kbx: Add framework for a public key daemon.

* kbx/keyboxd.c: New.
* kbx/keyboxd.h: New.
* kbx/kbxserver.c: New.
* kbx/keyboxd-w32info.rc: New.
* kbx/Makefile.am (EXTRA_DIST): Add new rc file.
(resource_objs): Ditto.
(libexec_PROGRAMS): New.
(common_libs, commonpth_libs): New.
(kbxutil_LDADD): Use here.
(keyboxd_SOURCES): New.
(keyboxd_CFLAGS): New.
(keyboxd_LDADD): New.
(keyboxd_LDFLAGS): New.
(keyboxd_DEPENDENCIES): new.
($(PROGRAMS)): Extend.

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 447 insertions, 0 deletions

diff --git a/kbx/kbxserver.c b/kbx/kbxserver.c
new file mode 100644
index 000000000..59fcb64c7
--- /dev/null
+++ b/kbx/kbxserver.c
@@ -0,0 +1,447 @@
+/* kbxserver.c - Handle Assuan commands send to the keyboxd
+ * Copyright (C) 2018 g10 Code GmbH
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ * SPDX-License-Identifier: GPL-3.0+
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <assert.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "keyboxd.h"
+#include <assuan.h>
+
+#include "../common/i18n.h"
+#include "../common/server-help.h"
+
+
+
+
+#define PARM_ERROR(t) assuan_set_error (ctx, \
+                                        gpg_error (GPG_ERR_ASS_PARAMETER), (t))
+#define set_error(e,t) (ctx ? assuan_set_error (ctx, gpg_error (e), (t)) \
+                        /**/: gpg_error (e))
+
+
+
+/* Control structure per connection. */
+struct server_local_s
+{
+  /* Data used to associate an Assuan context with local server data */
+  assuan_context_t assuan_ctx;
+
+  /* The session id (a counter).  */
+  unsigned int session_id;
+
+  /* If this flag is set to true this process will be terminated after
+   * the end of this session.  */
+  int stopme;
+
+  /* If the first both flags are set the assuan logging of data lines
+   * is suppressed.  The count variable is used to show the number of
+   * non-logged bytes.  */
+  size_t inhibit_data_logging_count;
+  unsigned int inhibit_data_logging : 1;
+  unsigned int inhibit_data_logging_now : 1;
+
+  /* Dummy option.  */
+  int foo;
+};
+
+
+
+
+/* Helper to print a message while leaving a command.  */
+static gpg_error_t
+leave_cmd (assuan_context_t ctx, gpg_error_t err)
+{
+  if (err)
+    {
+      const char *name = assuan_get_command_name (ctx);
+      if (!name)
+        name = "?";
+      if (gpg_err_source (err) == GPG_ERR_SOURCE_DEFAULT)
+        log_error ("command '%s' failed: %s\n", name,
+                   gpg_strerror (err));
+      else
+        log_error ("command '%s' failed: %s <%s>\n", name,
+                   gpg_strerror (err), gpg_strsource (err));
+    }
+  return err;
+}
+
+
+
+/* Handle OPTION commands. */
+static gpg_error_t
+option_handler (assuan_context_t ctx, const char *key, const char *value)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+  gpg_error_t err = 0;
+
+  if (!strcmp (key, "foo"))
+    {
+      ctrl->server_local->foo = 1;
+    }
+  else if (!strcmp (key, "lc-messages"))
+    {
+      if (ctrl->lc_messages)
+        xfree (ctrl->lc_messages);
+      ctrl->lc_messages = xtrystrdup (value);
+      if (!ctrl->lc_messages)
+        return out_of_core ();
+    }
+  else
+    err = gpg_error (GPG_ERR_UNKNOWN_OPTION);
+
+  return err;
+}
+
+
+
+static const char hlp_foo[] =
+  "FOO <user_id>\n"
+  "\n"
+  "Bla bla\n"
+  "more bla.";
+static gpg_error_t
+cmd_foo (assuan_context_t ctx, char *line)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+  gpg_error_t err;
+
+  (void)ctrl;
+  (void)line;
+
+  err = gpg_error (GPG_ERR_NOT_IMPLEMENTED);
+
+  return leave_cmd (ctx, err);
+}
+
+
+
+static const char hlp_getinfo[] =
+  "GETINFO <what>\n"
+  "\n"
+  "Multi purpose command to return certain information.  \n"
+  "Supported values of WHAT are:\n"
+  "\n"
+  "version     - Return the version of the program.\n"
+  "pid         - Return the process id of the server.\n"
+  "socket_name - Return the name of the socket.\n"
+  "session_id  - Return the current session_id.\n"
+  "getenv NAME - Return value of envvar NAME\n";
+static gpg_error_t
+cmd_getinfo (assuan_context_t ctx, char *line)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+  gpg_error_t err;
+  char numbuf[50];
+
+  if (!strcmp (line, "version"))
+    {
+      const char *s = VERSION;
+      err = assuan_send_data (ctx, s, strlen (s));
+    }
+  else if (!strcmp (line, "pid"))
+    {
+      snprintf (numbuf, sizeof numbuf, "%lu", (unsigned long)getpid ());
+      err = assuan_send_data (ctx, numbuf, strlen (numbuf));
+    }
+  else if (!strcmp (line, "socket_name"))
+    {
+      const char *s = get_kbxd_socket_name ();
+      if (!s)
+        s = "[none]";
+      err = assuan_send_data (ctx, s, strlen (s));
+    }
+  else if (!strcmp (line, "session_id"))
+    {
+      snprintf (numbuf, sizeof numbuf, "%u", ctrl->server_local->session_id);
+      err = assuan_send_data (ctx, numbuf, strlen (numbuf));
+    }
+  else if (!strncmp (line, "getenv", 6)
+           && (line[6] == ' ' || line[6] == '\t' || !line[6]))
+    {
+      line += 6;
+      while (*line == ' ' || *line == '\t')
+        line++;
+      if (!*line)
+        err = gpg_error (GPG_ERR_MISSING_VALUE);
+      else
+        {
+          const char *s = getenv (line);
+          if (!s)
+            err = set_error (GPG_ERR_NOT_FOUND, "No such envvar");
+          else
+            err = assuan_send_data (ctx, s, strlen (s));
+        }
+    }
+  else
+    err = set_error (GPG_ERR_ASS_PARAMETER, "unknown value for WHAT");
+
+  return leave_cmd (ctx, err);
+}
+
+
+
+static const char hlp_killkeyboxd[] =
+  "KILLKEYBOXD\n"
+  "\n"
+  "This command allows a user - given sufficient permissions -\n"
+  "to kill this keyboxd process.\n";
+static gpg_error_t
+cmd_killkeyboxd (assuan_context_t ctx, char *line)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+
+  (void)line;
+
+  ctrl->server_local->stopme = 1;
+  assuan_set_flag (ctx, ASSUAN_FORCE_CLOSE, 1);
+  return gpg_error (GPG_ERR_EOF);
+}
+
+
+static const char hlp_reloadkeyboxd[] =
+  "RELOADKEYBOXD\n"
+  "\n"
+  "This command is an alternative to SIGHUP\n"
+  "to reload the configuration.";
+static gpg_error_t
+cmd_reloadkeyboxd (assuan_context_t ctx, char *line)
+{
+  (void)ctx;
+  (void)line;
+
+  kbxd_sighup_action ();
+  return 0;
+}
+
+
+
+/* Tell the assuan library about our commands. */
+static int
+register_commands (assuan_context_t ctx)
+{
+  static struct {
+    const char *name;
+    assuan_handler_t handler;
+    const char * const help;
+  } table[] = {
+    { "FOO",        cmd_foo,        hlp_foo },
+    { "GETINFO",    cmd_getinfo,    hlp_getinfo },
+    { "KILLKEYBOXD",cmd_killkeyboxd,hlp_killkeyboxd },
+    { "RELOADKEYBOXD",cmd_reloadkeyboxd,hlp_reloadkeyboxd },
+    { NULL, NULL }
+  };
+  int i, j, rc;
+
+  for (i=j=0; table[i].name; i++)
+    {
+      rc = assuan_register_command (ctx, table[i].name, table[i].handler,
+                                    table[i].help);
+      if (rc)
+        return rc;
+    }
+  return 0;
+}
+
+
+/* Note that we do not reset the list of configured keyservers.  */
+static gpg_error_t
+reset_notify (assuan_context_t ctx, char *line)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+
+  (void)line;
+  (void)ctrl;
+
+  return 0;
+}
+
+
+/* This function is called by our assuan log handler to test whether a
+ * log message shall really be printed.  The function must return
+ * false to inhibit the logging of MSG.  CAT gives the requested log
+ * category.  MSG might be NULL. */
+int
+kbxd_assuan_log_monitor (assuan_context_t ctx, unsigned int cat,
+                         const char *msg)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+
+  (void)cat;
+  (void)msg;
+
+  if (!ctrl || !ctrl->server_local)
+    return 1; /* Can't decide - allow logging.  */
+
+  if (!ctrl->server_local->inhibit_data_logging)
+    return 1; /* Not requested - allow logging.  */
+
+  /* Disallow logging if *_now is true.  */
+  return !ctrl->server_local->inhibit_data_logging_now;
+}
+
+
+/* Return the assuan contxt from the local server info in CTRL.  */
+static assuan_context_t
+get_assuan_ctx_from_ctrl (ctrl_t ctrl)
+{
+  if (!ctrl || !ctrl->server_local)
+    return NULL;
+  return ctrl->server_local->assuan_ctx;
+}
+
+
+/* Startup the server and run the main command loop.  With FD = -1,
+ * use stdin/stdout.  SESSION_ID is either 0 or a unique number
+ * identifying a session. */
+void
+kbxd_start_command_handler (ctrl_t ctrl, gnupg_fd_t fd, unsigned int session_id)
+{
+  static const char hello[] = "Keyboxd " VERSION " at your service";
+  static char *hello_line;
+  int rc;
+  assuan_context_t ctx;
+
+  ctrl->server_local = xtrycalloc (1, sizeof *ctrl->server_local);
+  if (!ctrl->server_local)
+    {
+      log_error (_("can't allocate control structure: %s\n"),
+                 gpg_strerror (gpg_error_from_syserror ()));
+      xfree (ctrl);
+      return;
+    }
+
+  rc = assuan_new (&ctx);
+  if (rc)
+    {
+      log_error (_("failed to allocate assuan context: %s\n"),
+		 gpg_strerror (rc));
+      kbxd_exit (2);
+    }
+
+  if (fd == GNUPG_INVALID_FD)
+    {
+      assuan_fd_t filedes[2];
+
+      filedes[0] = assuan_fdopen (0);
+      filedes[1] = assuan_fdopen (1);
+      rc = assuan_init_pipe_server (ctx, filedes);
+    }
+  else
+    {
+      rc = assuan_init_socket_server (ctx, fd, ASSUAN_SOCKET_SERVER_ACCEPTED);
+    }
+
+  if (rc)
+    {
+      assuan_release (ctx);
+      log_error (_("failed to initialize the server: %s\n"),
+                 gpg_strerror (rc));
+      kbxd_exit (2);
+    }
+
+  rc = register_commands (ctx);
+  if (rc)
+    {
+      log_error (_("failed to the register commands with Assuan: %s\n"),
+                 gpg_strerror(rc));
+      kbxd_exit (2);
+    }
+
+
+  if (!hello_line)
+    {
+      hello_line = xtryasprintf
+        ("Home: %s\n"
+         "Config: %s\n"
+         "%s",
+         gnupg_homedir (),
+         /*opt.config_filename? opt.config_filename :*/ "[none]",
+         hello);
+    }
+
+  ctrl->server_local->assuan_ctx = ctx;
+  assuan_set_pointer (ctx, ctrl);
+
+  assuan_set_hello_line (ctx, hello_line);
+  assuan_register_option_handler (ctx, option_handler);
+  assuan_register_reset_notify (ctx, reset_notify);
+
+  ctrl->server_local->session_id = session_id;
+
+  /* The next call enable the use of status_printf.  */
+  set_assuan_context_func (get_assuan_ctx_from_ctrl);
+
+  for (;;)
+    {
+      rc = assuan_accept (ctx);
+      if (rc == -1)
+        break;
+      if (rc)
+        {
+          log_info (_("Assuan accept problem: %s\n"), gpg_strerror (rc));
+          break;
+        }
+
+#ifndef HAVE_W32_SYSTEM
+      if (opt.verbose)
+        {
+	  assuan_peercred_t peercred;
+
+          if (!assuan_get_peercred (ctx, &peercred))
+            log_info ("connection from process %ld (%ld:%ld)\n",
+                      (long)peercred->pid, (long)peercred->uid,
+		      (long)peercred->gid);
+        }
+#endif
+
+      rc = assuan_process (ctx);
+      if (rc)
+        {
+          log_info (_("Assuan processing failed: %s\n"), gpg_strerror (rc));
+          continue;
+        }
+    }
+
+
+  set_assuan_context_func (NULL);
+  ctrl->server_local->assuan_ctx = NULL;
+  assuan_release (ctx);
+
+  if (ctrl->server_local->stopme)
+    kbxd_exit (0);
+
+  if (ctrl->refcount)
+    log_error ("oops: connection control structure still referenced (%d)\n",
+               ctrl->refcount);
+  else
+    {
+      xfree (ctrl->server_local);
+      ctrl->server_local = NULL;
+    }
+}