dirmngr: Check for WKD support at session end

* dirmngr/domaininfo.c (insert_or_update): Copy the name.
* dirmngr/misc.c (copy_stream): Allow arg OUT to be NULL.
* dirmngr/server.c (set_error): Protect CTX.
(dirmngr_status): Protect against missing ASSUAN_CTX.
(dirmngr_status_help): Ditto.
(dirmngr_status_printf): Ditto.
(cmd_wkd_get): Factor code out to ...
(proc_wkd_get): new func.  Support silent operation with no CTX.
(task_check_wkd_support): New.
--

This finalizes the feature to efficiently cache WKD checks.  If a
standard WKD query returns no data, we queue a test to be run after
the end of the session (so that we do not delay the calling client).
This check tests whether the server responsible for the queried
address has WKD at all enabled.  The test is done by checking whether
the "policy" file exists.  We do not check the "submission-address"
file because that is not necessary for the web key operation.  The
policy file is now required.

Signed-off-by: Werner Koch <[email protected]>
(cherry picked from commit d4e2302d8f4a1ff52d56da4f8e3a5d1c6303822d)

1 files changed, 56 insertions, 23 deletions

diff --git a/dirmngr/server.c b/dirmngr/server.c
index 1fbd007a0..3d0768b2a 100644
--- a/dirmngr/server.c
+++ b/dirmngr/server.c
@@ -80,7 +80,8 @@
 
 #define PARM_ERROR(t) assuan_set_error (ctx, \
                                         gpg_error (GPG_ERR_ASS_PARAMETER), (t))
-#define set_error(e,t) assuan_set_error (ctx, gpg_error (e), (t))
+#define set_error(e,t) (ctx ? assuan_set_error (ctx, gpg_error (e), (t)) \
+                        /**/: gpg_error (e))
 
 
 
@@ -828,15 +829,11 @@ cmd_dns_cert (assuan_context_t ctx, char *line)
 
 
 
-static const char hlp_wkd_get[] =
-  "WKD_GET [--submission-address|--policy-flags] <user_id>\n"
-  "\n"
-  "Return the key or other info for <user_id>\n"
-  "from the Web Key Directory.";
+/* Core of cmd_wkd_get and task_check_wkd_support.  If CTX is NULL
+ * this function will not write anything to the assuan output.  */
 static gpg_error_t
-cmd_wkd_get (assuan_context_t ctx, char *line)
+proc_wkd_get (ctrl_t ctrl, assuan_context_t ctx, char *line)
 {
-  ctrl_t ctrl = assuan_get_pointer (ctx);
   gpg_error_t err = 0;
   char *mbox = NULL;
   char *domainbuf = NULL;
@@ -895,7 +892,8 @@ cmd_wkd_get (assuan_context_t ctx, char *line)
       domainlen = strlen (domain);
       for (i = 0; i < srvscount; i++)
         {
-          log_debug ("srv: trying '%s:%hu'\n", srvs[i].target, srvs[i].port);
+          if (DBG_DNS)
+            log_debug ("srv: trying '%s:%hu'\n", srvs[i].target, srvs[i].port);
           targetlen = strlen (srvs[i].target);
           if ((targetlen > domainlen + 1
                && srvs[i].target[targetlen - domainlen - 1] == '.'
@@ -972,19 +970,24 @@ cmd_wkd_get (assuan_context_t ctx, char *line)
   {
     estream_t outfp;
 
-    outfp = es_fopencookie (ctx, "w", data_line_cookie_functions);
-    if (!outfp)
+    outfp = ctx? es_fopencookie (ctx, "w", data_line_cookie_functions) : NULL;
+    if (!outfp && ctx)
       err = set_error (GPG_ERR_ASS_GENERAL,
                        "error setting up a data stream");
     else
       {
-        if (no_log)
-          ctrl->server_local->inhibit_data_logging = 1;
-        ctrl->server_local->inhibit_data_logging_now = 0;
-        ctrl->server_local->inhibit_data_logging_count = 0;
+        if (ctrl->server_local)
+          {
+            if (no_log)
+              ctrl->server_local->inhibit_data_logging = 1;
+            ctrl->server_local->inhibit_data_logging_now = 0;
+            ctrl->server_local->inhibit_data_logging_count = 0;
+          }
         err = ks_action_fetch (ctrl, uri, outfp);
         es_fclose (outfp);
-        ctrl->server_local->inhibit_data_logging = 0;
+        if (ctrl->server_local)
+          ctrl->server_local->inhibit_data_logging = 0;
+
         /* Register the result under the domain name of MBOX. */
         switch (gpg_err_code (err))
           {
@@ -998,8 +1001,9 @@ cmd_wkd_get (assuan_context_t ctx, char *line)
             break;
 
           case GPG_ERR_NO_DATA:
-            if (is_wkd_query) /* Mark that and schedule a check.  */
+            if (is_wkd_query && ctrl->server_local)
               {
+                /* Mark that and schedule a check.  */
                 domaininfo_set_wkd_not_found (domain_orig);
                 workqueue_add_task (task_check_wkd_support, domain_orig,
                                     ctrl->server_local->session_id, 1);
@@ -1020,6 +1024,23 @@ cmd_wkd_get (assuan_context_t ctx, char *line)
   xfree (encodedhash);
   xfree (mbox);
   xfree (domainbuf);
+  return err;
+}
+
+
+static const char hlp_wkd_get[] =
+  "WKD_GET [--submission-address|--policy-flags] <user_id>\n"
+  "\n"
+  "Return the key or other info for <user_id>\n"
+  "from the Web Key Directory.";
+static gpg_error_t
+cmd_wkd_get (assuan_context_t ctx, char *line)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+  gpg_error_t err;
+
+  err = proc_wkd_get (ctrl, ctx, line);
+
   return leave_cmd (ctx, err);
 }
 
@@ -1029,10 +1050,19 @@ cmd_wkd_get (assuan_context_t ctx, char *line)
 static const char *
 task_check_wkd_support (ctrl_t ctrl, const char *domain)
 {
+  char *string;
+
   if (!ctrl || !domain)
     return "check_wkd_support";
 
-  log_debug ("FIXME: Implement %s\n", __func__);
+  string = strconcat ("--policy-flags foo@", domain, NULL);
+  if (!string)
+    log_error ("%s: %s\n", __func__, gpg_strerror (gpg_error_from_syserror ()));
+  else
+    {
+      proc_wkd_get (ctrl, NULL, string);
+      xfree (string);
+    }
 
   return NULL;
 }
@@ -2800,12 +2830,12 @@ dirmngr_status (ctrl_t ctrl, const char *keyword, ...)
   gpg_error_t err = 0;
   va_list arg_ptr;
   const char *text;
+  assuan_context_t ctx;
 
   va_start (arg_ptr, keyword);
 
-  if (ctrl->server_local)
+  if (ctrl->server_local && (ctx = ctrl->server_local->assuan_ctx))
     {
-      assuan_context_t ctx = ctrl->server_local->assuan_ctx;
       char buf[950], *p;
       size_t n;
 
@@ -2835,10 +2865,10 @@ gpg_error_t
 dirmngr_status_help (ctrl_t ctrl, const char *text)
 {
   gpg_error_t err = 0;
+  assuan_context_t ctx;
 
-  if (ctrl->server_local)
+  if (ctrl->server_local && (ctx = ctrl->server_local->assuan_ctx))
     {
-      assuan_context_t ctx = ctrl->server_local->assuan_ctx;
       char buf[950], *p;
       size_t n;
 
@@ -2888,7 +2918,10 @@ dirmngr_status_printf (ctrl_t ctrl, const char *keyword,
 {
   gpg_error_t err;
   va_list arg_ptr;
-  assuan_context_t ctx = ctrl->server_local->assuan_ctx;
+  assuan_context_t ctx;
+
+  if (!ctrl->server_local || !(ctx = ctrl->server_local->assuan_ctx))
+    return 0;
 
   va_start (arg_ptr, format);
   err = vprint_assuan_status (ctx, keyword, format, arg_ptr);