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Annotation of embedaddon/strongswan/src/libstrongswan/plugins/curve25519/curve25519_dh.c, revision 1.1.1.1

1.1       misho       1: /*
                      2:  * Copyright (C) 2015 Martin Willi
                      3:  * Copyright (C) 2015 revosec AG
                      4:  *
                      5:  * This program is free software; you can redistribute it and/or modify it
                      6:  * under the terms of the GNU General Public License as published by the
                      7:  * Free Software Foundation; either version 2 of the License, or (at your
                      8:  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
                      9:  *
                     10:  * This program is distributed in the hope that it will be useful, but
                     11:  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     12:  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
                     13:  * for more details.
                     14:  */
                     15: 
                     16: #include <string.h>
                     17: #include <stdint.h>
                     18: 
                     19: #include "curve25519_dh.h"
                     20: #include "curve25519_drv.h"
                     21: 
                     22: typedef struct private_curve25519_dh_t private_curve25519_dh_t;
                     23: 
                     24: /**
                     25:  * Private data of an curve25519_dh_t object.
                     26:  */
                     27: struct private_curve25519_dh_t {
                     28: 
                     29:        /**
                     30:         * Public curve25519_dh_t interface.
                     31:         */
                     32:        curve25519_dh_t public;
                     33: 
                     34:        /**
                     35:         * Shared key, if computed
                     36:         */
                     37:        u_char shared[CURVE25519_KEY_SIZE];
                     38: 
                     39:        /**
                     40:         * TRUE if shared secret is computed
                     41:         */
                     42:        bool computed;
                     43: 
                     44:        /**
                     45:         * Curve25519 backend
                     46:         */
                     47:        curve25519_drv_t *drv;
                     48: };
                     49: 
                     50: /**
                     51:  * Generate a valid Curve25519 key
                     52:  */
                     53: static bool generate_key(private_curve25519_dh_t *this)
                     54: {
                     55:        u_char key[CURVE25519_KEY_SIZE];
                     56:        rng_t *rng;
                     57: 
                     58:        rng = lib->crypto->create_rng(lib->crypto, RNG_STRONG);
                     59:        if (!rng)
                     60:        {
                     61:                DBG1(DBG_LIB, "no RNG found for quality %N",
                     62:                         rng_quality_names, RNG_STRONG);
                     63:                return FALSE;
                     64:        }
                     65:        if (!rng->get_bytes(rng, CURVE25519_KEY_SIZE, key))
                     66:        {
                     67:                rng->destroy(rng);
                     68:                return FALSE;
                     69:        }
                     70:        rng->destroy(rng);
                     71: 
                     72:        return this->drv->set_key(this->drv, key);
                     73: }
                     74: 
                     75: METHOD(diffie_hellman_t, set_other_public_value, bool,
                     76:        private_curve25519_dh_t *this, chunk_t value)
                     77: {
                     78:        if (value.len == CURVE25519_KEY_SIZE)
                     79:        {
                     80:                if (this->drv->curve25519(this->drv, value.ptr, this->shared))
                     81:                {
                     82:                        this->computed = TRUE;
                     83:                        return TRUE;
                     84:                }
                     85:        }
                     86:        return FALSE;
                     87: }
                     88: 
                     89: METHOD(diffie_hellman_t, get_my_public_value, bool,
                     90:        private_curve25519_dh_t *this, chunk_t *value)
                     91: {
                     92:        u_char basepoint[CURVE25519_KEY_SIZE] = { 9 };
                     93: 
                     94:        *value = chunk_alloc(CURVE25519_KEY_SIZE);
                     95:        if (this->drv->curve25519(this->drv, basepoint, value->ptr))
                     96:        {
                     97:                return TRUE;
                     98:        }
                     99:        free(value->ptr);
                    100:        return FALSE;
                    101: }
                    102: 
                    103: METHOD(diffie_hellman_t, set_private_value, bool,
                    104:        private_curve25519_dh_t *this, chunk_t value)
                    105: {
                    106:        if (value.len != CURVE25519_KEY_SIZE)
                    107:        {
                    108:                return FALSE;
                    109:        }
                    110:        return this->drv->set_key(this->drv, value.ptr);
                    111: }
                    112: 
                    113: METHOD(diffie_hellman_t, get_shared_secret, bool,
                    114:        private_curve25519_dh_t *this, chunk_t *secret)
                    115: {
                    116:        if (!this->computed)
                    117:        {
                    118:                return FALSE;
                    119:        }
                    120:        *secret = chunk_clone(chunk_from_thing(this->shared));
                    121:        return TRUE;
                    122: }
                    123: 
                    124: METHOD(diffie_hellman_t, get_dh_group, diffie_hellman_group_t,
                    125:        private_curve25519_dh_t *this)
                    126: {
                    127:        return CURVE_25519;
                    128: }
                    129: 
                    130: METHOD(diffie_hellman_t, destroy, void,
                    131:        private_curve25519_dh_t *this)
                    132: {
                    133:        this->drv->destroy(this->drv);
                    134:        free(this);
                    135: }
                    136: 
                    137: /*
                    138:  * Described in header.
                    139:  */
                    140: curve25519_dh_t *curve25519_dh_create(diffie_hellman_group_t group)
                    141: {
                    142:        private_curve25519_dh_t *this;
                    143: 
                    144:        if (group != CURVE_25519)
                    145:        {
                    146:                return FALSE;
                    147:        }
                    148: 
                    149:        INIT(this,
                    150:                .public = {
                    151:                        .dh = {
                    152:                                .get_shared_secret = _get_shared_secret,
                    153:                                .set_other_public_value = _set_other_public_value,
                    154:                                .get_my_public_value = _get_my_public_value,
                    155:                                .set_private_value = _set_private_value,
                    156:                                .get_dh_group = _get_dh_group,
                    157:                                .destroy = _destroy,
                    158:                        },
                    159:                },
                    160:                .drv = curve25519_drv_probe(),
                    161:        );
                    162: 
                    163:        if (!this->drv)
                    164:        {
                    165:                free(this);
                    166:                return NULL;
                    167:        }
                    168:        if (!generate_key(this))
                    169:        {
                    170:                destroy(this);
                    171:                return NULL;
                    172:        }
                    173:        return &this->public;
                    174: }