TLA Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * fe-auth.c
4 : * The front-end (client) authorization routines
5 : *
6 : * Portions Copyright (c) 1996-2023, 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 <sys/param.h> /* for MAXHOSTNAMELEN on most */
31 : #include <sys/socket.h>
32 : #ifdef HAVE_SYS_UCRED_H
33 : #include <sys/ucred.h>
34 : #endif
35 : #ifndef MAXHOSTNAMELEN
36 : #include <netdb.h> /* for MAXHOSTNAMELEN on some */
37 : #endif
38 : #endif
39 :
40 : #include "common/md5.h"
41 : #include "common/scram-common.h"
42 : #include "fe-auth.h"
43 : #include "fe-auth-sasl.h"
44 : #include "libpq-fe.h"
45 :
46 : #ifdef ENABLE_GSS
47 : /*
48 : * GSSAPI authentication system.
49 : */
50 :
51 : #include "fe-gssapi-common.h"
52 :
53 : /*
54 : * Continue GSS authentication with next token as needed.
55 : */
56 : static int
57 CBC 11 : pg_GSS_continue(PGconn *conn, int payloadlen)
58 : {
59 : OM_uint32 maj_stat,
60 : min_stat,
61 : lmin_s;
62 : gss_buffer_desc ginbuf;
63 : gss_buffer_desc goutbuf;
64 :
65 : /*
66 : * On first call, there's no input token. On subsequent calls, read the
67 : * input token into a GSS buffer.
68 : */
69 11 : if (conn->gctx != GSS_C_NO_CONTEXT)
70 : {
71 5 : ginbuf.length = payloadlen;
72 5 : ginbuf.value = malloc(payloadlen);
73 5 : if (!ginbuf.value)
74 : {
75 UNC 0 : libpq_append_conn_error(conn, "out of memory allocating GSSAPI buffer (%d)",
76 : payloadlen);
77 UIC 0 : return STATUS_ERROR;
78 ECB : }
79 GIC 5 : if (pqGetnchar(ginbuf.value, payloadlen, conn))
80 : {
81 : /*
82 : * Shouldn't happen, because the caller should've ensured that the
83 : * whole message is already in the input buffer.
84 EUB : */
85 UBC 0 : free(ginbuf.value);
86 UIC 0 : return STATUS_ERROR;
87 : }
88 : }
89 : else
90 ECB : {
91 CBC 6 : ginbuf.length = 0;
92 GIC 6 : ginbuf.value = NULL;
93 : }
94 ECB :
95 GIC 11 : maj_stat = gss_init_sec_context(&min_stat,
96 : GSS_C_NO_CREDENTIAL,
97 : &conn->gctx,
98 : conn->gtarg_nam,
99 : GSS_C_NO_OID,
100 : GSS_C_MUTUAL_FLAG,
101 : 0,
102 ECB : GSS_C_NO_CHANNEL_BINDINGS,
103 GIC 11 : (ginbuf.value == NULL) ? GSS_C_NO_BUFFER : &ginbuf,
104 : NULL,
105 : &goutbuf,
106 : NULL,
107 : NULL);
108 ECB :
109 GNC 11 : free(ginbuf.value);
110 :
111 GIC 11 : if (goutbuf.length != 0)
112 : {
113 : /*
114 : * GSS generated data to send to the server. We don't care if it's the
115 : * first or subsequent packet, just send the same kind of password
116 ECB : * packet.
117 : */
118 GIC 5 : if (pqPacketSend(conn, 'p',
119 GBC 5 : goutbuf.value, goutbuf.length) != STATUS_OK)
120 EUB : {
121 UIC 0 : gss_release_buffer(&lmin_s, &goutbuf);
122 0 : return STATUS_ERROR;
123 ECB : }
124 : }
125 CBC 11 : gss_release_buffer(&lmin_s, &goutbuf);
126 :
127 11 : if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED)
128 : {
129 GIC 1 : pg_GSS_error(libpq_gettext("GSSAPI continuation error"),
130 ECB : conn,
131 : maj_stat, min_stat);
132 GBC 1 : gss_release_name(&lmin_s, &conn->gtarg_nam);
133 CBC 1 : if (conn->gctx)
134 UIC 0 : gss_delete_sec_context(&lmin_s, &conn->gctx, GSS_C_NO_BUFFER);
135 GIC 1 : return STATUS_ERROR;
136 ECB : }
137 :
138 CBC 10 : if (maj_stat == GSS_S_COMPLETE)
139 : {
140 GNC 5 : conn->client_finished_auth = true;
141 CBC 5 : gss_release_name(&lmin_s, &conn->gtarg_nam);
142 : }
143 :
144 GIC 10 : return STATUS_OK;
145 ECB : }
146 :
147 : /*
148 : * Send initial GSS authentication token
149 : */
150 : static int
151 GIC 6 : pg_GSS_startup(PGconn *conn, int payloadlen)
152 ECB : {
153 : int ret;
154 GIC 6 : char *host = conn->connhost[conn->whichhost].host;
155 ECB :
156 GIC 6 : if (!(host && host[0] != '\0'))
157 ECB : {
158 UNC 0 : libpq_append_conn_error(conn, "host name must be specified");
159 UBC 0 : return STATUS_ERROR;
160 : }
161 :
162 CBC 6 : if (conn->gctx)
163 : {
164 UNC 0 : libpq_append_conn_error(conn, "duplicate GSS authentication request");
165 UIC 0 : return STATUS_ERROR;
166 : }
167 ECB :
168 CBC 6 : ret = pg_GSS_load_servicename(conn);
169 GBC 6 : if (ret != STATUS_OK)
170 UIC 0 : return ret;
171 :
172 : /*
173 : * Initial packet is the same as a continuation packet with no initial
174 : * context.
175 ECB : */
176 GIC 6 : conn->gctx = GSS_C_NO_CONTEXT;
177 ECB :
178 GIC 6 : return pg_GSS_continue(conn, payloadlen);
179 : }
180 : #endif /* ENABLE_GSS */
181 :
182 :
183 : #ifdef ENABLE_SSPI
184 : /*
185 : * SSPI authentication system (Windows only)
186 : */
187 :
188 : static void
189 : pg_SSPI_error(PGconn *conn, const char *mprefix, SECURITY_STATUS r)
190 : {
191 : char sysmsg[256];
192 :
193 : if (FormatMessage(FORMAT_MESSAGE_IGNORE_INSERTS |
194 : FORMAT_MESSAGE_FROM_SYSTEM,
195 : NULL, r, 0,
196 : sysmsg, sizeof(sysmsg), NULL) == 0)
197 : appendPQExpBuffer(&conn->errorMessage, "%s: SSPI error %x\n",
198 : mprefix, (unsigned int) r);
199 : else
200 : appendPQExpBuffer(&conn->errorMessage, "%s: %s (%x)\n",
201 : mprefix, sysmsg, (unsigned int) r);
202 : }
203 :
204 : /*
205 : * Continue SSPI authentication with next token as needed.
206 : */
207 : static int
208 : pg_SSPI_continue(PGconn *conn, int payloadlen)
209 : {
210 : SECURITY_STATUS r;
211 : CtxtHandle newContext;
212 : ULONG contextAttr;
213 : SecBufferDesc inbuf;
214 : SecBufferDesc outbuf;
215 : SecBuffer OutBuffers[1];
216 : SecBuffer InBuffers[1];
217 : char *inputbuf = NULL;
218 :
219 : if (conn->sspictx != NULL)
220 : {
221 : /*
222 : * On runs other than the first we have some data to send. Put this
223 : * data in a SecBuffer type structure.
224 : */
225 : inputbuf = malloc(payloadlen);
226 : if (!inputbuf)
227 : {
228 : libpq_append_conn_error(conn, "out of memory allocating SSPI buffer (%d)",
229 : payloadlen);
230 : return STATUS_ERROR;
231 : }
232 : if (pqGetnchar(inputbuf, payloadlen, conn))
233 : {
234 : /*
235 : * Shouldn't happen, because the caller should've ensured that the
236 : * whole message is already in the input buffer.
237 : */
238 : free(inputbuf);
239 : return STATUS_ERROR;
240 : }
241 :
242 : inbuf.ulVersion = SECBUFFER_VERSION;
243 : inbuf.cBuffers = 1;
244 : inbuf.pBuffers = InBuffers;
245 : InBuffers[0].pvBuffer = inputbuf;
246 : InBuffers[0].cbBuffer = payloadlen;
247 : InBuffers[0].BufferType = SECBUFFER_TOKEN;
248 : }
249 :
250 : OutBuffers[0].pvBuffer = NULL;
251 : OutBuffers[0].BufferType = SECBUFFER_TOKEN;
252 : OutBuffers[0].cbBuffer = 0;
253 : outbuf.cBuffers = 1;
254 : outbuf.pBuffers = OutBuffers;
255 : outbuf.ulVersion = SECBUFFER_VERSION;
256 :
257 : r = InitializeSecurityContext(conn->sspicred,
258 : conn->sspictx,
259 : conn->sspitarget,
260 : ISC_REQ_ALLOCATE_MEMORY,
261 : 0,
262 : SECURITY_NETWORK_DREP,
263 : (conn->sspictx == NULL) ? NULL : &inbuf,
264 : 0,
265 : &newContext,
266 : &outbuf,
267 : &contextAttr,
268 : NULL);
269 :
270 : /* we don't need the input anymore */
271 : free(inputbuf);
272 :
273 : if (r != SEC_E_OK && r != SEC_I_CONTINUE_NEEDED)
274 : {
275 : pg_SSPI_error(conn, libpq_gettext("SSPI continuation error"), r);
276 :
277 : return STATUS_ERROR;
278 : }
279 :
280 : if (conn->sspictx == NULL)
281 : {
282 : /* On first run, transfer retrieved context handle */
283 : conn->sspictx = malloc(sizeof(CtxtHandle));
284 : if (conn->sspictx == NULL)
285 : {
286 : libpq_append_conn_error(conn, "out of memory");
287 : return STATUS_ERROR;
288 : }
289 : memcpy(conn->sspictx, &newContext, sizeof(CtxtHandle));
290 : }
291 :
292 : /*
293 : * If SSPI returned any data to be sent to the server (as it normally
294 : * would), send this data as a password packet.
295 : */
296 : if (outbuf.cBuffers > 0)
297 : {
298 : if (outbuf.cBuffers != 1)
299 : {
300 : /*
301 : * This should never happen, at least not for Kerberos
302 : * authentication. Keep check in case it shows up with other
303 : * authentication methods later.
304 : */
305 : appendPQExpBufferStr(&conn->errorMessage,
306 : "SSPI returned invalid number of output buffers\n");
307 : return STATUS_ERROR;
308 : }
309 :
310 : /*
311 : * If the negotiation is complete, there may be zero bytes to send.
312 : * The server is at this point not expecting any more data, so don't
313 : * send it.
314 : */
315 : if (outbuf.pBuffers[0].cbBuffer > 0)
316 : {
317 : if (pqPacketSend(conn, 'p',
318 : outbuf.pBuffers[0].pvBuffer, outbuf.pBuffers[0].cbBuffer))
319 : {
320 : FreeContextBuffer(outbuf.pBuffers[0].pvBuffer);
321 : return STATUS_ERROR;
322 : }
323 : }
324 : FreeContextBuffer(outbuf.pBuffers[0].pvBuffer);
325 : }
326 :
327 : if (r == SEC_E_OK)
328 : conn->client_finished_auth = true;
329 :
330 : /* Cleanup is handled by the code in freePGconn() */
331 : return STATUS_OK;
332 : }
333 :
334 : /*
335 : * Send initial SSPI authentication token.
336 : * If use_negotiate is 0, use kerberos authentication package which is
337 : * compatible with Unix. If use_negotiate is 1, use the negotiate package
338 : * which supports both kerberos and NTLM, but is not compatible with Unix.
339 : */
340 : static int
341 : pg_SSPI_startup(PGconn *conn, int use_negotiate, int payloadlen)
342 : {
343 : SECURITY_STATUS r;
344 : TimeStamp expire;
345 : char *host = conn->connhost[conn->whichhost].host;
346 :
347 : if (conn->sspictx)
348 : {
349 : libpq_append_conn_error(conn, "duplicate SSPI authentication request");
350 : return STATUS_ERROR;
351 : }
352 :
353 : /*
354 : * Retrieve credentials handle
355 : */
356 : conn->sspicred = malloc(sizeof(CredHandle));
357 : if (conn->sspicred == NULL)
358 : {
359 : libpq_append_conn_error(conn, "out of memory");
360 : return STATUS_ERROR;
361 : }
362 :
363 : r = AcquireCredentialsHandle(NULL,
364 : use_negotiate ? "negotiate" : "kerberos",
365 : SECPKG_CRED_OUTBOUND,
366 : NULL,
367 : NULL,
368 : NULL,
369 : NULL,
370 : conn->sspicred,
371 : &expire);
372 : if (r != SEC_E_OK)
373 : {
374 : pg_SSPI_error(conn, libpq_gettext("could not acquire SSPI credentials"), r);
375 : free(conn->sspicred);
376 : conn->sspicred = NULL;
377 : return STATUS_ERROR;
378 : }
379 :
380 : /*
381 : * Compute target principal name. SSPI has a different format from GSSAPI,
382 : * but not more complex. We can skip the @REALM part, because Windows will
383 : * fill that in for us automatically.
384 : */
385 : if (!(host && host[0] != '\0'))
386 : {
387 : libpq_append_conn_error(conn, "host name must be specified");
388 : return STATUS_ERROR;
389 : }
390 : conn->sspitarget = malloc(strlen(conn->krbsrvname) + strlen(host) + 2);
391 : if (!conn->sspitarget)
392 : {
393 : libpq_append_conn_error(conn, "out of memory");
394 : return STATUS_ERROR;
395 : }
396 : sprintf(conn->sspitarget, "%s/%s", conn->krbsrvname, host);
397 :
398 : /*
399 : * Indicate that we're in SSPI authentication mode to make sure that
400 : * pg_SSPI_continue is called next time in the negotiation.
401 : */
402 : conn->usesspi = 1;
403 :
404 : return pg_SSPI_continue(conn, payloadlen);
405 : }
406 : #endif /* ENABLE_SSPI */
407 ECB :
408 : /*
409 : * Initialize SASL authentication exchange.
410 : */
411 : static int
412 GIC 35 : pg_SASL_init(PGconn *conn, int payloadlen)
413 : {
414 35 : char *initialresponse = NULL;
415 : int initialresponselen;
416 : bool done;
417 ECB : bool success;
418 : const char *selected_mechanism;
419 : PQExpBufferData mechanism_buf;
420 : char *password;
421 :
422 CBC 35 : initPQExpBuffer(&mechanism_buf);
423 ECB :
424 GIC 35 : if (conn->channel_binding[0] == 'r' && /* require */
425 4 : !conn->ssl_in_use)
426 ECB : {
427 GNC 1 : libpq_append_conn_error(conn, "channel binding required, but SSL not in use");
428 GBC 1 : goto error;
429 : }
430 :
431 GIC 34 : if (conn->sasl_state)
432 : {
433 UNC 0 : libpq_append_conn_error(conn, "duplicate SASL authentication request");
434 UIC 0 : goto error;
435 : }
436 ECB :
437 : /*
438 : * Parse the list of SASL authentication mechanisms in the
439 : * AuthenticationSASL message, and select the best mechanism that we
440 : * support. SCRAM-SHA-256-PLUS and SCRAM-SHA-256 are the only ones
441 EUB : * supported at the moment, listed by order of decreasing importance.
442 : */
443 GBC 34 : selected_mechanism = NULL;
444 : for (;;)
445 ECB : {
446 GBC 75 : if (pqGets(&mechanism_buf, conn))
447 : {
448 UIC 0 : appendPQExpBufferStr(&conn->errorMessage,
449 ECB : "fe_sendauth: invalid authentication request from server: invalid list of authentication mechanisms\n");
450 LBC 0 : goto error;
451 : }
452 GIC 75 : if (PQExpBufferDataBroken(mechanism_buf))
453 UIC 0 : goto oom_error;
454 :
455 : /* An empty string indicates end of list */
456 GIC 75 : if (mechanism_buf.data[0] == '\0')
457 34 : break;
458 :
459 ECB : /*
460 : * Select the mechanism to use. Pick SCRAM-SHA-256-PLUS over anything
461 : * else if a channel binding type is set and if the client supports it
462 : * (and did not set channel_binding=disable). Pick SCRAM-SHA-256 if
463 : * nothing else has already been picked. If we add more mechanisms, a
464 : * more refined priority mechanism might become necessary.
465 : */
466 GIC 41 : if (strcmp(mechanism_buf.data, SCRAM_SHA_256_PLUS_NAME) == 0)
467 : {
468 7 : if (conn->ssl_in_use)
469 : {
470 ECB : /* The server has offered SCRAM-SHA-256-PLUS. */
471 :
472 : #ifdef HAVE_PGTLS_GET_PEER_CERTIFICATE_HASH
473 : /*
474 : * The client supports channel binding, which is chosen if
475 : * channel_binding is not disabled.
476 : */
477 GIC 7 : if (conn->channel_binding[0] != 'd') /* disable */
478 : {
479 5 : selected_mechanism = SCRAM_SHA_256_PLUS_NAME;
480 5 : conn->sasl = &pg_scram_mech;
481 : }
482 : #else
483 : /*
484 : * The client does not support channel binding. If it is
485 : * required, complain immediately instead of the error below
486 : * which would be confusing as the server is publishing
487 : * SCRAM-SHA-256-PLUS.
488 : */
489 : if (conn->channel_binding[0] == 'r') /* require */
490 : {
491 : libpq_append_conn_error(conn, "channel binding is required, but client does not support it");
492 : goto error;
493 : }
494 : #endif
495 : }
496 : else
497 : {
498 : /*
499 EUB : * The server offered SCRAM-SHA-256-PLUS, but the connection
500 : * is not SSL-encrypted. That's not sane. Perhaps SSL was
501 : * stripped by a proxy? There's no point in continuing,
502 : * because the server will reject the connection anyway if we
503 ECB : * try authenticate without channel binding even though both
504 : * the client and server supported it. The SCRAM exchange
505 : * checks for that, to prevent downgrade attacks.
506 : */
507 UNC 0 : libpq_append_conn_error(conn, "server offered SCRAM-SHA-256-PLUS authentication over a non-SSL connection");
508 UIC 0 : goto error;
509 : }
510 ECB : }
511 GIC 34 : else if (strcmp(mechanism_buf.data, SCRAM_SHA_256_NAME) == 0 &&
512 EUB : !selected_mechanism)
513 : {
514 GIC 29 : selected_mechanism = SCRAM_SHA_256_NAME;
515 29 : conn->sasl = &pg_scram_mech;
516 ECB : }
517 : }
518 :
519 GBC 34 : if (!selected_mechanism)
520 EUB : {
521 UNC 0 : libpq_append_conn_error(conn, "none of the server's SASL authentication mechanisms are supported");
522 UIC 0 : goto error;
523 : }
524 :
525 GIC 34 : if (conn->channel_binding[0] == 'r' && /* require */
526 3 : strcmp(selected_mechanism, SCRAM_SHA_256_PLUS_NAME) != 0)
527 : {
528 UNC 0 : libpq_append_conn_error(conn, "channel binding is required, but server did not offer an authentication method that supports channel binding");
529 UIC 0 : goto error;
530 : }
531 ECB :
532 : /*
533 : * Now that the SASL mechanism has been chosen for the exchange,
534 : * initialize its state information.
535 : */
536 :
537 EUB : /*
538 : * First, select the password to use for the exchange, complaining if
539 : * there isn't one. Currently, all supported SASL mechanisms require a
540 : * password, so we can just go ahead here without further distinction.
541 : */
542 CBC 34 : conn->password_needed = true;
543 GIC 34 : password = conn->connhost[conn->whichhost].password;
544 34 : if (password == NULL)
545 34 : password = conn->pgpass;
546 34 : if (password == NULL || password[0] == '\0')
547 : {
548 UIC 0 : appendPQExpBufferStr(&conn->errorMessage,
549 : PQnoPasswordSupplied);
550 LBC 0 : goto error;
551 : }
552 :
553 CBC 34 : Assert(conn->sasl);
554 EUB :
555 : /*
556 : * Initialize the SASL state information with all the information gathered
557 ECB : * during the initial exchange.
558 : *
559 : * Note: Only tls-unique is supported for the moment.
560 : */
561 GIC 34 : conn->sasl_state = conn->sasl->init(conn,
562 ECB : password,
563 EUB : selected_mechanism);
564 GIC 34 : if (!conn->sasl_state)
565 UIC 0 : goto oom_error;
566 :
567 : /* Get the mechanism-specific Initial Client Response, if any */
568 CBC 34 : conn->sasl->exchange(conn->sasl_state,
569 EUB : NULL, -1,
570 ECB : &initialresponse, &initialresponselen,
571 EUB : &done, &success);
572 ECB :
573 GIC 34 : if (done && !success)
574 LBC 0 : goto error;
575 EUB :
576 ECB : /*
577 EUB : * Build a SASLInitialResponse message, and send it.
578 : */
579 CBC 34 : if (pqPutMsgStart('p', conn))
580 UBC 0 : goto error;
581 CBC 34 : if (pqPuts(selected_mechanism, conn))
582 UBC 0 : goto error;
583 GIC 34 : if (initialresponse)
584 ECB : {
585 CBC 34 : if (pqPutInt(initialresponselen, 4, conn))
586 UIC 0 : goto error;
587 CBC 34 : if (pqPutnchar(initialresponse, initialresponselen, conn))
588 UIC 0 : goto error;
589 ECB : }
590 CBC 34 : if (pqPutMsgEnd(conn))
591 LBC 0 : goto error;
592 CBC 34 : if (pqFlush(conn))
593 UIC 0 : goto error;
594 EUB :
595 GBC 34 : termPQExpBuffer(&mechanism_buf);
596 GNC 34 : free(initialresponse);
597 EUB :
598 GIC 34 : return STATUS_OK;
599 :
600 1 : error:
601 1 : termPQExpBuffer(&mechanism_buf);
602 GNC 1 : free(initialresponse);
603 GIC 1 : return STATUS_ERROR;
604 :
605 LBC 0 : oom_error:
606 UIC 0 : termPQExpBuffer(&mechanism_buf);
607 UNC 0 : free(initialresponse);
608 0 : libpq_append_conn_error(conn, "out of memory");
609 UIC 0 : return STATUS_ERROR;
610 : }
611 :
612 : /*
613 ECB : * Exchange a message for SASL communication protocol with the backend.
614 : * This should be used after calling pg_SASL_init to set up the status of
615 : * the protocol.
616 EUB : */
617 : static int
618 GBC 62 : pg_SASL_continue(PGconn *conn, int payloadlen, bool final)
619 : {
620 : char *output;
621 ECB : int outputlen;
622 : bool done;
623 EUB : bool success;
624 : int res;
625 : char *challenge;
626 :
627 ECB : /* Read the SASL challenge from the AuthenticationSASLContinue message. */
628 GIC 62 : challenge = malloc(payloadlen + 1);
629 CBC 62 : if (!challenge)
630 : {
631 UNC 0 : libpq_append_conn_error(conn, "out of memory allocating SASL buffer (%d)",
632 : payloadlen);
633 UIC 0 : return STATUS_ERROR;
634 ECB : }
635 :
636 GBC 62 : if (pqGetnchar(challenge, payloadlen, conn))
637 EUB : {
638 UIC 0 : free(challenge);
639 UBC 0 : return STATUS_ERROR;
640 EUB : }
641 : /* For safety and convenience, ensure the buffer is NULL-terminated. */
642 GIC 62 : challenge[payloadlen] = '\0';
643 :
644 62 : conn->sasl->exchange(conn->sasl_state,
645 : challenge, payloadlen,
646 : &output, &outputlen,
647 ECB : &done, &success);
648 GIC 62 : free(challenge); /* don't need the input anymore */
649 EUB :
650 GBC 62 : if (final && !done)
651 : {
652 UIC 0 : if (outputlen != 0)
653 0 : free(output);
654 :
655 UNC 0 : libpq_append_conn_error(conn, "AuthenticationSASLFinal received from server, but SASL authentication was not completed");
656 LBC 0 : return STATUS_ERROR;
657 : }
658 :
659 : /*
660 : * If the exchange is not completed yet, we need to make sure that the
661 ECB : * SASL mechanism has generated a message to send back.
662 : */
663 GIC 62 : if (output == NULL && !done)
664 ECB : {
665 UNC 0 : libpq_append_conn_error(conn, "no client response found after SASL exchange success");
666 UIC 0 : return STATUS_ERROR;
667 ECB : }
668 EUB :
669 : /*
670 ECB : * SASL allows zero-length responses, so this check uses "output" and not
671 : * "outputlen" to allow the case of an empty message.
672 : */
673 GIC 62 : if (output)
674 ECB : {
675 : /*
676 : * Send the SASL response to the server.
677 : */
678 GIC 34 : res = pqPacketSend(conn, 'p', output, outputlen);
679 34 : free(output);
680 :
681 34 : if (res != STATUS_OK)
682 LBC 0 : return STATUS_ERROR;
683 : }
684 ECB :
685 GBC 62 : if (done && !success)
686 UIC 0 : return STATUS_ERROR;
687 :
688 GIC 62 : return STATUS_OK;
689 : }
690 ECB :
691 EUB : static int
692 CBC 44 : pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
693 : {
694 : int ret;
695 44 : char *crypt_pwd = NULL;
696 : const char *pwd_to_send;
697 : char md5Salt[4];
698 EUB :
699 : /* Read the salt from the AuthenticationMD5Password message. */
700 GIC 44 : if (areq == AUTH_REQ_MD5)
701 : {
702 6 : if (pqGetnchar(md5Salt, 4, conn))
703 UIC 0 : return STATUS_ERROR; /* shouldn't happen */
704 : }
705 :
706 : /* Encrypt the password if needed. */
707 :
708 GIC 44 : switch (areq)
709 : {
710 6 : case AUTH_REQ_MD5:
711 : {
712 : char *crypt_pwd2;
713 6 : const char *errstr = NULL;
714 ECB :
715 : /* Allocate enough space for two MD5 hashes */
716 CBC 6 : crypt_pwd = malloc(2 * (MD5_PASSWD_LEN + 1));
717 6 : if (!crypt_pwd)
718 : {
719 UNC 0 : libpq_append_conn_error(conn, "out of memory");
720 UIC 0 : return STATUS_ERROR;
721 ECB : }
722 :
723 GIC 6 : crypt_pwd2 = crypt_pwd + MD5_PASSWD_LEN + 1;
724 6 : if (!pg_md5_encrypt(password, conn->pguser,
725 6 : strlen(conn->pguser), crypt_pwd2,
726 : &errstr))
727 : {
728 UNC 0 : libpq_append_conn_error(conn, "could not encrypt password: %s", errstr);
729 UBC 0 : free(crypt_pwd);
730 UIC 0 : return STATUS_ERROR;
731 ECB : }
732 GIC 6 : if (!pg_md5_encrypt(crypt_pwd2 + strlen("md5"), md5Salt,
733 ECB : 4, crypt_pwd, &errstr))
734 : {
735 UNC 0 : libpq_append_conn_error(conn, "could not encrypt password: %s", errstr);
736 UIC 0 : free(crypt_pwd);
737 0 : return STATUS_ERROR;
738 : }
739 :
740 GIC 6 : pwd_to_send = crypt_pwd;
741 CBC 6 : break;
742 : }
743 38 : case AUTH_REQ_PASSWORD:
744 GIC 38 : pwd_to_send = password;
745 CBC 38 : break;
746 UIC 0 : default:
747 0 : return STATUS_ERROR;
748 : }
749 GIC 44 : ret = pqPacketSend(conn, 'p', pwd_to_send, strlen(pwd_to_send) + 1);
750 GNC 44 : free(crypt_pwd);
751 GIC 44 : return ret;
752 : }
753 :
754 : /*
755 : * Translate a disallowed AuthRequest code into an error message.
756 : */
757 : static const char *
758 GNC 17 : auth_method_description(AuthRequest areq)
759 : {
760 17 : switch (areq)
761 : {
762 6 : case AUTH_REQ_PASSWORD:
763 6 : return libpq_gettext("server requested a cleartext password");
764 5 : case AUTH_REQ_MD5:
765 5 : return libpq_gettext("server requested a hashed password");
766 1 : case AUTH_REQ_GSS:
767 : case AUTH_REQ_GSS_CONT:
768 1 : return libpq_gettext("server requested GSSAPI authentication");
769 UNC 0 : case AUTH_REQ_SSPI:
770 0 : return libpq_gettext("server requested SSPI authentication");
771 GNC 5 : case AUTH_REQ_SASL:
772 : case AUTH_REQ_SASL_CONT:
773 : case AUTH_REQ_SASL_FIN:
774 5 : return libpq_gettext("server requested SASL authentication");
775 : }
776 :
777 UNC 0 : return libpq_gettext("server requested an unknown authentication type");
778 : }
779 :
780 : /*
781 : * Convenience macro for checking the allowed_auth_methods bitmask. Caller
782 : * must ensure that type is not greater than 31 (high bit of the bitmask).
783 : */
784 : #define auth_method_allowed(conn, type) \
785 : (((conn)->allowed_auth_methods & (1 << (type))) != 0)
786 :
787 : /*
788 : * Verify that the authentication request is expected, given the connection
789 : * parameters. This is especially important when the client wishes to
790 : * authenticate the server before any sensitive information is exchanged.
791 : */
792 : static bool
793 CBC 9077 : check_expected_areq(AuthRequest areq, PGconn *conn)
794 : {
795 GIC 9077 : bool result = true;
796 GNC 9077 : const char *reason = NULL;
797 :
798 : StaticAssertDecl((sizeof(conn->allowed_auth_methods) * CHAR_BIT) > AUTH_REQ_MAX,
799 : "AUTH_REQ_MAX overflows the allowed_auth_methods bitmask");
800 :
801 9077 : if (conn->sslcertmode[0] == 'r' /* require */
802 3 : && areq == AUTH_REQ_OK)
803 : {
804 : /*
805 : * Trade off a little bit of complexity to try to get these error
806 : * messages as precise as possible.
807 : */
808 3 : if (!conn->ssl_cert_requested)
809 : {
810 UNC 0 : libpq_append_conn_error(conn, "server did not request an SSL certificate");
811 0 : return false;
812 : }
813 GNC 3 : else if (!conn->ssl_cert_sent)
814 : {
815 1 : libpq_append_conn_error(conn, "server accepted connection without a valid SSL certificate");
816 1 : return false;
817 : }
818 : }
819 :
820 : /*
821 : * If the user required a specific auth method, or specified an allowed
822 : * set, then reject all others here, and make sure the server actually
823 : * completes an authentication exchange.
824 : */
825 9076 : if (conn->require_auth)
826 : {
827 74 : switch (areq)
828 : {
829 32 : case AUTH_REQ_OK:
830 :
831 : /*
832 : * Check to make sure we've actually finished our exchange (or
833 : * else that the user has allowed an authentication-less
834 : * connection).
835 : *
836 : * If the user has allowed both SCRAM and unauthenticated
837 : * (trust) connections, then this check will silently accept
838 : * partial SCRAM exchanges, where a misbehaving server does
839 : * not provide its verifier before sending an OK. This is
840 : * consistent with historical behavior, but it may be a point
841 : * to revisit in the future, since it could allow a server
842 : * that doesn't know the user's password to silently harvest
843 : * material for a brute force attack.
844 : */
845 32 : if (!conn->auth_required || conn->client_finished_auth)
846 : break;
847 :
848 : /*
849 : * No explicit authentication request was made by the server
850 : * -- or perhaps it was made and not completed, in the case of
851 : * SCRAM -- but there is one special case to check. If the
852 : * user allowed "gss", then a GSS-encrypted channel also
853 : * satisfies the check.
854 : */
855 : #ifdef ENABLE_GSS
856 11 : if (auth_method_allowed(conn, AUTH_REQ_GSS) && conn->gssenc)
857 : {
858 : /*
859 : * If implicit GSS auth has already been performed via GSS
860 : * encryption, we don't need to have performed an
861 : * AUTH_REQ_GSS exchange. This allows require_auth=gss to
862 : * be combined with gssencmode, since there won't be an
863 : * explicit authentication request in that case.
864 : */
865 : }
866 : else
867 : #endif
868 : {
869 8 : reason = libpq_gettext("server did not complete authentication");
870 8 : result = false;
871 : }
872 :
873 11 : break;
874 :
875 42 : case AUTH_REQ_PASSWORD:
876 : case AUTH_REQ_MD5:
877 : case AUTH_REQ_GSS:
878 : case AUTH_REQ_GSS_CONT:
879 : case AUTH_REQ_SSPI:
880 : case AUTH_REQ_SASL:
881 : case AUTH_REQ_SASL_CONT:
882 : case AUTH_REQ_SASL_FIN:
883 :
884 : /*
885 : * We don't handle these with the default case, to avoid
886 : * bit-shifting past the end of the allowed_auth_methods mask
887 : * if the server sends an unexpected AuthRequest.
888 : */
889 42 : result = auth_method_allowed(conn, areq);
890 42 : break;
891 :
892 UNC 0 : default:
893 0 : result = false;
894 0 : break;
895 : }
896 : }
897 :
898 GNC 9076 : if (!result)
899 : {
900 25 : if (!reason)
901 17 : reason = auth_method_description(areq);
902 :
903 25 : libpq_append_conn_error(conn, "auth method \"%s\" requirement failed: %s",
904 : conn->require_auth, reason);
905 25 : return result;
906 : }
907 :
908 : /*
909 : * When channel_binding=require, we must protect against two cases: (1) we
910 : * must not respond to non-SASL authentication requests, which might leak
911 : * information such as the client's password; and (2) even if we receive
912 : * AUTH_REQ_OK, we still must ensure that channel binding has happened in
913 : * order to authenticate the server.
914 : */
915 CBC 9051 : if (conn->channel_binding[0] == 'r' /* require */ )
916 : {
917 GIC 17 : switch (areq)
918 : {
919 10 : case AUTH_REQ_SASL:
920 : case AUTH_REQ_SASL_CONT:
921 : case AUTH_REQ_SASL_FIN:
922 10 : break;
923 4 : case AUTH_REQ_OK:
924 4 : if (!conn->sasl || !conn->sasl->channel_bound(conn->sasl_state))
925 : {
926 GNC 1 : libpq_append_conn_error(conn, "channel binding required, but server authenticated client without channel binding");
927 CBC 1 : result = false;
928 ECB : }
929 GIC 4 : break;
930 3 : default:
931 GNC 3 : libpq_append_conn_error(conn, "channel binding required but not supported by server's authentication request");
932 CBC 3 : result = false;
933 GIC 3 : break;
934 : }
935 : }
936 :
937 9051 : return result;
938 : }
939 :
940 : /*
941 : * pg_fe_sendauth
942 : * client demux routine for processing an authentication request
943 : *
944 : * The server has sent us an authentication challenge (or OK). Send an
945 : * appropriate response. The caller has ensured that the whole message is
946 ECB : * now in the input buffer, and has already read the type and length of
947 : * it. We are responsible for reading any remaining extra data, specific
948 : * to the authentication method. 'payloadlen' is the remaining length in
949 EUB : * the message.
950 : */
951 : int
952 GIC 9077 : pg_fe_sendauth(AuthRequest areq, int payloadlen, PGconn *conn)
953 : {
954 : int oldmsglen;
955 ECB :
956 GIC 9077 : if (!check_expected_areq(areq, conn))
957 CBC 30 : return STATUS_ERROR;
958 ECB :
959 GIC 9047 : switch (areq)
960 ECB : {
961 GIC 8894 : case AUTH_REQ_OK:
962 CBC 8894 : break;
963 :
964 UIC 0 : case AUTH_REQ_KRB4:
965 UNC 0 : libpq_append_conn_error(conn, "Kerberos 4 authentication not supported");
966 UIC 0 : return STATUS_ERROR;
967 :
968 0 : case AUTH_REQ_KRB5:
969 UNC 0 : libpq_append_conn_error(conn, "Kerberos 5 authentication not supported");
970 LBC 0 : return STATUS_ERROR;
971 :
972 ECB : #if defined(ENABLE_GSS) || defined(ENABLE_SSPI)
973 GIC 6 : case AUTH_REQ_GSS:
974 ECB : #if !defined(ENABLE_SSPI)
975 : /* no native SSPI, so use GSSAPI library for it */
976 : case AUTH_REQ_SSPI:
977 : #endif
978 : {
979 : int r;
980 :
981 CBC 6 : pglock_thread();
982 ECB :
983 : /*
984 : * If we have both GSS and SSPI support compiled in, use SSPI
985 : * support by default. This is overridable by a connection
986 : * string parameter. Note that when using SSPI we still leave
987 : * the negotiate parameter off, since we want SSPI to use the
988 : * GSSAPI kerberos protocol. For actual SSPI negotiate
989 : * protocol, we use AUTH_REQ_SSPI.
990 : */
991 : #if defined(ENABLE_GSS) && defined(ENABLE_SSPI)
992 : if (conn->gsslib && (pg_strcasecmp(conn->gsslib, "gssapi") == 0))
993 : r = pg_GSS_startup(conn, payloadlen);
994 : else
995 : r = pg_SSPI_startup(conn, 0, payloadlen);
996 : #elif defined(ENABLE_GSS) && !defined(ENABLE_SSPI)
997 GIC 6 : r = pg_GSS_startup(conn, payloadlen);
998 : #elif !defined(ENABLE_GSS) && defined(ENABLE_SSPI)
999 : r = pg_SSPI_startup(conn, 0, payloadlen);
1000 : #endif
1001 6 : if (r != STATUS_OK)
1002 : {
1003 : /* Error message already filled in. */
1004 1 : pgunlock_thread();
1005 1 : return STATUS_ERROR;
1006 : }
1007 CBC 5 : pgunlock_thread();
1008 : }
1009 GIC 5 : break;
1010 :
1011 CBC 5 : case AUTH_REQ_GSS_CONT:
1012 ECB : {
1013 : int r;
1014 :
1015 GIC 5 : pglock_thread();
1016 ECB : #if defined(ENABLE_GSS) && defined(ENABLE_SSPI)
1017 : if (conn->usesspi)
1018 : r = pg_SSPI_continue(conn, payloadlen);
1019 EUB : else
1020 : r = pg_GSS_continue(conn, payloadlen);
1021 : #elif defined(ENABLE_GSS) && !defined(ENABLE_SSPI)
1022 GIC 5 : r = pg_GSS_continue(conn, payloadlen);
1023 EUB : #elif !defined(ENABLE_GSS) && defined(ENABLE_SSPI)
1024 : r = pg_SSPI_continue(conn, payloadlen);
1025 : #endif
1026 GIC 5 : if (r != STATUS_OK)
1027 : {
1028 ECB : /* Error message already filled in. */
1029 UIC 0 : pgunlock_thread();
1030 0 : return STATUS_ERROR;
1031 : }
1032 GIC 5 : pgunlock_thread();
1033 : }
1034 5 : break;
1035 : #else /* defined(ENABLE_GSS) || defined(ENABLE_SSPI) */
1036 ECB : /* No GSSAPI *or* SSPI support */
1037 : case AUTH_REQ_GSS:
1038 : case AUTH_REQ_GSS_CONT:
1039 : libpq_append_conn_error(conn, "GSSAPI authentication not supported");
1040 : return STATUS_ERROR;
1041 : #endif /* defined(ENABLE_GSS) || defined(ENABLE_SSPI) */
1042 :
1043 : #ifdef ENABLE_SSPI
1044 : case AUTH_REQ_SSPI:
1045 :
1046 : /*
1047 : * SSPI has its own startup message so libpq can decide which
1048 : * method to use. Indicate to pg_SSPI_startup that we want SSPI
1049 : * negotiation instead of Kerberos.
1050 : */
1051 : pglock_thread();
1052 : if (pg_SSPI_startup(conn, 1, payloadlen) != STATUS_OK)
1053 : {
1054 : /* Error message already filled in. */
1055 : pgunlock_thread();
1056 : return STATUS_ERROR;
1057 : }
1058 : pgunlock_thread();
1059 : break;
1060 : #else
1061 :
1062 : /*
1063 : * No SSPI support. However, if we have GSSAPI but not SSPI
1064 : * support, AUTH_REQ_SSPI will have been handled in the codepath
1065 : * for AUTH_REQ_GSS above, so don't duplicate the case label in
1066 : * that case.
1067 : */
1068 : #if !defined(ENABLE_GSS)
1069 : case AUTH_REQ_SSPI:
1070 : libpq_append_conn_error(conn, "SSPI authentication not supported");
1071 : return STATUS_ERROR;
1072 : #endif /* !define(ENABLE_GSS) */
1073 : #endif /* ENABLE_SSPI */
1074 :
1075 :
1076 UIC 0 : case AUTH_REQ_CRYPT:
1077 UNC 0 : libpq_append_conn_error(conn, "Crypt authentication not supported");
1078 LBC 0 : return STATUS_ERROR;
1079 :
1080 GIC 45 : case AUTH_REQ_MD5:
1081 EUB : case AUTH_REQ_PASSWORD:
1082 : {
1083 : char *password;
1084 ECB :
1085 GIC 45 : conn->password_needed = true;
1086 CBC 45 : password = conn->connhost[conn->whichhost].password;
1087 GIC 45 : if (password == NULL)
1088 40 : password = conn->pgpass;
1089 45 : if (password == NULL || password[0] == '\0')
1090 : {
1091 1 : appendPQExpBufferStr(&conn->errorMessage,
1092 : PQnoPasswordSupplied);
1093 1 : return STATUS_ERROR;
1094 : }
1095 44 : if (pg_password_sendauth(conn, password, areq) != STATUS_OK)
1096 : {
1097 UIC 0 : appendPQExpBufferStr(&conn->errorMessage,
1098 : "fe_sendauth: error sending password authentication\n");
1099 0 : return STATUS_ERROR;
1100 : }
1101 :
1102 : /* We expect no further authentication requests. */
1103 GNC 44 : conn->client_finished_auth = true;
1104 GIC 44 : break;
1105 : }
1106 :
1107 35 : case AUTH_REQ_SASL:
1108 :
1109 : /*
1110 : * The request contains the name (as assigned by IANA) of the
1111 : * authentication mechanism.
1112 : */
1113 35 : if (pg_SASL_init(conn, payloadlen) != STATUS_OK)
1114 : {
1115 : /* pg_SASL_init already set the error message */
1116 1 : return STATUS_ERROR;
1117 : }
1118 34 : break;
1119 :
1120 62 : case AUTH_REQ_SASL_CONT:
1121 : case AUTH_REQ_SASL_FIN:
1122 62 : if (conn->sasl_state == NULL)
1123 : {
1124 UIC 0 : appendPQExpBufferStr(&conn->errorMessage,
1125 : "fe_sendauth: invalid authentication request from server: AUTH_REQ_SASL_CONT without AUTH_REQ_SASL\n");
1126 0 : return STATUS_ERROR;
1127 : }
1128 GIC 62 : oldmsglen = conn->errorMessage.len;
1129 62 : if (pg_SASL_continue(conn, payloadlen,
1130 : (areq == AUTH_REQ_SASL_FIN)) != STATUS_OK)
1131 EUB : {
1132 : /* Use this message if pg_SASL_continue didn't supply one */
1133 UBC 0 : if (conn->errorMessage.len == oldmsglen)
1134 UIC 0 : appendPQExpBufferStr(&conn->errorMessage,
1135 ECB : "fe_sendauth: error in SASL authentication\n");
1136 UIC 0 : return STATUS_ERROR;
1137 : }
1138 GIC 62 : break;
1139 :
1140 UIC 0 : default:
1141 UNC 0 : libpq_append_conn_error(conn, "authentication method %u not supported", areq);
1142 LBC 0 : return STATUS_ERROR;
1143 : }
1144 ECB :
1145 GIC 9044 : return STATUS_OK;
1146 EUB : }
1147 :
1148 :
1149 : /*
1150 : * pg_fe_getusername
1151 : *
1152 ECB : * Returns a pointer to malloc'd space containing the name of the
1153 : * specified user_id. If there is an error, return NULL, and append
1154 : * a suitable error message to *errorMessage if that's not NULL.
1155 : *
1156 : * Caution: on Windows, the user_id argument is ignored, and we always
1157 : * fetch the current user's name.
1158 : */
1159 : char *
1160 GIC 8660 : pg_fe_getusername(uid_t user_id, PQExpBuffer errorMessage)
1161 : {
1162 CBC 8660 : char *result = NULL;
1163 GIC 8660 : const char *name = NULL;
1164 :
1165 ECB : #ifdef WIN32
1166 : /* Microsoft recommends buffer size of UNLEN+1, where UNLEN = 256 */
1167 : char username[256 + 1];
1168 : DWORD namesize = sizeof(username);
1169 : #else
1170 : char pwdbuf[BUFSIZ];
1171 : #endif
1172 :
1173 EUB : /*
1174 : * Some users are using configure --enable-thread-safety-force, so we
1175 : * might as well do the locking within our library to protect getpwuid().
1176 : * In fact, application developers can use getpwuid() in their application
1177 ECB : * if they use the locking call we provide, or install their own locking
1178 : * function using PQregisterThreadLock().
1179 : */
1180 GIC 8660 : pglock_thread();
1181 :
1182 EUB : #ifdef WIN32
1183 : if (GetUserName(username, &namesize))
1184 : name = username;
1185 : else if (errorMessage)
1186 : libpq_append_error(errorMessage,
1187 : "user name lookup failure: error code %lu",
1188 : GetLastError());
1189 : #else
1190 GBC 8660 : if (pg_get_user_name(user_id, pwdbuf, sizeof(pwdbuf)))
1191 8660 : name = pwdbuf;
1192 UIC 0 : else if (errorMessage)
1193 0 : appendPQExpBuffer(errorMessage, "%s\n", pwdbuf);
1194 ECB : #endif
1195 :
1196 GIC 8660 : if (name)
1197 : {
1198 8660 : result = strdup(name);
1199 8660 : if (result == NULL && errorMessage)
1200 UNC 0 : libpq_append_error(errorMessage, "out of memory");
1201 : }
1202 :
1203 GIC 8660 : pgunlock_thread();
1204 :
1205 8660 : return result;
1206 : }
1207 :
1208 ECB : /*
1209 : * pg_fe_getauthname
1210 : *
1211 : * Returns a pointer to malloc'd space containing whatever name the user
1212 : * has authenticated to the system. If there is an error, return NULL,
1213 : * and append a suitable error message to *errorMessage if that's not NULL.
1214 : */
1215 : char *
1216 GIC 8660 : pg_fe_getauthname(PQExpBuffer errorMessage)
1217 : {
1218 : #ifdef WIN32
1219 : return pg_fe_getusername(0, errorMessage);
1220 : #else
1221 8660 : return pg_fe_getusername(geteuid(), errorMessage);
1222 : #endif
1223 : }
1224 :
1225 :
1226 : /*
1227 : * PQencryptPassword -- exported routine to encrypt a password with MD5
1228 ECB : *
1229 : * This function is equivalent to calling PQencryptPasswordConn with
1230 : * "md5" as the encryption method, except that this doesn't require
1231 : * a connection object. This function is deprecated, use
1232 : * PQencryptPasswordConn instead.
1233 : */
1234 : char *
1235 UIC 0 : PQencryptPassword(const char *passwd, const char *user)
1236 : {
1237 : char *crypt_pwd;
1238 LBC 0 : const char *errstr = NULL;
1239 ECB :
1240 UBC 0 : crypt_pwd = malloc(MD5_PASSWD_LEN + 1);
1241 0 : if (!crypt_pwd)
1242 UIC 0 : return NULL;
1243 :
1244 LBC 0 : if (!pg_md5_encrypt(passwd, user, strlen(user), crypt_pwd, &errstr))
1245 : {
1246 0 : free(crypt_pwd);
1247 0 : return NULL;
1248 EUB : }
1249 :
1250 UIC 0 : return crypt_pwd;
1251 ECB : }
1252 :
1253 : /*
1254 : * PQencryptPasswordConn -- exported routine to encrypt a password
1255 : *
1256 : * This is intended to be used by client applications that wish to send
1257 : * commands like ALTER USER joe PASSWORD 'pwd'. The password need not
1258 : * be sent in cleartext if it is encrypted on the client side. This is
1259 : * good because it ensures the cleartext password won't end up in logs,
1260 : * pg_stat displays, etc. We export the function so that clients won't
1261 : * be dependent on low-level details like whether the encryption is MD5
1262 : * or something else.
1263 : *
1264 : * Arguments are a connection object, the cleartext password, the SQL
1265 : * name of the user it is for, and a string indicating the algorithm to
1266 : * use for encrypting the password. If algorithm is NULL, this queries
1267 : * the server for the current 'password_encryption' value. If you wish
1268 : * to avoid that, e.g. to avoid blocking, you can execute
1269 : * 'show password_encryption' yourself before calling this function, and
1270 : * pass it as the algorithm.
1271 : *
1272 : * Return value is a malloc'd string. The client may assume the string
1273 : * doesn't contain any special characters that would require escaping.
1274 : * On error, an error message is stored in the connection object, and
1275 : * returns NULL.
1276 : */
1277 : char *
1278 GIC 1 : PQencryptPasswordConn(PGconn *conn, const char *passwd, const char *user,
1279 : const char *algorithm)
1280 : {
1281 : #define MAX_ALGORITHM_NAME_LEN 50
1282 : char algobuf[MAX_ALGORITHM_NAME_LEN + 1];
1283 GBC 1 : char *crypt_pwd = NULL;
1284 :
1285 GIC 1 : if (!conn)
1286 UBC 0 : return NULL;
1287 :
1288 GBC 1 : pqClearConnErrorState(conn);
1289 EUB :
1290 : /* If no algorithm was given, ask the server. */
1291 GIC 1 : if (algorithm == NULL)
1292 EUB : {
1293 : PGresult *res;
1294 : char *val;
1295 :
1296 GIC 1 : res = PQexec(conn, "show password_encryption");
1297 1 : if (res == NULL)
1298 EUB : {
1299 : /* PQexec() should've set conn->errorMessage already */
1300 UIC 0 : return NULL;
1301 : }
1302 GIC 1 : if (PQresultStatus(res) != PGRES_TUPLES_OK)
1303 : {
1304 : /* PQexec() should've set conn->errorMessage already */
1305 UIC 0 : PQclear(res);
1306 0 : return NULL;
1307 : }
1308 GIC 1 : if (PQntuples(res) != 1 || PQnfields(res) != 1)
1309 : {
1310 UIC 0 : PQclear(res);
1311 UNC 0 : libpq_append_conn_error(conn, "unexpected shape of result set returned for SHOW");
1312 UIC 0 : return NULL;
1313 : }
1314 GIC 1 : val = PQgetvalue(res, 0, 0);
1315 :
1316 1 : if (strlen(val) > MAX_ALGORITHM_NAME_LEN)
1317 : {
1318 UIC 0 : PQclear(res);
1319 UNC 0 : libpq_append_conn_error(conn, "password_encryption value too long");
1320 UIC 0 : return NULL;
1321 : }
1322 GIC 1 : strcpy(algobuf, val);
1323 1 : PQclear(res);
1324 ECB :
1325 GIC 1 : algorithm = algobuf;
1326 : }
1327 :
1328 : /*
1329 ECB : * Also accept "on" and "off" as aliases for "md5", because
1330 : * password_encryption was a boolean before PostgreSQL 10. We refuse to
1331 : * send the password in plaintext even if it was "off".
1332 EUB : */
1333 GIC 1 : if (strcmp(algorithm, "on") == 0 ||
1334 CBC 1 : strcmp(algorithm, "off") == 0)
1335 UIC 0 : algorithm = "md5";
1336 :
1337 ECB : /*
1338 : * Ok, now we know what algorithm to use
1339 : */
1340 GIC 1 : if (strcmp(algorithm, "scram-sha-256") == 0)
1341 : {
1342 CBC 1 : const char *errstr = NULL;
1343 ECB :
1344 GNC 1 : crypt_pwd = pg_fe_scram_build_secret(passwd,
1345 : conn->scram_sha_256_iterations,
1346 : &errstr);
1347 GIC 1 : if (!crypt_pwd)
1348 UNC 0 : libpq_append_conn_error(conn, "could not encrypt password: %s", errstr);
1349 : }
1350 UIC 0 : else if (strcmp(algorithm, "md5") == 0)
1351 EUB : {
1352 UBC 0 : crypt_pwd = malloc(MD5_PASSWD_LEN + 1);
1353 UIC 0 : if (crypt_pwd)
1354 ECB : {
1355 UIC 0 : const char *errstr = NULL;
1356 EUB :
1357 UBC 0 : if (!pg_md5_encrypt(passwd, user, strlen(user), crypt_pwd, &errstr))
1358 EUB : {
1359 UNC 0 : libpq_append_conn_error(conn, "could not encrypt password: %s", errstr);
1360 LBC 0 : free(crypt_pwd);
1361 UIC 0 : crypt_pwd = NULL;
1362 EUB : }
1363 : }
1364 : else
1365 UNC 0 : libpq_append_conn_error(conn, "out of memory");
1366 ECB : }
1367 : else
1368 : {
1369 UNC 0 : libpq_append_conn_error(conn, "unrecognized password encryption algorithm \"%s\"",
1370 : algorithm);
1371 UIC 0 : return NULL;
1372 : }
1373 :
1374 GIC 1 : return crypt_pwd;
1375 ECB : }
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