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 Kungliga Tekniska H�gskolan
11 * (Royal Institute of Technology, Stockholm, Sweden).
12 *
13 * Copyright (C) 2001 - 2015, 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 #ifdef HAVE_LIMITS_H
54 #include <limits.h>
55 #endif
56
57 #include "urldata.h"
58 #include "curl_base64.h"
59 #include "curl_memory.h"
60 #include "curl_sec.h"
61 #include "ftp.h"
62 #include "sendf.h"
63 #include "strcase.h"
64 #include "warnless.h"
65 #include "strdup.h"
66 /* The last #include file should be: */
67 #include "memdebug.h"
68
69 static 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
79 static enum protection_level
name_to_level(const char * name)80 name_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. */
level_to_char(int level)91 static 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. */
ftp_send_command(struct connectdata * conn,const char * message,...)115 static 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 vsnprintf(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. */
140 static CURLcode
socket_read(curl_socket_t fd,void * to,size_t len)141 socket_read(curl_socket_t fd, void *to, size_t len)
142 {
143 char *to_p = to;
144 CURLcode result;
145 ssize_t nread;
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 /* FIXME: We are doing a busy wait */
155 if(result == CURLE_AGAIN)
156 continue;
157 return result;
158 }
159 }
160 return CURLE_OK;
161 }
162
163
164 /* Write |len| bytes from the buffer |to| to the socket |fd|. Return a
165 CURLcode saying whether an error occurred or CURLE_OK if |len| was
166 written. */
167 static CURLcode
socket_write(struct connectdata * conn,curl_socket_t fd,const void * to,size_t len)168 socket_write(struct connectdata *conn, curl_socket_t fd, const void *to,
169 size_t len)
170 {
171 const char *to_p = to;
172 CURLcode result;
173 ssize_t written;
174
175 while(len > 0) {
176 result = Curl_write_plain(conn, fd, to_p, len, &written);
177 if(!result) {
178 len -= written;
179 to_p += written;
180 }
181 else {
182 /* FIXME: We are doing a busy wait */
183 if(result == CURLE_AGAIN)
184 continue;
185 return result;
186 }
187 }
188 return CURLE_OK;
189 }
190
read_data(struct connectdata * conn,curl_socket_t fd,struct krb5buffer * buf)191 static CURLcode read_data(struct connectdata *conn,
192 curl_socket_t fd,
193 struct krb5buffer *buf)
194 {
195 int len;
196 void *tmp = NULL;
197 CURLcode result;
198
199 result = socket_read(fd, &len, sizeof(len));
200 if(result)
201 return result;
202
203 if(len) {
204 /* only realloc if there was a length */
205 len = ntohl(len);
206 tmp = Curl_saferealloc(buf->data, len);
207 }
208 if(tmp == NULL)
209 return CURLE_OUT_OF_MEMORY;
210
211 buf->data = tmp;
212 result = socket_read(fd, buf->data, len);
213 if(result)
214 return result;
215 buf->size = conn->mech->decode(conn->app_data, buf->data, len,
216 conn->data_prot, conn);
217 buf->index = 0;
218 return CURLE_OK;
219 }
220
221 static size_t
buffer_read(struct krb5buffer * buf,void * data,size_t len)222 buffer_read(struct krb5buffer *buf, void *data, size_t len)
223 {
224 if(buf->size - buf->index < len)
225 len = buf->size - buf->index;
226 memcpy(data, (char *)buf->data + buf->index, len);
227 buf->index += len;
228 return len;
229 }
230
231 /* Matches Curl_recv signature */
sec_recv(struct connectdata * conn,int sockindex,char * buffer,size_t len,CURLcode * err)232 static ssize_t sec_recv(struct connectdata *conn, int sockindex,
233 char *buffer, size_t len, CURLcode *err)
234 {
235 size_t bytes_read;
236 size_t total_read = 0;
237 curl_socket_t fd = conn->sock[sockindex];
238
239 *err = CURLE_OK;
240
241 /* Handle clear text response. */
242 if(conn->sec_complete == 0 || conn->data_prot == PROT_CLEAR)
243 return read(fd, buffer, len);
244
245 if(conn->in_buffer.eof_flag) {
246 conn->in_buffer.eof_flag = 0;
247 return 0;
248 }
249
250 bytes_read = buffer_read(&conn->in_buffer, buffer, len);
251 len -= bytes_read;
252 total_read += bytes_read;
253 buffer += bytes_read;
254
255 while(len > 0) {
256 if(read_data(conn, fd, &conn->in_buffer))
257 return -1;
258 if(conn->in_buffer.size == 0) {
259 if(bytes_read > 0)
260 conn->in_buffer.eof_flag = 1;
261 return bytes_read;
262 }
263 bytes_read = buffer_read(&conn->in_buffer, buffer, len);
264 len -= bytes_read;
265 total_read += bytes_read;
266 buffer += bytes_read;
267 }
268 /* FIXME: Check for overflow */
269 return total_read;
270 }
271
272 /* Send |length| bytes from |from| to the |fd| socket taking care of encoding
273 and negociating with the server. |from| can be NULL. */
274 /* FIXME: We don't check for errors nor report any! */
do_sec_send(struct connectdata * conn,curl_socket_t fd,const char * from,int length)275 static void do_sec_send(struct connectdata *conn, curl_socket_t fd,
276 const char *from, int length)
277 {
278 int bytes, htonl_bytes; /* 32-bit integers for htonl */
279 char *buffer = NULL;
280 char *cmd_buffer;
281 size_t cmd_size = 0;
282 CURLcode error;
283 enum protection_level prot_level = conn->data_prot;
284 bool iscmd = (prot_level == PROT_CMD)?TRUE:FALSE;
285
286 DEBUGASSERT(prot_level > PROT_NONE && prot_level < PROT_LAST);
287
288 if(iscmd) {
289 if(!strncmp(from, "PASS ", 5) || !strncmp(from, "ACCT ", 5))
290 prot_level = PROT_PRIVATE;
291 else
292 prot_level = conn->command_prot;
293 }
294 bytes = conn->mech->encode(conn->app_data, from, length, prot_level,
295 (void **)&buffer);
296 if(!buffer || bytes <= 0)
297 return; /* error */
298
299 if(iscmd) {
300 error = Curl_base64_encode(conn->data, buffer, curlx_sitouz(bytes),
301 &cmd_buffer, &cmd_size);
302 if(error) {
303 free(buffer);
304 return; /* error */
305 }
306 if(cmd_size > 0) {
307 static const char *enc = "ENC ";
308 static const char *mic = "MIC ";
309 if(prot_level == PROT_PRIVATE)
310 socket_write(conn, fd, enc, 4);
311 else
312 socket_write(conn, fd, mic, 4);
313
314 socket_write(conn, fd, cmd_buffer, cmd_size);
315 socket_write(conn, fd, "\r\n", 2);
316 infof(conn->data, "Send: %s%s\n", prot_level == PROT_PRIVATE?enc:mic,
317 cmd_buffer);
318 free(cmd_buffer);
319 }
320 }
321 else {
322 htonl_bytes = htonl(bytes);
323 socket_write(conn, fd, &htonl_bytes, sizeof(htonl_bytes));
324 socket_write(conn, fd, buffer, curlx_sitouz(bytes));
325 }
326 free(buffer);
327 }
328
sec_write(struct connectdata * conn,curl_socket_t fd,const char * buffer,size_t length)329 static ssize_t sec_write(struct connectdata *conn, curl_socket_t fd,
330 const char *buffer, size_t length)
331 {
332 ssize_t tx = 0, len = conn->buffer_size;
333
334 len -= conn->mech->overhead(conn->app_data, conn->data_prot,
335 curlx_sztosi(len));
336 if(len <= 0)
337 len = length;
338 while(length) {
339 if(length < (size_t)len)
340 len = length;
341
342 do_sec_send(conn, fd, buffer, curlx_sztosi(len));
343 length -= len;
344 buffer += len;
345 tx += len;
346 }
347 return tx;
348 }
349
350 /* Matches Curl_send signature */
sec_send(struct connectdata * conn,int sockindex,const void * buffer,size_t len,CURLcode * err)351 static ssize_t sec_send(struct connectdata *conn, int sockindex,
352 const void *buffer, size_t len, CURLcode *err)
353 {
354 curl_socket_t fd = conn->sock[sockindex];
355 *err = CURLE_OK;
356 return sec_write(conn, fd, buffer, len);
357 }
358
Curl_sec_read_msg(struct connectdata * conn,char * buffer,enum protection_level level)359 int Curl_sec_read_msg(struct connectdata *conn, char *buffer,
360 enum protection_level level)
361 {
362 /* decoded_len should be size_t or ssize_t but conn->mech->decode returns an
363 int */
364 int decoded_len;
365 char *buf;
366 int ret_code = 0;
367 size_t decoded_sz = 0;
368 CURLcode error;
369
370 DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
371
372 error = Curl_base64_decode(buffer + 4, (unsigned char **)&buf, &decoded_sz);
373 if(error || decoded_sz == 0)
374 return -1;
375
376 if(decoded_sz > (size_t)INT_MAX) {
377 free(buf);
378 return -1;
379 }
380 decoded_len = curlx_uztosi(decoded_sz);
381
382 decoded_len = conn->mech->decode(conn->app_data, buf, decoded_len,
383 level, conn);
384 if(decoded_len <= 0) {
385 free(buf);
386 return -1;
387 }
388
389 if(conn->data->set.verbose) {
390 buf[decoded_len] = '\n';
391 Curl_debug(conn->data, CURLINFO_HEADER_IN, buf, decoded_len + 1, conn);
392 }
393
394 buf[decoded_len] = '\0';
395 if(decoded_len <= 3)
396 /* suspiciously short */
397 return 0;
398
399 if(buf[3] != '-')
400 /* safe to ignore return code */
401 (void)sscanf(buf, "%d", &ret_code);
402
403 if(buf[decoded_len - 1] == '\n')
404 buf[decoded_len - 1] = '\0';
405 /* FIXME: Is |buffer| length always greater than |decoded_len|? */
406 strcpy(buffer, buf);
407 free(buf);
408 return ret_code;
409 }
410
411 /* FIXME: The error code returned here is never checked. */
sec_set_protection_level(struct connectdata * conn)412 static int sec_set_protection_level(struct connectdata *conn)
413 {
414 int code;
415 char *pbsz;
416 static unsigned int buffer_size = 1 << 20; /* 1048576 */
417 enum protection_level level = conn->request_data_prot;
418
419 DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
420
421 if(!conn->sec_complete) {
422 infof(conn->data, "Trying to change the protection level after the"
423 "completion of the data exchange.\n");
424 return -1;
425 }
426
427 /* Bail out if we try to set up the same level */
428 if(conn->data_prot == level)
429 return 0;
430
431 if(level) {
432 code = ftp_send_command(conn, "PBSZ %u", buffer_size);
433 if(code < 0)
434 return -1;
435
436 if(code/100 != 2) {
437 failf(conn->data, "Failed to set the protection's buffer size.");
438 return -1;
439 }
440 conn->buffer_size = buffer_size;
441
442 pbsz = strstr(conn->data->state.buffer, "PBSZ=");
443 if(pbsz) {
444 /* ignore return code, use default value if it fails */
445 (void)sscanf(pbsz, "PBSZ=%u", &buffer_size);
446 if(buffer_size < conn->buffer_size)
447 conn->buffer_size = buffer_size;
448 }
449 }
450
451 /* Now try to negiociate the protection level. */
452 code = ftp_send_command(conn, "PROT %c", level_to_char(level));
453
454 if(code < 0)
455 return -1;
456
457 if(code/100 != 2) {
458 failf(conn->data, "Failed to set the protection level.");
459 return -1;
460 }
461
462 conn->data_prot = level;
463 if(level == PROT_PRIVATE)
464 conn->command_prot = level;
465
466 return 0;
467 }
468
469 int
Curl_sec_request_prot(struct connectdata * conn,const char * level)470 Curl_sec_request_prot(struct connectdata *conn, const char *level)
471 {
472 enum protection_level l = name_to_level(level);
473 if(l == PROT_NONE)
474 return -1;
475 DEBUGASSERT(l > PROT_NONE && l < PROT_LAST);
476 conn->request_data_prot = l;
477 return 0;
478 }
479
choose_mech(struct connectdata * conn)480 static CURLcode choose_mech(struct connectdata *conn)
481 {
482 int ret;
483 struct Curl_easy *data = conn->data;
484 void *tmp_allocation;
485 const struct Curl_sec_client_mech *mech = &Curl_krb5_client_mech;
486
487 tmp_allocation = realloc(conn->app_data, mech->size);
488 if(tmp_allocation == NULL) {
489 failf(data, "Failed realloc of size %u", mech->size);
490 mech = NULL;
491 return CURLE_OUT_OF_MEMORY;
492 }
493 conn->app_data = tmp_allocation;
494
495 if(mech->init) {
496 ret = mech->init(conn->app_data);
497 if(ret) {
498 infof(data, "Failed initialization for %s. Skipping it.\n",
499 mech->name);
500 return CURLE_FAILED_INIT;
501 }
502 }
503
504 infof(data, "Trying mechanism %s...\n", mech->name);
505 ret = ftp_send_command(conn, "AUTH %s", mech->name);
506 if(ret < 0)
507 /* FIXME: This error is too generic but it is OK for now. */
508 return CURLE_COULDNT_CONNECT;
509
510 if(ret/100 != 3) {
511 switch(ret) {
512 case 504:
513 infof(data, "Mechanism %s is not supported by the server (server "
514 "returned ftp code: 504).\n", mech->name);
515 break;
516 case 534:
517 infof(data, "Mechanism %s was rejected by the server (server returned "
518 "ftp code: 534).\n", mech->name);
519 break;
520 default:
521 if(ret/100 == 5) {
522 infof(data, "server does not support the security extensions\n");
523 return CURLE_USE_SSL_FAILED;
524 }
525 break;
526 }
527 return CURLE_LOGIN_DENIED;
528 }
529
530 /* Authenticate */
531 ret = mech->auth(conn->app_data, conn);
532
533 if(ret != AUTH_CONTINUE) {
534 if(ret != AUTH_OK) {
535 /* Mechanism has dumped the error to stderr, don't error here. */
536 return -1;
537 }
538 DEBUGASSERT(ret == AUTH_OK);
539
540 conn->mech = mech;
541 conn->sec_complete = 1;
542 conn->recv[FIRSTSOCKET] = sec_recv;
543 conn->send[FIRSTSOCKET] = sec_send;
544 conn->recv[SECONDARYSOCKET] = sec_recv;
545 conn->send[SECONDARYSOCKET] = sec_send;
546 conn->command_prot = PROT_SAFE;
547 /* Set the requested protection level */
548 /* BLOCKING */
549 (void)sec_set_protection_level(conn);
550 }
551
552 return CURLE_OK;
553 }
554
555 CURLcode
Curl_sec_login(struct connectdata * conn)556 Curl_sec_login(struct connectdata *conn)
557 {
558 return choose_mech(conn);
559 }
560
561
562 void
Curl_sec_end(struct connectdata * conn)563 Curl_sec_end(struct connectdata *conn)
564 {
565 if(conn->mech != NULL && conn->mech->end)
566 conn->mech->end(conn->app_data);
567 free(conn->app_data);
568 conn->app_data = NULL;
569 if(conn->in_buffer.data) {
570 free(conn->in_buffer.data);
571 conn->in_buffer.data = NULL;
572 conn->in_buffer.size = 0;
573 conn->in_buffer.index = 0;
574 /* FIXME: Is this really needed? */
575 conn->in_buffer.eof_flag = 0;
576 }
577 conn->sec_complete = 0;
578 conn->data_prot = PROT_CLEAR;
579 conn->mech = NULL;
580 }
581
582 #endif /* HAVE_GSSAPI */
583
584 #endif /* CURL_DISABLE_FTP */
585