Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752064AbaBSAib (ORCPT ); Tue, 18 Feb 2014 19:38:31 -0500 Received: from tartarus.angband.pl ([89.206.35.136]:53444 "EHLO tartarus.angband.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751435AbaBSAi3 (ORCPT ); Tue, 18 Feb 2014 19:38:29 -0500 From: Adam Borowski To: Greg Kroah-Hartman , Jiri Slaby , linux-kernel@vger.kernel.org Cc: Adam Borowski Date: Wed, 19 Feb 2014 01:38:04 +0100 Message-Id: <1392770284-6890-1-git-send-email-kilobyte@angband.pl> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140218184430.GA29209@kroah.com> References: <20140218184430.GA29209@kroah.com> X-SA-Exim-Connect-IP: 2001:6a0:118::6 X-SA-Exim-Mail-From: kilobyte@angband.pl Subject: [PATCH] vt: detect and ignore OSC codes. X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on tartarus.angband.pl) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org These can be used to send commands consisting of an arbitrary string to the terminal, most often used to set a terminal's window title or to redefine the colour palette. Our console doesn't use OSC, unlike everything else, which can lead to junk being displayed if a process sends such a code unconditionally. The rules for termination follow established practice rather than Ecma-48. Ecma-48 requires the string to use only byte values 0x08..0x0D and 0x20..0x7E, terminated with either ESC \ or 0x9C. This would disallow using 8-bit characters, which are reasonable for example in window titles. A widespread idiom is to terminate with 0x07. The behaviour for other control characters differs between terminal emulators, I followed libvte and xterm: * 0x07 and ESC anything terminate * nothing else terminates, all 8-bit values including 0x9C are considered a part of the string Signed-off-by: Adam Borowski --- drivers/tty/vt/vt.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index b7bde54..3ad0b61 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -1592,7 +1592,7 @@ static void restore_cur(struct vc_data *vc) enum { ESnormal, ESesc, ESsquare, ESgetpars, ESfunckey, EShash, ESsetG0, ESsetG1, ESpercent, ESignore, ESnonstd, - ESpalette }; + ESpalette, ESosc }; /* console_lock is held (except via vc_init()) */ static void reset_terminal(struct vc_data *vc, int do_clear) @@ -1652,11 +1652,15 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) * Control characters can be used in the _middle_ * of an escape sequence. */ + if (vc->vc_state == ESosc && c>=8 && c<=13) /* ... except for OSC */ + return; switch (c) { case 0: return; case 7: - if (vc->vc_bell_duration) + if (vc->vc_state == ESosc) + vc->vc_state = ESnormal; + else if (vc->vc_bell_duration) kd_mksound(vc->vc_bell_pitch, vc->vc_bell_duration); return; case 8: @@ -1767,7 +1771,9 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) } else if (c=='R') { /* reset palette */ reset_palette(vc); vc->vc_state = ESnormal; - } else + } else if (c>='0' && c<='9') + vc->vc_state = ESosc; + else vc->vc_state = ESnormal; return; case ESpalette: @@ -2021,6 +2027,8 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) vc->vc_translate = set_translate(vc->vc_G1_charset, vc); vc->vc_state = ESnormal; return; + case ESosc: + return; default: vc->vc_state = ESnormal; } -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/