Add EC_GROUP_order_bits, EC_GROUP_get0_order and EC_GROUP_get0_cofactor

New functions to return internal pointer for order and cofactor. This
avoids the need to allocate a new BIGNUM which to copy the value to.
Simplify code to use new functions.

Reviewed-by: Rich Salz <rsalz@openssl.org>

1 files changed, 29 insertions, 5 deletions

diff --git a/crypto/ec/ec_lib.c b/crypto/ec/ec_lib.c
index f81489d20d..ac3903cbce 100644
--- a/crypto/ec/ec_lib.c
+++ b/crypto/ec/ec_lib.c
@@ -349,21 +349,43 @@ BN_MONT_CTX *EC_GROUP_get_mont_data(const EC_GROUP *group)
 
 int EC_GROUP_get_order(const EC_GROUP *group, BIGNUM *order, BN_CTX *ctx)
 {
+    if (group->order == NULL)
+        return 0;
     if (!BN_copy(order, group->order))
         return 0;
 
     return !BN_is_zero(order);
 }
 
+const BIGNUM *EC_GROUP_get0_order(const EC_GROUP *group)
+{
+    return group->order;
+}
+
+int EC_GROUP_order_bits(const EC_GROUP *group)
+{
+    if (group->order)
+        return BN_num_bits(group->order);
+    return 0;
+}
+
 int EC_GROUP_get_cofactor(const EC_GROUP *group, BIGNUM *cofactor,
                           BN_CTX *ctx)
 {
+
+    if (group->cofactor == NULL)
+        return 0;
     if (!BN_copy(cofactor, group->cofactor))
         return 0;
 
     return !BN_is_zero(group->cofactor);
 }
 
+const BIGNUM *EC_GROUP_get0_cofactor(const EC_GROUP *group)
+{
+    return group->cofactor;
+}
+
 void EC_GROUP_set_curve_name(EC_GROUP *group, int nid)
 {
     group->curve_name = nid;
@@ -536,16 +558,18 @@ int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ctx)
         r = 1;
 
     if (!r) {
+        const BIGNUM *ao, *bo, *ac, *bc;
         /* compare the order and cofactor */
-        if (!EC_GROUP_get_order(a, a1, ctx) ||
-            !EC_GROUP_get_order(b, b1, ctx) ||
-            !EC_GROUP_get_cofactor(a, a2, ctx) ||
-            !EC_GROUP_get_cofactor(b, b2, ctx)) {
+        ao = EC_GROUP_get0_order(a);
+        bo = EC_GROUP_get0_order(b);
+        ac = EC_GROUP_get0_cofactor(a);
+        bc = EC_GROUP_get0_cofactor(b);
+        if (ao == NULL || bo == NULL) {
             BN_CTX_end(ctx);
             BN_CTX_free(ctx_new);
             return -1;
         }
-        if (BN_cmp(a1, b1) || BN_cmp(a2, b2))
+        if (BN_cmp(ao, bo) || BN_cmp(ac, bc))
             r = 1;
     }