GOST key transport 2018 - decrypt as separate function

diff --git a/e_gost_err.c b/e_gost_err.c
index d3008d265bfb2dae1b5241901b9c5ee22e6d3ab3..0bc085642587f3698c12bef38824a168e4148cc8 100644 (file)
--- a/e_gost_err.c
+++ b/e_gost_err.c
@@ -50,8 +50,7 @@ static ERR_STRING_DATA GOST_str_functs[] = {
     {ERR_PACK(0, GOST_F_PARAM_COPY_GOST_EC, 0), "param_copy_gost_ec"},
     {ERR_PACK(0, GOST_F_PKEY_GOST2001_PARAMGEN, 0), "pkey_gost2001_paramgen"},
     {ERR_PACK(0, GOST_F_PKEY_GOST2012_PARAMGEN, 0), "pkey_gost2012_paramgen"},
-    {ERR_PACK(0, GOST_F_PKEY_GOST2018_ECCP_ENCRYPT, 0),
-     "pkey_gost2018_encrypt"},
+    {ERR_PACK(0, GOST_F_PKEY_GOST2018_DECRYPT, 0), "pkey_gost2018_decrypt"},
     {ERR_PACK(0, GOST_F_PKEY_GOST2018_ENCRYPT, 0), "pkey_gost2018_encrypt"},
     {ERR_PACK(0, GOST_F_PKEY_GOST_CTRL, 0), "pkey_gost_ctrl"},
     {ERR_PACK(0, GOST_F_PKEY_GOST_ECCP_DECRYPT, 0), "pkey_GOST_ECcp_decrypt"},

diff --git a/e_gost_err.h b/e_gost_err.h
index 2b1d8bab4d79610cb927a7e8f056872367cd5d75..90c3b4139f9f782e1706ec720572c74fe72aa8c0 100644 (file)
--- a/e_gost_err.h
+++ b/e_gost_err.h
@@ -57,7 +57,7 @@ void ERR_GOST_error(int function, int reason, char *file, int line);
 # define GOST_F_PARAM_COPY_GOST_EC                        119
 # define GOST_F_PKEY_GOST2001_PARAMGEN                    120
 # define GOST_F_PKEY_GOST2012_PARAMGEN                    121
-# define GOST_F_PKEY_GOST2018_ECCP_ENCRYPT                150
+# define GOST_F_PKEY_GOST2018_DECRYPT                     150
 # define GOST_F_PKEY_GOST2018_ENCRYPT                     151
 # define GOST_F_PKEY_GOST_CTRL                            122
 # define GOST_F_PKEY_GOST_ECCP_DECRYPT                    123

diff --git a/gost.txt b/gost.txt
index 3f3ffcd3c85e714d9dc717c4597d9267c1b6c260..540b755cab293cffe442c595f2dae04cd3f52a63 100644 (file)
--- a/gost.txt
+++ b/gost.txt
@@ -37,6 +37,8 @@ GOST_F_OMAC_KEY:138:omac_key
 GOST_F_PARAM_COPY_GOST_EC:119:param_copy_gost_ec
 GOST_F_PKEY_GOST2001_PARAMGEN:120:pkey_gost2001_paramgen
 GOST_F_PKEY_GOST2012_PARAMGEN:121:pkey_gost2012_paramgen
+GOST_F_PKEY_GOST2018_DECRYPT:150:pkey_gost2018_decrypt
+GOST_F_PKEY_GOST2018_ENCRYPT:151:pkey_gost2018_encrypt
 GOST_F_PKEY_GOST_CTRL:122:pkey_gost_ctrl
 GOST_F_PKEY_GOST_ECCP_DECRYPT:123:pkey_GOST_ECcp_decrypt
 GOST_F_PKEY_GOST_ECCP_ENCRYPT:124:pkey_GOST_ECcp_encrypt
@@ -67,6 +69,7 @@ GOST_R_BAD_PKEY_PARAMETERS_FORMAT:101:bad pkey parameters format
 GOST_R_CANNOT_PACK_EPHEMERAL_KEY:102:cannot pack ephemeral key
 GOST_R_CIPHER_NOT_FOUND:103:cipher not found
 GOST_R_CTRL_CALL_FAILED:104:ctrl call failed
+GOST_R_ERROR_COMPUTING_EXPORT_KEYS:135:error computing export keys
 GOST_R_ERROR_COMPUTING_SHARED_KEY:105:error computing shared key
 GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO:106:error parsing key transport info
 GOST_R_ERROR_POINT_MUL:107:error point mul

diff --git a/gost_ec_keyx.c b/gost_ec_keyx.c
index 878698f90ff18555be32e51d4dcf956474429c51..1e17f8356030e6d26b04e3f78bc611e53a42b196 100644 (file)
--- a/gost_ec_keyx.c
+++ b/gost_ec_keyx.c
@@ -342,6 +342,10 @@ int pkey_GOST_ECcp_encrypt(EVP_PKEY_CTX *pctx, unsigned char *out,
     return -1;
 }
 
+/*
+ * EVP_PKEY_METHOD callback decrypt
+ * Implementation of GOST2018 key transport
+ */
 int pkey_gost2018_encrypt(EVP_PKEY_CTX *pctx, unsigned char *out,
                           size_t *out_len, const unsigned char *key,
                           size_t key_len)
@@ -355,17 +359,19 @@ int pkey_gost2018_encrypt(EVP_PKEY_CTX *pctx, unsigned char *out,
     int ret = 0;
     int mac_nid = NID_undef;
     size_t mac_len = 0;
-    int exp_len = 0;
+    int exp_len = 0, iv_len = 0;
     unsigned char *exp_buf = NULL;
 
     switch (data->cipher_nid) {
     case NID_magma_ctr:
         mac_nid = NID_magma_mac;
         mac_len = 8;
+        iv_len = 4;
         break;
     case NID_grasshopper_ctr:
         mac_nid = NID_grasshopper_mac;
         mac_len = 16;
+        iv_len = 8;
         break;
     default:
         GOSTerr(GOST_F_PKEY_GOST2018_ENCRYPT, GOST_R_INVALID_CIPHER);
@@ -379,30 +385,26 @@ int pkey_gost2018_encrypt(EVP_PKEY_CTX *pctx, unsigned char *out,
         return -1;
     }
 
-    if (out) {
-        sec_key = EVP_PKEY_new();
-        if (!EVP_PKEY_assign(sec_key, EVP_PKEY_base_id(pubk), EC_KEY_new())
-            || !EVP_PKEY_copy_parameters(sec_key, pubk)
-            || !gost_ec_keygen(EVP_PKEY_get0(sec_key))) {
-            GOSTerr(GOST_F_PKEY_GOST2018_ENCRYPT,
-                    GOST_R_ERROR_COMPUTING_SHARED_KEY);
-            goto err;
-        }
+    sec_key = EVP_PKEY_new();
+    if (!EVP_PKEY_assign(sec_key, EVP_PKEY_base_id(pubk), EC_KEY_new())
+        || !EVP_PKEY_copy_parameters(sec_key, pubk)
+        || !gost_ec_keygen(EVP_PKEY_get0(sec_key))) {
+        GOSTerr(GOST_F_PKEY_GOST2018_ENCRYPT,
+                GOST_R_ERROR_COMPUTING_SHARED_KEY);
+        goto err;
     }
-    ret =
-        gost_keg(data->shared_ukm, pkey_nid,
+
+    if (gost_keg(data->shared_ukm, pkey_nid,
                  EC_KEY_get0_public_key(EVP_PKEY_get0(pubk)),
-                 EVP_PKEY_get0(sec_key), expkeys);
-    if (ret <= 0) {
+                 EVP_PKEY_get0(sec_key), expkeys) <= 0) {
         GOSTerr(GOST_F_PKEY_GOST2018_ENCRYPT,
                 GOST_R_ERROR_COMPUTING_EXPORT_KEYS);
         goto err;
     }
 
-    ret = gost_kexp15(key, key_len, data->cipher_nid, expkeys + 32,
-                      mac_nid, expkeys + 0, data->shared_ukm + 24, 4, exp_buf,
-                      &exp_len);
-    if (ret <= 0) {
+    if (gost_kexp15(key, key_len, data->cipher_nid, expkeys + 32,
+                    mac_nid, expkeys + 0, data->shared_ukm + 24, iv_len,
+                    exp_buf, &exp_len) <= 0) {
         GOSTerr(GOST_F_PKEY_GOST2018_ENCRYPT, GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
         goto err;
     }
@@ -435,7 +437,7 @@ int pkey_gost2018_encrypt(EVP_PKEY_CTX *pctx, unsigned char *out,
 
 /*
  * EVP_PKEY_METHOD callback decrypt
- * Implementation of GOST2001 key transport, cryptopro variation
+ * Implementation of GOST2001/12 key transport, cryptopro variation
  */
 int pkey_GOST_ECcp_decrypt(EVP_PKEY_CTX *pctx, unsigned char *key,
                            size_t *key_len, const unsigned char *in,
@@ -521,3 +523,73 @@ int pkey_GOST_ECcp_decrypt(EVP_PKEY_CTX *pctx, unsigned char *key,
     GOST_KEY_TRANSPORT_free(gkt);
     return ret;
 }
+
+/*
+ * EVP_PKEY_METHOD callback decrypt
+ * Implementation of GOST2018 key transport
+ */
+int pkey_gost2018_decrypt(EVP_PKEY_CTX *pctx, unsigned char *key,
+                          size_t *key_len, const unsigned char *in,
+                          size_t in_len)
+{
+    const unsigned char *p = in;
+    struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(pctx);
+    EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(pctx);
+    PSKeyTransport_gost *pst = NULL;
+    int ret = 0;
+    unsigned char expkeys[64];
+    EVP_PKEY *eph_key = NULL;
+    int pkey_nid = EVP_PKEY_base_id(eph_key);
+    int mac_nid = NID_undef;
+    int iv_len = 0;
+
+    switch (data->cipher_nid) {
+    case NID_magma_ctr:
+        mac_nid = NID_magma_mac;
+        iv_len = 4;
+        break;
+    case NID_grasshopper_ctr:
+        mac_nid = NID_grasshopper_mac;
+        iv_len = 8;
+        break;
+    default:
+        GOSTerr(GOST_F_PKEY_GOST2018_DECRYPT, GOST_R_INVALID_CIPHER);
+        return -1;
+        break;
+    }
+    if (!key) {
+        *key_len = 32;
+        return 1;
+    }
+
+    pst = d2i_PSKeyTransport_gost(NULL, (const unsigned char **)&p, in_len);
+    if (!pst) {
+        GOSTerr(GOST_F_PKEY_GOST2018_DECRYPT,
+                GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
+        return -1;
+    }
+
+    eph_key = X509_PUBKEY_get(pst->ephem_key);
+
+    if (gost_keg(data->shared_ukm, pkey_nid,
+                 EC_KEY_get0_public_key(EVP_PKEY_get0(eph_key)),
+                 EVP_PKEY_get0(priv), expkeys) <= 0) {
+        GOSTerr(GOST_F_PKEY_GOST2018_DECRYPT,
+                GOST_R_ERROR_COMPUTING_EXPORT_KEYS);
+        goto err;
+    }
+
+    if (gost_kimp15(ASN1_STRING_get0_data(pst->psexp),
+                    ASN1_STRING_length(pst->psexp), data->cipher_nid,
+                    expkeys + 32, mac_nid, expkeys + 0, data->shared_ukm + 24,
+                    iv_len, key) <= 0) {
+        GOSTerr(GOST_F_PKEY_GOST2018_DECRYPT, GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
+        goto err;
+    }
+
+    ret = 1;
+ err:
+    EVP_PKEY_free(eph_key);
+    PSKeyTransport_gost_free(pst);
+    return ret;
+}

diff --git a/gost_keyexpimp.c b/gost_keyexpimp.c
index bfdefbcaf515f2df9aa09d4100f1470ec69d0a63..5bd3b4abf95b0fcb39e50b0ed68a1017a21cab26 100644 (file)
--- a/gost_keyexpimp.c
+++ b/gost_keyexpimp.c
@@ -82,14 +82,18 @@ int gost_kexp15(const unsigned char *shared_key, const int shared_len,
     return ret;
 }
 
+/*
+ * Function expects that shared_key is a preallocated 32-bytes buffer
+ * */
 int gost_kimp15(const unsigned char *expkey, const size_t expkeylen,
                 int cipher_nid, const unsigned char *cipher_key,
                 int mac_nid, unsigned char *mac_key,
                 const unsigned char *iv, const size_t ivlen,
-                unsigned char *shared_key, size_t shared_len)
+                unsigned char *shared_key)
 {
     unsigned char iv_full[16], out[48], mac_buf[16];
     unsigned int mac_len;
+    const size_t shared_len = 32;
 
     EVP_CIPHER_CTX *ciph = NULL;
     EVP_MD_CTX *mac = NULL;
@@ -312,7 +316,7 @@ int main(void)
 
     ret = gost_kimp15(magma_export, 40,
                       NID_magma_ctr, magma_key,
-                      NID_magma_mac, mac_magma_key, magma_iv, 4, buf, 32);
+                      NID_magma_mac, mac_magma_key, magma_iv, 4, buf);
 
     if (ret <= 0)
         ERR_print_errors_fp(stderr);

diff --git a/gost_lcl.h b/gost_lcl.h
index a6b6e1224845a3bb14ac29735d412657817ee487..9b0fa1c1dcbabcb96b73ee5ced3528c25412fd98 100644 (file)
--- a/gost_lcl.h
+++ b/gost_lcl.h
@@ -282,7 +282,7 @@ int gost_kimp15(const unsigned char *expkey, const size_t expkeylen,
                 int cipher_nid, const unsigned char *cipher_key,
                 int mac_nid, unsigned char *mac_key,
                 const unsigned char *iv, const size_t ivlen,
-                unsigned char *shared_key, size_t shared_len);
+                unsigned char *shared_key);
 /*============== miscellaneous functions============================= */
 /* from gost_sign.c */
 /* Convert GOST R 34.11 hash sum to bignum according to standard */