--- /dev/null
+/**********************************************************************
+ * 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;
+}
projects / openssl.git / blobdiff