/src/mbedtls/3rdparty/everest/library/x25519.c

Source
/*
 *  ECDH with curve-optimized implementation multiplexing
 *
 *  Copyright 2016-2018 INRIA and Microsoft Corporation
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of Mbed TLS (https://tls.mbed.org)
 */

#include "common.h"

#if defined(MBEDTLS_ECDH_C) && defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED)

#include <mbedtls/ecdh.h>

#if !(defined(__SIZEOF_INT128__) && (__SIZEOF_INT128__ == 16))
#define KRML_VERIFIED_UINT128
#endif

#include <Hacl_Curve25519.h>
#include <mbedtls/platform_util.h>

#include "x25519.h"

#include <string.h>

/*
 * Initialize context
 */
void mbedtls_x25519_init( mbedtls_x25519_context *ctx )
{
    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x25519_context ) );
}

/*
 * Free context
 */
void mbedtls_x25519_free( mbedtls_x25519_context *ctx )
{
    if( ctx == NULL )
        return;

    mbedtls_platform_zeroize( ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES );
    mbedtls_platform_zeroize( ctx->peer_point, MBEDTLS_X25519_KEY_SIZE_BYTES );
}

int mbedtls_x25519_make_params( mbedtls_x25519_context *ctx, size_t *olen,
                        unsigned char *buf, size_t blen,
                        int( *f_rng )(void *, unsigned char *, size_t),
                        void *p_rng )
{
    int ret = 0;

    uint8_t base[MBEDTLS_X25519_KEY_SIZE_BYTES] = {0};

    if( ( ret = f_rng( p_rng, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES ) ) != 0 )
        return ret;

    *olen = MBEDTLS_X25519_KEY_SIZE_BYTES + 4;
    if( blen < *olen )
        return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

    *buf++ = MBEDTLS_ECP_TLS_NAMED_CURVE;
    *buf++ = MBEDTLS_ECP_TLS_CURVE25519 >> 8;
    *buf++ = MBEDTLS_ECP_TLS_CURVE25519 & 0xFF;
    *buf++ = MBEDTLS_X25519_KEY_SIZE_BYTES;

    base[0] = 9;
    Hacl_Curve25519_crypto_scalarmult( buf, ctx->our_secret, base );

    base[0] = 0;
    if( memcmp( buf, base, MBEDTLS_X25519_KEY_SIZE_BYTES) == 0 )
        return MBEDTLS_ERR_ECP_RANDOM_FAILED;

    return( 0 );
}

int mbedtls_x25519_read_params( mbedtls_x25519_context *ctx,
                        const unsigned char **buf, const unsigned char *end )
{
    if( end - *buf < MBEDTLS_X25519_KEY_SIZE_BYTES + 1 )
        return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

    if( ( *(*buf)++ != MBEDTLS_X25519_KEY_SIZE_BYTES ) )
        return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

    memcpy( ctx->peer_point, *buf, MBEDTLS_X25519_KEY_SIZE_BYTES );
    *buf += MBEDTLS_X25519_KEY_SIZE_BYTES;
    return( 0 );
}

int mbedtls_x25519_get_params( mbedtls_x25519_context *ctx, const mbedtls_ecp_keypair *key,
                               mbedtls_x25519_ecdh_side side )
{
    size_t olen = 0;

    switch( side ) {
    case MBEDTLS_X25519_ECDH_THEIRS:
        return mbedtls_ecp_point_write_binary( &key->grp, &key->Q, MBEDTLS_ECP_PF_COMPRESSED, &olen, ctx->peer_point, MBEDTLS_X25519_KEY_SIZE_BYTES );
    case MBEDTLS_X25519_ECDH_OURS:
        return mbedtls_mpi_write_binary_le( &key->d, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES );
    default:
        return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
    }
}

int mbedtls_x25519_calc_secret( mbedtls_x25519_context *ctx, size_t *olen,
                        unsigned char *buf, size_t blen,
                        int( *f_rng )(void *, unsigned char *, size_t),
                        void *p_rng )
{
    /* f_rng and p_rng are not used here because this implementation does not
       need blinding since it has constant trace. */
    (( void )f_rng);
    (( void )p_rng);

    *olen = MBEDTLS_X25519_KEY_SIZE_BYTES;

    if( blen < *olen )
        return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

    /* scalarmult modifies this input, let's make a copy... */
    unsigned char secret[MBEDTLS_X25519_KEY_SIZE_BYTES];
    memcpy(secret, ctx->our_secret, sizeof(secret));

    Hacl_Curve25519_crypto_scalarmult( buf, secret, ctx->peer_point);

    /* Wipe the copy and don't let the peer choose a small subgroup point */
    mbedtls_platform_zeroize( secret, MBEDTLS_X25519_KEY_SIZE_BYTES );

    if( memcmp( buf, secret, MBEDTLS_X25519_KEY_SIZE_BYTES) == 0 )
        return MBEDTLS_ERR_ECP_RANDOM_FAILED;

    return( 0 );
}

int mbedtls_x25519_make_public( mbedtls_x25519_context *ctx, size_t *olen,
                        unsigned char *buf, size_t blen,
                        int( *f_rng )(void *, unsigned char *, size_t),
                        void *p_rng )
{
    int ret = 0;
    unsigned char base[MBEDTLS_X25519_KEY_SIZE_BYTES] = { 0 };

    if( ctx == NULL )
        return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

    if( ( ret = f_rng( p_rng, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES ) ) != 0 )
        return ret;

    *olen = MBEDTLS_X25519_KEY_SIZE_BYTES + 1;
    if( blen < *olen )
        return(MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL);
    *buf++ = MBEDTLS_X25519_KEY_SIZE_BYTES;

    base[0] = 9;
    Hacl_Curve25519_crypto_scalarmult( buf, ctx->our_secret, base );

    base[0] = 0;
    if( memcmp( buf, base, MBEDTLS_X25519_KEY_SIZE_BYTES ) == 0 )
        return MBEDTLS_ERR_ECP_RANDOM_FAILED;

    return( ret );
}

int mbedtls_x25519_read_public( mbedtls_x25519_context *ctx,
                        const unsigned char *buf, size_t blen )
{
    if( blen < MBEDTLS_X25519_KEY_SIZE_BYTES + 1 )
        return(MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL);
    if( (*buf++ != MBEDTLS_X25519_KEY_SIZE_BYTES) )
        return(MBEDTLS_ERR_ECP_BAD_INPUT_DATA);
    memcpy( ctx->peer_point, buf, MBEDTLS_X25519_KEY_SIZE_BYTES );
    return( 0 );
}


#endif /* MBEDTLS_ECDH_C && MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED */

Line	Count	Source
1		/*
2		* ECDH with curve-optimized implementation multiplexing
3		*
4		* Copyright 2016-2018 INRIA and Microsoft Corporation
5		* SPDX-License-Identifier: Apache-2.0
6		*
7		* Licensed under the Apache License, Version 2.0 (the "License"); you may
8		* not use this file except in compliance with the License.
9		* You may obtain a copy of the License at
10		*
11		* http://www.apache.org/licenses/LICENSE-2.0
12		*
13		* Unless required by applicable law or agreed to in writing, software
14		* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15		* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16		* See the License for the specific language governing permissions and
17		* limitations under the License.
18		*
19		* This file is part of Mbed TLS (https://tls.mbed.org)
20		*/
21
22		#include "common.h"
23
24		#if defined(MBEDTLS_ECDH_C) && defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED)
25
26		#include <mbedtls/ecdh.h>
27
28		#if !(defined(__SIZEOF_INT128__) && (__SIZEOF_INT128__ == 16))
29		#define KRML_VERIFIED_UINT128
30		#endif
31
32		#include <Hacl_Curve25519.h>
33		#include <mbedtls/platform_util.h>
34
35		#include "x25519.h"
36
37		#include <string.h>
38
39		/*
40		* Initialize context
41		*/
42		void mbedtls_x25519_init( mbedtls_x25519_context *ctx )
43	0	{
44	0	mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x25519_context ) );
45	0	}
46
47		/*
48		* Free context
49		*/
50		void mbedtls_x25519_free( mbedtls_x25519_context *ctx )
51	0	{
52	0	if( ctx == NULL )
53	0	return;
54
55	0	mbedtls_platform_zeroize( ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES );
56	0	mbedtls_platform_zeroize( ctx->peer_point, MBEDTLS_X25519_KEY_SIZE_BYTES );
57	0	}
58
59		int mbedtls_x25519_make_params( mbedtls_x25519_context ctx, size_t olen,
60		unsigned char *buf, size_t blen,
61		int( f_rng )(void , unsigned char *, size_t),
62		void *p_rng )
63	0	{
64	0	int ret = 0;
65
66	0	uint8_t base[MBEDTLS_X25519_KEY_SIZE_BYTES] = {0};
67
68	0	if( ( ret = f_rng( p_rng, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES ) ) != 0 )
69	0	return ret;
70
71	0	*olen = MBEDTLS_X25519_KEY_SIZE_BYTES + 4;
72	0	if( blen < *olen )
73	0	return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
74
75	0	*buf++ = MBEDTLS_ECP_TLS_NAMED_CURVE;
76	0	*buf++ = MBEDTLS_ECP_TLS_CURVE25519 >> 8;
77	0	*buf++ = MBEDTLS_ECP_TLS_CURVE25519 & 0xFF;
78	0	*buf++ = MBEDTLS_X25519_KEY_SIZE_BYTES;
79
80	0	base[0] = 9;
81	0	Hacl_Curve25519_crypto_scalarmult( buf, ctx->our_secret, base );
82
83	0	base[0] = 0;
84	0	if( memcmp( buf, base, MBEDTLS_X25519_KEY_SIZE_BYTES) == 0 )
85	0	return MBEDTLS_ERR_ECP_RANDOM_FAILED;
86
87	0	return( 0 );
88	0	}
89
90		int mbedtls_x25519_read_params( mbedtls_x25519_context *ctx,
91		const unsigned char *buf, const unsigned char end )
92	0	{
93	0	if( end - *buf < MBEDTLS_X25519_KEY_SIZE_BYTES + 1 )
94	0	return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
95
96	0	if( ( (buf)++ != MBEDTLS_X25519_KEY_SIZE_BYTES ) )
97	0	return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
98
99	0	memcpy( ctx->peer_point, *buf, MBEDTLS_X25519_KEY_SIZE_BYTES );
100	0	*buf += MBEDTLS_X25519_KEY_SIZE_BYTES;
101	0	return( 0 );
102	0	}
103
104		int mbedtls_x25519_get_params( mbedtls_x25519_context ctx, const mbedtls_ecp_keypair key,
105		mbedtls_x25519_ecdh_side side )
106	0	{
107	0	size_t olen = 0;
108
109	0	switch( side ) {
110	0	case MBEDTLS_X25519_ECDH_THEIRS:
111	0	return mbedtls_ecp_point_write_binary( &key->grp, &key->Q, MBEDTLS_ECP_PF_COMPRESSED, &olen, ctx->peer_point, MBEDTLS_X25519_KEY_SIZE_BYTES );
112	0	case MBEDTLS_X25519_ECDH_OURS:
113	0	return mbedtls_mpi_write_binary_le( &key->d, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES );
114	0	default:
115	0	return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
116	0	}
117	0	}
118
119		int mbedtls_x25519_calc_secret( mbedtls_x25519_context ctx, size_t olen,
120		unsigned char *buf, size_t blen,
121		int( f_rng )(void , unsigned char *, size_t),
122		void *p_rng )
123	0	{
124		/* f_rng and p_rng are not used here because this implementation does not
125		need blinding since it has constant trace. */
126	0	(( void )f_rng);
127	0	(( void )p_rng);
128
129	0	*olen = MBEDTLS_X25519_KEY_SIZE_BYTES;
130
131	0	if( blen < *olen )
132	0	return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
133
134		/* scalarmult modifies this input, let's make a copy... */
135	0	unsigned char secret[MBEDTLS_X25519_KEY_SIZE_BYTES];
136	0	memcpy(secret, ctx->our_secret, sizeof(secret));
137
138	0	Hacl_Curve25519_crypto_scalarmult( buf, secret, ctx->peer_point);
139
140		/* Wipe the copy and don't let the peer choose a small subgroup point */
141	0	mbedtls_platform_zeroize( secret, MBEDTLS_X25519_KEY_SIZE_BYTES );
142
143	0	if( memcmp( buf, secret, MBEDTLS_X25519_KEY_SIZE_BYTES) == 0 )
144	0	return MBEDTLS_ERR_ECP_RANDOM_FAILED;
145
146	0	return( 0 );
147	0	}
148
149		int mbedtls_x25519_make_public( mbedtls_x25519_context ctx, size_t olen,
150		unsigned char *buf, size_t blen,
151		int( f_rng )(void , unsigned char *, size_t),
152		void *p_rng )
153	0	{
154	0	int ret = 0;
155	0	unsigned char base[MBEDTLS_X25519_KEY_SIZE_BYTES] = { 0 };
156
157	0	if( ctx == NULL )
158	0	return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
159
160	0	if( ( ret = f_rng( p_rng, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES ) ) != 0 )
161	0	return ret;
162
163	0	*olen = MBEDTLS_X25519_KEY_SIZE_BYTES + 1;
164	0	if( blen < *olen )
165	0	return(MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL);
166	0	*buf++ = MBEDTLS_X25519_KEY_SIZE_BYTES;
167
168	0	base[0] = 9;
169	0	Hacl_Curve25519_crypto_scalarmult( buf, ctx->our_secret, base );
170
171	0	base[0] = 0;
172	0	if( memcmp( buf, base, MBEDTLS_X25519_KEY_SIZE_BYTES ) == 0 )
173	0	return MBEDTLS_ERR_ECP_RANDOM_FAILED;
174
175	0	return( ret );
176	0	}
177
178		int mbedtls_x25519_read_public( mbedtls_x25519_context *ctx,
179		const unsigned char *buf, size_t blen )
180	0	{
181	0	if( blen < MBEDTLS_X25519_KEY_SIZE_BYTES + 1 )
182	0	return(MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL);
183	0	if( (*buf++ != MBEDTLS_X25519_KEY_SIZE_BYTES) )
184	0	return(MBEDTLS_ERR_ECP_BAD_INPUT_DATA);
185	0	memcpy( ctx->peer_point, buf, MBEDTLS_X25519_KEY_SIZE_BYTES );
186	0	return( 0 );
187	0	}
188
189
190		#endif /* MBEDTLS_ECDH_C && MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED */

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Created: 2026-07-25 06:10