TLA Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * fe-secure-gssapi.c
4 : * The front-end (client) encryption support for GSSAPI
5 : *
6 : * Portions Copyright (c) 2016-2023, PostgreSQL Global Development Group
7 : *
8 : * IDENTIFICATION
9 : * src/interfaces/libpq/fe-secure-gssapi.c
10 : *
11 : *-------------------------------------------------------------------------
12 : */
13 :
14 : #include "postgres_fe.h"
15 :
16 : #include "fe-gssapi-common.h"
17 : #include "libpq-fe.h"
18 : #include "libpq-int.h"
19 : #include "port/pg_bswap.h"
20 :
21 :
22 : /*
23 : * Require encryption support, as well as mutual authentication and
24 : * tamperproofing measures.
25 : */
26 : #define GSS_REQUIRED_FLAGS GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG | \
27 : GSS_C_SEQUENCE_FLAG | GSS_C_CONF_FLAG | GSS_C_INTEG_FLAG
28 :
29 : /*
30 : * Handle the encryption/decryption of data using GSSAPI.
31 : *
32 : * In the encrypted data stream on the wire, we break up the data
33 : * into packets where each packet starts with a uint32-size length
34 : * word (in network byte order), then encrypted data of that length
35 : * immediately following. Decryption yields the same data stream
36 : * that would appear when not using encryption.
37 : *
38 : * Encrypted data typically ends up being larger than the same data
39 : * unencrypted, so we use fixed-size buffers for handling the
40 : * encryption/decryption which are larger than PQComm's buffer will
41 : * typically be to minimize the times where we have to make multiple
42 : * packets (and therefore multiple recv/send calls for a single
43 : * read/write call to us).
44 : *
45 : * NOTE: The client and server have to agree on the max packet size,
46 : * because we have to pass an entire packet to GSSAPI at a time and we
47 : * don't want the other side to send arbitrarily huge packets as we
48 : * would have to allocate memory for them to then pass them to GSSAPI.
49 : *
50 : * Therefore, these two #define's are effectively part of the protocol
51 : * spec and can't ever be changed.
52 : */
53 : #define PQ_GSS_SEND_BUFFER_SIZE 16384
54 : #define PQ_GSS_RECV_BUFFER_SIZE 16384
55 :
56 : /*
57 : * We need these state variables per-connection. To allow the functions
58 : * in this file to look mostly like those in be-secure-gssapi.c, set up
59 : * these macros.
60 : */
61 : #define PqGSSSendBuffer (conn->gss_SendBuffer)
62 : #define PqGSSSendLength (conn->gss_SendLength)
63 : #define PqGSSSendNext (conn->gss_SendNext)
64 : #define PqGSSSendConsumed (conn->gss_SendConsumed)
65 : #define PqGSSRecvBuffer (conn->gss_RecvBuffer)
66 : #define PqGSSRecvLength (conn->gss_RecvLength)
67 : #define PqGSSResultBuffer (conn->gss_ResultBuffer)
68 : #define PqGSSResultLength (conn->gss_ResultLength)
69 : #define PqGSSResultNext (conn->gss_ResultNext)
70 : #define PqGSSMaxPktSize (conn->gss_MaxPktSize)
71 :
72 :
73 : /*
74 : * Attempt to write len bytes of data from ptr to a GSSAPI-encrypted connection.
75 : *
76 : * The connection must be already set up for GSSAPI encryption (i.e., GSSAPI
77 : * transport negotiation is complete).
78 : *
79 : * On success, returns the number of data bytes consumed (possibly less than
80 : * len). On failure, returns -1 with errno set appropriately. If the errno
81 : * indicates a non-retryable error, a message is added to conn->errorMessage.
82 : * For retryable errors, caller should call again (passing the same data)
83 : * once the socket is ready.
84 : */
85 : ssize_t
86 CBC 122 : pg_GSS_write(PGconn *conn, const void *ptr, size_t len)
87 : {
88 : OM_uint32 major,
89 : minor;
90 : gss_buffer_desc input,
91 122 : output = GSS_C_EMPTY_BUFFER;
92 122 : ssize_t ret = -1;
93 122 : size_t bytes_sent = 0;
94 : size_t bytes_to_encrypt;
95 : size_t bytes_encrypted;
96 122 : gss_ctx_id_t gctx = conn->gctx;
97 :
98 : /*
99 : * When we get a failure, we must not tell the caller we have successfully
100 : * transmitted everything, else it won't retry. Hence a "success"
101 : * (positive) return value must only count source bytes corresponding to
102 : * fully-transmitted encrypted packets. The amount of source data
103 : * corresponding to the current partly-transmitted packet is remembered in
104 : * PqGSSSendConsumed. On a retry, the caller *must* be sending that data
105 : * again, so if it offers a len less than that, something is wrong.
106 : */
107 122 : if (len < PqGSSSendConsumed)
108 : {
109 UBC 0 : appendPQExpBufferStr(&conn->errorMessage,
110 : "GSSAPI caller failed to retransmit all data needing to be retried\n");
111 0 : errno = EINVAL;
112 0 : return -1;
113 : }
114 :
115 : /* Discount whatever source data we already encrypted. */
116 CBC 122 : bytes_to_encrypt = len - PqGSSSendConsumed;
117 122 : bytes_encrypted = PqGSSSendConsumed;
118 :
119 : /*
120 : * Loop through encrypting data and sending it out until it's all done or
121 : * pqsecure_raw_write() complains (which would likely mean that the socket
122 : * is non-blocking and the requested send() would block, or there was some
123 : * kind of actual error).
124 : */
125 244 : while (bytes_to_encrypt || PqGSSSendLength)
126 : {
127 244 : int conf_state = 0;
128 : uint32 netlen;
129 :
130 : /*
131 : * Check if we have data in the encrypted output buffer that needs to
132 : * be sent (possibly left over from a previous call), and if so, try
133 : * to send it. If we aren't able to, return that fact back up to the
134 : * caller.
135 : */
136 244 : if (PqGSSSendLength)
137 : {
138 : ssize_t retval;
139 122 : ssize_t amount = PqGSSSendLength - PqGSSSendNext;
140 :
141 GNC 122 : retval = pqsecure_raw_write(conn, PqGSSSendBuffer + PqGSSSendNext, amount);
142 122 : if (retval <= 0)
143 : {
144 : /*
145 : * Report any previously-sent data; if there was none, reflect
146 : * the pqsecure_raw_write result up to our caller. When there
147 : * was some, we're effectively assuming that any interesting
148 : * failure condition will recur on the next try.
149 : */
150 UBC 0 : if (bytes_sent)
151 0 : return bytes_sent;
152 UNC 0 : return retval;
153 : }
154 :
155 : /*
156 : * Check if this was a partial write, and if so, move forward that
157 : * far in our buffer and try again.
158 : */
159 GNC 122 : if (retval != amount)
160 : {
161 UNC 0 : PqGSSSendNext += retval;
162 UBC 0 : continue;
163 : }
164 :
165 : /* We've successfully sent whatever data was in that packet. */
166 CBC 122 : bytes_sent += PqGSSSendConsumed;
167 :
168 : /* All encrypted data was sent, our buffer is empty now. */
169 122 : PqGSSSendLength = PqGSSSendNext = PqGSSSendConsumed = 0;
170 : }
171 :
172 : /*
173 : * Check if there are any bytes left to encrypt. If not, we're done.
174 : */
175 244 : if (!bytes_to_encrypt)
176 122 : break;
177 :
178 : /*
179 : * Check how much we are being asked to send, if it's too much, then
180 : * we will have to loop and possibly be called multiple times to get
181 : * through all the data.
182 : */
183 122 : if (bytes_to_encrypt > PqGSSMaxPktSize)
184 UBC 0 : input.length = PqGSSMaxPktSize;
185 : else
186 CBC 122 : input.length = bytes_to_encrypt;
187 :
188 122 : input.value = (char *) ptr + bytes_encrypted;
189 :
190 122 : output.value = NULL;
191 122 : output.length = 0;
192 :
193 : /*
194 : * Create the next encrypted packet. Any failure here is considered a
195 : * hard failure, so we return -1 even if bytes_sent > 0.
196 : */
197 122 : major = gss_wrap(&minor, gctx, 1, GSS_C_QOP_DEFAULT,
198 : &input, &conf_state, &output);
199 122 : if (major != GSS_S_COMPLETE)
200 : {
201 UBC 0 : pg_GSS_error(libpq_gettext("GSSAPI wrap error"), conn, major, minor);
202 0 : errno = EIO; /* for lack of a better idea */
203 0 : goto cleanup;
204 : }
205 :
206 CBC 122 : if (conf_state == 0)
207 : {
208 UNC 0 : libpq_append_conn_error(conn, "outgoing GSSAPI message would not use confidentiality");
209 UBC 0 : errno = EIO; /* for lack of a better idea */
210 UIC 0 : goto cleanup;
211 : }
212 ECB :
213 GIC 122 : if (output.length > PQ_GSS_SEND_BUFFER_SIZE - sizeof(uint32))
214 EUB : {
215 UNC 0 : libpq_append_conn_error(conn, "client tried to send oversize GSSAPI packet (%zu > %zu)",
216 UBC 0 : (size_t) output.length,
217 EUB : PQ_GSS_SEND_BUFFER_SIZE - sizeof(uint32));
218 UIC 0 : errno = EIO; /* for lack of a better idea */
219 0 : goto cleanup;
220 ECB : }
221 :
222 CBC 122 : bytes_encrypted += input.length;
223 GIC 122 : bytes_to_encrypt -= input.length;
224 122 : PqGSSSendConsumed += input.length;
225 ECB :
226 : /* 4 network-order bytes of length, then payload */
227 CBC 122 : netlen = pg_hton32(output.length);
228 GIC 122 : memcpy(PqGSSSendBuffer + PqGSSSendLength, &netlen, sizeof(uint32));
229 CBC 122 : PqGSSSendLength += sizeof(uint32);
230 ECB :
231 GIC 122 : memcpy(PqGSSSendBuffer + PqGSSSendLength, output.value, output.length);
232 122 : PqGSSSendLength += output.length;
233 ECB :
234 : /* Release buffer storage allocated by GSSAPI */
235 GIC 122 : gss_release_buffer(&minor, &output);
236 : }
237 ECB :
238 : /* If we get here, our counters should all match up. */
239 GIC 122 : Assert(bytes_sent == len);
240 CBC 122 : Assert(bytes_sent == bytes_encrypted);
241 :
242 122 : ret = bytes_sent;
243 :
244 122 : cleanup:
245 EUB : /* Release GSSAPI buffer storage, if we didn't already */
246 CBC 122 : if (output.value != NULL)
247 UIC 0 : gss_release_buffer(&minor, &output);
248 GIC 122 : return ret;
249 : }
250 :
251 : /*
252 : * Read up to len bytes of data into ptr from a GSSAPI-encrypted connection.
253 : *
254 : * The connection must be already set up for GSSAPI encryption (i.e., GSSAPI
255 : * transport negotiation is complete).
256 : *
257 : * Returns the number of data bytes read, or on failure, returns -1
258 : * with errno set appropriately. If the errno indicates a non-retryable
259 : * error, a message is added to conn->errorMessage. For retryable errors,
260 : * caller should call again once the socket is ready.
261 ECB : */
262 : ssize_t
263 GIC 250 : pg_GSS_read(PGconn *conn, void *ptr, size_t len)
264 : {
265 ECB : OM_uint32 major,
266 : minor;
267 GIC 250 : gss_buffer_desc input = GSS_C_EMPTY_BUFFER,
268 CBC 250 : output = GSS_C_EMPTY_BUFFER;
269 ECB : ssize_t ret;
270 GIC 250 : size_t bytes_returned = 0;
271 250 : gss_ctx_id_t gctx = conn->gctx;
272 :
273 : /*
274 : * The plan here is to read one incoming encrypted packet into
275 : * PqGSSRecvBuffer, decrypt it into PqGSSResultBuffer, and then dole out
276 : * data from there to the caller. When we exhaust the current input
277 ECB : * packet, read another.
278 : */
279 CBC 481 : while (bytes_returned < len)
280 : {
281 GIC 481 : int conf_state = 0;
282 ECB :
283 : /* Check if we have data in our buffer that we can return immediately */
284 CBC 481 : if (PqGSSResultNext < PqGSSResultLength)
285 ECB : {
286 GIC 231 : size_t bytes_in_buffer = PqGSSResultLength - PqGSSResultNext;
287 231 : size_t bytes_to_copy = Min(bytes_in_buffer, len - bytes_returned);
288 :
289 : /*
290 : * Copy the data from our result buffer into the caller's buffer,
291 ECB : * at the point where we last left off filling their buffer.
292 : */
293 CBC 231 : memcpy((char *) ptr + bytes_returned, PqGSSResultBuffer + PqGSSResultNext, bytes_to_copy);
294 GIC 231 : PqGSSResultNext += bytes_to_copy;
295 231 : bytes_returned += bytes_to_copy;
296 :
297 : /*
298 : * At this point, we've either filled the caller's buffer or
299 : * emptied our result buffer. Either way, return to caller. In
300 : * the second case, we could try to read another encrypted packet,
301 : * but the odds are good that there isn't one available. (If this
302 : * isn't true, we chose too small a max packet size.) In any
303 : * case, there's no harm letting the caller process the data we've
304 ECB : * already returned.
305 : */
306 GIC 231 : break;
307 : }
308 ECB :
309 : /* Result buffer is empty, so reset buffer pointers */
310 GIC 250 : PqGSSResultLength = PqGSSResultNext = 0;
311 :
312 : /*
313 : * Because we chose above to return immediately as soon as we emit
314 : * some data, bytes_returned must be zero at this point. Therefore
315 : * the failure exits below can just return -1 without worrying about
316 ECB : * whether we already emitted some data.
317 : */
318 GIC 250 : Assert(bytes_returned == 0);
319 :
320 : /*
321 : * At this point, our result buffer is empty with more bytes being
322 : * requested to be read. We are now ready to load the next packet and
323 : * decrypt it (entirely) into our result buffer.
324 : */
325 ECB :
326 : /* Collect the length if we haven't already */
327 CBC 250 : if (PqGSSRecvLength < sizeof(uint32))
328 ECB : {
329 GIC 250 : ret = pqsecure_raw_read(conn, PqGSSRecvBuffer + PqGSSRecvLength,
330 250 : sizeof(uint32) - PqGSSRecvLength);
331 ECB :
332 : /* If ret <= 0, pqsecure_raw_read already set the correct errno */
333 GIC 250 : if (ret <= 0)
334 CBC 19 : return ret;
335 :
336 GIC 231 : PqGSSRecvLength += ret;
337 ECB :
338 : /* If we still haven't got the length, return to the caller */
339 GBC 231 : if (PqGSSRecvLength < sizeof(uint32))
340 EUB : {
341 UIC 0 : errno = EWOULDBLOCK;
342 0 : return -1;
343 : }
344 : }
345 ECB :
346 : /* Decode the packet length and check for overlength packet */
347 CBC 231 : input.length = pg_ntoh32(*(uint32 *) PqGSSRecvBuffer);
348 :
349 GBC 231 : if (input.length > PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32))
350 EUB : {
351 UNC 0 : libpq_append_conn_error(conn, "oversize GSSAPI packet sent by the server (%zu > %zu)",
352 UBC 0 : (size_t) input.length,
353 : PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32));
354 UIC 0 : errno = EIO; /* for lack of a better idea */
355 0 : return -1;
356 : }
357 :
358 : /*
359 ECB : * Read as much of the packet as we are able to on this call into
360 : * wherever we left off from the last time we were called.
361 : */
362 CBC 231 : ret = pqsecure_raw_read(conn, PqGSSRecvBuffer + PqGSSRecvLength,
363 GBC 231 : input.length - (PqGSSRecvLength - sizeof(uint32)));
364 : /* If ret <= 0, pqsecure_raw_read already set the correct errno */
365 CBC 231 : if (ret <= 0)
366 UIC 0 : return ret;
367 :
368 CBC 231 : PqGSSRecvLength += ret;
369 :
370 EUB : /* If we don't yet have the whole packet, return to the caller */
371 GBC 231 : if (PqGSSRecvLength - sizeof(uint32) < input.length)
372 : {
373 UIC 0 : errno = EWOULDBLOCK;
374 0 : return -1;
375 : }
376 :
377 : /*
378 : * We now have the full packet and we can perform the decryption and
379 : * refill our result buffer, then loop back up to pass data back to
380 ECB : * the caller. Note that error exits below here must take care of
381 : * releasing the gss output buffer.
382 : */
383 GIC 231 : output.value = NULL;
384 CBC 231 : output.length = 0;
385 231 : input.value = PqGSSRecvBuffer + sizeof(uint32);
386 :
387 GBC 231 : major = gss_unwrap(&minor, gctx, &input, &output, &conf_state, NULL);
388 GIC 231 : if (major != GSS_S_COMPLETE)
389 EUB : {
390 UBC 0 : pg_GSS_error(libpq_gettext("GSSAPI unwrap error"), conn,
391 EUB : major, minor);
392 UIC 0 : ret = -1;
393 0 : errno = EIO; /* for lack of a better idea */
394 LBC 0 : goto cleanup;
395 : }
396 EUB :
397 GBC 231 : if (conf_state == 0)
398 EUB : {
399 UNC 0 : libpq_append_conn_error(conn, "incoming GSSAPI message did not use confidentiality");
400 UIC 0 : ret = -1;
401 LBC 0 : errno = EIO; /* for lack of a better idea */
402 0 : goto cleanup;
403 : }
404 :
405 CBC 231 : memcpy(PqGSSResultBuffer, output.value, output.length);
406 GIC 231 : PqGSSResultLength = output.length;
407 :
408 ECB : /* Our receive buffer is now empty, reset it */
409 GIC 231 : PqGSSRecvLength = 0;
410 :
411 ECB : /* Release buffer storage allocated by GSSAPI */
412 GIC 231 : gss_release_buffer(&minor, &output);
413 ECB : }
414 :
415 CBC 231 : ret = bytes_returned;
416 EUB :
417 CBC 231 : cleanup:
418 : /* Release GSSAPI buffer storage, if we didn't already */
419 GIC 231 : if (output.value != NULL)
420 UIC 0 : gss_release_buffer(&minor, &output);
421 GIC 231 : return ret;
422 : }
423 :
424 : /*
425 : * Simple wrapper for reading from pqsecure_raw_read.
426 : *
427 : * This takes the same arguments as pqsecure_raw_read, plus an output parameter
428 ECB : * to return the number of bytes read. This handles if blocking would occur and
429 : * if we detect EOF on the connection.
430 : */
431 : static PostgresPollingStatusType
432 GIC 51 : gss_read(PGconn *conn, void *recv_buffer, size_t length, ssize_t *ret)
433 ECB : {
434 CBC 51 : *ret = pqsecure_raw_read(conn, recv_buffer, length);
435 GIC 51 : if (*ret < 0)
436 EUB : {
437 GIC 15 : if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
438 15 : return PGRES_POLLING_READING;
439 : else
440 LBC 0 : return PGRES_POLLING_FAILED;
441 : }
442 EUB :
443 : /* Check for EOF */
444 GBC 36 : if (*ret == 0)
445 EUB : {
446 UIC 0 : int result = pqReadReady(conn);
447 EUB :
448 UBC 0 : if (result < 0)
449 UIC 0 : return PGRES_POLLING_FAILED;
450 EUB :
451 UBC 0 : if (!result)
452 UIC 0 : return PGRES_POLLING_READING;
453 EUB :
454 UBC 0 : *ret = pqsecure_raw_read(conn, recv_buffer, length);
455 UIC 0 : if (*ret < 0)
456 EUB : {
457 UIC 0 : if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
458 UBC 0 : return PGRES_POLLING_READING;
459 EUB : else
460 UIC 0 : return PGRES_POLLING_FAILED;
461 : }
462 LBC 0 : if (*ret == 0)
463 UIC 0 : return PGRES_POLLING_FAILED;
464 : }
465 :
466 GIC 36 : return PGRES_POLLING_OK;
467 : }
468 :
469 : /*
470 : * Negotiate GSSAPI transport for a connection. When complete, returns
471 : * PGRES_POLLING_OK. Will return PGRES_POLLING_READING or
472 ECB : * PGRES_POLLING_WRITING as appropriate whenever it would block, and
473 : * PGRES_POLLING_FAILED if transport could not be negotiated.
474 : */
475 : PostgresPollingStatusType
476 GIC 51 : pqsecure_open_gss(PGconn *conn)
477 : {
478 : ssize_t ret;
479 ECB : OM_uint32 major,
480 : minor;
481 : uint32 netlen;
482 : PostgresPollingStatusType result;
483 GIC 51 : gss_buffer_desc input = GSS_C_EMPTY_BUFFER,
484 51 : output = GSS_C_EMPTY_BUFFER;
485 :
486 : /*
487 : * If first time through for this connection, allocate buffers and
488 ECB : * initialize state variables. By malloc'ing the buffers separately, we
489 : * ensure that they are sufficiently aligned for the length-word accesses
490 : * that we do in some places in this file.
491 : */
492 CBC 51 : if (PqGSSSendBuffer == NULL)
493 ECB : {
494 GIC 18 : PqGSSSendBuffer = malloc(PQ_GSS_SEND_BUFFER_SIZE);
495 GBC 18 : PqGSSRecvBuffer = malloc(PQ_GSS_RECV_BUFFER_SIZE);
496 18 : PqGSSResultBuffer = malloc(PQ_GSS_RECV_BUFFER_SIZE);
497 GIC 18 : if (!PqGSSSendBuffer || !PqGSSRecvBuffer || !PqGSSResultBuffer)
498 ECB : {
499 UNC 0 : libpq_append_conn_error(conn, "out of memory");
500 UIC 0 : return PGRES_POLLING_FAILED;
501 : }
502 GIC 18 : PqGSSSendLength = PqGSSSendNext = PqGSSSendConsumed = 0;
503 18 : PqGSSRecvLength = PqGSSResultLength = PqGSSResultNext = 0;
504 ECB : }
505 :
506 : /*
507 : * Check if we have anything to send from a prior call and if so, send it.
508 : */
509 CBC 51 : if (PqGSSSendLength)
510 : {
511 GBC 18 : ssize_t amount = PqGSSSendLength - PqGSSSendNext;
512 EUB :
513 GIC 18 : ret = pqsecure_raw_write(conn, PqGSSSendBuffer + PqGSSSendNext, amount);
514 GBC 18 : if (ret < 0)
515 : {
516 UIC 0 : if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
517 LBC 0 : return PGRES_POLLING_WRITING;
518 : else
519 UBC 0 : return PGRES_POLLING_FAILED;
520 EUB : }
521 :
522 GIC 18 : if (ret < amount)
523 ECB : {
524 UIC 0 : PqGSSSendNext += ret;
525 0 : return PGRES_POLLING_WRITING;
526 : }
527 :
528 GIC 18 : PqGSSSendLength = PqGSSSendNext = 0;
529 : }
530 :
531 ECB : /*
532 : * Client sends first, and sending creates a context, therefore this will
533 : * be false the first time through, and then when we get called again we
534 : * will check for incoming data.
535 : */
536 CBC 51 : if (conn->gctx)
537 : {
538 : /* Process any incoming data we might have */
539 ECB :
540 : /* See if we are still trying to get the length */
541 CBC 33 : if (PqGSSRecvLength < sizeof(uint32))
542 : {
543 ECB : /* Attempt to get the length first */
544 GIC 33 : result = gss_read(conn, PqGSSRecvBuffer + PqGSSRecvLength, sizeof(uint32) - PqGSSRecvLength, &ret);
545 CBC 33 : if (result != PGRES_POLLING_OK)
546 GBC 15 : return result;
547 :
548 GIC 18 : PqGSSRecvLength += ret;
549 :
550 18 : if (PqGSSRecvLength < sizeof(uint32))
551 UIC 0 : return PGRES_POLLING_READING;
552 : }
553 :
554 : /*
555 : * Check if we got an error packet
556 : *
557 ECB : * This is safe to do because we shouldn't ever get a packet over 8192
558 : * and therefore the actual length bytes, being that they are in
559 : * network byte order, for any real packet will start with two zero
560 : * bytes.
561 : */
562 GIC 18 : if (PqGSSRecvBuffer[0] == 'E')
563 : {
564 : /*
565 EUB : * For an error packet during startup, we don't get a length, so
566 : * simply read as much as we can fit into our buffer (as a string,
567 : * so leave a spot at the end for a NULL byte too) and report that
568 : * back to the caller.
569 : */
570 UIC 0 : result = gss_read(conn, PqGSSRecvBuffer + PqGSSRecvLength, PQ_GSS_RECV_BUFFER_SIZE - PqGSSRecvLength - 1, &ret);
571 UBC 0 : if (result != PGRES_POLLING_OK)
572 0 : return result;
573 EUB :
574 UIC 0 : PqGSSRecvLength += ret;
575 EUB :
576 UIC 0 : Assert(PqGSSRecvLength < PQ_GSS_RECV_BUFFER_SIZE);
577 0 : PqGSSRecvBuffer[PqGSSRecvLength] = '\0';
578 0 : appendPQExpBuffer(&conn->errorMessage, "%s\n", PqGSSRecvBuffer + 1);
579 :
580 0 : return PGRES_POLLING_FAILED;
581 : }
582 :
583 : /*
584 ECB : * We should have the whole length at this point, so pull it out and
585 : * then read whatever we have left of the packet
586 : */
587 EUB :
588 : /* Get the length and check for over-length packet */
589 GIC 18 : input.length = pg_ntoh32(*(uint32 *) PqGSSRecvBuffer);
590 GBC 18 : if (input.length > PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32))
591 : {
592 UNC 0 : libpq_append_conn_error(conn, "oversize GSSAPI packet sent by the server (%zu > %zu)",
593 UIC 0 : (size_t) input.length,
594 : PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32));
595 0 : return PGRES_POLLING_FAILED;
596 ECB : }
597 :
598 : /*
599 EUB : * Read as much of the packet as we are able to on this call into
600 : * wherever we left off from the last time we were called.
601 ECB : */
602 GIC 18 : result = gss_read(conn, PqGSSRecvBuffer + PqGSSRecvLength,
603 18 : input.length - (PqGSSRecvLength - sizeof(uint32)), &ret);
604 18 : if (result != PGRES_POLLING_OK)
605 UIC 0 : return result;
606 :
607 CBC 18 : PqGSSRecvLength += ret;
608 EUB :
609 : /*
610 ECB : * If we got less than the rest of the packet then we need to return
611 : * and be called again.
612 : */
613 GIC 18 : if (PqGSSRecvLength - sizeof(uint32) < input.length)
614 LBC 0 : return PGRES_POLLING_READING;
615 ECB :
616 GBC 18 : input.value = PqGSSRecvBuffer + sizeof(uint32);
617 : }
618 :
619 : /* Load the service name (no-op if already done */
620 GIC 36 : ret = pg_GSS_load_servicename(conn);
621 36 : if (ret != STATUS_OK)
622 LBC 0 : return PGRES_POLLING_FAILED;
623 :
624 : /*
625 : * Call GSS init context, either with an empty input, or with a complete
626 : * packet from the server.
627 : */
628 CBC 36 : major = gss_init_sec_context(&minor, conn->gcred, &conn->gctx,
629 : conn->gtarg_nam, GSS_C_NO_OID,
630 ECB : GSS_REQUIRED_FLAGS, 0, 0, &input, NULL,
631 : &output, NULL, NULL);
632 EUB :
633 : /* GSS Init Sec Context uses the whole packet, so clear it */
634 GBC 36 : PqGSSRecvLength = 0;
635 :
636 GIC 36 : if (GSS_ERROR(major))
637 ECB : {
638 UIC 0 : pg_GSS_error(libpq_gettext("could not initiate GSSAPI security context"),
639 : conn, major, minor);
640 0 : return PGRES_POLLING_FAILED;
641 : }
642 :
643 CBC 36 : if (output.length == 0)
644 : {
645 : /*
646 ECB : * We're done - hooray! Set flag to tell the low-level I/O routines
647 : * to do GSS wrapping/unwrapping.
648 : */
649 GIC 18 : conn->gssenc = true;
650 :
651 : /* Clean up */
652 18 : gss_release_cred(&minor, &conn->gcred);
653 18 : conn->gcred = GSS_C_NO_CREDENTIAL;
654 CBC 18 : gss_release_buffer(&minor, &output);
655 :
656 ECB : /*
657 : * Determine the max packet size which will fit in our buffer, after
658 : * accounting for the length. pg_GSS_write will need this.
659 : */
660 GBC 18 : major = gss_wrap_size_limit(&minor, conn->gctx, 1, GSS_C_QOP_DEFAULT,
661 : PQ_GSS_SEND_BUFFER_SIZE - sizeof(uint32),
662 18 : &PqGSSMaxPktSize);
663 :
664 GIC 18 : if (GSS_ERROR(major))
665 ECB : {
666 UIC 0 : pg_GSS_error(libpq_gettext("GSSAPI size check error"), conn,
667 : major, minor);
668 0 : return PGRES_POLLING_FAILED;
669 ECB : }
670 :
671 GBC 18 : return PGRES_POLLING_OK;
672 : }
673 EUB :
674 : /* Must have output.length > 0 */
675 GIC 18 : if (output.length > PQ_GSS_SEND_BUFFER_SIZE - sizeof(uint32))
676 : {
677 UIC 0 : pg_GSS_error(libpq_gettext("GSSAPI context establishment error"),
678 ECB : conn, major, minor);
679 UIC 0 : gss_release_buffer(&minor, &output);
680 LBC 0 : return PGRES_POLLING_FAILED;
681 ECB : }
682 :
683 : /* Queue the token for writing */
684 CBC 18 : netlen = pg_hton32(output.length);
685 :
686 GIC 18 : memcpy(PqGSSSendBuffer, (char *) &netlen, sizeof(uint32));
687 18 : PqGSSSendLength += sizeof(uint32);
688 :
689 CBC 18 : memcpy(PqGSSSendBuffer + PqGSSSendLength, output.value, output.length);
690 GIC 18 : PqGSSSendLength += output.length;
691 :
692 ECB : /* We don't bother with PqGSSSendConsumed here */
693 :
694 : /* Release buffer storage allocated by GSSAPI */
695 GIC 18 : gss_release_buffer(&minor, &output);
696 :
697 : /* Ask to be called again to write data */
698 18 : return PGRES_POLLING_WRITING;
699 : }
700 :
701 : /*
702 : * GSSAPI Information functions.
703 EUB : */
704 :
705 : /*
706 : * Return the GSSAPI Context itself.
707 : */
708 : void *
709 UIC 0 : PQgetgssctx(PGconn *conn)
710 : {
711 0 : if (!conn)
712 0 : return NULL;
713 :
714 0 : return conn->gctx;
715 ECB : }
716 :
717 : /*
718 : * Return true if GSSAPI encryption is in use.
719 : */
720 EUB : int
721 GIC 2 : PQgssEncInUse(PGconn *conn)
722 : {
723 2 : if (!conn || !conn->gctx)
724 2 : return 0;
725 :
726 UIC 0 : return conn->gssenc;
727 : }
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