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authorPetr Písař <ppisar@redhat.com>2011-04-15 10:08:08 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-19 16:33:37 -0700
commitf8df13e0a901fe55631fed66562369b4dba40f8b (patch)
tree105031898b999a9da275a7aa32b5d67733d5b849 /drivers/tty/vt
parentd94206028854ba4c891004cecdbb2e220bf277bb (diff)
downloadlinux-f8df13e0a901fe55631fed66562369b4dba40f8b.tar.bz2
tty: Clean console safely
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/tty/vt')
-rw-r--r--drivers/tty/vt/vt.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index a48da2063060..b3915b7ad3e2 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1193,6 +1193,13 @@ 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);
+ 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;