1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 2012 - 2016, Marc Hoersken, <info@marc-hoersken.de>
9 * Copyright (C) 2012, Mark Salisbury, <mark.salisbury@hp.com>
10 * Copyright (C) 2012 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
11 *
12 * This software is licensed as described in the file COPYING, which
13 * you should have received as part of this distribution. The terms
14 * are also available at https://curl.haxx.se/docs/copyright.html.
15 *
16 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
17 * copies of the Software, and permit persons to whom the Software is
18 * furnished to do so, under the terms of the COPYING file.
19 *
20 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
21 * KIND, either express or implied.
22 *
23 ***************************************************************************/
24
25 /*
26 * Source file for Schannel-specific certificate verification. This code should
27 * only be invoked by code in schannel.c.
28 */
29
30 #include "curl_setup.h"
31
32 #ifdef USE_SCHANNEL
33 #ifndef USE_WINDOWS_SSPI
34 # error "Can't compile SCHANNEL support without SSPI."
35 #endif
36
37 #define EXPOSE_SCHANNEL_INTERNAL_STRUCTS
38 #include "schannel.h"
39
40 #ifdef HAS_MANUAL_VERIFY_API
41
42 #include "vtls.h"
43 #include "sendf.h"
44 #include "strerror.h"
45 #include "curl_multibyte.h"
46 #include "curl_printf.h"
47 #include "hostcheck.h"
48 #include "system_win32.h"
49
50 /* The last #include file should be: */
51 #include "curl_memory.h"
52 #include "memdebug.h"
53
54 #define BACKEND connssl->backend
55
56 #define MAX_CAFILE_SIZE 1048576 /* 1 MiB */
57 #define BEGIN_CERT "-----BEGIN CERTIFICATE-----"
58 #define END_CERT "\n-----END CERTIFICATE-----"
59
60 typedef struct {
61 DWORD cbSize;
62 HCERTSTORE hRestrictedRoot;
63 HCERTSTORE hRestrictedTrust;
64 HCERTSTORE hRestrictedOther;
65 DWORD cAdditionalStore;
66 HCERTSTORE *rghAdditionalStore;
67 DWORD dwFlags;
68 DWORD dwUrlRetrievalTimeout;
69 DWORD MaximumCachedCertificates;
70 DWORD CycleDetectionModulus;
71 HCERTSTORE hExclusiveRoot;
72 HCERTSTORE hExclusiveTrustedPeople;
73 } CERT_CHAIN_ENGINE_CONFIG_WIN7, *PCERT_CHAIN_ENGINE_CONFIG_WIN7;
74
is_cr_or_lf(char c)75 static int is_cr_or_lf(char c)
76 {
77 return c == '\r' || c == '\n';
78 }
79
add_certs_to_store(HCERTSTORE trust_store,const char * ca_file,struct connectdata * conn)80 static CURLcode add_certs_to_store(HCERTSTORE trust_store,
81 const char *ca_file,
82 struct connectdata *conn)
83 {
84 CURLcode result;
85 struct Curl_easy *data = conn->data;
86 HANDLE ca_file_handle = INVALID_HANDLE_VALUE;
87 LARGE_INTEGER file_size;
88 char *ca_file_buffer = NULL;
89 char *current_ca_file_ptr = NULL;
90 TCHAR *ca_file_tstr = NULL;
91 size_t ca_file_bufsize = 0;
92 DWORD total_bytes_read = 0;
93 bool more_certs = 0;
94 int num_certs = 0;
95 size_t END_CERT_LEN;
96
97 ca_file_tstr = Curl_convert_UTF8_to_tchar((char *)ca_file);
98 if(!ca_file_tstr) {
99 char buffer[STRERROR_LEN];
100 failf(data,
101 "schannel: invalid path name for CA file '%s': %s",
102 ca_file, Curl_strerror(GetLastError(), buffer, sizeof(buffer)));
103 result = CURLE_SSL_CACERT_BADFILE;
104 goto cleanup;
105 }
106
107 /*
108 * Read the CA file completely into memory before parsing it. This
109 * optimizes for the common case where the CA file will be relatively
110 * small ( < 1 MiB ).
111 */
112 ca_file_handle = CreateFile(ca_file_tstr,
113 GENERIC_READ,
114 0,
115 NULL,
116 OPEN_EXISTING,
117 FILE_ATTRIBUTE_NORMAL,
118 NULL);
119 if(ca_file_handle == INVALID_HANDLE_VALUE) {
120 char buffer[STRERROR_LEN];
121 failf(data,
122 "schannel: failed to open CA file '%s': %s",
123 ca_file, Curl_strerror(GetLastError(), buffer, sizeof(buffer)));
124 result = CURLE_SSL_CACERT_BADFILE;
125 goto cleanup;
126 }
127
128 if(!GetFileSizeEx(ca_file_handle, &file_size)) {
129 char buffer[STRERROR_LEN];
130 failf(data,
131 "schannel: failed to determine size of CA file '%s': %s",
132 ca_file, Curl_strerror(GetLastError(), buffer, sizeof(buffer)));
133 result = CURLE_SSL_CACERT_BADFILE;
134 goto cleanup;
135 }
136
137 if(file_size.QuadPart > MAX_CAFILE_SIZE) {
138 failf(data,
139 "schannel: CA file exceeds max size of %u bytes",
140 MAX_CAFILE_SIZE);
141 result = CURLE_SSL_CACERT_BADFILE;
142 goto cleanup;
143 }
144
145 ca_file_bufsize = (size_t)file_size.QuadPart;
146 ca_file_buffer = (char *)malloc(ca_file_bufsize + 1);
147 if(!ca_file_buffer) {
148 result = CURLE_OUT_OF_MEMORY;
149 goto cleanup;
150 }
151
152 result = CURLE_OK;
153 while(total_bytes_read < ca_file_bufsize) {
154 DWORD bytes_to_read = (DWORD)(ca_file_bufsize - total_bytes_read);
155 DWORD bytes_read = 0;
156
157 if(!ReadFile(ca_file_handle, ca_file_buffer + total_bytes_read,
158 bytes_to_read, &bytes_read, NULL)) {
159 char buffer[STRERROR_LEN];
160 failf(data,
161 "schannel: failed to read from CA file '%s': %s",
162 ca_file, Curl_strerror(GetLastError(), buffer, sizeof(buffer)));
163 result = CURLE_SSL_CACERT_BADFILE;
164 goto cleanup;
165 }
166 if(bytes_read == 0) {
167 /* Premature EOF -- adjust the bufsize to the new value */
168 ca_file_bufsize = total_bytes_read;
169 }
170 else {
171 total_bytes_read += bytes_read;
172 }
173 }
174
175 /* Null terminate the buffer */
176 ca_file_buffer[ca_file_bufsize] = '\0';
177
178 if(result != CURLE_OK) {
179 goto cleanup;
180 }
181
182 END_CERT_LEN = strlen(END_CERT);
183
184 more_certs = 1;
185 current_ca_file_ptr = ca_file_buffer;
186 while(more_certs && *current_ca_file_ptr != '\0') {
187 char *begin_cert_ptr = strstr(current_ca_file_ptr, BEGIN_CERT);
188 if(!begin_cert_ptr || !is_cr_or_lf(begin_cert_ptr[strlen(BEGIN_CERT)])) {
189 more_certs = 0;
190 }
191 else {
192 char *end_cert_ptr = strstr(begin_cert_ptr, END_CERT);
193 if(!end_cert_ptr) {
194 failf(data,
195 "schannel: CA file '%s' is not correctly formatted",
196 ca_file);
197 result = CURLE_SSL_CACERT_BADFILE;
198 more_certs = 0;
199 }
200 else {
201 CERT_BLOB cert_blob;
202 CERT_CONTEXT *cert_context = NULL;
203 BOOL add_cert_result = FALSE;
204 DWORD actual_content_type = 0;
205 DWORD cert_size = (DWORD)
206 ((end_cert_ptr + END_CERT_LEN) - begin_cert_ptr);
207
208 cert_blob.pbData = (BYTE *)begin_cert_ptr;
209 cert_blob.cbData = cert_size;
210 if(!CryptQueryObject(CERT_QUERY_OBJECT_BLOB,
211 &cert_blob,
212 CERT_QUERY_CONTENT_FLAG_CERT,
213 CERT_QUERY_FORMAT_FLAG_ALL,
214 0,
215 NULL,
216 &actual_content_type,
217 NULL,
218 NULL,
219 NULL,
220 (const void **)&cert_context)) {
221 char buffer[STRERROR_LEN];
222 failf(data,
223 "schannel: failed to extract certificate from CA file "
224 "'%s': %s",
225 ca_file,
226 Curl_strerror(GetLastError(), buffer, sizeof(buffer)));
227 result = CURLE_SSL_CACERT_BADFILE;
228 more_certs = 0;
229 }
230 else {
231 current_ca_file_ptr = begin_cert_ptr + cert_size;
232
233 /* Sanity check that the cert_context object is the right type */
234 if(CERT_QUERY_CONTENT_CERT != actual_content_type) {
235 failf(data,
236 "schannel: unexpected content type '%d' when extracting "
237 "certificate from CA file '%s'",
238 actual_content_type, ca_file);
239 result = CURLE_SSL_CACERT_BADFILE;
240 more_certs = 0;
241 }
242 else {
243 add_cert_result =
244 CertAddCertificateContextToStore(trust_store,
245 cert_context,
246 CERT_STORE_ADD_ALWAYS,
247 NULL);
248 CertFreeCertificateContext(cert_context);
249 if(!add_cert_result) {
250 char buffer[STRERROR_LEN];
251 failf(data,
252 "schannel: failed to add certificate from CA file '%s' "
253 "to certificate store: %s",
254 ca_file,
255 Curl_strerror(GetLastError(), buffer, sizeof(buffer)));
256 result = CURLE_SSL_CACERT_BADFILE;
257 more_certs = 0;
258 }
259 else {
260 num_certs++;
261 }
262 }
263 }
264 }
265 }
266 }
267
268 if(result == CURLE_OK) {
269 if(!num_certs) {
270 infof(data,
271 "schannel: did not add any certificates from CA file '%s'\n",
272 ca_file);
273 }
274 else {
275 infof(data,
276 "schannel: added %d certificate(s) from CA file '%s'\n",
277 num_certs, ca_file);
278 }
279 }
280
281 cleanup:
282 if(ca_file_handle != INVALID_HANDLE_VALUE) {
283 CloseHandle(ca_file_handle);
284 }
285 Curl_safefree(ca_file_buffer);
286 Curl_unicodefree(ca_file_tstr);
287
288 return result;
289 }
290
verify_host(struct Curl_easy * data,CERT_CONTEXT * pCertContextServer,const char * const conn_hostname)291 static CURLcode verify_host(struct Curl_easy *data,
292 CERT_CONTEXT *pCertContextServer,
293 const char * const conn_hostname)
294 {
295 CURLcode result = CURLE_PEER_FAILED_VERIFICATION;
296 TCHAR *cert_hostname_buff = NULL;
297 size_t cert_hostname_buff_index = 0;
298 DWORD len = 0;
299 DWORD actual_len = 0;
300
301 /* CertGetNameString will provide the 8-bit character string without
302 * any decoding */
303 DWORD name_flags = CERT_NAME_DISABLE_IE4_UTF8_FLAG;
304
305 #ifdef CERT_NAME_SEARCH_ALL_NAMES_FLAG
306 name_flags |= CERT_NAME_SEARCH_ALL_NAMES_FLAG;
307 #endif
308
309 /* Determine the size of the string needed for the cert hostname */
310 len = CertGetNameString(pCertContextServer,
311 CERT_NAME_DNS_TYPE,
312 name_flags,
313 NULL,
314 NULL,
315 0);
316 if(len == 0) {
317 failf(data,
318 "schannel: CertGetNameString() returned no "
319 "certificate name information");
320 result = CURLE_PEER_FAILED_VERIFICATION;
321 goto cleanup;
322 }
323
324 /* CertGetNameString guarantees that the returned name will not contain
325 * embedded null bytes. This appears to be undocumented behavior.
326 */
327 cert_hostname_buff = (LPTSTR)malloc(len * sizeof(TCHAR));
328 if(!cert_hostname_buff) {
329 result = CURLE_OUT_OF_MEMORY;
330 goto cleanup;
331 }
332 actual_len = CertGetNameString(pCertContextServer,
333 CERT_NAME_DNS_TYPE,
334 name_flags,
335 NULL,
336 (LPTSTR) cert_hostname_buff,
337 len);
338
339 /* Sanity check */
340 if(actual_len != len) {
341 failf(data,
342 "schannel: CertGetNameString() returned certificate "
343 "name information of unexpected size");
344 result = CURLE_PEER_FAILED_VERIFICATION;
345 goto cleanup;
346 }
347
348 /* If HAVE_CERT_NAME_SEARCH_ALL_NAMES is available, the output
349 * will contain all DNS names, where each name is null-terminated
350 * and the last DNS name is double null-terminated. Due to this
351 * encoding, use the length of the buffer to iterate over all names.
352 */
353 result = CURLE_PEER_FAILED_VERIFICATION;
354 while(cert_hostname_buff_index < len &&
355 cert_hostname_buff[cert_hostname_buff_index] != TEXT('\0') &&
356 result == CURLE_PEER_FAILED_VERIFICATION) {
357
358 char *cert_hostname;
359
360 /* Comparing the cert name and the connection hostname encoded as UTF-8
361 * is acceptable since both values are assumed to use ASCII
362 * (or some equivalent) encoding
363 */
364 cert_hostname = Curl_convert_tchar_to_UTF8(
365 &cert_hostname_buff[cert_hostname_buff_index]);
366 if(!cert_hostname) {
367 result = CURLE_OUT_OF_MEMORY;
368 }
369 else {
370 int match_result;
371
372 match_result = Curl_cert_hostcheck(cert_hostname, conn_hostname);
373 if(match_result == CURL_HOST_MATCH) {
374 infof(data,
375 "schannel: connection hostname (%s) validated "
376 "against certificate name (%s)\n",
377 conn_hostname, cert_hostname);
378 result = CURLE_OK;
379 }
380 else {
381 size_t cert_hostname_len;
382
383 infof(data,
384 "schannel: connection hostname (%s) did not match "
385 "against certificate name (%s)\n",
386 conn_hostname, cert_hostname);
387
388 cert_hostname_len = _tcslen(
389 &cert_hostname_buff[cert_hostname_buff_index]);
390
391 /* Move on to next cert name */
392 cert_hostname_buff_index += cert_hostname_len + 1;
393
394 result = CURLE_PEER_FAILED_VERIFICATION;
395 }
396 Curl_unicodefree(cert_hostname);
397 }
398 }
399
400 if(result == CURLE_PEER_FAILED_VERIFICATION) {
401 failf(data,
402 "schannel: CertGetNameString() failed to match "
403 "connection hostname (%s) against server certificate names",
404 conn_hostname);
405 }
406 else if(result != CURLE_OK)
407 failf(data, "schannel: server certificate name verification failed");
408
409 cleanup:
410 Curl_unicodefree(cert_hostname_buff);
411
412 return result;
413 }
414
Curl_verify_certificate(struct connectdata * conn,int sockindex)415 CURLcode Curl_verify_certificate(struct connectdata *conn, int sockindex)
416 {
417 SECURITY_STATUS sspi_status;
418 struct Curl_easy *data = conn->data;
419 struct ssl_connect_data *connssl = &conn->ssl[sockindex];
420 CURLcode result = CURLE_OK;
421 CERT_CONTEXT *pCertContextServer = NULL;
422 const CERT_CHAIN_CONTEXT *pChainContext = NULL;
423 HCERTCHAINENGINE cert_chain_engine = NULL;
424 HCERTSTORE trust_store = NULL;
425 const char * const conn_hostname = SSL_IS_PROXY() ?
426 conn->http_proxy.host.name :
427 conn->host.name;
428
429 sspi_status =
430 s_pSecFn->QueryContextAttributes(&BACKEND->ctxt->ctxt_handle,
431 SECPKG_ATTR_REMOTE_CERT_CONTEXT,
432 &pCertContextServer);
433
434 if((sspi_status != SEC_E_OK) || (pCertContextServer == NULL)) {
435 char buffer[STRERROR_LEN];
436 failf(data, "schannel: Failed to read remote certificate context: %s",
437 Curl_sspi_strerror(sspi_status, buffer, sizeof(buffer)));
438 result = CURLE_PEER_FAILED_VERIFICATION;
439 }
440
441 if(result == CURLE_OK && SSL_CONN_CONFIG(CAfile) &&
442 BACKEND->use_manual_cred_validation) {
443 /*
444 * Create a chain engine that uses the certificates in the CA file as
445 * trusted certificates. This is only supported on Windows 7+.
446 */
447
448 if(Curl_verify_windows_version(6, 1, PLATFORM_WINNT, VERSION_LESS_THAN)) {
449 failf(data, "schannel: this version of Windows is too old to support "
450 "certificate verification via CA bundle file.");
451 result = CURLE_SSL_CACERT_BADFILE;
452 }
453 else {
454 /* Open the certificate store */
455 trust_store = CertOpenStore(CERT_STORE_PROV_MEMORY,
456 0,
457 (HCRYPTPROV)NULL,
458 CERT_STORE_CREATE_NEW_FLAG,
459 NULL);
460 if(!trust_store) {
461 char buffer[STRERROR_LEN];
462 failf(data, "schannel: failed to create certificate store: %s",
463 Curl_strerror(GetLastError(), buffer, sizeof(buffer)));
464 result = CURLE_SSL_CACERT_BADFILE;
465 }
466 else {
467 result = add_certs_to_store(trust_store, SSL_CONN_CONFIG(CAfile),
468 conn);
469 }
470 }
471
472 if(result == CURLE_OK) {
473 CERT_CHAIN_ENGINE_CONFIG_WIN7 engine_config;
474 BOOL create_engine_result;
475
476 memset(&engine_config, 0, sizeof(engine_config));
477 engine_config.cbSize = sizeof(engine_config);
478 engine_config.hExclusiveRoot = trust_store;
479
480 /* CertCreateCertificateChainEngine will check the expected size of the
481 * CERT_CHAIN_ENGINE_CONFIG structure and fail if the specified size
482 * does not match the expected size. When this occurs, it indicates that
483 * CAINFO is not supported on the version of Windows in use.
484 */
485 create_engine_result =
486 CertCreateCertificateChainEngine(
487 (CERT_CHAIN_ENGINE_CONFIG *)&engine_config, &cert_chain_engine);
488 if(!create_engine_result) {
489 char buffer[STRERROR_LEN];
490 failf(data,
491 "schannel: failed to create certificate chain engine: %s",
492 Curl_strerror(GetLastError(), buffer, sizeof(buffer)));
493 result = CURLE_SSL_CACERT_BADFILE;
494 }
495 }
496 }
497
498 if(result == CURLE_OK) {
499 CERT_CHAIN_PARA ChainPara;
500
501 memset(&ChainPara, 0, sizeof(ChainPara));
502 ChainPara.cbSize = sizeof(ChainPara);
503
504 if(!CertGetCertificateChain(cert_chain_engine,
505 pCertContextServer,
506 NULL,
507 pCertContextServer->hCertStore,
508 &ChainPara,
509 (data->set.ssl.no_revoke ? 0 :
510 CERT_CHAIN_REVOCATION_CHECK_CHAIN),
511 NULL,
512 &pChainContext)) {
513 char buffer[STRERROR_LEN];
514 failf(data, "schannel: CertGetCertificateChain failed: %s",
515 Curl_strerror(GetLastError(), buffer, sizeof(buffer)));
516 pChainContext = NULL;
517 result = CURLE_PEER_FAILED_VERIFICATION;
518 }
519
520 if(result == CURLE_OK) {
521 CERT_SIMPLE_CHAIN *pSimpleChain = pChainContext->rgpChain[0];
522 DWORD dwTrustErrorMask = ~(DWORD)(CERT_TRUST_IS_NOT_TIME_NESTED);
523 dwTrustErrorMask &= pSimpleChain->TrustStatus.dwErrorStatus;
524 if(dwTrustErrorMask) {
525 if(dwTrustErrorMask & CERT_TRUST_IS_REVOKED)
526 failf(data, "schannel: CertGetCertificateChain trust error"
527 " CERT_TRUST_IS_REVOKED");
528 else if(dwTrustErrorMask & CERT_TRUST_IS_PARTIAL_CHAIN)
529 failf(data, "schannel: CertGetCertificateChain trust error"
530 " CERT_TRUST_IS_PARTIAL_CHAIN");
531 else if(dwTrustErrorMask & CERT_TRUST_IS_UNTRUSTED_ROOT)
532 failf(data, "schannel: CertGetCertificateChain trust error"
533 " CERT_TRUST_IS_UNTRUSTED_ROOT");
534 else if(dwTrustErrorMask & CERT_TRUST_IS_NOT_TIME_VALID)
535 failf(data, "schannel: CertGetCertificateChain trust error"
536 " CERT_TRUST_IS_NOT_TIME_VALID");
537 else if(dwTrustErrorMask & CERT_TRUST_REVOCATION_STATUS_UNKNOWN)
538 failf(data, "schannel: CertGetCertificateChain trust error"
539 " CERT_TRUST_REVOCATION_STATUS_UNKNOWN");
540 else
541 failf(data, "schannel: CertGetCertificateChain error mask: 0x%08x",
542 dwTrustErrorMask);
543 result = CURLE_PEER_FAILED_VERIFICATION;
544 }
545 }
546 }
547
548 if(result == CURLE_OK) {
549 if(SSL_CONN_CONFIG(verifyhost)) {
550 result = verify_host(conn->data, pCertContextServer, conn_hostname);
551 }
552 }
553
554 if(cert_chain_engine) {
555 CertFreeCertificateChainEngine(cert_chain_engine);
556 }
557
558 if(trust_store) {
559 CertCloseStore(trust_store, 0);
560 }
561
562 if(pChainContext)
563 CertFreeCertificateChain(pChainContext);
564
565 if(pCertContextServer)
566 CertFreeCertificateContext(pCertContextServer);
567
568 return result;
569 }
570
571 #endif /* HAS_MANUAL_VERIFY_API */
572 #endif /* USE_SCHANNEL */
573