1 /* $NetBSD: ns_sign.c,v 1.1.1.2 2012/09/09 16:08:05 christos Exp $ */
2
3 /*
4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (c) 1999 by Internet Software Consortium, Inc.
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
17 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 #ifndef lint
21 static const char rcsid[] = "Id: ns_sign.c,v 1.6 2006/03/09 23:57:56 marka Exp ";
22 #endif
23
24 /* Import. */
25
26 #include "port_before.h"
27 #include "fd_setsize.h"
28
29 #include <sys/types.h>
30 #include <sys/param.h>
31
32 #include <netinet/in.h>
33 #include <arpa/nameser.h>
34 #include <arpa/inet.h>
35
36 #include <errno.h>
37 #include <netdb.h>
38 #include <resolv.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <time.h>
43 #include <unistd.h>
44
45 #include <isc/dst.h>
46 #include <isc/assertions.h>
47
48 #include "port_after.h"
49
50 #define BOUNDS_CHECK(ptr, count) \
51 do { \
52 if ((ptr) + (count) > eob) { \
53 errno = EMSGSIZE; \
54 return(NS_TSIG_ERROR_NO_SPACE); \
55 } \
56 } while (0)
57
58 /*%
59 * ns_sign
60 *
61 * Parameters:
62 *\li msg message to be sent
63 *\li msglen input - length of message
64 * output - length of signed message
65 *\li msgsize length of buffer containing message
66 *\li error value to put in the error field
67 *\li key tsig key used for signing
68 *\li querysig (response), the signature in the query
69 *\li querysiglen (response), the length of the signature in the query
70 *\li sig a buffer to hold the generated signature
71 *\li siglen input - length of signature buffer
72 * output - length of signature
73 *
74 * Errors:
75 *\li - bad input data (-1)
76 *\li - bad key / sign failed (-BADKEY)
77 *\li - not enough space (NS_TSIG_ERROR_NO_SPACE)
78 */
79 int
ns_sign(u_char * msg,int * msglen,int msgsize,int error,void * k,const u_char * querysig,int querysiglen,u_char * sig,int * siglen,time_t in_timesigned)80 ns_sign(u_char *msg, int *msglen, int msgsize, int error, void *k,
81 const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
82 time_t in_timesigned)
83 {
84 return(ns_sign2(msg, msglen, msgsize, error, k,
85 querysig, querysiglen, sig, siglen,
86 in_timesigned, NULL, NULL));
87 }
88
89 int
ns_sign2(u_char * msg,int * msglen,int msgsize,int error,void * k,const u_char * querysig,int querysiglen,u_char * sig,int * siglen,time_t in_timesigned,u_char ** dnptrs,u_char ** lastdnptr)90 ns_sign2(u_char *msg, int *msglen, int msgsize, int error, void *k,
91 const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
92 time_t in_timesigned, u_char **dnptrs, u_char **lastdnptr)
93 {
94 HEADER *hp = (HEADER *)msg;
95 DST_KEY *key = (DST_KEY *)k;
96 u_char *cp, *eob;
97 u_char *lenp;
98 u_char *alg;
99 int n;
100 time_t timesigned;
101 u_char name[NS_MAXCDNAME];
102
103 dst_init();
104 if (msg == NULL || msglen == NULL || sig == NULL || siglen == NULL)
105 return (-1);
106
107 cp = msg + *msglen;
108 eob = msg + msgsize;
109
110 /* Name. */
111 if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
112 n = ns_name_pton(key->dk_key_name, name, sizeof name);
113 if (n != -1)
114 n = ns_name_pack(name, cp, eob - cp,
115 (const u_char **)dnptrs,
116 (const u_char **)lastdnptr);
117
118 } else {
119 n = ns_name_pton("", name, sizeof name);
120 if (n != -1)
121 n = ns_name_pack(name, cp, eob - cp, NULL, NULL);
122 }
123 if (n < 0)
124 return (NS_TSIG_ERROR_NO_SPACE);
125 cp += n;
126
127 /* Type, class, ttl, length (not filled in yet). */
128 BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
129 PUTSHORT(ns_t_tsig, cp);
130 PUTSHORT(ns_c_any, cp);
131 PUTLONG(0, cp); /*%< TTL */
132 lenp = cp;
133 cp += 2;
134
135 /* Alg. */
136 if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
137 if (key->dk_alg != KEY_HMAC_MD5)
138 return (-ns_r_badkey);
139 n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
140 }
141 else
142 n = dn_comp("", cp, eob - cp, NULL, NULL);
143 if (n < 0)
144 return (NS_TSIG_ERROR_NO_SPACE);
145 alg = cp;
146 cp += n;
147
148 /* Time. */
149 BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
150 PUTSHORT(0, cp);
151 timesigned = time(NULL);
152 if (error != ns_r_badtime)
153 PUTLONG(timesigned, cp);
154 else
155 PUTLONG(in_timesigned, cp);
156 PUTSHORT(NS_TSIG_FUDGE, cp);
157
158 /* Compute the signature. */
159 if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
160 void *ctx;
161 u_char buf[NS_MAXCDNAME], *cp2;
162 int n;
163
164 dst_sign_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);
165
166 /* Digest the query signature, if this is a response. */
167 if (querysiglen > 0 && querysig != NULL) {
168 u_int16_t len_n = htons(querysiglen);
169 dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
170 (u_char *)&len_n, INT16SZ, NULL, 0);
171 dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
172 querysig, querysiglen, NULL, 0);
173 }
174
175 /* Digest the message. */
176 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, msg, *msglen,
177 NULL, 0);
178
179 /* Digest the key name. */
180 n = ns_name_ntol(name, buf, sizeof(buf));
181 INSIST(n > 0);
182 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
183
184 /* Digest the class and TTL. */
185 cp2 = buf;
186 PUTSHORT(ns_c_any, cp2);
187 PUTLONG(0, cp2);
188 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
189 NULL, 0);
190
191 /* Digest the algorithm. */
192 n = ns_name_ntol(alg, buf, sizeof(buf));
193 INSIST(n > 0);
194 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
195
196 /* Digest the time signed, fudge, error, and other data */
197 cp2 = buf;
198 PUTSHORT(0, cp2); /*%< Top 16 bits of time */
199 if (error != ns_r_badtime)
200 PUTLONG(timesigned, cp2);
201 else
202 PUTLONG(in_timesigned, cp2);
203 PUTSHORT(NS_TSIG_FUDGE, cp2);
204 PUTSHORT(error, cp2); /*%< Error */
205 if (error != ns_r_badtime)
206 PUTSHORT(0, cp2); /*%< Other data length */
207 else {
208 PUTSHORT(INT16SZ+INT32SZ, cp2); /*%< Other data length */
209 PUTSHORT(0, cp2); /*%< Top 16 bits of time */
210 PUTLONG(timesigned, cp2);
211 }
212 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
213 NULL, 0);
214
215 n = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
216 sig, *siglen);
217 if (n < 0)
218 return (-ns_r_badkey);
219 *siglen = n;
220 } else
221 *siglen = 0;
222
223 /* Add the signature. */
224 BOUNDS_CHECK(cp, INT16SZ + (*siglen));
225 PUTSHORT(*siglen, cp);
226 memcpy(cp, sig, *siglen);
227 cp += (*siglen);
228
229 /* The original message ID & error. */
230 BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
231 PUTSHORT(ntohs(hp->id), cp); /*%< already in network order */
232 PUTSHORT(error, cp);
233
234 /* Other data. */
235 BOUNDS_CHECK(cp, INT16SZ);
236 if (error != ns_r_badtime)
237 PUTSHORT(0, cp); /*%< Other data length */
238 else {
239 PUTSHORT(INT16SZ+INT32SZ, cp); /*%< Other data length */
240 BOUNDS_CHECK(cp, INT32SZ+INT16SZ);
241 PUTSHORT(0, cp); /*%< Top 16 bits of time */
242 PUTLONG(timesigned, cp);
243 }
244
245 /* Go back and fill in the length. */
246 PUTSHORT(cp - lenp - INT16SZ, lenp);
247
248 hp->arcount = htons(ntohs(hp->arcount) + 1);
249 *msglen = (cp - msg);
250 return (0);
251 }
252
253 int
ns_sign_tcp_init(void * k,const u_char * querysig,int querysiglen,ns_tcp_tsig_state * state)254 ns_sign_tcp_init(void *k, const u_char *querysig, int querysiglen,
255 ns_tcp_tsig_state *state)
256 {
257 dst_init();
258 if (state == NULL || k == NULL || querysig == NULL || querysiglen < 0)
259 return (-1);
260 state->counter = -1;
261 state->key = k;
262 if (state->key->dk_alg != KEY_HMAC_MD5)
263 return (-ns_r_badkey);
264 if (querysiglen > (int)sizeof(state->sig))
265 return (-1);
266 memcpy(state->sig, querysig, querysiglen);
267 state->siglen = querysiglen;
268 return (0);
269 }
270
271 int
ns_sign_tcp(u_char * msg,int * msglen,int msgsize,int error,ns_tcp_tsig_state * state,int done)272 ns_sign_tcp(u_char *msg, int *msglen, int msgsize, int error,
273 ns_tcp_tsig_state *state, int done)
274 {
275 return (ns_sign_tcp2(msg, msglen, msgsize, error, state,
276 done, NULL, NULL));
277 }
278
279 int
ns_sign_tcp2(u_char * msg,int * msglen,int msgsize,int error,ns_tcp_tsig_state * state,int done,u_char ** dnptrs,u_char ** lastdnptr)280 ns_sign_tcp2(u_char *msg, int *msglen, int msgsize, int error,
281 ns_tcp_tsig_state *state, int done,
282 u_char **dnptrs, u_char **lastdnptr)
283 {
284 u_char *cp, *eob, *lenp;
285 u_char buf[MAXDNAME], *cp2;
286 HEADER *hp = (HEADER *)msg;
287 time_t timesigned;
288 int n;
289
290 if (msg == NULL || msglen == NULL || state == NULL)
291 return (-1);
292
293 state->counter++;
294 if (state->counter == 0)
295 return (ns_sign2(msg, msglen, msgsize, error, state->key,
296 state->sig, state->siglen,
297 state->sig, &state->siglen, 0,
298 dnptrs, lastdnptr));
299
300 if (state->siglen > 0) {
301 u_int16_t siglen_n = htons(state->siglen);
302 dst_sign_data(SIG_MODE_INIT, state->key, &state->ctx,
303 NULL, 0, NULL, 0);
304 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
305 (u_char *)&siglen_n, INT16SZ, NULL, 0);
306 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
307 state->sig, state->siglen, NULL, 0);
308 state->siglen = 0;
309 }
310
311 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx, msg, *msglen,
312 NULL, 0);
313
314 if (done == 0 && (state->counter % 100 != 0))
315 return (0);
316
317 cp = msg + *msglen;
318 eob = msg + msgsize;
319
320 /* Name. */
321 n = dn_comp(state->key->dk_key_name, cp, eob - cp, dnptrs, lastdnptr);
322 if (n < 0)
323 return (NS_TSIG_ERROR_NO_SPACE);
324 cp += n;
325
326 /* Type, class, ttl, length (not filled in yet). */
327 BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
328 PUTSHORT(ns_t_tsig, cp);
329 PUTSHORT(ns_c_any, cp);
330 PUTLONG(0, cp); /*%< TTL */
331 lenp = cp;
332 cp += 2;
333
334 /* Alg. */
335 n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
336 if (n < 0)
337 return (NS_TSIG_ERROR_NO_SPACE);
338 cp += n;
339
340 /* Time. */
341 BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
342 PUTSHORT(0, cp);
343 timesigned = time(NULL);
344 PUTLONG(timesigned, cp);
345 PUTSHORT(NS_TSIG_FUDGE, cp);
346
347 /*
348 * Compute the signature.
349 */
350
351 /* Digest the time signed and fudge. */
352 cp2 = buf;
353 PUTSHORT(0, cp2); /*%< Top 16 bits of time */
354 PUTLONG(timesigned, cp2);
355 PUTSHORT(NS_TSIG_FUDGE, cp2);
356
357 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
358 buf, cp2 - buf, NULL, 0);
359
360 n = dst_sign_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
361 state->sig, sizeof(state->sig));
362 if (n < 0)
363 return (-ns_r_badkey);
364 state->siglen = n;
365
366 /* Add the signature. */
367 BOUNDS_CHECK(cp, INT16SZ + state->siglen);
368 PUTSHORT(state->siglen, cp);
369 memcpy(cp, state->sig, state->siglen);
370 cp += state->siglen;
371
372 /* The original message ID & error. */
373 BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
374 PUTSHORT(ntohs(hp->id), cp); /*%< already in network order */
375 PUTSHORT(error, cp);
376
377 /* Other data. */
378 BOUNDS_CHECK(cp, INT16SZ);
379 PUTSHORT(0, cp);
380
381 /* Go back and fill in the length. */
382 PUTSHORT(cp - lenp - INT16SZ, lenp);
383
384 hp->arcount = htons(ntohs(hp->arcount) + 1);
385 *msglen = (cp - msg);
386 return (0);
387 }
388
389 /*! \file */
390