From df692a6167be5486f9a29da003a00292fd895176 Mon Sep 17 00:00:00 2001
From: Werner Koch <wk@gnupg.org>
Date: Mon, 18 Sep 2017 22:49:05 +0200
Subject: [PATCH] dirmngr: Use system certs if --hkp-cacert is not used.

* dirmngr/certcache.c (any_cert_of_class): New var.
(put_cert): Set it.
(cert_cache_deinit): Clear it.
(cert_cache_any_in_class): New func.
* dirmngr/http-ntbtls.c (gnupg_http_tls_verify_cb): Add hack to
override empty list of HKP certs.
--

This patch carries the changes for GNUTLS from commit
7c1613d41566f7d8db116790087de323621205fe over to NTBTLS.  NTBTLS works
quite different and thus we need to do it this way.

Signed-off-by: Werner Koch <wk@gnupg.org>
---
 dirmngr/certcache.c   | 18 +++++++++++++++++-
 dirmngr/certcache.h   |  3 +++
 dirmngr/http-ntbtls.c |  6 ++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/dirmngr/certcache.c b/dirmngr/certcache.c
index b4e538131..56629fdda 100644
--- a/dirmngr/certcache.c
+++ b/dirmngr/certcache.c
@@ -94,6 +94,10 @@ static int initialization_done;
 /* Total number of non-permanent certificates.  */
 static unsigned int total_nonperm_certificates;
 
+/* For each cert class the corresponding bit is set if at least one
+ * certificate of that class is loaded permanetly.  */
+static unsigned int any_cert_of_class;
+
 
 #ifdef HAVE_W32_SYSTEM
 /* We load some functions dynamically.  Provide typedefs for tehse
@@ -343,7 +347,9 @@ put_cert (ksba_cert_t cert, int permanent, unsigned int trustclass,
   ci->permanent = !!permanent;
   ci->trustclasses = trustclass;
 
-  if (!permanent)
+  if (permanent)
+    any_cert_of_class |= trustclass;
+  else
     total_nonperm_certificates++;
 
   return 0;
@@ -758,6 +764,7 @@ cert_cache_deinit (int full)
     }
 
   total_nonperm_certificates = 0;
+  any_cert_of_class = 0;
   initialization_done = 0;
   release_cache_lock ();
 }
@@ -814,6 +821,15 @@ cert_cache_print_stats (void)
 }
 
 
+/* Return true if any cert of a class in MASK is permanently
+ * loaded.  */
+int
+cert_cache_any_in_class (unsigned int mask)
+{
+  return !!(any_cert_of_class & mask);
+}
+
+
 /* Put CERT into the certificate cache.  */
 gpg_error_t
 cache_cert (ksba_cert_t cert)
diff --git a/dirmngr/certcache.h b/dirmngr/certcache.h
index 92529bf11..8d645836d 100644
--- a/dirmngr/certcache.h
+++ b/dirmngr/certcache.h
@@ -39,6 +39,9 @@ void cert_cache_deinit (int full);
 /* Print some statistics to the log file.  */
 void cert_cache_print_stats (void);
 
+/* Return true if any cert of a class in MASK is permanently loaded.  */
+int cert_cache_any_in_class (unsigned int mask);
+
 /* Compute the fingerprint of the certificate CERT and put it into
    the 20 bytes large buffer DIGEST.  Return address of this buffer.  */
 unsigned char *cert_compute_fpr (ksba_cert_t cert, unsigned char *digest);
diff --git a/dirmngr/http-ntbtls.c b/dirmngr/http-ntbtls.c
index 250db556c..ea66a4d73 100644
--- a/dirmngr/http-ntbtls.c
+++ b/dirmngr/http-ntbtls.c
@@ -91,6 +91,12 @@ gnupg_http_tls_verify_cb (void *opaque,
         validate_flags |= VALIDATE_FLAG_TRUST_HKP;
       if ((http_flags & HTTP_FLAG_TRUST_SYS))
         validate_flags |= VALIDATE_FLAG_TRUST_SYSTEM;
+
+      /* If HKP trust is requested and there are no HKP certificates
+       * configured, also try thye standard system certificates.  */
+      if ((validate_flags & VALIDATE_FLAG_TRUST_HKP)
+          && !cert_cache_any_in_class (CERTTRUST_CLASS_HKP))
+        validate_flags |= VALIDATE_FLAG_TRUST_SYSTEM;
     }
 
   if ((http_flags & HTTP_FLAG_NO_CRL))