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
report_failed_grab(GtkWidget * parent_window,const char * what)60 report_failed_grab (GtkWidget *parent_window, const char *what)
61 {
62 GtkWidget *err;
63
64 err = gtk_message_dialog_new(GTK_WINDOW(parent_window), 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
72 gtk_dialog_run(GTK_DIALOG(err));
73
74 gtk_widget_destroy(err);
75 }
76
77 static void
ok_dialog(GtkWidget * entry,gpointer dialog)78 ok_dialog(GtkWidget *entry, gpointer dialog)
79 {
80 g_return_if_fail(GTK_IS_DIALOG(dialog));
81 gtk_dialog_response(GTK_DIALOG(dialog), GTK_RESPONSE_OK);
82 }
83
84 static int
passphrase_dialog(char * message)85 passphrase_dialog(char *message)
86 {
87 const char *failed;
88 char *passphrase, *local;
89 int result, grab_tries, grab_server, grab_pointer;
90 GtkWidget *parent_window, *dialog, *entry;
91 GdkGrabStatus status;
92
93 grab_server = (getenv("GNOME_SSH_ASKPASS_GRAB_SERVER") != NULL);
94 grab_pointer = (getenv("GNOME_SSH_ASKPASS_GRAB_POINTER") != NULL);
95 grab_tries = 0;
96
97 /* Create an invisible parent window so that GtkDialog doesn't
98 * complain. */
99 parent_window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
100
101 dialog = gtk_message_dialog_new(GTK_WINDOW(parent_window), 0,
102 GTK_MESSAGE_QUESTION,
103 GTK_BUTTONS_OK_CANCEL,
104 "%s",
105 message);
106
107 entry = gtk_entry_new();
108 gtk_box_pack_start(
109 GTK_BOX(gtk_dialog_get_content_area(GTK_DIALOG(dialog))), entry,
110 FALSE, FALSE, 0);
111 gtk_entry_set_visibility(GTK_ENTRY(entry), FALSE);
112 gtk_widget_grab_focus(entry);
113 gtk_widget_show(entry);
114
115 gtk_window_set_title(GTK_WINDOW(dialog), "OpenSSH");
116 gtk_window_set_position (GTK_WINDOW(dialog), GTK_WIN_POS_CENTER);
117 gtk_window_set_keep_above(GTK_WINDOW(dialog), TRUE);
118
119 /* Make <enter> close dialog */
120 gtk_dialog_set_default_response(GTK_DIALOG(dialog), GTK_RESPONSE_OK);
121 g_signal_connect(G_OBJECT(entry), "activate",
122 G_CALLBACK(ok_dialog), dialog);
123
124 gtk_window_set_keep_above(GTK_WINDOW(dialog), TRUE);
125
126 /* Grab focus */
127 gtk_widget_show_now(dialog);
128 if (grab_pointer) {
129 for(;;) {
130 status = gdk_pointer_grab(
131 (gtk_widget_get_window(GTK_WIDGET(dialog))), TRUE,
132 0, NULL, NULL, GDK_CURRENT_TIME);
133 if (status == GDK_GRAB_SUCCESS)
134 break;
135 usleep(GRAB_WAIT * 1000);
136 if (++grab_tries > GRAB_TRIES) {
137 failed = "mouse";
138 goto nograb;
139 }
140 }
141 }
142 for(;;) {
143 status = gdk_keyboard_grab(
144 gtk_widget_get_window(GTK_WIDGET(dialog)), FALSE,
145 GDK_CURRENT_TIME);
146 if (status == GDK_GRAB_SUCCESS)
147 break;
148 usleep(GRAB_WAIT * 1000);
149 if (++grab_tries > GRAB_TRIES) {
150 failed = "keyboard";
151 goto nograbkb;
152 }
153 }
154 if (grab_server) {
155 gdk_x11_grab_server();
156 }
157
158 result = gtk_dialog_run(GTK_DIALOG(dialog));
159
160 /* Ungrab */
161 if (grab_server)
162 XUngrabServer(gdk_x11_get_default_xdisplay());
163 if (grab_pointer)
164 gdk_pointer_ungrab(GDK_CURRENT_TIME);
165 gdk_keyboard_ungrab(GDK_CURRENT_TIME);
166 gdk_flush();
167
168 /* Report passphrase if user selected OK */
169 passphrase = g_strdup(gtk_entry_get_text(GTK_ENTRY(entry)));
170 if (result == GTK_RESPONSE_OK) {
171 local = g_locale_from_utf8(passphrase, strlen(passphrase),
172 NULL, NULL, NULL);
173 if (local != NULL) {
174 puts(local);
175 memset(local, '\0', strlen(local));
176 g_free(local);
177 } else {
178 puts(passphrase);
179 }
180 }
181
182 /* Zero passphrase in memory */
183 memset(passphrase, '\b', strlen(passphrase));
184 gtk_entry_set_text(GTK_ENTRY(entry), passphrase);
185 memset(passphrase, '\0', strlen(passphrase));
186 g_free(passphrase);
187
188 gtk_widget_destroy(dialog);
189 return (result == GTK_RESPONSE_OK ? 0 : -1);
190
191 /* At least one grab failed - ungrab what we got, and report
192 the failure to the user. Note that XGrabServer() cannot
193 fail. */
194 nograbkb:
195 gdk_pointer_ungrab(GDK_CURRENT_TIME);
196 nograb:
197 if (grab_server)
198 XUngrabServer(gdk_x11_get_default_xdisplay());
199 gtk_widget_destroy(dialog);
200
201 report_failed_grab(parent_window, failed);
202
203 return (-1);
204 }
205
206 int
main(int argc,char ** argv)207 main(int argc, char **argv)
208 {
209 char *message;
210 int result;
211
212 gtk_init(&argc, &argv);
213
214 if (argc > 1) {
215 message = g_strjoinv(" ", argv + 1);
216 } else {
217 message = g_strdup("Enter your OpenSSH passphrase:");
218 }
219
220 setvbuf(stdout, 0, _IONBF, 0);
221 result = passphrase_dialog(message);
222 g_free(message);
223
224 return (result);
225 }
226