gnome-ssh-askpass2.c revision 323134 
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
59static void
60report_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
77static void
78ok_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
84static int
85passphrase_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
206int
207main(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