1 /*-------------------------------------------------------------------------
4 * Routines to handle network authentication
6 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
11 * $PostgreSQL: pgsql/src/backend/libpq/auth.c,v 1.114 2003/12/20 18:24:52 tgl Exp $
13 *-------------------------------------------------------------------------
18 #include <sys/param.h>
19 #include <sys/socket.h>
20 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
22 #include <sys/ucred.h>
25 #include <netinet/in.h>
26 #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/pqcomm.h"
33 #include "libpq/pqformat.h"
34 #include "miscadmin.h"
35 #include "storage/ipc.h"
38 static void sendAuthRequest(Port *port, AuthRequest areq);
39 static void auth_failed(Port *port, int status);
40 static char *recv_password_packet(Port *port);
41 static int recv_and_check_password_packet(Port *port);
43 char *pg_krb_server_keyfile;
46 #ifdef HAVE_PAM_PAM_APPL_H
47 #include <pam/pam_appl.h>
49 #ifdef HAVE_SECURITY_PAM_APPL_H
50 #include <security/pam_appl.h>
53 #define PGSQL_PAM_SERVICE "postgresql" /* Service name passed to PAM */
55 static int CheckPAMAuth(Port *port, char *user, char *password);
56 static int pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg,
57 struct pam_response ** resp, void *appdata_ptr);
59 static struct pam_conv pam_passw_conv = {
60 &pam_passwd_conv_proc,
64 static char *pam_passwd = NULL; /* Workaround for Solaris 2.6 brokenness */
65 static Port *pam_port_cludge; /* Workaround for passing "Port *port"
66 * into pam_passwd_conv_proc */
70 /*----------------------------------------------------------------
71 * MIT Kerberos authentication system - protocol version 4
72 *----------------------------------------------------------------
78 * pg_krb4_recvauth -- server routine to receive authentication information
81 * Nothing unusual here, except that we compare the username obtained from
82 * the client's setup packet to the authenticated name. (We have to retain
83 * the name in the setup packet since we have to retain the ability to handle
84 * unauthenticated connections.)
87 pg_krb4_recvauth(Port *port)
89 long krbopts = 0; /* one-way authentication */
91 char instance[INST_SZ + 1],
92 version[KRB_SENDAUTH_VLEN + 1];
94 Key_schedule key_sched;
97 strcpy(instance, "*"); /* don't care, but arg gets expanded
99 status = krb_recvauth(krbopts,
107 pg_krb_server_keyfile,
110 if (status != KSUCCESS)
113 (errmsg("Kerberos error: %s", krb_err_txt[status])));
116 if (strncmp(version, PG_KRB4_VERSION, KRB_SENDAUTH_VLEN) != 0)
119 (errmsg("unexpected Kerberos protocol version received from client (received \"%s\", expected \"%s\")",
120 version, PG_KRB4_VERSION)));
123 if (strncmp(port->user_name, auth_data.pname, SM_DATABASE_USER) != 0)
126 (errmsg("unexpected Kerberos user name received from client (received \"%s\", expected \"%s\")",
127 port->user_name, auth_data.pname)));
136 pg_krb4_recvauth(Port *port)
139 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
140 errmsg("Kerberos 4 not implemented on this server")));
147 /*----------------------------------------------------------------
148 * MIT Kerberos authentication system - protocol version 5
149 *----------------------------------------------------------------
156 * pg_an_to_ln -- return the local name corresponding to an authentication
159 * XXX Assumes that the first aname component is the user name. This is NOT
160 * necessarily so, since an aname can actually be something out of your
161 * worst X.400 nightmare, like
162 * ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
163 * Note that the MIT an_to_ln code does the same thing if you don't
164 * provide an aname mapping database...it may be a better idea to use
165 * krb5_an_to_ln, except that it punts if multiple components are found,
166 * and we can't afford to punt.
169 pg_an_to_ln(char *aname)
173 if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
180 * Various krb5 state which is not connection specfic, and a flag to
181 * indicate whether we have initialised it yet.
183 static int pg_krb5_initialised;
184 static krb5_context pg_krb5_context;
185 static krb5_keytab pg_krb5_keytab;
186 static krb5_principal pg_krb5_server;
192 krb5_error_code retval;
194 if (pg_krb5_initialised)
197 retval = krb5_init_context(&pg_krb5_context);
201 (errmsg("Kerberos initialization returned error %d",
203 com_err("postgres", retval, "while initializing krb5");
207 retval = krb5_kt_resolve(pg_krb5_context, pg_krb_server_keyfile, &pg_krb5_keytab);
211 (errmsg("Kerberos keytab resolving returned error %d",
213 com_err("postgres", retval, "while resolving keytab file \"%s\"",
214 pg_krb_server_keyfile);
215 krb5_free_context(pg_krb5_context);
219 retval = krb5_sname_to_principal(pg_krb5_context, NULL, PG_KRB_SRVNAM,
220 KRB5_NT_SRV_HST, &pg_krb5_server);
224 (errmsg("Kerberos sname_to_principal(\"%s\") returned error %d",
225 PG_KRB_SRVNAM, retval)));
226 com_err("postgres", retval,
227 "while getting server principal for service \"%s\"",
229 krb5_kt_close(pg_krb5_context, pg_krb5_keytab);
230 krb5_free_context(pg_krb5_context);
234 pg_krb5_initialised = 1;
240 * pg_krb5_recvauth -- server routine to receive authentication information
243 * We still need to compare the username obtained from the client's setup
244 * packet to the authenticated name, as described in pg_krb4_recvauth. This
245 * is a bit more problematic in v5, as described above in pg_an_to_ln.
247 * We have our own keytab file because postgres is unlikely to run as root,
248 * and so cannot read the default keytab.
251 pg_krb5_recvauth(Port *port)
253 krb5_error_code retval;
255 krb5_auth_context auth_context = NULL;
259 ret = pg_krb5_init();
260 if (ret != STATUS_OK)
263 retval = krb5_recvauth(pg_krb5_context, &auth_context,
264 (krb5_pointer) & port->sock, PG_KRB_SRVNAM,
265 pg_krb5_server, 0, pg_krb5_keytab, &ticket);
269 (errmsg("Kerberos recvauth returned error %d",
271 com_err("postgres", retval, "from krb5_recvauth");
276 * The "client" structure comes out of the ticket and is therefore
277 * authenticated. Use it to check the username obtained from the
278 * postmaster startup packet.
280 * I have no idea why this is considered necessary.
282 #if defined(HAVE_KRB5_TICKET_ENC_PART2)
283 retval = krb5_unparse_name(pg_krb5_context,
284 ticket->enc_part2->client, &kusername);
285 #elif defined(HAVE_KRB5_TICKET_CLIENT)
286 retval = krb5_unparse_name(pg_krb5_context,
287 ticket->client, &kusername);
289 #error "bogus configuration"
294 (errmsg("Kerberos unparse_name returned error %d",
296 com_err("postgres", retval, "while unparsing client name");
297 krb5_free_ticket(pg_krb5_context, ticket);
298 krb5_auth_con_free(pg_krb5_context, auth_context);
302 kusername = pg_an_to_ln(kusername);
303 if (strncmp(port->user_name, kusername, SM_DATABASE_USER))
306 (errmsg("unexpected Kerberos user name received from client (received \"%s\", expected \"%s\")",
307 port->user_name, kusername)));
313 krb5_free_ticket(pg_krb5_context, ticket);
314 krb5_auth_con_free(pg_krb5_context, auth_context);
323 pg_krb5_recvauth(Port *port)
326 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
327 errmsg("Kerberos 5 not implemented on this server")));
334 * Tell the user the authentication failed, but not (much about) why.
336 * There is a tradeoff here between security concerns and making life
337 * unnecessarily difficult for legitimate users. We would not, for example,
338 * want to report the password we were expecting to receive...
339 * But it seems useful to report the username and authorization method
340 * in use, and these are items that must be presumed known to an attacker
342 * Note that many sorts of failure report additional information in the
343 * postmaster log, which we hope is only readable by good guys.
346 auth_failed(Port *port, int status)
348 const char *authmethod = "Unknown auth method:";
351 * If we failed due to EOF from client, just quit; there's no point in
352 * trying to send a message to the client, and not much point in
353 * logging the failure in the postmaster log. (Logging the failure
354 * might be desirable, were it not for the fact that libpq closes the
355 * connection unceremoniously if challenged for a password when it
356 * hasn't got one to send. We'll get a useless log entry for every
357 * psql connection under password auth, even if it's perfectly
358 * successful, if we log STATUS_EOF events.)
360 if (status == STATUS_EOF)
363 switch (port->auth_method)
366 authmethod = "Rejected host:";
369 authmethod = "Kerberos4";
372 authmethod = "Kerberos5";
375 authmethod = "Trusted";
378 authmethod = "IDENT";
383 authmethod = "Password";
393 (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
394 errmsg("%s authentication failed for user \"%s\"",
395 authmethod, port->user_name)));
401 * Client authentication starts here. If there is an error, this
402 * function does not return and the backend process is terminated.
405 ClientAuthentication(Port *port)
407 int status = STATUS_ERROR;
410 * Get the authentication method to use for this frontend/database
411 * combination. Note: a failure return indicates a problem with the
412 * hba config file, not with the request. hba.c should have dropped
413 * an error message into the postmaster logfile if it failed.
415 if (hba_getauthmethod(port) != STATUS_OK)
417 (errcode(ERRCODE_CONFIG_FILE_ERROR),
418 errmsg("missing or erroneous pg_hba.conf file"),
419 errhint("See server log for details.")));
421 switch (port->auth_method)
426 * This could have come from an explicit "reject" entry in
427 * pg_hba.conf, but more likely it means there was no matching
428 * entry. Take pity on the poor user and issue a helpful
429 * error message. NOTE: this is not a security breach,
430 * because all the info reported here is known at the frontend
431 * and must be assumed known to bad guys. We're merely helping
432 * out the less clueful good guys.
435 char hostinfo[NI_MAXHOST];
437 getnameinfo_all(&port->raddr.addr, port->raddr.salen,
438 hostinfo, sizeof(hostinfo),
444 (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
445 errmsg("no pg_hba.conf entry for host \"%s\", user \"%s\", database \"%s\", %s",
446 hostinfo, port->user_name, port->database_name,
447 port->ssl ? gettext("SSL on") : gettext("SSL off"))));
450 (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
451 errmsg("no pg_hba.conf entry for host \"%s\", user \"%s\", database \"%s\"",
452 hostinfo, port->user_name, port->database_name)));
458 /* Kerberos 4 only seems to work with AF_INET. */
459 if (port->raddr.addr.ss_family != AF_INET
460 || port->laddr.addr.ss_family != AF_INET)
462 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
463 errmsg("Kerberos 4 only supports IPv4 connections")));
464 sendAuthRequest(port, AUTH_REQ_KRB4);
465 status = pg_krb4_recvauth(port);
469 sendAuthRequest(port, AUTH_REQ_KRB5);
470 status = pg_krb5_recvauth(port);
475 * If we are doing ident on unix-domain sockets, use SCM_CREDS
476 * only if it is defined and SO_PEERCRED isn't.
478 #if !defined(HAVE_GETPEEREID) && !defined(SO_PEERCRED) && \
479 (defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || \
480 (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS)))
481 if (port->raddr.addr.ss_family == AF_UNIX)
483 #if defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
485 * Receive credentials on next message receipt, BSD/OS,
486 * NetBSD. We need to set this before the client sends the
491 if (setsockopt(port->sock, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
493 (errcode_for_socket_access(),
494 errmsg("could not enable credential reception: %m")));
497 sendAuthRequest(port, AUTH_REQ_SCM_CREDS);
500 status = authident(port);
504 sendAuthRequest(port, AUTH_REQ_MD5);
505 status = recv_and_check_password_packet(port);
509 sendAuthRequest(port, AUTH_REQ_CRYPT);
510 status = recv_and_check_password_packet(port);
514 sendAuthRequest(port, AUTH_REQ_PASSWORD);
515 status = recv_and_check_password_packet(port);
520 pam_port_cludge = port;
521 status = CheckPAMAuth(port, port->user_name, "");
530 if (status == STATUS_OK)
531 sendAuthRequest(port, AUTH_REQ_OK);
533 auth_failed(port, status);
538 * Send an authentication request packet to the frontend.
541 sendAuthRequest(Port *port, AuthRequest areq)
545 pq_beginmessage(&buf, 'R');
546 pq_sendint(&buf, (int32) areq, sizeof(int32));
548 /* Add the salt for encrypted passwords. */
549 if (areq == AUTH_REQ_MD5)
550 pq_sendbytes(&buf, port->md5Salt, 4);
551 else if (areq == AUTH_REQ_CRYPT)
552 pq_sendbytes(&buf, port->cryptSalt, 2);
557 * Flush message so client will see it, except for AUTH_REQ_OK, which
558 * need not be sent until we are ready for queries.
560 if (areq != AUTH_REQ_OK)
568 * PAM conversation function
572 pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg,
573 struct pam_response ** resp, void *appdata_ptr)
575 if (num_msg != 1 || msg[0]->msg_style != PAM_PROMPT_ECHO_OFF)
577 switch (msg[0]->msg_style)
581 (errmsg("error from underlying PAM layer: %s",
586 (errmsg("unsupported PAM conversation %d/%s",
587 msg[0]->msg_style, msg[0]->msg)));
595 * Workaround for Solaris 2.6 where the PAM library is broken and
596 * does not pass appdata_ptr to the conversation routine
598 appdata_ptr = pam_passwd;
602 * Password wasn't passed to PAM the first time around - let's go ask
603 * the client to send a password, which we then stuff into PAM.
605 if (strlen(appdata_ptr) == 0)
609 sendAuthRequest(pam_port_cludge, AUTH_REQ_PASSWORD);
610 passwd = recv_password_packet(pam_port_cludge);
613 return PAM_CONV_ERR; /* client didn't want to send password */
615 if (strlen(passwd) == 0)
618 (errmsg("empty password returned by client")));
621 appdata_ptr = passwd;
625 * Explicitly not using palloc here - PAM will free this memory in
628 *resp = calloc(num_msg, sizeof(struct pam_response));
632 (errcode(ERRCODE_OUT_OF_MEMORY),
633 errmsg("out of memory")));
637 (*resp)[0].resp = strdup((char *) appdata_ptr);
638 (*resp)[0].resp_retcode = 0;
640 return ((*resp)[0].resp ? PAM_SUCCESS : PAM_CONV_ERR);
645 * Check authentication against PAM.
648 CheckPAMAuth(Port *port, char *user, char *password)
651 pam_handle_t *pamh = NULL;
654 * Apparently, Solaris 2.6 is broken, and needs ugly static variable
657 pam_passwd = password;
660 * Set the application data portion of the conversation struct This is
661 * later used inside the PAM conversation to pass the password to the
662 * authentication module.
664 pam_passw_conv.appdata_ptr = (char *) password; /* from password above,
667 /* Optionally, one can set the service name in pg_hba.conf */
668 if (port->auth_arg && port->auth_arg[0] != '\0')
669 retval = pam_start(port->auth_arg, "pgsql@",
670 &pam_passw_conv, &pamh);
672 retval = pam_start(PGSQL_PAM_SERVICE, "pgsql@",
673 &pam_passw_conv, &pamh);
675 if (retval != PAM_SUCCESS)
678 (errmsg("could not create PAM authenticator: %s",
679 pam_strerror(pamh, retval))));
680 pam_passwd = NULL; /* Unset pam_passwd */
684 retval = pam_set_item(pamh, PAM_USER, user);
686 if (retval != PAM_SUCCESS)
689 (errmsg("pam_set_item(PAM_USER) failed: %s",
690 pam_strerror(pamh, retval))));
691 pam_passwd = NULL; /* Unset pam_passwd */
695 retval = pam_set_item(pamh, PAM_CONV, &pam_passw_conv);
697 if (retval != PAM_SUCCESS)
700 (errmsg("pam_set_item(PAM_CONV) failed: %s",
701 pam_strerror(pamh, retval))));
702 pam_passwd = NULL; /* Unset pam_passwd */
706 retval = pam_authenticate(pamh, 0);
708 if (retval != PAM_SUCCESS)
711 (errmsg("pam_authenticate failed: %s",
712 pam_strerror(pamh, retval))));
713 pam_passwd = NULL; /* Unset pam_passwd */
717 retval = pam_acct_mgmt(pamh, 0);
719 if (retval != PAM_SUCCESS)
722 (errmsg("pam_acct_mgmt failed: %s",
723 pam_strerror(pamh, retval))));
724 pam_passwd = NULL; /* Unset pam_passwd */
728 retval = pam_end(pamh, retval);
730 if (retval != PAM_SUCCESS)
733 (errmsg("could not release PAM authenticator: %s",
734 pam_strerror(pamh, retval))));
737 pam_passwd = NULL; /* Unset pam_passwd */
739 return (retval == PAM_SUCCESS ? STATUS_OK : STATUS_ERROR);
745 * Collect password response packet from frontend.
747 * Returns NULL if couldn't get password, else palloc'd string.
750 recv_password_packet(Port *port)
754 if (PG_PROTOCOL_MAJOR(port->proto) >= 3)
756 /* Expect 'p' message type */
759 mtype = pq_getbyte();
763 * If the client just disconnects without offering a password,
764 * don't make a log entry. This is legal per protocol spec
765 * and in fact commonly done by psql, so complaining just
770 (errcode(ERRCODE_PROTOCOL_VIOLATION),
771 errmsg("expected password response, got message type %d",
773 return NULL; /* EOF or bad message type */
778 /* For pre-3.0 clients, avoid log entry if they just disconnect */
779 if (pq_peekbyte() == EOF)
780 return NULL; /* EOF */
783 initStringInfo(&buf);
784 if (pq_getmessage(&buf, 1000)) /* receive password */
786 /* EOF - pq_getmessage already logged a suitable message */
792 * Apply sanity check: password packet length should agree with length
793 * of contained string. Note it is safe to use strlen here because
794 * StringInfo is guaranteed to have an appended '\0'.
796 if (strlen(buf.data) + 1 != buf.len)
798 (errcode(ERRCODE_PROTOCOL_VIOLATION),
799 errmsg("invalid password packet size")));
801 /* Do not echo password to logs, for security. */
803 (errmsg("received password packet")));
806 * Return the received string. Note we do not attempt to do any
807 * character-set conversion on it; since we don't yet know the
808 * client's encoding, there wouldn't be much point.
815 * Called when we have sent an authorization request for a password.
816 * Get the response and check it.
819 recv_and_check_password_packet(Port *port)
824 passwd = recv_password_packet(port);
827 return STATUS_EOF; /* client wouldn't send password */
829 result = md5_crypt_verify(port, port->user_name, passwd);