From 86f2c00f1d8e344965cf8df8572ed5f682956995 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Tue, 30 Dec 2014 10:39:25 -0500 Subject: tty: Prevent hw state corruption in exclusive mode reopen Exclusive mode ttys (TTY_EXCLUSIVE) do not allow further reopens; fail the condition before associating the file pointer and calling the driver open() method. Prevents DTR programming when the tty is already in exclusive mode. Reported-by: Shreyas Bethur Signed-off-by: Peter Hurley Acked-by: Shreyas Bethur Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 4f35b43e2475..51f066aa375e 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1464,6 +1464,9 @@ static int tty_reopen(struct tty_struct *tty) driver->subtype == PTY_TYPE_MASTER) return -EIO; + if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) + return -EBUSY; + tty->count++; WARN_ON(!tty->ldisc); @@ -2106,10 +2109,6 @@ retry_open: retval = -ENODEV; filp->f_flags = saved_flags; - if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && - !capable(CAP_SYS_ADMIN)) - retval = -EBUSY; - if (retval) { #ifdef TTY_DEBUG_HANGUP printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__, -- cgit v1.2.3-59-g8ed1b