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 #define PROMPT_ENTRY 0
43 #define PROMPT_CONFIRM 1
44 #define PROMPT_NONE 2
45
46 /*
47 * Compile with:
48 *
49 * cc -Wall `pkg-config --cflags gtk+-2.0` \
50 * gnome-ssh-askpass2.c -o gnome-ssh-askpass \
51 * `pkg-config --libs gtk+-2.0`
52 *
53 */
54
55 #include <stdlib.h>
56 #include <stdio.h>
57 #include <string.h>
58 #include <unistd.h>
59
60 #include <X11/Xlib.h>
61 #include <gtk/gtk.h>
62 #include <gdk/gdkx.h>
63 #include <gdk/gdkkeysyms.h>
64
65 static void
ok_dialog(GtkWidget * entry,gpointer dialog)66 ok_dialog(GtkWidget *entry, gpointer dialog)
67 {
68 g_return_if_fail(GTK_IS_DIALOG(dialog));
69 gtk_dialog_response(GTK_DIALOG(dialog), GTK_RESPONSE_OK);
70 }
71
72 static gboolean
check_none(GtkWidget * widget,GdkEventKey * event,gpointer dialog)73 check_none(GtkWidget *widget, GdkEventKey *event, gpointer dialog)
74 {
75 switch (event->keyval) {
76 case GDK_KEY_Escape:
77 /* esc -> close dialog */
78 gtk_dialog_response(GTK_DIALOG(dialog), GTK_RESPONSE_CLOSE);
79 return TRUE;
80 case GDK_KEY_Tab:
81 /* tab -> focus close button */
82 gtk_widget_grab_focus(gtk_dialog_get_widget_for_response(
83 dialog, GTK_RESPONSE_CLOSE));
84 return TRUE;
85 default:
86 /* eat all other key events */
87 return TRUE;
88 }
89 }
90
91 static int
parse_env_hex_color(const char * env,GdkColor * c)92 parse_env_hex_color(const char *env, GdkColor *c)
93 {
94 const char *s;
95 unsigned long ul;
96 char *ep;
97 size_t n;
98
99 if ((s = getenv(env)) == NULL)
100 return 0;
101
102 memset(c, 0, sizeof(*c));
103
104 /* Permit hex rgb or rrggbb optionally prefixed by '#' or '0x' */
105 if (*s == '#')
106 s++;
107 else if (strncmp(s, "0x", 2) == 0)
108 s += 2;
109 n = strlen(s);
110 if (n != 3 && n != 6)
111 goto bad;
112 ul = strtoul(s, &ep, 16);
113 if (*ep != '\0' || ul > 0xffffff) {
114 bad:
115 fprintf(stderr, "Invalid $%s - invalid hex color code\n", env);
116 return 0;
117 }
118 /* Valid hex sequence; expand into a GdkColor */
119 if (n == 3) {
120 /* 4-bit RGB */
121 c->red = ((ul >> 8) & 0xf) << 12;
122 c->green = ((ul >> 4) & 0xf) << 12;
123 c->blue = (ul & 0xf) << 12;
124 } else {
125 /* 8-bit RGB */
126 c->red = ((ul >> 16) & 0xff) << 8;
127 c->green = ((ul >> 8) & 0xff) << 8;
128 c->blue = (ul & 0xff) << 8;
129 }
130 return 1;
131 }
132
133 static int
passphrase_dialog(char * message,int prompt_type)134 passphrase_dialog(char *message, int prompt_type)
135 {
136 const char *failed;
137 char *passphrase, *local;
138 int result, grab_tries, grab_server, grab_pointer;
139 int buttons, default_response;
140 GtkWidget *parent_window, *dialog, *entry, *err;
141 GdkGrabStatus status;
142 GdkColor fg, bg;
143 GdkSeat *seat;
144 GdkDisplay *display;
145 GdkSeatCapabilities caps;
146 int fg_set = 0, bg_set = 0;
147
148 grab_server = (getenv("GNOME_SSH_ASKPASS_GRAB_SERVER") != NULL);
149 grab_pointer = (getenv("GNOME_SSH_ASKPASS_GRAB_POINTER") != NULL);
150 grab_tries = 0;
151
152 fg_set = parse_env_hex_color("GNOME_SSH_ASKPASS_FG_COLOR", &fg);
153 bg_set = parse_env_hex_color("GNOME_SSH_ASKPASS_BG_COLOR", &bg);
154
155 /* Create an invisible parent window so that GtkDialog doesn't
156 * complain. */
157 parent_window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
158
159 switch (prompt_type) {
160 case PROMPT_CONFIRM:
161 buttons = GTK_BUTTONS_YES_NO;
162 default_response = GTK_RESPONSE_YES;
163 break;
164 case PROMPT_NONE:
165 buttons = GTK_BUTTONS_CLOSE;
166 default_response = GTK_RESPONSE_CLOSE;
167 break;
168 default:
169 buttons = GTK_BUTTONS_OK_CANCEL;
170 default_response = GTK_RESPONSE_OK;
171 break;
172 }
173
174 dialog = gtk_message_dialog_new(GTK_WINDOW(parent_window), 0,
175 GTK_MESSAGE_QUESTION, buttons, "%s", message);
176
177 gtk_window_set_title(GTK_WINDOW(dialog), "OpenSSH");
178 gtk_window_set_position (GTK_WINDOW(dialog), GTK_WIN_POS_CENTER);
179 gtk_window_set_keep_above(GTK_WINDOW(dialog), TRUE);
180 gtk_dialog_set_default_response(GTK_DIALOG(dialog), default_response);
181 gtk_window_set_keep_above(GTK_WINDOW(dialog), TRUE);
182
183 if (fg_set)
184 gtk_widget_modify_fg(dialog, GTK_STATE_NORMAL, &fg);
185 if (bg_set)
186 gtk_widget_modify_bg(dialog, GTK_STATE_NORMAL, &bg);
187
188 if (prompt_type == PROMPT_ENTRY || prompt_type == PROMPT_NONE) {
189 entry = gtk_entry_new();
190 if (fg_set)
191 gtk_widget_modify_fg(entry, GTK_STATE_NORMAL, &fg);
192 if (bg_set)
193 gtk_widget_modify_bg(entry, GTK_STATE_NORMAL, &bg);
194 gtk_box_pack_start(
195 GTK_BOX(gtk_dialog_get_content_area(GTK_DIALOG(dialog))),
196 entry, FALSE, FALSE, 0);
197 gtk_entry_set_visibility(GTK_ENTRY(entry), FALSE);
198 gtk_widget_grab_focus(entry);
199 if (prompt_type == PROMPT_ENTRY) {
200 gtk_widget_show(entry);
201 /* Make <enter> close dialog */
202 g_signal_connect(G_OBJECT(entry), "activate",
203 G_CALLBACK(ok_dialog), dialog);
204 } else {
205 /*
206 * Ensure the 'close' button is not focused by default
207 * but is still reachable via tab. This is a bit of a
208 * hack - it uses a hidden entry that responds to a
209 * couple of keypress events (escape and tab only).
210 */
211 gtk_widget_realize(entry);
212 g_signal_connect(G_OBJECT(entry), "key_press_event",
213 G_CALLBACK(check_none), dialog);
214 }
215 }
216 /* Grab focus */
217 gtk_widget_show_now(dialog);
218 display = gtk_widget_get_display(GTK_WIDGET(dialog));
219 seat = gdk_display_get_default_seat(display);
220 caps = GDK_SEAT_CAPABILITY_KEYBOARD;
221 if (grab_pointer)
222 caps |= GDK_SEAT_CAPABILITY_ALL_POINTING;
223 if (grab_server)
224 caps = GDK_SEAT_CAPABILITY_ALL;
225 for (;;) {
226 status = gdk_seat_grab(seat, gtk_widget_get_window(dialog),
227 caps, TRUE, NULL, NULL, NULL, NULL);
228 if (status == GDK_GRAB_SUCCESS)
229 break;
230 usleep(GRAB_WAIT * 1000);
231 if (++grab_tries > GRAB_TRIES)
232 goto nograb;
233 }
234
235 result = gtk_dialog_run(GTK_DIALOG(dialog));
236
237 /* Ungrab */
238 gdk_seat_ungrab(seat);
239 gdk_display_flush(display);
240
241 /* Report passphrase if user selected OK */
242 if (prompt_type == PROMPT_ENTRY) {
243 passphrase = g_strdup(gtk_entry_get_text(GTK_ENTRY(entry)));
244 if (result == GTK_RESPONSE_OK) {
245 local = g_locale_from_utf8(passphrase,
246 strlen(passphrase), NULL, NULL, NULL);
247 if (local != NULL) {
248 puts(local);
249 memset(local, '\0', strlen(local));
250 g_free(local);
251 } else {
252 puts(passphrase);
253 }
254 }
255 /* Zero passphrase in memory */
256 memset(passphrase, '\b', strlen(passphrase));
257 gtk_entry_set_text(GTK_ENTRY(entry), passphrase);
258 memset(passphrase, '\0', strlen(passphrase));
259 g_free(passphrase);
260 }
261
262 gtk_widget_destroy(dialog);
263 if (result != GTK_RESPONSE_OK && result != GTK_RESPONSE_YES)
264 return -1;
265 return 0;
266
267 nograb:
268 gtk_widget_destroy(dialog);
269 err = gtk_message_dialog_new(GTK_WINDOW(parent_window), 0,
270 GTK_MESSAGE_ERROR, GTK_BUTTONS_CLOSE,
271 "Could not grab input. A malicious client may be eavesdropping "
272 "on your session.");
273 gtk_window_set_position(GTK_WINDOW(err), GTK_WIN_POS_CENTER);
274 gtk_dialog_run(GTK_DIALOG(err));
275 gtk_widget_destroy(err);
276 return -1;
277 }
278
279 int
main(int argc,char ** argv)280 main(int argc, char **argv)
281 {
282 char *message, *prompt_mode;
283 int result, prompt_type = PROMPT_ENTRY;
284
285 gtk_init(&argc, &argv);
286
287 if (argc > 1) {
288 message = g_strjoinv(" ", argv + 1);
289 } else {
290 message = g_strdup("Enter your OpenSSH passphrase:");
291 }
292
293 if ((prompt_mode = getenv("SSH_ASKPASS_PROMPT")) != NULL) {
294 if (strcasecmp(prompt_mode, "confirm") == 0)
295 prompt_type = PROMPT_CONFIRM;
296 else if (strcasecmp(prompt_mode, "none") == 0)
297 prompt_type = PROMPT_NONE;
298 }
299
300 setvbuf(stdout, 0, _IONBF, 0);
301 result = passphrase_dialog(message, prompt_type);
302 g_free(message);
303
304 return (result);
305 }
306