diff options
| author | Johan Hovold <johan@kernel.org> | 2021-04-07 13:23:29 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-14 10:44:11 +0300 |
| commit | ebb46274e33fa583447f3b9cbcba6f46397042de (patch) | |
| tree | 3bef0a9ac76ff37853f33f9f5ebd1e9a675a28b9 | |
| parent | d524fb44c657410535bbc8da17e5adae973c423f (diff) | |
| download | linux-ebb46274e33fa583447f3b9cbcba6f46397042de.tar.xz | |
tty: moxa: fix TIOCSSERIAL permission check
commit dc8c8437658667be9b11ec25c4b5482ed2becdaa upstream.
Changing the port close delay or type are privileged operations so make
sure to return -EPERM if a regular user tries to change them.
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407102334.32361-12-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/moxa.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/tty/moxa.c b/drivers/tty/moxa.c index 5fe0ca1457ca..1254b39074ed 100644 --- a/drivers/tty/moxa.c +++ b/drivers/tty/moxa.c @@ -2050,6 +2050,7 @@ static int moxa_set_serial_info(struct tty_struct *tty, struct serial_struct *ss) { struct moxa_port *info = tty->driver_data; + unsigned int close_delay; if (tty->index == MAX_PORTS) return -EINVAL; @@ -2061,19 +2062,24 @@ static int moxa_set_serial_info(struct tty_struct *tty, ss->baud_base != 921600) return -EPERM; + close_delay = msecs_to_jiffies(ss->close_delay * 10); + mutex_lock(&info->port.mutex); if (!capable(CAP_SYS_ADMIN)) { - if (((ss->flags & ~ASYNC_USR_MASK) != + if (close_delay != info->port.close_delay || + ss->type != info->type || + ((ss->flags & ~ASYNC_USR_MASK) != (info->port.flags & ~ASYNC_USR_MASK))) { mutex_unlock(&info->port.mutex); return -EPERM; } - } - info->port.close_delay = msecs_to_jiffies(ss->close_delay * 10); + } else { + info->port.close_delay = close_delay; - MoxaSetFifo(info, ss->type == PORT_16550A); + MoxaSetFifo(info, ss->type == PORT_16550A); - info->type = ss->type; + info->type = ss->type; + } mutex_unlock(&info->port.mutex); return 0; } |