Fixed size check in ecc_get_key, Fixes #630

Author: ulikos

src/pk/ecc/ecc_get_key.c

@@ -33,8 +33,11 @@ int ecc_get_key(unsigned char *out, unsigned long *outlen, int type, const ecc_k
    }
    else if (type == PK_PRIVATE) {
       if (key->type != PK_PRIVATE)                                                return CRYPT_PK_TYPE_MISMATCH;
+      if (size > *outlen) {
+         *outlen = size;
+         return CRYPT_BUFFER_OVERFLOW;
+      }
       *outlen = size;
-      if (size > *outlen)                                                         return CRYPT_BUFFER_OVERFLOW;
       if ((ksize = mp_unsigned_bin_size(key->k)) > size)                          return CRYPT_BUFFER_OVERFLOW;
       /* pad and store k */
       if ((err = mp_to_unsigned_bin(key->k, out + (size - ksize))) != CRYPT_OK)   return err;