Re: [PATCH] vt: detect and ignore OSC codes.

Greg Kroah-Hartman
2014-02-13T18:37:55Z

On Wed, Jan 15, 2014 at 07:21:04AM +0100, Adam Borowski wrote:
> 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>

Where is this documented?

> ---
> 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;

Why below the default: case?

thanks,

greg k-h