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