GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libcrypto/ec/ecp_oct.c Lines: 110 174 63.2 %
Date: 2017-11-07 Branches: 83 166 50.0 %

Line Branch Exec Source
1
/* $OpenBSD: ecp_oct.c,v 1.8 2017/01/29 17:49:23 beck Exp $ */
2
/* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
3
 * for the OpenSSL project.
4
 * Includes code written by Bodo Moeller for the OpenSSL project.
5
*/
6
/* ====================================================================
7
 * Copyright (c) 1998-2002 The OpenSSL Project.  All rights reserved.
8
 *
9
 * Redistribution and use in source and binary forms, with or without
10
 * modification, are permitted provided that the following conditions
11
 * are met:
12
 *
13
 * 1. Redistributions of source code must retain the above copyright
14
 *    notice, this list of conditions and the following disclaimer.
15
 *
16
 * 2. Redistributions in binary form must reproduce the above copyright
17
 *    notice, this list of conditions and the following disclaimer in
18
 *    the documentation and/or other materials provided with the
19
 *    distribution.
20
 *
21
 * 3. All advertising materials mentioning features or use of this
22
 *    software must display the following acknowledgment:
23
 *    "This product includes software developed by the OpenSSL Project
24
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
25
 *
26
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27
 *    endorse or promote products derived from this software without
28
 *    prior written permission. For written permission, please contact
29
 *    openssl-core@openssl.org.
30
 *
31
 * 5. Products derived from this software may not be called "OpenSSL"
32
 *    nor may "OpenSSL" appear in their names without prior written
33
 *    permission of the OpenSSL Project.
34
 *
35
 * 6. Redistributions of any form whatsoever must retain the following
36
 *    acknowledgment:
37
 *    "This product includes software developed by the OpenSSL Project
38
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
39
 *
40
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
44
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51
 * OF THE POSSIBILITY OF SUCH DAMAGE.
52
 * ====================================================================
53
 *
54
 * This product includes cryptographic software written by Eric Young
55
 * (eay@cryptsoft.com).  This product includes software written by Tim
56
 * Hudson (tjh@cryptsoft.com).
57
 *
58
 */
59
/* ====================================================================
60
 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
61
 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
62
 * and contributed to the OpenSSL project.
63
 */
64
65
#include <openssl/err.h>
66
67
#include "ec_lcl.h"
68
69
int
70
ec_GFp_simple_set_compressed_coordinates(const EC_GROUP * group,
71
    EC_POINT * point, const BIGNUM * x_, int y_bit, BN_CTX * ctx)
72
{
73
	BN_CTX *new_ctx = NULL;
74
	BIGNUM *tmp1, *tmp2, *x, *y;
75
	int ret = 0;
76
77
	/* clear error queue */
78
276
	ERR_clear_error();
79
80
138
	if (ctx == NULL) {
81
		ctx = new_ctx = BN_CTX_new();
82
		if (ctx == NULL)
83
			return 0;
84
	}
85
138
	y_bit = (y_bit != 0);
86
87
138
	BN_CTX_start(ctx);
88
138
	if ((tmp1 = BN_CTX_get(ctx)) == NULL)
89
		goto err;
90
138
	if ((tmp2 = BN_CTX_get(ctx)) == NULL)
91
		goto err;
92
138
	if ((x = BN_CTX_get(ctx)) == NULL)
93
		goto err;
94
138
	if ((y = BN_CTX_get(ctx)) == NULL)
95
		goto err;
96
97
	/*
98
	 * Recover y.  We have a Weierstrass equation y^2 = x^3 + a*x + b, so
99
	 * y  is one of the square roots of  x^3 + a*x + b.
100
	 */
101
102
	/* tmp1 := x^3 */
103
138
	if (!BN_nnmod(x, x_, &group->field, ctx))
104
		goto err;
105
138
	if (group->meth->field_decode == 0) {
106
		/* field_{sqr,mul} work on standard representation */
107
		if (!group->meth->field_sqr(group, tmp2, x_, ctx))
108
			goto err;
109
		if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx))
110
			goto err;
111
	} else {
112
138
		if (!BN_mod_sqr(tmp2, x_, &group->field, ctx))
113
			goto err;
114
138
		if (!BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx))
115
			goto err;
116
	}
117
118
	/* tmp1 := tmp1 + a*x */
119
138
	if (group->a_is_minus3) {
120
94
		if (!BN_mod_lshift1_quick(tmp2, x, &group->field))
121
			goto err;
122
94
		if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field))
123
			goto err;
124
94
		if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field))
125
			goto err;
126
	} else {
127
44
		if (group->meth->field_decode) {
128
44
			if (!group->meth->field_decode(group, tmp2, &group->a, ctx))
129
				goto err;
130
44
			if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx))
131
				goto err;
132
		} else {
133
			/* field_mul works on standard representation */
134
			if (!group->meth->field_mul(group, tmp2, &group->a, x, ctx))
135
				goto err;
136
		}
137
138
44
		if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field))
139
			goto err;
140
	}
141
142
	/* tmp1 := tmp1 + b */
143
138
	if (group->meth->field_decode) {
144
138
		if (!group->meth->field_decode(group, tmp2, &group->b, ctx))
145
			goto err;
146
138
		if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field))
147
			goto err;
148
	} else {
149
		if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field))
150
			goto err;
151
	}
152
153
138
	if (!BN_mod_sqrt(y, tmp1, &group->field, ctx)) {
154
		unsigned long err = ERR_peek_last_error();
155
156
		if (ERR_GET_LIB(err) == ERR_LIB_BN && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) {
157
			ERR_clear_error();
158
			ECerror(EC_R_INVALID_COMPRESSED_POINT);
159
		} else
160
			ECerror(ERR_R_BN_LIB);
161
		goto err;
162
	}
163

414
	if (y_bit != BN_is_odd(y)) {
164
62
		if (BN_is_zero(y)) {
165
			int kron;
166
167
			kron = BN_kronecker(x, &group->field, ctx);
168
			if (kron == -2)
169
				goto err;
170
171
			if (kron == 1)
172
				ECerror(EC_R_INVALID_COMPRESSION_BIT);
173
			else
174
				/*
175
				 * BN_mod_sqrt() should have cought this
176
				 * error (not a square)
177
				 */
178
				ECerror(EC_R_INVALID_COMPRESSED_POINT);
179
			goto err;
180
		}
181
62
		if (!BN_usub(y, &group->field, y))
182
			goto err;
183
	}
184

414
	if (y_bit != BN_is_odd(y)) {
185
		ECerror(ERR_R_INTERNAL_ERROR);
186
		goto err;
187
	}
188
138
	if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
189
		goto err;
190
191
138
	ret = 1;
192
193
err:
194
138
	BN_CTX_end(ctx);
195
138
	BN_CTX_free(new_ctx);
196
138
	return ret;
197
138
}
198
199
200
size_t
201
ec_GFp_simple_point2oct(const EC_GROUP * group, const EC_POINT * point, point_conversion_form_t form,
202
    unsigned char *buf, size_t len, BN_CTX * ctx)
203
{
204
	size_t ret;
205
	BN_CTX *new_ctx = NULL;
206
	int used_ctx = 0;
207
	BIGNUM *x, *y;
208
	size_t field_len, i, skip;
209
210
9444
	if ((form != POINT_CONVERSION_COMPRESSED)
211
9444
	    && (form != POINT_CONVERSION_UNCOMPRESSED)
212
4722
	    && (form != POINT_CONVERSION_HYBRID)) {
213
		ECerror(EC_R_INVALID_FORM);
214
		goto err;
215
	}
216
4722
	if (EC_POINT_is_at_infinity(group, point) > 0) {
217
		/* encodes to a single 0 octet */
218
		if (buf != NULL) {
219
			if (len < 1) {
220
				ECerror(EC_R_BUFFER_TOO_SMALL);
221
				return 0;
222
			}
223
			buf[0] = 0;
224
		}
225
		return 1;
226
	}
227
	/* ret := required output buffer length */
228
4722
	field_len = BN_num_bytes(&group->field);
229
4722
	ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
230
231
	/* if 'buf' is NULL, just return required length */
232
4722
	if (buf != NULL) {
233
2370
		if (len < ret) {
234
			ECerror(EC_R_BUFFER_TOO_SMALL);
235
			goto err;
236
		}
237
2370
		if (ctx == NULL) {
238
1078
			ctx = new_ctx = BN_CTX_new();
239
1078
			if (ctx == NULL)
240
				return 0;
241
		}
242
2370
		BN_CTX_start(ctx);
243
		used_ctx = 1;
244
2370
		if ((x = BN_CTX_get(ctx)) == NULL)
245
			goto err;
246
2370
		if ((y = BN_CTX_get(ctx)) == NULL)
247
			goto err;
248
249
2370
		if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx))
250
			goto err;
251
252

3930
		if ((form == POINT_CONVERSION_COMPRESSED || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
253
364
			buf[0] = form + 1;
254
		else
255
2006
			buf[0] = form;
256
257
		i = 1;
258
259
2370
		skip = field_len - BN_num_bytes(x);
260
2370
		if (skip > field_len) {
261
			ECerror(ERR_R_INTERNAL_ERROR);
262
			goto err;
263
		}
264
13488
		while (skip > 0) {
265
5559
			buf[i++] = 0;
266
5559
			skip--;
267
		}
268
2370
		skip = BN_bn2bin(x, buf + i);
269
2370
		i += skip;
270
2370
		if (i != 1 + field_len) {
271
			ECerror(ERR_R_INTERNAL_ERROR);
272
			goto err;
273
		}
274
2370
		if (form == POINT_CONVERSION_UNCOMPRESSED || form == POINT_CONVERSION_HYBRID) {
275
1596
			skip = field_len - BN_num_bytes(y);
276
1596
			if (skip > field_len) {
277
				ECerror(ERR_R_INTERNAL_ERROR);
278
				goto err;
279
			}
280
1612
			while (skip > 0) {
281
8
				buf[i++] = 0;
282
8
				skip--;
283
			}
284
1596
			skip = BN_bn2bin(y, buf + i);
285
1596
			i += skip;
286
1596
		}
287
2370
		if (i != ret) {
288
			ECerror(ERR_R_INTERNAL_ERROR);
289
			goto err;
290
		}
291
	}
292
4722
	if (used_ctx)
293
2370
		BN_CTX_end(ctx);
294
4722
	BN_CTX_free(new_ctx);
295
4722
	return ret;
296
297
err:
298
	if (used_ctx)
299
		BN_CTX_end(ctx);
300
	BN_CTX_free(new_ctx);
301
	return 0;
302
4722
}
303
304
305
int
306
ec_GFp_simple_oct2point(const EC_GROUP * group, EC_POINT * point,
307
    const unsigned char *buf, size_t len, BN_CTX * ctx)
308
{
309
	point_conversion_form_t form;
310
	int y_bit;
311
	BN_CTX *new_ctx = NULL;
312
	BIGNUM *x, *y;
313
	size_t field_len, enc_len;
314
	int ret = 0;
315
316
2584
	if (len == 0) {
317
		ECerror(EC_R_BUFFER_TOO_SMALL);
318
		return 0;
319
	}
320
1292
	form = buf[0];
321
1292
	y_bit = form & 1;
322
1292
	form = form & ~1U;
323
3876
	if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
324
1292
	    && (form != POINT_CONVERSION_UNCOMPRESSED)
325
1292
	    && (form != POINT_CONVERSION_HYBRID)) {
326
		ECerror(EC_R_INVALID_ENCODING);
327
		return 0;
328
	}
329
1292
	if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
330
		ECerror(EC_R_INVALID_ENCODING);
331
		return 0;
332
	}
333
1292
	if (form == 0) {
334
6
		if (len != 1) {
335
			ECerror(EC_R_INVALID_ENCODING);
336
			return 0;
337
		}
338
6
		return EC_POINT_set_to_infinity(group, point);
339
	}
340
1286
	field_len = BN_num_bytes(&group->field);
341
1286
	enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
342
343
1286
	if (len != enc_len) {
344
		ECerror(EC_R_INVALID_ENCODING);
345
		return 0;
346
	}
347
1286
	if (ctx == NULL) {
348
205
		ctx = new_ctx = BN_CTX_new();
349
205
		if (ctx == NULL)
350
			return 0;
351
	}
352
1286
	BN_CTX_start(ctx);
353
1286
	if ((x = BN_CTX_get(ctx)) == NULL)
354
		goto err;
355
1286
	if ((y = BN_CTX_get(ctx)) == NULL)
356
		goto err;
357
358
1286
	if (!BN_bin2bn(buf + 1, field_len, x))
359
		goto err;
360
1286
	if (BN_ucmp(x, &group->field) >= 0) {
361
		ECerror(EC_R_INVALID_ENCODING);
362
		goto err;
363
	}
364
1286
	if (form == POINT_CONVERSION_COMPRESSED) {
365
102
		if (!EC_POINT_set_compressed_coordinates_GFp(group, point, x, y_bit, ctx))
366
			goto err;
367
	} else {
368
1184
		if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
369
			goto err;
370
1184
		if (BN_ucmp(y, &group->field) >= 0) {
371
			ECerror(EC_R_INVALID_ENCODING);
372
			goto err;
373
		}
374
1184
		if (form == POINT_CONVERSION_HYBRID) {
375

18
			if (y_bit != BN_is_odd(y)) {
376
				ECerror(EC_R_INVALID_ENCODING);
377
				goto err;
378
			}
379
		}
380
1184
		if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
381
			goto err;
382
	}
383
384
	/* test required by X9.62 */
385
1286
	if (EC_POINT_is_on_curve(group, point, ctx) <= 0) {
386
		ECerror(EC_R_POINT_IS_NOT_ON_CURVE);
387
		goto err;
388
	}
389
1286
	ret = 1;
390
391
err:
392
1286
	BN_CTX_end(ctx);
393
1286
	BN_CTX_free(new_ctx);
394
1286
	return ret;
395
1292
}