Add support getting raw private/public keys

Only applies to algorithms that support it. Both raw private and public
keys can be obtained for X25519, Ed25519, X448, Ed448. Raw private keys
only can be obtained for HMAC, Poly1305 and SipHash

Fixes #6259
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NTim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6394)

crypto/ec/ecx_meth.c

@@ -354,6 +354,47 @@ static int ecx_set_pub_key(EVP_PKEY *pkey, const unsigned char *pub, size_t len)
                       KEY_OP_PUBLIC);
 }
 
+static int ecx_get_priv_key(const EVP_PKEY *pkey, unsigned char *priv,
+                            size_t *len)
+{
+    const ECX_KEY *key = pkey->pkey.ecx;
+
+    if (priv == NULL) {
+        *len = KEYLENID(pkey->ameth->pkey_id);
+        return 1;
+    }
+
+    if (key == NULL
+            || key->privkey == NULL
+            || *len < (size_t)KEYLENID(pkey->ameth->pkey_id))
+        return 0;
+
+    *len = KEYLENID(pkey->ameth->pkey_id);
+    memcpy(priv, key->privkey, *len);
+
+    return 1;
+}
+
+static int ecx_get_pub_key(const EVP_PKEY *pkey, unsigned char *pub,
+                           size_t *len)
+{
+    const ECX_KEY *key = pkey->pkey.ecx;
+
+    if (pub == NULL) {
+        *len = KEYLENID(pkey->ameth->pkey_id);
+        return 1;
+    }
+
+    if (key == NULL
+            || *len < (size_t)KEYLENID(pkey->ameth->pkey_id))
+        return 0;
+
+    *len = KEYLENID(pkey->ameth->pkey_id);
+    memcpy(pub, key->pubkey, *len);
+
+    return 1;
+}
+
 const EVP_PKEY_ASN1_METHOD ecx25519_asn1_meth = {
     EVP_PKEY_X25519,
     EVP_PKEY_X25519,
@@ -393,6 +434,8 @@ const EVP_PKEY_ASN1_METHOD ecx25519_asn1_meth = {
 
     ecx_set_priv_key,
     ecx_set_pub_key,
+    ecx_get_priv_key,
+    ecx_get_pub_key,
 };
 
 const EVP_PKEY_ASN1_METHOD ecx448_asn1_meth = {
@@ -434,6 +477,8 @@ const EVP_PKEY_ASN1_METHOD ecx448_asn1_meth = {
 
     ecx_set_priv_key,
     ecx_set_pub_key,
+    ecx_get_priv_key,
+    ecx_get_pub_key,
 };
 
 static int ecd_size25519(const EVP_PKEY *pkey)
@@ -547,6 +592,8 @@ const EVP_PKEY_ASN1_METHOD ed25519_asn1_meth = {
 
     ecx_set_priv_key,
     ecx_set_pub_key,
+    ecx_get_priv_key,
+    ecx_get_pub_key,
 };
 
 const EVP_PKEY_ASN1_METHOD ed448_asn1_meth = {
@@ -587,6 +634,8 @@ const EVP_PKEY_ASN1_METHOD ed448_asn1_meth = {
 
     ecx_set_priv_key,
     ecx_set_pub_key,
+    ecx_get_priv_key,
+    ecx_get_pub_key,
 };
 
 static int pkey_ecx_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)

crypto/err/openssl.txt

@@ -757,6 +757,8 @@ EVP_F_EVP_PKEY_GET0_HMAC:183:EVP_PKEY_get0_hmac
 EVP_F_EVP_PKEY_GET0_POLY1305:184:EVP_PKEY_get0_poly1305
 EVP_F_EVP_PKEY_GET0_RSA:121:EVP_PKEY_get0_RSA
 EVP_F_EVP_PKEY_GET0_SIPHASH:172:EVP_PKEY_get0_siphash
+EVP_F_EVP_PKEY_GET_RAW_PRIVATE_KEY:202:EVP_PKEY_get_raw_private_key
+EVP_F_EVP_PKEY_GET_RAW_PUBLIC_KEY:203:EVP_PKEY_get_raw_public_key
 EVP_F_EVP_PKEY_KEYGEN:146:EVP_PKEY_keygen
 EVP_F_EVP_PKEY_KEYGEN_INIT:147:EVP_PKEY_keygen_init
 EVP_F_EVP_PKEY_METH_ADD0:194:EVP_PKEY_meth_add0
@@ -2199,6 +2201,7 @@ EVP_R_EXPECTING_A_EC_KEY:142:expecting a ec key
 EVP_R_EXPECTING_A_POLY1305_KEY:164:expecting a poly1305 key
 EVP_R_EXPECTING_A_SIPHASH_KEY:175:expecting a siphash key
 EVP_R_FIPS_MODE_NOT_SUPPORTED:167:fips mode not supported
+EVP_R_GET_RAW_KEY_FAILED:182:get raw key failed
 EVP_R_ILLEGAL_SCRYPT_PARAMETERS:171:illegal scrypt parameters
 EVP_R_INITIALIZATION_ERROR:134:initialization error
 EVP_R_INPUT_NOT_INITIALIZED:111:input not initialized

crypto/evp/evp_err.c

@@ -93,6 +93,10 @@ static const ERR_STRING_DATA EVP_str_functs[] = {
     {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY_GET0_RSA, 0), "EVP_PKEY_get0_RSA"},
     {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY_GET0_SIPHASH, 0),
      "EVP_PKEY_get0_siphash"},
+    {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY_GET_RAW_PRIVATE_KEY, 0),
+     "EVP_PKEY_get_raw_private_key"},
+    {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY_GET_RAW_PUBLIC_KEY, 0),
+     "EVP_PKEY_get_raw_public_key"},
     {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY_KEYGEN, 0), "EVP_PKEY_keygen"},
     {ERR_PACK(ERR_LIB_EVP, EVP_F_EVP_PKEY_KEYGEN_INIT, 0),
      "EVP_PKEY_keygen_init"},
@@ -185,6 +189,7 @@ static const ERR_STRING_DATA EVP_str_reasons[] = {
     "expecting a siphash key"},
     {ERR_PACK(ERR_LIB_EVP, 0, EVP_R_FIPS_MODE_NOT_SUPPORTED),
     "fips mode not supported"},
+    {ERR_PACK(ERR_LIB_EVP, 0, EVP_R_GET_RAW_KEY_FAILED), "get raw key failed"},
     {ERR_PACK(ERR_LIB_EVP, 0, EVP_R_ILLEGAL_SCRYPT_PARAMETERS),
     "illegal scrypt parameters"},
     {ERR_PACK(ERR_LIB_EVP, 0, EVP_R_INITIALIZATION_ERROR),

crypto/evp/p_lib.c

@@ -280,6 +280,40 @@ EVP_PKEY *EVP_PKEY_new_raw_public_key(int type, ENGINE *e,
     return NULL;
 }
 
+int EVP_PKEY_get_raw_private_key(const EVP_PKEY *pkey, unsigned char *priv,
+                                 size_t *len)
+{
+     if (pkey->ameth->get_priv_key == NULL) {
+        EVPerr(EVP_F_EVP_PKEY_GET_RAW_PRIVATE_KEY,
+               EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
+        return 0;
+    }
+
+    if (!pkey->ameth->get_priv_key(pkey, priv, len)) {
+        EVPerr(EVP_F_EVP_PKEY_GET_RAW_PRIVATE_KEY, EVP_R_GET_RAW_KEY_FAILED);
+        return 0;
+    }
+
+    return 1;
+}
+
+int EVP_PKEY_get_raw_public_key(const EVP_PKEY *pkey, unsigned char *pub,
+                                size_t *len)
+{
+     if (pkey->ameth->get_pub_key == NULL) {
+        EVPerr(EVP_F_EVP_PKEY_GET_RAW_PUBLIC_KEY,
+               EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
+        return 0;
+    }
+
+    if (!pkey->ameth->get_pub_key(pkey, pub, len)) {
+        EVPerr(EVP_F_EVP_PKEY_GET_RAW_PUBLIC_KEY, EVP_R_GET_RAW_KEY_FAILED);
+        return 0;
+    }
+
+    return 1;
+}
+
 EVP_PKEY *EVP_PKEY_new_CMAC_key(ENGINE *e, const unsigned char *priv,
                                 size_t len, const EVP_CIPHER *cipher)
 {

crypto/hmac/hm_ameth.c

@@ -72,6 +72,25 @@ static int hmac_set_priv_key(EVP_PKEY *pkey, const unsigned char *priv,
     return 1;
 }
 
+static int hmac_get_priv_key(const EVP_PKEY *pkey, unsigned char *priv,
+                             size_t *len)
+{
+    ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;
+
+    if (priv == NULL) {
+        *len = ASN1_STRING_length(os);
+        return 1;
+    }
+
+    if (os == NULL || *len < (size_t)ASN1_STRING_length(os))
+        return 0;
+
+    *len = ASN1_STRING_length(os);
+    memcpy(priv, ASN1_STRING_get0_data(os), *len);
+
+    return 1;
+}
+
 const EVP_PKEY_ASN1_METHOD hmac_asn1_meth = {
     EVP_PKEY_HMAC,
     EVP_PKEY_HMAC,
@@ -103,4 +122,6 @@ const EVP_PKEY_ASN1_METHOD hmac_asn1_meth = {
 
     hmac_set_priv_key,
     NULL,
+    hmac_get_priv_key,
+    NULL,
 };

crypto/include/internal/asn1_int.h

@@ -61,6 +61,8 @@ struct evp_pkey_asn1_method_st {
     /* Get/set raw private/public key data */
     int (*set_priv_key) (EVP_PKEY *pk, const unsigned char *priv, size_t len);
     int (*set_pub_key) (EVP_PKEY *pk, const unsigned char *pub, size_t len);
+    int (*get_priv_key) (const EVP_PKEY *pk, unsigned char *priv, size_t *len);
+    int (*get_pub_key) (const EVP_PKEY *pk, unsigned char *pub, size_t *len);
 } /* EVP_PKEY_ASN1_METHOD */ ;
 
 DEFINE_STACK_OF_CONST(EVP_PKEY_ASN1_METHOD)

crypto/poly1305/poly1305_ameth.c

@@ -67,6 +67,25 @@ static int poly1305_set_priv_key(EVP_PKEY *pkey, const unsigned char *priv,
     return 1;
 }
 
+static int poly1305_get_priv_key(const EVP_PKEY *pkey, unsigned char *priv,
+                                 size_t *len)
+{
+    ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;
+
+    if (priv == NULL) {
+        *len = POLY1305_KEY_SIZE;
+        return 1;
+    }
+
+    if (os == NULL || *len < POLY1305_KEY_SIZE)
+        return 0;
+
+    memcpy(priv, ASN1_STRING_get0_data(os), ASN1_STRING_length(os));
+    *len = POLY1305_KEY_SIZE;
+
+    return 1;
+}
+
 const EVP_PKEY_ASN1_METHOD poly1305_asn1_meth = {
     EVP_PKEY_POLY1305,
     EVP_PKEY_POLY1305,
@@ -98,4 +117,6 @@ const EVP_PKEY_ASN1_METHOD poly1305_asn1_meth = {
 
     poly1305_set_priv_key,
     NULL,
+    poly1305_get_priv_key,
+    NULL,
 };

crypto/siphash/siphash_ameth.c

@@ -68,6 +68,25 @@ static int siphash_set_priv_key(EVP_PKEY *pkey, const unsigned char *priv,
     return 1;
 }
 
+static int siphash_get_priv_key(const EVP_PKEY *pkey, unsigned char *priv,
+                                size_t *len)
+{
+    ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;
+
+    if (priv == NULL) {
+        *len = SIPHASH_KEY_SIZE;
+        return 1;
+    }
+
+    if (os == NULL || *len < SIPHASH_KEY_SIZE)
+        return 0;
+
+    memcpy(priv, ASN1_STRING_get0_data(os), ASN1_STRING_length(os));
+    *len = SIPHASH_KEY_SIZE;
+
+    return 1;
+}
+
 const EVP_PKEY_ASN1_METHOD siphash_asn1_meth = {
     EVP_PKEY_SIPHASH,
     EVP_PKEY_SIPHASH,
@@ -99,4 +118,6 @@ const EVP_PKEY_ASN1_METHOD siphash_asn1_meth = {
 
     siphash_set_priv_key,
     NULL,
+    siphash_get_priv_key,
+    NULL,
 };

include/openssl/evp.h

@@ -1352,6 +1352,11 @@ EVP_PKEY *EVP_PKEY_new_raw_private_key(int type, ENGINE *e,
 EVP_PKEY *EVP_PKEY_new_raw_public_key(int type, ENGINE *e,
                                       const unsigned char *pub,
                                       size_t len);
+int EVP_PKEY_get_raw_private_key(const EVP_PKEY *pkey, unsigned char *priv,
+                                 size_t *len);
+int EVP_PKEY_get_raw_public_key(const EVP_PKEY *pkey, unsigned char *pub,
+                                size_t *len);
+
 EVP_PKEY *EVP_PKEY_new_CMAC_key(ENGINE *e, const unsigned char *priv,
                                 size_t len, const EVP_CIPHER *cipher);
 

include/openssl/evperr.h

@@ -79,6 +79,8 @@ int ERR_load_EVP_strings(void);
 # define EVP_F_EVP_PKEY_GET0_POLY1305                     184
 # define EVP_F_EVP_PKEY_GET0_RSA                          121
 # define EVP_F_EVP_PKEY_GET0_SIPHASH                      172
+# define EVP_F_EVP_PKEY_GET_RAW_PRIVATE_KEY               202
+# define EVP_F_EVP_PKEY_GET_RAW_PUBLIC_KEY                203
 # define EVP_F_EVP_PKEY_KEYGEN                            146
 # define EVP_F_EVP_PKEY_KEYGEN_INIT                       147
 # define EVP_F_EVP_PKEY_METH_ADD0                         194
@@ -139,6 +141,7 @@ int ERR_load_EVP_strings(void);
 # define EVP_R_EXPECTING_A_POLY1305_KEY                   164
 # define EVP_R_EXPECTING_A_SIPHASH_KEY                    175
 # define EVP_R_FIPS_MODE_NOT_SUPPORTED                    167
+# define EVP_R_GET_RAW_KEY_FAILED                         182
 # define EVP_R_ILLEGAL_SCRYPT_PARAMETERS                  171
 # define EVP_R_INITIALIZATION_ERROR                       134
 # define EVP_R_INPUT_NOT_INITIALIZED                      111

util/libcrypto.num

@@ -4563,3 +4563,5 @@ X509_OBJECT_set1_X509                   4514	1_1_0i	EXIST::FUNCTION:
 X509_LOOKUP_meth_get_get_by_issuer_serial 4515	1_1_0i	EXIST::FUNCTION:
 X509_LOOKUP_meth_set_init               4516	1_1_0i	EXIST::FUNCTION:
 X509_OBJECT_set1_X509_CRL               4517	1_1_0i	EXIST::FUNCTION:
+EVP_PKEY_get_raw_public_key             4518	1_1_1	EXIST::FUNCTION:
+EVP_PKEY_get_raw_private_key            4519	1_1_1	EXIST::FUNCTION: