaKrb5:
 522                         sendAuthRequest(port, AUTH_REQ_KRB5);
 523                         status = pg_krb5_recvauth(port);
 524                         break;
 525
 526                 case uaIdent:
 527 #if !defined(SO_PEERCRED) && (defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS)))
 528
 529                         /*
 530                          * If we are doing ident on unix-domain sockets, use SCM_CREDS
 531                          * only if it is defined and SO_PEERCRED isn't.
 532                          */
 533 #if defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
 534
 535                         /*
 536                          * Receive credentials on next message receipt, BSD/OS,
 537                          * NetBSD. We need to set this before the client sends the
 538                          * next packet.
 539                          */
 540                         {
 541                                 int                     on = 1;
 542
 543                                 if (setsockopt(port->sock, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
 544                                         elog(FATAL, "pg_local_sendauth: can't do setsockopt: %m");
 545                         }
 546 #endif
 547                         if (port->raddr.sa.sa_family == AF_UNIX)
 548                                 sendAuthRequest(port, AUTH_REQ_SCM_CREDS);
 549 #endif
 550                         status = authident(port);
 551                         break;
 552
 553                 case uaMD5:
 554                         sendAuthRequest(port, AUTH_REQ_MD5);
 555                         status = recv_and_check_password_packet(port);
 556                         break;
 557
 558                 case uaCrypt:
 559                         sendAuthRequest(port, AUTH_REQ_CRYPT);
 560                         status = recv_and_check_password_packet(port);
 561                         break;
 562
 563                 case uaPassword:
 564                         sendAuthRequest(port, AUTH_REQ_PASSWORD);
 565                         status = recv_and_check_password_packet(port);
 566                         break;
 567
 568 #ifdef USE_PAM
 569                 case uaPAM:
 570                         pam_port_cludge = port;
 571                         status = CheckPAMAuth(port, port->user, "");
 572                         break;
 573 #endif   /* USE_PAM */
 574
 575                 case uaTrust:
 576                         status = STATUS_OK;
 577                         break;
 578         }
 579
 580         if (status == STATUS_OK)
 581                 sendAuthRequest(port, AUTH_REQ_OK);
 582         else
 583                 auth_failed(port, status);
 584 }
 585
 586
 587 /*
 588  * Send an authentication request packet to the frontend.
 589  */
 590 static void
 591 sendAuthRequest(Port *port, AuthRequest areq)
 592 {
 593         StringInfoData buf;
 594
 595         pq_beginmessage(&buf);
 596         pq_sendbyte(&buf, 'R');
 597         pq_sendint(&buf, (int32) areq, sizeof(int32));
 598
 599         /* Add the salt for encrypted passwords. */
 600         if (areq == AUTH_REQ_MD5)
 601                 pq_sendbytes(&buf, port->md5Salt, 4);
 602         else if (areq == AUTH_REQ_CRYPT)
 603                 pq_sendbytes(&buf, port->cryptSalt, 2);
 604
 605         pq_endmessage(&buf);
 606
 607         /*
 608          * Flush message so client will see it, except for AUTH_REQ_OK,
 609          * which need not be sent until we are ready for queries.
 610          */
 611         if (areq != AUTH_REQ_OK)
 612                 pq_flush();
 613 }
 614
 615
 616 #ifdef USE_PAM
 617
 618 /*
 619  * PAM conversation function
 620  */
 621
 622 static int
 623 pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg, struct pam_response ** resp, void *appdata_ptr)
 624 {
 625         StringInfoData buf;
 626         int32           len;
 627
 628         if (num_msg != 1 || msg[0]->msg_style != PAM_PROMPT_ECHO_OFF)
 629         {
 630                 switch (msg[0]->msg_style)
 631                 {
 632                         case PAM_ERROR_MSG:
 633                                 elog(LOG, "pam_passwd_conv_proc: Error from underlying PAM layer: '%s'",
 634                                          msg[0]->msg);
 635                                 return PAM_CONV_ERR;
 636                         default:
 637                                 elog(LOG, "pam_passwd_conv_proc: Unexpected PAM conversation %d/'%s'",
 638                                          msg[0]->msg_style, msg[0]->msg);
 639                                 return PAM_CONV_ERR;
 640                 }
 641         }
 642
 643         if (!appdata_ptr)
 644         {
 645                 /*
 646                  * Workaround for Solaris 2.6 where the PAM library is broken and
 647                  * does not pass appdata_ptr to the conversation routine
 648                  */
 649                 appdata_ptr = pam_passwd;
 650         }
 651
 652         /*
 653          * Password wasn't passed to PAM the first time around - let's go ask
 654          * the client to send a password, which we then stuff into PAM.
 655          */
 656         if (strlen(appdata_ptr) == 0)
 657         {
 658                 sendAuthRequest(pam_port_cludge, AUTH_REQ_PASSWORD);
 659                 if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
 660                 {
 661                         return PAM_CONV_ERR;    /* client didn't want to send password */
 662                 }
 663
 664                 initStringInfo(&buf);
 665                 pq_getstr(&buf);
 666                 elog(DEBUG5, "received PAM packet with len=%d, pw=%s", len, buf.data);
 667
 668                 if (strlen(buf.data) == 0)
 669                 {
 670                         elog(LOG, "pam_passwd_conv_proc: no password");
 671                         return PAM_CONV_ERR;
 672                 }
 673                 appdata_ptr = buf.data;
 674         }
 675
 676         /*
 677          * Explicitly not using palloc here - PAM will free this memory in
 678          * pam_end()
 679          */
 680         *resp = calloc(num_msg, sizeof(struct pam_response));
 681         if (!*resp)
 682         {
 683                 elog(LOG, "pam_passwd_conv_proc: Out of memory!");
 684                 if (buf.data)
 685                         pfree(buf.data);
 686                 return PAM_CONV_ERR;
 687         }
 688
 689         (*resp)[0].resp = strdup((char *) appdata_ptr);
 690         (*resp)[0].resp_retcode = 0;
 691
 692         return ((*resp)[0].resp ? PAM_SUCCESS : PAM_CONV_ERR);
 693 }
 694
 695
 696 /*
 697  * Check authentication against PAM.
 698  */
 699 static int
 700 CheckPAMAuth(Port *port, char *user, char *password)
 701 {
 702         int                     retval;
 703         pam_handle_t *pamh = NULL;
 704
 705         /*
 706          * Apparently, Solaris 2.6 is broken, and needs ugly static variable
 707          * workaround
 708          */
 709         pam_passwd = password;
 710
 711         /*
 712          * Set the application data portion of the conversation struct This is
 713          * later used inside the PAM conversation to pass the password to the
 714          * authentication module.
 715          */
 716         pam_passw_conv.appdata_ptr = (char *) password;         /* from password above,
 717                                                                                                                  * not allocated */
 718
 719         /* Optionally, one can set the service name in pg_hba.conf */
 720         if (port->auth_arg[0] == '\0')
 721                 retval = pam_start(PGSQL_PAM_SERVICE, "pgsql@", &pam_passw_conv, &pamh);
 722         else
 723                 retval = pam_start(port->auth_arg, "pgsql@", &pam_passw_conv, &pamh);
 724
 725         if (retval != PAM_SUCCESS)
 726         {
 727                 elog(LOG, "CheckPAMAuth: Failed to create PAM authenticator: '%s'",
 728                          pam_strerror(pamh, retval));
 729                 pam_passwd = NULL;              /* Unset pam_passwd */
 730                 return STATUS_ERROR;
 731         }
 732
 733         retval = pam_set_item(pamh, PAM_USER, user);
 734
 735         if (retval != PAM_SUCCESS)
 736         {
 737                 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_USER) failed: '%s'",
 738                          pam_strerror(pamh, retval));
 739                 pam_passwd = NULL;              /* Unset pam_passwd */
 740                 return STATUS_ERROR;
 741         }
 742
 743         retval = pam_set_item(pamh, PAM_CONV, &pam_passw_conv);
 744
 745         if (retval != PAM_SUCCESS)
 746         {
 747                 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_CONV) failed: '%s'",
 748                          pam_strerror(pamh, retval));
 749                 pam_passwd = NULL;              /* Unset pam_passwd */
 750                 return STATUS_ERROR;
 751         }
 752
 753         retval = pam_authenticate(pamh, 0);
 754
 755         if (retval != PAM_SUCCESS)
 756         {
 757                 elog(LOG, "CheckPAMAuth: pam_authenticate failed: '%s'",
 758                          pam_strerror(pamh, retval));
 759                 pam_passwd = NULL;              /* Unset pam_passwd */
 760                 return STATUS_ERROR;
 761         }
 762
 763         retval = pam_acct_mgmt(pamh, 0);
 764
 765         if (retval != PAM_SUCCESS)
 766         {
 767                 elog(LOG, "CheckPAMAuth: pam_acct_mgmt failed: '%s'",
 768                          pam_strerror(pamh, retval));
 769                 pam_passwd = NULL;              /* Unset pam_passwd */
 770                 return STATUS_ERROR;
 771         }
 772
 773         retval = pam_end(pamh, retval);
 774
 775         if (retval != PAM_SUCCESS)
 776         {
 777                 elog(LOG, "CheckPAMAuth: Failed to release PAM authenticator: '%s'",
 778                          pam_strerror(pamh, retval));
 779         }
 780
 781         pam_passwd = NULL;              /* Unset pam_passwd */
 782
 783         return (retval == PAM_SUCCESS ? STATUS_OK : STATUS_ERROR);
 784 }
 785 #endif   /* USE_PAM */
 786
 787
 788 /*
 789  * Called when we have received the password packet.
 790  */
 791 static int
 792 recv_and_check_password_packet(Port *port)
 793 {
 794         StringInfoData buf;
 795         int32           len;
 796         int                     result;
 797
 798         if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
 799                 return STATUS_EOF;              /* client didn't want to send password */
 800
 801         initStringInfo(&buf);
 802         if (pq_getstr(&buf) == EOF) /* receive password */
 803         {
 804                 pfree(buf.data);
 805                 return STATUS_EOF;
 806         }
 807
 808         /* Do not echo failed password to logs, for security. */
 809         elog(DEBUG5, "received password packet");
 810
 811         result = checkPassword(port, port->user, buf.data);
 812         pfree(buf.data);
 813         return result;
 814 }
 815
 816
 817 /*
 818  * Handle `password' and `crypt' records. If an auth argument was
 819  * specified, use the respective file. Else use pg_shadow passwords.
 820  */
 821 static int
 822 checkPassword(Port *port, char *user, char *password)
 823 {
 824         if (port->auth_arg[0] != '\0')
 825                 return verify_password(port, user, password);
 826
 827         return md5_crypt_verify(port, user, password);
 828 }
 829
 830
 831 /*
 832  * Server demux routine for incoming authentication information for protocol
 833  * version 0.
 834  */
 835 static int
 836 old_be_recvauth(Port *port)
 837 {
 838         int                     status;
 839         MsgType         msgtype = (MsgType) port->proto;
 840
 841         /* Handle the authentication that's offered. */
 842         switch (msgtype)
 843         {
 844                 case STARTUP_KRB4_MSG:
 845                         status = map_old_to_new(port, uaKrb4, pg_krb4_recvauth(port));
 846                         break;
 847
 848                 case STARTUP_KRB5_MSG:
 849                         status = map_old_to_new(port, uaKrb5, pg_krb5_recvauth(port));
 850                         break;
 851
 852                 case STARTUP_MSG:
 853                         status = map_old_to_new(port, uaTrust, STATUS_OK);
 854                         break;
 855
 856                 case STARTUP_PASSWORD_MSG:
 857                         status = recv_and_check_passwordv0(port);
 858                         break;
 859
 860                 default:
 861                         elog(LOG, "Invalid startup message type: %u", msgtype);
 862
 863                         return STATUS_ERROR;
 864         }
 865
 866         return status;
 867 }
 868
 869
 870 /*
 871  * The old style authentication has been done.  Modify the result of this (eg.
 872  * allow the connection anyway, disallow it anyway, or use the result)
 873  * depending on what authentication we really want to use.
 874  */
 875 static int
 876 map_old_to_new(Port *port, UserAuth old, int status)
 877 {
 878         switch (port->auth_method)
 879         {
 880                 case uaMD5:
 881                 case uaCrypt:
 882                 case uaReject:
 883 #ifdef USE_PAM
 884                 case uaPAM:
 885 #endif   /* USE_PAM */
 886                         status = STATUS_ERROR;
 887                         break;
 888
 889                 case uaKrb4:
 890                         if (old != uaKrb4)
 891                                 status = STATUS_ERROR;
 892                         break;
 893
 894                 case uaKrb5:
 895                         if (old != uaKrb5)
 896                                 status = STATUS_ERROR;
 897                         break;
 898
 899                 case uaTrust:
 900                         status = STATUS_OK;
 901                         break;
 902
 903                 case uaIdent:
 904                         status = authident(port);
 905                         break;
 906
 907                 case uaPassword:
 908                         if (old != uaPassword)
 909                                 status = STATUS_ERROR;
 910
 911                         break;
 912         }
 913
 914         return status;
 915 }