dirmngr: Change to new ADNS Tor mode init scheme.

* dirmngr/dns-stuff.c (tor_credentials): New.
(enable_dns_tormode): Add arg new_circuit and update tor_credentials.
(my_adns_init): Rework to set Tor mode using a config file options and
always use credentials.
* dirmngr/server.c (cmd_dns_cert): Improve error message.
* dirmngr/t-dns-stuff.c (main): Add option --new-circuit.
--

Note that the option --new-circuit in t-dns-stuff is not really useful
because a new circuit is also used for the first call to the function.

Todo: We need to find a policy when to requrest a new curcuit and we
      also need to add credentials to the assuan_sock_connect calls.

Signed-off-by: Werner Koch <wk@gnupg.org>

dirmngr/dns-stuff.c

@@ -85,17 +85,32 @@
 /* If set Tor mode shall be used.  */
 static int tor_mode;
 
+/* A string to hold the credentials presented to Tor.  */
+#ifdef USE_ADNS
+static char tor_credentials[50];
+#endif
+
 /* Sets the module in Tor mode.  Returns 0 is this is possible or an
    error code.  */
 gpg_error_t
-enable_dns_tormode (void)
+enable_dns_tormode (int new_circuit)
 {
 #if defined(USE_DNS_CERT) && defined(USE_ADNS)
 # if HAVE_ADNS_IF_TORMODE
+   if (!*tor_credentials || new_circuit)
+     {
+       static unsigned int counter;
+
+       gpgrt_snprintf (tor_credentials, sizeof tor_credentials,
+                       "dirmngr-%lu:p%u",
+                       (unsigned long)getpid (), counter);
+       counter++;
+     }
    tor_mode = 1;
    return 0;
 # endif
 #endif
+
   return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
 }
 
@@ -145,14 +160,35 @@ map_eai_to_gpg_error (int ec)
 static gpg_error_t
 my_adns_init (adns_state *r_state)
 {
-  gpg_error_t err;
+  gpg_error_t err = 0;
+  int ret;
 
-  if (tor_mode? adns_init_strcfg (r_state,
-                                  adns_if_noerrprint|adns_if_tormode,
-                                  NULL, "nameserver 8.8.8.8")
-      /*    */: adns_init (r_state, adns_if_noerrprint, NULL))
+  if (tor_mode)
+    {
+      char *cfgstr;
+
+      cfgstr = xtryasprintf ("nameserver %s\n"
+                             "options adns_tormode adns_sockscred:%s",
+                             "8.8.8.8", tor_credentials);
+      if (!cfgstr)
+        err = gpg_error_from_syserror ();
+      else
+        {
+          ret = adns_init_strcfg (r_state, adns_if_noerrprint, NULL, cfgstr);
+          if (ret)
+            err = gpg_error_from_errno (ret);
+          xfree (cfgstr);
+        }
+    }
+  else
+    {
+      ret = adns_init (r_state, adns_if_noerrprint, NULL);
+      if (ret)
+        err = gpg_error_from_errno (ret);
+    }
+
+  if (err)
     {
-      err = gpg_error_from_syserror ();
       log_error ("error initializing adns: %s\n", gpg_strerror (err));
       return err;
     }
@@ -176,6 +212,9 @@ resolve_name_adns (const char *name, unsigned short port,
   adns_answer *answer = NULL;
   int count;
 
+  (void)port;
+  (void)want_family;
+
   *r_dai = NULL;
   if (r_canonname)
     *r_canonname = NULL;

dirmngr/dns-stuff.h

@@ -94,7 +94,7 @@ struct srventry
 
 /* Calling this function switches the DNS code into Tor mode if
    possibe.  Return 0 on success.  */
-gpg_error_t enable_dns_tormode (void);
+gpg_error_t enable_dns_tormode (int new_circuit);
 
 void free_dns_addrinfo (dns_addrinfo_t ai);
 

dirmngr/server.c

@@ -714,10 +714,10 @@ cmd_dns_cert (assuan_context_t ctx, char *line)
         }
     }
 
-  if (opt.use_tor && enable_dns_tormode ())
+  if (opt.use_tor && (err = enable_dns_tormode (0)))
     {
       /* Tor mode is requested but the DNS code can't enable it.  */
-      err = gpg_error (GPG_ERR_FORBIDDEN);
+      assuan_set_error (ctx, err, "error enabling Tor mode");
       goto leave;
     }
 

dirmngr/t-dns-stuff.c

@@ -41,6 +41,7 @@ main (int argc, char **argv)
   gpg_error_t err;
   int any_options = 0;
   int opt_tor = 0;
+  int opt_new_circuit = 0;
   int opt_cert = 0;
   int opt_srv = 0;
   int opt_bracket = 0;
@@ -66,6 +67,7 @@ main (int argc, char **argv)
                  "  --verbose         print timings etc.\n"
                  "  --debug           flyswatter\n"
                  "  --use-tor         use Tor\n"
+                 "  --new-circuit     use a new Tor circuit\n"
                  "  --bracket         enclose v6 addresses in brackets\n"
                  "  --cert            lookup a CERT RR\n"
                  "  --srv             lookup a SRV RR\n"
@@ -89,6 +91,11 @@ main (int argc, char **argv)
           opt_tor = 1;
           argc--; argv++;
         }
+      else if (!strcmp (*argv, "--new-circuit"))
+        {
+          opt_new_circuit = 1;
+          argc--; argv++;
+        }
       else if (!strcmp (*argv, "--bracket"))
         {
           opt_bracket = 1;
@@ -131,7 +138,7 @@ main (int argc, char **argv)
 
   if (opt_tor)
     {
-      err = enable_dns_tormode ();
+      err = enable_dns_tormode (opt_new_circuit);
       if (err)
         {
           fprintf (stderr, "error switching into Tor mode: %s\n",