[PATCH v2] tty: Prevent hw state corruption in exclusive mode reopen

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

 



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 <shreyas.bethur@xxxxxx>
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
 drivers/tty/tty_io.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 4f35b43..51f066a 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__,
-- 
2.2.1

--
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