lkml.org 
[lkml]   [2011]   [Apr]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] Clean console safely
Date
Hi,

On Wed, Apr 13 2011, Petr Písař wrote:
> Traditional \E[2J sequence erases console display but scroll-back
> buffer and underlying device (frame) buffer keep data that can be
> accessed by scrolling console back.
>
> This patch introduce new \E[J parameter 3 that allows to scramble
> scroll-back buffer explicitly. Session locking programs (screen,
> vlock) can use it to prevent attacker to browse locked console
> history.
>
> Signed-off-by: Petr Písař <ppisar@redhat.com>
> ---
> drivers/tty/vt/vt.c | 6 ++++++
> 1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
> index 4bea1ef..fe96a1f 100644
> --- a/drivers/tty/vt/vt.c
> +++ b/drivers/tty/vt/vt.c
> @@ -1197,6 +1197,12 @@ static void csi_J(struct vc_data *vc, int vpar)
> vc->vc_x + 1);
> }
> break;
> + case 3: /* erase scroll-back buffer (and whole display) */
> + scr_memsetw(vc->vc_screenbuf, vc->vc_video_erase_char,
> + vc->vc_screenbuf_size >> 1);
> + set_origin(vc);
> + if (CON_IS_VISIBLE(vc))
> + update_screen(vc);
> case 2: /* erase whole display */
> count = vc->vc_cols * vc->vc_rows;
> start = (unsigned short *)vc->vc_origin;

Nitpick: the cases were ordered before -- 3 should go after 2.

- Chris.
--
Chris Ball <cjb@laptop.org> <http://printf.net/>
One Laptop Per Child
--
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/

\
 
 \ /
  Last update: 2011-04-13 17:15    [W:0.052 / U:1.612 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site