On 04/15/2011, 10:08 AM, 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 PÃsaÅ <[email protected]> > --- > drivers/tty/vt/vt.c | 7 +++++++ > 1 files changed, 7 insertions(+), 0 deletions(-) > > diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c > index 4bea1ef..cb661ca 100644 > --- a/drivers/tty/vt/vt.c > +++ b/drivers/tty/vt/vt.c > @@ -1197,6 +1197,13 @@ 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);
Why is here the division? I suppose this is superfluous, given scr_memsetw proper divides the size, hm? > + set_origin(vc); > + if (CON_IS_VISIBLE(vc)) > + update_screen(vc); > + /* fall through */ > case 2: /* erase whole display */ > count = vc->vc_cols * vc->vc_rows; > start = (unsigned short *)vc->vc_origin; > -- js
