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) 1996-2007, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL: pgsql/src/backend/libpq/auth.c,v 1.152 2007/07/12 14:43:20 mha Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15
  16 #include "postgres.h"
  17
  18 #include <sys/param.h>
  19 #include <sys/socket.h>
  20 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
  21 #include <sys/uio.h>
  22 #include <sys/ucred.h>
  23 #endif
  24 #include <netinet/in.h>
  25 #include <arpa/inet.h>
  26 #include <unistd.h>
  27
  28 #include "libpq/auth.h"
  29 #include "libpq/crypt.h"
  30 #include "libpq/ip.h"
  31 #include "libpq/libpq.h"
  32 #include "libpq/pqformat.h"
  33 #include "storage/ipc.h"
  34
  35
  36 static void sendAuthRequest(Port *port, AuthRequest areq);
  37 static void auth_failed(Port *port, int status);
  38 static char *recv_password_packet(Port *port);
  39 static int      recv_and_check_password_packet(Port *port);
  40
  41 char       *pg_krb_server_keyfile;
  42 char       *pg_krb_srvnam;
  43 bool            pg_krb_caseins_users;
  44 char       *pg_krb_server_hostname = NULL;
  45
  46 #ifdef USE_PAM
  47 #ifdef HAVE_PAM_PAM_APPL_H
  48 #include <pam/pam_appl.h>
  49 #endif
  50 #ifdef HAVE_SECURITY_PAM_APPL_H
  51 #include <security/pam_appl.h>
  52 #endif
  53
  54 #define PGSQL_PAM_SERVICE "postgresql"  /* Service name passed to PAM */
  55
  56 static int      CheckPAMAuth(Port *port, char *user, char *password);
  57 static int pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg,
  58                                          struct pam_response ** resp, void *appdata_ptr);
  59
  60 static struct pam_conv pam_passw_conv = {
  61         &pam_passwd_conv_proc,
  62         NULL
  63 };
  64
  65 static char *pam_passwd = NULL; /* Workaround for Solaris 2.6 brokenness */
  66 static Port *pam_port_cludge;   /* Workaround for passing "Port *port" into
  67                                                                  * pam_passwd_conv_proc */
  68 #endif   /* USE_PAM */
  69
  70 #ifdef USE_LDAP
  71 #ifndef WIN32
  72 /* We use a deprecated function to keep the codepath the same as win32. */
  73 #define LDAP_DEPRECATED 1
  74 #include <ldap.h>
  75 #else
  76 #include <winldap.h>
  77
  78 /* Correct header from the Platform SDK */
  79 typedef
  80 ULONG(*__ldap_start_tls_sA) (
  81                                                          IN PLDAP ExternalHandle,
  82                                                          OUT PULONG ServerReturnValue,
  83                                                          OUT LDAPMessage ** result,
  84                                                          IN PLDAPControlA * ServerControls,
  85                                                          IN PLDAPControlA * ClientControls
  86 );
  87 #endif
  88
  89 static int      CheckLDAPAuth(Port *port);
  90 #endif
  91
  92
  93 #ifdef KRB5
  94 /*----------------------------------------------------------------
  95  * MIT Kerberos authentication system - protocol version 5
  96  *----------------------------------------------------------------
  97  */
  98
  99 #include <krb5.h>
 100 /* Some old versions of Kerberos do not include <com_err.h> in <krb5.h> */
 101 #if !defined(__COM_ERR_H) && !defined(__COM_ERR_H__)
 102 #include <com_err.h>
 103 #endif
 104
 105 /*
 106  * pg_an_to_ln -- return the local name corresponding to an authentication
 107  *                                name
 108  *
 109  * XXX Assumes that the first aname component is the user name.  This is NOT
 110  *         necessarily so, since an aname can actually be something out of your
 111  *         worst X.400 nightmare, like
 112  *                ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
 113  *         Note that the MIT an_to_ln code does the same thing if you don't
 114  *         provide an aname mapping database...it may be a better idea to use
 115  *         krb5_an_to_ln, except that it punts if multiple components are found,
 116  *         and we can't afford to punt.
 117  */
 118 static char *
 119 pg_an_to_ln(char *aname)
 120 {
 121         char       *p;
 122
 123         if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
 124                 *p = '\0';
 125         return aname;
 126 }
 127
 128
 129 /*
 130  * Various krb5 state which is not connection specfic, and a flag to
 131  * indicate whether we have initialised it yet.
 132  */
 133 static int      pg_krb5_initialised;
 134 static krb5_context pg_krb5_context;
 135 static krb5_keytab pg_krb5_keytab;
 136 static krb5_principal pg_krb5_server;
 137
 138
 139 static int
 140 pg_krb5_init(void)
 141 {
 142         krb5_error_code retval;
 143         char       *khostname;
 144
 145         if (pg_krb5_initialised)
 146                 return STATUS_OK;
 147
 148         retval = krb5_init_context(&pg_krb5_context);
 149         if (retval)
 150         {
 151                 ereport(LOG,
 152                                 (errmsg("Kerberos initialization returned error %d",
 153                                                 retval)));
 154                 com_err("postgres", retval, "while initializing krb5");
 155                 return STATUS_ERROR;
 156         }
 157
 158         retval = krb5_kt_resolve(pg_krb5_context, pg_krb_server_keyfile, &pg_krb5_keytab);
 159         if (retval)
 160         {
 161                 ereport(LOG,
 162                                 (errmsg("Kerberos keytab resolving returned error %d",
 163                                                 retval)));
 164                 com_err("postgres", retval, "while resolving keytab file \"%s\"",
 165                                 pg_krb_server_keyfile);
 166                 krb5_free_context(pg_krb5_context);
 167                 return STATUS_ERROR;
 168         }
 169
 170         /*
 171          * If no hostname was specified, pg_krb_server_hostname is already NULL.
 172          * If it's set to blank, force it to NULL.
 173          */
 174         khostname = pg_krb_server_hostname;
 175         if (khostname && khostname[0] == '\0')
 176                 khostname = NULL;
 177
 178         retval = krb5_sname_to_principal(pg_krb5_context,
 179                                                                          khostname,
 180                                                                          pg_krb_srvnam,
 181                                                                          KRB5_NT_SRV_HST,
 182                                                                          &pg_krb5_server);
 183         if (retval)
 184         {
 185                 ereport(LOG,
 186                                 (errmsg("Kerberos sname_to_principal(\"%s\", \"%s\") returned error %d",
 187                  khostname ? khostname : "server hostname", pg_krb_srvnam, retval)));
 188                 com_err("postgres", retval,
 189                 "while getting server principal for server \"%s\" for service \"%s\"",
 190                                 khostname ? khostname : "server hostname", pg_krb_srvnam);
 191                 krb5_kt_close(pg_krb5_context, pg_krb5_keytab);
 192                 krb5_free_context(pg_krb5_context);
 193                 return STATUS_ERROR;
 194         }
 195
 196         pg_krb5_initialised = 1;
 197         return STATUS_OK;
 198 }
 199
 200
 201 /*
 202  * pg_krb5_recvauth -- server routine to receive authentication information
 203  *                                         from the client
 204  *
 205  * We still need to compare the username obtained from the client's setup
 206  * packet to the authenticated name.
 207  *
 208  * We have our own keytab file because postgres is unlikely to run as root,
 209  * and so cannot read the default keytab.
 210  */
 211 static int
 212 pg_krb5_recvauth(Port *port)
 213 {
 214         krb5_error_code retval;
 215         int                     ret;
 216         krb5_auth_context auth_context = NULL;
 217         krb5_ticket *ticket;
 218         char       *kusername;
 219
 220         if (get_role_line(port->user_name) == NULL)
 221                 return STATUS_ERROR;
 222
 223         ret = pg_krb5_init();
 224         if (ret != STATUS_OK)
 225                 return ret;
 226
 227         retval = krb5_recvauth(pg_krb5_context, &auth_context,
 228                                                    (krb5_pointer) & port->sock, pg_krb_srvnam,
 229                                                    pg_krb5_server, 0, pg_krb5_keytab, &ticket);
 230         if (retval)
 231         {
 232                 ereport(LOG,
 233                                 (errmsg("Kerberos recvauth returned error %d",
 234                                                 retval)));
 235                 com_err("postgres", retval, "from krb5_recvauth");
 236                 return STATUS_ERROR;
 237         }
 238
 239         /*
 240          * The "client" structure comes out of the ticket and is therefore
 241          * authenticated.  Use it to check the username obtained from the
 242          * postmaster startup packet.
 243          *
 244          * I have no idea why this is considered necessary.
 245          */
 246 #if defined(HAVE_KRB5_TICKET_ENC_PART2)
 247         retval = krb5_unparse_name(pg_krb5_context,
 248                                                            ticket->enc_part2->client, &kusername);
 249 #elif defined(HAVE_KRB5_TICKET_CLIENT)
 250         retval = krb5_unparse_name(pg_krb5_context,
 251                                                            ticket->client, &kusername);
 252 #else
 253 #error "bogus configuration"
 254 #endif
 255         if (retval)
 256         {
 257                 ereport(LOG,
 258                                 (errmsg("Kerberos unparse_name returned error %d",
 259                                                 retval)));
 260                 com_err("postgres", retval, "while unparsing client name");
 261                 krb5_free_ticket(pg_krb5_context, ticket);
 262                 krb5_auth_con_free(pg_krb5_context, auth_context);
 263                 return STATUS_ERROR;
 264         }
 265
 266         kusername = pg_an_to_ln(kusername);
 267         if (pg_krb_caseins_users)
 268                 ret = pg_strncasecmp(port->user_name, kusername, SM_DATABASE_USER);
 269         else
 270                 ret = strncmp(port->user_name, kusername, SM_DATABASE_USER);
 271         if (ret)
 272         {
 273                 ereport(LOG,
 274                                 (errmsg("unexpected Kerberos user name received from client (received \"%s\", expected \"%s\")",
 275                                                 port->user_name, kusername)));
 276                 ret = STATUS_ERROR;
 277         }
 278         else
 279                 ret = STATUS_OK;
 280
 281         krb5_free_ticket(pg_krb5_context, ticket);
 282         krb5_auth_con_free(pg_krb5_context, auth_context);
 283         free(kusername);
 284
 285         return ret;
 286 }
 287 #else
 288
 289 static int
 290 pg_krb5_recvauth(Port *port)
 291 {
 292         ereport(LOG,
 293                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 294                          errmsg("Kerberos 5 not implemented on this server")));
 295         return STATUS_ERROR;
 296 }
 297 #endif   /* KRB5 */
 298
 299 #ifdef ENABLE_GSS
 300 /*----------------------------------------------------------------
 301  * GSSAPI authentication system
 302  *----------------------------------------------------------------
 303  */
 304
 305 #if defined(HAVE_GSSAPI_H)
 306 #include <gssapi.h>
 307 #else
 308 #include <gssapi/gssapi.h>
 309 #endif
 310
 311 #if defined(WIN32) && !defined(WIN32_ONLY_COMPILER)
 312 /*
 313  * MIT Kerberos GSSAPI DLL doesn't properly export the symbols for MingW
 314  * that contain the OIDs required. Redefine here, values copied
 315  * from src/athena/auth/krb5/src/lib/gssapi/generic/gssapi_generic.c
 316  */
 317 static const gss_OID_desc GSS_C_NT_USER_NAME_desc =
 318  {10, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x02"};
 319 static GSS_DLLIMP gss_OID GSS_C_NT_USER_NAME = &GSS_C_NT_USER_NAME_desc;
 320 #endif
 321
 322
 323 static void
 324 pg_GSS_error(int severity, char *errmsg, OM_uint32 maj_stat, OM_uint32 min_stat)
 325 {
 326         gss_buffer_desc gmsg;
 327         OM_uint32               lmaj_s, lmin_s, msg_ctx;
 328         char                    msg_major[128],
 329                                         msg_minor[128];
 330
 331         /* Fetch major status message */
 332         msg_ctx = 0;
 333         lmaj_s = gss_display_status(&lmin_s, maj_stat, GSS_C_GSS_CODE,
 334                         GSS_C_NO_OID, &msg_ctx, &gmsg);
 335         strlcpy(msg_major, gmsg.value, sizeof(msg_major));
 336         gss_release_buffer(&lmin_s, &gmsg);
 337
 338         if (msg_ctx)
 339                 /* More than one message available.
 340                  * XXX: Should we loop and read all messages?
 341                  * (same below)
 342                  */
 343                 ereport(WARNING,
 344                                 (errmsg_internal("incomplete GSS error report")));
 345
 346         /* Fetch mechanism minor status message */
 347         msg_ctx = 0;
 348         lmaj_s = gss_display_status(&lmin_s, min_stat, GSS_C_MECH_CODE,
 349                         GSS_C_NO_OID, &msg_ctx, &gmsg);
 350         strlcpy(msg_minor, gmsg.value, sizeof(msg_minor));
 351         gss_release_buffer(&lmin_s, &gmsg);
 352
 353         if (msg_ctx)
 354                 ereport(WARNING,
 355                                 (errmsg_internal("incomplete GSS minor error report")));
 356
 357         /* errmsg_internal, since translation of the first part must be
 358          * done before calling this function anyway. */
 359         ereport(severity,
 360                         (errmsg_internal("%s", errmsg),
 361                          errdetail("%s: %s", msg_major, msg_minor)));
 362 }
 363
 364 static int
 365 pg_GSS_recvauth(Port *port)
 366 {
 367         OM_uint32               maj_stat, min_stat, lmin_s, gflags;
 368         char               *kt_path;
 369         int                             mtype;
 370         int                             ret;
 371         StringInfoData  buf;
 372         gss_buffer_desc gbuf;
 373
 374         if (pg_krb_server_keyfile && strlen(pg_krb_server_keyfile) > 0)
 375         {
 376                 /*
 377                  * Set default Kerberos keytab file for the Krb5 mechanism.
 378                  *
 379                  * setenv("KRB5_KTNAME", pg_krb_server_keyfile, 0);
 380                  *              except setenv() not always available.
 381                  */
 382                 if (!getenv("KRB5_KTNAME"))
 383                 {
 384                         kt_path = palloc(MAXPGPATH + 13);
 385                         snprintf(kt_path, MAXPGPATH + 13,
 386                                         "KRB5_KTNAME=%s", pg_krb_server_keyfile);
 387                         putenv(kt_path);
 388                 }
 389         }
 390
 391         /*
 392          * We accept any service principal that's present in our
 393          * keytab. This increases interoperability between kerberos
 394          * implementations that see for example case sensitivity
 395          * differently, while not really opening up any vector
 396          * of attack.
 397          */
 398         port->gss->cred = GSS_C_NO_CREDENTIAL;
 399
 400         /*
 401          * Initialize sequence with an empty context
 402          */
 403         port->gss->ctx = GSS_C_NO_CONTEXT;
 404
 405         /*
 406          * Loop through GSSAPI message exchange. This exchange can consist
 407          * of multiple messags sent in both directions. First message is always
 408          * from the client. All messages from client to server are password
 409          * packets (type 'p').
 410          */
 411         do
 412         {
 413                 mtype = pq_getbyte();
 414                 if (mtype != 'p')
 415                 {
 416                         /* Only log error if client didn't disconnect. */
 417                         if (mtype != EOF)
 418                                 ereport(COMMERROR,
 419                                                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
 420                                                  errmsg("expected GSS response, got message type %d",
 421                                                          mtype)));
 422                         return STATUS_ERROR;
 423                 }
 424
 425                 /* Get the actual GSS token */
 426                 initStringInfo(&buf);
 427                 if (pq_getmessage(&buf, 2000))
 428                 {
 429                         /* EOF - pq_getmessage already logged error */
 430                         pfree(buf.data);
 431                         return STATUS_ERROR;
 432                 }
 433
 434                 /* Map to GSSAPI style buffer */
 435                 gbuf.length = buf.len;
 436                 gbuf.value = buf.data;
 437
 438                 elog(DEBUG4, "Processing received GSS token of length %u",
 439                          gbuf.length);
 440
 441                 maj_stat = gss_accept_sec_context(
 442                                 &min_stat,
 443                                 &port->gss->ctx,
 444                                 port->gss->cred,
 445                                 &gbuf,
 446                                 GSS_C_NO_CHANNEL_BINDINGS,
 447                                 &port->gss->name,
 448                                 NULL,
 449                                 &port->gss->outbuf,
 450                                 &gflags,
 451                                 NULL,
 452                                 NULL);
 453
 454                 /* gbuf no longer used */
 455                 pfree(buf.data);
 456
 457                 elog(DEBUG5, "gss_accept_sec_context major: %i, "
 458                                          "minor: %i, outlen: %u, outflags: %x",
 459                                          maj_stat, min_stat,
 460                                          port->gss->outbuf.length, gflags);
 461
 462                 if (port->gss->outbuf.length != 0)
 463                 {
 464                         /*
 465                          * Negotiation generated data to be sent to the client.
 466                          */
 467                         elog(DEBUG4, "sending GSS response token of length %u",
 468                                  port->gss->outbuf.length);
 469
 470                         sendAuthRequest(port, AUTH_REQ_GSS_CONT);
 471                 }
 472
 473                 if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED)
 474                 {
 475                         OM_uint32       lmin_s;
 476                         gss_delete_sec_context(&lmin_s, &port->gss->ctx, GSS_C_NO_BUFFER);
 477                         pg_GSS_error(ERROR,
 478                                         gettext_noop("accepting GSS security context failed"),
 479                                         maj_stat, min_stat);
 480                 }
 481
 482                 if (maj_stat == GSS_S_CONTINUE_NEEDED)
 483                         elog(DEBUG4, "GSS continue needed");
 484
 485         } while (maj_stat == GSS_S_CONTINUE_NEEDED);
 486
 487         if (port->gss->cred != GSS_C_NO_CREDENTIAL)
 488         {
 489                 /*
 490                  * Release service principal credentials
 491                  */
 492                 gss_release_cred(&min_stat, port->gss->cred);
 493         }
 494
 495         /*
 496          * GSS_S_COMPLETE indicates that authentication is now complete.
 497          *
 498          * Get the name of the user that authenticated, and compare it to the
 499          * pg username that was specified for the connection.
 500          */
 501         maj_stat = gss_display_name(&min_stat, port->gss->name, &gbuf, NULL);
 502         if (maj_stat != GSS_S_COMPLETE)
 503                 pg_GSS_error(ERROR,
 504                                          gettext_noop("retreiving GSS user name failed"),
 505                                          maj_stat, min_stat);
 506
 507         /*
 508          * Compare the part of the username that comes before the @
 509          * sign only (ignore realm). The GSSAPI libraries won't have
 510          * authenticated the user if he's from an invalid realm.
 511          */
 512         if (strchr(gbuf.value, '@'))
 513         {
 514                 char *cp = strchr(gbuf.value, '@');
 515                 *cp = '\0';
 516         }
 517
 518         if (pg_krb_caseins_users)
 519                 ret = pg_strcasecmp(port->user_name, gbuf.value);
 520         else
 521                 ret = strcmp(port->user_name, gbuf.value);
 522
 523         if (ret)
 524         {
 525                 /* GSS name and PGUSER are not equivalent */
 526                 elog(DEBUG2,
 527                          "provided username (%s) and GSSAPI username (%s) don't match",
 528                          port->user_name, (char *)gbuf.value);
 529
 530                 gss_release_buffer(&lmin_s, &gbuf);
 531                 return STATUS_ERROR;
 532         }
 533
 534         gss_release_buffer(&lmin_s, &gbuf);
 535
 536         return STATUS_OK;
 537 }
 538
 539 #else   /* no ENABLE_GSS */
 540 static int
 541 pg_GSS_recvauth(Port *port)
 542 {
 543         ereport(LOG,
 544                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 545                          errmsg("GSSAPI not implemented on this server.")));
 546         return STATUS_ERROR;
 547 }
 548 #endif  /* ENABLE_GSS */
 549
 550
 551 /*
 552  * Tell the user the authentication failed, but not (much about) why.
 553  *
 554  * There is a tradeoff here between security concerns and making life
 555  * unnecessarily difficult for legitimate users.  We would not, for example,
 556  * want to report the password we were expecting to receive...
 557  * But it seems useful to report the username and authorization method
 558  * in use, and these are items that must be presumed known to an attacker
 559  * anyway.
 560  * Note that many sorts of failure report additional information in the
 561  * postmaster log, which we hope is only readable by good guys.
 562  */
 563 static void
 564 auth_failed(Port *port, int status)
 565 {
 566         const char *errstr;
 567
 568         /*
 569          * If we failed due to EOF from client, just quit; there's no point in
 570          * trying to send a message to the client, and not much point in logging
 571          * the failure in the postmaster log.  (Logging the failure might be
 572          * desirable, were it not for the fact that libpq closes the connection
 573          * unceremoniously if challenged for a password when it hasn't got one to
 574          * send.  We'll get a useless log entry for every psql connection under
 575          * password auth, even if it's perfectly successful, if we log STATUS_EOF
 576          * events.)
 577          */
 578         if (status == STATUS_EOF)
 579                 proc_exit(0);
 580
 581         switch (port->auth_method)
 582         {
 583                 case uaReject:
 584                         errstr = gettext_noop("authentication failed for user \"%s\": host rejected");
 585                         break;
 586                 case uaKrb5:
 587                         errstr = gettext_noop("Kerberos 5 authentication failed for user \"%s\"");
 588                         break;
 589                 case uaGSS:
 590                         errstr = gettext_noop("GSSAPI authentication failed for user \"%s\"");
 591                         break;
 592                 case uaTrust:
 593                         errstr = gettext_noop("\"trust\" authentication failed for user \"%s\"");
 594                         break;
 595                 case uaIdent:
 596                         errstr = gettext_noop("Ident authentication failed for user \"%s\"");
 597                         break;
 598                 case uaMD5:
 599                 case uaCrypt:
 600                 case uaPassword:
 601                         errstr = gettext_noop("password authentication failed for user \"%s\"");
 602                         break;
 603 #ifdef USE_PAM
 604                 case uaPAM:
 605                         errstr = gettext_noop("PAM authentication failed for user \"%s\"");
 606                         break;
 607 #endif   /* USE_PAM */
 608 #ifdef USE_LDAP
 609                 case uaLDAP:
 610                         errstr = gettext_noop("LDAP authentication failed for user \"%s\"");
 611                         break;
 612 #endif   /* USE_LDAP */
 613                 default:
 614                         errstr = gettext_noop("authentication failed for user \"%s\": invalid authentication method");
 615                         break;
 616         }
 617
 618         ereport(FATAL,
 619                         (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
 620                          errmsg(errstr, port->user_name)));
 621         /* doesn't return */
 622 }
 623
 624
 625 /*
 626  * Client authentication starts here.  If there is an error, this
 627  * function does not return and the backend process is terminated.
 628  */
 629 void
 630 ClientAuthentication(Port *port)
 631 {
 632         int                     status = STATUS_ERROR;
 633
 634         /*
 635          * Get the authentication method to use for this frontend/database
 636          * combination.  Note: a failure return indicates a problem with the hba
 637          * config file, not with the request.  hba.c should have dropped an error
 638          * message into the postmaster logfile if it failed.
 639          */
 640         if (hba_getauthmethod(port) != STATUS_OK)
 641                 ereport(FATAL,
 642                                 (errcode(ERRCODE_CONFIG_FILE_ERROR),
 643                                  errmsg("missing or erroneous pg_hba.conf file"),
 644                                  errhint("See server log for details.")));
 645
 646         switch (port->auth_method)
 647         {
 648                 case uaReject:
 649
 650                         /*
 651                          * This could have come from an explicit "reject" entry in
 652                          * pg_hba.conf, but more likely it means there was no matching
 653                          * entry.  Take pity on the poor user and issue a helpful error
 654                          * message.  NOTE: this is not a security breach, because all the
 655                          * info reported here is known at the frontend and must be assumed
 656                          * known to bad guys. We're merely helping out the less clueful
 657                          * good guys.
 658                          */
 659                         {
 660                                 char            hostinfo[NI_MAXHOST];
 661
 662                                 pg_getnameinfo_all(&port->raddr.addr, port->raddr.salen,
 663                                                                    hostinfo, sizeof(hostinfo),
 664                                                                    NULL, 0,
 665                                                                    NI_NUMERICHOST);
 666
 667 #ifdef USE_SSL
 668                                 ereport(FATAL,
 669                                                 (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
 670                                                  errmsg("no pg_hba.conf entry for host \"%s\", user \"%s\", database \"%s\", %s",
 671                                                           hostinfo, port->user_name, port->database_name,
 672                                                                 port->ssl ? _("SSL on") : _("SSL off"))));
 673 #else
 674                                 ereport(FATAL,
 675                                                 (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
 676                                                  errmsg("no pg_hba.conf entry for host \"%s\", user \"%s\", database \"%s\"",
 677                                                    hostinfo, port->user_name, port->database_name)));
 678 #endif
 679                                 break;
 680                         }
 681
 682                 case uaKrb5:
 683                         sendAuthRequest(port, AUTH_REQ_KRB5);
 684                         status = pg_krb5_recvauth(port);
 685                         break;
 686
 687                 case uaGSS:
 688                         sendAuthRequest(port, AUTH_REQ_GSS);
 689                         status = pg_GSS_recvauth(port);
 690                         break;
 691
 692                 case uaIdent:
 693
 694                         /*
 695                          * If we are doing ident on unix-domain sockets, use SCM_CREDS
 696                          * only if it is defined and SO_PEERCRED isn't.
 697                          */
 698 #if !defined(HAVE_GETPEEREID) && !defined(SO_PEERCRED) && \
 699         (defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || \
 700          (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS)))
 701                         if (port->raddr.addr.ss_family == AF_UNIX)
 702                         {
 703 #if defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
 704
 705                                 /*
 706                                  * Receive credentials on next message receipt, BSD/OS,
 707                                  * NetBSD. We need to set this before the client sends the
 708                                  * next packet.
 709                                  */
 710                                 int                     on = 1;
 711
 712                                 if (setsockopt(port->sock, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
 713                                         ereport(FATAL,
 714                                                         (errcode_for_socket_access(),
 715                                            errmsg("could not enable credential reception: %m")));
 716 #endif
 717
 718                                 sendAuthRequest(port, AUTH_REQ_SCM_CREDS);
 719                         }
 720 #endif
 721                         status = authident(port);
 722                         break;
 723
 724                 case uaMD5:
 725                         sendAuthRequest(port, AUTH_REQ_MD5);
 726                         status = recv_and_check_password_packet(port);
 727                         break;
 728
 729                 case uaCrypt:
 730                         sendAuthRequest(port, AUTH_REQ_CRYPT);
 731                         status = recv_and_check_password_packet(port);
 732                         break;
 733
 734                 case uaPassword:
 735                         sendAuthRequest(port, AUTH_REQ_PASSWORD);
 736                         status = recv_and_check_password_packet(port);
 737                         break;
 738
 739 #ifdef USE_PAM
 740                 case uaPAM:
 741                         pam_port_cludge = port;
 742                         status = CheckPAMAuth(port, port->user_name, "");
 743                         break;
 744 #endif   /* USE_PAM */
 745
 746 #ifdef USE_LDAP
 747                 case uaLDAP:
 748                         status = CheckLDAPAuth(port);
 749                         break;
 750 #endif
 751
 752                 case uaTrust:
 753                         status = STATUS_OK;
 754                         break;
 755         }
 756
 757         if (status == STATUS_OK)
 758                 sendAuthRequest(port, AUTH_REQ_OK);
 759         else
 760                 auth_failed(port, status);
 761 }
 762
 763
 764 /*
 765  * Send an authentication request packet to the frontend.
 766  */
 767 static void
 768 sendAuthRequest(Port *port, AuthRequest areq)
 769 {
 770         StringInfoData buf;
 771
 772         pq_beginmessage(&buf, 'R');
 773         pq_sendint(&buf, (int32) areq, sizeof(int32));
 774
 775         /* Add the salt for encrypted passwords. */
 776         if (areq == AUTH_REQ_MD5)
 777                 pq_sendbytes(&buf, port->md5Salt, 4);
 778         else if (areq == AUTH_REQ_CRYPT)
 779                 pq_sendbytes(&buf, port->cryptSalt, 2);
 780
 781 #ifdef ENABLE_GSS
 782         /* Add the authentication data for the next step of
 783          * the GSSAPI negotiation. */
 784         else if (areq == AUTH_REQ_GSS_CONT)
 785         {
 786                 if (port->gss->outbuf.length > 0)
 787                 {
 788                         OM_uint32       lmin_s;
 789
 790                         elog(DEBUG4, "sending GSS token of length %u",
 791                                  port->gss->outbuf.length);
 792
 793                         pq_sendbytes(&buf, port->gss->outbuf.value, port->gss->outbuf.length);
 794                         gss_release_buffer(&lmin_s, &port->gss->outbuf);
 795                 }
 796         }
 797 #endif
 798
 799         pq_endmessage(&buf);
 800
 801         /*
 802          * Flush message so client will see it, except for AUTH_REQ_OK, which need
 803          * not be sent until we are ready for queries.
 804          */
 805         if (areq != AUTH_REQ_OK)
 806                 pq_flush();
 807 }
 808
 809
 810 #ifdef USE_PAM
 811
 812 /*
 813  * PAM conversation function
 814  */
 815
 816 static int
 817 pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg,
 818                                          struct pam_response ** resp, void *appdata_ptr)
 819 {
 820         if (num_msg != 1 || msg[0]->msg_style != PAM_PROMPT_ECHO_OFF)
 821         {
 822                 switch (msg[0]->msg_style)
 823                 {
 824                         case PAM_ERROR_MSG:
 825                                 ereport(LOG,
 826                                                 (errmsg("error from underlying PAM layer: %s",
 827                                                                 msg[0]->msg)));
 828                                 return PAM_CONV_ERR;
 829                         default:
 830                                 ereport(LOG,
 831                                                 (errmsg("unsupported PAM conversation %d/%s",
 832                                                                 msg[0]->msg_style, msg[0]->msg)));
 833                                 return PAM_CONV_ERR;
 834                 }
 835         }
 836
 837         if (!appdata_ptr)
 838         {
 839                 /*
 840                  * Workaround for Solaris 2.6 where the PAM library is broken and does
 841                  * not pass appdata_ptr to the conversation routine
 842                  */
 843                 appdata_ptr = pam_passwd;
 844         }
 845
 846         /*
 847          * Password wasn't passed to PAM the first time around - let's go ask the
 848          * client to send a password, which we then stuff into PAM.
 849          */
 850         if (strlen(appdata_ptr) == 0)
 851         {
 852                 char       *passwd;
 853
 854                 sendAuthRequest(pam_port_cludge, AUTH_REQ_PASSWORD);
 855                 passwd = recv_password_packet(pam_port_cludge);
 856
 857                 if (passwd == NULL)
 858                         return PAM_CONV_ERR;    /* client didn't want to send password */
 859
 860                 if (strlen(passwd) == 0)
 861                 {
 862                         ereport(LOG,
 863                                         (errmsg("empty password returned by client")));
 864                         return PAM_CONV_ERR;
 865                 }
 866                 appdata_ptr = passwd;
 867         }
 868
 869         /*
 870          * Explicitly not using palloc here - PAM will free this memory in
 871          * pam_end()
 872          */
 873         *resp = calloc(num_msg, sizeof(struct pam_response));
 874         if (!*resp)
 875         {
 876                 ereport(LOG,
 877                                 (errcode(ERRCODE_OUT_OF_MEMORY),
 878                                  errmsg("out of memory")));
 879                 return PAM_CONV_ERR;
 880         }
 881
 882         (*resp)[0].resp = strdup((char *) appdata_ptr);
 883         (*resp)[0].resp_retcode = 0;
 884
 885         return ((*resp)[0].resp ? PAM_SUCCESS : PAM_CONV_ERR);
 886 }
 887
 888
 889 /*
 890  * Check authentication against PAM.
 891  */
 892 static int
 893 CheckPAMAuth(Port *port, char *user, char *password)
 894 {
 895         int                     retval;
 896         pam_handle_t *pamh = NULL;
 897
 898         /*
 899          * Apparently, Solaris 2.6 is broken, and needs ugly static variable
 900          * workaround
 901          */
 902         pam_passwd = password;
 903
 904         /*
 905          * Set the application data portion of the conversation struct This is
 906          * later used inside the PAM conversation to pass the password to the
 907          * authentication module.
 908          */
 909         pam_passw_conv.appdata_ptr = (char *) password;         /* from password above,
 910                                                                                                                  * not allocated */
 911
 912         /* Optionally, one can set the service name in pg_hba.conf */
 913         if (port->auth_arg && port->auth_arg[0] != '\0')
 914                 retval = pam_start(port->auth_arg, "pgsql@",
 915                                                    &pam_passw_conv, &pamh);
 916         else
 917                 retval = pam_start(PGSQL_PAM_SERVICE, "pgsql@",
 918                                                    &pam_passw_conv, &pamh);
 919
 920         if (retval != PAM_SUCCESS)
 921         {
 922                 ereport(LOG,
 923                                 (errmsg("could not create PAM authenticator: %s",
 924                                                 pam_strerror(pamh, retval))));
 925                 pam_passwd = NULL;              /* Unset pam_passwd */
 926                 return STATUS_ERROR;
 927         }
 928
 929         retval = pam_set_item(pamh, PAM_USER, user);
 930
 931         if (retval != PAM_SUCCESS)
 932         {
 933                 ereport(LOG,
 934                                 (errmsg("pam_set_item(PAM_USER) failed: %s",
 935                                                 pam_strerror(pamh, retval))));
 936                 pam_passwd = NULL;              /* Unset pam_passwd */
 937                 return STATUS_ERROR;
 938         }
 939
 940         retval = pam_set_item(pamh, PAM_CONV, &pam_passw_conv);
 941
 942         if (retval != PAM_SUCCESS)
 943         {
 944                 ereport(LOG,
 945                                 (errmsg("pam_set_item(PAM_CONV) failed: %s",
 946                                                 pam_strerror(pamh, retval))));
 947                 pam_passwd = NULL;              /* Unset pam_passwd */
 948                 return STATUS_ERROR;
 949         }
 950
 951         retval = pam_authenticate(pamh, 0);
 952
 953         if (retval != PAM_SUCCESS)
 954         {
 955                 ereport(LOG,
 956                                 (errmsg("pam_authenticate failed: %s",
 957                                                 pam_strerror(pamh, retval))));
 958                 pam_passwd = NULL;              /* Unset pam_passwd */
 959                 return STATUS_ERROR;
 960         }
 961
 962         retval = pam_acct_mgmt(pamh, 0);
 963
 964         if (retval != PAM_SUCCESS)
 965         {
 966                 ereport(LOG,
 967                                 (errmsg("pam_acct_mgmt failed: %s",
 968                                                 pam_strerror(pamh, retval))));
 969                 pam_passwd = NULL;              /* Unset pam_passwd */
 970                 return STATUS_ERROR;
 971         }
 972
 973         retval = pam_end(pamh, retval);
 974
 975         if (retval != PAM_SUCCESS)
 976         {
 977                 ereport(LOG,
 978                                 (errmsg("could not release PAM authenticator: %s",
 979                                                 pam_strerror(pamh, retval))));
 980         }
 981
 982         pam_passwd = NULL;                      /* Unset pam_passwd */
 983
 984         return (retval == PAM_SUCCESS ? STATUS_OK : STATUS_ERROR);
 985 }
 986 #endif   /* USE_PAM */
 987
 988
 989 #ifdef USE_LDAP
 990
 991 static int
 992 CheckLDAPAuth(Port *port)
 993 {
 994         char       *passwd;
 995         char            server[128];
 996         char            basedn[128];
 997         char            prefix[128];
 998         char            suffix[128];
 999         LDAP       *ldap;
1000         bool            ssl = false;
1001         int                     r;
1002         int                     ldapversion = LDAP_VERSION3;
1003         int                     ldapport = LDAP_PORT;
1004         char            fulluser[NAMEDATALEN + 256 + 1];
1005
1006         if (!port->auth_arg || port->auth_arg[0] == '\0')
1007         {
1008                 ereport(LOG,
1009                                 (errmsg("LDAP configuration URL not specified")));
1010                 return STATUS_ERROR;
1011         }
1012
1013         /*
1014          * Crack the LDAP url. We do a very trivial parse..
1015          * ldap[s]://<server>[:<port>]/<basedn>[;prefix[;suffix]]
1016          */
1017
1018         server[0] = '\0';
1019         basedn[0] = '\0';
1020         prefix[0] = '\0';
1021         suffix[0] = '\0';
1022
1023         /* ldap, including port number */
1024         r = sscanf(port->auth_arg,
1025                            "ldap://%127[^:]:%i/%127[^;];%127[^;];%127s",
1026                            server, &ldapport, basedn, prefix, suffix);
1027         if (r < 3)
1028         {
1029                 /* ldaps, including port number */
1030                 r = sscanf(port->auth_arg,
1031                                    "ldaps://%127[^:]:%i/%127[^;];%127[^;];%127s",
1032                                    server, &ldapport, basedn, prefix, suffix);
1033                 if (r >= 3)
1034                         ssl = true;
1035         }
1036         if (r < 3)
1037         {
1038                 /* ldap, no port number */
1039                 r = sscanf(port->auth_arg,
1040                                    "ldap://%127[^/]/%127[^;];%127[^;];%127s",
1041                                    server, basedn, prefix, suffix);
1042         }
1043         if (r < 2)
1044         {
1045                 /* ldaps, no port number */
1046                 r = sscanf(port->auth_arg,
1047                                    "ldaps://%127[^/]/%127[^;];%127[^;];%127s",
1048                                    server, basedn, prefix, suffix);
1049                 if (r >= 2)
1050                         ssl = true;
1051         }
1052         if (r < 2)
1053         {
1054                 ereport(LOG,
1055                                 (errmsg("invalid LDAP URL: \"%s\"",
1056                                                 port->auth_arg)));
1057                 return STATUS_ERROR;
1058         }
1059
1060         sendAuthRequest(port, AUTH_REQ_PASSWORD);
1061
1062         passwd = recv_password_packet(port);
1063         if (passwd == NULL)
1064                 return STATUS_EOF;              /* client wouldn't send password */
1065
1066         ldap = ldap_init(server, ldapport);
1067         if (!ldap)
1068         {
1069 #ifndef WIN32
1070                 ereport(LOG,
1071                                 (errmsg("could not initialize LDAP: error code %d",
1072                                                 errno)));
1073 #else
1074                 ereport(LOG,
1075                                 (errmsg("could not initialize LDAP: error code %d",
1076                                                 (int) LdapGetLastError())));
1077 #endif
1078                 return STATUS_ERROR;
1079         }
1080
1081         if ((r = ldap_set_option(ldap, LDAP_OPT_PROTOCOL_VERSION, &ldapversion)) != LDAP_SUCCESS)
1082         {
1083                 ldap_unbind(ldap);
1084                 ereport(LOG,
1085                                 (errmsg("could not set LDAP protocol version: error code %d", r)));
1086                 return STATUS_ERROR;
1087         }
1088
1089         if (ssl)
1090         {
1091 #ifndef WIN32
1092                 if ((r = ldap_start_tls_s(ldap, NULL, NULL)) != LDAP_SUCCESS)
1093 #else
1094                 static __ldap_start_tls_sA _ldap_start_tls_sA = NULL;
1095
1096                 if (_ldap_start_tls_sA == NULL)
1097                 {
1098                         /*
1099                          * Need to load this function dynamically because it does not
1100                          * exist on Windows 2000, and causes a load error for the whole
1101                          * exe if referenced.
1102                          */
1103                         HANDLE          ldaphandle;
1104
1105                         ldaphandle = LoadLibrary("WLDAP32.DLL");
1106                         if (ldaphandle == NULL)
1107                         {
1108                                 /*
1109                                  * should never happen since we import other files from
1110                                  * wldap32, but check anyway
1111                                  */
1112                                 ldap_unbind(ldap);
1113                                 ereport(LOG,
1114                                                 (errmsg("could not load wldap32.dll")));
1115                                 return STATUS_ERROR;
1116                         }
1117                         _ldap_start_tls_sA = (__ldap_start_tls_sA) GetProcAddress(ldaphandle, "ldap_start_tls_sA");
1118                         if (_ldap_start_tls_sA == NULL)
1119                         {
1120                                 ldap_unbind(ldap);
1121                                 ereport(LOG,
1122                                                 (errmsg("could not load function _ldap_start_tls_sA in wldap32.dll"),
1123                                                  errdetail("LDAP over SSL is not supported on this platform.")));
1124                                 return STATUS_ERROR;
1125                         }
1126
1127                         /*
1128                          * Leak LDAP handle on purpose, because we need the library to stay
1129                          * open. This is ok because it will only ever be leaked once per
1130                          * process and is automatically cleaned up on process exit.
1131                          */
1132                 }
1133                 if ((r = _ldap_start_tls_sA(ldap, NULL, NULL, NULL, NULL)) != LDAP_SUCCESS)
1134 #endif
1135                 {
1136                         ldap_unbind(ldap);
1137                         ereport(LOG,
1138                                         (errmsg("could not start LDAP TLS session: error code %d", r)));
1139                         return STATUS_ERROR;
1140                 }
1141         }
1142
1143         snprintf(fulluser, sizeof(fulluser), "%s%s%s",
1144                          prefix, port->user_name, suffix);
1145         fulluser[sizeof(fulluser) - 1] = '\0';
1146
1147         r = ldap_simple_bind_s(ldap, fulluser, passwd);
1148         ldap_unbind(ldap);
1149
1150         if (r != LDAP_SUCCESS)
1151         {
1152                 ereport(LOG,
1153                                 (errmsg("LDAP login failed for user \"%s\" on server \"%s\": error code %d",
1154                                                 fulluser, server, r)));
1155                 return STATUS_ERROR;
1156         }
1157
1158         return STATUS_OK;
1159 }
1160 #endif   /* USE_LDAP */
1161
1162 /*
1163  * Collect password response packet from frontend.
1164  *
1165  * Returns NULL if couldn't get password, else palloc'd string.
1166  */
1167 static char *
1168 recv_password_packet(Port *port)
1169 {
1170         StringInfoData buf;
1171
1172         if (PG_PROTOCOL_MAJOR(port->proto) >= 3)
1173         {
1174                 /* Expect 'p' message type */
1175                 int                     mtype;
1176
1177                 mtype = pq_getbyte();
1178                 if (mtype != 'p')
1179                 {
1180                         /*
1181                          * If the client just disconnects without offering a password,
1182                          * don't make a log entry.  This is legal per protocol spec and in
1183                          * fact commonly done by psql, so complaining just clutters the
1184                          * log.
1185                          */
1186                         if (mtype != EOF)
1187                                 ereport(COMMERROR,
1188                                                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
1189                                         errmsg("expected password response, got message type %d",
1190                                                    mtype)));
1191                         return NULL;            /* EOF or bad message type */
1192                 }
1193         }
1194         else
1195         {
1196                 /* For pre-3.0 clients, avoid log entry if they just disconnect */
1197                 if (pq_peekbyte() == EOF)
1198                         return NULL;            /* EOF */
1199         }
1200
1201         initStringInfo(&buf);
1202         if (pq_getmessage(&buf, 1000))          /* receive password */
1203         {
1204                 /* EOF - pq_getmessage already logged a suitable message */
1205                 pfree(buf.data);
1206                 return NULL;
1207         }
1208
1209         /*
1210          * Apply sanity check: password packet length should agree with length of
1211          * contained string.  Note it is safe to use strlen here because
1212          * StringInfo is guaranteed to have an appended '\0'.
1213          */
1214         if (strlen(buf.data) + 1 != buf.len)
1215                 ereport(COMMERROR,
1216                                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
1217                                  errmsg("invalid password packet size")));
1218
1219         /* Do not echo password to logs, for security. */
1220         ereport(DEBUG5,
1221                         (errmsg("received password packet")));
1222
1223         /*
1224          * Return the received string.  Note we do not attempt to do any
1225          * character-set conversion on it; since we don't yet know the client's
1226          * encoding, there wouldn't be much point.
1227          */
1228         return buf.data;
1229 }
1230
1231
1232 /*
1233  * Called when we have sent an authorization request for a password.
1234  * Get the response and check it.
1235  */
1236 static int
1237 recv_and_check_password_packet(Port *port)
1238 {
1239         char       *passwd;
1240         int                     result;
1241
1242         passwd = recv_password_packet(port);
1243
1244         if (passwd == NULL)
1245                 return STATUS_EOF;              /* client wouldn't send password */
1246
1247         result = md5_crypt_verify(port, port->user_name, passwd);
1248
1249         pfree(passwd);
1250
1251         return result;
1252 }