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
21static 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 */
79int
80ns_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
89int
90ns_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
253int
254ns_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
271int
272ns_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
279int
280ns_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