Initial code to support distinct certificate and CRL signing keys where the

CRL issuer is not part of the main path.

Not complete yet and not compiled in because the CRL issuer certificate is
not validated.

crypto/x509/x509_vfy.c

@@ -795,6 +795,9 @@ static int crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl, X509 **pissuer)
 	{
 	X509 *crl_issuer;
 	int cidx = ctx->error_depth;
+#if 0
+	int i;
+#endif
 	if (!crl->akid)
 		return 1;
 	if (cidx != sk_X509_num(ctx->chain) - 1)
@@ -819,7 +822,31 @@ static int crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl, X509 **pissuer)
 				break;
 			}
 		}
-		
+
+
+	/* Otherwise the CRL issuer is not on the path. Look for it in the
+	 * set of untrusted certificates.
+	 */
+
+#if 0
+	/* FIXME: not enabled yet because the CRL issuer certifcate is not
+	 * validated.
+	 */
+
+	for (i = 0; i < sk_X509_num(ctx->untrusted); i++)
+		{
+		crl_issuer = sk_X509_value(ctx->untrusted, i);
+		if (X509_NAME_cmp(X509_get_subject_name(crl_issuer),
+					X509_CRL_get_issuer(crl)))
+			continue;
+		if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK)
+			{
+			*pissuer = crl_issuer;
+			return 1;
+			}
+		}
+#endif
+
 	return 0;
 	}