/src/openssl111/crypto/ec/ecp_oct.c

Source (jump to first uncovered line)
/*
 * Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
 *
 * Licensed under the OpenSSL license (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
 */

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

#include "ec_local.h"

int 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;

    /* clear error queue */
    ERR_clear_error();

    if (ctx == NULL) {
        ctx = new_ctx = BN_CTX_new();
        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;
    }

    if (!BN_mod_sqrt(y, tmp1, group->field, ctx)) {
        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_clear_error();
            ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
                  EC_R_INVALID_COMPRESSED_POINT);
        } else
            ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
                  ERR_R_BN_LIB);
        goto err;
    }

    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)
                ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
                      EC_R_INVALID_COMPRESSION_BIT);
            else
                /*
                 * BN_mod_sqrt() should have caught this error (not a square)
                 */
                ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
                      EC_R_INVALID_COMPRESSED_POINT);
            goto err;
        }
        if (!BN_usub(y, group->field, y))
            goto err;
    }
    if (y_bit != BN_is_odd(y)) {
        ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
              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 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)) {
        ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, 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) {
                ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, 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) {
            ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
            goto err;
        }

        if (ctx == NULL) {
            ctx = new_ctx = BN_CTX_new();
            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) {
            ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, 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) {
            ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, 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) {
                ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
                goto err;
            }
            while (skip > 0) {
                buf[i++] = 0;
                skip--;
            }
            skip = BN_bn2bin(y, buf + i);
            i += skip;
        }

        if (i != ret) {
            ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, 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 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) {
        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, 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)) {
        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
        return 0;
    }
    if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
        return 0;
    }

    if (form == 0) {
        if (len != 1) {
            ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, 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) {
        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
        return 0;
    }

    if (ctx == NULL) {
        ctx = new_ctx = BN_CTX_new();
        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) {
        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, 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) {
            ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
            goto err;
        }
        if (form == POINT_CONVERSION_HYBRID) {
            if (y_bit != BN_is_odd(y)) {
                ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, 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 06:42

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved.
3		* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
4		*
5		* Licensed under the OpenSSL license (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		#include <openssl/err.h>
12		#include <openssl/symhacks.h>
13
14		#include "ec_local.h"
15
16		int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group,
17		EC_POINT *point,
18		const BIGNUM *x_, int y_bit,
19		BN_CTX *ctx)
20	5.89k	{
21	5.89k	BN_CTX *new_ctx = NULL;
22	5.89k	BIGNUM tmp1, tmp2, x, y;
23	5.89k	int ret = 0;
24
25		/* clear error queue */
26	5.89k	ERR_clear_error();
27
28	5.89k	if (ctx == NULL) {
29	0	ctx = new_ctx = BN_CTX_new();
30	0	if (ctx == NULL)
31	0	return 0;
32	0	}
33
34	5.89k	y_bit = (y_bit != 0);
35
36	5.89k	BN_CTX_start(ctx);
37	5.89k	tmp1 = BN_CTX_get(ctx);
38	5.89k	tmp2 = BN_CTX_get(ctx);
39	5.89k	x = BN_CTX_get(ctx);
40	5.89k	y = BN_CTX_get(ctx);
41	5.89k	if (y == NULL)
42	0	goto err;
43
44		/*-
45		* Recover y. We have a Weierstrass equation
46		* y^2 = x^3 + a*x + b,
47		* so y is one of the square roots of x^3 + a*x + b.
48		*/
49
50		/* tmp1 := x^3 */
51	5.89k	if (!BN_nnmod(x, x_, group->field, ctx))
52	0	goto err;
53	5.89k	if (group->meth->field_decode == 0) {
54		/* field_{sqr,mul} work on standard representation */
55	3.21k	if (!group->meth->field_sqr(group, tmp2, x_, ctx))
56	0	goto err;
57	3.21k	if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx))
58	0	goto err;
59	3.21k	} else {
60	2.68k	if (!BN_mod_sqr(tmp2, x_, group->field, ctx))
61	0	goto err;
62	2.68k	if (!BN_mod_mul(tmp1, tmp2, x_, group->field, ctx))
63	0	goto err;
64	2.68k	}
65
66		/* tmp1 := tmp1 + ax /
67	5.89k	if (group->a_is_minus3) {
68	4.19k	if (!BN_mod_lshift1_quick(tmp2, x, group->field))
69	0	goto err;
70	4.19k	if (!BN_mod_add_quick(tmp2, tmp2, x, group->field))
71	0	goto err;
72	4.19k	if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, group->field))
73	0	goto err;
74	4.19k	} else {
75	1.70k	if (group->meth->field_decode) {
76	1.70k	if (!group->meth->field_decode(group, tmp2, group->a, ctx))
77	0	goto err;
78	1.70k	if (!BN_mod_mul(tmp2, tmp2, x, group->field, ctx))
79	0	goto err;
80	1.70k	} else {
81		/* field_mul works on standard representation */
82	0	if (!group->meth->field_mul(group, tmp2, group->a, x, ctx))
83	0	goto err;
84	0	}
85
86	1.70k	if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
87	0	goto err;
88	1.70k	}
89
90		/* tmp1 := tmp1 + b */
91	5.89k	if (group->meth->field_decode) {
92	2.68k	if (!group->meth->field_decode(group, tmp2, group->b, ctx))
93	0	goto err;
94	2.68k	if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
95	0	goto err;
96	3.21k	} else {
97	3.21k	if (!BN_mod_add_quick(tmp1, tmp1, group->b, group->field))
98	0	goto err;
99	3.21k	}
100
101	5.89k	if (!BN_mod_sqrt(y, tmp1, group->field, ctx)) {
102	2.09k	unsigned long err = ERR_peek_last_error();
103
104	2.09k	if (ERR_GET_LIB(err) == ERR_LIB_BN
105	2.09k	&& ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) {
106	2.05k	ERR_clear_error();
107	2.05k	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
108	2.05k	EC_R_INVALID_COMPRESSED_POINT);
109	2.05k	} else
110	2.09k	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
111	2.09k	ERR_R_BN_LIB);
112	2.09k	goto err;
113	2.09k	}
114
115	3.80k	if (y_bit != BN_is_odd(y)) {
116	1.89k	if (BN_is_zero(y)) {
117	2	int kron;
118
119	2	kron = BN_kronecker(x, group->field, ctx);
120	2	if (kron == -2)
121	0	goto err;
122
123	2	if (kron == 1)
124	2	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
125	2	EC_R_INVALID_COMPRESSION_BIT);
126	2	else
127		/*
128		* BN_mod_sqrt() should have caught this error (not a square)
129		*/
130	2	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
131	2	EC_R_INVALID_COMPRESSED_POINT);
132	2	goto err;
133	2	}
134	1.89k	if (!BN_usub(y, group->field, y))
135	0	goto err;
136	1.89k	}
137	3.80k	if (y_bit != BN_is_odd(y)) {
138	0	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
139	0	ERR_R_INTERNAL_ERROR);
140	0	goto err;
141	0	}
142
143	3.80k	if (!EC_POINT_set_affine_coordinates(group, point, x, y, ctx))
144	0	goto err;
145
146	3.80k	ret = 1;
147
148	5.89k	err:
149	5.89k	BN_CTX_end(ctx);
150	5.89k	BN_CTX_free(new_ctx);
151	5.89k	return ret;
152	3.80k	}
153
154		size_t ec_GFp_simple_point2oct(const EC_GROUP group, const EC_POINT point,
155		point_conversion_form_t form,
156		unsigned char buf, size_t len, BN_CTX ctx)
157	1.50k	{
158	1.50k	size_t ret;
159	1.50k	BN_CTX *new_ctx = NULL;
160	1.50k	int used_ctx = 0;
161	1.50k	BIGNUM x, y;
162	1.50k	size_t field_len, i, skip;
163
164	1.50k	if ((form != POINT_CONVERSION_COMPRESSED)
165	1.50k	&& (form != POINT_CONVERSION_UNCOMPRESSED)
166	1.50k	&& (form != POINT_CONVERSION_HYBRID)) {
167	4	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
168	4	goto err;
169	4	}
170
171	1.50k	if (EC_POINT_is_at_infinity(group, point)) {
172		/* encodes to a single 0 octet */
173	38	if (buf != NULL) {
174	19	if (len < 1) {
175	0	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
176	0	return 0;
177	0	}
178	19	buf[0] = 0;
179	19	}
180	38	return 1;
181	38	}
182
183		/* ret := required output buffer length */
184	1.46k	field_len = BN_num_bytes(group->field);
185	1.46k	ret =
186	1.46k	(form ==
187	1.46k	POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
188
189		/* if 'buf' is NULL, just return required length */
190	1.46k	if (buf != NULL) {
191	733	if (len < ret) {
192	0	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
193	0	goto err;
194	0	}
195
196	733	if (ctx == NULL) {
197	604	ctx = new_ctx = BN_CTX_new();
198	604	if (ctx == NULL)
199	0	return 0;
200	604	}
201
202	733	BN_CTX_start(ctx);
203	733	used_ctx = 1;
204	733	x = BN_CTX_get(ctx);
205	733	y = BN_CTX_get(ctx);
206	733	if (y == NULL)
207	0	goto err;
208
209	733	if (!EC_POINT_get_affine_coordinates(group, point, x, y, ctx))
210	0	goto err;
211
212	733	if ((form == POINT_CONVERSION_COMPRESSED
213	733	\|\| form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
214	86	buf[0] = form + 1;
215	647	else
216	647	buf[0] = form;
217
218	733	i = 1;
219
220	733	skip = field_len - BN_num_bytes(x);
221	733	if (skip > field_len) {
222	0	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
223	0	goto err;
224	0	}
225	2.04k	while (skip > 0) {
226	1.31k	buf[i++] = 0;
227	1.31k	skip--;
228	1.31k	}
229	733	skip = BN_bn2bin(x, buf + i);
230	733	i += skip;
231	733	if (i != 1 + field_len) {
232	0	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
233	0	goto err;
234	0	}
235
236	733	if (form == POINT_CONVERSION_UNCOMPRESSED
237	733	\|\| form == POINT_CONVERSION_HYBRID) {
238	299	skip = field_len - BN_num_bytes(y);
239	299	if (skip > field_len) {
240	0	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
241	0	goto err;
242	0	}
243	344	while (skip > 0) {
244	45	buf[i++] = 0;
245	45	skip--;
246	45	}
247	299	skip = BN_bn2bin(y, buf + i);
248	299	i += skip;
249	299	}
250
251	733	if (i != ret) {
252	0	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
253	0	goto err;
254	0	}
255	733	}
256
257	1.46k	if (used_ctx)
258	733	BN_CTX_end(ctx);
259	1.46k	BN_CTX_free(new_ctx);
260	1.46k	return ret;
261
262	4	err:
263	4	if (used_ctx)
264	0	BN_CTX_end(ctx);
265	4	BN_CTX_free(new_ctx);
266	4	return 0;
267	1.46k	}
268
269		int ec_GFp_simple_oct2point(const EC_GROUP group, EC_POINT point,
270		const unsigned char buf, size_t len, BN_CTX ctx)
271	10.5k	{
272	10.5k	point_conversion_form_t form;
273	10.5k	int y_bit;
274	10.5k	BN_CTX *new_ctx = NULL;
275	10.5k	BIGNUM x, y;
276	10.5k	size_t field_len, enc_len;
277	10.5k	int ret = 0;
278
279	10.5k	if (len == 0) {
280	263	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
281	263	return 0;
282	263	}
283	10.3k	form = buf[0];
284	10.3k	y_bit = form & 1;
285	10.3k	form = form & ~1U;
286	10.3k	if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
287	10.3k	&& (form != POINT_CONVERSION_UNCOMPRESSED)
288	10.3k	&& (form != POINT_CONVERSION_HYBRID)) {
289	248	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
290	248	return 0;
291	248	}
292	10.0k	if ((form == 0 \|\| form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
293	71	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
294	71	return 0;
295	71	}
296
297	10.0k	if (form == 0) {
298	330	if (len != 1) {
299	122	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
300	122	return 0;
301	122	}
302
303	208	return EC_POINT_set_to_infinity(group, point);
304	330	}
305
306	9.68k	field_len = BN_num_bytes(group->field);
307	9.68k	enc_len =
308	9.68k	(form ==
309	9.68k	POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
310
311	9.68k	if (len != enc_len) {
312	367	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
313	367	return 0;
314	367	}
315
316	9.31k	if (ctx == NULL) {
317	9.31k	ctx = new_ctx = BN_CTX_new();
318	9.31k	if (ctx == NULL)
319	0	return 0;
320	9.31k	}
321
322	9.31k	BN_CTX_start(ctx);
323	9.31k	x = BN_CTX_get(ctx);
324	9.31k	y = BN_CTX_get(ctx);
325	9.31k	if (y == NULL)
326	0	goto err;
327
328	9.31k	if (!BN_bin2bn(buf + 1, field_len, x))
329	0	goto err;
330	9.31k	if (BN_ucmp(x, group->field) >= 0) {
331	78	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
332	78	goto err;
333	78	}
334
335	9.23k	if (form == POINT_CONVERSION_COMPRESSED) {
336	5.89k	if (!EC_POINT_set_compressed_coordinates(group, point, x, y_bit, ctx))
337	2.09k	goto err;
338	5.89k	} else {
339	3.34k	if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
340	0	goto err;
341	3.34k	if (BN_ucmp(y, group->field) >= 0) {
342	66	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
343	66	goto err;
344	66	}
345	3.27k	if (form == POINT_CONVERSION_HYBRID) {
346	138	if (y_bit != BN_is_odd(y)) {
347	66	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
348	66	goto err;
349	66	}
350	138	}
351
352		/*
353		* EC_POINT_set_affine_coordinates is responsible for checking that
354		* the point is on the curve.
355		*/
356	3.21k	if (!EC_POINT_set_affine_coordinates(group, point, x, y, ctx))
357	1.70k	goto err;
358	3.21k	}
359
360	5.30k	ret = 1;
361
362	9.31k	err:
363	9.31k	BN_CTX_end(ctx);
364	9.31k	BN_CTX_free(new_ctx);
365	9.31k	return ret;
366	5.30k	}