contrib/gnome-ssh-askpass2.c

   1 /*
   2  * Copyright (c) 2000-2002 Damien Miller.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  18  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  19  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  20  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  22  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  23  */
  24
  25 /* GTK2 support by Nalin Dahyabhai <nalin@redhat.com> */
  26
  27 /*
  28  * This is a simple GNOME SSH passphrase grabber. To use it, set the
  29  * environment variable SSH_ASKPASS to point to the location of
  30  * gnome-ssh-askpass before calling "ssh-add < /dev/null".
  31  *
  32  * There is only two run-time options: if you set the environment variable
  33  * "GNOME_SSH_ASKPASS_GRAB_SERVER=true" then gnome-ssh-askpass will grab
  34  * the X server. If you set "GNOME_SSH_ASKPASS_GRAB_POINTER=true", then the
  35  * pointer will be grabbed too. These may have some benefit to security if
  36  * you don't trust your X server. We grab the keyboard always.
  37  */
  38
  39 #define GRAB_TRIES      16
  40 #define GRAB_WAIT       250 /* milliseconds */
  41
  42 /*
  43  * Compile with:
  44  *
  45  * cc -Wall `pkg-config --cflags gtk+-2.0` \
  46  *    gnome-ssh-askpass2.c -o gnome-ssh-askpass \
  47  *    `pkg-config --libs gtk+-2.0`
  48  *
  49  */
  50
  51 #include <stdlib.h>
  52 #include <stdio.h>
  53 #include <string.h>
  54 #include <unistd.h>
  55 #include <X11/Xlib.h>
  56 #include <gtk/gtk.h>
  57 #include <gdk/gdkx.h>
  58
  59 static void
  60 report_failed_grab (const char *what)
  61 {
  62         GtkWidget *err;
  63
  64         err = gtk_message_dialog_new(NULL, 0,
  65                                      GTK_MESSAGE_ERROR,
  66                                      GTK_BUTTONS_CLOSE,
  67                                      "Could not grab %s. "
  68                                      "A malicious client may be eavesdropping "
  69                                      "on your session.", what);
  70         gtk_window_set_position(GTK_WINDOW(err), GTK_WIN_POS_CENTER);
  71         gtk_label_set_line_wrap(GTK_LABEL((GTK_MESSAGE_DIALOG(err))->label),
  72                                 TRUE);
  73
  74         gtk_dialog_run(GTK_DIALOG(err));
  75
  76         gtk_widget_destroy(err);
  77 }
  78
  79 static void
  80 ok_dialog(GtkWidget *entry, gpointer dialog)
  81 {
  82         g_return_if_fail(GTK_IS_DIALOG(dialog));
  83         gtk_dialog_response(GTK_DIALOG(dialog), GTK_RESPONSE_OK);
  84 }
  85
  86 static int
  87 passphrase_dialog(char *message)
  88 {
  89         const char *failed;
  90         char *passphrase, *local;
  91         int result, grab_tries, grab_server, grab_pointer;
  92         GtkWidget *dialog, *entry;
  93         GdkGrabStatus status;
  94
  95         grab_server = (getenv("GNOME_SSH_ASKPASS_GRAB_SERVER") != NULL);
  96         grab_pointer = (getenv("GNOME_SSH_ASKPASS_GRAB_POINTER") != NULL);
  97         grab_tries = 0;
  98
  99         dialog = gtk_message_dialog_new(NULL, 0,
 100                                         GTK_MESSAGE_QUESTION,
 101                                         GTK_BUTTONS_OK_CANCEL,
 102                                         "%s",
 103                                         message);
 104
 105         entry = gtk_entry_new();
 106         gtk_box_pack_start(GTK_BOX(GTK_DIALOG(dialog)->vbox), entry, FALSE,
 107             FALSE, 0);
 108         gtk_entry_set_visibility(GTK_ENTRY(entry), FALSE);
 109         gtk_widget_grab_focus(entry);
 110         gtk_widget_show(entry);
 111
 112         gtk_window_set_title(GTK_WINDOW(dialog), "OpenSSH");
 113         gtk_window_set_position (GTK_WINDOW(dialog), GTK_WIN_POS_CENTER);
 114         gtk_window_set_keep_above(GTK_WINDOW(dialog), TRUE);
 115         gtk_label_set_line_wrap(GTK_LABEL((GTK_MESSAGE_DIALOG(dialog))->label),
 116                                 TRUE);
 117
 118         /* Make <enter> close dialog */
 119         gtk_dialog_set_default_response(GTK_DIALOG(dialog), GTK_RESPONSE_OK);
 120         g_signal_connect(G_OBJECT(entry), "activate",
 121                          G_CALLBACK(ok_dialog), dialog);
 122
 123         gtk_window_set_keep_above(GTK_WINDOW(dialog), TRUE);
 124
 125         /* Grab focus */
 126         gtk_widget_show_now(dialog);
 127         if (grab_pointer) {
 128                 for(;;) {
 129                         status = gdk_pointer_grab(
 130                            (GTK_WIDGET(dialog))->window, TRUE, 0, NULL,
 131                            NULL, GDK_CURRENT_TIME);
 132                         if (status == GDK_GRAB_SUCCESS)
 133                                 break;
 134                         usleep(GRAB_WAIT * 1000);
 135                         if (++grab_tries > GRAB_TRIES) {
 136                                 failed = "mouse";
 137                                 goto nograb;
 138                         }
 139                 }
 140         }
 141         for(;;) {
 142                 status = gdk_keyboard_grab((GTK_WIDGET(dialog))->window,
 143                    FALSE, GDK_CURRENT_TIME);
 144                 if (status == GDK_GRAB_SUCCESS)
 145                         break;
 146                 usleep(GRAB_WAIT * 1000);
 147                 if (++grab_tries > GRAB_TRIES) {
 148                         failed = "keyboard";
 149                         goto nograbkb;
 150                 }
 151         }
 152         if (grab_server) {
 153                 gdk_x11_grab_server();
 154         }
 155
 156         result = gtk_dialog_run(GTK_DIALOG(dialog));
 157
 158         /* Ungrab */
 159         if (grab_server)
 160                 XUngrabServer(GDK_DISPLAY());
 161         if (grab_pointer)
 162                 gdk_pointer_ungrab(GDK_CURRENT_TIME);
 163         gdk_keyboard_ungrab(GDK_CURRENT_TIME);
 164         gdk_flush();
 165
 166         /* Report passphrase if user selected OK */
 167         passphrase = g_strdup(gtk_entry_get_text(GTK_ENTRY(entry)));
 168         if (result == GTK_RESPONSE_OK) {
 169                 local = g_locale_from_utf8(passphrase, strlen(passphrase),
 170                                            NULL, NULL, NULL);
 171                 if (local != NULL) {
 172                         puts(local);
 173                         memset(local, '\0', strlen(local));
 174                         g_free(local);
 175                 } else {
 176                         puts(passphrase);
 177                 }
 178         }
 179
 180         /* Zero passphrase in memory */
 181         memset(passphrase, '\b', strlen(passphrase));
 182         gtk_entry_set_text(GTK_ENTRY(entry), passphrase);
 183         memset(passphrase, '\0', strlen(passphrase));
 184         g_free(passphrase);
 185
 186         gtk_widget_destroy(dialog);
 187         return (result == GTK_RESPONSE_OK ? 0 : -1);
 188
 189         /* At least one grab failed - ungrab what we got, and report
 190            the failure to the user.  Note that XGrabServer() cannot
 191            fail.  */
 192  nograbkb:
 193         gdk_pointer_ungrab(GDK_CURRENT_TIME);
 194  nograb:
 195         if (grab_server)
 196                 XUngrabServer(GDK_DISPLAY());
 197         gtk_widget_destroy(dialog);
 198
 199         report_failed_grab(failed);
 200
 201         return (-1);
 202 }
 203
 204 int
 205 main(int argc, char **argv)
 206 {
 207         char *message;
 208         int result;
 209
 210         gtk_init(&argc, &argv);
 211
 212         if (argc > 1) {
 213                 message = g_strjoinv(" ", argv + 1);
 214         } else {
 215                 message = g_strdup("Enter your OpenSSH passphrase:");
 216         }
 217
 218         setvbuf(stdout, 0, _IONBF, 0);
 219         result = passphrase_dialog(message);
 220         g_free(message);
 221
 222         return (result);
 223 }