Adding upstream version 2.2.27.upstream/2.2.27upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1595 insertions, 0 deletions

diff --git a/tools/gpg-wks-client.c b/tools/gpg-wks-client.c
new file mode 100644
index 0000000..4ebf50f
--- /dev/null
+++ b/tools/gpg-wks-client.c
@@ -0,0 +1,1595 @@
+/* gpg-wks-client.c - A client for the Web Key Service protocols.
+ * Copyright (C) 2016 Werner Koch
+ * Copyright (C) 2016 Bundesamt für Sicherheit in der Informationstechnik
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#define INCLUDED_BY_MAIN_MODULE 1
+#include "../common/util.h"
+#include "../common/status.h"
+#include "../common/i18n.h"
+#include "../common/sysutils.h"
+#include "../common/init.h"
+#include "../common/asshelp.h"
+#include "../common/userids.h"
+#include "../common/ccparray.h"
+#include "../common/exectool.h"
+#include "../common/mbox-util.h"
+#include "../common/name-value.h"
+#include "call-dirmngr.h"
+#include "mime-maker.h"
+#include "send-mail.h"
+#include "gpg-wks.h"
+
+
+/* Constants to identify the commands and options. */
+enum cmd_and_opt_values
+  {
+    aNull = 0,
+
+    oQuiet      = 'q',
+    oVerbose	= 'v',
+    oOutput     = 'o',
+    oDirectory  = 'C',
+
+    oDebug      = 500,
+
+    aSupported,
+    aCheck,
+    aCreate,
+    aReceive,
+    aRead,
+    aInstallKey,
+    aRemoveKey,
+    aPrintWKDHash,
+    aPrintWKDURL,
+
+    oGpgProgram,
+    oSend,
+    oFakeSubmissionAddr,
+    oStatusFD,
+    oWithColons,
+
+    oDummy
+  };
+
+
+/* The list of commands and options. */
+static ARGPARSE_OPTS opts[] = {
+  ARGPARSE_group (300, ("@Commands:\n ")),
+
+  ARGPARSE_c (aSupported, "supported",
+              ("check whether provider supports WKS")),
+  ARGPARSE_c (aCheck, "check",
+              ("check whether a key is available")),
+  ARGPARSE_c (aCreate,   "create",
+              ("create a publication request")),
+  ARGPARSE_c (aReceive,   "receive",
+              ("receive a MIME confirmation request")),
+  ARGPARSE_c (aRead,      "read",
+              ("receive a plain text confirmation request")),
+  ARGPARSE_c (aInstallKey, "install-key",
+              "install a key into a directory"),
+  ARGPARSE_c (aRemoveKey, "remove-key",
+              "remove a key from a directory"),
+  ARGPARSE_c (aPrintWKDHash, "print-wkd-hash",
+              "Print the WKD identifier for the given user ids"),
+  ARGPARSE_c (aPrintWKDURL, "print-wkd-url",
+              "Print the WKD URL for the given user id"),
+
+  ARGPARSE_group (301, ("@\nOptions:\n ")),
+
+  ARGPARSE_s_n (oVerbose, "verbose", ("verbose")),
+  ARGPARSE_s_n (oQuiet,	"quiet",  ("be somewhat more quiet")),
+  ARGPARSE_s_s (oDebug, "debug", "@"),
+  ARGPARSE_s_s (oGpgProgram, "gpg", "@"),
+  ARGPARSE_s_n (oSend, "send", "send the mail using sendmail"),
+  ARGPARSE_s_s (oOutput, "output", "|FILE|write the mail to FILE"),
+  ARGPARSE_s_i (oStatusFD, "status-fd", N_("|FD|write status info to this FD")),
+  ARGPARSE_s_n (oWithColons, "with-colons", "@"),
+  ARGPARSE_s_s (oDirectory, "directory", "@"),
+
+  ARGPARSE_s_s (oFakeSubmissionAddr, "fake-submission-addr", "@"),
+
+  ARGPARSE_end ()
+};
+
+
+/* The list of supported debug flags.  */
+static struct debug_flags_s debug_flags [] =
+  {
+    { DBG_MIME_VALUE   , "mime"    },
+    { DBG_PARSER_VALUE , "parser"  },
+    { DBG_CRYPTO_VALUE , "crypto"  },
+    { DBG_MEMORY_VALUE , "memory"  },
+    { DBG_MEMSTAT_VALUE, "memstat" },
+    { DBG_IPC_VALUE    , "ipc"     },
+    { DBG_EXTPROG_VALUE, "extprog" },
+    { 0, NULL }
+  };
+
+
+
+/* Value of the option --fake-submission-addr.  */
+const char *fake_submission_addr;
+
+
+static void wrong_args (const char *text) GPGRT_ATTR_NORETURN;
+static gpg_error_t proc_userid_from_stdin (gpg_error_t (*func)(const char *),
+                                           const char *text);
+static gpg_error_t command_supported (char *userid);
+static gpg_error_t command_check (char *userid);
+static gpg_error_t command_send (const char *fingerprint, const char *userid);
+static gpg_error_t encrypt_response (estream_t *r_output, estream_t input,
+                                     const char *addrspec,
+                                     const char *fingerprint);
+static gpg_error_t read_confirmation_request (estream_t msg);
+static gpg_error_t command_receive_cb (void *opaque,
+                                       const char *mediatype, estream_t fp,
+                                       unsigned int flags);
+
+
+
+/* Print usage information and provide strings for help. */
+static const char *
+my_strusage( int level )
+{
+  const char *p;
+
+  switch (level)
+    {
+    case  9: p = "LGPL-2.1-or-later"; break;
+    case 11: p = "gpg-wks-client"; break;
+    case 12: p = "@GNUPG@"; break;
+    case 13: p = VERSION; break;
+    case 14: p = GNUPG_DEF_COPYRIGHT_LINE; break;
+    case 17: p = PRINTABLE_OS_NAME; break;
+    case 19: p = ("Please report bugs to <@EMAIL@>.\n"); break;
+
+    case 1:
+    case 40:
+      p = ("Usage: gpg-wks-client [command] [options] [args] (-h for help)");
+      break;
+    case 41:
+      p = ("Syntax: gpg-wks-client [command] [options] [args]\n"
+           "Client for the Web Key Service\n");
+      break;
+
+    default: p = NULL; break;
+    }
+  return p;
+}
+
+
+static void
+wrong_args (const char *text)
+{
+  es_fprintf (es_stderr, _("usage: %s [options] %s\n"), strusage (11), text);
+  exit (2);
+}
+
+
+
+/* Command line parsing.  */
+static enum cmd_and_opt_values
+parse_arguments (ARGPARSE_ARGS *pargs, ARGPARSE_OPTS *popts)
+{
+  enum cmd_and_opt_values cmd = 0;
+  int no_more_options = 0;
+
+  while (!no_more_options && gnupg_argparse (NULL, pargs, popts))
+    {
+      switch (pargs->r_opt)
+        {
+	case oQuiet:     opt.quiet = 1; break;
+        case oVerbose:   opt.verbose++; break;
+        case oDebug:
+          if (parse_debug_flag (pargs->r.ret_str, &opt.debug, debug_flags))
+            {
+              pargs->r_opt = ARGPARSE_INVALID_ARG;
+              pargs->err = ARGPARSE_PRINT_ERROR;
+            }
+          break;
+
+        case oGpgProgram:
+          opt.gpg_program = pargs->r.ret_str;
+          break;
+        case oDirectory:
+          opt.directory = pargs->r.ret_str;
+          break;
+        case oSend:
+          opt.use_sendmail = 1;
+          break;
+        case oOutput:
+          opt.output = pargs->r.ret_str;
+          break;
+        case oFakeSubmissionAddr:
+          fake_submission_addr = pargs->r.ret_str;
+          break;
+        case oStatusFD:
+          wks_set_status_fd (translate_sys2libc_fd_int (pargs->r.ret_int, 1));
+          break;
+        case oWithColons:
+          opt.with_colons = 1;
+          break;
+
+	case aSupported:
+	case aCreate:
+	case aReceive:
+	case aRead:
+        case aCheck:
+        case aInstallKey:
+        case aRemoveKey:
+        case aPrintWKDHash:
+        case aPrintWKDURL:
+          cmd = pargs->r_opt;
+          break;
+
+        default: pargs->err = ARGPARSE_PRINT_ERROR; break;
+	}
+    }
+
+  return cmd;
+}
+
+
+
+/* gpg-wks-client main. */
+int
+main (int argc, char **argv)
+{
+  gpg_error_t err, delayed_err;
+  ARGPARSE_ARGS pargs;
+  enum cmd_and_opt_values cmd;
+
+  gnupg_reopen_std ("gpg-wks-client");
+  set_strusage (my_strusage);
+  log_set_prefix ("gpg-wks-client", GPGRT_LOG_WITH_PREFIX);
+
+  /* Make sure that our subsystems are ready.  */
+  i18n_init();
+  init_common_subsystems (&argc, &argv);
+
+  assuan_set_gpg_err_source (GPG_ERR_SOURCE_DEFAULT);
+  setup_libassuan_logging (&opt.debug, NULL);
+
+  /* Parse the command line. */
+  pargs.argc  = &argc;
+  pargs.argv  = &argv;
+  pargs.flags = ARGPARSE_FLAG_KEEP;
+  cmd = parse_arguments (&pargs, opts);
+  gnupg_argparse (NULL, &pargs, NULL);
+
+  if (log_get_errorcount (0))
+    exit (2);
+
+  /* Print a warning if an argument looks like an option.  */
+  if (!opt.quiet && !(pargs.flags & ARGPARSE_FLAG_STOP_SEEN))
+    {
+      int i;
+
+      for (i=0; i < argc; i++)
+        if (argv[i][0] == '-' && argv[i][1] == '-')
+          log_info (("NOTE: '%s' is not considered an option\n"), argv[i]);
+    }
+
+  /* Set defaults for non given options.  */
+  if (!opt.gpg_program)
+    opt.gpg_program = gnupg_module_name (GNUPG_MODULE_NAME_GPG);
+
+  if (!opt.directory)
+    opt.directory = "openpgpkey";
+
+  /* Tell call-dirmngr what options we want.  */
+  set_dirmngr_options (opt.verbose, (opt.debug & DBG_IPC_VALUE), 1);
+
+
+  /* Check that the top directory exists.  */
+  if (cmd == aInstallKey || cmd == aRemoveKey)
+    {
+      struct stat sb;
+
+      if (gnupg_stat (opt.directory, &sb))
+        {
+          err = gpg_error_from_syserror ();
+          log_error ("error accessing directory '%s': %s\n",
+                     opt.directory, gpg_strerror (err));
+          goto leave;
+        }
+      if (!S_ISDIR(sb.st_mode))
+        {
+          log_error ("error accessing directory '%s': %s\n",
+                     opt.directory, "not a directory");
+          err = gpg_error (GPG_ERR_ENOENT);
+          goto leave;
+        }
+    }
+
+  /* Run the selected command.  */
+  switch (cmd)
+    {
+    case aSupported:
+      if (opt.with_colons)
+        {
+          for (; argc; argc--, argv++)
+            command_supported (*argv);
+          err = 0;
+        }
+      else
+        {
+          if (argc != 1)
+            wrong_args ("--supported DOMAIN");
+          err = command_supported (argv[0]);
+          if (err && gpg_err_code (err) != GPG_ERR_FALSE)
+            log_error ("checking support failed: %s\n", gpg_strerror (err));
+        }
+      break;
+
+    case aCreate:
+      if (argc != 2)
+        wrong_args ("--create FINGERPRINT USER-ID");
+      err = command_send (argv[0], argv[1]);
+      if (err)
+        log_error ("creating request failed: %s\n", gpg_strerror (err));
+      break;
+
+    case aReceive:
+      if (argc)
+        wrong_args ("--receive < MIME-DATA");
+      err = wks_receive (es_stdin, command_receive_cb, NULL);
+      if (err)
+        log_error ("processing mail failed: %s\n", gpg_strerror (err));
+      break;
+
+    case aRead:
+      if (argc)
+        wrong_args ("--read < WKS-DATA");
+      err = read_confirmation_request (es_stdin);
+      if (err)
+        log_error ("processing mail failed: %s\n", gpg_strerror (err));
+      break;
+
+    case aCheck:
+      if (argc != 1)
+        wrong_args ("--check USER-ID");
+      err = command_check (argv[0]);
+      break;
+
+    case aInstallKey:
+      if (!argc)
+        err = wks_cmd_install_key (NULL, NULL);
+      else if (argc == 2)
+        err = wks_cmd_install_key (*argv, argv[1]);
+      else
+        wrong_args ("--install-key [FILE|FINGERPRINT USER-ID]");
+      break;
+
+    case aRemoveKey:
+      if (argc != 1)
+        wrong_args ("--remove-key USER-ID");
+      err = wks_cmd_remove_key (*argv);
+      break;
+
+    case aPrintWKDHash:
+    case aPrintWKDURL:
+      if (!argc)
+        {
+          if (cmd == aPrintWKDHash)
+            err = proc_userid_from_stdin (wks_cmd_print_wkd_hash,
+                                          "printing WKD hash");
+          else
+            err = proc_userid_from_stdin (wks_cmd_print_wkd_url,
+                                          "printing WKD URL");
+        }
+      else
+        {
+          for (err = delayed_err = 0; !err && argc; argc--, argv++)
+            {
+              if (cmd == aPrintWKDHash)
+                err = wks_cmd_print_wkd_hash (*argv);
+              else
+                err = wks_cmd_print_wkd_url (*argv);
+              if (gpg_err_code (err) == GPG_ERR_INV_USER_ID)
+                {
+                  /* Diagnostic already printed.  */
+                  delayed_err = err;
+                  err = 0;
+                }
+              else if (err)
+                log_error ("printing hash failed: %s\n", gpg_strerror (err));
+            }
+          if (!err)
+            err = delayed_err;
+        }
+      break;
+
+    default:
+      usage (1);
+      err = 0;
+      break;
+    }
+
+ leave:
+  if (err)
+    wks_write_status (STATUS_FAILURE, "- %u", err);
+  else if (log_get_errorcount (0))
+    wks_write_status (STATUS_FAILURE, "- %u", GPG_ERR_GENERAL);
+  else
+    wks_write_status (STATUS_SUCCESS, NULL);
+  return (err || log_get_errorcount (0))? 1:0;
+}
+
+
+/* Read user ids from stdin and call FUNC for each user id.  TEXT is
+ * used for error messages.  */
+static gpg_error_t
+proc_userid_from_stdin (gpg_error_t (*func)(const char *), const char *text)
+{
+  gpg_error_t err = 0;
+  gpg_error_t delayed_err = 0;
+  char line[2048];
+  size_t n = 0;
+
+  /* If we are on a terminal disable buffering to get direct response.  */
+  if (gnupg_isatty (es_fileno (es_stdin))
+      && gnupg_isatty (es_fileno (es_stdout)))
+    {
+      es_setvbuf (es_stdin, NULL, _IONBF, 0);
+      es_setvbuf (es_stdout, NULL, _IOLBF, 0);
+    }
+
+  while (es_fgets (line, sizeof line - 1, es_stdin))
+    {
+      n = strlen (line);
+      if (!n || line[n-1] != '\n')
+        {
+          err = gpg_error (*line? GPG_ERR_LINE_TOO_LONG
+                           : GPG_ERR_INCOMPLETE_LINE);
+          log_error ("error reading stdin: %s\n", gpg_strerror (err));
+          break;
+        }
+      trim_spaces (line);
+      err = func (line);
+      if (gpg_err_code (err) == GPG_ERR_INV_USER_ID)
+        {
+          delayed_err = err;
+          err = 0;
+        }
+      else if (err)
+        log_error ("%s failed: %s\n", text, gpg_strerror (err));
+    }
+  if (es_ferror (es_stdin))
+    {
+      err = gpg_error_from_syserror ();
+      log_error ("error reading stdin: %s\n", gpg_strerror (err));
+      goto leave;
+    }
+
+ leave:
+  if (!err)
+    err = delayed_err;
+  return err;
+}
+
+
+
+
+/* Add the user id UID to the key identified by FINGERPRINT.  */
+static gpg_error_t
+add_user_id (const char *fingerprint, const char *uid)
+{
+  gpg_error_t err;
+  ccparray_t ccp;
+  const char **argv = NULL;
+
+  ccparray_init (&ccp, 0);
+
+  ccparray_put (&ccp, "--no-options");
+  if (!opt.verbose)
+    ccparray_put (&ccp, "--quiet");
+  else if (opt.verbose > 1)
+    ccparray_put (&ccp, "--verbose");
+  ccparray_put (&ccp, "--batch");
+  ccparray_put (&ccp, "--always-trust");
+  ccparray_put (&ccp, "--quick-add-uid");
+  ccparray_put (&ccp, fingerprint);
+  ccparray_put (&ccp, uid);
+
+  ccparray_put (&ccp, NULL);
+  argv = ccparray_get (&ccp, NULL);
+  if (!argv)
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+  err = gnupg_exec_tool_stream (opt.gpg_program, argv, NULL,
+                                NULL, NULL,
+                                NULL, NULL);
+  if (err)
+    {
+      log_error ("adding user id failed: %s\n", gpg_strerror (err));
+      goto leave;
+    }
+
+ leave:
+  xfree (argv);
+  return err;
+}
+
+
+
+struct decrypt_stream_parm_s
+{
+  char *fpr;
+  char *mainfpr;
+  int  otrust;
+};
+
+static void
+decrypt_stream_status_cb (void *opaque, const char *keyword, char *args)
+{
+  struct decrypt_stream_parm_s *decinfo = opaque;
+
+  if (DBG_CRYPTO)
+    log_debug ("gpg status: %s %s\n", keyword, args);
+  if (!strcmp (keyword, "DECRYPTION_KEY") && !decinfo->fpr)
+    {
+      char *fields[3];
+
+      if (split_fields (args, fields, DIM (fields)) >= 3)
+        {
+          decinfo->fpr = xstrdup (fields[0]);
+          decinfo->mainfpr = xstrdup (fields[1]);
+          decinfo->otrust = *fields[2];
+        }
+    }
+}
+
+/* Decrypt the INPUT stream to a new stream which is stored at success
+ * at R_OUTPUT.  */
+static gpg_error_t
+decrypt_stream (estream_t *r_output, struct decrypt_stream_parm_s *decinfo,
+                estream_t input)
+{
+  gpg_error_t err;
+  ccparray_t ccp;
+  const char **argv;
+  estream_t output;
+
+  *r_output = NULL;
+  memset (decinfo, 0, sizeof *decinfo);
+
+  output = es_fopenmem (0, "w+b");
+  if (!output)
+    {
+      err = gpg_error_from_syserror ();
+      log_error ("error allocating memory buffer: %s\n", gpg_strerror (err));
+      return err;
+    }
+
+  ccparray_init (&ccp, 0);
+
+  ccparray_put (&ccp, "--no-options");
+  /* We limit the output to 64 KiB to avoid DoS using compression
+   * tricks.  A regular client will anyway only send a minimal key;
+   * that is one w/o key signatures and attribute packets.  */
+  ccparray_put (&ccp, "--max-output=0x10000");
+  if (!opt.verbose)
+    ccparray_put (&ccp, "--quiet");
+  else if (opt.verbose > 1)
+    ccparray_put (&ccp, "--verbose");
+  ccparray_put (&ccp, "--batch");
+  ccparray_put (&ccp, "--status-fd=2");
+  ccparray_put (&ccp, "--decrypt");
+  ccparray_put (&ccp, "--");
+
+  ccparray_put (&ccp, NULL);
+  argv = ccparray_get (&ccp, NULL);
+  if (!argv)
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+  err = gnupg_exec_tool_stream (opt.gpg_program, argv, input,
+                                NULL, output,
+                                decrypt_stream_status_cb, decinfo);
+  if (!err && (!decinfo->fpr || !decinfo->mainfpr || !decinfo->otrust))
+    err = gpg_error (GPG_ERR_INV_ENGINE);
+  if (err)
+    {
+      log_error ("decryption failed: %s\n", gpg_strerror (err));
+      goto leave;
+    }
+  else if (opt.verbose)
+    log_info ("decryption succeeded\n");
+
+  es_rewind (output);
+  *r_output = output;
+  output = NULL;
+
+ leave:
+  if (err)
+    {
+      xfree (decinfo->fpr);
+      xfree (decinfo->mainfpr);
+      memset (decinfo, 0, sizeof *decinfo);
+    }
+  es_fclose (output);
+  xfree (argv);
+  return err;
+}
+
+
+/* Return the submission address for the address or just the domain in
+ * ADDRSPEC.  The submission address is stored as a malloced string at
+ * R_SUBMISSION_ADDRESS.  At R_POLICY the policy flags of the domain
+ * are stored.  The caller needs to free them with wks_free_policy.
+ * The function returns an error code on failure to find a submission
+ * address or policy file.  Note: The function may store NULL at
+ * R_SUBMISSION_ADDRESS but return success to indicate that the web
+ * key directory is supported but not the web key service.  As per WKD
+ * specs a policy file is always required and will thus be return on
+ * success.  */
+static gpg_error_t
+get_policy_and_sa (const char *addrspec, int silent,
+                   policy_flags_t *r_policy, char **r_submission_address)
+{
+  gpg_error_t err;
+  estream_t mbuf = NULL;
+  const char *domain;
+  const char *s;
+  policy_flags_t policy = NULL;
+  char *submission_to = NULL;
+
+  *r_submission_address = NULL;
+  *r_policy = NULL;
+
+  domain = strchr (addrspec, '@');
+  if (domain)
+    domain++;
+
+  if (opt.with_colons)
+    {
+      s = domain? domain : addrspec;
+      es_write_sanitized (es_stdout, s, strlen (s), ":", NULL);
+      es_putc (':', es_stdout);
+    }
+
+  /* We first try to get the submission address from the policy file
+   * (this is the new method).  If both are available we check that
+   * they match and print a warning if not.  In the latter case we
+   * keep on using the one from the submission-address file.    */
+  err = wkd_get_policy_flags (addrspec, &mbuf);
+  if (err && gpg_err_code (err) != GPG_ERR_NO_DATA
+      && gpg_err_code (err) != GPG_ERR_NO_NAME)
+    {
+      if (!opt.with_colons)
+        log_error ("error reading policy flags for '%s': %s\n",
+                   domain, gpg_strerror (err));
+      goto leave;
+    }
+  if (!mbuf)
+    {
+      if (!opt.with_colons)
+        log_error ("provider for '%s' does NOT support the Web Key Directory\n",
+                   addrspec);
+      err = gpg_error (GPG_ERR_FALSE);
+      goto leave;
+    }
+
+  policy = xtrycalloc (1, sizeof *policy);
+  if (!policy)
+    err = gpg_error_from_syserror ();
+  else
+    err = wks_parse_policy (policy, mbuf, 1);
+  es_fclose (mbuf);
+  mbuf = NULL;
+  if (err)
+    goto leave;
+
+  err = wkd_get_submission_address (addrspec, &submission_to);
+  if (err && !policy->submission_address)
+    {
+      if (!silent && !opt.with_colons)
+        log_error (_("error looking up submission address for domain '%s'"
+                     ": %s\n"), domain, gpg_strerror (err));
+      if (!silent && gpg_err_code (err) == GPG_ERR_NO_DATA && !opt.with_colons)
+        log_error (_("this domain probably doesn't support WKS.\n"));
+      goto leave;
+    }
+
+  if (submission_to && policy->submission_address
+      && ascii_strcasecmp (submission_to, policy->submission_address))
+    log_info ("Warning: different submission addresses (sa=%s, po=%s)\n",
+              submission_to, policy->submission_address);
+
+  if (!submission_to && policy->submission_address)
+    {
+      submission_to = xtrystrdup (policy->submission_address);
+      if (!submission_to)
+        {
+          err = gpg_error_from_syserror ();
+          goto leave;
+        }
+    }
+
+ leave:
+  *r_submission_address = submission_to;
+  submission_to = NULL;
+  *r_policy = policy;
+  policy = NULL;
+
+  if (opt.with_colons)
+    {
+      if (*r_policy && !*r_submission_address)
+        es_fprintf (es_stdout, "1:0::");
+      else if (*r_policy && *r_submission_address)
+        es_fprintf (es_stdout, "1:1::");
+      else if (err && !(gpg_err_code (err) == GPG_ERR_FALSE
+                        || gpg_err_code (err) == GPG_ERR_NO_DATA
+                        || gpg_err_code (err) == GPG_ERR_UNKNOWN_HOST))
+        es_fprintf (es_stdout, "0:0:%d:", err);
+      else
+        es_fprintf (es_stdout, "0:0::");
+      if (*r_policy)
+        {
+          es_fprintf (es_stdout, "%u:%u:%u:",
+                      (*r_policy)->protocol_version,
+                      (*r_policy)->auth_submit,
+                      (*r_policy)->mailbox_only);
+        }
+      es_putc ('\n', es_stdout);
+    }
+
+  xfree (submission_to);
+  wks_free_policy (policy);
+  xfree (policy);
+  es_fclose (mbuf);
+  return err;
+}
+
+
+
+/* Check whether the  provider supports the WKS protocol.  */
+static gpg_error_t
+command_supported (char *userid)
+{
+  gpg_error_t err;
+  char *addrspec = NULL;
+  char *submission_to = NULL;
+  policy_flags_t policy = NULL;
+
+  if (!strchr (userid, '@'))
+    {
+      char *tmp = xstrconcat ("foo@", userid, NULL);
+      addrspec = mailbox_from_userid (tmp);
+      xfree (tmp);
+    }
+  else
+    addrspec = mailbox_from_userid (userid);
+  if (!addrspec)
+    {
+      log_error (_("\"%s\" is not a proper mail address\n"), userid);
+      err = gpg_error (GPG_ERR_INV_USER_ID);
+      goto leave;
+    }
+
+  /* Get the submission address.  */
+  err = get_policy_and_sa (addrspec, 1, &policy, &submission_to);
+  if (err || !submission_to)
+    {
+      if (!submission_to
+          || gpg_err_code (err) == GPG_ERR_FALSE
+          || gpg_err_code (err) == GPG_ERR_NO_DATA
+          || gpg_err_code (err) == GPG_ERR_UNKNOWN_HOST
+          )
+        {
+          /* FALSE is returned if we already figured out that even the
+           * Web Key Directory is not supported and thus printed an
+           * error message.  */
+          if (opt.verbose && gpg_err_code (err) != GPG_ERR_FALSE
+              && !opt.with_colons)
+            {
+              if (gpg_err_code (err) == GPG_ERR_NO_DATA)
+                log_info ("provider for '%s' does NOT support WKS\n",
+                          addrspec);
+              else
+                log_info ("provider for '%s' does NOT support WKS (%s)\n",
+                          addrspec, gpg_strerror (err));
+            }
+          err = gpg_error (GPG_ERR_FALSE);
+          if (!opt.with_colons)
+            log_inc_errorcount ();
+        }
+      goto leave;
+    }
+
+  if (opt.verbose && !opt.with_colons)
+    log_info ("provider for '%s' supports WKS\n", addrspec);
+
+ leave:
+  wks_free_policy (policy);
+  xfree (policy);
+  xfree (submission_to);
+  xfree (addrspec);
+  return err;
+}
+
+
+
+/* Check whether the key for USERID is available in the WKD.  */
+static gpg_error_t
+command_check (char *userid)
+{
+  gpg_error_t err;
+  char *addrspec = NULL;
+  estream_t key = NULL;
+  char *fpr = NULL;
+  uidinfo_list_t mboxes = NULL;
+  uidinfo_list_t sl;
+  int found = 0;
+
+  addrspec = mailbox_from_userid (userid);
+  if (!addrspec)
+    {
+      log_error (_("\"%s\" is not a proper mail address\n"), userid);
+      err = gpg_error (GPG_ERR_INV_USER_ID);
+      goto leave;
+    }
+
+  /* Get the submission address.  */
+  err = wkd_get_key (addrspec, &key);
+  switch (gpg_err_code (err))
+    {
+    case 0:
+      if (opt.verbose)
+        log_info ("public key for '%s' found via WKD\n", addrspec);
+      /* Fixme: Check that the key contains the user id.  */
+      break;
+
+    case GPG_ERR_NO_DATA: /* No such key.  */
+      if (opt.verbose)
+        log_info ("public key for '%s' NOT found via WKD\n", addrspec);
+      err = gpg_error (GPG_ERR_NO_PUBKEY);
+      log_inc_errorcount ();
+      break;
+
+    case GPG_ERR_UNKNOWN_HOST:
+      if (opt.verbose)
+        log_info ("error looking up '%s' via WKD: %s\n",
+                  addrspec, gpg_strerror (err));
+      err = gpg_error (GPG_ERR_NOT_SUPPORTED);
+      break;
+
+    default:
+      log_error ("error looking up '%s' via WKD: %s\n",
+                 addrspec, gpg_strerror (err));
+      break;
+    }
+
+  if (err)
+    goto leave;
+
+  /* Look closer at the key.  */
+  err = wks_list_key (key, &fpr, &mboxes);
+  if (err)
+    {
+      log_error ("error parsing key: %s\n", gpg_strerror (err));
+      err = gpg_error (GPG_ERR_NO_PUBKEY);
+      goto leave;
+    }
+
+  if (opt.verbose)
+    log_info ("fingerprint: %s\n", fpr);
+
+  for (sl = mboxes; sl; sl = sl->next)
+    {
+      if (sl->mbox && !strcmp (sl->mbox, addrspec))
+        found = 1;
+      if (opt.verbose)
+        {
+          log_info ("    user-id: %s\n", sl->uid);
+          log_info ("    created: %s\n", asctimestamp (sl->created));
+          if (sl->mbox)
+            log_info ("  addr-spec: %s\n", sl->mbox);
+        }
+    }
+  if (!found)
+    {
+      log_error ("public key for '%s' has no user id with the mail address\n",
+                 addrspec);
+      err = gpg_error (GPG_ERR_CERT_REVOKED);
+    }
+
+ leave:
+  xfree (fpr);
+  free_uidinfo_list (mboxes);
+  es_fclose (key);
+  xfree (addrspec);
+  return err;
+}
+
+
+
+/* Locate the key by fingerprint and userid and send a publication
+ * request.  */
+static gpg_error_t
+command_send (const char *fingerprint, const char *userid)
+{
+  gpg_error_t err;
+  KEYDB_SEARCH_DESC desc;
+  char *addrspec = NULL;
+  estream_t key = NULL;
+  estream_t keyenc = NULL;
+  char *submission_to = NULL;
+  mime_maker_t mime = NULL;
+  policy_flags_t policy = NULL;
+  int no_encrypt = 0;
+  int posteo_hack = 0;
+  const char *domain;
+  uidinfo_list_t uidlist = NULL;
+  uidinfo_list_t uid, thisuid;
+  time_t thistime;
+
+  if (classify_user_id (fingerprint, &desc, 1)
+      || !(desc.mode == KEYDB_SEARCH_MODE_FPR
+           || desc.mode == KEYDB_SEARCH_MODE_FPR20))
+    {
+      log_error (_("\"%s\" is not a fingerprint\n"), fingerprint);
+      err = gpg_error (GPG_ERR_INV_NAME);
+      goto leave;
+    }
+
+  addrspec = mailbox_from_userid (userid);
+  if (!addrspec)
+    {
+      log_error (_("\"%s\" is not a proper mail address\n"), userid);
+      err = gpg_error (GPG_ERR_INV_USER_ID);
+      goto leave;
+    }
+  err = wks_get_key (&key, fingerprint, addrspec, 0);
+  if (err)
+    goto leave;
+
+  domain = strchr (addrspec, '@');
+  log_assert (domain);
+  domain++;
+
+  /* Get the submission address.  */
+  if (fake_submission_addr)
+    {
+      policy = xcalloc (1, sizeof *policy);
+      submission_to = xstrdup (fake_submission_addr);
+      err = 0;
+    }
+  else
+    {
+      err = get_policy_and_sa (addrspec, 0, &policy, &submission_to);
+      if (err)
+        goto leave;
+      if (!submission_to)
+        {
+          log_error (_("this domain probably doesn't support WKS.\n"));
+          err = gpg_error (GPG_ERR_NO_DATA);
+          goto leave;
+        }
+    }
+
+  log_info ("submitting request to '%s'\n", submission_to);
+
+  if (policy->auth_submit)
+    log_info ("no confirmation required for '%s'\n", addrspec);
+
+  /* In case the key has several uids with the same addr-spec we will
+   * use the newest one.  */
+  err = wks_list_key (key, NULL, &uidlist);
+  if (err)
+    {
+      log_error ("error parsing key: %s\n",gpg_strerror (err));
+      err = gpg_error (GPG_ERR_NO_PUBKEY);
+      goto leave;
+    }
+  thistime = 0;
+  thisuid = NULL;
+  for (uid = uidlist; uid; uid = uid->next)
+    {
+      if (!uid->mbox)
+        continue; /* Should not happen anyway.  */
+      if (policy->mailbox_only && ascii_strcasecmp (uid->uid, uid->mbox))
+        continue; /* UID has more than just the mailbox.  */
+      if (uid->created > thistime)
+        {
+          thistime = uid->created;
+          thisuid = uid;
+        }
+    }
+  if (!thisuid)
+    thisuid = uidlist;  /* This is the case for a missing timestamp.  */
+  if (opt.verbose)
+    log_info ("submitting key with user id '%s'\n", thisuid->uid);
+
+  /* If we have more than one user id we need to filter the key to
+   * include only THISUID.  */
+  if (uidlist->next)
+    {
+      estream_t newkey;
+
+      es_rewind (key);
+      err = wks_filter_uid (&newkey, key, thisuid->uid, 0);
+      if (err)
+        {
+          log_error ("error filtering key: %s\n", gpg_strerror (err));
+          err = gpg_error (GPG_ERR_NO_PUBKEY);
+          goto leave;
+        }
+      es_fclose (key);
+      key = newkey;
+    }
+
+  if (policy->mailbox_only
+      && (!thisuid->mbox || ascii_strcasecmp (thisuid->uid, thisuid->mbox)))
+    {
+      log_info ("Warning: policy requires 'mailbox-only'"
+                " - adding user id '%s'\n", addrspec);
+      err = add_user_id (fingerprint, addrspec);
+      if (err)
+        goto leave;
+
+      /* Need to get the key again.  This time we request filtering
+       * for the full user id, so that we do not need check and filter
+       * the key again.  */
+      es_fclose (key);
+      key = NULL;
+      err = wks_get_key (&key, fingerprint, addrspec, 1);
+      if (err)
+        goto leave;
+    }
+
+  /* Hack to support posteo but let them disable this by setting the
+   * new policy-version flag.  */
+  if (policy->protocol_version < 3
+      && !ascii_strcasecmp (domain, "posteo.de"))
+    {
+      log_info ("Warning: Using draft-1 method for domain '%s'\n", domain);
+      no_encrypt = 1;
+      posteo_hack = 1;
+    }
+
+  /* Encrypt the key part.  */
+  if (!no_encrypt)
+    {
+      es_rewind (key);
+      err = encrypt_response (&keyenc, key, submission_to, fingerprint);
+      if (err)
+        goto leave;
+      es_fclose (key);
+      key = NULL;
+    }
+
+  /* Send the key.  */
+  err = mime_maker_new (&mime, NULL);
+  if (err)
+    goto leave;
+  err = mime_maker_add_header (mime, "From", addrspec);
+  if (err)
+    goto leave;
+  err = mime_maker_add_header (mime, "To", submission_to);
+  if (err)
+    goto leave;
+  err = mime_maker_add_header (mime, "Subject", "Key publishing request");
+  if (err)
+    goto leave;
+
+  /* Tell server which draft we support.  */
+  err = mime_maker_add_header (mime, "Wks-Draft-Version",
+                                 STR2(WKS_DRAFT_VERSION));
+  if (err)
+    goto leave;
+
+  if (no_encrypt)
+    {
+      void *data;
+      size_t datalen, n;
+
+      if (posteo_hack)
+        {
+          /* Needs a multipart/mixed with one(!) attachment.  It does
+           * not grok a non-multipart mail.  */
+          err = mime_maker_add_header (mime, "Content-Type", "multipart/mixed");
+          if (err)
+            goto leave;
+          err = mime_maker_add_container (mime);
+          if (err)
+            goto leave;
+        }
+
+      err = mime_maker_add_header (mime, "Content-type",
+                                   "application/pgp-keys");
+      if (err)
+        goto leave;
+
+      if (es_fclose_snatch (key, &data, &datalen))
+        {
+          err = gpg_error_from_syserror ();
+          goto leave;
+        }
+      key = NULL;
+      /* We need to skip over the first line which has a content-type
+       * header not needed here.  */
+      for (n=0; n < datalen ; n++)
+        if (((const char *)data)[n] == '\n')
+          {
+            n++;
+            break;
+          }
+
+      err = mime_maker_add_body_data (mime, (char*)data + n, datalen - n);
+      xfree (data);
+      if (err)
+        goto leave;
+    }
+  else
+    {
+      err = mime_maker_add_header (mime, "Content-Type",
+                                   "multipart/encrypted; "
+                                   "protocol=\"application/pgp-encrypted\"");
+      if (err)
+        goto leave;
+      err = mime_maker_add_container (mime);
+      if (err)
+        goto leave;
+
+      err = mime_maker_add_header (mime, "Content-Type",
+                                   "application/pgp-encrypted");
+      if (err)
+        goto leave;
+      err = mime_maker_add_body (mime, "Version: 1\n");
+      if (err)
+        goto leave;
+      err = mime_maker_add_header (mime, "Content-Type",
+                                   "application/octet-stream");
+      if (err)
+        goto leave;
+
+      err = mime_maker_add_stream (mime, &keyenc);
+      if (err)
+        goto leave;
+    }
+
+  err = wks_send_mime (mime);
+
+ leave:
+  mime_maker_release (mime);
+  xfree (submission_to);
+  free_uidinfo_list (uidlist);
+  es_fclose (keyenc);
+  es_fclose (key);
+  wks_free_policy (policy);
+  xfree (policy);
+  xfree (addrspec);
+  return err;
+}
+
+
+
+static void
+encrypt_response_status_cb (void *opaque, const char *keyword, char *args)
+{
+  gpg_error_t *failure = opaque;
+  char *fields[2];
+
+  if (DBG_CRYPTO)
+    log_debug ("gpg status: %s %s\n", keyword, args);
+
+  if (!strcmp (keyword, "FAILURE"))
+    {
+      if (split_fields (args, fields, DIM (fields)) >= 2
+          && !strcmp (fields[0], "encrypt"))
+        *failure = strtoul (fields[1], NULL, 10);
+    }
+
+}
+
+
+/* Encrypt the INPUT stream to a new stream which is stored at success
+ * at R_OUTPUT.  Encryption is done for ADDRSPEC and for FINGERPRINT
+ * (so that the sent message may later be inspected by the user).  We
+ * currently retrieve that key from the WKD, DANE, or from "local".
+ * "local" is last to prefer the latest key version but use a local
+ * copy in case we are working offline.  It might be useful for the
+ * server to send the fingerprint of its encryption key - or even the
+ * entire key back.  */
+static gpg_error_t
+encrypt_response (estream_t *r_output, estream_t input, const char *addrspec,
+                  const char *fingerprint)
+{
+  gpg_error_t err;
+  ccparray_t ccp;
+  const char **argv;
+  estream_t output;
+  gpg_error_t gpg_err = 0;
+
+  *r_output = NULL;
+
+  output = es_fopenmem (0, "w+b");
+  if (!output)
+    {
+      err = gpg_error_from_syserror ();
+      log_error ("error allocating memory buffer: %s\n", gpg_strerror (err));
+      return err;
+    }
+
+  ccparray_init (&ccp, 0);
+
+  ccparray_put (&ccp, "--no-options");
+  if (!opt.verbose)
+    ccparray_put (&ccp, "--quiet");
+  else if (opt.verbose > 1)
+    ccparray_put (&ccp, "--verbose");
+  ccparray_put (&ccp, "--batch");
+  ccparray_put (&ccp, "--status-fd=2");
+  ccparray_put (&ccp, "--always-trust");
+  ccparray_put (&ccp, "--armor");
+  ccparray_put (&ccp, "-z0");  /* No compression for improved robustness.  */
+  if (fake_submission_addr)
+    ccparray_put (&ccp, "--auto-key-locate=clear,local");
+  else
+    ccparray_put (&ccp, "--auto-key-locate=clear,wkd,dane,local");
+  ccparray_put (&ccp, "--recipient");
+  ccparray_put (&ccp, addrspec);
+  ccparray_put (&ccp, "--recipient");
+  ccparray_put (&ccp, fingerprint);
+  ccparray_put (&ccp, "--encrypt");
+  ccparray_put (&ccp, "--");
+
+  ccparray_put (&ccp, NULL);
+  argv = ccparray_get (&ccp, NULL);
+  if (!argv)
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+  err = gnupg_exec_tool_stream (opt.gpg_program, argv, input,
+                                NULL, output,
+                                encrypt_response_status_cb, &gpg_err);
+  if (err)
+    {
+      if (gpg_err)
+        err = gpg_err;
+      log_error ("encryption failed: %s\n", gpg_strerror (err));
+      goto leave;
+    }
+
+  es_rewind (output);
+  *r_output = output;
+  output = NULL;
+
+ leave:
+  es_fclose (output);
+  xfree (argv);
+  return err;
+}
+
+
+static gpg_error_t
+send_confirmation_response (const char *sender, const char *address,
+                            const char *nonce, int encrypt,
+                            const char *fingerprint)
+{
+  gpg_error_t err;
+  estream_t body = NULL;
+  estream_t bodyenc = NULL;
+  mime_maker_t mime = NULL;
+
+  body = es_fopenmem (0, "w+b");
+  if (!body)
+    {
+      err = gpg_error_from_syserror ();
+      log_error ("error allocating memory buffer: %s\n", gpg_strerror (err));
+      return err;
+    }
+
+  /* It is fine to use 8 bit encoding because that is encrypted and
+   * only our client will see it.  */
+  if (encrypt)
+    {
+      es_fputs ("Content-Type: application/vnd.gnupg.wks\n"
+                "Content-Transfer-Encoding: 8bit\n"
+                "\n",
+                body);
+    }
+
+  es_fprintf (body, ("type: confirmation-response\n"
+                     "sender: %s\n"
+                     "address: %s\n"
+                     "nonce: %s\n"),
+              sender,
+              address,
+              nonce);
+
+  es_rewind (body);
+  if (encrypt)
+    {
+      err = encrypt_response (&bodyenc, body, sender, fingerprint);
+      if (err)
+        goto leave;
+      es_fclose (body);
+      body = NULL;
+    }
+
+  err = mime_maker_new (&mime, NULL);
+  if (err)
+    goto leave;
+  err = mime_maker_add_header (mime, "From", address);
+  if (err)
+    goto leave;
+  err = mime_maker_add_header (mime, "To", sender);
+  if (err)
+    goto leave;
+  err = mime_maker_add_header (mime, "Subject", "Key publication confirmation");
+  if (err)
+    goto leave;
+  err = mime_maker_add_header (mime, "Wks-Draft-Version",
+                               STR2(WKS_DRAFT_VERSION));
+  if (err)
+    goto leave;
+
+  if (encrypt)
+    {
+      err = mime_maker_add_header (mime, "Content-Type",
+                                   "multipart/encrypted; "
+                                   "protocol=\"application/pgp-encrypted\"");
+      if (err)
+        goto leave;
+      err = mime_maker_add_container (mime);
+      if (err)
+        goto leave;
+
+      err = mime_maker_add_header (mime, "Content-Type",
+                                   "application/pgp-encrypted");
+      if (err)
+        goto leave;
+      err = mime_maker_add_body (mime, "Version: 1\n");
+      if (err)
+        goto leave;
+      err = mime_maker_add_header (mime, "Content-Type",
+                                   "application/octet-stream");
+      if (err)
+        goto leave;
+
+      err = mime_maker_add_stream (mime, &bodyenc);
+      if (err)
+        goto leave;
+    }
+  else
+    {
+      err = mime_maker_add_header (mime, "Content-Type",
+                                   "application/vnd.gnupg.wks");
+      if (err)
+        goto leave;
+      err = mime_maker_add_stream (mime, &body);
+      if (err)
+        goto leave;
+    }
+
+  err = wks_send_mime (mime);
+
+ leave:
+  mime_maker_release (mime);
+  es_fclose (bodyenc);
+  es_fclose (body);
+  return err;
+}
+
+
+/* Reply to a confirmation request.  The MSG has already been
+ * decrypted and we only need to send the nonce back.  MAINFPR is
+ * either NULL or the primary key fingerprint of the key used to
+ * decrypt the request.  */
+static gpg_error_t
+process_confirmation_request (estream_t msg, const char *mainfpr)
+{
+  gpg_error_t err;
+  nvc_t nvc;
+  nve_t item;
+  const char *value, *sender, *address, *fingerprint, *nonce;
+
+  err = nvc_parse (&nvc, NULL, msg);
+  if (err)
+    {
+      log_error ("parsing the WKS message failed: %s\n", gpg_strerror (err));
+      goto leave;
+    }
+
+  if (DBG_MIME)
+    {
+      log_debug ("request follows:\n");
+      nvc_write (nvc, log_get_stream ());
+    }
+
+  /* Check that this is a confirmation request.  */
+  if (!((item = nvc_lookup (nvc, "type:")) && (value = nve_value (item))
+        && !strcmp (value, "confirmation-request")))
+    {
+      if (item && value)
+        log_error ("received unexpected wks message '%s'\n", value);
+      else
+        log_error ("received invalid wks message: %s\n", "'type' missing");
+      err = gpg_error (GPG_ERR_UNEXPECTED_MSG);
+      goto leave;
+    }
+
+  /* Get the fingerprint.  */
+  if (!((item = nvc_lookup (nvc, "fingerprint:"))
+        && (value = nve_value (item))
+        && strlen (value) >= 40))
+    {
+      log_error ("received invalid wks message: %s\n",
+                 "'fingerprint' missing or invalid");
+      err = gpg_error (GPG_ERR_INV_DATA);
+      goto leave;
+    }
+  fingerprint = value;
+
+  /* Check that the fingerprint matches the key used to decrypt the
+   * message.  In --read mode or with the old format we don't have the
+   * decryption key; thus we can't bail out.  */
+  if (!mainfpr || ascii_strcasecmp (mainfpr, fingerprint))
+    {
+      log_info ("target fingerprint: %s\n", fingerprint);
+      log_info ("but decrypted with: %s\n", mainfpr);
+      log_error ("confirmation request not decrypted with target key\n");
+      if (mainfpr)
+        {
+          err = gpg_error (GPG_ERR_INV_DATA);
+          goto leave;
+        }
+    }
+
+  /* Get the address.  */
+  if (!((item = nvc_lookup (nvc, "address:")) && (value = nve_value (item))
+        && is_valid_mailbox (value)))
+    {
+      log_error ("received invalid wks message: %s\n",
+                 "'address' missing or invalid");
+      err = gpg_error (GPG_ERR_INV_DATA);
+      goto leave;
+    }
+  address = value;
+  /* FIXME: Check that the "address" matches the User ID we want to
+   * publish.  */
+
+  /* Get the sender.  */
+  if (!((item = nvc_lookup (nvc, "sender:")) && (value = nve_value (item))
+        && is_valid_mailbox (value)))
+    {
+      log_error ("received invalid wks message: %s\n",
+                 "'sender' missing or invalid");
+      err = gpg_error (GPG_ERR_INV_DATA);
+      goto leave;
+    }
+  sender = value;
+  /* FIXME: Check that the "sender" matches the From: address.  */
+
+  /* Get the nonce.  */
+  if (!((item = nvc_lookup (nvc, "nonce:")) && (value = nve_value (item))
+        && strlen (value) > 16))
+    {
+      log_error ("received invalid wks message: %s\n",
+                 "'nonce' missing or too short");
+      err = gpg_error (GPG_ERR_INV_DATA);
+      goto leave;
+    }
+  nonce = value;
+
+  /* Send the confirmation.  If no key was found, try again without
+   * encryption.  */
+  err = send_confirmation_response (sender, address, nonce, 1, fingerprint);
+  if (gpg_err_code (err) == GPG_ERR_NO_PUBKEY)
+    {
+      log_info ("no encryption key found - sending response in the clear\n");
+      err = send_confirmation_response (sender, address, nonce, 0, NULL);
+    }
+
+ leave:
+  nvc_release (nvc);
+  return err;
+}
+
+
+/* Read a confirmation request and decrypt it if needed.  This
+ * function may not be used with a mail or MIME message but only with
+ * the actual encrypted or plaintext WKS data.  */
+static gpg_error_t
+read_confirmation_request (estream_t msg)
+{
+  gpg_error_t err;
+  int c;
+  estream_t plaintext = NULL;
+
+  /* We take a really simple approach to check whether MSG is
+   * encrypted: We know that an encrypted message is always armored
+   * and thus starts with a few dashes.  It is even sufficient to
+   * check for a single dash, because that can never be a proper first
+   * WKS data octet.  We need to skip leading spaces, though. */
+  while ((c = es_fgetc (msg)) == ' ' || c == '\t' || c == '\r' || c == '\n')
+    ;
+  if (c == EOF)
+    {
+      log_error ("can't process an empty message\n");
+      return gpg_error (GPG_ERR_INV_DATA);
+    }
+  if (es_ungetc (c, msg) != c)
+    {
+      log_error ("error ungetting octet from message\n");
+      return gpg_error (GPG_ERR_INTERNAL);
+    }
+
+  if (c != '-')
+    err = process_confirmation_request (msg, NULL);
+  else
+    {
+      struct decrypt_stream_parm_s decinfo;
+
+      err = decrypt_stream (&plaintext, &decinfo, msg);
+      if (err)
+        log_error ("decryption failed: %s\n", gpg_strerror (err));
+      else if (decinfo.otrust != 'u')
+        {
+          err = gpg_error (GPG_ERR_WRONG_SECKEY);
+          log_error ("key used to decrypt the confirmation request"
+                     " was not generated by us\n");
+        }
+      else
+        err = process_confirmation_request (plaintext, decinfo.mainfpr);
+      xfree (decinfo.fpr);
+      xfree (decinfo.mainfpr);
+    }
+
+  es_fclose (plaintext);
+  return err;
+}
+
+
+/* Called from the MIME receiver to process the plain text data in MSG.  */
+static gpg_error_t
+command_receive_cb (void *opaque, const char *mediatype,
+                    estream_t msg, unsigned int flags)
+{
+  gpg_error_t err;
+
+  (void)opaque;
+  (void)flags;
+
+  if (!strcmp (mediatype, "application/vnd.gnupg.wks"))
+    err = read_confirmation_request (msg);
+  else
+    {
+      log_info ("ignoring unexpected message of type '%s'\n", mediatype);
+      err = gpg_error (GPG_ERR_UNEXPECTED_MSG);
+    }
+
+  return err;
+}