n_tty: Fix echo overrun tail computation
authorPeter Hurley <peter@hurleysoftware.com>
Fri, 8 Nov 2013 14:42:18 +0000 (09:42 -0500)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 25 Nov 2013 16:35:00 +0000 (08:35 -0800)
commit6f2225363c205e186c1465c2c7c84f17c1635504
tree21445d1f3e606048db55a3cb07e6bdcd8f5c8485
parent42458f41d08f0873299e830464c1232a6839297d
n_tty: Fix echo overrun tail computation

Commit cbfd0340ae1993378fd47179db949e050e16e697,
'n_tty: Process echoes in blocks', introduced an error when
consuming the echo buffer tail to prevent buffer overrun, where
the incorrect operation code byte is checked to determine how
far to advance the tail to the next echo byte.

Check the correct byte for the echo operation code byte.

Cc: <stable@vger.kernel.org> # 3.12.x : c476f65 tty: incorrect test of echo_buf() result for ECHO_OP_START
Cc: <stable@vger.kernel.org> # 3.12.x
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/n_tty.c