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 1.83 2002/08/18 03:03:25 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 int      old_be_recvauth(Port *port);
  41 static int      map_old_to_new(Port *port, UserAuth old, int status);
  42 static void auth_failed(Port *port, int status);
  43 static int      recv_and_check_password_packet(Port *port);
  44 static int      recv_and_check_passwordv0(Port *port);
  45
  46 char       *pg_krb_server_keyfile;
  47
  48 #ifdef USE_PAM
  49 #include <security/pam_appl.h>
  50
  51 #define PGSQL_PAM_SERVICE "postgresql"  /* Service name passed to PAM */
  52
  53 static int      CheckPAMAuth(Port *port, char *user, char *password);
  54 static int pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg,
  55                                          struct pam_response ** resp, void *appdata_ptr);
  56
  57 static struct pam_conv pam_passw_conv = {
  58         &pam_passwd_conv_proc,
  59         NULL
  60 };
  61
  62 static char *pam_passwd = NULL; /* Workaround for Solaris 2.6 brokenness */
  63 static Port *pam_port_cludge;   /* Workaround for passing "Port *port"
  64                                                                  * into pam_passwd_conv_proc */
  65 #endif   /* USE_PAM */
  66
  67 #ifdef KRB4
  68 /*----------------------------------------------------------------
  69  * MIT Kerberos authentication system - protocol version 4
  70  *----------------------------------------------------------------
  71  */
  72
  73 #include "krb.h"
  74
  75 /*
  76  * pg_krb4_recvauth -- server routine to receive authentication information
  77  *                                         from the client
  78  *
  79  * Nothing unusual here, except that we compare the username obtained from
  80  * the client's setup packet to the authenticated name.  (We have to retain
  81  * the name in the setup packet since we have to retain the ability to handle
  82  * unauthenticated connections.)
  83  */
  84 static int
  85 pg_krb4_recvauth(Port *port)
  86 {
  87         long            krbopts = 0;    /* one-way authentication */
  88         KTEXT_ST        clttkt;
  89         char            instance[INST_SZ + 1],
  90                                 version[KRB_SENDAUTH_VLEN + 1];
  91         AUTH_DAT        auth_data;
  92         Key_schedule key_sched;
  93         int                     status;
  94
  95         strcpy(instance, "*");          /* don't care, but arg gets expanded
  96                                                                  * anyway */
  97         status = krb_recvauth(krbopts,
  98                                                   port->sock,
  99                                                   &clttkt,
 100                                                   PG_KRB_SRVNAM,
 101                                                   instance,
 102                                                   &port->raddr.in,
 103                                                   &port->laddr.in,
 104                                                   &auth_data,
 105                                                   pg_krb_server_keyfile,
 106                                                   key_sched,
 107                                                   version);
 108         if (status != KSUCCESS)
 109         {
 110                 elog(LOG, "pg_krb4_recvauth: kerberos error: %s",
 111                          krb_err_txt[status]);
 112                 return STATUS_ERROR;
 113         }
 114         if (strncmp(version, PG_KRB4_VERSION, KRB_SENDAUTH_VLEN) != 0)
 115         {
 116                 elog(LOG, "pg_krb4_recvauth: protocol version \"%s\" != \"%s\"",
 117                          version, PG_KRB4_VERSION);
 118                 return STATUS_ERROR;
 119         }
 120         if (strncmp(port->user, auth_data.pname, SM_DATABASE_USER) != 0)
 121         {
 122                 elog(LOG, "pg_krb4_recvauth: name \"%s\" != \"%s\"",
 123                          port->user, auth_data.pname);
 124                 return STATUS_ERROR;
 125         }
 126         return STATUS_OK;
 127 }
 128
 129 #else
 130
 131 static int
 132 pg_krb4_recvauth(Port *port)
 133 {
 134         elog(LOG, "pg_krb4_recvauth: Kerberos not implemented on this server");
 135         return STATUS_ERROR;
 136 }
 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
 318 #endif   /* KRB5 */
 319
 320
 321 /*
 322  * Handle a v0 password packet.
 323  */
 324 static int
 325 recv_and_check_passwordv0(Port *port)
 326 {
 327         int32           len;
 328         char       *buf;
 329         PasswordPacketV0 *pp;
 330         char       *user,
 331                            *password,
 332                            *cp,
 333                            *start;
 334         int                     status;
 335
 336         if (pq_getint(&len, 4) == EOF)
 337                 return STATUS_EOF;
 338         len -= 4;
 339         buf = palloc(len);
 340         if (pq_getbytes(buf, len) == EOF)
 341         {
 342                 pfree(buf);
 343                 return STATUS_EOF;
 344         }
 345
 346         pp = (PasswordPacketV0 *) buf;
 347
 348         /*
 349          * The packet is supposed to comprise the user name and the password
 350          * as C strings.  Be careful to check that this is the case.
 351          */
 352         user = password = NULL;
 353
 354         len -= sizeof(pp->unused);
 355
 356         cp = start = pp->data;
 357
 358         while (len-- > 0)
 359                 if (*cp++ == '\0')
 360                 {
 361                         if (user == NULL)
 362                                 user = start;
 363                         else
 364                         {
 365                                 password = start;
 366                                 break;
 367                         }
 368
 369                         start = cp;
 370                 }
 371
 372         if (user == NULL || password == NULL)
 373         {
 374                 elog(LOG, "pg_password_recvauth: badly formed password packet");
 375                 status = STATUS_ERROR;
 376         }
 377         else
 378         {
 379                 UserAuth        saved;
 380
 381                 /* Check the password. */
 382
 383                 saved = port->auth_method;
 384                 port->auth_method = uaPassword;
 385
 386                 status = md5_crypt_verify(port, user, password);
 387
 388                 port->auth_method = saved;
 389
 390                 /* Adjust the result if necessary. */
 391                 if (map_old_to_new(port, uaPassword, status) != STATUS_OK)
 392                         status = STATUS_ERROR;
 393         }
 394
 395         pfree(buf);
 396
 397         return status;
 398 }
 399
 400
 401 /*
 402  * Tell the user the authentication failed, but not (much about) why.
 403  *
 404  * There is a tradeoff here between security concerns and making life
 405  * unnecessarily difficult for legitimate users.  We would not, for example,
 406  * want to report the password we were expecting to receive...
 407  * But it seems useful to report the username and authorization method
 408  * in use, and these are items that must be presumed known to an attacker
 409  * anyway.
 410  * Note that many sorts of failure report additional information in the
 411  * postmaster log, which we hope is only readable by good guys.
 412  */
 413 static void
 414 auth_failed(Port *port, int status)
 415 {
 416         const char *authmethod = "Unknown auth method:";
 417
 418         /*
 419          * If we failed due to EOF from client, just quit; there's no point in
 420          * trying to send a message to the client, and not much point in
 421          * logging the failure in the postmaster log.  (Logging the failure
 422          * might be desirable, were it not for the fact that libpq closes the
 423          * connection unceremoniously if challenged for a password when it
 424          * hasn't got one to send.  We'll get a useless log entry for every
 425          * psql connection under password auth, even if it's perfectly
 426          * successful, if we log STATUS_EOF events.)
 427          */
 428         if (status == STATUS_EOF)
 429                 proc_exit(0);
 430
 431         switch (port->auth_method)
 432         {
 433                 case uaReject:
 434                         authmethod = "Rejected host:";
 435                         break;
 436                 case uaKrb4:
 437                         authmethod = "Kerberos4";
 438                         break;
 439                 case uaKrb5:
 440                         authmethod = "Kerberos5";
 441                         break;
 442                 case uaTrust:
 443                         authmethod = "Trusted";
 444                         break;
 445                 case uaIdent:
 446                         authmethod = "IDENT";
 447                         break;
 448                 case uaMD5:
 449                 case uaCrypt:
 450                 case uaPassword:
 451                         authmethod = "Password";
 452                         break;
 453 #ifdef USE_PAM
 454                 case uaPAM:
 455                         authmethod = "PAM";
 456                         break;
 457 #endif   /* USE_PAM */
 458         }
 459
 460         elog(FATAL, "%s authentication failed for user \"%s\"",
 461                  authmethod, port->user);
 462         /* doesn't return */
 463 }
 464
 465
 466 /*
 467  * Client authentication starts here.  If there is an error, this
 468  * function does not return and the backend process is terminated.
 469  */
 470 void
 471 ClientAuthentication(Port *port)
 472 {
 473         int                     status = STATUS_ERROR;
 474
 475         /*
 476          * Get the authentication method to use for this frontend/database
 477          * combination.  Note: a failure return indicates a problem with the
 478          * hba config file, not with the request.  hba.c should have dropped
 479          * an error message into the postmaster logfile if it failed.
 480          */
 481         if (hba_getauthmethod(port) != STATUS_OK)
 482                 elog(FATAL, "Missing or erroneous pg_hba.conf file, see postmaster log for details");
 483
 484         /* Handle old style authentication. */
 485         if (PG_PROTOCOL_MAJOR(port->proto) == 0)
 486         {
 487                 status = old_be_recvauth(port);
 488                 if (status != STATUS_OK)
 489                         auth_failed(port, status);
 490                 return;
 491         }
 492
 493         /* Handle new style authentication. */
 494         switch (port->auth_method)
 495         {
 496                 case uaReject:
 497
 498                         /*
 499                          * This could have come from an explicit "reject" entry in
 500                          * pg_hba.conf, but more likely it means there was no matching
 501                          * entry.  Take pity on the poor user and issue a helpful
 502                          * error message.  NOTE: this is not a security breach,
 503                          * because all the info reported here is known at the frontend
 504                          * and must be assumed known to bad guys. We're merely helping
 505                          * out the less clueful good guys.
 506                          */
 507                         {
 508                                 const char *hostinfo = "localhost";
 509
 510                                 if (port->raddr.sa.sa_family == AF_INET)
 511                                         hostinfo = inet_ntoa(port->raddr.in.sin_addr);
 512                                 elog(FATAL,
 513                                          "No pg_hba.conf entry for host %s, user %s, database %s",
 514                                          hostinfo, port->user, port->database);
 515                                 break;
 516                         }
 517
 518                 case uaKrb4:
 519                         sendAuthRequest(port, AUTH_REQ_KRB4);
 520                         status = pg_krb4_recvauth(port);
 521                         break;
 522
 523                 case uaKrb5:
 524                         sendAuthRequest(port, AUTH_REQ_KRB5);
 525                         status = pg_krb5_recvauth(port);
 526                         break;
 527
 528                 case uaIdent:
 529 #if !defined(SO_PEERCRED) && (defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS)))
 530
 531                         /*
 532                          * If we are doing ident on unix-domain sockets, use SCM_CREDS
 533                          * only if it is defined and SO_PEERCRED isn't.
 534                          */
 535 #if defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
 536
 537                         /*
 538                          * Receive credentials on next message receipt, BSD/OS,
 539                          * NetBSD. We need to set this before the client sends the
 540                          * next packet.
 541                          */
 542                         {
 543                                 int                     on = 1;
 544
 545                                 if (setsockopt(port->sock, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
 546                                         elog(FATAL, "pg_local_sendauth: can't do setsockopt: %m");
 547                         }
 548 #endif
 549                         if (port->raddr.sa.sa_family == AF_UNIX)
 550                                 sendAuthRequest(port, AUTH_REQ_SCM_CREDS);
 551 #endif
 552                         status = authident(port);
 553                         break;
 554
 555                 case uaMD5:
 556                         sendAuthRequest(port, AUTH_REQ_MD5);
 557                         status = recv_and_check_password_packet(port);
 558                         break;
 559
 560                 case uaCrypt:
 561                         sendAuthRequest(port, AUTH_REQ_CRYPT);
 562                         status = recv_and_check_password_packet(port);
 563                         break;
 564
 565                 case uaPassword:
 566                         sendAuthRequest(port, AUTH_REQ_PASSWORD);
 567                         status = recv_and_check_password_packet(port);
 568                         break;
 569
 570 #ifdef USE_PAM
 571                 case uaPAM:
 572                         pam_port_cludge = port;
 573                         status = CheckPAMAuth(port, port->user, "");
 574                         break;
 575 #endif   /* USE_PAM */
 576
 577                 case uaTrust:
 578                         status = STATUS_OK;
 579                         break;
 580         }
 581
 582         if (status == STATUS_OK)
 583                 sendAuthRequest(port, AUTH_REQ_OK);
 584         else
 585                 auth_failed(port, status);
 586 }
 587
 588
 589 /*
 590  * Send an authentication request packet to the frontend.
 591  */
 592 static void
 593 sendAuthRequest(Port *port, AuthRequest areq)
 594 {
 595         StringInfoData buf;
 596
 597         pq_beginmessage(&buf);
 598         pq_sendbyte(&buf, 'R');
 599         pq_sendint(&buf, (int32) areq, sizeof(int32));
 600
 601         /* Add the salt for encrypted passwords. */
 602         if (areq == AUTH_REQ_MD5)
 603                 pq_sendbytes(&buf, port->md5Salt, 4);
 604         else if (areq == AUTH_REQ_CRYPT)
 605                 pq_sendbytes(&buf, port->cryptSalt, 2);
 606
 607         pq_endmessage(&buf);
 608
 609         /*
 610          * Flush message so client will see it, except for AUTH_REQ_OK,
 611          * which need not be sent until we are ready for queries.
 612          */
 613         if (areq != AUTH_REQ_OK)
 614                 pq_flush();
 615 }
 616
 617
 618 #ifdef USE_PAM
 619
 620 /*
 621  * PAM conversation function
 622  */
 623
 624 static int
 625 pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg, struct pam_response ** resp, void *appdata_ptr)
 626 {
 627         StringInfoData buf;
 628         int32           len;
 629
 630         if (num_msg != 1 || msg[0]->msg_style != PAM_PROMPT_ECHO_OFF)
 631         {
 632                 switch (msg[0]->msg_style)
 633                 {
 634                         case PAM_ERROR_MSG:
 635                                 elog(LOG, "pam_passwd_conv_proc: Error from underlying PAM layer: '%s'",
 636                                          msg[0]->msg);
 637                                 return PAM_CONV_ERR;
 638                         default:
 639                                 elog(LOG, "pam_passwd_conv_proc: Unexpected PAM conversation %d/'%s'",
 640                                          msg[0]->msg_style, msg[0]->msg);
 641                                 return PAM_CONV_ERR;
 642                 }
 643         }
 644
 645         if (!appdata_ptr)
 646         {
 647                 /*
 648                  * Workaround for Solaris 2.6 where the PAM library is broken and
 649                  * does not pass appdata_ptr to the conversation routine
 650                  */
 651                 appdata_ptr = pam_passwd;
 652         }
 653
 654         /*
 655          * Password wasn't passed to PAM the first time around - let's go ask
 656          * the client to send a password, which we then stuff into PAM.
 657          */
 658         if (strlen(appdata_ptr) == 0)
 659         {
 660                 sendAuthRequest(pam_port_cludge, AUTH_REQ_PASSWORD);
 661                 if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
 662                 {
 663                         return PAM_CONV_ERR;    /* client didn't want to send password */
 664                 }
 665
 666                 initStringInfo(&buf);
 667                 pq_getstr(&buf);
 668
 669                 /* Do not echo failed password to logs, for security. */
 670                 elog(DEBUG5, "received PAM packet");
 671
 672                 if (strlen(buf.data) == 0)
 673                 {
 674                         elog(LOG, "pam_passwd_conv_proc: no password");
 675                         return PAM_CONV_ERR;
 676                 }
 677                 appdata_ptr = buf.data;
 678         }
 679
 680         /*
 681          * Explicitly not using palloc here - PAM will free this memory in
 682          * pam_end()
 683          */
 684         *resp = calloc(num_msg, sizeof(struct pam_response));
 685         if (!*resp)
 686         {
 687                 elog(LOG, "pam_passwd_conv_proc: Out of memory!");
 688                 if (buf.data)
 689                         pfree(buf.data);
 690                 return PAM_CONV_ERR;
 691         }
 692
 693         (*resp)[0].resp = strdup((char *) appdata_ptr);
 694         (*resp)[0].resp_retcode = 0;
 695
 696         return ((*resp)[0].resp ? PAM_SUCCESS : PAM_CONV_ERR);
 697 }
 698
 699
 700 /*
 701  * Check authentication against PAM.
 702  */
 703 static int
 704 CheckPAMAuth(Port *port, char *user, char *password)
 705 {
 706         int                     retval;
 707         pam_handle_t *pamh = NULL;
 708
 709         /*
 710          * Apparently, Solaris 2.6 is broken, and needs ugly static variable
 711          * workaround
 712          */
 713         pam_passwd = password;
 714
 715         /*
 716          * Set the application data portion of the conversation struct This is
 717          * later used inside the PAM conversation to pass the password to the
 718          * authentication module.
 719          */
 720         pam_passw_conv.appdata_ptr = (char *) password;         /* from password above,
 721                                                                                                                  * not allocated */
 722
 723         /* Optionally, one can set the service name in pg_hba.conf */
 724         if (port->auth_arg[0] == '\0')
 725                 retval = pam_start(PGSQL_PAM_SERVICE, "pgsql@", &pam_passw_conv, &pamh);
 726         else
 727                 retval = pam_start(port->auth_arg, "pgsql@", &pam_passw_conv, &pamh);
 728
 729         if (retval != PAM_SUCCESS)
 730         {
 731                 elog(LOG, "CheckPAMAuth: Failed to create PAM authenticator: '%s'",
 732                          pam_strerror(pamh, retval));
 733                 pam_passwd = NULL;              /* Unset pam_passwd */
 734                 return STATUS_ERROR;
 735         }
 736
 737         retval = pam_set_item(pamh, PAM_USER, user);
 738
 739         if (retval != PAM_SUCCESS)
 740         {
 741                 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_USER) failed: '%s'",
 742                          pam_strerror(pamh, retval));
 743                 pam_passwd = NULL;              /* Unset pam_passwd */
 744                 return STATUS_ERROR;
 745         }
 746
 747         retval = pam_set_item(pamh, PAM_CONV, &pam_passw_conv);
 748
 749         if (retval != PAM_SUCCESS)
 750         {
 751                 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_CONV) failed: '%s'",
 752                          pam_strerror(pamh, retval));
 753                 pam_passwd = NULL;              /* Unset pam_passwd */
 754                 return STATUS_ERROR;
 755         }
 756
 757         retval = pam_authenticate(pamh, 0);
 758
 759         if (retval != PAM_SUCCESS)
 760         {
 761                 elog(LOG, "CheckPAMAuth: pam_authenticate failed: '%s'",
 762                          pam_strerror(pamh, retval));
 763                 pam_passwd = NULL;              /* Unset pam_passwd */
 764                 return STATUS_ERROR;
 765         }
 766
 767         retval = pam_acct_mgmt(pamh, 0);
 768
 769         if (retval != PAM_SUCCESS)
 770         {
 771                 elog(LOG, "CheckPAMAuth: pam_acct_mgmt failed: '%s'",
 772                          pam_strerror(pamh, retval));
 773                 pam_passwd = NULL;              /* Unset pam_passwd */
 774                 return STATUS_ERROR;
 775         }
 776
 777         retval = pam_end(pamh, retval);
 778
 779         if (retval != PAM_SUCCESS)
 780         {
 781                 elog(LOG, "CheckPAMAuth: Failed to release PAM authenticator: '%s'",
 782                          pam_strerror(pamh, retval));
 783         }
 784
 785         pam_passwd = NULL;              /* Unset pam_passwd */
 786
 787         return (retval == PAM_SUCCESS ? STATUS_OK : STATUS_ERROR);
 788 }
 789 #endif   /* USE_PAM */
 790
 791
 792 /*
 793  * Called when we have received the password packet.
 794  */
 795 static int
 796 recv_and_check_password_packet(Port *port)
 797 {
 798         StringInfoData buf;
 799         int32           len;
 800         int                     result;
 801
 802         if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
 803                 return STATUS_EOF;              /* client didn't want to send password */
 804
 805         initStringInfo(&buf);
 806         if (pq_getstr(&buf) == EOF) /* receive password */
 807         {
 808                 pfree(buf.data);
 809                 return STATUS_EOF;
 810         }
 811
 812         /* Do not echo failed password to logs, for security. */
 813         elog(DEBUG5, "received password packet");
 814
 815         result = md5_crypt_verify(port, port->user, buf.data);
 816
 817         pfree(buf.data);
 818         return result;
 819 }
 820
 821
 822 /*
 823  * Server demux routine for incoming authentication information for protocol
 824  * version 0.
 825  */
 826 static int
 827 old_be_recvauth(Port *port)
 828 {
 829         int                     status;
 830         MsgType         msgtype = (MsgType) port->proto;
 831
 832         /* Handle the authentication that's offered. */
 833         switch (msgtype)
 834         {
 835                 case STARTUP_KRB4_MSG:
 836                         status = map_old_to_new(port, uaKrb4, pg_krb4_recvauth(port));
 837                         break;
 838
 839                 case STARTUP_KRB5_MSG:
 840                         status = map_old_to_new(port, uaKrb5, pg_krb5_recvauth(port));
 841                         break;
 842
 843                 case STARTUP_MSG:
 844                         status = map_old_to_new(port, uaTrust, STATUS_OK);
 845                         break;
 846
 847                 case STARTUP_PASSWORD_MSG:
 848                         status = recv_and_check_passwordv0(port);
 849                         break;
 850
 851                 default:
 852                         elog(LOG, "Invalid startup message type: %u", msgtype);
 853
 854                         return STATUS_ERROR;
 855         }
 856
 857         return status;
 858 }
 859
 860
 861 /*
 862  * The old style authentication has been done.  Modify the result of this (eg.
 863  * allow the connection anyway, disallow it anyway, or use the result)
 864  * depending on what authentication we really want to use.
 865  */
 866 static int
 867 map_old_to_new(Port *port, UserAuth old, int status)
 868 {
 869         switch (port->auth_method)
 870         {
 871                 case uaMD5:
 872                 case uaCrypt:
 873                 case uaReject:
 874 #ifdef USE_PAM
 875                 case uaPAM:
 876 #endif   /* USE_PAM */
 877                         status = STATUS_ERROR;
 878                         break;
 879
 880                 case uaKrb4:
 881                         if (old != uaKrb4)
 882                                 status = STATUS_ERROR;
 883                         break;
 884
 885                 case uaKrb5:
 886                         if (old != uaKrb5)
 887                                 status = STATUS_ERROR;
 888                         break;
 889
 890                 case uaTrust:
 891                         status = STATUS_OK;
 892                         break;
 893
 894                 case uaIdent:
 895                         status = authident(port);
 896                         break;
 897
 898                 case uaPassword:
 899                         if (old != uaPassword)
 900                                 status = STATUS_ERROR;
 901
 902                         break;
 903         }
 904
 905         return status;
 906 }