1 /* GSSAPI/krb5 support for FTP - loosely based on old krb4.c
2 *
3 * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska Högskolan
4 * (Royal Institute of Technology, Stockholm, Sweden).
5 * Copyright (C) Daniel Stenberg
6 * All rights reserved.
7 *
8 * SPDX-License-Identifier: BSD-3-Clause
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 *
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 *
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 *
21 * 3. Neither the name of the Institute nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE. */
36
37 #include "curl_setup.h"
38
39 #if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_FTP)
40
41 #ifdef HAVE_NETDB_H
42 #include <netdb.h>
43 #endif
44 #ifdef HAVE_ARPA_INET_H
45 #include <arpa/inet.h>
46 #endif
47
48 #include "urldata.h"
49 #include "cfilters.h"
50 #include "cf-socket.h"
51 #include "curl_base64.h"
52 #include "ftp.h"
53 #include "curl_gssapi.h"
54 #include "sendf.h"
55 #include "transfer.h"
56 #include "curl_krb5.h"
57 #include "warnless.h"
58 #include "strcase.h"
59 #include "strdup.h"
60
61 /* The last 3 #include files should be in this order */
62 #include "curl_printf.h"
63 #include "curl_memory.h"
64 #include "memdebug.h"
65
ftpsend(struct Curl_easy * data,struct connectdata * conn,const char * cmd)66 static CURLcode ftpsend(struct Curl_easy *data, struct connectdata *conn,
67 const char *cmd)
68 {
69 size_t bytes_written;
70 #define SBUF_SIZE 1024
71 char s[SBUF_SIZE];
72 size_t write_len;
73 char *sptr = s;
74 CURLcode result = CURLE_OK;
75 #ifdef HAVE_GSSAPI
76 unsigned char data_sec = conn->data_prot;
77 #endif
78
79 DEBUGASSERT(cmd);
80
81 write_len = strlen(cmd);
82 if(!write_len || write_len > (sizeof(s) -3))
83 return CURLE_BAD_FUNCTION_ARGUMENT;
84
85 memcpy(&s, cmd, write_len);
86 strcpy(&s[write_len], "\r\n"); /* append a trailing CRLF */
87 write_len += 2;
88 bytes_written = 0;
89
90 for(;;) {
91 #ifdef HAVE_GSSAPI
92 conn->data_prot = PROT_CMD;
93 #endif
94 result = Curl_xfer_send(data, sptr, write_len, FALSE, &bytes_written);
95 #ifdef HAVE_GSSAPI
96 DEBUGASSERT(data_sec > PROT_NONE && data_sec < PROT_LAST);
97 conn->data_prot = data_sec;
98 #endif
99
100 if(result)
101 break;
102
103 Curl_debug(data, CURLINFO_HEADER_OUT, sptr, bytes_written);
104
105 if(bytes_written != write_len) {
106 write_len -= bytes_written;
107 sptr += bytes_written;
108 }
109 else
110 break;
111 }
112
113 return result;
114 }
115
116 static int
krb5_init(void * app_data)117 krb5_init(void *app_data)
118 {
119 gss_ctx_id_t *context = app_data;
120 /* Make sure our context is initialized for krb5_end. */
121 *context = GSS_C_NO_CONTEXT;
122 return 0;
123 }
124
125 static int
krb5_check_prot(void * app_data,int level)126 krb5_check_prot(void *app_data, int level)
127 {
128 (void)app_data; /* unused */
129 if(level == PROT_CONFIDENTIAL)
130 return -1;
131 return 0;
132 }
133
134 static int
krb5_decode(void * app_data,void * buf,int len,int level UNUSED_PARAM,struct connectdata * conn UNUSED_PARAM)135 krb5_decode(void *app_data, void *buf, int len,
136 int level UNUSED_PARAM,
137 struct connectdata *conn UNUSED_PARAM)
138 {
139 gss_ctx_id_t *context = app_data;
140 OM_uint32 maj, min;
141 gss_buffer_desc enc, dec;
142
143 (void)level;
144 (void)conn;
145
146 enc.value = buf;
147 enc.length = len;
148 maj = gss_unwrap(&min, *context, &enc, &dec, NULL, NULL);
149 if(maj != GSS_S_COMPLETE)
150 return -1;
151
152 memcpy(buf, dec.value, dec.length);
153 len = curlx_uztosi(dec.length);
154 gss_release_buffer(&min, &dec);
155
156 return len;
157 }
158
159 static int
krb5_encode(void * app_data,const void * from,int length,int level,void ** to)160 krb5_encode(void *app_data, const void *from, int length, int level, void **to)
161 {
162 gss_ctx_id_t *context = app_data;
163 gss_buffer_desc dec, enc;
164 OM_uint32 maj, min;
165 int state;
166 int len;
167
168 /* NOTE that the cast is safe, neither of the krb5, gnu gss and heimdal
169 * libraries modify the input buffer in gss_wrap()
170 */
171 dec.value = (void *)from;
172 dec.length = (size_t)length;
173 maj = gss_wrap(&min, *context,
174 level == PROT_PRIVATE,
175 GSS_C_QOP_DEFAULT,
176 &dec, &state, &enc);
177
178 if(maj != GSS_S_COMPLETE)
179 return -1;
180
181 /* malloc a new buffer, in case gss_release_buffer does not work as
182 expected */
183 *to = malloc(enc.length);
184 if(!*to)
185 return -1;
186 memcpy(*to, enc.value, enc.length);
187 len = curlx_uztosi(enc.length);
188 gss_release_buffer(&min, &enc);
189 return len;
190 }
191
192 static int
krb5_auth(void * app_data,struct Curl_easy * data,struct connectdata * conn)193 krb5_auth(void *app_data, struct Curl_easy *data, struct connectdata *conn)
194 {
195 int ret = AUTH_OK;
196 char *p;
197 const char *host = conn->host.name;
198 ssize_t nread;
199 curl_socklen_t l = sizeof(conn->local_addr);
200 CURLcode result;
201 const char *service = data->set.str[STRING_SERVICE_NAME] ?
202 data->set.str[STRING_SERVICE_NAME] :
203 "ftp";
204 const char *srv_host = "host";
205 gss_buffer_desc input_buffer, output_buffer, *gssresp;
206 gss_buffer_desc _gssresp = GSS_C_EMPTY_BUFFER;
207 OM_uint32 maj, min;
208 gss_name_t gssname;
209 gss_ctx_id_t *context = app_data;
210 struct gss_channel_bindings_struct chan;
211 size_t base64_sz = 0;
212 struct sockaddr_in *remote_addr =
213 (struct sockaddr_in *)(void *)&conn->remote_addr->curl_sa_addr;
214 char *stringp;
215
216 if(getsockname(conn->sock[FIRSTSOCKET],
217 (struct sockaddr *)&conn->local_addr, &l) < 0)
218 perror("getsockname()");
219
220 chan.initiator_addrtype = GSS_C_AF_INET;
221 chan.initiator_address.length = l - 4;
222 chan.initiator_address.value = &conn->local_addr.sin_addr.s_addr;
223 chan.acceptor_addrtype = GSS_C_AF_INET;
224 chan.acceptor_address.length = l - 4;
225 chan.acceptor_address.value = &remote_addr->sin_addr.s_addr;
226 chan.application_data.length = 0;
227 chan.application_data.value = NULL;
228
229 /* this loop will execute twice (once for service, once for host) */
230 for(;;) {
231 /* this really should not be repeated here, but cannot help it */
232 if(service == srv_host) {
233 result = ftpsend(data, conn, "AUTH GSSAPI");
234 if(result)
235 return -2;
236
237 if(Curl_GetFTPResponse(data, &nread, NULL))
238 return -1;
239 else {
240 struct pingpong *pp = &conn->proto.ftpc.pp;
241 char *line = Curl_dyn_ptr(&pp->recvbuf);
242 if(line[0] != '3')
243 return -1;
244 }
245 }
246
247 stringp = aprintf("%s@%s", service, host);
248 if(!stringp)
249 return -2;
250
251 input_buffer.value = stringp;
252 input_buffer.length = strlen(stringp);
253 maj = gss_import_name(&min, &input_buffer, GSS_C_NT_HOSTBASED_SERVICE,
254 &gssname);
255 free(stringp);
256 if(maj != GSS_S_COMPLETE) {
257 gss_release_name(&min, &gssname);
258 if(service == srv_host) {
259 failf(data, "Error importing service name %s@%s", service, host);
260 return AUTH_ERROR;
261 }
262 service = srv_host;
263 continue;
264 }
265 /* We pass NULL as |output_name_type| to avoid a leak. */
266 gss_display_name(&min, gssname, &output_buffer, NULL);
267 infof(data, "Trying against %s", (char *)output_buffer.value);
268 gssresp = GSS_C_NO_BUFFER;
269 *context = GSS_C_NO_CONTEXT;
270
271 do {
272 /* Release the buffer at each iteration to avoid leaking: the first time
273 we are releasing the memory from gss_display_name. The last item is
274 taken care by a final gss_release_buffer. */
275 gss_release_buffer(&min, &output_buffer);
276 ret = AUTH_OK;
277 maj = Curl_gss_init_sec_context(data,
278 &min,
279 context,
280 gssname,
281 &Curl_krb5_mech_oid,
282 &chan,
283 gssresp,
284 &output_buffer,
285 TRUE,
286 NULL);
287
288 if(gssresp) {
289 free(_gssresp.value);
290 gssresp = NULL;
291 }
292
293 if(GSS_ERROR(maj)) {
294 infof(data, "Error creating security context");
295 ret = AUTH_ERROR;
296 break;
297 }
298
299 if(output_buffer.length) {
300 char *cmd;
301
302 result = Curl_base64_encode((char *)output_buffer.value,
303 output_buffer.length, &p, &base64_sz);
304 if(result) {
305 infof(data, "base64-encoding: %s", curl_easy_strerror(result));
306 ret = AUTH_ERROR;
307 break;
308 }
309
310 cmd = aprintf("ADAT %s", p);
311 if(cmd)
312 result = ftpsend(data, conn, cmd);
313 else
314 result = CURLE_OUT_OF_MEMORY;
315
316 free(p);
317 free(cmd);
318
319 if(result) {
320 ret = -2;
321 break;
322 }
323
324 if(Curl_GetFTPResponse(data, &nread, NULL)) {
325 ret = -1;
326 break;
327 }
328 else {
329 struct pingpong *pp = &conn->proto.ftpc.pp;
330 size_t len = Curl_dyn_len(&pp->recvbuf);
331 p = Curl_dyn_ptr(&pp->recvbuf);
332 if((len < 4) || (p[0] != '2' && p[0] != '3')) {
333 infof(data, "Server did not accept auth data");
334 ret = AUTH_ERROR;
335 break;
336 }
337 }
338
339 _gssresp.value = NULL; /* make sure it is initialized */
340 _gssresp.length = 0;
341 p += 4; /* over '789 ' */
342 p = strstr(p, "ADAT=");
343 if(p) {
344 unsigned char *outptr;
345 size_t outlen;
346 result = Curl_base64_decode(p + 5, &outptr, &outlen);
347 if(result) {
348 failf(data, "base64-decoding: %s", curl_easy_strerror(result));
349 ret = AUTH_CONTINUE;
350 break;
351 }
352 _gssresp.value = outptr;
353 _gssresp.length = outlen;
354 }
355
356 gssresp = &_gssresp;
357 }
358 } while(maj == GSS_S_CONTINUE_NEEDED);
359
360 gss_release_name(&min, &gssname);
361 gss_release_buffer(&min, &output_buffer);
362
363 if(gssresp)
364 free(_gssresp.value);
365
366 if(ret == AUTH_OK || service == srv_host)
367 break;
368
369 service = srv_host;
370 }
371 return ret;
372 }
373
krb5_end(void * app_data)374 static void krb5_end(void *app_data)
375 {
376 OM_uint32 min;
377 gss_ctx_id_t *context = app_data;
378 if(*context != GSS_C_NO_CONTEXT) {
379 OM_uint32 maj = gss_delete_sec_context(&min, context, GSS_C_NO_BUFFER);
380 (void)maj;
381 DEBUGASSERT(maj == GSS_S_COMPLETE);
382 }
383 }
384
385 static const struct Curl_sec_client_mech Curl_krb5_client_mech = {
386 "GSSAPI",
387 sizeof(gss_ctx_id_t),
388 krb5_init,
389 krb5_auth,
390 krb5_end,
391 krb5_check_prot,
392
393 krb5_encode,
394 krb5_decode
395 };
396
397 static const struct {
398 unsigned char level;
399 const char *name;
400 } level_names[] = {
401 { PROT_CLEAR, "clear" },
402 { PROT_SAFE, "safe" },
403 { PROT_CONFIDENTIAL, "confidential" },
404 { PROT_PRIVATE, "private" }
405 };
406
name_to_level(const char * name)407 static unsigned char name_to_level(const char *name)
408 {
409 int i;
410 for(i = 0; i < (int)sizeof(level_names)/(int)sizeof(level_names[0]); i++)
411 if(curl_strequal(name, level_names[i].name))
412 return level_names[i].level;
413 return PROT_NONE;
414 }
415
416 /* Convert a protocol |level| to its char representation.
417 We take an int to catch programming mistakes. */
level_to_char(int level)418 static char level_to_char(int level)
419 {
420 switch(level) {
421 case PROT_CLEAR:
422 return 'C';
423 case PROT_SAFE:
424 return 'S';
425 case PROT_CONFIDENTIAL:
426 return 'E';
427 case PROT_PRIVATE:
428 return 'P';
429 case PROT_CMD:
430 default:
431 /* Those 2 cases should not be reached! */
432 break;
433 }
434 DEBUGASSERT(0);
435 /* Default to the most secure alternative. */
436 return 'P';
437 }
438
439 /* Send an FTP command defined by |message| and the optional arguments. The
440 function returns the ftp_code. If an error occurs, -1 is returned. */
441 static int ftp_send_command(struct Curl_easy *data, const char *message, ...)
442 CURL_PRINTF(2, 3);
443
ftp_send_command(struct Curl_easy * data,const char * message,...)444 static int ftp_send_command(struct Curl_easy *data, const char *message, ...)
445 {
446 int ftp_code;
447 ssize_t nread = 0;
448 va_list args;
449 char print_buffer[50];
450
451 va_start(args, message);
452 mvsnprintf(print_buffer, sizeof(print_buffer), message, args);
453 va_end(args);
454
455 if(ftpsend(data, data->conn, print_buffer)) {
456 ftp_code = -1;
457 }
458 else {
459 if(Curl_GetFTPResponse(data, &nread, &ftp_code))
460 ftp_code = -1;
461 }
462
463 (void)nread; /* Unused */
464 return ftp_code;
465 }
466
467 /* Read |len| from the socket |fd| and store it in |to|. Return a CURLcode
468 saying whether an error occurred or CURLE_OK if |len| was read. */
469 static CURLcode
socket_read(struct Curl_easy * data,int sockindex,void * to,size_t len)470 socket_read(struct Curl_easy *data, int sockindex, void *to, size_t len)
471 {
472 char *to_p = to;
473 CURLcode result;
474 ssize_t nread = 0;
475
476 while(len > 0) {
477 result = Curl_conn_recv(data, sockindex, to_p, len, &nread);
478 if(nread > 0) {
479 len -= nread;
480 to_p += nread;
481 }
482 else {
483 if(result == CURLE_AGAIN)
484 continue;
485 return result;
486 }
487 }
488 return CURLE_OK;
489 }
490
491
492 /* Write |len| bytes from the buffer |to| to the socket |fd|. Return a
493 CURLcode saying whether an error occurred or CURLE_OK if |len| was
494 written. */
495 static CURLcode
socket_write(struct Curl_easy * data,int sockindex,const void * to,size_t len)496 socket_write(struct Curl_easy *data, int sockindex, const void *to,
497 size_t len)
498 {
499 const char *to_p = to;
500 CURLcode result;
501 size_t written;
502
503 while(len > 0) {
504 result = Curl_conn_send(data, sockindex, to_p, len, FALSE, &written);
505 if(!result && written > 0) {
506 len -= written;
507 to_p += written;
508 }
509 else {
510 if(result == CURLE_AGAIN)
511 continue;
512 return result;
513 }
514 }
515 return CURLE_OK;
516 }
517
read_data(struct Curl_easy * data,int sockindex,struct krb5buffer * buf)518 static CURLcode read_data(struct Curl_easy *data, int sockindex,
519 struct krb5buffer *buf)
520 {
521 struct connectdata *conn = data->conn;
522 int len;
523 CURLcode result;
524 int nread;
525
526 result = socket_read(data, sockindex, &len, sizeof(len));
527 if(result)
528 return result;
529
530 if(len) {
531 len = (int)ntohl((uint32_t)len);
532 if(len > CURL_MAX_INPUT_LENGTH)
533 return CURLE_TOO_LARGE;
534
535 Curl_dyn_reset(&buf->buf);
536 }
537 else
538 return CURLE_RECV_ERROR;
539
540 do {
541 char buffer[1024];
542 nread = CURLMIN(len, (int)sizeof(buffer));
543 result = socket_read(data, sockindex, buffer, (size_t)nread);
544 if(result)
545 return result;
546 result = Curl_dyn_addn(&buf->buf, buffer, nread);
547 if(result)
548 return result;
549 len -= nread;
550 } while(len);
551 /* this decodes the dynbuf *in place* */
552 nread = conn->mech->decode(conn->app_data,
553 Curl_dyn_ptr(&buf->buf),
554 len, conn->data_prot, conn);
555 if(nread < 0)
556 return CURLE_RECV_ERROR;
557 Curl_dyn_setlen(&buf->buf, nread);
558 buf->index = 0;
559 return CURLE_OK;
560 }
561
562 static size_t
buffer_read(struct krb5buffer * buf,void * data,size_t len)563 buffer_read(struct krb5buffer *buf, void *data, size_t len)
564 {
565 size_t size = Curl_dyn_len(&buf->buf);
566 if(size - buf->index < len)
567 len = size - buf->index;
568 memcpy(data, Curl_dyn_ptr(&buf->buf) + buf->index, len);
569 buf->index += len;
570 return len;
571 }
572
573 /* Matches Curl_recv signature */
sec_recv(struct Curl_easy * data,int sockindex,char * buffer,size_t len,CURLcode * err)574 static ssize_t sec_recv(struct Curl_easy *data, int sockindex,
575 char *buffer, size_t len, CURLcode *err)
576 {
577 size_t bytes_read;
578 size_t total_read = 0;
579 struct connectdata *conn = data->conn;
580
581 *err = CURLE_OK;
582
583 /* Handle clear text response. */
584 if(conn->sec_complete == 0 || conn->data_prot == PROT_CLEAR) {
585 ssize_t nread;
586 *err = Curl_conn_recv(data, sockindex, buffer, len, &nread);
587 return nread;
588 }
589
590 if(conn->in_buffer.eof_flag) {
591 conn->in_buffer.eof_flag = 0;
592 return 0;
593 }
594
595 bytes_read = buffer_read(&conn->in_buffer, buffer, len);
596 len -= bytes_read;
597 total_read += bytes_read;
598 buffer += bytes_read;
599
600 while(len > 0) {
601 if(read_data(data, sockindex, &conn->in_buffer))
602 return -1;
603 if(Curl_dyn_len(&conn->in_buffer.buf) == 0) {
604 if(bytes_read > 0)
605 conn->in_buffer.eof_flag = 1;
606 return bytes_read;
607 }
608 bytes_read = buffer_read(&conn->in_buffer, buffer, len);
609 len -= bytes_read;
610 total_read += bytes_read;
611 buffer += bytes_read;
612 }
613 return total_read;
614 }
615
616 /* Send |length| bytes from |from| to the |sockindex| socket taking care of
617 encoding and negotiating with the server. |from| can be NULL. */
do_sec_send(struct Curl_easy * data,struct connectdata * conn,int sockindex,const char * from,int length)618 static void do_sec_send(struct Curl_easy *data, struct connectdata *conn,
619 int sockindex, const char *from, int length)
620 {
621 int bytes, htonl_bytes; /* 32-bit integers for htonl */
622 char *buffer = NULL;
623 char *cmd_buffer;
624 size_t cmd_size = 0;
625 CURLcode error;
626 enum protection_level prot_level = conn->data_prot;
627 bool iscmd = (prot_level == PROT_CMD);
628
629 DEBUGASSERT(prot_level > PROT_NONE && prot_level < PROT_LAST);
630
631 if(iscmd) {
632 if(!strncmp(from, "PASS ", 5) || !strncmp(from, "ACCT ", 5))
633 prot_level = PROT_PRIVATE;
634 else
635 prot_level = conn->command_prot;
636 }
637 bytes = conn->mech->encode(conn->app_data, from, length, (int)prot_level,
638 (void **)&buffer);
639 if(!buffer || bytes <= 0)
640 return; /* error */
641
642 if(iscmd) {
643 error = Curl_base64_encode(buffer, curlx_sitouz(bytes),
644 &cmd_buffer, &cmd_size);
645 if(error) {
646 free(buffer);
647 return; /* error */
648 }
649 if(cmd_size > 0) {
650 static const char *enc = "ENC ";
651 static const char *mic = "MIC ";
652 if(prot_level == PROT_PRIVATE)
653 socket_write(data, sockindex, enc, 4);
654 else
655 socket_write(data, sockindex, mic, 4);
656
657 socket_write(data, sockindex, cmd_buffer, cmd_size);
658 socket_write(data, sockindex, "\r\n", 2);
659 infof(data, "Send: %s%s", prot_level == PROT_PRIVATE ? enc : mic,
660 cmd_buffer);
661 free(cmd_buffer);
662 }
663 }
664 else {
665 htonl_bytes = (int)htonl((OM_uint32)bytes);
666 socket_write(data, sockindex, &htonl_bytes, sizeof(htonl_bytes));
667 socket_write(data, sockindex, buffer, curlx_sitouz(bytes));
668 }
669 free(buffer);
670 }
671
sec_write(struct Curl_easy * data,struct connectdata * conn,int sockindex,const char * buffer,size_t length)672 static ssize_t sec_write(struct Curl_easy *data, struct connectdata *conn,
673 int sockindex, const char *buffer, size_t length)
674 {
675 ssize_t tx = 0, len = conn->buffer_size;
676
677 if(len <= 0)
678 len = length;
679 while(length) {
680 if(length < (size_t)len)
681 len = length;
682
683 do_sec_send(data, conn, sockindex, buffer, curlx_sztosi(len));
684 length -= len;
685 buffer += len;
686 tx += len;
687 }
688 return tx;
689 }
690
691 /* Matches Curl_send signature */
sec_send(struct Curl_easy * data,int sockindex,const void * buffer,size_t len,bool eos,CURLcode * err)692 static ssize_t sec_send(struct Curl_easy *data, int sockindex,
693 const void *buffer, size_t len, bool eos,
694 CURLcode *err)
695 {
696 struct connectdata *conn = data->conn;
697 (void)eos; /* unused */
698 *err = CURLE_OK;
699 return sec_write(data, conn, sockindex, buffer, len);
700 }
701
Curl_sec_read_msg(struct Curl_easy * data,struct connectdata * conn,char * buffer,enum protection_level level)702 int Curl_sec_read_msg(struct Curl_easy *data, struct connectdata *conn,
703 char *buffer, enum protection_level level)
704 {
705 /* decoded_len should be size_t or ssize_t but conn->mech->decode returns an
706 int */
707 int decoded_len;
708 char *buf;
709 int ret_code = 0;
710 size_t decoded_sz = 0;
711 CURLcode error;
712
713 (void) data;
714
715 if(!conn->mech)
716 /* not initialized, return error */
717 return -1;
718
719 DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
720
721 error = Curl_base64_decode(buffer + 4, (unsigned char **)&buf, &decoded_sz);
722 if(error || decoded_sz == 0)
723 return -1;
724
725 if(decoded_sz > (size_t)INT_MAX) {
726 free(buf);
727 return -1;
728 }
729 decoded_len = curlx_uztosi(decoded_sz);
730
731 decoded_len = conn->mech->decode(conn->app_data, buf, decoded_len,
732 (int)level, conn);
733 if(decoded_len <= 0) {
734 free(buf);
735 return -1;
736 }
737
738 {
739 buf[decoded_len] = '\n';
740 Curl_debug(data, CURLINFO_HEADER_IN, buf, decoded_len + 1);
741 }
742
743 buf[decoded_len] = '\0';
744 if(decoded_len <= 3)
745 /* suspiciously short */
746 return 0;
747
748 if(buf[3] != '-')
749 ret_code = atoi(buf);
750
751 if(buf[decoded_len - 1] == '\n')
752 buf[decoded_len - 1] = '\0';
753 strcpy(buffer, buf);
754 free(buf);
755 return ret_code;
756 }
757
sec_set_protection_level(struct Curl_easy * data)758 static int sec_set_protection_level(struct Curl_easy *data)
759 {
760 int code;
761 struct connectdata *conn = data->conn;
762 unsigned char level = conn->request_data_prot;
763
764 DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
765
766 if(!conn->sec_complete) {
767 infof(data, "Trying to change the protection level after the"
768 " completion of the data exchange.");
769 return -1;
770 }
771
772 /* Bail out if we try to set up the same level */
773 if(conn->data_prot == level)
774 return 0;
775
776 if(level) {
777 char *pbsz;
778 unsigned int buffer_size = 1 << 20; /* 1048576 */
779 struct pingpong *pp = &conn->proto.ftpc.pp;
780 char *line;
781
782 code = ftp_send_command(data, "PBSZ %u", buffer_size);
783 if(code < 0)
784 return -1;
785
786 if(code/100 != 2) {
787 failf(data, "Failed to set the protection's buffer size.");
788 return -1;
789 }
790 conn->buffer_size = buffer_size;
791
792 line = Curl_dyn_ptr(&pp->recvbuf);
793 pbsz = strstr(line, "PBSZ=");
794 if(pbsz) {
795 /* stick to default value if the check fails */
796 if(ISDIGIT(pbsz[5]))
797 buffer_size = (unsigned int)atoi(&pbsz[5]);
798 if(buffer_size < conn->buffer_size)
799 conn->buffer_size = buffer_size;
800 }
801 }
802
803 /* Now try to negotiate the protection level. */
804 code = ftp_send_command(data, "PROT %c", level_to_char(level));
805
806 if(code < 0)
807 return -1;
808
809 if(code/100 != 2) {
810 failf(data, "Failed to set the protection level.");
811 return -1;
812 }
813
814 conn->data_prot = level;
815 if(level == PROT_PRIVATE)
816 conn->command_prot = level;
817
818 return 0;
819 }
820
821 int
Curl_sec_request_prot(struct connectdata * conn,const char * level)822 Curl_sec_request_prot(struct connectdata *conn, const char *level)
823 {
824 unsigned char l = name_to_level(level);
825 if(l == PROT_NONE)
826 return -1;
827 DEBUGASSERT(l > PROT_NONE && l < PROT_LAST);
828 conn->request_data_prot = l;
829 return 0;
830 }
831
choose_mech(struct Curl_easy * data,struct connectdata * conn)832 static CURLcode choose_mech(struct Curl_easy *data, struct connectdata *conn)
833 {
834 int ret;
835 void *tmp_allocation;
836 const struct Curl_sec_client_mech *mech = &Curl_krb5_client_mech;
837
838 tmp_allocation = realloc(conn->app_data, mech->size);
839 if(!tmp_allocation) {
840 failf(data, "Failed realloc of size %zu", mech->size);
841 mech = NULL;
842 return CURLE_OUT_OF_MEMORY;
843 }
844 conn->app_data = tmp_allocation;
845
846 if(mech->init) {
847 ret = mech->init(conn->app_data);
848 if(ret) {
849 infof(data, "Failed initialization for %s. Skipping it.",
850 mech->name);
851 return CURLE_FAILED_INIT;
852 }
853 Curl_dyn_init(&conn->in_buffer.buf, CURL_MAX_INPUT_LENGTH);
854 }
855
856 infof(data, "Trying mechanism %s...", mech->name);
857 ret = ftp_send_command(data, "AUTH %s", mech->name);
858 if(ret < 0)
859 return CURLE_COULDNT_CONNECT;
860
861 if(ret/100 != 3) {
862 switch(ret) {
863 case 504:
864 infof(data, "Mechanism %s is not supported by the server (server "
865 "returned ftp code: 504).", mech->name);
866 break;
867 case 534:
868 infof(data, "Mechanism %s was rejected by the server (server returned "
869 "ftp code: 534).", mech->name);
870 break;
871 default:
872 if(ret/100 == 5) {
873 infof(data, "server does not support the security extensions");
874 return CURLE_USE_SSL_FAILED;
875 }
876 break;
877 }
878 return CURLE_LOGIN_DENIED;
879 }
880
881 /* Authenticate */
882 ret = mech->auth(conn->app_data, data, conn);
883
884 if(ret != AUTH_CONTINUE) {
885 if(ret != AUTH_OK) {
886 /* Mechanism has dumped the error to stderr, do not error here. */
887 return CURLE_USE_SSL_FAILED;
888 }
889 DEBUGASSERT(ret == AUTH_OK);
890
891 conn->mech = mech;
892 conn->sec_complete = 1;
893 conn->recv[FIRSTSOCKET] = sec_recv;
894 conn->send[FIRSTSOCKET] = sec_send;
895 conn->recv[SECONDARYSOCKET] = sec_recv;
896 conn->send[SECONDARYSOCKET] = sec_send;
897 conn->command_prot = PROT_SAFE;
898 /* Set the requested protection level */
899 /* BLOCKING */
900 (void)sec_set_protection_level(data);
901 }
902
903 return CURLE_OK;
904 }
905
906 CURLcode
Curl_sec_login(struct Curl_easy * data,struct connectdata * conn)907 Curl_sec_login(struct Curl_easy *data, struct connectdata *conn)
908 {
909 return choose_mech(data, conn);
910 }
911
912
913 void
Curl_sec_end(struct connectdata * conn)914 Curl_sec_end(struct connectdata *conn)
915 {
916 if(conn->mech && conn->mech->end)
917 conn->mech->end(conn->app_data);
918 Curl_safefree(conn->app_data);
919 Curl_dyn_free(&conn->in_buffer.buf);
920 conn->in_buffer.index = 0;
921 conn->in_buffer.eof_flag = 0;
922 conn->sec_complete = 0;
923 conn->data_prot = PROT_CLEAR;
924 conn->mech = NULL;
925 }
926
927 #endif /* HAVE_GSSAPI && !CURL_DISABLE_FTP */
928
