1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 2014 - 2016, Steve Holme, <steve_holme@hotmail.com>.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.haxx.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 * RFC4752 The Kerberos V5 ("GSSAPI") SASL Mechanism
22 *
23 ***************************************************************************/
24
25 #include "curl_setup.h"
26
27 #if defined(USE_WINDOWS_SSPI) && defined(USE_KERBEROS5)
28
29 #include <curl/curl.h>
30
31 #include "vauth/vauth.h"
32 #include "urldata.h"
33 #include "curl_base64.h"
34 #include "warnless.h"
35 #include "curl_multibyte.h"
36 #include "sendf.h"
37
38 /* The last #include files should be: */
39 #include "curl_memory.h"
40 #include "memdebug.h"
41
42 /*
43 * Curl_auth_create_gssapi_user_message()
44 *
45 * This is used to generate an already encoded GSSAPI (Kerberos V5) user token
46 * message ready for sending to the recipient.
47 *
48 * Parameters:
49 *
50 * data [in] - The session handle.
51 * userp [in] - The user name in the format User or Domain\User.
52 * passdwp [in] - The user's password.
53 * service [in] - The service type such as http, smtp, pop or imap.
54 * host [in] - The host name.
55 * mutual_auth [in] - Flag specifing whether or not mutual authentication
56 * is enabled.
57 * chlg64 [in] - The optional base64 encoded challenge message.
58 * krb5 [in/out] - The Kerberos 5 data struct being used and modified.
59 * outptr [in/out] - The address where a pointer to newly allocated memory
60 * holding the result will be stored upon completion.
61 * outlen [out] - The length of the output message.
62 *
63 * Returns CURLE_OK on success.
64 */
Curl_auth_create_gssapi_user_message(struct Curl_easy * data,const char * userp,const char * passwdp,const char * service,const char * host,const bool mutual_auth,const char * chlg64,struct kerberos5data * krb5,char ** outptr,size_t * outlen)65 CURLcode Curl_auth_create_gssapi_user_message(struct Curl_easy *data,
66 const char *userp,
67 const char *passwdp,
68 const char *service,
69 const char *host,
70 const bool mutual_auth,
71 const char *chlg64,
72 struct kerberos5data *krb5,
73 char **outptr, size_t *outlen)
74 {
75 CURLcode result = CURLE_OK;
76 size_t chlglen = 0;
77 unsigned char *chlg = NULL;
78 CtxtHandle context;
79 PSecPkgInfo SecurityPackage;
80 SecBuffer chlg_buf;
81 SecBuffer resp_buf;
82 SecBufferDesc chlg_desc;
83 SecBufferDesc resp_desc;
84 SECURITY_STATUS status;
85 unsigned long attrs;
86 TimeStamp expiry; /* For Windows 9x compatibility of SSPI calls */
87
88 if(!krb5->spn) {
89 /* Generate our SPN */
90 krb5->spn = Curl_auth_build_spn(service, host, NULL);
91 if(!krb5->spn)
92 return CURLE_OUT_OF_MEMORY;
93 }
94
95 if(!krb5->output_token) {
96 /* Query the security package for Kerberos */
97 status = s_pSecFn->QuerySecurityPackageInfo((TCHAR *)
98 TEXT(SP_NAME_KERBEROS),
99 &SecurityPackage);
100 if(status != SEC_E_OK) {
101 return CURLE_NOT_BUILT_IN;
102 }
103
104 krb5->token_max = SecurityPackage->cbMaxToken;
105
106 /* Release the package buffer as it is not required anymore */
107 s_pSecFn->FreeContextBuffer(SecurityPackage);
108
109 /* Allocate our response buffer */
110 krb5->output_token = malloc(krb5->token_max);
111 if(!krb5->output_token)
112 return CURLE_OUT_OF_MEMORY;
113 }
114
115 if(!krb5->credentials) {
116 /* Do we have credientials to use or are we using single sign-on? */
117 if(userp && *userp) {
118 /* Populate our identity structure */
119 result = Curl_create_sspi_identity(userp, passwdp, &krb5->identity);
120 if(result)
121 return result;
122
123 /* Allow proper cleanup of the identity structure */
124 krb5->p_identity = &krb5->identity;
125 }
126 else
127 /* Use the current Windows user */
128 krb5->p_identity = NULL;
129
130 /* Allocate our credentials handle */
131 krb5->credentials = malloc(sizeof(CredHandle));
132 if(!krb5->credentials)
133 return CURLE_OUT_OF_MEMORY;
134
135 memset(krb5->credentials, 0, sizeof(CredHandle));
136
137 /* Acquire our credentials handle */
138 status = s_pSecFn->AcquireCredentialsHandle(NULL,
139 (TCHAR *)
140 TEXT(SP_NAME_KERBEROS),
141 SECPKG_CRED_OUTBOUND, NULL,
142 krb5->p_identity, NULL, NULL,
143 krb5->credentials, &expiry);
144 if(status != SEC_E_OK)
145 return CURLE_LOGIN_DENIED;
146
147 /* Allocate our new context handle */
148 krb5->context = malloc(sizeof(CtxtHandle));
149 if(!krb5->context)
150 return CURLE_OUT_OF_MEMORY;
151
152 memset(krb5->context, 0, sizeof(CtxtHandle));
153 }
154
155 if(chlg64 && *chlg64) {
156 /* Decode the base-64 encoded challenge message */
157 if(*chlg64 != '=') {
158 result = Curl_base64_decode(chlg64, &chlg, &chlglen);
159 if(result)
160 return result;
161 }
162
163 /* Ensure we have a valid challenge message */
164 if(!chlg) {
165 infof(data, "GSSAPI handshake failure (empty challenge message)\n");
166
167 return CURLE_BAD_CONTENT_ENCODING;
168 }
169
170 /* Setup the challenge "input" security buffer */
171 chlg_desc.ulVersion = SECBUFFER_VERSION;
172 chlg_desc.cBuffers = 1;
173 chlg_desc.pBuffers = &chlg_buf;
174 chlg_buf.BufferType = SECBUFFER_TOKEN;
175 chlg_buf.pvBuffer = chlg;
176 chlg_buf.cbBuffer = curlx_uztoul(chlglen);
177 }
178
179 /* Setup the response "output" security buffer */
180 resp_desc.ulVersion = SECBUFFER_VERSION;
181 resp_desc.cBuffers = 1;
182 resp_desc.pBuffers = &resp_buf;
183 resp_buf.BufferType = SECBUFFER_TOKEN;
184 resp_buf.pvBuffer = krb5->output_token;
185 resp_buf.cbBuffer = curlx_uztoul(krb5->token_max);
186
187 /* Generate our challenge-response message */
188 status = s_pSecFn->InitializeSecurityContext(krb5->credentials,
189 chlg ? krb5->context : NULL,
190 krb5->spn,
191 (mutual_auth ?
192 ISC_REQ_MUTUAL_AUTH : 0),
193 0, SECURITY_NATIVE_DREP,
194 chlg ? &chlg_desc : NULL, 0,
195 &context,
196 &resp_desc, &attrs,
197 &expiry);
198
199 /* Free the decoded challenge as it is not required anymore */
200 free(chlg);
201
202 if(status != SEC_E_OK && status != SEC_I_CONTINUE_NEEDED) {
203 return CURLE_RECV_ERROR;
204 }
205
206 if(memcmp(&context, krb5->context, sizeof(context))) {
207 s_pSecFn->DeleteSecurityContext(krb5->context);
208
209 memcpy(krb5->context, &context, sizeof(context));
210 }
211
212 if(resp_buf.cbBuffer) {
213 /* Base64 encode the response */
214 result = Curl_base64_encode(data, (char *) resp_buf.pvBuffer,
215 resp_buf.cbBuffer, outptr, outlen);
216 }
217 else if(mutual_auth) {
218 *outptr = strdup("");
219 if(!*outptr)
220 result = CURLE_OUT_OF_MEMORY;
221 }
222
223 return result;
224 }
225
226 /*
227 * Curl_auth_create_gssapi_security_message()
228 *
229 * This is used to generate an already encoded GSSAPI (Kerberos V5) security
230 * token message ready for sending to the recipient.
231 *
232 * Parameters:
233 *
234 * data [in] - The session handle.
235 * chlg64 [in] - The optional base64 encoded challenge message.
236 * krb5 [in/out] - The Kerberos 5 data struct being used and modified.
237 * outptr [in/out] - The address where a pointer to newly allocated memory
238 * holding the result will be stored upon completion.
239 * outlen [out] - The length of the output message.
240 *
241 * Returns CURLE_OK on success.
242 */
Curl_auth_create_gssapi_security_message(struct Curl_easy * data,const char * chlg64,struct kerberos5data * krb5,char ** outptr,size_t * outlen)243 CURLcode Curl_auth_create_gssapi_security_message(struct Curl_easy *data,
244 const char *chlg64,
245 struct kerberos5data *krb5,
246 char **outptr,
247 size_t *outlen)
248 {
249 CURLcode result = CURLE_OK;
250 size_t offset = 0;
251 size_t chlglen = 0;
252 size_t messagelen = 0;
253 size_t appdatalen = 0;
254 unsigned char *chlg = NULL;
255 unsigned char *trailer = NULL;
256 unsigned char *message = NULL;
257 unsigned char *padding = NULL;
258 unsigned char *appdata = NULL;
259 SecBuffer input_buf[2];
260 SecBuffer wrap_buf[3];
261 SecBufferDesc input_desc;
262 SecBufferDesc wrap_desc;
263 unsigned long indata = 0;
264 unsigned long outdata = 0;
265 unsigned long qop = 0;
266 unsigned long sec_layer = 0;
267 unsigned long max_size = 0;
268 SecPkgContext_Sizes sizes;
269 SecPkgCredentials_Names names;
270 SECURITY_STATUS status;
271 char *user_name;
272
273 /* Decode the base-64 encoded input message */
274 if(strlen(chlg64) && *chlg64 != '=') {
275 result = Curl_base64_decode(chlg64, &chlg, &chlglen);
276 if(result)
277 return result;
278 }
279
280 /* Ensure we have a valid challenge message */
281 if(!chlg) {
282 infof(data, "GSSAPI handshake failure (empty security message)\n");
283
284 return CURLE_BAD_CONTENT_ENCODING;
285 }
286
287 /* Get our response size information */
288 status = s_pSecFn->QueryContextAttributes(krb5->context,
289 SECPKG_ATTR_SIZES,
290 &sizes);
291 if(status != SEC_E_OK) {
292 free(chlg);
293
294 return CURLE_OUT_OF_MEMORY;
295 }
296
297 /* Get the fully qualified username back from the context */
298 status = s_pSecFn->QueryCredentialsAttributes(krb5->credentials,
299 SECPKG_CRED_ATTR_NAMES,
300 &names);
301 if(status != SEC_E_OK) {
302 free(chlg);
303
304 return CURLE_RECV_ERROR;
305 }
306
307 /* Setup the "input" security buffer */
308 input_desc.ulVersion = SECBUFFER_VERSION;
309 input_desc.cBuffers = 2;
310 input_desc.pBuffers = input_buf;
311 input_buf[0].BufferType = SECBUFFER_STREAM;
312 input_buf[0].pvBuffer = chlg;
313 input_buf[0].cbBuffer = curlx_uztoul(chlglen);
314 input_buf[1].BufferType = SECBUFFER_DATA;
315 input_buf[1].pvBuffer = NULL;
316 input_buf[1].cbBuffer = 0;
317
318 /* Decrypt the inbound challenge and obtain the qop */
319 status = s_pSecFn->DecryptMessage(krb5->context, &input_desc, 0, &qop);
320 if(status != SEC_E_OK) {
321 infof(data, "GSSAPI handshake failure (empty security message)\n");
322
323 free(chlg);
324
325 return CURLE_BAD_CONTENT_ENCODING;
326 }
327
328 /* Not 4 octets long so fail as per RFC4752 Section 3.1 */
329 if(input_buf[1].cbBuffer != 4) {
330 infof(data, "GSSAPI handshake failure (invalid security data)\n");
331
332 free(chlg);
333
334 return CURLE_BAD_CONTENT_ENCODING;
335 }
336
337 /* Copy the data out and free the challenge as it is not required anymore */
338 memcpy(&indata, input_buf[1].pvBuffer, 4);
339 s_pSecFn->FreeContextBuffer(input_buf[1].pvBuffer);
340 free(chlg);
341
342 /* Extract the security layer */
343 sec_layer = indata & 0x000000FF;
344 if(!(sec_layer & KERB_WRAP_NO_ENCRYPT)) {
345 infof(data, "GSSAPI handshake failure (invalid security layer)\n");
346
347 return CURLE_BAD_CONTENT_ENCODING;
348 }
349
350 /* Extract the maximum message size the server can receive */
351 max_size = ntohl(indata & 0xFFFFFF00);
352 if(max_size > 0) {
353 /* The server has told us it supports a maximum receive buffer, however, as
354 we don't require one unless we are encrypting data, we tell the server
355 our receive buffer is zero. */
356 max_size = 0;
357 }
358
359 /* Allocate the trailer */
360 trailer = malloc(sizes.cbSecurityTrailer);
361 if(!trailer)
362 return CURLE_OUT_OF_MEMORY;
363
364 /* Convert the user name to UTF8 when operating with Unicode */
365 user_name = Curl_convert_tchar_to_UTF8(names.sUserName);
366 if(!user_name) {
367 free(trailer);
368
369 return CURLE_OUT_OF_MEMORY;
370 }
371
372 /* Allocate our message */
373 messagelen = sizeof(outdata) + strlen(user_name) + 1;
374 message = malloc(messagelen);
375 if(!message) {
376 free(trailer);
377 Curl_unicodefree(user_name);
378
379 return CURLE_OUT_OF_MEMORY;
380 }
381
382 /* Populate the message with the security layer, client supported receive
383 message size and authorization identity including the 0x00 based
384 terminator. Note: Despite RFC4752 Section 3.1 stating "The authorization
385 identity is not terminated with the zero-valued (%x00) octet." it seems
386 necessary to include it. */
387 outdata = htonl(max_size) | sec_layer;
388 memcpy(message, &outdata, sizeof(outdata));
389 strcpy((char *) message + sizeof(outdata), user_name);
390 Curl_unicodefree(user_name);
391
392 /* Allocate the padding */
393 padding = malloc(sizes.cbBlockSize);
394 if(!padding) {
395 free(message);
396 free(trailer);
397
398 return CURLE_OUT_OF_MEMORY;
399 }
400
401 /* Setup the "authentication data" security buffer */
402 wrap_desc.ulVersion = SECBUFFER_VERSION;
403 wrap_desc.cBuffers = 3;
404 wrap_desc.pBuffers = wrap_buf;
405 wrap_buf[0].BufferType = SECBUFFER_TOKEN;
406 wrap_buf[0].pvBuffer = trailer;
407 wrap_buf[0].cbBuffer = sizes.cbSecurityTrailer;
408 wrap_buf[1].BufferType = SECBUFFER_DATA;
409 wrap_buf[1].pvBuffer = message;
410 wrap_buf[1].cbBuffer = curlx_uztoul(messagelen);
411 wrap_buf[2].BufferType = SECBUFFER_PADDING;
412 wrap_buf[2].pvBuffer = padding;
413 wrap_buf[2].cbBuffer = sizes.cbBlockSize;
414
415 /* Encrypt the data */
416 status = s_pSecFn->EncryptMessage(krb5->context, KERB_WRAP_NO_ENCRYPT,
417 &wrap_desc, 0);
418 if(status != SEC_E_OK) {
419 free(padding);
420 free(message);
421 free(trailer);
422
423 return CURLE_OUT_OF_MEMORY;
424 }
425
426 /* Allocate the encryption (wrap) buffer */
427 appdatalen = wrap_buf[0].cbBuffer + wrap_buf[1].cbBuffer +
428 wrap_buf[2].cbBuffer;
429 appdata = malloc(appdatalen);
430 if(!appdata) {
431 free(padding);
432 free(message);
433 free(trailer);
434
435 return CURLE_OUT_OF_MEMORY;
436 }
437
438 /* Populate the encryption buffer */
439 memcpy(appdata, wrap_buf[0].pvBuffer, wrap_buf[0].cbBuffer);
440 offset += wrap_buf[0].cbBuffer;
441 memcpy(appdata + offset, wrap_buf[1].pvBuffer, wrap_buf[1].cbBuffer);
442 offset += wrap_buf[1].cbBuffer;
443 memcpy(appdata + offset, wrap_buf[2].pvBuffer, wrap_buf[2].cbBuffer);
444
445 /* Base64 encode the response */
446 result = Curl_base64_encode(data, (char *) appdata, appdatalen, outptr,
447 outlen);
448
449 /* Free all of our local buffers */
450 free(appdata);
451 free(padding);
452 free(message);
453 free(trailer);
454
455 return result;
456 }
457
458 /*
459 * Curl_auth_gssapi_cleanup()
460 *
461 * This is used to clean up the GSSAPI (Kerberos V5) specific data.
462 *
463 * Parameters:
464 *
465 * krb5 [in/out] - The Kerberos 5 data struct being cleaned up.
466 *
467 */
Curl_auth_gssapi_cleanup(struct kerberos5data * krb5)468 void Curl_auth_gssapi_cleanup(struct kerberos5data *krb5)
469 {
470 /* Free our security context */
471 if(krb5->context) {
472 s_pSecFn->DeleteSecurityContext(krb5->context);
473 free(krb5->context);
474 krb5->context = NULL;
475 }
476
477 /* Free our credentials handle */
478 if(krb5->credentials) {
479 s_pSecFn->FreeCredentialsHandle(krb5->credentials);
480 free(krb5->credentials);
481 krb5->credentials = NULL;
482 }
483
484 /* Free our identity */
485 Curl_sspi_free_identity(krb5->p_identity);
486 krb5->p_identity = NULL;
487
488 /* Free the SPN and output token */
489 Curl_safefree(krb5->spn);
490 Curl_safefree(krb5->output_token);
491
492 /* Reset any variables */
493 krb5->token_max = 0;
494 }
495
496 #endif /* USE_WINDOWS_SSPI && USE_KERBEROS5*/
497