cofactor is optional in parameter encodings

Submitted by: Nils Larsch

diff --git a/crypto/ec/ec_asn1.c b/crypto/ec/ec_asn1.c
index 63d33a5f56ddda4ce57b7eab23c2cb2c045ba83b..c1c6ffee5ad589e0f05c7ab87facf22ccdbaf8ee 100644 (file)
--- a/crypto/ec/ec_asn1.c
+++ b/crypto/ec/ec_asn1.c
@@ -3,7 +3,7 @@
  * Written by Nils Larsch for the OpenSSL project.
  */
 /* ====================================================================
- * Copyright (c) 2000-2002 The OpenSSL Project.  All rights reserved.
+ * Copyright (c) 2000-2003 The OpenSSL Project.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -224,7 +224,7 @@ ASN1_SEQUENCE(ECPARAMETERS) = {
        ASN1_SIMPLE(ECPARAMETERS, curve, X9_62_CURVE),
        ASN1_SIMPLE(ECPARAMETERS, base, ASN1_OCTET_STRING),
        ASN1_SIMPLE(ECPARAMETERS, order, ASN1_INTEGER),
-       ASN1_SIMPLE(ECPARAMETERS, cofactor, ASN1_INTEGER)
+       ASN1_OPT(ECPARAMETERS, cofactor, ASN1_INTEGER)
 } ASN1_SEQUENCE_END(ECPARAMETERS)
 
 DECLARE_ASN1_FUNCTIONS_const(ECPARAMETERS)
@@ -715,17 +715,15 @@ static ECPARAMETERS *ec_asn1_group2parameters(const EC_GROUP *group,
                goto err;
                }
 
-       /* set the cofactor */
-       if (!EC_GROUP_get_cofactor(group, tmp, NULL))
+       /* set the cofactor (optional) */
+       if (EC_GROUP_get_cofactor(group, tmp, NULL))
                {
-               ECerr(EC_F_EC_ASN1_GROUP2PARAMETERS, ERR_R_EC_LIB);
-               goto err;
-               }
-       ret->cofactor = BN_to_ASN1_INTEGER(tmp, ret->cofactor);
-       if (ret->cofactor == NULL)
-               {
-               ECerr(EC_F_EC_ASN1_GROUP2PARAMETERS, ERR_R_ASN1_LIB);
-               goto err;
+               ret->cofactor = BN_to_ASN1_INTEGER(tmp, ret->cofactor);
+               if (ret->cofactor == NULL)
+                       {
+                       ECerr(EC_F_EC_ASN1_GROUP2PARAMETERS, ERR_R_ASN1_LIB);
+                       goto err;
+                       }
                }
 
        ok = 1;
@@ -978,9 +976,7 @@ static EC_GROUP *ec_asn1_parameters2group(const ECPARAMETERS *params)
                ret->seed_len = params->curve->seed->length;
                }
 
-       /* extract the order, cofactor and generator */
-       if (!params->order || !params->cofactor || !params->base ||
-           !params->base->data)
+       if (!params->order || !params->base || !params->base->data)
                {
                ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, EC_R_ASN1_ERROR);
                goto err;
@@ -988,14 +984,11 @@ static EC_GROUP *ec_asn1_parameters2group(const ECPARAMETERS *params)
 
        if ((point = EC_POINT_new(ret)) == NULL) goto err;
 
-       a = ASN1_INTEGER_to_BN(params->order, a);
-       b = ASN1_INTEGER_to_BN(params->cofactor, b);
-       if (!a || !b)
-               {
-               ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, ERR_R_ASN1_LIB);
-               goto err;
-               }
+       /* set the point conversion form */
+       EC_GROUP_set_point_conversion_form(ret, (point_conversion_form_t)
+                               (params->base->data[0] & ~0x01));
 
+       /* extract the ec point */
        if (!EC_POINT_oct2point(ret, point, params->base->data, 
                                params->base->length, NULL))
                {
@@ -1003,10 +996,29 @@ static EC_GROUP *ec_asn1_parameters2group(const ECPARAMETERS *params)
                goto err;
                }
 
-       /* set the point conversion form */
-       EC_GROUP_set_point_conversion_form(ret, (point_conversion_form_t)
-                               (params->base->data[0] & ~0x01));
-
+       /* extract the order */
+       if ((a = ASN1_INTEGER_to_BN(params->order, a)) == NULL)
+               {
+               ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, ERR_R_ASN1_LIB);
+               goto err;
+               }
+       
+       /* extract the cofactor (optional) */
+       if (params->cofactor == NULL)
+               {
+               if (b)
+                       {
+                       BN_free(b);
+                       b = NULL;
+                       }
+               }
+       else
+               if ((b = ASN1_INTEGER_to_BN(params->cofactor, b)) == NULL)
+                       {
+                       ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, ERR_R_ASN1_LIB);
+                       goto err;
+                       }
+       /* set the generator, order and cofactor (if present) */
        if (!EC_GROUP_set_generator(ret, point, a, b))
                {
                ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, ERR_R_EC_LIB);