Annotation of embedaddon/curl/lib/security.c, revision 1.1.1.1
1.1 misho 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:
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
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. */
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. */
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: 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. */
140: static CURLcode
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 = 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. */
166: static CURLcode
167: socket_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:
189: static 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:
217: static size_t
218: buffer_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 */
228: static 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. */
269: static 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:
323: static 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 */
345: static 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:
353: int 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:
408: static 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:
466: int
467: Curl_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:
477: static 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:
551: CURLcode
552: Curl_sec_login(struct connectdata *conn)
553: {
554: return choose_mech(conn);
555: }
556:
557:
558: void
559: Curl_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 */
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