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