[PATCH 23/48] tty: Clean console safely

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Petr PÃsaÅ <ppisar@xxxxxxxxxx>

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 <ppisar@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 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 a48da20..b3915b7 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;
-- 
1.7.4.2

--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux PPP]     [Linux FS]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Linmodem]     [Device Mapper]     [Linux Kernel for ARM]

  Powered by Linux