New EC functions.

New functions EC_POINT_point2buf and EC_KEY_key2buf which encode
a point and allocate a buffer in one call.

New function EC_KEY_oct2key() which sets public key in an EC_KEY
structure from an encoded point.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

crypto/ec/ec_asn1.c

@@ -578,19 +578,11 @@ static ECPARAMETERS *ec_asn1_group2parameters(const EC_GROUP *group,
 
     form = EC_GROUP_get_point_conversion_form(group);
 
-    len = EC_POINT_point2oct(group, point, form, NULL, len, NULL);
+    len = EC_POINT_point2buf(group, point, form, &buffer, NULL);
     if (len == 0) {
         ECerr(EC_F_EC_ASN1_GROUP2PARAMETERS, ERR_R_EC_LIB);
         goto err;
     }
-    if ((buffer = OPENSSL_malloc(len)) == NULL) {
-        ECerr(EC_F_EC_ASN1_GROUP2PARAMETERS, ERR_R_MALLOC_FAILURE);
-        goto err;
-    }
-    if (!EC_POINT_point2oct(group, point, form, buffer, len, NULL)) {
-        ECerr(EC_F_EC_ASN1_GROUP2PARAMETERS, ERR_R_EC_LIB);
-        goto err;
-    }
     if (ret->base == NULL && (ret->base = ASN1_OCTET_STRING_new()) == NULL) {
         ECerr(EC_F_EC_ASN1_GROUP2PARAMETERS, ERR_R_MALLOC_FAILURE);
         goto err;

crypto/ec/ec_key.c

@@ -575,3 +575,23 @@ void EC_KEY_clear_flags(EC_KEY *key, int flags)
 {
     key->flags &= ~flags;
 }
+
+size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
+                        unsigned char **pbuf, BN_CTX *ctx)
+{
+    if (key == NULL || key->pub_key == NULL || key->group == NULL)
+        return 0;
+    return EC_POINT_point2buf(key->group, key->pub_key, form, pbuf, ctx);
+}
+
+int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len,
+                   BN_CTX *ctx)
+{
+    if (key == NULL || key->group == NULL)
+        return 0;
+    if (key->pub_key == NULL)
+        key->pub_key = EC_POINT_new(key->group);
+    if (key->pub_key == NULL)
+        return 0;
+    return EC_POINT_oct2point(key->group, key->pub_key, buf, len, ctx);
+}

crypto/ec/ec_oct.c

@@ -190,3 +190,24 @@ int EC_POINT_oct2point(const EC_GROUP *group, EC_POINT *point,
     }
     return group->meth->oct2point(group, point, buf, len, ctx);
 }
+
+size_t EC_POINT_point2buf(const EC_GROUP *group, const EC_POINT *point,
+                          point_conversion_form_t form,
+                          unsigned char **pbuf, BN_CTX *ctx)
+{
+    size_t len;
+    unsigned char *buf;
+    len = EC_POINT_point2oct(group, point, form, NULL, 0, NULL);
+    if (len == 0)
+        return 0;
+    buf = OPENSSL_malloc(len);
+    if (buf == NULL)
+        return 0;
+    len = EC_POINT_point2oct(group, point, form, buf, len, ctx);
+    if (len == 0) {
+        OPENSSL_free(buf);
+        return 0;
+    }
+    *pbuf = buf;
+    return len;
+}

crypto/ec/ec_print.c

@@ -64,17 +64,10 @@ BIGNUM *EC_POINT_point2bn(const EC_GROUP *group,
     size_t buf_len = 0;
     unsigned char *buf;
 
-    buf_len = EC_POINT_point2oct(group, point, form, NULL, 0, ctx);
-    if (buf_len == 0)
-        return NULL;
-
-    if ((buf = OPENSSL_malloc(buf_len)) == NULL)
-        return NULL;
+    buf_len = EC_POINT_point2buf(group, point, form, &buf, ctx);
 
-    if (!EC_POINT_point2oct(group, point, form, buf, buf_len, ctx)) {
-        OPENSSL_free(buf);
+    if (buf_len == 0)
         return NULL;
-    }
 
     ret = BN_bin2bn(buf, buf_len, ret);
 
@@ -129,19 +122,12 @@ char *EC_POINT_point2hex(const EC_GROUP *group,
 {
     char *ret, *p;
     size_t buf_len = 0, i;
-    unsigned char *buf, *pbuf;
+    unsigned char *buf = NULL, *pbuf;
 
-    buf_len = EC_POINT_point2oct(group, point, form, NULL, 0, ctx);
-    if (buf_len == 0)
-        return NULL;
-
-    if ((buf = OPENSSL_malloc(buf_len)) == NULL)
-        return NULL;
+    buf_len = EC_POINT_point2buf(group, point, form, &buf, ctx);
 
-    if (!EC_POINT_point2oct(group, point, form, buf, buf_len, ctx)) {
-        OPENSSL_free(buf);
+    if (buf_len == 0)
         return NULL;
-    }
 
     ret = OPENSSL_malloc(buf_len * 2 + 2);
     if (ret == NULL) {

include/openssl/ec.h

@@ -589,6 +589,20 @@ size_t EC_POINT_point2oct(const EC_GROUP *group, const EC_POINT *p,
 int EC_POINT_oct2point(const EC_GROUP *group, EC_POINT *p,
                        const unsigned char *buf, size_t len, BN_CTX *ctx);
 
+/** Encodes an EC_POINT object to an allocated octet string
+ *  \param  group  underlying EC_GROUP object
+ *  \param  point  EC_POINT object
+ *  \param  form   point conversion form
+ *  \param  pbuf   returns pointer to allocated buffer
+ *  \param  len    length of the memory buffer
+ *  \param  ctx    BN_CTX object (optional)
+ *  \return the length of the encoded octet string or 0 if an error occurred
+ */
+
+size_t EC_POINT_point2buf(const EC_GROUP *group, const EC_POINT *point,
+                          point_conversion_form_t form,
+                          unsigned char **pbuf, BN_CTX *ctx);
+
 /* other interfaces to point2oct/oct2point: */
 BIGNUM *EC_POINT_point2bn(const EC_GROUP *, const EC_POINT *,
                           point_conversion_form_t form, BIGNUM *, BN_CTX *);
@@ -887,6 +901,29 @@ int EC_KEY_check_key(const EC_KEY *key);
 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
                                              BIGNUM *y);
 
+/** Encodes an EC_KEY public key to an allocated octet string
+ *  \param  key    key to encode
+ *  \param  form   point conversion form
+ *  \param  pbuf   returns pointer to allocated buffer
+ *  \param  len    length of the memory buffer
+ *  \param  ctx    BN_CTX object (optional)
+ *  \return the length of the encoded octet string or 0 if an error occurred
+ */
+
+size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
+                      unsigned char **pbuf, BN_CTX *ctx);
+
+/** Decodes a EC_KEY public key from a octet string
+ *  \param  key    key to decode
+ *  \param  buf    memory buffer with the encoded ec point
+ *  \param  len    length of the encoded ec point
+ *  \param  ctx    BN_CTX object (optional)
+ *  \return 1 on success and 0 if an error occurred
+ */
+
+int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len,
+                   BN_CTX *ctx);
+
 /********************************************************************/
 /*        de- and encoding functions for SEC1 ECPrivateKey          */
 /********************************************************************/