1 /*
2 * tsig.c
3 *
4 * contains the functions needed for TSIG [RFC2845]
5 *
6 * (c) 2005-2006 NLnet Labs
7 * See the file LICENSE for the license
8 */
9
10 #include <ldns/config.h>
11
12 #include <ldns/ldns.h>
13
14 #include <strings.h>
15
16 #ifdef HAVE_SSL
17 #include <openssl/hmac.h>
18 #include <openssl/md5.h>
19 #endif /* HAVE_SSL */
20
21 char *
ldns_tsig_algorithm(ldns_tsig_credentials * tc)22 ldns_tsig_algorithm(ldns_tsig_credentials *tc)
23 {
24 return tc->algorithm;
25 }
26
27 char *
ldns_tsig_keyname(ldns_tsig_credentials * tc)28 ldns_tsig_keyname(ldns_tsig_credentials *tc)
29 {
30 return tc->keyname;
31 }
32
33 char *
ldns_tsig_keydata(ldns_tsig_credentials * tc)34 ldns_tsig_keydata(ldns_tsig_credentials *tc)
35 {
36 return tc->keydata;
37 }
38
39 char *
ldns_tsig_keyname_clone(ldns_tsig_credentials * tc)40 ldns_tsig_keyname_clone(ldns_tsig_credentials *tc)
41 {
42 return strdup(tc->keyname);
43 }
44
45 char *
ldns_tsig_keydata_clone(ldns_tsig_credentials * tc)46 ldns_tsig_keydata_clone(ldns_tsig_credentials *tc)
47 {
48 return strdup(tc->keydata);
49 }
50
51 /*
52 * Makes an exact copy of the wire, but with the tsig rr removed
53 */
54 static uint8_t *
ldns_tsig_prepare_pkt_wire(uint8_t * wire,size_t wire_len,size_t * result_len)55 ldns_tsig_prepare_pkt_wire(uint8_t *wire, size_t wire_len, size_t *result_len)
56 {
57 uint8_t *wire2 = NULL;
58 uint16_t qd_count;
59 uint16_t an_count;
60 uint16_t ns_count;
61 uint16_t ar_count;
62 ldns_rr *rr;
63
64 size_t pos;
65 uint16_t i;
66
67 ldns_status status;
68
69 if(wire_len < LDNS_HEADER_SIZE) {
70 return NULL;
71 }
72 /* fake parse the wire */
73 qd_count = LDNS_QDCOUNT(wire);
74 an_count = LDNS_ANCOUNT(wire);
75 ns_count = LDNS_NSCOUNT(wire);
76 ar_count = LDNS_ARCOUNT(wire);
77
78 if (ar_count > 0) {
79 ar_count--;
80 } else {
81 return NULL;
82 }
83
84 pos = LDNS_HEADER_SIZE;
85
86 for (i = 0; i < qd_count; i++) {
87 status = ldns_wire2rr(&rr, wire, wire_len, &pos, LDNS_SECTION_QUESTION);
88 if (status != LDNS_STATUS_OK) {
89 return NULL;
90 }
91 ldns_rr_free(rr);
92 }
93
94 for (i = 0; i < an_count; i++) {
95 status = ldns_wire2rr(&rr, wire, wire_len, &pos, LDNS_SECTION_ANSWER);
96 if (status != LDNS_STATUS_OK) {
97 return NULL;
98 }
99 ldns_rr_free(rr);
100 }
101
102 for (i = 0; i < ns_count; i++) {
103 status = ldns_wire2rr(&rr, wire, wire_len, &pos, LDNS_SECTION_AUTHORITY);
104 if (status != LDNS_STATUS_OK) {
105 return NULL;
106 }
107 ldns_rr_free(rr);
108 }
109
110 for (i = 0; i < ar_count; i++) {
111 status = ldns_wire2rr(&rr, wire, wire_len, &pos,
112 LDNS_SECTION_ADDITIONAL);
113 if (status != LDNS_STATUS_OK) {
114 return NULL;
115 }
116 ldns_rr_free(rr);
117 }
118
119 *result_len = pos;
120 wire2 = LDNS_XMALLOC(uint8_t, *result_len);
121 if(!wire2) {
122 return NULL;
123 }
124 memcpy(wire2, wire, *result_len);
125
126 ldns_write_uint16(wire2 + LDNS_ARCOUNT_OFF, ar_count);
127
128 return wire2;
129 }
130
131 #ifdef HAVE_SSL
132 static const EVP_MD *
ldns_digest_function(char * name)133 ldns_digest_function(char *name)
134 {
135 /* these are the mandatory algorithms from RFC4635 */
136 /* The optional algorithms are not yet implemented */
137 if (strcasecmp(name, "hmac-sha256.") == 0) {
138 #ifdef HAVE_EVP_SHA256
139 return EVP_sha256();
140 #else
141 return NULL;
142 #endif
143 } else if (strcasecmp(name, "hmac-sha1.") == 0) {
144 return EVP_sha1();
145 } else if (strcasecmp(name, "hmac-md5.sig-alg.reg.int.") == 0) {
146 return EVP_md5();
147 } else {
148 return NULL;
149 }
150 }
151 #endif
152
153 #ifdef HAVE_SSL
154 static ldns_status
ldns_tsig_mac_new(ldns_rdf ** tsig_mac,uint8_t * pkt_wire,size_t pkt_wire_size,const char * key_data,ldns_rdf * key_name_rdf,ldns_rdf * fudge_rdf,ldns_rdf * algorithm_rdf,ldns_rdf * time_signed_rdf,ldns_rdf * error_rdf,ldns_rdf * other_data_rdf,ldns_rdf * orig_mac_rdf,int tsig_timers_only)155 ldns_tsig_mac_new(ldns_rdf **tsig_mac, uint8_t *pkt_wire, size_t pkt_wire_size,
156 const char *key_data, ldns_rdf *key_name_rdf, ldns_rdf *fudge_rdf,
157 ldns_rdf *algorithm_rdf, ldns_rdf *time_signed_rdf, ldns_rdf *error_rdf,
158 ldns_rdf *other_data_rdf, ldns_rdf *orig_mac_rdf, int tsig_timers_only)
159 {
160 ldns_status status;
161 char *wireformat;
162 int wiresize;
163 unsigned char *mac_bytes = NULL;
164 unsigned char *key_bytes = NULL;
165 int key_size;
166 const EVP_MD *digester;
167 char *algorithm_name = NULL;
168 unsigned int md_len = EVP_MAX_MD_SIZE;
169 ldns_rdf *result = NULL;
170 ldns_buffer *data_buffer = NULL;
171 ldns_rdf *canonical_key_name_rdf = NULL;
172 ldns_rdf *canonical_algorithm_rdf = NULL;
173
174 if (key_name_rdf == NULL || algorithm_rdf == NULL) {
175 return LDNS_STATUS_NULL;
176 }
177 canonical_key_name_rdf = ldns_rdf_clone(key_name_rdf);
178 if (canonical_key_name_rdf == NULL) {
179 return LDNS_STATUS_MEM_ERR;
180 }
181 canonical_algorithm_rdf = ldns_rdf_clone(algorithm_rdf);
182 if (canonical_algorithm_rdf == NULL) {
183 ldns_rdf_deep_free(canonical_key_name_rdf);
184 return LDNS_STATUS_MEM_ERR;
185 }
186 /*
187 * prepare the digestable information
188 */
189 data_buffer = ldns_buffer_new(LDNS_MAX_PACKETLEN);
190 if (!data_buffer) {
191 status = LDNS_STATUS_MEM_ERR;
192 goto clean;
193 }
194 /* if orig_mac is not NULL, add it too */
195 if (orig_mac_rdf) {
196 (void) ldns_rdf2buffer_wire(data_buffer, orig_mac_rdf);
197 }
198 ldns_buffer_write(data_buffer, pkt_wire, pkt_wire_size);
199 if (!tsig_timers_only) {
200 ldns_dname2canonical(canonical_key_name_rdf);
201 (void)ldns_rdf2buffer_wire(data_buffer,
202 canonical_key_name_rdf);
203 ldns_buffer_write_u16(data_buffer, LDNS_RR_CLASS_ANY);
204 ldns_buffer_write_u32(data_buffer, 0);
205 ldns_dname2canonical(canonical_algorithm_rdf);
206 (void)ldns_rdf2buffer_wire(data_buffer,
207 canonical_algorithm_rdf);
208 }
209 (void)ldns_rdf2buffer_wire(data_buffer, time_signed_rdf);
210 (void)ldns_rdf2buffer_wire(data_buffer, fudge_rdf);
211 if (!tsig_timers_only) {
212 (void)ldns_rdf2buffer_wire(data_buffer, error_rdf);
213 (void)ldns_rdf2buffer_wire(data_buffer, other_data_rdf);
214 }
215
216 wireformat = (char *) data_buffer->_data;
217 wiresize = (int) ldns_buffer_position(data_buffer);
218
219 algorithm_name = ldns_rdf2str(algorithm_rdf);
220 if(!algorithm_name) {
221 status = LDNS_STATUS_MEM_ERR;
222 goto clean;
223 }
224
225 /* prepare the key */
226 key_bytes = LDNS_XMALLOC(unsigned char,
227 ldns_b64_pton_calculate_size(strlen(key_data)));
228 if(!key_bytes) {
229 status = LDNS_STATUS_MEM_ERR;
230 goto clean;
231 }
232 key_size = ldns_b64_pton(key_data, key_bytes,
233 ldns_b64_pton_calculate_size(strlen(key_data)));
234 if (key_size < 0) {
235 status = LDNS_STATUS_INVALID_B64;
236 goto clean;
237 }
238 /* hmac it */
239 /* 2 spare bytes for the length */
240 mac_bytes = LDNS_XMALLOC(unsigned char, md_len+2);
241 if(!mac_bytes) {
242 status = LDNS_STATUS_MEM_ERR;
243 goto clean;
244 }
245 memset(mac_bytes, 0, md_len+2);
246
247 digester = ldns_digest_function(algorithm_name);
248
249 if (digester) {
250 (void) HMAC(digester, key_bytes, key_size, (void *)wireformat,
251 (size_t) wiresize, mac_bytes + 2, &md_len);
252
253 ldns_write_uint16(mac_bytes, md_len);
254 result = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_INT16_DATA, md_len + 2,
255 mac_bytes);
256 } else {
257 status = LDNS_STATUS_CRYPTO_UNKNOWN_ALGO;
258 goto clean;
259 }
260 *tsig_mac = result;
261 status = LDNS_STATUS_OK;
262 clean:
263 LDNS_FREE(mac_bytes);
264 LDNS_FREE(key_bytes);
265 LDNS_FREE(algorithm_name);
266 ldns_buffer_free(data_buffer);
267 ldns_rdf_deep_free(canonical_algorithm_rdf);
268 ldns_rdf_deep_free(canonical_key_name_rdf);
269 return status;
270 }
271 #endif /* HAVE_SSL */
272
273
274 #ifdef HAVE_SSL
275 bool
ldns_pkt_tsig_verify(ldns_pkt * pkt,uint8_t * wire,size_t wirelen,const char * key_name,const char * key_data,ldns_rdf * orig_mac_rdf)276 ldns_pkt_tsig_verify(ldns_pkt *pkt, uint8_t *wire, size_t wirelen, const char *key_name,
277 const char *key_data, ldns_rdf *orig_mac_rdf)
278 {
279 return ldns_pkt_tsig_verify_next(pkt, wire, wirelen, key_name, key_data, orig_mac_rdf, 0);
280 }
281
282 bool
ldns_pkt_tsig_verify_next(ldns_pkt * pkt,uint8_t * wire,size_t wirelen,const char * key_name,const char * key_data,ldns_rdf * orig_mac_rdf,int tsig_timers_only)283 ldns_pkt_tsig_verify_next(ldns_pkt *pkt, uint8_t *wire, size_t wirelen, const char* key_name,
284 const char *key_data, ldns_rdf *orig_mac_rdf, int tsig_timers_only)
285 {
286 ldns_rdf *fudge_rdf;
287 ldns_rdf *algorithm_rdf;
288 ldns_rdf *time_signed_rdf;
289 ldns_rdf *orig_id_rdf;
290 ldns_rdf *error_rdf;
291 ldns_rdf *other_data_rdf;
292 ldns_rdf *pkt_mac_rdf;
293 ldns_rdf *my_mac_rdf;
294 ldns_rdf *key_name_rdf = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, key_name);
295 uint16_t pkt_id, orig_pkt_id;
296 ldns_status status;
297
298 uint8_t *prepared_wire = NULL;
299 size_t prepared_wire_size = 0;
300
301 ldns_rr *orig_tsig = ldns_pkt_tsig(pkt);
302
303 if (!orig_tsig || ldns_rr_rd_count(orig_tsig) <= 6) {
304 ldns_rdf_deep_free(key_name_rdf);
305 return false;
306 }
307 algorithm_rdf = ldns_rr_rdf(orig_tsig, 0);
308 time_signed_rdf = ldns_rr_rdf(orig_tsig, 1);
309 fudge_rdf = ldns_rr_rdf(orig_tsig, 2);
310 pkt_mac_rdf = ldns_rr_rdf(orig_tsig, 3);
311 orig_id_rdf = ldns_rr_rdf(orig_tsig, 4);
312 error_rdf = ldns_rr_rdf(orig_tsig, 5);
313 other_data_rdf = ldns_rr_rdf(orig_tsig, 6);
314
315 /* remove temporarily */
316 ldns_pkt_set_tsig(pkt, NULL);
317 /* temporarily change the id to the original id */
318 pkt_id = ldns_pkt_id(pkt);
319 orig_pkt_id = ldns_rdf2native_int16(orig_id_rdf);
320 ldns_pkt_set_id(pkt, orig_pkt_id);
321
322 prepared_wire = ldns_tsig_prepare_pkt_wire(wire, wirelen, &prepared_wire_size);
323
324 status = ldns_tsig_mac_new(&my_mac_rdf, prepared_wire, prepared_wire_size,
325 key_data, key_name_rdf, fudge_rdf, algorithm_rdf,
326 time_signed_rdf, error_rdf, other_data_rdf, orig_mac_rdf, tsig_timers_only);
327
328 LDNS_FREE(prepared_wire);
329
330 if (status != LDNS_STATUS_OK) {
331 ldns_rdf_deep_free(key_name_rdf);
332 return false;
333 }
334 /* Put back the values */
335 ldns_pkt_set_tsig(pkt, orig_tsig);
336 ldns_pkt_set_id(pkt, pkt_id);
337
338 ldns_rdf_deep_free(key_name_rdf);
339
340 if (ldns_rdf_compare(pkt_mac_rdf, my_mac_rdf) == 0) {
341 ldns_rdf_deep_free(my_mac_rdf);
342 return true;
343 } else {
344 ldns_rdf_deep_free(my_mac_rdf);
345 return false;
346 }
347 }
348 #endif /* HAVE_SSL */
349
350 #ifdef HAVE_SSL
351 ldns_status
ldns_pkt_tsig_sign(ldns_pkt * pkt,const char * key_name,const char * key_data,uint16_t fudge,const char * algorithm_name,ldns_rdf * query_mac)352 ldns_pkt_tsig_sign(ldns_pkt *pkt, const char *key_name, const char *key_data,
353 uint16_t fudge, const char *algorithm_name, ldns_rdf *query_mac)
354 {
355 return ldns_pkt_tsig_sign_next(pkt, key_name, key_data, fudge, algorithm_name, query_mac, 0);
356 }
357
358 ldns_status
ldns_pkt_tsig_sign_next(ldns_pkt * pkt,const char * key_name,const char * key_data,uint16_t fudge,const char * algorithm_name,ldns_rdf * query_mac,int tsig_timers_only)359 ldns_pkt_tsig_sign_next(ldns_pkt *pkt, const char *key_name, const char *key_data,
360 uint16_t fudge, const char *algorithm_name, ldns_rdf *query_mac, int tsig_timers_only)
361 {
362 ldns_rr *tsig_rr;
363 ldns_rdf *key_name_rdf = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, key_name);
364 ldns_rdf *fudge_rdf = NULL;
365 ldns_rdf *orig_id_rdf = NULL;
366 ldns_rdf *algorithm_rdf;
367 ldns_rdf *error_rdf = NULL;
368 ldns_rdf *mac_rdf = NULL;
369 ldns_rdf *other_data_rdf = NULL;
370
371 ldns_status status = LDNS_STATUS_OK;
372
373 uint8_t *pkt_wire = NULL;
374 size_t pkt_wire_len;
375
376 struct timeval tv_time_signed;
377 uint8_t *time_signed = NULL;
378 ldns_rdf *time_signed_rdf = NULL;
379
380 algorithm_rdf = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, algorithm_name);
381 if(!key_name_rdf || !algorithm_rdf) {
382 status = LDNS_STATUS_MEM_ERR;
383 goto clean;
384 }
385
386 /* eww don't have create tsigtime rdf yet :( */
387 /* bleh :p */
388 if (gettimeofday(&tv_time_signed, NULL) == 0) {
389 time_signed = LDNS_XMALLOC(uint8_t, 6);
390 if(!time_signed) {
391 status = LDNS_STATUS_MEM_ERR;
392 goto clean;
393 }
394 ldns_write_uint64_as_uint48(time_signed,
395 (uint64_t)tv_time_signed.tv_sec);
396 } else {
397 status = LDNS_STATUS_INTERNAL_ERR;
398 goto clean;
399 }
400
401 time_signed_rdf = ldns_rdf_new(LDNS_RDF_TYPE_TSIGTIME, 6, time_signed);
402 if(!time_signed_rdf) {
403 LDNS_FREE(time_signed);
404 status = LDNS_STATUS_MEM_ERR;
405 goto clean;
406 }
407
408 fudge_rdf = ldns_native2rdf_int16(LDNS_RDF_TYPE_INT16, fudge);
409
410 orig_id_rdf = ldns_native2rdf_int16(LDNS_RDF_TYPE_INT16, ldns_pkt_id(pkt));
411
412 error_rdf = ldns_native2rdf_int16(LDNS_RDF_TYPE_INT16, 0);
413
414 other_data_rdf = ldns_native2rdf_int16_data(0, NULL);
415
416 if(!fudge_rdf || !orig_id_rdf || !error_rdf || !other_data_rdf) {
417 status = LDNS_STATUS_MEM_ERR;
418 goto clean;
419 }
420
421 if (ldns_pkt2wire(&pkt_wire, pkt, &pkt_wire_len) != LDNS_STATUS_OK) {
422 status = LDNS_STATUS_ERR;
423 goto clean;
424 }
425
426 status = ldns_tsig_mac_new(&mac_rdf, pkt_wire, pkt_wire_len,
427 key_data, key_name_rdf, fudge_rdf, algorithm_rdf,
428 time_signed_rdf, error_rdf, other_data_rdf, query_mac, tsig_timers_only);
429
430 if (!mac_rdf) {
431 goto clean;
432 }
433
434 LDNS_FREE(pkt_wire);
435
436 /* Create the TSIG RR */
437 tsig_rr = ldns_rr_new();
438 if(!tsig_rr) {
439 status = LDNS_STATUS_MEM_ERR;
440 goto clean;
441 }
442 ldns_rr_set_owner(tsig_rr, key_name_rdf);
443 ldns_rr_set_class(tsig_rr, LDNS_RR_CLASS_ANY);
444 ldns_rr_set_type(tsig_rr, LDNS_RR_TYPE_TSIG);
445 ldns_rr_set_ttl(tsig_rr, 0);
446
447 ldns_rr_push_rdf(tsig_rr, algorithm_rdf);
448 ldns_rr_push_rdf(tsig_rr, time_signed_rdf);
449 ldns_rr_push_rdf(tsig_rr, fudge_rdf);
450 ldns_rr_push_rdf(tsig_rr, mac_rdf);
451 ldns_rr_push_rdf(tsig_rr, orig_id_rdf);
452 ldns_rr_push_rdf(tsig_rr, error_rdf);
453 ldns_rr_push_rdf(tsig_rr, other_data_rdf);
454
455 ldns_pkt_set_tsig(pkt, tsig_rr);
456
457 return status;
458
459 clean:
460 LDNS_FREE(pkt_wire);
461 ldns_rdf_free(key_name_rdf);
462 ldns_rdf_free(algorithm_rdf);
463 ldns_rdf_free(time_signed_rdf);
464 ldns_rdf_free(fudge_rdf);
465 ldns_rdf_free(orig_id_rdf);
466 ldns_rdf_free(error_rdf);
467 ldns_rdf_free(other_data_rdf);
468 return status;
469 }
470 #endif /* HAVE_SSL */
471