Add a check_trust call to the legacy chain validation on chain add, remembering

the result in order to return the same errors as OpenSSL users expect to override
the generic "Untrusted cert" error.

This fixes the openssl-ruby timestamp test.

ok tb@

Author: beck

src/lib/libcrypto/x509/x509_verify.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: x509_verify.c,v 1.40 2021/08/18 15:10:46 beck Exp $ */
+/* $OpenBSD: x509_verify.c,v 1.41 2021/08/18 15:32:38 beck Exp $ */
 /*
  * Copyright (c) 2020-2021 Bob Beck <beck@openbsd.org>
  *
@@ -312,7 +312,7 @@ static int
 x509_verify_ctx_validate_legacy_chain(struct x509_verify_ctx *ctx,
     struct x509_verify_chain *chain, size_t depth)
 {
-	int ret = 0;
+	int ret = 0, trust;
 
 	if (ctx->xsc == NULL)
 		return 1;
@@ -330,6 +330,10 @@ x509_verify_ctx_validate_legacy_chain(struct x509_verify_ctx *ctx,
 	ctx->xsc->error = X509_V_OK;
 	ctx->xsc->error_depth = 0;
 
+	trust = x509_vfy_check_trust(ctx->xsc);
+	if (trust == X509_TRUST_REJECTED)
+		goto err;
+
 	if (!x509_verify_ctx_set_xsc_chain(ctx, chain, 0, 1))
 		goto err;
 
@@ -354,6 +358,10 @@ x509_verify_ctx_validate_legacy_chain(struct x509_verify_ctx *ctx,
 	if (!x509_vfy_check_policy(ctx->xsc))
 		goto err;
 
+	if ((!(ctx->xsc->param->flags & X509_V_FLAG_PARTIAL_CHAIN)) &&
+	    trust != X509_TRUST_TRUSTED)
+		goto err;
+
 	ret = 1;
 
  err: