aboutsummaryrefslogtreecommitdiff
path: root/contrib/isc-dhcp/minires/ns_sign.c
blob: 5cfd8f4d1a986e05c2fdaa3687dcb5e9c385ad07 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
/*
 * Copyright (c) 1999-2003 by Internet Software Consortium, Inc.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

#ifndef lint
static const char rcsid[] = "$Id: ns_sign.c,v 1.4.2.3 2003/01/14 23:15:06 dhankins Exp $";
#endif

#if defined (TRACING)
#define time(x)		trace_mr_time (x)
time_t trace_mr_time (time_t *);
#endif

/* Import. */

#include <sys/types.h>
#include <sys/param.h>

#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>

#include "minires/minires.h"
#include "arpa/nameser.h"

#include <isc-dhcp/dst.h>

#define BOUNDS_CHECK(ptr, count) \
	do { \
		if ((ptr) + (count) > eob) { \
			return ISC_R_NOSPACE; \
		} \
	} while (0)

/* ns_sign
 * Parameters:
 *	msg		message to be sent
 *	msglen		input - length of message
 *			output - length of signed message
 *	msgsize		length of buffer containing message
 *	error		value to put in the error field
 *	key		tsig key used for signing
 *	querysig	(response), the signature in the query
 *	querysiglen	(response), the length of the signature in the query
 *	sig		a buffer to hold the generated signature
 *	siglen		input - length of signature buffer
 *			output - length of signature
 *
 * Errors:
 *	- bad input data (-1)
 *	- bad key / sign failed (-BADKEY)
 *	- not enough space (NS_TSIG_ERROR_NO_SPACE)
 */
isc_result_t
ns_sign(u_char *msg, unsigned *msglen, unsigned msgsize, int error, void *k,
	const u_char *querysig, unsigned querysiglen, u_char *sig,
	unsigned *siglen, time_t in_timesigned)
{
	HEADER *hp = (HEADER *)msg;
	DST_KEY *key = (DST_KEY *)k;
	u_char *cp = msg + *msglen, *eob = msg + msgsize;
	u_char *lenp;
	u_char *name, *alg;
	unsigned n;
	time_t timesigned;

	dst_init();
	if (msg == NULL || msglen == NULL || sig == NULL || siglen == NULL)
		return ISC_R_INVALIDARG;

	/* Name. */
	if (key != NULL && error != ns_r_badsig && error != ns_r_badkey)
		n = dn_comp(key->dk_key_name,
			    cp, (unsigned)(eob - cp), NULL, NULL);
	else
		n = dn_comp("", cp, (unsigned)(eob - cp), NULL, NULL);
	if (n < 0)
		return ISC_R_NOSPACE;
	name = cp;
	cp += n;

	/* Type, class, ttl, length (not filled in yet). */
	BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
	PUTSHORT(ns_t_tsig, cp);
	PUTSHORT(ns_c_any, cp);
	PUTLONG(0, cp);		/* TTL */
	lenp = cp;
	cp += 2;

	/* Alg. */
	if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
		if (key->dk_alg != KEY_HMAC_MD5)
			return ISC_R_BADKEY;
		n = dn_comp(NS_TSIG_ALG_HMAC_MD5,
			    cp, (unsigned)(eob - cp), NULL, NULL);
	}
	else
		n = dn_comp("", cp, (unsigned)(eob - cp), NULL, NULL);
	if (n < 0)
		return ISC_R_NOSPACE;
	alg = cp;
	cp += n;
	
	/* Time. */
	BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
	PUTSHORT(0, cp);
	timesigned = time(NULL);
	if (error != ns_r_badtime)
		PUTLONG(timesigned, cp);
	else
		PUTLONG(in_timesigned, cp);
	PUTSHORT(NS_TSIG_FUDGE, cp);

	/* Compute the signature. */
	if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
		void *ctx;
		u_char buf[MAXDNAME], *cp2;
		unsigned n;

		dst_sign_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);

		/* Digest the query signature, if this is a response. */
		if (querysiglen > 0 && querysig != NULL) {
			u_int16_t len_n = htons(querysiglen);
			dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
				      (u_char *)&len_n, INT16SZ, NULL, 0);
			dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
				      querysig, querysiglen, NULL, 0);
		}

		/* Digest the message. */
		dst_sign_data(SIG_MODE_UPDATE, key, &ctx, msg, *msglen,
			      NULL, 0);

		/* Digest the key name. */
		n = ns_name_ntol(name, buf, sizeof(buf));
		dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);

		/* Digest the class and TTL. */
		cp2 = buf;
		PUTSHORT(ns_c_any, cp2);
		PUTLONG(0, cp2);
		dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
			      buf, (unsigned)(cp2-buf), NULL, 0);

		/* Digest the algorithm. */
		n = ns_name_ntol(alg, buf, sizeof(buf));
		dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);

		/* Digest the time signed, fudge, error, and other data */
		cp2 = buf;
		PUTSHORT(0, cp2);	/* Top 16 bits of time */
		if (error != ns_r_badtime)
			PUTLONG(timesigned, cp2);
		else
			PUTLONG(in_timesigned, cp2);
		PUTSHORT(NS_TSIG_FUDGE, cp2);
		PUTSHORT(error, cp2);	/* Error */
		if (error != ns_r_badtime)
			PUTSHORT(0, cp2);	/* Other data length */
		else {
			PUTSHORT(INT16SZ+INT32SZ, cp2);	/* Other data length */
			PUTSHORT(0, cp2);	/* Top 16 bits of time */
			PUTLONG(timesigned, cp2);
		}
		dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
			      buf, (unsigned)(cp2-buf), NULL, 0);

		n = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
				  sig, *siglen);
		if (n < 0)
			return ISC_R_BADKEY;
		*siglen = n;
	} else
		*siglen = 0;

	/* Add the signature. */
	BOUNDS_CHECK(cp, INT16SZ + (*siglen));
	PUTSHORT(*siglen, cp);
	memcpy(cp, sig, *siglen);
	cp += (*siglen);

	/* The original message ID & error. */
	BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
	PUTSHORT(ntohs(hp->id), cp);	/* already in network order */
	PUTSHORT(error, cp);

	/* Other data. */
	BOUNDS_CHECK(cp, INT16SZ);
	if (error != ns_r_badtime)
		PUTSHORT(0, cp);	/* Other data length */
	else {
		PUTSHORT(INT16SZ+INT32SZ, cp);	/* Other data length */
		BOUNDS_CHECK(cp, INT32SZ+INT16SZ);
		PUTSHORT(0, cp);	/* Top 16 bits of time */
		PUTLONG(timesigned, cp);
	}

	/* Go back and fill in the length. */
	PUTSHORT(cp - lenp - INT16SZ, lenp);

	hp->arcount = htons(ntohs(hp->arcount) + 1);
	*msglen = (cp - msg);
	return ISC_R_SUCCESS;
}

#if 0
isc_result_t
ns_sign_tcp_init(void *k, const u_char *querysig, unsigned querysiglen,
		 ns_tcp_tsig_state *state)
{
	dst_init();
	if (state == NULL || k == NULL || querysig == NULL || querysiglen < 0)
		return ISC_R_INVALIDARG;
	state->counter = -1;
	state->key = k;
	if (state->key->dk_alg != KEY_HMAC_MD5)
		return ISC_R_BADKEY;
	if (querysiglen > sizeof(state->sig))
		return ISC_R_NOSPACE;
	memcpy(state->sig, querysig, querysiglen);
	state->siglen = querysiglen;
	return ISC_R_SUCCESS;
}

isc_result_t
ns_sign_tcp(u_char *msg, unsigned *msglen, unsigned msgsize, int error,
	    ns_tcp_tsig_state *state, int done)
{
	u_char *cp, *eob, *lenp;
	u_char buf[MAXDNAME], *cp2;
	HEADER *hp = (HEADER *)msg;
	time_t timesigned;
	int n;

	if (msg == NULL || msglen == NULL || state == NULL)
		return ISC_R_INVALIDARG;

	state->counter++;
	if (state->counter == 0)
		return ns_sign(msg, msglen, msgsize, error, state->key,
			       state->sig, state->siglen,
			       state->sig, &state->siglen, 0);

	if (state->siglen > 0) {
		u_int16_t siglen_n = htons(state->siglen);
		dst_sign_data(SIG_MODE_INIT, state->key, &state->ctx,
			      NULL, 0, NULL, 0);
		dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
			      (u_char *)&siglen_n, INT16SZ, NULL, 0);
		dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
			      state->sig, state->siglen, NULL, 0);
		state->siglen = 0;
	}

	dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx, msg, *msglen,
		      NULL, 0);

	if (done == 0 && (state->counter % 100 != 0))
		return ISC_R_SUCCESS;

	cp = msg + *msglen;
	eob = msg + msgsize;

	/* Name. */
	n = dn_comp(state->key->dk_key_name,
		    cp, (unsigned)(eob - cp), NULL, NULL);
	if (n < 0)
		return ISC_R_NOSPACE;
	cp += n;

	/* Type, class, ttl, length (not filled in yet). */
	BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
	PUTSHORT(ns_t_tsig, cp);
	PUTSHORT(ns_c_any, cp);
	PUTLONG(0, cp);		/* TTL */
	lenp = cp;
	cp += 2;

	/* Alg. */
	n = dn_comp(NS_TSIG_ALG_HMAC_MD5,
		    cp, (unsigned)(eob - cp), NULL, NULL);
	if (n < 0)
		return ISC_R_NOSPACE;
	cp += n;
	
	/* Time. */
	BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
	PUTSHORT(0, cp);
	timesigned = time(NULL);
	PUTLONG(timesigned, cp);
	PUTSHORT(NS_TSIG_FUDGE, cp);

	/*
	 * Compute the signature.
	 */

	/* Digest the time signed and fudge. */
	cp2 = buf;
	PUTSHORT(0, cp2);	/* Top 16 bits of time */
	PUTLONG(timesigned, cp2);
	PUTSHORT(NS_TSIG_FUDGE, cp2);

	dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
		      buf, (unsigned)(cp2 - buf), NULL, 0);

	n = dst_sign_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
			  state->sig, sizeof(state->sig));
	if (n < 0)
		return ISC_R_BADKEY;
	state->siglen = n;

	/* Add the signature. */
	BOUNDS_CHECK(cp, INT16SZ + state->siglen);
	PUTSHORT(state->siglen, cp);
	memcpy(cp, state->sig, state->siglen);
	cp += state->siglen;

	/* The original message ID & error. */
	BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
	PUTSHORT(ntohs(hp->id), cp);	/* already in network order */
	PUTSHORT(error, cp);

	/* Other data. */
	BOUNDS_CHECK(cp, INT16SZ);
	PUTSHORT(0, cp);

	/* Go back and fill in the length. */
	PUTSHORT(cp - lenp - INT16SZ, lenp);

	hp->arcount = htons(ntohs(hp->arcount) + 1);
	*msglen = (cp - msg);
	return ISC_R_SUCCESS;
}
#endif