/src/openssl30/crypto/ec/ecp_oct.c

Source (jump to first uncovered line)
/*
 * Copyright 2011-2021 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/*
 * ECDSA low level APIs are deprecated for public use, but still ok for
 * internal use.
 */
#include "internal/deprecated.h"

#include <openssl/err.h>
#include <openssl/symhacks.h>

#include "ec_local.h"

int ossl_ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group,
                                                  EC_POINT *point,
                                                  const BIGNUM *x_, int y_bit,
                                                  BN_CTX *ctx)
{
    BN_CTX *new_ctx = NULL;
    BIGNUM *tmp1, *tmp2, *x, *y;
    int ret = 0;

    if (ctx == NULL) {
        ctx = new_ctx = BN_CTX_new_ex(group->libctx);
        if (ctx == NULL)
            return 0;
    }

    y_bit = (y_bit != 0);

    BN_CTX_start(ctx);
    tmp1 = BN_CTX_get(ctx);
    tmp2 = BN_CTX_get(ctx);
    x = BN_CTX_get(ctx);
    y = BN_CTX_get(ctx);
    if (y == NULL)
        goto err;

    /*-
     * Recover y.  We have a Weierstrass equation
     *     y^2 = x^3 + a*x + b,
     * so  y  is one of the square roots of  x^3 + a*x + b.
     */

    /* tmp1 := x^3 */
    if (!BN_nnmod(x, x_, group->field, ctx))
        goto err;
    if (group->meth->field_decode == 0) {
        /* field_{sqr,mul} work on standard representation */
        if (!group->meth->field_sqr(group, tmp2, x_, ctx))
            goto err;
        if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx))
            goto err;
    } else {
        if (!BN_mod_sqr(tmp2, x_, group->field, ctx))
            goto err;
        if (!BN_mod_mul(tmp1, tmp2, x_, group->field, ctx))
            goto err;
    }

    /* tmp1 := tmp1 + a*x */
    if (group->a_is_minus3) {
        if (!BN_mod_lshift1_quick(tmp2, x, group->field))
            goto err;
        if (!BN_mod_add_quick(tmp2, tmp2, x, group->field))
            goto err;
        if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, group->field))
            goto err;
    } else {
        if (group->meth->field_decode) {
            if (!group->meth->field_decode(group, tmp2, group->a, ctx))
                goto err;
            if (!BN_mod_mul(tmp2, tmp2, x, group->field, ctx))
                goto err;
        } else {
            /* field_mul works on standard representation */
            if (!group->meth->field_mul(group, tmp2, group->a, x, ctx))
                goto err;
        }

        if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
            goto err;
    }

    /* tmp1 := tmp1 + b */
    if (group->meth->field_decode) {
        if (!group->meth->field_decode(group, tmp2, group->b, ctx))
            goto err;
        if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
            goto err;
    } else {
        if (!BN_mod_add_quick(tmp1, tmp1, group->b, group->field))
            goto err;
    }

    ERR_set_mark();
    if (!BN_mod_sqrt(y, tmp1, group->field, ctx)) {
#ifndef FIPS_MODULE
        unsigned long err = ERR_peek_last_error();

        if (ERR_GET_LIB(err) == ERR_LIB_BN
            && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) {
            ERR_pop_to_mark();
            ERR_raise(ERR_LIB_EC, EC_R_INVALID_COMPRESSED_POINT);
        } else
#endif
        {
            ERR_clear_last_mark();
            ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
        }
        goto err;
    }
    ERR_clear_last_mark();

    if (y_bit != BN_is_odd(y)) {
        if (BN_is_zero(y)) {
            int kron;

            kron = BN_kronecker(x, group->field, ctx);
            if (kron == -2)
                goto err;

            if (kron == 1)
                ERR_raise(ERR_LIB_EC, EC_R_INVALID_COMPRESSION_BIT);
            else
                /*
                 * BN_mod_sqrt() should have caught this error (not a square)
                 */
                ERR_raise(ERR_LIB_EC, EC_R_INVALID_COMPRESSED_POINT);
            goto err;
        }
        if (!BN_usub(y, group->field, y))
            goto err;
    }
    if (y_bit != BN_is_odd(y)) {
        ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
        goto err;
    }

    if (!EC_POINT_set_affine_coordinates(group, point, x, y, ctx))
        goto err;

    ret = 1;

 err:
    BN_CTX_end(ctx);
    BN_CTX_free(new_ctx);
    return ret;
}

size_t ossl_ec_GFp_simple_point2oct(const EC_GROUP *group, const EC_POINT *point,
                                    point_conversion_form_t form,
                                    unsigned char *buf, size_t len, BN_CTX *ctx)
{
    size_t ret;
    BN_CTX *new_ctx = NULL;
    int used_ctx = 0;
    BIGNUM *x, *y;
    size_t field_len, i, skip;

    if ((form != POINT_CONVERSION_COMPRESSED)
        && (form != POINT_CONVERSION_UNCOMPRESSED)
        && (form != POINT_CONVERSION_HYBRID)) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_FORM);
        goto err;
    }

    if (EC_POINT_is_at_infinity(group, point)) {
        /* encodes to a single 0 octet */
        if (buf != NULL) {
            if (len < 1) {
                ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
                return 0;
            }
            buf[0] = 0;
        }
        return 1;
    }

    /* ret := required output buffer length */
    field_len = BN_num_bytes(group->field);
    ret =
        (form ==
         POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;

    /* if 'buf' is NULL, just return required length */
    if (buf != NULL) {
        if (len < ret) {
            ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
            goto err;
        }

        if (ctx == NULL) {
            ctx = new_ctx = BN_CTX_new_ex(group->libctx);
            if (ctx == NULL)
                return 0;
        }

        BN_CTX_start(ctx);
        used_ctx = 1;
        x = BN_CTX_get(ctx);
        y = BN_CTX_get(ctx);
        if (y == NULL)
            goto err;

        if (!EC_POINT_get_affine_coordinates(group, point, x, y, ctx))
            goto err;

        if ((form == POINT_CONVERSION_COMPRESSED
             || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
            buf[0] = form + 1;
        else
            buf[0] = form;

        i = 1;

        skip = field_len - BN_num_bytes(x);
        if (skip > field_len) {
            ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
            goto err;
        }
        while (skip > 0) {
            buf[i++] = 0;
            skip--;
        }
        skip = BN_bn2bin(x, buf + i);
        i += skip;
        if (i != 1 + field_len) {
            ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
            goto err;
        }

        if (form == POINT_CONVERSION_UNCOMPRESSED
            || form == POINT_CONVERSION_HYBRID) {
            skip = field_len - BN_num_bytes(y);
            if (skip > field_len) {
                ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
                goto err;
            }
            while (skip > 0) {
                buf[i++] = 0;
                skip--;
            }
            skip = BN_bn2bin(y, buf + i);
            i += skip;
        }

        if (i != ret) {
            ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
            goto err;
        }
    }

    if (used_ctx)
        BN_CTX_end(ctx);
    BN_CTX_free(new_ctx);
    return ret;

 err:
    if (used_ctx)
        BN_CTX_end(ctx);
    BN_CTX_free(new_ctx);
    return 0;
}

int ossl_ec_GFp_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
                                 const unsigned char *buf, size_t len,
                                 BN_CTX *ctx)
{
    point_conversion_form_t form;
    int y_bit;
    BN_CTX *new_ctx = NULL;
    BIGNUM *x, *y;
    size_t field_len, enc_len;
    int ret = 0;

    if (len == 0) {
        ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
        return 0;
    }
    form = buf[0];
    y_bit = form & 1;
    form = form & ~1U;
    if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
        && (form != POINT_CONVERSION_UNCOMPRESSED)
        && (form != POINT_CONVERSION_HYBRID)) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
        return 0;
    }
    if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
        return 0;
    }

    if (form == 0) {
        if (len != 1) {
            ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
            return 0;
        }

        return EC_POINT_set_to_infinity(group, point);
    }

    field_len = BN_num_bytes(group->field);
    enc_len =
        (form ==
         POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;

    if (len != enc_len) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
        return 0;
    }

    if (ctx == NULL) {
        ctx = new_ctx = BN_CTX_new_ex(group->libctx);
        if (ctx == NULL)
            return 0;
    }

    BN_CTX_start(ctx);
    x = BN_CTX_get(ctx);
    y = BN_CTX_get(ctx);
    if (y == NULL)
        goto err;

    if (!BN_bin2bn(buf + 1, field_len, x))
        goto err;
    if (BN_ucmp(x, group->field) >= 0) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
        goto err;
    }

    if (form == POINT_CONVERSION_COMPRESSED) {
        if (!EC_POINT_set_compressed_coordinates(group, point, x, y_bit, ctx))
            goto err;
    } else {
        if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
            goto err;
        if (BN_ucmp(y, group->field) >= 0) {
            ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
            goto err;
        }
        if (form == POINT_CONVERSION_HYBRID) {
            if (y_bit != BN_is_odd(y)) {
                ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
                goto err;
            }
        }

        /*
         * EC_POINT_set_affine_coordinates is responsible for checking that
         * the point is on the curve.
         */
        if (!EC_POINT_set_affine_coordinates(group, point, x, y, ctx))
            goto err;
    }

    ret = 1;

 err:
    BN_CTX_end(ctx);
    BN_CTX_free(new_ctx);
    return ret;
}

Coverage Report

Created: 2023-09-25 06:45

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 2011-2021 The OpenSSL Project Authors. All Rights Reserved.
3		* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
4		*
5		* Licensed under the Apache License 2.0 (the "License"). You may not use
6		* this file except in compliance with the License. You can obtain a copy
7		* in the file LICENSE in the source distribution or at
8		* https://www.openssl.org/source/license.html
9		*/
10
11		/*
12		* ECDSA low level APIs are deprecated for public use, but still ok for
13		* internal use.
14		*/
15		#include "internal/deprecated.h"
16
17		#include <openssl/err.h>
18		#include <openssl/symhacks.h>
19
20		#include "ec_local.h"
21
22		int ossl_ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group,
23		EC_POINT *point,
24		const BIGNUM *x_, int y_bit,
25		BN_CTX *ctx)
26	61.4k	{
27	61.4k	BN_CTX *new_ctx = NULL;
28	61.4k	BIGNUM tmp1, tmp2, x, y;
29	61.4k	int ret = 0;
30
31	61.4k	if (ctx == NULL) {
32	0	ctx = new_ctx = BN_CTX_new_ex(group->libctx);
33	0	if (ctx == NULL)
34	0	return 0;
35	0	}
36
37	61.4k	y_bit = (y_bit != 0);
38
39	61.4k	BN_CTX_start(ctx);
40	61.4k	tmp1 = BN_CTX_get(ctx);
41	61.4k	tmp2 = BN_CTX_get(ctx);
42	61.4k	x = BN_CTX_get(ctx);
43	61.4k	y = BN_CTX_get(ctx);
44	61.4k	if (y == NULL)
45	0	goto err;
46
47		/*-
48		* Recover y. We have a Weierstrass equation
49		* y^2 = x^3 + a*x + b,
50		* so y is one of the square roots of x^3 + a*x + b.
51		*/
52
53		/* tmp1 := x^3 */
54	61.4k	if (!BN_nnmod(x, x_, group->field, ctx))
55	0	goto err;
56	61.4k	if (group->meth->field_decode == 0) {
57		/* field_{sqr,mul} work on standard representation */
58	21.8k	if (!group->meth->field_sqr(group, tmp2, x_, ctx))
59	0	goto err;
60	21.8k	if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx))
61	0	goto err;
62	39.5k	} else {
63	39.5k	if (!BN_mod_sqr(tmp2, x_, group->field, ctx))
64	0	goto err;
65	39.5k	if (!BN_mod_mul(tmp1, tmp2, x_, group->field, ctx))
66	0	goto err;
67	39.5k	}
68
69		/* tmp1 := tmp1 + ax /
70	61.4k	if (group->a_is_minus3) {
71	46.6k	if (!BN_mod_lshift1_quick(tmp2, x, group->field))
72	0	goto err;
73	46.6k	if (!BN_mod_add_quick(tmp2, tmp2, x, group->field))
74	0	goto err;
75	46.6k	if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, group->field))
76	0	goto err;
77	46.6k	} else {
78	14.7k	if (group->meth->field_decode) {
79	14.7k	if (!group->meth->field_decode(group, tmp2, group->a, ctx))
80	0	goto err;
81	14.7k	if (!BN_mod_mul(tmp2, tmp2, x, group->field, ctx))
82	0	goto err;
83	14.7k	} else {
84		/* field_mul works on standard representation */
85	0	if (!group->meth->field_mul(group, tmp2, group->a, x, ctx))
86	0	goto err;
87	0	}
88
89	14.7k	if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
90	0	goto err;
91	14.7k	}
92
93		/* tmp1 := tmp1 + b */
94	61.4k	if (group->meth->field_decode) {
95	39.5k	if (!group->meth->field_decode(group, tmp2, group->b, ctx))
96	0	goto err;
97	39.5k	if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
98	0	goto err;
99	39.5k	} else {
100	21.8k	if (!BN_mod_add_quick(tmp1, tmp1, group->b, group->field))
101	0	goto err;
102	21.8k	}
103
104	61.4k	ERR_set_mark();
105	61.4k	if (!BN_mod_sqrt(y, tmp1, group->field, ctx)) {
106	18.5k	#ifndef FIPS_MODULE
107	18.5k	unsigned long err = ERR_peek_last_error();
108
109	18.5k	if (ERR_GET_LIB(err) == ERR_LIB_BN
110	18.5k	&& ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) {
111	18.2k	ERR_pop_to_mark();
112	18.2k	ERR_raise(ERR_LIB_EC, EC_R_INVALID_COMPRESSED_POINT);
113	18.2k	} else
114	270	#endif
115	270	{
116	270	ERR_clear_last_mark();
117	270	ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
118	270	}
119	18.5k	goto err;
120	18.5k	}
121	42.9k	ERR_clear_last_mark();
122
123	42.9k	if (y_bit != BN_is_odd(y)) {
124	20.4k	if (BN_is_zero(y)) {
125	14	int kron;
126
127	14	kron = BN_kronecker(x, group->field, ctx);
128	14	if (kron == -2)
129	0	goto err;
130
131	14	if (kron == 1)
132	14	ERR_raise(ERR_LIB_EC, EC_R_INVALID_COMPRESSION_BIT);
133	14	else
134		/*
135		* BN_mod_sqrt() should have caught this error (not a square)
136		*/
137	14	ERR_raise(ERR_LIB_EC, EC_R_INVALID_COMPRESSED_POINT);
138	14	goto err;
139	14	}
140	20.3k	if (!BN_usub(y, group->field, y))
141	0	goto err;
142	20.3k	}
143	42.8k	if (y_bit != BN_is_odd(y)) {
144	0	ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
145	0	goto err;
146	0	}
147
148	42.8k	if (!EC_POINT_set_affine_coordinates(group, point, x, y, ctx))
149	0	goto err;
150
151	42.8k	ret = 1;
152
153	61.4k	err:
154	61.4k	BN_CTX_end(ctx);
155	61.4k	BN_CTX_free(new_ctx);
156	61.4k	return ret;
157	42.8k	}
158
159		size_t ossl_ec_GFp_simple_point2oct(const EC_GROUP group, const EC_POINT point,
160		point_conversion_form_t form,
161		unsigned char buf, size_t len, BN_CTX ctx)
162	50.3k	{
163	50.3k	size_t ret;
164	50.3k	BN_CTX *new_ctx = NULL;
165	50.3k	int used_ctx = 0;
166	50.3k	BIGNUM x, y;
167	50.3k	size_t field_len, i, skip;
168
169	50.3k	if ((form != POINT_CONVERSION_COMPRESSED)
170	50.3k	&& (form != POINT_CONVERSION_UNCOMPRESSED)
171	50.3k	&& (form != POINT_CONVERSION_HYBRID)) {
172	57	ERR_raise(ERR_LIB_EC, EC_R_INVALID_FORM);
173	57	goto err;
174	57	}
175
176	50.2k	if (EC_POINT_is_at_infinity(group, point)) {
177		/* encodes to a single 0 octet */
178	320	if (buf != NULL) {
179	160	if (len < 1) {
180	0	ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
181	0	return 0;
182	0	}
183	160	buf[0] = 0;
184	160	}
185	320	return 1;
186	320	}
187
188		/* ret := required output buffer length */
189	49.9k	field_len = BN_num_bytes(group->field);
190	49.9k	ret =
191	49.9k	(form ==
192	49.9k	POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
193
194		/* if 'buf' is NULL, just return required length */
195	49.9k	if (buf != NULL) {
196	24.9k	if (len < ret) {
197	0	ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
198	0	goto err;
199	0	}
200
201	24.9k	if (ctx == NULL) {
202	2.64k	ctx = new_ctx = BN_CTX_new_ex(group->libctx);
203	2.64k	if (ctx == NULL)
204	0	return 0;
205	2.64k	}
206
207	24.9k	BN_CTX_start(ctx);
208	24.9k	used_ctx = 1;
209	24.9k	x = BN_CTX_get(ctx);
210	24.9k	y = BN_CTX_get(ctx);
211	24.9k	if (y == NULL)
212	0	goto err;
213
214	24.9k	if (!EC_POINT_get_affine_coordinates(group, point, x, y, ctx))
215	0	goto err;
216
217	24.9k	if ((form == POINT_CONVERSION_COMPRESSED
218	24.9k	\|\| form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
219	465	buf[0] = form + 1;
220	24.5k	else
221	24.5k	buf[0] = form;
222
223	24.9k	i = 1;
224
225	24.9k	skip = field_len - BN_num_bytes(x);
226	24.9k	if (skip > field_len) {
227	0	ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
228	0	goto err;
229	0	}
230	35.8k	while (skip > 0) {
231	10.9k	buf[i++] = 0;
232	10.9k	skip--;
233	10.9k	}
234	24.9k	skip = BN_bn2bin(x, buf + i);
235	24.9k	i += skip;
236	24.9k	if (i != 1 + field_len) {
237	0	ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
238	0	goto err;
239	0	}
240
241	24.9k	if (form == POINT_CONVERSION_UNCOMPRESSED
242	24.9k	\|\| form == POINT_CONVERSION_HYBRID) {
243	23.0k	skip = field_len - BN_num_bytes(y);
244	23.0k	if (skip > field_len) {
245	0	ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
246	0	goto err;
247	0	}
248	24.4k	while (skip > 0) {
249	1.47k	buf[i++] = 0;
250	1.47k	skip--;
251	1.47k	}
252	23.0k	skip = BN_bn2bin(y, buf + i);
253	23.0k	i += skip;
254	23.0k	}
255
256	24.9k	if (i != ret) {
257	0	ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
258	0	goto err;
259	0	}
260	24.9k	}
261
262	49.9k	if (used_ctx)
263	24.9k	BN_CTX_end(ctx);
264	49.9k	BN_CTX_free(new_ctx);
265	49.9k	return ret;
266
267	57	err:
268	57	if (used_ctx)
269	0	BN_CTX_end(ctx);
270	57	BN_CTX_free(new_ctx);
271	57	return 0;
272	49.9k	}
273
274		int ossl_ec_GFp_simple_oct2point(const EC_GROUP group, EC_POINT point,
275		const unsigned char *buf, size_t len,
276		BN_CTX *ctx)
277	130k	{
278	130k	point_conversion_form_t form;
279	130k	int y_bit;
280	130k	BN_CTX *new_ctx = NULL;
281	130k	BIGNUM x, y;
282	130k	size_t field_len, enc_len;
283	130k	int ret = 0;
284
285	130k	if (len == 0) {
286	5.44k	ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
287	5.44k	return 0;
288	5.44k	}
289	125k	form = buf[0];
290	125k	y_bit = form & 1;
291	125k	form = form & ~1U;
292	125k	if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
293	125k	&& (form != POINT_CONVERSION_UNCOMPRESSED)
294	125k	&& (form != POINT_CONVERSION_HYBRID)) {
295	2.68k	ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
296	2.68k	return 0;
297	2.68k	}
298	122k	if ((form == 0 \|\| form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
299	931	ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
300	931	return 0;
301	931	}
302
303	121k	if (form == 0) {
304	4.60k	if (len != 1) {
305	1.04k	ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
306	1.04k	return 0;
307	1.04k	}
308
309	3.56k	return EC_POINT_set_to_infinity(group, point);
310	4.60k	}
311
312	117k	field_len = BN_num_bytes(group->field);
313	117k	enc_len =
314	117k	(form ==
315	117k	POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
316
317	117k	if (len != enc_len) {
318	3.35k	ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
319	3.35k	return 0;
320	3.35k	}
321
322	113k	if (ctx == NULL) {
323	91.9k	ctx = new_ctx = BN_CTX_new_ex(group->libctx);
324	91.9k	if (ctx == NULL)
325	0	return 0;
326	91.9k	}
327
328	113k	BN_CTX_start(ctx);
329	113k	x = BN_CTX_get(ctx);
330	113k	y = BN_CTX_get(ctx);
331	113k	if (y == NULL)
332	0	goto err;
333
334	113k	if (!BN_bin2bn(buf + 1, field_len, x))
335	0	goto err;
336	113k	if (BN_ucmp(x, group->field) >= 0) {
337	668	ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
338	668	goto err;
339	668	}
340
341	112k	if (form == POINT_CONVERSION_COMPRESSED) {
342	61.4k	if (!EC_POINT_set_compressed_coordinates(group, point, x, y_bit, ctx))
343	18.5k	goto err;
344	61.4k	} else {
345	51.5k	if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
346	0	goto err;
347	51.5k	if (BN_ucmp(y, group->field) >= 0) {
348	255	ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
349	255	goto err;
350	255	}
351	51.3k	if (form == POINT_CONVERSION_HYBRID) {
352	2.91k	if (y_bit != BN_is_odd(y)) {
353	769	ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
354	769	goto err;
355	769	}
356	2.91k	}
357
358		/*
359		* EC_POINT_set_affine_coordinates is responsible for checking that
360		* the point is on the curve.
361		*/
362	50.5k	if (!EC_POINT_set_affine_coordinates(group, point, x, y, ctx))
363	4.71k	goto err;
364	50.5k	}
365
366	88.7k	ret = 1;
367
368	113k	err:
369	113k	BN_CTX_end(ctx);
370	113k	BN_CTX_free(new_ctx);
371	113k	return ret;
372	88.7k	}