diff options
Diffstat (limited to 'engines/ccgost/gost94_keyx.c')
| -rw-r--r-- | engines/ccgost/gost94_keyx.c | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/engines/ccgost/gost94_keyx.c b/engines/ccgost/gost94_keyx.c new file mode 100644 index 0000000000..4cf8a0ba80 --- /dev/null +++ b/engines/ccgost/gost94_keyx.c @@ -0,0 +1,420 @@ +/********************************************************************** + * gost94_keyx.c * + * Copyright (c) 2005-2006 Cryptocom LTD * + * This file is distributed under the same license as OpenSSL * + * * + * Implements generation and parsing of GOST_KEY_TRANSPORT for * + * GOST R 34.10-94 algorithms * + * * + * Requires OpenSSL 0.9.9 for compilation * + **********************************************************************/ +#include <string.h> +#include <openssl/dh.h> +#include <openssl/rand.h> +#include <openssl/evp.h> +#include <openssl/objects.h> + +#include "gostkeyx.h" +#include "gost_asn1.h" +#include "gost89.h" +#include "gosthash.h" +#include "crypt.h" +#include "e_gost_err.h" +#include "pmeth.h" +#include "keywrap.h" +#include "tools.h" +/* Common functions for both 94 and 2001 key exchange schemes */ +int decrypt_cryptocom_key(unsigned char *sess_key,int max_key_len, + const unsigned char *crypted_key,int crypted_key_len, gost_ctx *ctx) +{ + int i; + int j; + int blocks = crypted_key_len >>3; + unsigned char gamma[8]; + if (max_key_len <crypted_key_len) { + GOSTerr(GOST_F_DECRYPT_CRYPTOCOM_KEY,GOST_R_NOT_ENOUGH_SPACE_FOR_KEY); + return 0; + } + if ((crypted_key_len & 7) !=0) + { + GOSTerr(GOST_F_DECRYPT_CRYPTOCOM_KEY,GOST_R_INVALID_ENCRYPTED_KEY_SIZE); + return 0; + } + for (i=blocks-1;i>0;i--) + { + gostcrypt(ctx,crypted_key+(i-1)*8,gamma); + for(j=0;j<8;j++) + { + sess_key[i*8+j]=gamma[j]^crypted_key[i*8+j]; + } + } + gostcrypt(ctx,sess_key+crypted_key_len-8,gamma); + for(j=0;j<8;j++) + { + sess_key[j]=gamma[j]^crypted_key[j]; + } + return 1; +} +int encrypt_cryptocom_key(const unsigned char *sess_key,int key_len, + unsigned char *crypted_key, gost_ctx *ctx) +{ + int i; + int j; + unsigned char gamma[8]; + memcpy(gamma,sess_key+key_len-8,8); + for (i=0;i<key_len;i+=8) + { + gostcrypt(ctx,gamma,gamma); + for (j=0;j<8;j++) + gamma[j]=crypted_key[i+j]=sess_key[i+j]^gamma[j]; + } + return 1; +} +/* Implementation of the Diffi-Hellman key agreement scheme based on + * GOST-94 keys */ + +/* Computes Diffie-Hellman key and stores it into buffer in + * little-endian byte order as expected by both versions of GOST 94 + * algorigthm + */ +static int compute_pair_key_le(unsigned char *pair_key,BIGNUM *pub_key,DH *dh) +{ + unsigned char be_key[128]; + int i,key_size; + key_size=DH_compute_key(be_key,pub_key,dh); + if (!key_size) return 0; + memset(pair_key,0,128); + for (i=0;i<key_size;i++) { + pair_key[i]=be_key[key_size-1-i]; + } + return key_size; +} +/* + * Computes 256 bit key exchange key for CryptoCom variation of GOST 94 + * algorithm + */ +static int make_gost_shared_key(DH *dh,EVP_PKEY *pubk,unsigned char *shared_key) +{ + unsigned char dh_key [128]; + int i; + /* Compute key */ + memset(dh_key,0,128); + if (!compute_pair_key_le(dh_key,((DSA *)EVP_PKEY_get0(pubk))->pub_key,dh)) return 0; + /* Fold it down to 256 bit */ + /* According to GOST either 2^1020<p<2^1024 or + * 2^509<p<2^512, so DH_size can be exactly 128 or exactly 64 only + */ + + if (DH_size(dh)==128) + for (i=0;i<64;i++) { + dh_key[i]^=dh_key[64+i]; + } + for (i=0;i<32;i++) { + shared_key[i]=dh_key[i]^dh_key[32+i]; + } + return 1; +} + +static DH *make_ephemeral_key(EVP_PKEY *pubk,BIGNUM *ephemeral_key) +{ + DH *dh = DH_new(); + dh->g = BN_dup(pubk->pkey.dsa->g); + dh->p = BN_dup(pubk->pkey.dsa->p); + dh->priv_key = BN_dup(ephemeral_key); + /* Generate ephemeral key pair */ + if (!DH_generate_key(dh)) { + DH_free(dh); + return NULL; + } + return dh; +} +/* + * Computes 256 bit Key exchange key as specified in RFC 4357 + */ +static int make_cp_exchange_key(DH *dh,EVP_PKEY *pubk, unsigned char *shared_key) +{ + unsigned char dh_key [128]; + gost_hash_ctx hash_ctx; + memset(dh_key,0,128); + if (!compute_pair_key_le(dh_key,((DSA *)(EVP_PKEY_get0(pubk)))->pub_key,dh)) return 0; + init_gost_hash_ctx(&hash_ctx,&GostR3411_94_CryptoProParamSet); + start_hash(&hash_ctx); + hash_block(&hash_ctx,dh_key,128); + finish_hash(&hash_ctx,shared_key); + done_gost_hash_ctx(&hash_ctx); + return 1; +} +/* EVP_PKEY_METHOD callback encrypt for + * GOST R 34.10-94 cryptopro modification + */ + +int pkey_GOST94cp_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen, const unsigned char* key, size_t key_len ) +{ + GOST_KEY_TRANSPORT *gkt=NULL; + DH *dh = NULL; + unsigned char shared_key[32], ukm[8],crypted_key[44]; + const struct gost_cipher_info *param=get_encryption_params(NULL); + EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx); + struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx); + int size=-1; + gost_ctx cctx; + + + if (!(data->eph_seckey)) { + GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, + GOST_R_CTX_NOT_INITIALIZED_FOR_ENCRYPT); + return -1; + } + + dh = make_ephemeral_key(pubk,gost_get_priv_key(data->eph_seckey)); + gost_init(&cctx,param->sblock); + make_cp_exchange_key(dh,pubk,shared_key); + if (RAND_bytes(ukm,8)<=0) { + GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, + GOST_R_RANDOM_GENERATOR_FAILURE); + return -1; + } + keyWrapCryptoPro(&cctx,shared_key,ukm,key,crypted_key); + gkt = GOST_KEY_TRANSPORT_new(); + if (!gkt) { + goto memerr; + } + if(!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv, + ukm,8)) { + goto memerr; + } + if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,crypted_key+40,4)) { + goto memerr; + } + if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,crypted_key+8,32)) { + goto memerr; + } + if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,data->eph_seckey)) { + GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_CANNOT_PACK_EPHEMERAL_KEY); + goto err; + } + ASN1_OBJECT_free(gkt->key_agreement_info->cipher); + gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid); + *outlen = i2d_GOST_KEY_TRANSPORT(gkt,&out); + if (!size) { + GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO); + size=-1; + } + GOST_KEY_TRANSPORT_free(gkt); + DH_free(dh); + return 1; +memerr: + GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, + GOST_R_MALLOC_FAILURE); +err: + GOST_KEY_TRANSPORT_free(gkt); + DH_free(dh); + return -1; +} +/* EVP_PKEY_METHOD callback encrypt for + * GOST R 34.10-94 cryptocom modification + */ + +int pkey_GOST94cc_encrypt (EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen, const unsigned char * key,size_t key_len) +{ + EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx); + struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx); + /* create DH structure filling parameters from passed pub_key */ + DH *dh = NULL; + GOST_KEY_TRANSPORT *gkt = NULL; + gost_ctx cctx; + EVP_PKEY *newkey=NULL; + unsigned char shared_key[32],encrypted_key[32],hmac[4], + iv[8]={0,0,0,0,0,0,0,0}; + + if (! data->eph_seckey) { + GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT, + GOST_R_CTX_NOT_INITIALIZED_FOR_ENCRYPT); + return -1; + } + dh = make_ephemeral_key(pubk,gost_get_priv_key(data->eph_seckey)); + if (!dh) goto err; + /* compute shared key */ + if (!make_gost_shared_key(dh,pubk,shared_key)) + { + GOSTerr(GOST_F_PKEY_GOST94CC_ENCRYPT,GOST_R_ERROR_COMPUTING_SHARED_KEY); + goto err; + } + /* encrypt session key */ + gost_init(&cctx, &GostR3411_94_CryptoProParamSet); + gost_key(&cctx,shared_key); + encrypt_cryptocom_key(key,key_len,encrypted_key,&cctx); + /* compute hmac of session key */ + if (!gost_mac(&cctx,32,key,32,hmac)) + { + DH_free(dh); + GOSTerr(GOST_F_PKEY_GOST94CC_ENCRYPT,GOST_R_ERROR_COMPUTING_MAC); + return -1; + } + gkt = GOST_KEY_TRANSPORT_new(); + if (!gkt) + { + DH_free(dh); + GOSTerr(GOST_F_PKEY_GOST94CC_ENCRYPT,GOST_R_NO_MEMORY); + return -1; + } + /* Store IV which is always zero in our case */ + if (!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv,iv,8)) + { + GOSTerr(GOST_F_PKEY_GOST94CC_ENCRYPT,GOST_R_ERROR_STORING_IV); + goto err; + } + if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,hmac,4)) + { + GOSTerr(GOST_F_PKEY_GOST94CC_ENCRYPT,GOST_R_ERROR_STORING_MAC); + goto err; + } + if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,encrypted_key,32)) + { + GOSTerr(GOST_F_PKEY_GOST94CC_ENCRYPT,GOST_R_ERROR_STORING_ENCRYPTED_KEY); + goto err; + } + if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,data->eph_seckey)) { + GOSTerr(GOST_F_PKEY_GOST94CC_ENCRYPT,GOST_R_CANNOT_PACK_EPHEMERAL_KEY); + goto err; + } + ASN1_OBJECT_free(gkt->key_agreement_info->cipher); + gkt->key_agreement_info->cipher = OBJ_nid2obj(NID_id_Gost28147_89_cc); + *outlen = i2d_GOST_KEY_TRANSPORT(gkt,&out); +err: + if (gkt) GOST_KEY_TRANSPORT_free(gkt); + if (dh) DH_free(dh); + if (newkey) EVP_PKEY_free(newkey); + return 1; +} + +/* EVP_PLEY_METHOD callback decrypt for + * GOST R 34.10-94 cryptopro modification + */ +int pkey_GOST94cp_decrypt (EVP_PKEY_CTX *ctx, unsigned char *key, size_t *key_len,const unsigned char *in, size_t in_len) { + DH *dh = DH_new(); + const unsigned char *p = in; + GOST_KEY_TRANSPORT *gkt = NULL; + unsigned char wrappedKey[44]; + unsigned char sharedKey[32]; + gost_ctx cctx; + const struct gost_cipher_info *param=NULL; + EVP_PKEY *eph_key=NULL; + EVP_PKEY *priv= EVP_PKEY_CTX_get0_pkey(ctx); + + if (!key) { + *key_len = 32; + return 1; + } + + dh->g = BN_dup(priv->pkey.dsa->g); + dh->p = BN_dup(priv->pkey.dsa->p); + dh->priv_key = BN_dup(priv->pkey.dsa->priv_key); + gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p, + in_len); + if (!gkt) { + GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO); + DH_free(dh); + return 0; + } + eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key); + param = get_encryption_params(gkt->key_agreement_info->cipher); + gost_init(&cctx,param->sblock); + OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8); + memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8); + OPENSSL_assert(gkt->key_info->encrypted_key->length==32); + memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32); + OPENSSL_assert(gkt->key_info->imit->length==4); + memcpy(wrappedKey+40,gkt->key_info->imit->data,4); + make_cp_exchange_key(dh,eph_key,sharedKey); + if (!keyUnwrapCryptoPro(&cctx,sharedKey,wrappedKey,key)) { + GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT, + GOST_R_ERROR_COMPUTING_SHARED_KEY); + goto err; + } + + EVP_PKEY_free(eph_key); + GOST_KEY_TRANSPORT_free(gkt); + DH_free(dh); + return 1; +err: + EVP_PKEY_free(eph_key); + GOST_KEY_TRANSPORT_free(gkt); + DH_free(dh); + return -1; + +} +/* EVP_PKEY_METHOD callback decrypt for + * GOST R 34.10-94 cryptocom modification + */ + +int pkey_GOST94cc_decrypt (EVP_PKEY_CTX *pctx, unsigned char *key, size_t *key_len, const unsigned char *in, size_t in_len) +{ + /* Form DH params from compute shared key */ + GOST_KEY_TRANSPORT *gkt = NULL; + const unsigned char *p=in; + unsigned char shared_key[32]; + unsigned char hmac[4],hmac_comp[4]; + unsigned char iv[8]; + int i; + gost_ctx ctx; + DH *dh = DH_new(); + EVP_PKEY *eph_key; + EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(pctx); + + if (!key) { + *key_len = 32; + return 1; + } + /* Construct DH structure from the our GOST private key */ + dh->g = BN_dup(priv->pkey.dsa->g); + dh->p = BN_dup(priv->pkey.dsa->p); + dh->priv_key = BN_dup(priv->pkey.dsa->priv_key); + /* Parse passed octet string and find out public key, iv and HMAC*/ + gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p, + in_len); + if (!gkt) { + GOSTerr(GOST_F_PKEY_GOST94CC_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO); + DH_free(dh); + return 0; + } + eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key); + /* Initialization vector is really ignored here */ + OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8); + memcpy(iv,gkt->key_agreement_info->eph_iv->data,8); + /* HMAC should be computed and checked */ + OPENSSL_assert(gkt->key_info->imit->length==4); + memcpy(hmac,gkt->key_info->imit->data,4); + /* Compute shared key */ + i=make_gost_shared_key(dh,eph_key,shared_key); + EVP_PKEY_free(eph_key); + DH_free(dh); + if (!i) + { + GOSTerr(GOST_F_PKEY_GOST94CC_DECRYPT,GOST_R_ERROR_COMPUTING_SHARED_KEY); + GOST_KEY_TRANSPORT_free(gkt); + return 0; + } + /* Decrypt session key */ + gost_init(&ctx, &GostR3411_94_CryptoProParamSet); + gost_key(&ctx,shared_key); + + if (!decrypt_cryptocom_key(key,*key_len,gkt->key_info->encrypted_key->data, + gkt->key_info->encrypted_key->length, &ctx)) + { + GOST_KEY_TRANSPORT_free(gkt); + return 0; + } + GOST_KEY_TRANSPORT_free(gkt); + /* check HMAC of session key*/ + if (!gost_mac(&ctx,32,key,32,hmac_comp)) { + GOSTerr(GOST_F_PKEY_GOST94CC_DECRYPT,GOST_R_ERROR_COMPUTING_MAC); + return 0; + } + /* HMAC of session key is not correct */ + if (memcmp(hmac,hmac_comp,4)!=0) { + GOSTerr(GOST_F_PKEY_GOST94CC_DECRYPT,GOST_R_SESSION_KEY_MAC_DOES_NOT_MATCH); + return 0; + } + return 1; +} |