[PATCH] vt: detect and ignore OSC codes.

Adam Borowski
2014-01-15T07:01:06Z

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.

Not following Ecma-48, this commit recognizes 7-bit forms (ESC ] ... 0x07,
ESC ] .. ESC \) but not 8-bit (0x9D ... 0x9C).

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
---
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 61b1137..0377c52 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1590,7 +1590,7 @@ static void restore_cur(struct vc_data *vc)

enum { ESnormal, ESesc, ESsquare, ESgetpars, ESgotpars, 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)
@@ -1650,11 +1650,15 @@ 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:
@@ -1765,7 +1769,9 @@ 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:
@@ -2023,6 +2029,8 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
return;
default:
vc->vc_state = ESnormal;
+ case ESosc:
+ return;
}
}

--
1.8.5.2