1 /*-------------------------------------------------------------------------
4 * The front-end (client) authorization routines
6 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
9 * NOTE: the error message strings returned by this module must not
10 * exceed INITIAL_EXPBUFFER_SIZE (currently 256 bytes).
13 * $PostgreSQL: pgsql/src/interfaces/libpq/fe-auth.c,v 1.97 2004/12/31 22:03:50 pgsql Exp $
15 *-------------------------------------------------------------------------
20 * frontend (client) routines:
21 * fe_sendauth send authentication information
22 * fe_getauthname get user's name according to the client side
23 * of the authentication system
24 * fe_setauthsvc set frontend authentication service
25 * fe_getauthsvc get current frontend authentication service
31 #include "postgres_fe.h"
39 #include <sys/types.h>
40 #include <sys/param.h> /* for MAXHOSTNAMELEN on most */
41 #include <sys/socket.h>
42 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || defined(HAVE_STRUCT_SOCKCRED)
44 #include <sys/ucred.h>
46 #ifndef MAXHOSTNAMELEN
47 #include <netdb.h> /* for MAXHOSTNAMELEN on some */
57 #include "libpq-int.h"
59 #include "libpq/crypt.h"
63 * common definitions for generic fe/be routines
66 #define STARTUP_MSG 7 /* Initialise a connection */
67 #define STARTUP_KRB4_MSG 10 /* krb4 session follows */
68 #define STARTUP_KRB5_MSG 11 /* krb5 session follows */
69 #define STARTUP_PASSWORD_MSG 14 /* Password follows */
73 const char *name; /* service nickname (for command line) */
74 MsgType msgtype; /* startup packet header type */
75 int allowed; /* initially allowed (before command line
80 * Command-line parsing routines use this structure to map nicknames
81 * onto service types (and the startup packets to use with them).
83 * Programs receiving an authentication request use this structure to
84 * decide which authentication service types are currently permitted.
85 * By default, all authentication systems compiled into the system are
86 * allowed. Unauthenticated connections are disallowed unless there
87 * isn't any authentication system.
89 static const struct authsvc authsvcs[] = {
91 {"krb4", STARTUP_KRB4_MSG, 1},
92 {"kerberos", STARTUP_KRB4_MSG, 1},
95 {"krb5", STARTUP_KRB5_MSG, 1},
96 {"kerberos", STARTUP_KRB5_MSG, 1},
98 {UNAUTHNAME, STARTUP_MSG,
99 #if defined(KRB4) || defined(KRB5)
101 #else /* !(KRB4 || KRB5) */
103 #endif /* !(KRB4 || KRB5) */
105 {"password", STARTUP_PASSWORD_MSG, 0}
108 static const int n_authsvcs = sizeof(authsvcs) / sizeof(struct authsvc);
112 * MIT Kerberos authentication system - protocol version 4
117 /* for some reason, this is not defined in krb.h ... */
118 extern char *tkt_string(void);
121 * pg_krb4_init -- initialization performed before any Kerberos calls are made
123 * For v4, all we need to do is make sure the library routines get the right
124 * ticket file if we want them to see a special one. (They will open the file
131 static int init_done = 0;
138 * If the user set PGREALM, then we use a ticket file with a special
139 * name: <usual-ticket-file-name>@<PGREALM-value>
141 if ((realm = getenv("PGREALM")))
143 char tktbuf[MAXPGPATH];
145 (void) snprintf(tktbuf, sizeof(tktbuf), "%s@%s", tkt_string(), realm);
146 krb_set_tkt_string(tktbuf);
151 * pg_krb4_authname -- returns a pointer to static space containing whatever
152 * name the user has authenticated to the system
154 * We obtain this information by digging around in the ticket file.
157 pg_krb4_authname(char *PQerrormsg)
159 char instance[INST_SZ + 1];
160 char realm[REALM_SZ + 1];
162 static char name[SNAME_SZ + 1] = "";
169 name[SNAME_SZ] = '\0';
170 status = krb_get_tf_fullname(tkt_string(), name, instance, realm);
171 if (status != KSUCCESS)
173 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
174 "pg_krb4_authname: krb_get_tf_fullname: %s\n",
175 krb_err_txt[status]);
182 * pg_krb4_sendauth -- client routine to send authentication information to
185 * This routine does not do mutual authentication, nor does it return enough
186 * information to do encrypted connections. But then, if we want to do
187 * encrypted connections, we'll have to redesign the whole RPC mechanism
190 * If the user is too lazy to feed us a hostname, we try to come up with
191 * something other than "localhost" since the hostname is used as an
192 * instance and instance names in v4 databases are usually actual hostnames
193 * (canonicalized to omit all domain suffixes).
196 pg_krb4_sendauth(char *PQerrormsg, int sock,
197 struct sockaddr_in * laddr,
198 struct sockaddr_in * raddr,
199 const char *hostname)
201 long krbopts = 0; /* one-way authentication */
204 char hostbuf[MAXHOSTNAMELEN];
205 const char *realm = getenv("PGREALM"); /* NULL == current realm */
207 if (!hostname || !(*hostname))
209 if (gethostname(hostbuf, MAXHOSTNAMELEN) < 0)
210 strcpy(hostbuf, "localhost");
216 status = krb_sendauth(krbopts,
229 if (status != KSUCCESS)
231 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
232 libpq_gettext("Kerberos 4 error: %s\n"),
233 krb_err_txt[status]);
242 * MIT Kerberos authentication system - protocol version 5
248 * pg_an_to_ln -- return the local name corresponding to an authentication
251 * XXX Assumes that the first aname component is the user name. This is NOT
252 * necessarily so, since an aname can actually be something out of your
253 * worst X.400 nightmare, like
254 * ORGANIZATION=U. C. Berkeley/NAME=Paul M. Aoki@CS.BERKELEY.EDU
255 * Note that the MIT an_to_ln code does the same thing if you don't
256 * provide an aname mapping database...it may be a better idea to use
257 * krb5_an_to_ln, except that it punts if multiple components are found,
258 * and we can't afford to punt.
261 pg_an_to_ln(char *aname)
265 if ((p = strchr(aname, '/')) || (p = strchr(aname, '@')))
272 * Various krb5 state which is not connection specific, and a flag to
273 * indicate whether we have initialised it yet.
275 static int pg_krb5_initialised;
276 static krb5_context pg_krb5_context;
277 static krb5_ccache pg_krb5_ccache;
278 static krb5_principal pg_krb5_client;
279 static char *pg_krb5_name;
283 pg_krb5_init(char *PQerrormsg)
285 krb5_error_code retval;
287 if (pg_krb5_initialised)
290 retval = krb5_init_context(&pg_krb5_context);
293 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
294 "pg_krb5_init: krb5_init_context: %s\n",
295 error_message(retval));
299 retval = krb5_cc_default(pg_krb5_context, &pg_krb5_ccache);
302 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
303 "pg_krb5_init: krb5_cc_default: %s\n",
304 error_message(retval));
305 krb5_free_context(pg_krb5_context);
309 retval = krb5_cc_get_principal(pg_krb5_context, pg_krb5_ccache,
313 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
314 "pg_krb5_init: krb5_cc_get_principal: %s\n",
315 error_message(retval));
316 krb5_cc_close(pg_krb5_context, pg_krb5_ccache);
317 krb5_free_context(pg_krb5_context);
321 retval = krb5_unparse_name(pg_krb5_context, pg_krb5_client, &pg_krb5_name);
324 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
325 "pg_krb5_init: krb5_unparse_name: %s\n",
326 error_message(retval));
327 krb5_free_principal(pg_krb5_context, pg_krb5_client);
328 krb5_cc_close(pg_krb5_context, pg_krb5_ccache);
329 krb5_free_context(pg_krb5_context);
333 pg_krb5_name = pg_an_to_ln(pg_krb5_name);
335 pg_krb5_initialised = 1;
341 * pg_krb5_authname -- returns a pointer to static space containing whatever
342 * name the user has authenticated to the system
345 pg_krb5_authname(char *PQerrormsg)
347 if (pg_krb5_init(PQerrormsg) != STATUS_OK)
355 * pg_krb5_sendauth -- client routine to send authentication information to
359 pg_krb5_sendauth(char *PQerrormsg, int sock, const char *hostname)
361 krb5_error_code retval;
363 krb5_principal server;
364 krb5_auth_context auth_context = NULL;
365 krb5_error *err_ret = NULL;
368 ret = pg_krb5_init(PQerrormsg);
369 if (ret != STATUS_OK)
372 retval = krb5_sname_to_principal(pg_krb5_context, hostname, PG_KRB_SRVNAM,
373 KRB5_NT_SRV_HST, &server);
376 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
377 "pg_krb5_sendauth: krb5_sname_to_principal: %s\n",
378 error_message(retval));
383 * libpq uses a non-blocking socket. But kerberos needs a blocking
384 * socket, and we have to block somehow to do mutual authentication
385 * anyway. So we temporarily make it blocking.
387 flags = fcntl(sock, F_GETFL);
388 if (flags < 0 || fcntl(sock, F_SETFL, (long) (flags & ~O_NONBLOCK)))
392 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
393 libpq_gettext("could not set socket to blocking mode: %s\n"), pqStrerror(errno, sebuf, sizeof(sebuf)));
394 krb5_free_principal(pg_krb5_context, server);
398 retval = krb5_sendauth(pg_krb5_context, &auth_context,
399 (krb5_pointer) & sock, PG_KRB_SRVNAM,
400 pg_krb5_client, server,
401 AP_OPTS_MUTUAL_REQUIRED,
402 NULL, 0, /* no creds, use ccache instead */
403 pg_krb5_ccache, &err_ret, NULL, NULL);
406 if (retval == KRB5_SENDAUTH_REJECTED && err_ret)
408 #if defined(HAVE_KRB5_ERROR_TEXT_DATA)
409 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
410 libpq_gettext("Kerberos 5 authentication rejected: %*s\n"),
411 (int) err_ret->text.length, err_ret->text.data);
412 #elif defined(HAVE_KRB5_ERROR_E_DATA)
413 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
414 libpq_gettext("Kerberos 5 authentication rejected: %*s\n"),
415 (int) err_ret->e_data->length,
416 (const char *) err_ret->e_data->data);
418 #error "bogus configuration"
423 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
424 "krb5_sendauth: %s\n", error_message(retval));
428 krb5_free_error(pg_krb5_context, err_ret);
433 krb5_free_principal(pg_krb5_context, server);
435 if (fcntl(sock, F_SETFL, (long) flags))
439 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
440 libpq_gettext("could not restore non-blocking mode on socket: %s\n"),
441 pqStrerror(errno, sebuf, sizeof(sebuf)));
450 * Respond to AUTH_REQ_SCM_CREDS challenge.
452 * Note: current backends will not use this challenge if HAVE_GETPEEREID
453 * or SO_PEERCRED is defined, but pre-7.4 backends might, so compile the
457 pg_local_sendauth(char *PQerrormsg, PGconn *conn)
459 #if defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || \
460 (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS))
465 #ifdef HAVE_STRUCT_CMSGCRED
466 /* Prevent padding */
467 char cmsgmem[sizeof(struct cmsghdr) + sizeof(struct cmsgcred)];
469 /* Point to start of first structure */
470 struct cmsghdr *cmsg = (struct cmsghdr *) cmsgmem;
474 * The backend doesn't care what we send here, but it wants exactly
475 * one character to force recvmsg() to block and wait for us.
481 memset(&msg, 0, sizeof(msg));
485 #ifdef HAVE_STRUCT_CMSGCRED
486 /* Create control header, FreeBSD */
487 msg.msg_control = cmsg;
488 msg.msg_controllen = sizeof(cmsgmem);
489 memset(cmsg, 0, sizeof(cmsgmem));
490 cmsg->cmsg_len = sizeof(cmsgmem);
491 cmsg->cmsg_level = SOL_SOCKET;
492 cmsg->cmsg_type = SCM_CREDS;
495 if (sendmsg(conn->sock, &msg, 0) == -1)
499 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
500 "pg_local_sendauth: sendmsg: %s\n",
501 pqStrerror(errno, sebuf, sizeof(sebuf)));
506 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
507 libpq_gettext("SCM_CRED authentication method not supported\n"));
513 pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
518 /* Encrypt the password if needed. */
526 if (!(crypt_pwd = malloc(MD5_PASSWD_LEN + 1)) ||
527 !(crypt_pwd2 = malloc(MD5_PASSWD_LEN + 1)))
529 fprintf(stderr, libpq_gettext("out of memory\n"));
532 if (!EncryptMD5(password, conn->pguser,
533 strlen(conn->pguser), crypt_pwd2))
539 if (!EncryptMD5(crypt_pwd2 + strlen("md5"), conn->md5Salt,
540 sizeof(conn->md5Salt), crypt_pwd))
553 StrNCpy(salt, conn->cryptSalt, 3);
554 crypt_pwd = crypt(password, salt);
557 case AUTH_REQ_PASSWORD:
558 /* discard const so we can assign it */
559 crypt_pwd = (char *) password;
564 /* Packet has a message type as of protocol 3.0 */
565 if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3)
566 ret = pqPacketSend(conn, 'p', crypt_pwd, strlen(crypt_pwd) + 1);
568 ret = pqPacketSend(conn, 0, crypt_pwd, strlen(crypt_pwd) + 1);
569 if (areq == AUTH_REQ_MD5)
575 * fe_sendauth -- client demux routine for outgoing authentication information
578 fe_sendauth(AuthRequest areq, PGconn *conn, const char *hostname,
579 const char *password, char *PQerrormsg)
581 #if !defined(KRB4) && !defined(KRB5)
582 (void) hostname; /* not used */
593 if (pg_krb4_sendauth(PQerrormsg, conn->sock,
594 (struct sockaddr_in *) & conn->laddr.addr,
595 (struct sockaddr_in *) & conn->raddr.addr,
596 hostname) != STATUS_OK)
598 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
599 libpq_gettext("Kerberos 4 authentication failed\n"));
606 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
607 libpq_gettext("Kerberos 4 authentication not supported\n"));
614 if (pg_krb5_sendauth(PQerrormsg, conn->sock,
615 hostname) != STATUS_OK)
617 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
618 libpq_gettext("Kerberos 5 authentication failed\n"));
625 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
626 libpq_gettext("Kerberos 5 authentication not supported\n"));
632 case AUTH_REQ_PASSWORD:
633 if (password == NULL || *password == '\0')
635 (void) snprintf(PQerrormsg, PQERRORMSG_LENGTH,
636 PQnoPasswordSupplied);
639 if (pg_password_sendauth(conn, password, areq) != STATUS_OK)
641 (void) snprintf(PQerrormsg, PQERRORMSG_LENGTH,
642 "fe_sendauth: error sending password authentication\n");
647 case AUTH_REQ_SCM_CREDS:
648 if (pg_local_sendauth(PQerrormsg, conn) != STATUS_OK)
653 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
654 libpq_gettext("authentication method %u not supported\n"), areq);
665 * Set/return the authentication service currently selected for use by the
666 * frontend. (You can only use one in the frontend, obviously.)
668 * NB: This is not thread-safe if different threads try to select different
669 * authentication services! It's OK for fe_getauthsvc to select the default,
670 * since that will be the same for all threads, but direct application use
671 * of fe_setauthsvc is not thread-safe. However, use of fe_setauthsvc is
672 * deprecated anyway...
675 static int pg_authsvc = -1;
678 fe_setauthsvc(const char *name, char *PQerrormsg)
682 for (i = 0; i < n_authsvcs; ++i)
683 if (strcmp(name, authsvcs[i].name) == 0)
690 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
691 libpq_gettext("invalid authentication service name \"%s\", ignored\n"),
698 fe_getauthsvc(char *PQerrormsg)
700 if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
702 fe_setauthsvc(DEFAULT_CLIENT_AUTHSVC, PQerrormsg);
703 if (pg_authsvc < 0 || pg_authsvc >= n_authsvcs)
705 /* Can only get here if DEFAULT_CLIENT_AUTHSVC is misdefined */
709 return authsvcs[pg_authsvc].msgtype;
713 * fe_getauthname -- returns a pointer to dynamic space containing whatever
714 * name the user has authenticated to the system
715 * if there is an error, return the error message in PQerrormsg
718 fe_getauthname(char *PQerrormsg)
720 const char *name = NULL;
724 authsvc = fe_getauthsvc(PQerrormsg);
726 /* this just guards against broken DEFAULT_CLIENT_AUTHSVC, see above */
728 return NULL; /* leave original error message in place */
732 if (authsvc == STARTUP_KRB4_MSG)
733 name = pg_krb4_authname(PQerrormsg);
736 if (authsvc == STARTUP_KRB5_MSG)
737 name = pg_krb5_authname(PQerrormsg);
740 if (authsvc == STARTUP_MSG
741 || (authsvc == STARTUP_KRB4_MSG && !name)
742 || (authsvc == STARTUP_KRB5_MSG && !name))
746 DWORD namesize = sizeof(username) - 1;
748 if (GetUserName(username, &namesize))
752 struct passwd pwdstr;
753 struct passwd *pw = NULL;
755 if (pqGetpwuid(geteuid(), &pwdstr,
756 pwdbuf, sizeof(pwdbuf), &pw) == 0)
761 if (authsvc != STARTUP_MSG && authsvc != STARTUP_KRB4_MSG && authsvc != STARTUP_KRB5_MSG)
762 snprintf(PQerrormsg, PQERRORMSG_LENGTH,
763 libpq_gettext("fe_getauthname: invalid authentication system: %d\n"),
766 if (name && (authn = (char *) malloc(strlen(name) + 1)))