1/* This source code was modified by Martin Hedenfalk <mhe@stacken.kth.se> for
2 * use in Curl. His latest changes were done 2000-09-18.
3 *
4 * It has since been patched and modified a lot by Daniel Stenberg
5 * <daniel@haxx.se> to make it better applied to curl conditions, and to make
6 * it not use globals, pollute name space and more. This source code awaits a
7 * rewrite to work around the paragraph 2 in the BSD licenses as explained
8 * below.
9 *
10 * Copyright (c) 1998, 1999, 2017 Kungliga Tekniska Högskolan
11 * (Royal Institute of Technology, Stockholm, Sweden).
12 *
13 * Copyright (C) 2001 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
14 *
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 *
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 *
24 * 2. Redistributions in binary form must reproduce the above copyright
25 * notice, this list of conditions and the following disclaimer in the
26 * documentation and/or other materials provided with the distribution.
27 *
28 * 3. Neither the name of the Institute nor the names of its contributors
29 * may be used to endorse or promote products derived from this software
30 * without specific prior written permission.
31 *
32 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42 * SUCH DAMAGE. */
43
44#include "curl_setup.h"
45
46#ifndef CURL_DISABLE_FTP
47#ifdef HAVE_GSSAPI
48
49#ifdef HAVE_NETDB_H
50#include <netdb.h>
51#endif
52
53#include <limits.h>
54
55#include "urldata.h"
56#include "curl_base64.h"
57#include "curl_memory.h"
58#include "curl_sec.h"
59#include "ftp.h"
60#include "sendf.h"
61#include "strcase.h"
62#include "warnless.h"
63#include "strdup.h"
64/* The last 3 #include files should be in this order */
65#include "curl_printf.h"
66#include "curl_memory.h"
67#include "memdebug.h"
68
69static const struct {
70 enum protection_level level;
71 const char *name;
72} level_names[] = {
73 { PROT_CLEAR, "clear" },
74 { PROT_SAFE, "safe" },
75 { PROT_CONFIDENTIAL, "confidential" },
76 { PROT_PRIVATE, "private" }
77};
78
79static enum protection_level
80name_to_level(const char *name)
81{
82 int i;
83 for(i = 0; i < (int)sizeof(level_names)/(int)sizeof(level_names[0]); i++)
84 if(checkprefix(name, level_names[i].name))
85 return level_names[i].level;
86 return PROT_NONE;
87}
88
89/* Convert a protocol |level| to its char representation.
90 We take an int to catch programming mistakes. */
91static char level_to_char(int level)
92{
93 switch(level) {
94 case PROT_CLEAR:
95 return 'C';
96 case PROT_SAFE:
97 return 'S';
98 case PROT_CONFIDENTIAL:
99 return 'E';
100 case PROT_PRIVATE:
101 return 'P';
102 case PROT_CMD:
103 /* Fall through */
104 default:
105 /* Those 2 cases should not be reached! */
106 break;
107 }
108 DEBUGASSERT(0);
109 /* Default to the most secure alternative. */
110 return 'P';
111}
112
113/* Send an FTP command defined by |message| and the optional arguments. The
114 function returns the ftp_code. If an error occurs, -1 is returned. */
115static int ftp_send_command(struct connectdata *conn, const char *message, ...)
116{
117 int ftp_code;
118 ssize_t nread = 0;
119 va_list args;
120 char print_buffer[50];
121
122 va_start(args, message);
123 mvsnprintf(print_buffer, sizeof(print_buffer), message, args);
124 va_end(args);
125
126 if(Curl_ftpsend(conn, print_buffer)) {
127 ftp_code = -1;
128 }
129 else {
130 if(Curl_GetFTPResponse(&nread, conn, &ftp_code))
131 ftp_code = -1;
132 }
133
134 (void)nread; /* Unused */
135 return ftp_code;
136}
137
138/* Read |len| from the socket |fd| and store it in |to|. Return a CURLcode
139 saying whether an error occurred or CURLE_OK if |len| was read. */
140static CURLcode
141socket_read(curl_socket_t fd, void *to, size_t len)
142{
143 char *to_p = to;
144 CURLcode result;
145 ssize_t nread = 0;
146
147 while(len > 0) {
148 result = Curl_read_plain(fd, to_p, len, &nread);
149 if(!result) {
150 len -= nread;
151 to_p += nread;
152 }
153 else {
154 if(result == CURLE_AGAIN)
155 continue;
156 return result;
157 }
158 }
159 return CURLE_OK;
160}
161
162
163/* Write |len| bytes from the buffer |to| to the socket |fd|. Return a
164 CURLcode saying whether an error occurred or CURLE_OK if |len| was
165 written. */
166static CURLcode
167socket_write(struct connectdata *conn, curl_socket_t fd, const void *to,
168 size_t len)
169{
170 const char *to_p = to;
171 CURLcode result;
172 ssize_t written;
173
174 while(len > 0) {
175 result = Curl_write_plain(conn, fd, to_p, len, &written);
176 if(!result) {
177 len -= written;
178 to_p += written;
179 }
180 else {
181 if(result == CURLE_AGAIN)
182 continue;
183 return result;
184 }
185 }
186 return CURLE_OK;
187}
188
189static CURLcode read_data(struct connectdata *conn,
190 curl_socket_t fd,
191 struct krb5buffer *buf)
192{
193 int len;
194 CURLcode result;
195
196 result = socket_read(fd, &len, sizeof(len));
197 if(result)
198 return result;
199
200 if(len) {
201 /* only realloc if there was a length */
202 len = ntohl(len);
203 buf->data = Curl_saferealloc(buf->data, len);
204 }
205 if(!len || !buf->data)
206 return CURLE_OUT_OF_MEMORY;
207
208 result = socket_read(fd, buf->data, len);
209 if(result)
210 return result;
211 buf->size = conn->mech->decode(conn->app_data, buf->data, len,
212 conn->data_prot, conn);
213 buf->index = 0;
214 return CURLE_OK;
215}
216
217static size_t
218buffer_read(struct krb5buffer *buf, void *data, size_t len)
219{
220 if(buf->size - buf->index < len)
221 len = buf->size - buf->index;
222 memcpy(data, (char *)buf->data + buf->index, len);
223 buf->index += len;
224 return len;
225}
226
227/* Matches Curl_recv signature */
228static ssize_t sec_recv(struct connectdata *conn, int sockindex,
229 char *buffer, size_t len, CURLcode *err)
230{
231 size_t bytes_read;
232 size_t total_read = 0;
233 curl_socket_t fd = conn->sock[sockindex];
234
235 *err = CURLE_OK;
236
237 /* Handle clear text response. */
238 if(conn->sec_complete == 0 || conn->data_prot == PROT_CLEAR)
239 return sread(fd, buffer, len);
240
241 if(conn->in_buffer.eof_flag) {
242 conn->in_buffer.eof_flag = 0;
243 return 0;
244 }
245
246 bytes_read = buffer_read(&conn->in_buffer, buffer, len);
247 len -= bytes_read;
248 total_read += bytes_read;
249 buffer += bytes_read;
250
251 while(len > 0) {
252 if(read_data(conn, fd, &conn->in_buffer))
253 return -1;
254 if(conn->in_buffer.size == 0) {
255 if(bytes_read > 0)
256 conn->in_buffer.eof_flag = 1;
257 return bytes_read;
258 }
259 bytes_read = buffer_read(&conn->in_buffer, buffer, len);
260 len -= bytes_read;
261 total_read += bytes_read;
262 buffer += bytes_read;
263 }
264 return total_read;
265}
266
267/* Send |length| bytes from |from| to the |fd| socket taking care of encoding
268 and negotiating with the server. |from| can be NULL. */
269static void do_sec_send(struct connectdata *conn, curl_socket_t fd,
270 const char *from, int length)
271{
272 int bytes, htonl_bytes; /* 32-bit integers for htonl */
273 char *buffer = NULL;
274 char *cmd_buffer;
275 size_t cmd_size = 0;
276 CURLcode error;
277 enum protection_level prot_level = conn->data_prot;
278 bool iscmd = (prot_level == PROT_CMD)?TRUE:FALSE;
279
280 DEBUGASSERT(prot_level > PROT_NONE && prot_level < PROT_LAST);
281
282 if(iscmd) {
283 if(!strncmp(from, "PASS ", 5) || !strncmp(from, "ACCT ", 5))
284 prot_level = PROT_PRIVATE;
285 else
286 prot_level = conn->command_prot;
287 }
288 bytes = conn->mech->encode(conn->app_data, from, length, prot_level,
289 (void **)&buffer);
290 if(!buffer || bytes <= 0)
291 return; /* error */
292
293 if(iscmd) {
294 error = Curl_base64_encode(conn->data, buffer, curlx_sitouz(bytes),
295 &cmd_buffer, &cmd_size);
296 if(error) {
297 free(buffer);
298 return; /* error */
299 }
300 if(cmd_size > 0) {
301 static const char *enc = "ENC ";
302 static const char *mic = "MIC ";
303 if(prot_level == PROT_PRIVATE)
304 socket_write(conn, fd, enc, 4);
305 else
306 socket_write(conn, fd, mic, 4);
307
308 socket_write(conn, fd, cmd_buffer, cmd_size);
309 socket_write(conn, fd, "\r\n", 2);
310 infof(conn->data, "Send: %s%s\n", prot_level == PROT_PRIVATE?enc:mic,
311 cmd_buffer);
312 free(cmd_buffer);
313 }
314 }
315 else {
316 htonl_bytes = htonl(bytes);
317 socket_write(conn, fd, &htonl_bytes, sizeof(htonl_bytes));
318 socket_write(conn, fd, buffer, curlx_sitouz(bytes));
319 }
320 free(buffer);
321}
322
323static ssize_t sec_write(struct connectdata *conn, curl_socket_t fd,
324 const char *buffer, size_t length)
325{
326 ssize_t tx = 0, len = conn->buffer_size;
327
328 len -= conn->mech->overhead(conn->app_data, conn->data_prot,
329 curlx_sztosi(len));
330 if(len <= 0)
331 len = length;
332 while(length) {
333 if(length < (size_t)len)
334 len = length;
335
336 do_sec_send(conn, fd, buffer, curlx_sztosi(len));
337 length -= len;
338 buffer += len;
339 tx += len;
340 }
341 return tx;
342}
343
344/* Matches Curl_send signature */
345static ssize_t sec_send(struct connectdata *conn, int sockindex,
346 const void *buffer, size_t len, CURLcode *err)
347{
348 curl_socket_t fd = conn->sock[sockindex];
349 *err = CURLE_OK;
350 return sec_write(conn, fd, buffer, len);
351}
352
353int Curl_sec_read_msg(struct connectdata *conn, char *buffer,
354 enum protection_level level)
355{
356 /* decoded_len should be size_t or ssize_t but conn->mech->decode returns an
357 int */
358 int decoded_len;
359 char *buf;
360 int ret_code = 0;
361 size_t decoded_sz = 0;
362 CURLcode error;
363
364 if(!conn->mech)
365 /* not inititalized, return error */
366 return -1;
367
368 DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
369
370 error = Curl_base64_decode(buffer + 4, (unsigned char **)&buf, &decoded_sz);
371 if(error || decoded_sz == 0)
372 return -1;
373
374 if(decoded_sz > (size_t)INT_MAX) {
375 free(buf);
376 return -1;
377 }
378 decoded_len = curlx_uztosi(decoded_sz);
379
380 decoded_len = conn->mech->decode(conn->app_data, buf, decoded_len,
381 level, conn);
382 if(decoded_len <= 0) {
383 free(buf);
384 return -1;
385 }
386
387 if(conn->data->set.verbose) {
388 buf[decoded_len] = '\n';
389 Curl_debug(conn->data, CURLINFO_HEADER_IN, buf, decoded_len + 1);
390 }
391
392 buf[decoded_len] = '\0';
393 if(decoded_len <= 3)
394 /* suspiciously short */
395 return 0;
396
397 if(buf[3] != '-')
398 /* safe to ignore return code */
399 (void)sscanf(buf, "%d", &ret_code);
400
401 if(buf[decoded_len - 1] == '\n')
402 buf[decoded_len - 1] = '\0';
403 strcpy(buffer, buf);
404 free(buf);
405 return ret_code;
406}
407
408static int sec_set_protection_level(struct connectdata *conn)
409{
410 int code;
411 enum protection_level level = conn->request_data_prot;
412
413 DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
414
415 if(!conn->sec_complete) {
416 infof(conn->data, "Trying to change the protection level after the"
417 " completion of the data exchange.\n");
418 return -1;
419 }
420
421 /* Bail out if we try to set up the same level */
422 if(conn->data_prot == level)
423 return 0;
424
425 if(level) {
426 char *pbsz;
427 static unsigned int buffer_size = 1 << 20; /* 1048576 */
428
429 code = ftp_send_command(conn, "PBSZ %u", buffer_size);
430 if(code < 0)
431 return -1;
432
433 if(code/100 != 2) {
434 failf(conn->data, "Failed to set the protection's buffer size.");
435 return -1;
436 }
437 conn->buffer_size = buffer_size;
438
439 pbsz = strstr(conn->data->state.buffer, "PBSZ=");
440 if(pbsz) {
441 /* ignore return code, use default value if it fails */
442 (void)sscanf(pbsz, "PBSZ=%u", &buffer_size);
443 if(buffer_size < conn->buffer_size)
444 conn->buffer_size = buffer_size;
445 }
446 }
447
448 /* Now try to negiociate the protection level. */
449 code = ftp_send_command(conn, "PROT %c", level_to_char(level));
450
451 if(code < 0)
452 return -1;
453
454 if(code/100 != 2) {
455 failf(conn->data, "Failed to set the protection level.");
456 return -1;
457 }
458
459 conn->data_prot = level;
460 if(level == PROT_PRIVATE)
461 conn->command_prot = level;
462
463 return 0;
464}
465
466int
467Curl_sec_request_prot(struct connectdata *conn, const char *level)
468{
469 enum protection_level l = name_to_level(level);
470 if(l == PROT_NONE)
471 return -1;
472 DEBUGASSERT(l > PROT_NONE && l < PROT_LAST);
473 conn->request_data_prot = l;
474 return 0;
475}
476
477static CURLcode choose_mech(struct connectdata *conn)
478{
479 int ret;
480 struct Curl_easy *data = conn->data;
481 void *tmp_allocation;
482 const struct Curl_sec_client_mech *mech = &Curl_krb5_client_mech;
483
484 tmp_allocation = realloc(conn->app_data, mech->size);
485 if(tmp_allocation == NULL) {
486 failf(data, "Failed realloc of size %zu", mech->size);
487 mech = NULL;
488 return CURLE_OUT_OF_MEMORY;
489 }
490 conn->app_data = tmp_allocation;
491
492 if(mech->init) {
493 ret = mech->init(conn->app_data);
494 if(ret) {
495 infof(data, "Failed initialization for %s. Skipping it.\n",
496 mech->name);
497 return CURLE_FAILED_INIT;
498 }
499 }
500
501 infof(data, "Trying mechanism %s...\n", mech->name);
502 ret = ftp_send_command(conn, "AUTH %s", mech->name);
503 if(ret < 0)
504 return CURLE_COULDNT_CONNECT;
505
506 if(ret/100 != 3) {
507 switch(ret) {
508 case 504:
509 infof(data, "Mechanism %s is not supported by the server (server "
510 "returned ftp code: 504).\n", mech->name);
511 break;
512 case 534:
513 infof(data, "Mechanism %s was rejected by the server (server returned "
514 "ftp code: 534).\n", mech->name);
515 break;
516 default:
517 if(ret/100 == 5) {
518 infof(data, "server does not support the security extensions\n");
519 return CURLE_USE_SSL_FAILED;
520 }
521 break;
522 }
523 return CURLE_LOGIN_DENIED;
524 }
525
526 /* Authenticate */
527 ret = mech->auth(conn->app_data, conn);
528
529 if(ret != AUTH_CONTINUE) {
530 if(ret != AUTH_OK) {
531 /* Mechanism has dumped the error to stderr, don't error here. */
532 return -1;
533 }
534 DEBUGASSERT(ret == AUTH_OK);
535
536 conn->mech = mech;
537 conn->sec_complete = 1;
538 conn->recv[FIRSTSOCKET] = sec_recv;
539 conn->send[FIRSTSOCKET] = sec_send;
540 conn->recv[SECONDARYSOCKET] = sec_recv;
541 conn->send[SECONDARYSOCKET] = sec_send;
542 conn->command_prot = PROT_SAFE;
543 /* Set the requested protection level */
544 /* BLOCKING */
545 (void)sec_set_protection_level(conn);
546 }
547
548 return CURLE_OK;
549}
550
551CURLcode
552Curl_sec_login(struct connectdata *conn)
553{
554 return choose_mech(conn);
555}
556
557
558void
559Curl_sec_end(struct connectdata *conn)
560{
561 if(conn->mech != NULL && conn->mech->end)
562 conn->mech->end(conn->app_data);
563 free(conn->app_data);
564 conn->app_data = NULL;
565 if(conn->in_buffer.data) {
566 free(conn->in_buffer.data);
567 conn->in_buffer.data = NULL;
568 conn->in_buffer.size = 0;
569 conn->in_buffer.index = 0;
570 conn->in_buffer.eof_flag = 0;
571 }
572 conn->sec_complete = 0;
573 conn->data_prot = PROT_CLEAR;
574 conn->mech = NULL;
575}
576
577#endif /* HAVE_GSSAPI */
578
579#endif /* CURL_DISABLE_FTP */
580