gnome-ssh-askpass2.c revision eb1a5f8de9f7ea602c373a710f531abbf81141c4
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 (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
79static void
80ok_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
86static int
87passphrase_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
204int
205main(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}
224