From 63f3a16db915096d7a80a96748adba00feb07a32 Mon Sep 17 00:00:00 2001 From: Adam Borowski Date: Wed, 19 Feb 2014 01:38:04 +0100 Subject: [PATCH] vt: detect and ignore OSC codes. 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 Signed-off-by: Greg Kroah-Hartman --- 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 b7bde54db138..3ad0b61e35b4 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; } -- 2.20.1