Disable window title reporting by default, since it's a security

hazard. I considered removing it completely, but I can't rule out
the possibility of an OS that actually takes security of its
terminal devices seriously, and which might be able to make sensible
and safe use of this feature.

git-svn-id: http://svn.tartarus.org/sgt/putty@3103 cda61777-01e9-0310-a592-d414129be87e

diff --git a/config.c b/config.c
index e8b7c579da1b2415f3d72e995f2867bca7d19bd8..58881ca35bd44dd5f4e77502c2289759d40d9562 100644 (file)
--- a/config.c
+++ b/config.c
@@ -1014,6 +1014,9 @@ void setup_config_box(struct controlbox *b, struct sesslist *sesslist,
                  HELPCTX(features_retitle),
                  dlg_stdcheckbox_handler,
                  I(offsetof(Config,no_remote_wintitle)));
+    ctrl_checkbox(s, "Disable remote window title querying (SECURITY)",
+                 'q', HELPCTX(features_qtitle), dlg_stdcheckbox_handler,
+                 I(offsetof(Config,no_remote_qtitle)));
     ctrl_checkbox(s, "Disable destructive backspace on server sending ^?",'b',
                  HELPCTX(features_dbackspace),
                  dlg_stdcheckbox_handler, I(offsetof(Config,no_dbackspace)));

diff --git a/doc/config.but b/doc/config.but
index 300b9efd6e0faf1f372049984062659ca755af21..fa70a09bd58dedc531b0a6720e9d8462bf7d8528 100644 (file)
--- a/doc/config.but
+++ b/doc/config.but
@@ -1,4 +1,4 @@
-\versionid $Id: config.but,v 1.61 2003/04/11 17:39:48 simon Exp $
+\versionid $Id: config.but,v 1.62 2003/04/12 08:59:06 simon Exp $
 
 \C{config} Configuring PuTTY
 
@@ -776,6 +776,26 @@ commands from the server. If you find PuTTY is doing this
 unexpectedly or inconveniently, you can tell PuTTY not to respond to
 those server commands.
 
+\S{config-features-qtitle} Disabling remote window title querying
+
+\cfg{winhelp-topic}{features.qtitle}
+
+PuTTY can optionally provide the xterm service of allowing server
+applications to find out the local window title. This feature is
+disabled by default, but you can turn it on if you really want it.
+
+NOTE that this feature is a \e{potential security hazard}. If a
+malicious application can write data to your terminal (for example,
+if you merely \c{cat} a file owned by someone else on the server
+machine), it can change your window title (unless you have disabled
+this as mentioned in \k{config-features-retitle}) and then use this
+service to have the new window title sent back to the server as if
+typed at the keyboard. This allows an attacker to fake keypresses
+and potentially cause your server-side applications to do things you
+didn't want. Therefore this feature is disabled by default, and we
+recommend you do not turn it on unless you \e{really} know what you
+are doing.
+
 \S{config-features-dbackspace} Disabling destructive backspace
 
 \cfg{winhelp-topic}{features.dbackspace}

diff --git a/putty.h b/putty.h
index a35bbc3e8dab738915d02dc76f5bd95290e27853..96447bc273627ccdc835b8dc2003433ff26c9695 100644 (file)
--- a/putty.h
+++ b/putty.h
@@ -378,6 +378,7 @@ struct config_tag {
     int no_remote_wintitle;           /* disable remote retitling */
     int no_dbackspace;                /* disable destructive backspace */
     int no_remote_charset;            /* disable remote charset config */
+    int no_remote_qtitle;             /* disable remote win title query */
     int app_cursor;
     int app_keypad;
     int nethack_keypad;

diff --git a/settings.c b/settings.c
index 1de8e51ae9163956e0f489ea2ed8a84322778e67..1152926cc62b26d4b7159174e7c4456bc2541dd8 100644 (file)
--- a/settings.c
+++ b/settings.c
@@ -240,6 +240,7 @@ void save_open_settings(void *sesskey, int do_host, Config *cfg)
     write_setting_i(sesskey, "NoRemoteResize", cfg->no_remote_resize);
     write_setting_i(sesskey, "NoAltScreen", cfg->no_alt_screen);
     write_setting_i(sesskey, "NoRemoteWinTitle", cfg->no_remote_wintitle);
+    write_setting_i(sesskey, "NoRemoteQTitle", cfg->no_remote_qtitle);
     write_setting_i(sesskey, "NoDBackspace", cfg->no_dbackspace);
     write_setting_i(sesskey, "NoRemoteCharset", cfg->no_remote_charset);
     write_setting_i(sesskey, "ApplicationCursorKeys", cfg->app_cursor);
@@ -472,6 +473,7 @@ void load_open_settings(void *sesskey, int do_host, Config *cfg)
     gppi(sesskey, "NoRemoteResize", 0, &cfg->no_remote_resize);
     gppi(sesskey, "NoAltScreen", 0, &cfg->no_alt_screen);
     gppi(sesskey, "NoRemoteWinTitle", 0, &cfg->no_remote_wintitle);
+    gppi(sesskey, "NoRemoteQTitle", 1, &cfg->no_remote_qtitle);
     gppi(sesskey, "NoDBackspace", 0, &cfg->no_dbackspace);
     gppi(sesskey, "NoRemoteCharset", 0, &cfg->no_remote_charset);
     gppi(sesskey, "ApplicationCursorKeys", 0, &cfg->app_cursor);

diff --git a/terminal.c b/terminal.c
index bcf202e515e1273bebe22699fc3f32c0b16ba6c3..aecef63992e817ed178c04b8e63f682e6647a33a 100644 (file)
--- a/terminal.c
+++ b/terminal.c
@@ -2604,7 +2604,8 @@ void term_out(Terminal *term)
                                 */
                                break;
                              case 20:
-                               if (term->ldisc) {
+                               if (term->ldisc &&
+                                   !term->cfg.no_remote_qtitle) {
                                    p = get_window_title(term->frontend, TRUE);
                                    len = strlen(p);
                                    ldisc_send(term->ldisc, "\033]L", 3, 0);
@@ -2613,7 +2614,8 @@ void term_out(Terminal *term)
                                }
                                break;
                              case 21:
-                               if (term->ldisc) {
+                               if (term->ldisc &&
+                                   !term->cfg.no_remote_qtitle) {
                                    p = get_window_title(term->frontend,FALSE);
                                    len = strlen(p);
                                    ldisc_send(term->ldisc, "\033]l", 3, 0);

diff --git a/winhelp.h b/winhelp.h
index d17db6b4762af74f96340b502bc5f397726bc8d5..e767aabc4cede5b97a6aa4e020d7f3b5b6b62840 100644 (file)
--- a/winhelp.h
+++ b/winhelp.h
@@ -26,6 +26,7 @@
 #define WINHELP_CTX_features_resize "features.resize"
 #define WINHELP_CTX_features_altscreen "features.altscreen"
 #define WINHELP_CTX_features_retitle "features.retitle"
+#define WINHELP_CTX_features_qtitle "features.qtitle"
 #define WINHELP_CTX_features_dbackspace "features.dbackspace"
 #define WINHELP_CTX_features_charset "features.charset"
 #define WINHELP_CTX_terminal_autowrap "terminal.autowrap"