gnome-ssh-askpass2.c revision c69db9c5a2d88a51f8d2394cf37717ba93f07152
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_label_set_line_wrap(GTK_LABEL((GTK_MESSAGE_DIALOG(dialog))->label),
115				TRUE);
116
117	/* Make <enter> close dialog */
118	gtk_dialog_set_default_response(GTK_DIALOG(dialog), GTK_RESPONSE_OK);
119	g_signal_connect(G_OBJECT(entry), "activate",
120			 G_CALLBACK(ok_dialog), dialog);
121
122	/* Grab focus */
123	gtk_widget_show_now(dialog);
124	if (grab_pointer) {
125		for(;;) {
126			status = gdk_pointer_grab(
127			   (GTK_WIDGET(dialog))->window, TRUE, 0, NULL,
128			   NULL, GDK_CURRENT_TIME);
129			if (status == GDK_GRAB_SUCCESS)
130				break;
131			usleep(GRAB_WAIT * 1000);
132			if (++grab_tries > GRAB_TRIES) {
133				failed = "mouse";
134				goto nograb;
135			}
136		}
137	}
138	for(;;) {
139		status = gdk_keyboard_grab((GTK_WIDGET(dialog))->window,
140		   FALSE, GDK_CURRENT_TIME);
141		if (status == GDK_GRAB_SUCCESS)
142			break;
143		usleep(GRAB_WAIT * 1000);
144		if (++grab_tries > GRAB_TRIES) {
145			failed = "keyboard";
146			goto nograbkb;
147		}
148	}
149	if (grab_server) {
150		gdk_x11_grab_server();
151	}
152
153	result = gtk_dialog_run(GTK_DIALOG(dialog));
154
155	/* Ungrab */
156	if (grab_server)
157		XUngrabServer(GDK_DISPLAY());
158	if (grab_pointer)
159		gdk_pointer_ungrab(GDK_CURRENT_TIME);
160	gdk_keyboard_ungrab(GDK_CURRENT_TIME);
161	gdk_flush();
162
163	/* Report passphrase if user selected OK */
164	passphrase = g_strdup(gtk_entry_get_text(GTK_ENTRY(entry)));
165	if (result == GTK_RESPONSE_OK) {
166		local = g_locale_from_utf8(passphrase, strlen(passphrase),
167					   NULL, NULL, NULL);
168		if (local != NULL) {
169			puts(local);
170			memset(local, '\0', strlen(local));
171			g_free(local);
172		} else {
173			puts(passphrase);
174		}
175	}
176
177	/* Zero passphrase in memory */
178	memset(passphrase, '\b', strlen(passphrase));
179	gtk_entry_set_text(GTK_ENTRY(entry), passphrase);
180	memset(passphrase, '\0', strlen(passphrase));
181	g_free(passphrase);
182
183	gtk_widget_destroy(dialog);
184	return (result == GTK_RESPONSE_OK ? 0 : -1);
185
186	/* At least one grab failed - ungrab what we got, and report
187	   the failure to the user.  Note that XGrabServer() cannot
188	   fail.  */
189 nograbkb:
190	gdk_pointer_ungrab(GDK_CURRENT_TIME);
191 nograb:
192	if (grab_server)
193		XUngrabServer(GDK_DISPLAY());
194	gtk_widget_destroy(dialog);
195
196	report_failed_grab(failed);
197
198	return (-1);
199}
200
201int
202main(int argc, char **argv)
203{
204	char *message;
205	int result;
206
207	gtk_init(&argc, &argv);
208
209	if (argc > 1) {
210		message = g_strjoinv(" ", argv + 1);
211	} else {
212		message = g_strdup("Enter your OpenSSH passphrase:");
213	}
214
215	setvbuf(stdout, 0, _IONBF, 0);
216	result = passphrase_dialog(message);
217	g_free(message);
218
219	return (result);
220}
221