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tty: fix return value for unsupported ioctls

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[ Upstream commit 1b8b20868a6d64cfe8174a21b25b74367bdf0560 ]

Drivers should return -ENOTTY ("Inappropriate I/O control operation")
when an ioctl isn't supported, while -EINVAL is used for invalid
arguments.

Fix up the TIOCMGET, TIOCMSET and TIOCGICOUNT helpers which returned
-EINVAL when a tty driver did not implement the corresponding
operations.

Note that the TIOCMGET and TIOCMSET helpers predate git and do not get a
corresponding Fixes tag below.

Fixes: d281da7ff6f7 ("tty: Make tiocgicount a handler")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407095208.31838-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Johan Hovold 2021-04-07 11:52:02 +02:00 committed by Greg Kroah-Hartman
parent 6f1a2aa411
commit 2707118bae
2 changed files with 5 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/tty/tty_io.c
View File

@ -2791,14 +2791,14 @@ out:
* @p: pointer to result
*
* Obtain the modem status bits from the tty driver if the feature
* is supported. Return -EINVAL if it is not available.
* is supported. Return -ENOTTY if it is not available.
*
* Locking: none (up to the driver)
*/
static int tty_tiocmget(struct tty_struct *tty, int __user *p)
{
int retval = -EINVAL;
int retval = -ENOTTY;
if (tty->ops->tiocmget) {
retval = tty->ops->tiocmget(tty);
@ -2816,7 +2816,7 @@ static int tty_tiocmget(struct tty_struct *tty, int __user *p)
* @p: pointer to desired bits
*
* Set the modem status bits from the tty driver if the feature
* is supported. Return -EINVAL if it is not available.
* is supported. Return -ENOTTY if it is not available.
*
* Locking: none (up to the driver)
*/
@ -2828,7 +2828,7 @@ static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
unsigned int set, clear, val;
if (tty->ops->tiocmset == NULL)
return -EINVAL;
return -ENOTTY;
retval = get_user(val, p);
if (retval)

2
include/linux/tty_driver.h
View File

@ -235,7 +235,7 @@
*
* Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
* structure to complete. This method is optional and will only be called
* if provided (otherwise EINVAL will be returned).
* if provided (otherwise ENOTTY will be returned).
*/
#include <linux/export.h>