xref: /freebsd/crypto/openssh/contrib/gnome-ssh-askpass2.c (revision bc96366c864c07ef352edb92017357917c75b36c)
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 }
224