Simplify field and private key encoding

Reach into the group (p and order are always available) and use
BN_num_bytes() rather than using clumsy and badly named API.
It's shorter and more readable.

ok jsing

1 files changed, 3 insertions, 13 deletions

diff --git a/src/lib/libcrypto/ec/ec_asn1.c b/src/lib/libcrypto/ec/ec_asn1.c
index faca6059e4..ef318f8d43 100644
--- a/src/lib/libcrypto/ec/ec_asn1.c
+++ b/src/lib/libcrypto/ec/ec_asn1.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_asn1.c,v 1.110 2025/01/25 10:27:58 tb Exp $ */
+/* $OpenBSD: ec_asn1.c,v 1.111 2025/03/13 10:31:12 tb Exp $ */
 /*
  * Written by Nils Larsch for the OpenSSL project.
  */
@@ -701,26 +701,16 @@ static int
 ec_asn1_encode_field_element(const EC_GROUP *group, const BIGNUM *bn,
     ASN1_OCTET_STRING *os)
 {
-        int len;
-
         /* Zero-pad field element to byte length of p per SEC 1, 2.3.5. */
-        len = (EC_GROUP_get_degree(group) + 7) / 8;
-        return ec_asn1_encode_bn(group, bn, len, os);
+        return ec_asn1_encode_bn(group, bn, BN_num_bytes(group->p), os);
 }
 
 static int
 ec_asn1_encode_private_key(const EC_GROUP *group, const BIGNUM *bn,
     ASN1_OCTET_STRING *os)
 {
-        const BIGNUM *order;
-
-        if ((order = EC_GROUP_get0_order(group)) == NULL) {
-                ECerror(EC_R_INVALID_GROUP_ORDER);
-                return 0;
-        }
-
         /* Zero-pad private key to byte length of order per SEC 1, C.4. */
-        return ec_asn1_encode_bn(group, bn, BN_num_bytes(order), os);
+        return ec_asn1_encode_bn(group, bn, BN_num_bytes(group->order), os);
 }
 
 static int