1 /*-------------------------------------------------------------------------
4 * Routines to handle network authentication
6 * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
11 * $Header: /cvsroot/pgsql/src/backend/libpq/auth.c,v 1.98 2003/04/17 22:26:01 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 int recv_and_check_password_packet(Port *port);
42 char *pg_krb_server_keyfile;
45 #ifdef HAVE_PAM_PAM_APPL_H
46 #include <pam/pam_appl.h>
48 #ifdef HAVE_SECURITY_PAM_APPL_H
49 #include <security/pam_appl.h>
52 #define PGSQL_PAM_SERVICE "postgresql" /* Service name passed to PAM */
54 static int CheckPAMAuth(Port *port, char *user, char *password);
55 static int pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg,
56 struct pam_response ** resp, void *appdata_ptr);
58 static struct pam_conv pam_passw_conv = {
59 &pam_passwd_conv_proc,
63 static char *pam_passwd = NULL; /* Workaround for Solaris 2.6 brokenness */
64 static Port *pam_port_cludge; /* Workaround for passing "Port *port"
65 * into pam_passwd_conv_proc */
69 /*----------------------------------------------------------------
70 * MIT Kerberos authentication system - protocol version 4
71 *----------------------------------------------------------------
77 * pg_krb4_recvauth -- server routine to receive authentication information
80 * Nothing unusual here, except that we compare the username obtained from
81 * the client's setup packet to the authenticated name. (We have to retain
82 * the name in the setup packet since we have to retain the ability to handle
83 * unauthenticated connections.)
86 pg_krb4_recvauth(Port *port)
88 long krbopts = 0; /* one-way authentication */
90 char instance[INST_SZ + 1],
91 version[KRB_SENDAUTH_VLEN + 1];
93 Key_schedule key_sched;
96 strcpy(instance, "*"); /* don't care, but arg gets expanded
98 status = krb_recvauth(krbopts,
106 pg_krb_server_keyfile,
109 if (status != KSUCCESS)
111 elog(LOG, "pg_krb4_recvauth: kerberos error: %s",
112 krb_err_txt[status]);
115 if (strncmp(version, PG_KRB4_VERSION, KRB_SENDAUTH_VLEN) != 0)
117 elog(LOG, "pg_krb4_recvauth: protocol version \"%s\" != \"%s\"",
118 version, PG_KRB4_VERSION);
121 if (strncmp(port->user, auth_data.pname, SM_DATABASE_USER) != 0)
123 elog(LOG, "pg_krb4_recvauth: name \"%s\" != \"%s\"",
124 port->user, auth_data.pname);
133 pg_krb4_recvauth(Port *port)
135 elog(LOG, "pg_krb4_recvauth: Kerberos not implemented on this server");
142 /*----------------------------------------------------------------
143 * MIT Kerberos authentication system - protocol version 5
144 *----------------------------------------------------------------
151 * pg_an_to_ln -- return the local name corresponding to an authentication
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.
164 pg_an_to_ln(char *aname)
168 if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
175 * Various krb5 state which is not connection specfic, and a flag to
176 * indicate whether we have initialised it yet.
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;
187 krb5_error_code retval;
189 if (pg_krb5_initialised)
192 retval = krb5_init_context(&pg_krb5_context);
195 elog(LOG, "pg_krb5_init: krb5_init_context returned Kerberos error %d",
197 com_err("postgres", retval, "while initializing krb5");
201 retval = krb5_kt_resolve(pg_krb5_context, pg_krb_server_keyfile, &pg_krb5_keytab);
204 elog(LOG, "pg_krb5_init: krb5_kt_resolve returned Kerberos error %d",
206 com_err("postgres", retval, "while resolving keytab file %s",
207 pg_krb_server_keyfile);
208 krb5_free_context(pg_krb5_context);
212 retval = krb5_sname_to_principal(pg_krb5_context, NULL, PG_KRB_SRVNAM,
213 KRB5_NT_SRV_HST, &pg_krb5_server);
216 elog(LOG, "pg_krb5_init: krb5_sname_to_principal returned Kerberos error %d",
218 com_err("postgres", retval,
219 "while getting server principal for service %s",
221 krb5_kt_close(pg_krb5_context, pg_krb5_keytab);
222 krb5_free_context(pg_krb5_context);
226 pg_krb5_initialised = 1;
232 * pg_krb5_recvauth -- server routine to receive authentication information
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.
239 * We have our own keytab file because postgres is unlikely to run as root,
240 * and so cannot read the default keytab.
243 pg_krb5_recvauth(Port *port)
245 krb5_error_code retval;
247 krb5_auth_context auth_context = NULL;
251 ret = pg_krb5_init();
252 if (ret != STATUS_OK)
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);
260 elog(LOG, "pg_krb5_recvauth: krb5_recvauth returned Kerberos error %d",
262 com_err("postgres", retval, "from krb5_recvauth");
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.
271 * I have no idea why this is considered necessary.
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);
280 #error "bogus configuration"
284 elog(LOG, "pg_krb5_recvauth: krb5_unparse_name returned Kerberos error %d",
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);
292 kusername = pg_an_to_ln(kusername);
293 if (strncmp(port->user, kusername, SM_DATABASE_USER))
295 elog(LOG, "pg_krb5_recvauth: user name \"%s\" != krb5 name \"%s\"",
296 port->user, kusername);
302 krb5_free_ticket(pg_krb5_context, ticket);
303 krb5_auth_con_free(pg_krb5_context, auth_context);
312 pg_krb5_recvauth(Port *port)
314 elog(LOG, "pg_krb5_recvauth: Kerberos not implemented on this server");
321 * Tell the user the authentication failed, but not (much about) why.
323 * There is a tradeoff here between security concerns and making life
324 * unnecessarily difficult for legitimate users. We would not, for example,
325 * want to report the password we were expecting to receive...
326 * But it seems useful to report the username and authorization method
327 * in use, and these are items that must be presumed known to an attacker
329 * Note that many sorts of failure report additional information in the
330 * postmaster log, which we hope is only readable by good guys.
333 auth_failed(Port *port, int status)
335 const char *authmethod = "Unknown auth method:";
338 * If we failed due to EOF from client, just quit; there's no point in
339 * trying to send a message to the client, and not much point in
340 * logging the failure in the postmaster log. (Logging the failure
341 * might be desirable, were it not for the fact that libpq closes the
342 * connection unceremoniously if challenged for a password when it
343 * hasn't got one to send. We'll get a useless log entry for every
344 * psql connection under password auth, even if it's perfectly
345 * successful, if we log STATUS_EOF events.)
347 if (status == STATUS_EOF)
350 switch (port->auth_method)
353 authmethod = "Rejected host:";
356 authmethod = "Kerberos4";
359 authmethod = "Kerberos5";
362 authmethod = "Trusted";
365 authmethod = "IDENT";
370 authmethod = "Password";
379 elog(FATAL, "%s authentication failed for user \"%s\"",
380 authmethod, port->user_name);
386 * Client authentication starts here. If there is an error, this
387 * function does not return and the backend process is terminated.
390 ClientAuthentication(Port *port)
392 int status = STATUS_ERROR;
395 * Get the authentication method to use for this frontend/database
396 * combination. Note: a failure return indicates a problem with the
397 * hba config file, not with the request. hba.c should have dropped
398 * an error message into the postmaster logfile if it failed.
400 if (hba_getauthmethod(port) != STATUS_OK)
401 elog(FATAL, "Missing or erroneous pg_hba.conf file, see postmaster log for details");
403 switch (port->auth_method)
408 * This could have come from an explicit "reject" entry in
409 * pg_hba.conf, but more likely it means there was no matching
410 * entry. Take pity on the poor user and issue a helpful
411 * error message. NOTE: this is not a security breach,
412 * because all the info reported here is known at the frontend
413 * and must be assumed known to bad guys. We're merely helping
414 * out the less clueful good guys.
417 const char *hostinfo = "localhost";
419 char ip_hostinfo[INET6_ADDRSTRLEN];
421 char ip_hostinfo[INET_ADDRSTRLEN];
423 if (isAF_INETx(port->raddr.sa.sa_family) )
424 hostinfo = SockAddr_ntop(&port->raddr, ip_hostinfo,
425 sizeof(ip_hostinfo), 1);
428 "No pg_hba.conf entry for host %s, user %s, database %s",
429 hostinfo, port->user_name, port->database_name);
434 sendAuthRequest(port, AUTH_REQ_KRB4);
435 status = pg_krb4_recvauth(port);
439 sendAuthRequest(port, AUTH_REQ_KRB5);
440 status = pg_krb5_recvauth(port);
444 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || \
445 (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS)) && \
446 !defined(HAVE_GETPEEREID) && !defined(SO_PEERCRED)
449 * If we are doing ident on unix-domain sockets, use SCM_CREDS
450 * only if it is defined and SO_PEERCRED isn't.
452 #if defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
455 * Receive credentials on next message receipt, BSD/OS,
456 * NetBSD. We need to set this before the client sends the
462 if (setsockopt(port->sock, 0, LOCAL_CREDS, &on, sizeof(on)) < 0)
463 elog(FATAL, "pg_local_sendauth: can't do setsockopt: %m");
466 if (port->raddr.sa.sa_family == AF_UNIX)
467 sendAuthRequest(port, AUTH_REQ_SCM_CREDS);
469 status = authident(port);
473 sendAuthRequest(port, AUTH_REQ_MD5);
474 status = recv_and_check_password_packet(port);
478 sendAuthRequest(port, AUTH_REQ_CRYPT);
479 status = recv_and_check_password_packet(port);
483 sendAuthRequest(port, AUTH_REQ_PASSWORD);
484 status = recv_and_check_password_packet(port);
489 pam_port_cludge = port;
490 status = CheckPAMAuth(port, port->user, "");
499 if (status == STATUS_OK)
500 sendAuthRequest(port, AUTH_REQ_OK);
502 auth_failed(port, status);
507 * Send an authentication request packet to the frontend.
510 sendAuthRequest(Port *port, AuthRequest areq)
514 pq_beginmessage(&buf);
515 pq_sendbyte(&buf, 'R');
516 pq_sendint(&buf, (int32) areq, sizeof(int32));
518 /* Add the salt for encrypted passwords. */
519 if (areq == AUTH_REQ_MD5)
520 pq_sendbytes(&buf, port->md5Salt, 4);
521 else if (areq == AUTH_REQ_CRYPT)
522 pq_sendbytes(&buf, port->cryptSalt, 2);
527 * Flush message so client will see it, except for AUTH_REQ_OK, which
528 * need not be sent until we are ready for queries.
530 if (areq != AUTH_REQ_OK)
538 * PAM conversation function
542 pam_passwd_conv_proc(int num_msg, const struct pam_message ** msg, struct pam_response ** resp, void *appdata_ptr)
547 if (num_msg != 1 || msg[0]->msg_style != PAM_PROMPT_ECHO_OFF)
549 switch (msg[0]->msg_style)
552 elog(LOG, "pam_passwd_conv_proc: Error from underlying PAM layer: '%s'",
556 elog(LOG, "pam_passwd_conv_proc: Unexpected PAM conversation %d/'%s'",
557 msg[0]->msg_style, msg[0]->msg);
565 * Workaround for Solaris 2.6 where the PAM library is broken and
566 * does not pass appdata_ptr to the conversation routine
568 appdata_ptr = pam_passwd;
572 * Password wasn't passed to PAM the first time around - let's go ask
573 * the client to send a password, which we then stuff into PAM.
575 if (strlen(appdata_ptr) == 0)
577 sendAuthRequest(pam_port_cludge, AUTH_REQ_PASSWORD);
578 if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
579 return PAM_CONV_ERR; /* client didn't want to send password */
581 initStringInfo(&buf);
582 if (pq_getstr_bounded(&buf, 1000) == EOF)
583 return PAM_CONV_ERR; /* EOF while reading password */
585 /* Do not echo failed password to logs, for security. */
586 elog(DEBUG5, "received PAM packet");
588 if (strlen(buf.data) == 0)
590 elog(LOG, "pam_passwd_conv_proc: no password");
593 appdata_ptr = buf.data;
597 * Explicitly not using palloc here - PAM will free this memory in
600 *resp = calloc(num_msg, sizeof(struct pam_response));
603 elog(LOG, "pam_passwd_conv_proc: Out of memory!");
609 (*resp)[0].resp = strdup((char *) appdata_ptr);
610 (*resp)[0].resp_retcode = 0;
612 return ((*resp)[0].resp ? PAM_SUCCESS : PAM_CONV_ERR);
617 * Check authentication against PAM.
620 CheckPAMAuth(Port *port, char *user, char *password)
623 pam_handle_t *pamh = NULL;
626 * Apparently, Solaris 2.6 is broken, and needs ugly static variable
629 pam_passwd = password;
632 * Set the application data portion of the conversation struct This is
633 * later used inside the PAM conversation to pass the password to the
634 * authentication module.
636 pam_passw_conv.appdata_ptr = (char *) password; /* from password above,
639 /* Optionally, one can set the service name in pg_hba.conf */
640 if (port->auth_arg && port->auth_arg[0] != '\0')
641 retval = pam_start(port->auth_arg, "pgsql@",
642 &pam_passw_conv, &pamh);
644 retval = pam_start(PGSQL_PAM_SERVICE, "pgsql@",
645 &pam_passw_conv, &pamh);
647 if (retval != PAM_SUCCESS)
649 elog(LOG, "CheckPAMAuth: Failed to create PAM authenticator: '%s'",
650 pam_strerror(pamh, retval));
651 pam_passwd = NULL; /* Unset pam_passwd */
655 retval = pam_set_item(pamh, PAM_USER, user);
657 if (retval != PAM_SUCCESS)
659 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_USER) failed: '%s'",
660 pam_strerror(pamh, retval));
661 pam_passwd = NULL; /* Unset pam_passwd */
665 retval = pam_set_item(pamh, PAM_CONV, &pam_passw_conv);
667 if (retval != PAM_SUCCESS)
669 elog(LOG, "CheckPAMAuth: pam_set_item(PAM_CONV) failed: '%s'",
670 pam_strerror(pamh, retval));
671 pam_passwd = NULL; /* Unset pam_passwd */
675 retval = pam_authenticate(pamh, 0);
677 if (retval != PAM_SUCCESS)
679 elog(LOG, "CheckPAMAuth: pam_authenticate failed: '%s'",
680 pam_strerror(pamh, retval));
681 pam_passwd = NULL; /* Unset pam_passwd */
685 retval = pam_acct_mgmt(pamh, 0);
687 if (retval != PAM_SUCCESS)
689 elog(LOG, "CheckPAMAuth: pam_acct_mgmt failed: '%s'",
690 pam_strerror(pamh, retval));
691 pam_passwd = NULL; /* Unset pam_passwd */
695 retval = pam_end(pamh, retval);
697 if (retval != PAM_SUCCESS)
699 elog(LOG, "CheckPAMAuth: Failed to release PAM authenticator: '%s'",
700 pam_strerror(pamh, retval));
703 pam_passwd = NULL; /* Unset pam_passwd */
705 return (retval == PAM_SUCCESS ? STATUS_OK : STATUS_ERROR);
711 * Called when we have received the password packet.
714 recv_and_check_password_packet(Port *port)
720 if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
721 return STATUS_EOF; /* client didn't want to send password */
723 initStringInfo(&buf);
724 if (pq_getstr_bounded(&buf, 1000) == EOF) /* receive password */
731 * We don't actually use the password packet length the frontend sent
732 * us; however, it's a reasonable sanity check to ensure that we
733 * actually read as much data as we expected to.
735 * The password packet size is the length of the buffer, plus the size
736 * field itself (4 bytes), plus a 1-byte terminator.
738 if (len != (buf.len + 4 + 1))
739 elog(LOG, "unexpected password packet size: read %d, expected %d",
740 buf.len + 4 + 1, len);
742 /* Do not echo password to logs, for security. */
743 elog(DEBUG5, "received password packet");
745 result = md5_crypt_verify(port, port->user_name, buf.data);