Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * fe-auth.c
4 : * The front-end (client) authorization routines
5 : *
6 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : * IDENTIFICATION
10 : * src/interfaces/libpq/fe-auth.c
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 :
15 : /*
16 : * INTERFACE ROUTINES
17 : * frontend (client) routines:
18 : * pg_fe_sendauth send authentication information
19 : * pg_fe_getauthname get user's name according to the client side
20 : * of the authentication system
21 : */
22 :
23 : #include "postgres_fe.h"
24 :
25 : #ifdef WIN32
26 : #include "win32.h"
27 : #else
28 : #include <unistd.h>
29 : #include <fcntl.h>
30 : #include <limits.h>
31 : #include <pwd.h>
32 : #include <sys/param.h> /* for MAXHOSTNAMELEN on most */
33 : #include <sys/socket.h>
34 : #ifdef HAVE_SYS_UCRED_H
35 : #include <sys/ucred.h>
36 : #endif
37 : #ifndef MAXHOSTNAMELEN
38 : #include <netdb.h> /* for MAXHOSTNAMELEN on some */
39 : #endif
40 : #endif
41 :
42 : #include "common/md5.h"
43 : #include "common/oauth-common.h"
44 : #include "common/scram-common.h"
45 : #include "fe-auth.h"
46 : #include "fe-auth-sasl.h"
47 : #include "fe-auth-oauth.h"
48 : #include "libpq-fe.h"
49 :
50 : #ifdef ENABLE_GSS
51 : /*
52 : * GSSAPI authentication system.
53 : */
54 :
55 : #include "fe-gssapi-common.h"
56 :
57 : /*
58 : * Continue GSS authentication with next token as needed.
59 : */
60 : static int
61 : pg_GSS_continue(PGconn *conn, int payloadlen)
62 : {
63 : OM_uint32 maj_stat,
64 : min_stat,
65 : lmin_s,
66 : gss_flags = GSS_C_MUTUAL_FLAG;
67 : gss_buffer_desc ginbuf;
68 : gss_buffer_desc goutbuf;
69 :
70 : /*
71 : * On first call, there's no input token. On subsequent calls, read the
72 : * input token into a GSS buffer.
73 : */
74 : if (conn->gctx != GSS_C_NO_CONTEXT)
75 : {
76 : ginbuf.length = payloadlen;
77 : ginbuf.value = malloc(payloadlen);
78 : if (!ginbuf.value)
79 : {
80 : libpq_append_conn_error(conn, "out of memory allocating GSSAPI buffer (%d)",
81 : payloadlen);
82 : return STATUS_ERROR;
83 : }
84 : if (pqGetnchar(ginbuf.value, payloadlen, conn))
85 : {
86 : /*
87 : * Shouldn't happen, because the caller should've ensured that the
88 : * whole message is already in the input buffer.
89 : */
90 : free(ginbuf.value);
91 : return STATUS_ERROR;
92 : }
93 : }
94 : else
95 : {
96 : ginbuf.length = 0;
97 : ginbuf.value = NULL;
98 : }
99 :
100 : /* finished parsing, trace server-to-client message */
101 : if (conn->Pfdebug)
102 : pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
103 :
104 : /* Only try to acquire credentials if GSS delegation isn't disabled. */
105 : if (!pg_GSS_have_cred_cache(&conn->gcred))
106 : conn->gcred = GSS_C_NO_CREDENTIAL;
107 :
108 : if (conn->gssdelegation && conn->gssdelegation[0] == '1')
109 : gss_flags |= GSS_C_DELEG_FLAG;
110 :
111 : maj_stat = gss_init_sec_context(&min_stat,
112 : conn->gcred,
113 : &conn->gctx,
114 : conn->gtarg_nam,
115 : GSS_C_NO_OID,
116 : gss_flags,
117 : 0,
118 : GSS_C_NO_CHANNEL_BINDINGS,
119 : (ginbuf.value == NULL) ? GSS_C_NO_BUFFER : &ginbuf,
120 : NULL,
121 : &goutbuf,
122 : NULL,
123 : NULL);
124 :
125 : free(ginbuf.value);
126 :
127 : if (goutbuf.length != 0)
128 : {
129 : /*
130 : * GSS generated data to send to the server. We don't care if it's the
131 : * first or subsequent packet, just send the same kind of password
132 : * packet.
133 : */
134 : conn->current_auth_response = AUTH_RESPONSE_GSS;
135 : if (pqPacketSend(conn, PqMsg_GSSResponse,
136 : goutbuf.value, goutbuf.length) != STATUS_OK)
137 : {
138 : gss_release_buffer(&lmin_s, &goutbuf);
139 : return STATUS_ERROR;
140 : }
141 : }
142 : gss_release_buffer(&lmin_s, &goutbuf);
143 :
144 : if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED)
145 : {
146 : pg_GSS_error(libpq_gettext("GSSAPI continuation error"),
147 : conn,
148 : maj_stat, min_stat);
149 : gss_release_name(&lmin_s, &conn->gtarg_nam);
150 : if (conn->gctx)
151 : gss_delete_sec_context(&lmin_s, &conn->gctx, GSS_C_NO_BUFFER);
152 : return STATUS_ERROR;
153 : }
154 :
155 : if (maj_stat == GSS_S_COMPLETE)
156 : {
157 : conn->client_finished_auth = true;
158 : gss_release_name(&lmin_s, &conn->gtarg_nam);
159 : conn->gssapi_used = true;
160 : }
161 :
162 : return STATUS_OK;
163 : }
164 :
165 : /*
166 : * Send initial GSS authentication token
167 : */
168 : static int
169 : pg_GSS_startup(PGconn *conn, int payloadlen)
170 : {
171 : int ret;
172 : char *host = conn->connhost[conn->whichhost].host;
173 :
174 : if (!(host && host[0] != '\0'))
175 : {
176 : libpq_append_conn_error(conn, "host name must be specified");
177 : return STATUS_ERROR;
178 : }
179 :
180 : if (conn->gctx)
181 : {
182 : libpq_append_conn_error(conn, "duplicate GSS authentication request");
183 : return STATUS_ERROR;
184 : }
185 :
186 : ret = pg_GSS_load_servicename(conn);
187 : if (ret != STATUS_OK)
188 : return ret;
189 :
190 : /*
191 : * Initial packet is the same as a continuation packet with no initial
192 : * context.
193 : */
194 : conn->gctx = GSS_C_NO_CONTEXT;
195 :
196 : return pg_GSS_continue(conn, payloadlen);
197 : }
198 : #endif /* ENABLE_GSS */
199 :
200 :
201 : #ifdef ENABLE_SSPI
202 : /*
203 : * SSPI authentication system (Windows only)
204 : */
205 :
206 : static void
207 : pg_SSPI_error(PGconn *conn, const char *mprefix, SECURITY_STATUS r)
208 : {
209 : char sysmsg[256];
210 :
211 : if (FormatMessage(FORMAT_MESSAGE_IGNORE_INSERTS |
212 : FORMAT_MESSAGE_FROM_SYSTEM,
213 : NULL, r, 0,
214 : sysmsg, sizeof(sysmsg), NULL) == 0)
215 : appendPQExpBuffer(&conn->errorMessage, "%s: SSPI error %x\n",
216 : mprefix, (unsigned int) r);
217 : else
218 : appendPQExpBuffer(&conn->errorMessage, "%s: %s (%x)\n",
219 : mprefix, sysmsg, (unsigned int) r);
220 : }
221 :
222 : /*
223 : * Continue SSPI authentication with next token as needed.
224 : */
225 : static int
226 : pg_SSPI_continue(PGconn *conn, int payloadlen)
227 : {
228 : SECURITY_STATUS r;
229 : CtxtHandle newContext;
230 : ULONG contextAttr;
231 : SecBufferDesc inbuf;
232 : SecBufferDesc outbuf;
233 : SecBuffer OutBuffers[1];
234 : SecBuffer InBuffers[1];
235 : char *inputbuf = NULL;
236 :
237 : if (conn->sspictx != NULL)
238 : {
239 : /*
240 : * On runs other than the first we have some data to send. Put this
241 : * data in a SecBuffer type structure.
242 : */
243 : inputbuf = malloc(payloadlen);
244 : if (!inputbuf)
245 : {
246 : libpq_append_conn_error(conn, "out of memory allocating SSPI buffer (%d)",
247 : payloadlen);
248 : return STATUS_ERROR;
249 : }
250 : if (pqGetnchar(inputbuf, payloadlen, conn))
251 : {
252 : /*
253 : * Shouldn't happen, because the caller should've ensured that the
254 : * whole message is already in the input buffer.
255 : */
256 : free(inputbuf);
257 : return STATUS_ERROR;
258 : }
259 :
260 : inbuf.ulVersion = SECBUFFER_VERSION;
261 : inbuf.cBuffers = 1;
262 : inbuf.pBuffers = InBuffers;
263 : InBuffers[0].pvBuffer = inputbuf;
264 : InBuffers[0].cbBuffer = payloadlen;
265 : InBuffers[0].BufferType = SECBUFFER_TOKEN;
266 : }
267 :
268 : /* finished parsing, trace server-to-client message */
269 : if (conn->Pfdebug)
270 : pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
271 :
272 : OutBuffers[0].pvBuffer = NULL;
273 : OutBuffers[0].BufferType = SECBUFFER_TOKEN;
274 : OutBuffers[0].cbBuffer = 0;
275 : outbuf.cBuffers = 1;
276 : outbuf.pBuffers = OutBuffers;
277 : outbuf.ulVersion = SECBUFFER_VERSION;
278 :
279 : r = InitializeSecurityContext(conn->sspicred,
280 : conn->sspictx,
281 : conn->sspitarget,
282 : ISC_REQ_ALLOCATE_MEMORY,
283 : 0,
284 : SECURITY_NETWORK_DREP,
285 : (conn->sspictx == NULL) ? NULL : &inbuf,
286 : 0,
287 : &newContext,
288 : &outbuf,
289 : &contextAttr,
290 : NULL);
291 :
292 : /* we don't need the input anymore */
293 : free(inputbuf);
294 :
295 : if (r != SEC_E_OK && r != SEC_I_CONTINUE_NEEDED)
296 : {
297 : pg_SSPI_error(conn, libpq_gettext("SSPI continuation error"), r);
298 :
299 : return STATUS_ERROR;
300 : }
301 :
302 : if (conn->sspictx == NULL)
303 : {
304 : /* On first run, transfer retrieved context handle */
305 : conn->sspictx = malloc(sizeof(CtxtHandle));
306 : if (conn->sspictx == NULL)
307 : {
308 : libpq_append_conn_error(conn, "out of memory");
309 : return STATUS_ERROR;
310 : }
311 : memcpy(conn->sspictx, &newContext, sizeof(CtxtHandle));
312 : }
313 :
314 : /*
315 : * If SSPI returned any data to be sent to the server (as it normally
316 : * would), send this data as a password packet.
317 : */
318 : if (outbuf.cBuffers > 0)
319 : {
320 : if (outbuf.cBuffers != 1)
321 : {
322 : /*
323 : * This should never happen, at least not for Kerberos
324 : * authentication. Keep check in case it shows up with other
325 : * authentication methods later.
326 : */
327 : appendPQExpBufferStr(&conn->errorMessage,
328 : "SSPI returned invalid number of output buffers\n");
329 : return STATUS_ERROR;
330 : }
331 :
332 : /*
333 : * If the negotiation is complete, there may be zero bytes to send.
334 : * The server is at this point not expecting any more data, so don't
335 : * send it.
336 : */
337 : if (outbuf.pBuffers[0].cbBuffer > 0)
338 : {
339 : conn->current_auth_response = AUTH_RESPONSE_GSS;
340 : if (pqPacketSend(conn, PqMsg_GSSResponse,
341 : outbuf.pBuffers[0].pvBuffer, outbuf.pBuffers[0].cbBuffer))
342 : {
343 : FreeContextBuffer(outbuf.pBuffers[0].pvBuffer);
344 : return STATUS_ERROR;
345 : }
346 : }
347 : FreeContextBuffer(outbuf.pBuffers[0].pvBuffer);
348 : }
349 :
350 : if (r == SEC_E_OK)
351 : conn->client_finished_auth = true;
352 :
353 : /* Cleanup is handled by the code in freePGconn() */
354 : return STATUS_OK;
355 : }
356 :
357 : /*
358 : * Send initial SSPI authentication token.
359 : * If use_negotiate is 0, use kerberos authentication package which is
360 : * compatible with Unix. If use_negotiate is 1, use the negotiate package
361 : * which supports both kerberos and NTLM, but is not compatible with Unix.
362 : */
363 : static int
364 : pg_SSPI_startup(PGconn *conn, int use_negotiate, int payloadlen)
365 : {
366 : SECURITY_STATUS r;
367 : TimeStamp expire;
368 : char *host = conn->connhost[conn->whichhost].host;
369 :
370 : if (conn->sspictx)
371 : {
372 : libpq_append_conn_error(conn, "duplicate SSPI authentication request");
373 : return STATUS_ERROR;
374 : }
375 :
376 : /*
377 : * Retrieve credentials handle
378 : */
379 : conn->sspicred = malloc(sizeof(CredHandle));
380 : if (conn->sspicred == NULL)
381 : {
382 : libpq_append_conn_error(conn, "out of memory");
383 : return STATUS_ERROR;
384 : }
385 :
386 : r = AcquireCredentialsHandle(NULL,
387 : use_negotiate ? "negotiate" : "kerberos",
388 : SECPKG_CRED_OUTBOUND,
389 : NULL,
390 : NULL,
391 : NULL,
392 : NULL,
393 : conn->sspicred,
394 : &expire);
395 : if (r != SEC_E_OK)
396 : {
397 : pg_SSPI_error(conn, libpq_gettext("could not acquire SSPI credentials"), r);
398 : free(conn->sspicred);
399 : conn->sspicred = NULL;
400 : return STATUS_ERROR;
401 : }
402 :
403 : /*
404 : * Compute target principal name. SSPI has a different format from GSSAPI,
405 : * but not more complex. We can skip the @REALM part, because Windows will
406 : * fill that in for us automatically.
407 : */
408 : if (!(host && host[0] != '\0'))
409 : {
410 : libpq_append_conn_error(conn, "host name must be specified");
411 : return STATUS_ERROR;
412 : }
413 : conn->sspitarget = malloc(strlen(conn->krbsrvname) + strlen(host) + 2);
414 : if (!conn->sspitarget)
415 : {
416 : libpq_append_conn_error(conn, "out of memory");
417 : return STATUS_ERROR;
418 : }
419 : sprintf(conn->sspitarget, "%s/%s", conn->krbsrvname, host);
420 :
421 : /*
422 : * Indicate that we're in SSPI authentication mode to make sure that
423 : * pg_SSPI_continue is called next time in the negotiation.
424 : */
425 : conn->usesspi = 1;
426 :
427 : return pg_SSPI_continue(conn, payloadlen);
428 : }
429 : #endif /* ENABLE_SSPI */
430 :
431 : /*
432 : * Initialize SASL authentication exchange.
433 : */
434 : static int
435 108 : pg_SASL_init(PGconn *conn, int payloadlen, bool *async)
436 : {
437 108 : char *initialresponse = NULL;
438 : int initialresponselen;
439 : const char *selected_mechanism;
440 : PQExpBufferData mechanism_buf;
441 108 : char *password = NULL;
442 : SASLStatus status;
443 :
444 108 : initPQExpBuffer(&mechanism_buf);
445 :
446 108 : if (conn->channel_binding[0] == 'r' && /* require */
447 8 : !conn->ssl_in_use)
448 : {
449 2 : libpq_append_conn_error(conn, "channel binding required, but SSL not in use");
450 2 : goto error;
451 : }
452 :
453 106 : if (conn->sasl_state && !conn->async_auth)
454 : {
455 0 : libpq_append_conn_error(conn, "duplicate SASL authentication request");
456 0 : goto error;
457 : }
458 :
459 : /*
460 : * Parse the list of SASL authentication mechanisms in the
461 : * AuthenticationSASL message, and select the best mechanism that we
462 : * support. Mechanisms are listed by order of decreasing importance.
463 : */
464 106 : selected_mechanism = NULL;
465 : for (;;)
466 : {
467 226 : if (pqGets(&mechanism_buf, conn))
468 : {
469 0 : appendPQExpBufferStr(&conn->errorMessage,
470 : "fe_sendauth: invalid authentication request from server: invalid list of authentication mechanisms\n");
471 0 : goto error;
472 : }
473 226 : if (PQExpBufferDataBroken(mechanism_buf))
474 0 : goto oom_error;
475 :
476 : /* An empty string indicates end of list */
477 226 : if (mechanism_buf.data[0] == '\0')
478 106 : break;
479 :
480 : /*
481 : * Select the mechanism to use. Pick SCRAM-SHA-256-PLUS over anything
482 : * else if a channel binding type is set and if the client supports it
483 : * (and did not set channel_binding=disable). Pick SCRAM-SHA-256 if
484 : * nothing else has already been picked. If we add more mechanisms, a
485 : * more refined priority mechanism might become necessary.
486 : */
487 120 : if (strcmp(mechanism_buf.data, SCRAM_SHA_256_PLUS_NAME) == 0)
488 : {
489 14 : if (conn->ssl_in_use)
490 : {
491 : /* The server has offered SCRAM-SHA-256-PLUS. */
492 :
493 : #ifdef USE_SSL
494 : /*
495 : * The client supports channel binding, which is chosen if
496 : * channel_binding is not disabled.
497 : */
498 14 : if (conn->channel_binding[0] != 'd') /* disable */
499 : {
500 10 : selected_mechanism = SCRAM_SHA_256_PLUS_NAME;
501 10 : conn->sasl = &pg_scram_mech;
502 10 : conn->password_needed = true;
503 : }
504 : #else
505 : /*
506 : * The client does not support channel binding. If it is
507 : * required, complain immediately instead of the error below
508 : * which would be confusing as the server is publishing
509 : * SCRAM-SHA-256-PLUS.
510 : */
511 : if (conn->channel_binding[0] == 'r') /* require */
512 : {
513 : libpq_append_conn_error(conn, "channel binding is required, but client does not support it");
514 : goto error;
515 : }
516 : #endif
517 : }
518 : else
519 : {
520 : /*
521 : * The server offered SCRAM-SHA-256-PLUS, but the connection
522 : * is not SSL-encrypted. That's not sane. Perhaps SSL was
523 : * stripped by a proxy? There's no point in continuing,
524 : * because the server will reject the connection anyway if we
525 : * try authenticate without channel binding even though both
526 : * the client and server supported it. The SCRAM exchange
527 : * checks for that, to prevent downgrade attacks.
528 : */
529 0 : libpq_append_conn_error(conn, "server offered SCRAM-SHA-256-PLUS authentication over a non-SSL connection");
530 0 : goto error;
531 : }
532 : }
533 106 : else if (strcmp(mechanism_buf.data, SCRAM_SHA_256_NAME) == 0 &&
534 : !selected_mechanism)
535 : {
536 96 : selected_mechanism = SCRAM_SHA_256_NAME;
537 96 : conn->sasl = &pg_scram_mech;
538 96 : conn->password_needed = true;
539 : }
540 10 : else if (strcmp(mechanism_buf.data, OAUTHBEARER_NAME) == 0 &&
541 : !selected_mechanism)
542 : {
543 0 : selected_mechanism = OAUTHBEARER_NAME;
544 0 : conn->sasl = &pg_oauth_mech;
545 0 : conn->password_needed = false;
546 : }
547 : }
548 :
549 106 : if (!selected_mechanism)
550 : {
551 0 : libpq_append_conn_error(conn, "none of the server's SASL authentication mechanisms are supported");
552 0 : goto error;
553 : }
554 :
555 : /* Make sure require_auth is satisfied. */
556 106 : if (conn->require_auth)
557 : {
558 24 : bool allowed = false;
559 :
560 40 : for (int i = 0; i < lengthof(conn->allowed_sasl_mechs); i++)
561 : {
562 32 : if (conn->sasl == conn->allowed_sasl_mechs[i])
563 : {
564 16 : allowed = true;
565 16 : break;
566 : }
567 : }
568 :
569 24 : if (!allowed)
570 : {
571 8 : libpq_append_conn_error(conn, "authentication method requirement \"%s\" failed: server requested %s authentication",
572 : conn->require_auth, selected_mechanism);
573 8 : goto error;
574 : }
575 : }
576 :
577 98 : if (conn->channel_binding[0] == 'r' && /* require */
578 6 : strcmp(selected_mechanism, SCRAM_SHA_256_PLUS_NAME) != 0)
579 : {
580 0 : libpq_append_conn_error(conn, "channel binding is required, but server did not offer an authentication method that supports channel binding");
581 0 : goto error;
582 : }
583 :
584 : /*
585 : * Now that the SASL mechanism has been chosen for the exchange,
586 : * initialize its state information.
587 : */
588 :
589 : /*
590 : * First, select the password to use for the exchange, complaining if
591 : * there isn't one and the selected SASL mechanism needs it.
592 : */
593 98 : if (conn->password_needed && !conn->scram_client_key_binary)
594 : {
595 90 : password = conn->connhost[conn->whichhost].password;
596 90 : if (password == NULL)
597 90 : password = conn->pgpass;
598 90 : if (password == NULL || password[0] == '\0')
599 : {
600 0 : appendPQExpBufferStr(&conn->errorMessage,
601 : PQnoPasswordSupplied);
602 0 : goto error;
603 : }
604 : }
605 :
606 : /* finished parsing, trace server-to-client message */
607 98 : if (conn->Pfdebug)
608 0 : pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
609 :
610 : Assert(conn->sasl);
611 :
612 98 : if (!conn->sasl_state)
613 : {
614 : /*
615 : * Initialize the SASL state information with all the information
616 : * gathered during the initial exchange.
617 : *
618 : * Note: Only tls-unique is supported for the moment.
619 : */
620 98 : conn->sasl_state = conn->sasl->init(conn,
621 : password,
622 : selected_mechanism);
623 98 : if (!conn->sasl_state)
624 0 : goto oom_error;
625 : }
626 : else
627 : {
628 : /*
629 : * This is only possible if we're returning from an async loop.
630 : * Disconnect it now.
631 : */
632 : Assert(conn->async_auth);
633 0 : conn->async_auth = NULL;
634 : }
635 :
636 : /* Get the mechanism-specific Initial Client Response, if any */
637 98 : status = conn->sasl->exchange(conn->sasl_state, false,
638 : NULL, -1,
639 : &initialresponse, &initialresponselen);
640 :
641 98 : if (status == SASL_FAILED)
642 0 : goto error;
643 :
644 98 : if (status == SASL_ASYNC)
645 : {
646 : /*
647 : * The mechanism should have set up the necessary callbacks; all we
648 : * need to do is signal the caller.
649 : *
650 : * In non-assertion builds, this postcondition is enforced at time of
651 : * use in PQconnectPoll().
652 : */
653 : Assert(conn->async_auth);
654 : Assert(conn->cleanup_async_auth);
655 :
656 0 : *async = true;
657 0 : return STATUS_OK;
658 : }
659 :
660 : /*
661 : * Build a SASLInitialResponse message, and send it.
662 : */
663 98 : if (pqPutMsgStart(PqMsg_SASLInitialResponse, conn))
664 0 : goto error;
665 98 : if (pqPuts(selected_mechanism, conn))
666 0 : goto error;
667 98 : if (initialresponse)
668 : {
669 98 : if (pqPutInt(initialresponselen, 4, conn))
670 0 : goto error;
671 98 : if (pqPutnchar(initialresponse, initialresponselen, conn))
672 0 : goto error;
673 : }
674 98 : conn->current_auth_response = AUTH_RESPONSE_SASL_INITIAL;
675 98 : if (pqPutMsgEnd(conn))
676 0 : goto error;
677 :
678 98 : if (pqFlush(conn))
679 0 : goto error;
680 :
681 98 : termPQExpBuffer(&mechanism_buf);
682 98 : free(initialresponse);
683 :
684 98 : return STATUS_OK;
685 :
686 10 : error:
687 10 : termPQExpBuffer(&mechanism_buf);
688 10 : free(initialresponse);
689 10 : return STATUS_ERROR;
690 :
691 0 : oom_error:
692 0 : termPQExpBuffer(&mechanism_buf);
693 0 : free(initialresponse);
694 0 : libpq_append_conn_error(conn, "out of memory");
695 0 : return STATUS_ERROR;
696 : }
697 :
698 : /*
699 : * Exchange a message for SASL communication protocol with the backend.
700 : * This should be used after calling pg_SASL_init to set up the status of
701 : * the protocol.
702 : */
703 : static int
704 184 : pg_SASL_continue(PGconn *conn, int payloadlen, bool final, bool *async)
705 : {
706 : char *output;
707 : int outputlen;
708 : int res;
709 : char *challenge;
710 : SASLStatus status;
711 :
712 : /* Read the SASL challenge from the AuthenticationSASLContinue message. */
713 184 : challenge = malloc(payloadlen + 1);
714 184 : if (!challenge)
715 : {
716 0 : libpq_append_conn_error(conn, "out of memory allocating SASL buffer (%d)",
717 : payloadlen);
718 0 : return STATUS_ERROR;
719 : }
720 :
721 184 : if (pqGetnchar(challenge, payloadlen, conn))
722 : {
723 0 : free(challenge);
724 0 : return STATUS_ERROR;
725 : }
726 :
727 : /* finished parsing, trace server-to-client message */
728 184 : if (conn->Pfdebug)
729 0 : pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
730 :
731 : /* For safety and convenience, ensure the buffer is NULL-terminated. */
732 184 : challenge[payloadlen] = '\0';
733 :
734 184 : status = conn->sasl->exchange(conn->sasl_state, final,
735 : challenge, payloadlen,
736 : &output, &outputlen);
737 184 : free(challenge); /* don't need the input anymore */
738 :
739 184 : if (status == SASL_ASYNC)
740 : {
741 : /*
742 : * The mechanism should have set up the necessary callbacks; all we
743 : * need to do is signal the caller.
744 : */
745 0 : *async = true;
746 :
747 : /*
748 : * The mechanism may optionally generate some output to send before
749 : * switching over to async auth, so continue onwards.
750 : */
751 : }
752 :
753 184 : if (final && status == SASL_CONTINUE)
754 : {
755 0 : if (outputlen != 0)
756 0 : free(output);
757 :
758 0 : libpq_append_conn_error(conn, "AuthenticationSASLFinal received from server, but SASL authentication was not completed");
759 0 : return STATUS_ERROR;
760 : }
761 :
762 : /*
763 : * If the exchange is not completed yet, we need to make sure that the
764 : * SASL mechanism has generated a message to send back.
765 : */
766 184 : if (output == NULL && status == SASL_CONTINUE)
767 : {
768 0 : libpq_append_conn_error(conn, "no client response found after SASL exchange success");
769 0 : return STATUS_ERROR;
770 : }
771 :
772 : /*
773 : * SASL allows zero-length responses, so this check uses "output" and not
774 : * "outputlen" to allow the case of an empty message.
775 : */
776 184 : if (output)
777 : {
778 : /*
779 : * Send the SASL response to the server.
780 : */
781 98 : conn->current_auth_response = AUTH_RESPONSE_SASL;
782 98 : res = pqPacketSend(conn, PqMsg_SASLResponse, output, outputlen);
783 98 : free(output);
784 :
785 98 : if (res != STATUS_OK)
786 0 : return STATUS_ERROR;
787 : }
788 :
789 184 : if (status == SASL_FAILED)
790 0 : return STATUS_ERROR;
791 :
792 184 : return STATUS_OK;
793 : }
794 :
795 : static int
796 84 : pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
797 : {
798 : int ret;
799 84 : char *crypt_pwd = NULL;
800 : const char *pwd_to_send;
801 : char md5Salt[4];
802 :
803 : /* Read the salt from the AuthenticationMD5Password message. */
804 84 : if (areq == AUTH_REQ_MD5)
805 : {
806 2 : if (pqGetnchar(md5Salt, 4, conn))
807 0 : return STATUS_ERROR; /* shouldn't happen */
808 : }
809 :
810 : /* finished parsing, trace server-to-client message */
811 84 : if (conn->Pfdebug)
812 0 : pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
813 :
814 : /* Encrypt the password if needed. */
815 :
816 84 : switch (areq)
817 : {
818 2 : case AUTH_REQ_MD5:
819 : {
820 : char *crypt_pwd2;
821 2 : const char *errstr = NULL;
822 :
823 : /* Allocate enough space for two MD5 hashes */
824 2 : crypt_pwd = malloc(2 * (MD5_PASSWD_LEN + 1));
825 2 : if (!crypt_pwd)
826 : {
827 0 : libpq_append_conn_error(conn, "out of memory");
828 0 : return STATUS_ERROR;
829 : }
830 :
831 2 : crypt_pwd2 = crypt_pwd + MD5_PASSWD_LEN + 1;
832 2 : if (!pg_md5_encrypt(password, conn->pguser,
833 2 : strlen(conn->pguser), crypt_pwd2,
834 : &errstr))
835 : {
836 0 : libpq_append_conn_error(conn, "could not encrypt password: %s", errstr);
837 0 : free(crypt_pwd);
838 0 : return STATUS_ERROR;
839 : }
840 2 : if (!pg_md5_encrypt(crypt_pwd2 + strlen("md5"), md5Salt,
841 : 4, crypt_pwd, &errstr))
842 : {
843 0 : libpq_append_conn_error(conn, "could not encrypt password: %s", errstr);
844 0 : free(crypt_pwd);
845 0 : return STATUS_ERROR;
846 : }
847 :
848 2 : pwd_to_send = crypt_pwd;
849 2 : break;
850 : }
851 82 : case AUTH_REQ_PASSWORD:
852 82 : pwd_to_send = password;
853 82 : break;
854 0 : default:
855 0 : return STATUS_ERROR;
856 : }
857 84 : conn->current_auth_response = AUTH_RESPONSE_PASSWORD;
858 84 : ret = pqPacketSend(conn, PqMsg_PasswordMessage,
859 84 : pwd_to_send, strlen(pwd_to_send) + 1);
860 84 : free(crypt_pwd);
861 84 : return ret;
862 : }
863 :
864 : /*
865 : * Translate a disallowed AuthRequest code into an error message.
866 : */
867 : static const char *
868 24 : auth_method_description(AuthRequest areq)
869 : {
870 24 : switch (areq)
871 : {
872 12 : case AUTH_REQ_PASSWORD:
873 12 : return libpq_gettext("server requested a cleartext password");
874 0 : case AUTH_REQ_MD5:
875 0 : return libpq_gettext("server requested a hashed password");
876 0 : case AUTH_REQ_GSS:
877 : case AUTH_REQ_GSS_CONT:
878 0 : return libpq_gettext("server requested GSSAPI authentication");
879 0 : case AUTH_REQ_SSPI:
880 0 : return libpq_gettext("server requested SSPI authentication");
881 12 : case AUTH_REQ_SASL:
882 : case AUTH_REQ_SASL_CONT:
883 : case AUTH_REQ_SASL_FIN:
884 12 : return libpq_gettext("server requested SASL authentication");
885 : }
886 :
887 0 : return libpq_gettext("server requested an unknown authentication type");
888 : }
889 :
890 : /*
891 : * Convenience macro for checking the allowed_auth_methods bitmask. Caller
892 : * must ensure that type is not greater than 31 (high bit of the bitmask).
893 : */
894 : #define auth_method_allowed(conn, type) \
895 : (((conn)->allowed_auth_methods & (1 << (type))) != 0)
896 :
897 : /*
898 : * Verify that the authentication request is expected, given the connection
899 : * parameters. This is especially important when the client wishes to
900 : * authenticate the server before any sensitive information is exchanged.
901 : */
902 : static bool
903 26962 : check_expected_areq(AuthRequest areq, PGconn *conn)
904 : {
905 26962 : bool result = true;
906 26962 : const char *reason = NULL;
907 :
908 : StaticAssertDecl((sizeof(conn->allowed_auth_methods) * CHAR_BIT) > AUTH_REQ_MAX,
909 : "AUTH_REQ_MAX overflows the allowed_auth_methods bitmask");
910 :
911 26962 : if (conn->sslcertmode[0] == 'r' /* require */
912 6 : && areq == AUTH_REQ_OK)
913 : {
914 : /*
915 : * Trade off a little bit of complexity to try to get these error
916 : * messages as precise as possible.
917 : */
918 6 : if (!conn->ssl_cert_requested)
919 : {
920 0 : libpq_append_conn_error(conn, "server did not request an SSL certificate");
921 0 : return false;
922 : }
923 6 : else if (!conn->ssl_cert_sent)
924 : {
925 2 : libpq_append_conn_error(conn, "server accepted connection without a valid SSL certificate");
926 2 : return false;
927 : }
928 : }
929 :
930 : /*
931 : * If the user required a specific auth method, or specified an allowed
932 : * set, then reject all others here, and make sure the server actually
933 : * completes an authentication exchange.
934 : */
935 26960 : if (conn->require_auth)
936 : {
937 144 : switch (areq)
938 : {
939 54 : case AUTH_REQ_OK:
940 :
941 : /*
942 : * Check to make sure we've actually finished our exchange (or
943 : * else that the user has allowed an authentication-less
944 : * connection).
945 : *
946 : * If the user has allowed both SCRAM and unauthenticated
947 : * (trust) connections, then this check will silently accept
948 : * partial SCRAM exchanges, where a misbehaving server does
949 : * not provide its verifier before sending an OK. This is
950 : * consistent with historical behavior, but it may be a point
951 : * to revisit in the future, since it could allow a server
952 : * that doesn't know the user's password to silently harvest
953 : * material for a brute force attack.
954 : */
955 54 : if (!conn->auth_required || conn->client_finished_auth)
956 : break;
957 :
958 : /*
959 : * No explicit authentication request was made by the server
960 : * -- or perhaps it was made and not completed, in the case of
961 : * SCRAM -- but there is one special case to check. If the
962 : * user allowed "gss", then a GSS-encrypted channel also
963 : * satisfies the check.
964 : */
965 : #ifdef ENABLE_GSS
966 : if (auth_method_allowed(conn, AUTH_REQ_GSS) && conn->gssenc)
967 : {
968 : /*
969 : * If implicit GSS auth has already been performed via GSS
970 : * encryption, we don't need to have performed an
971 : * AUTH_REQ_GSS exchange. This allows require_auth=gss to
972 : * be combined with gssencmode, since there won't be an
973 : * explicit authentication request in that case.
974 : */
975 : }
976 : else
977 : #endif
978 : {
979 14 : reason = libpq_gettext("server did not complete authentication");
980 14 : result = false;
981 : }
982 :
983 14 : break;
984 :
985 90 : case AUTH_REQ_PASSWORD:
986 : case AUTH_REQ_MD5:
987 : case AUTH_REQ_GSS:
988 : case AUTH_REQ_GSS_CONT:
989 : case AUTH_REQ_SSPI:
990 : case AUTH_REQ_SASL:
991 : case AUTH_REQ_SASL_CONT:
992 : case AUTH_REQ_SASL_FIN:
993 :
994 : /*
995 : * We don't handle these with the default case, to avoid
996 : * bit-shifting past the end of the allowed_auth_methods mask
997 : * if the server sends an unexpected AuthRequest.
998 : */
999 90 : result = auth_method_allowed(conn, areq);
1000 90 : break;
1001 :
1002 0 : default:
1003 0 : result = false;
1004 0 : break;
1005 : }
1006 26856 : }
1007 :
1008 26960 : if (!result)
1009 : {
1010 38 : if (!reason)
1011 24 : reason = auth_method_description(areq);
1012 :
1013 38 : libpq_append_conn_error(conn, "authentication method requirement \"%s\" failed: %s",
1014 : conn->require_auth, reason);
1015 38 : return result;
1016 : }
1017 :
1018 : /*
1019 : * When channel_binding=require, we must protect against two cases: (1) we
1020 : * must not respond to non-SASL authentication requests, which might leak
1021 : * information such as the client's password; and (2) even if we receive
1022 : * AUTH_REQ_OK, we still must ensure that channel binding has happened in
1023 : * order to authenticate the server.
1024 : */
1025 26922 : if (conn->channel_binding[0] == 'r' /* require */ )
1026 : {
1027 34 : switch (areq)
1028 : {
1029 20 : case AUTH_REQ_SASL:
1030 : case AUTH_REQ_SASL_CONT:
1031 : case AUTH_REQ_SASL_FIN:
1032 20 : break;
1033 8 : case AUTH_REQ_OK:
1034 8 : if (!conn->sasl || !conn->sasl->channel_bound(conn->sasl_state))
1035 : {
1036 2 : libpq_append_conn_error(conn, "channel binding required, but server authenticated client without channel binding");
1037 2 : result = false;
1038 : }
1039 8 : break;
1040 6 : default:
1041 6 : libpq_append_conn_error(conn, "channel binding required but not supported by server's authentication request");
1042 6 : result = false;
1043 6 : break;
1044 : }
1045 26888 : }
1046 :
1047 26922 : return result;
1048 : }
1049 :
1050 : /*
1051 : * pg_fe_sendauth
1052 : * client demux routine for processing an authentication request
1053 : *
1054 : * The server has sent us an authentication challenge (or OK). Send an
1055 : * appropriate response. The caller has ensured that the whole message is
1056 : * now in the input buffer, and has already read the type and length of
1057 : * it. We are responsible for reading any remaining extra data, specific
1058 : * to the authentication method. 'payloadlen' is the remaining length in
1059 : * the message.
1060 : *
1061 : * If *async is set to true on return, the client doesn't yet have enough
1062 : * information to respond, and the caller must temporarily switch to
1063 : * conn->async_auth() to continue driving the exchange.
1064 : */
1065 : int
1066 26962 : pg_fe_sendauth(AuthRequest areq, int payloadlen, PGconn *conn, bool *async)
1067 : {
1068 : int oldmsglen;
1069 :
1070 26962 : *async = false;
1071 :
1072 26962 : if (!check_expected_areq(areq, conn))
1073 48 : return STATUS_ERROR;
1074 :
1075 26914 : switch (areq)
1076 : {
1077 26536 : case AUTH_REQ_OK:
1078 26536 : break;
1079 :
1080 0 : case AUTH_REQ_KRB4:
1081 0 : libpq_append_conn_error(conn, "Kerberos 4 authentication not supported");
1082 0 : return STATUS_ERROR;
1083 :
1084 0 : case AUTH_REQ_KRB5:
1085 0 : libpq_append_conn_error(conn, "Kerberos 5 authentication not supported");
1086 0 : return STATUS_ERROR;
1087 :
1088 : #if defined(ENABLE_GSS) || defined(ENABLE_SSPI)
1089 : case AUTH_REQ_GSS:
1090 : #if !defined(ENABLE_SSPI)
1091 : /* no native SSPI, so use GSSAPI library for it */
1092 : case AUTH_REQ_SSPI:
1093 : #endif
1094 : {
1095 : int r;
1096 :
1097 : pglock_thread();
1098 :
1099 : /*
1100 : * If we have both GSS and SSPI support compiled in, use SSPI
1101 : * support by default. This is overridable by a connection
1102 : * string parameter. Note that when using SSPI we still leave
1103 : * the negotiate parameter off, since we want SSPI to use the
1104 : * GSSAPI kerberos protocol. For actual SSPI negotiate
1105 : * protocol, we use AUTH_REQ_SSPI.
1106 : */
1107 : #if defined(ENABLE_GSS) && defined(ENABLE_SSPI)
1108 : if (conn->gsslib && (pg_strcasecmp(conn->gsslib, "gssapi") == 0))
1109 : r = pg_GSS_startup(conn, payloadlen);
1110 : else
1111 : r = pg_SSPI_startup(conn, 0, payloadlen);
1112 : #elif defined(ENABLE_GSS) && !defined(ENABLE_SSPI)
1113 : r = pg_GSS_startup(conn, payloadlen);
1114 : #elif !defined(ENABLE_GSS) && defined(ENABLE_SSPI)
1115 : r = pg_SSPI_startup(conn, 0, payloadlen);
1116 : #endif
1117 : if (r != STATUS_OK)
1118 : {
1119 : /* Error message already filled in. */
1120 : pgunlock_thread();
1121 : return STATUS_ERROR;
1122 : }
1123 : pgunlock_thread();
1124 : }
1125 : break;
1126 :
1127 : case AUTH_REQ_GSS_CONT:
1128 : {
1129 : int r;
1130 :
1131 : pglock_thread();
1132 : #if defined(ENABLE_GSS) && defined(ENABLE_SSPI)
1133 : if (conn->usesspi)
1134 : r = pg_SSPI_continue(conn, payloadlen);
1135 : else
1136 : r = pg_GSS_continue(conn, payloadlen);
1137 : #elif defined(ENABLE_GSS) && !defined(ENABLE_SSPI)
1138 : r = pg_GSS_continue(conn, payloadlen);
1139 : #elif !defined(ENABLE_GSS) && defined(ENABLE_SSPI)
1140 : r = pg_SSPI_continue(conn, payloadlen);
1141 : #endif
1142 : if (r != STATUS_OK)
1143 : {
1144 : /* Error message already filled in. */
1145 : pgunlock_thread();
1146 : return STATUS_ERROR;
1147 : }
1148 : pgunlock_thread();
1149 : }
1150 : break;
1151 : #else /* defined(ENABLE_GSS) || defined(ENABLE_SSPI) */
1152 : /* No GSSAPI *or* SSPI support */
1153 0 : case AUTH_REQ_GSS:
1154 : case AUTH_REQ_GSS_CONT:
1155 0 : libpq_append_conn_error(conn, "GSSAPI authentication not supported");
1156 0 : return STATUS_ERROR;
1157 : #endif /* defined(ENABLE_GSS) || defined(ENABLE_SSPI) */
1158 :
1159 : #ifdef ENABLE_SSPI
1160 : case AUTH_REQ_SSPI:
1161 :
1162 : /*
1163 : * SSPI has its own startup message so libpq can decide which
1164 : * method to use. Indicate to pg_SSPI_startup that we want SSPI
1165 : * negotiation instead of Kerberos.
1166 : */
1167 : pglock_thread();
1168 : if (pg_SSPI_startup(conn, 1, payloadlen) != STATUS_OK)
1169 : {
1170 : /* Error message already filled in. */
1171 : pgunlock_thread();
1172 : return STATUS_ERROR;
1173 : }
1174 : pgunlock_thread();
1175 : break;
1176 : #else
1177 :
1178 : /*
1179 : * No SSPI support. However, if we have GSSAPI but not SSPI
1180 : * support, AUTH_REQ_SSPI will have been handled in the codepath
1181 : * for AUTH_REQ_GSS above, so don't duplicate the case label in
1182 : * that case.
1183 : */
1184 : #if !defined(ENABLE_GSS)
1185 0 : case AUTH_REQ_SSPI:
1186 0 : libpq_append_conn_error(conn, "SSPI authentication not supported");
1187 0 : return STATUS_ERROR;
1188 : #endif /* !define(ENABLE_GSS) */
1189 : #endif /* ENABLE_SSPI */
1190 :
1191 :
1192 0 : case AUTH_REQ_CRYPT:
1193 0 : libpq_append_conn_error(conn, "Crypt authentication not supported");
1194 0 : return STATUS_ERROR;
1195 :
1196 86 : case AUTH_REQ_MD5:
1197 : case AUTH_REQ_PASSWORD:
1198 : {
1199 : char *password;
1200 :
1201 86 : conn->password_needed = true;
1202 86 : password = conn->connhost[conn->whichhost].password;
1203 86 : if (password == NULL)
1204 76 : password = conn->pgpass;
1205 86 : if (password == NULL || password[0] == '\0')
1206 : {
1207 2 : appendPQExpBufferStr(&conn->errorMessage,
1208 : PQnoPasswordSupplied);
1209 2 : return STATUS_ERROR;
1210 : }
1211 84 : if (pg_password_sendauth(conn, password, areq) != STATUS_OK)
1212 : {
1213 0 : appendPQExpBufferStr(&conn->errorMessage,
1214 : "fe_sendauth: error sending password authentication\n");
1215 0 : return STATUS_ERROR;
1216 : }
1217 :
1218 : /* We expect no further authentication requests. */
1219 84 : conn->client_finished_auth = true;
1220 84 : break;
1221 : }
1222 :
1223 108 : case AUTH_REQ_SASL:
1224 :
1225 : /*
1226 : * The request contains the name (as assigned by IANA) of the
1227 : * authentication mechanism.
1228 : */
1229 108 : if (pg_SASL_init(conn, payloadlen, async) != STATUS_OK)
1230 : {
1231 : /* pg_SASL_init already set the error message */
1232 10 : return STATUS_ERROR;
1233 : }
1234 98 : break;
1235 :
1236 184 : case AUTH_REQ_SASL_CONT:
1237 : case AUTH_REQ_SASL_FIN:
1238 : {
1239 184 : bool final = false;
1240 :
1241 184 : if (conn->sasl_state == NULL)
1242 : {
1243 0 : appendPQExpBufferStr(&conn->errorMessage,
1244 : "fe_sendauth: invalid authentication request from server: AUTH_REQ_SASL_CONT without AUTH_REQ_SASL\n");
1245 0 : return STATUS_ERROR;
1246 : }
1247 184 : oldmsglen = conn->errorMessage.len;
1248 :
1249 184 : if (areq == AUTH_REQ_SASL_FIN)
1250 86 : final = true;
1251 :
1252 184 : if (pg_SASL_continue(conn, payloadlen, final, async) != STATUS_OK)
1253 : {
1254 : /*
1255 : * Append a generic error message unless pg_SASL_continue
1256 : * did set a more specific one already.
1257 : */
1258 0 : if (conn->errorMessage.len == oldmsglen)
1259 0 : appendPQExpBufferStr(&conn->errorMessage,
1260 : "fe_sendauth: error in SASL authentication\n");
1261 0 : return STATUS_ERROR;
1262 : }
1263 184 : break;
1264 : }
1265 :
1266 0 : default:
1267 0 : libpq_append_conn_error(conn, "authentication method %u not supported", areq);
1268 0 : return STATUS_ERROR;
1269 : }
1270 :
1271 26902 : return STATUS_OK;
1272 : }
1273 :
1274 :
1275 : /*
1276 : * pg_fe_getusername
1277 : *
1278 : * Returns a pointer to malloc'd space containing the name of the
1279 : * specified user_id. If there is an error, return NULL, and append
1280 : * a suitable error message to *errorMessage if that's not NULL.
1281 : *
1282 : * Caution: on Windows, the user_id argument is ignored, and we always
1283 : * fetch the current user's name.
1284 : */
1285 : char *
1286 25630 : pg_fe_getusername(uid_t user_id, PQExpBuffer errorMessage)
1287 : {
1288 25630 : char *result = NULL;
1289 25630 : const char *name = NULL;
1290 :
1291 : #ifdef WIN32
1292 : /* Microsoft recommends buffer size of UNLEN+1, where UNLEN = 256 */
1293 : char username[256 + 1];
1294 : DWORD namesize = sizeof(username);
1295 : #else
1296 : struct passwd pwbuf;
1297 25630 : struct passwd *pw = NULL;
1298 : char buf[1024];
1299 : int rc;
1300 : #endif
1301 :
1302 : #ifdef WIN32
1303 : if (GetUserName(username, &namesize))
1304 : name = username;
1305 : else if (errorMessage)
1306 : libpq_append_error(errorMessage,
1307 : "user name lookup failure: error code %lu",
1308 : GetLastError());
1309 : #else
1310 25630 : rc = getpwuid_r(user_id, &pwbuf, buf, sizeof buf, &pw);
1311 25630 : if (rc != 0)
1312 : {
1313 0 : errno = rc;
1314 0 : if (errorMessage)
1315 0 : libpq_append_error(errorMessage, "could not look up local user ID %ld: %m", (long) user_id);
1316 : }
1317 25630 : else if (!pw)
1318 : {
1319 0 : if (errorMessage)
1320 0 : libpq_append_error(errorMessage, "local user with ID %ld does not exist", (long) user_id);
1321 : }
1322 : else
1323 25630 : name = pw->pw_name;
1324 : #endif
1325 :
1326 25630 : if (name)
1327 : {
1328 25630 : result = strdup(name);
1329 25630 : if (result == NULL && errorMessage)
1330 0 : libpq_append_error(errorMessage, "out of memory");
1331 : }
1332 :
1333 25630 : return result;
1334 : }
1335 :
1336 : /*
1337 : * pg_fe_getauthname
1338 : *
1339 : * Returns a pointer to malloc'd space containing whatever name the user
1340 : * has authenticated to the system. If there is an error, return NULL,
1341 : * and append a suitable error message to *errorMessage if that's not NULL.
1342 : */
1343 : char *
1344 25630 : pg_fe_getauthname(PQExpBuffer errorMessage)
1345 : {
1346 : #ifdef WIN32
1347 : return pg_fe_getusername(0, errorMessage);
1348 : #else
1349 25630 : return pg_fe_getusername(geteuid(), errorMessage);
1350 : #endif
1351 : }
1352 :
1353 :
1354 : /*
1355 : * PQencryptPassword -- exported routine to encrypt a password with MD5
1356 : *
1357 : * This function is equivalent to calling PQencryptPasswordConn with
1358 : * "md5" as the encryption method, except that this doesn't require
1359 : * a connection object. This function is deprecated, use
1360 : * PQencryptPasswordConn instead.
1361 : */
1362 : char *
1363 0 : PQencryptPassword(const char *passwd, const char *user)
1364 : {
1365 : char *crypt_pwd;
1366 0 : const char *errstr = NULL;
1367 :
1368 0 : crypt_pwd = malloc(MD5_PASSWD_LEN + 1);
1369 0 : if (!crypt_pwd)
1370 0 : return NULL;
1371 :
1372 0 : if (!pg_md5_encrypt(passwd, user, strlen(user), crypt_pwd, &errstr))
1373 : {
1374 0 : free(crypt_pwd);
1375 0 : return NULL;
1376 : }
1377 :
1378 0 : return crypt_pwd;
1379 : }
1380 :
1381 : /*
1382 : * PQencryptPasswordConn -- exported routine to encrypt a password
1383 : *
1384 : * This is intended to be used by client applications that wish to send
1385 : * commands like ALTER USER joe PASSWORD 'pwd'. The password need not
1386 : * be sent in cleartext if it is encrypted on the client side. This is
1387 : * good because it ensures the cleartext password won't end up in logs,
1388 : * pg_stat displays, etc. We export the function so that clients won't
1389 : * be dependent on low-level details like whether the encryption is MD5
1390 : * or something else.
1391 : *
1392 : * Arguments are a connection object, the cleartext password, the SQL
1393 : * name of the user it is for, and a string indicating the algorithm to
1394 : * use for encrypting the password. If algorithm is NULL, this queries
1395 : * the server for the current 'password_encryption' value. If you wish
1396 : * to avoid that, e.g. to avoid blocking, you can execute
1397 : * 'show password_encryption' yourself before calling this function, and
1398 : * pass it as the algorithm.
1399 : *
1400 : * Return value is a malloc'd string. The client may assume the string
1401 : * doesn't contain any special characters that would require escaping.
1402 : * On error, an error message is stored in the connection object, and
1403 : * returns NULL.
1404 : */
1405 : char *
1406 2 : PQencryptPasswordConn(PGconn *conn, const char *passwd, const char *user,
1407 : const char *algorithm)
1408 : {
1409 : #define MAX_ALGORITHM_NAME_LEN 50
1410 : char algobuf[MAX_ALGORITHM_NAME_LEN + 1];
1411 2 : char *crypt_pwd = NULL;
1412 :
1413 2 : if (!conn)
1414 0 : return NULL;
1415 :
1416 2 : pqClearConnErrorState(conn);
1417 :
1418 : /* If no algorithm was given, ask the server. */
1419 2 : if (algorithm == NULL)
1420 : {
1421 : PGresult *res;
1422 : char *val;
1423 :
1424 2 : res = PQexec(conn, "show password_encryption");
1425 2 : if (res == NULL)
1426 : {
1427 : /* PQexec() should've set conn->errorMessage already */
1428 0 : return NULL;
1429 : }
1430 2 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
1431 : {
1432 : /* PQexec() should've set conn->errorMessage already */
1433 0 : PQclear(res);
1434 0 : return NULL;
1435 : }
1436 2 : if (PQntuples(res) != 1 || PQnfields(res) != 1)
1437 : {
1438 0 : PQclear(res);
1439 0 : libpq_append_conn_error(conn, "unexpected shape of result set returned for SHOW");
1440 0 : return NULL;
1441 : }
1442 2 : val = PQgetvalue(res, 0, 0);
1443 :
1444 2 : if (strlen(val) > MAX_ALGORITHM_NAME_LEN)
1445 : {
1446 0 : PQclear(res);
1447 0 : libpq_append_conn_error(conn, "\"password_encryption\" value too long");
1448 0 : return NULL;
1449 : }
1450 2 : strcpy(algobuf, val);
1451 2 : PQclear(res);
1452 :
1453 2 : algorithm = algobuf;
1454 : }
1455 :
1456 : /*
1457 : * Also accept "on" and "off" as aliases for "md5", because
1458 : * password_encryption was a boolean before PostgreSQL 10. We refuse to
1459 : * send the password in plaintext even if it was "off".
1460 : */
1461 2 : if (strcmp(algorithm, "on") == 0 ||
1462 2 : strcmp(algorithm, "off") == 0)
1463 0 : algorithm = "md5";
1464 :
1465 : /*
1466 : * Ok, now we know what algorithm to use
1467 : */
1468 2 : if (strcmp(algorithm, "scram-sha-256") == 0)
1469 : {
1470 2 : const char *errstr = NULL;
1471 :
1472 2 : crypt_pwd = pg_fe_scram_build_secret(passwd,
1473 : conn->scram_sha_256_iterations,
1474 : &errstr);
1475 2 : if (!crypt_pwd)
1476 0 : libpq_append_conn_error(conn, "could not encrypt password: %s", errstr);
1477 : }
1478 0 : else if (strcmp(algorithm, "md5") == 0)
1479 : {
1480 0 : crypt_pwd = malloc(MD5_PASSWD_LEN + 1);
1481 0 : if (crypt_pwd)
1482 : {
1483 0 : const char *errstr = NULL;
1484 :
1485 0 : if (!pg_md5_encrypt(passwd, user, strlen(user), crypt_pwd, &errstr))
1486 : {
1487 0 : libpq_append_conn_error(conn, "could not encrypt password: %s", errstr);
1488 0 : free(crypt_pwd);
1489 0 : crypt_pwd = NULL;
1490 : }
1491 : }
1492 : else
1493 0 : libpq_append_conn_error(conn, "out of memory");
1494 : }
1495 : else
1496 : {
1497 0 : libpq_append_conn_error(conn, "unrecognized password encryption algorithm \"%s\"",
1498 : algorithm);
1499 0 : return NULL;
1500 : }
1501 :
1502 2 : return crypt_pwd;
1503 : }
1504 :
1505 : /*
1506 : * PQchangePassword -- exported routine to change a password
1507 : *
1508 : * This is intended to be used by client applications that wish to
1509 : * change the password for a user. The password is not sent in
1510 : * cleartext because it is encrypted on the client side. This is
1511 : * good because it ensures the cleartext password is never known by
1512 : * the server, and therefore won't end up in logs, pg_stat displays,
1513 : * etc. The password encryption is performed by PQencryptPasswordConn(),
1514 : * which is passed a NULL for the algorithm argument. Hence encryption
1515 : * is done according to the server's password_encryption
1516 : * setting. We export the function so that clients won't be dependent
1517 : * on the implementation specific details with respect to how the
1518 : * server changes passwords.
1519 : *
1520 : * Arguments are a connection object, the SQL name of the target user,
1521 : * and the cleartext password.
1522 : *
1523 : * Return value is the PGresult of the executed ALTER USER statement
1524 : * or NULL if we never get there. The caller is responsible to PQclear()
1525 : * the returned PGresult.
1526 : *
1527 : * PQresultStatus() should be called to check the return value for errors,
1528 : * and PQerrorMessage() used to get more information about such errors.
1529 : */
1530 : PGresult *
1531 2 : PQchangePassword(PGconn *conn, const char *user, const char *passwd)
1532 : {
1533 2 : char *encrypted_password = PQencryptPasswordConn(conn, passwd,
1534 : user, NULL);
1535 :
1536 2 : if (!encrypted_password)
1537 : {
1538 : /* PQencryptPasswordConn() already registered the error */
1539 0 : return NULL;
1540 : }
1541 : else
1542 : {
1543 2 : char *fmtpw = PQescapeLiteral(conn, encrypted_password,
1544 : strlen(encrypted_password));
1545 :
1546 : /* no longer needed, so clean up now */
1547 2 : PQfreemem(encrypted_password);
1548 :
1549 2 : if (!fmtpw)
1550 : {
1551 : /* PQescapeLiteral() already registered the error */
1552 0 : return NULL;
1553 : }
1554 : else
1555 : {
1556 2 : char *fmtuser = PQescapeIdentifier(conn, user, strlen(user));
1557 :
1558 2 : if (!fmtuser)
1559 : {
1560 : /* PQescapeIdentifier() already registered the error */
1561 0 : PQfreemem(fmtpw);
1562 0 : return NULL;
1563 : }
1564 : else
1565 : {
1566 : PQExpBufferData buf;
1567 : PGresult *res;
1568 :
1569 2 : initPQExpBuffer(&buf);
1570 2 : printfPQExpBuffer(&buf, "ALTER USER %s PASSWORD %s",
1571 : fmtuser, fmtpw);
1572 :
1573 2 : res = PQexec(conn, buf.data);
1574 :
1575 : /* clean up */
1576 2 : termPQExpBuffer(&buf);
1577 2 : PQfreemem(fmtuser);
1578 2 : PQfreemem(fmtpw);
1579 :
1580 2 : return res;
1581 : }
1582 : }
1583 : }
1584 : }
1585 :
1586 : PQauthDataHook_type PQauthDataHook = PQdefaultAuthDataHook;
1587 :
1588 : PQauthDataHook_type
1589 0 : PQgetAuthDataHook(void)
1590 : {
1591 0 : return PQauthDataHook;
1592 : }
1593 :
1594 : void
1595 0 : PQsetAuthDataHook(PQauthDataHook_type hook)
1596 : {
1597 0 : PQauthDataHook = hook ? hook : PQdefaultAuthDataHook;
1598 0 : }
1599 :
1600 : int
1601 0 : PQdefaultAuthDataHook(PGauthData type, PGconn *conn, void *data)
1602 : {
1603 0 : return 0; /* handle nothing */
1604 : }
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