From c12860c0f6e6b6b0301760a2b0e3e6b3f83eace8 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 7 Apr 2021 12:39:24 +0200 Subject: [PATCH] USB: serial: ftdi_sio: simplify TIOCGSERIAL permission check Changing the deprecated custom_divisor field is an unprivileged operation so after verifying that flag field does not contain any privileged changes both updates can be carried out by any user. Combine the two branches and drop the erroneous comment. Note that private flags field is only used for ASYNC flags so there's no need to try to retain any other bits when updating the flags. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold --- drivers/usb/serial/ftdi_sio.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 3fd7875..9228e56 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1496,27 +1496,16 @@ static int set_serial_info(struct tty_struct *tty, mutex_lock(&priv->cfg_lock); old_priv = *priv; - /* Do error checking and permission checking */ - if (!capable(CAP_SYS_ADMIN)) { if ((ss->flags ^ priv->flags) & ~ASYNC_USR_MASK) { mutex_unlock(&priv->cfg_lock); return -EPERM; } - priv->flags = ((priv->flags & ~ASYNC_USR_MASK) | - (ss->flags & ASYNC_USR_MASK)); - priv->custom_divisor = ss->custom_divisor; - goto check_and_exit; } - - /* Make the changes - these are privileged changes! */ - - priv->flags = ((priv->flags & ~ASYNC_FLAGS) | - (ss->flags & ASYNC_FLAGS)); + priv->flags = ss->flags & ASYNC_FLAGS; priv->custom_divisor = ss->custom_divisor; -check_and_exit: write_latency_timer(port); if ((priv->flags ^ old_priv.flags) & ASYNC_SPD_MASK || -- 2.7.4