diff mbox series

[5.12,018/677] tty: mxser: fix TIOCSSERIAL permission check

Message ID 20210512144837.832252365@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman May 12, 2021, 2:41 p.m. UTC 
From: Johan Hovold <johan@kernel.org>

commit b91cfb2573aeb5ab426fc3c35bcfe9e0d2a7ecbc upstream.

Changing the port type and closing_wait parameter are privileged
operations so make sure to return -EPERM if a regular user tries to
change them.

Note that the closing_wait parameter would not actually have been
changed but the return value did not indicate that.

Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407102334.32361-15-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/mxser.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)
diff mbox series

Patch

--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -1270,6 +1270,7 @@  static int mxser_set_serial_info(struct
 	if (!capable(CAP_SYS_ADMIN)) {
 		if ((ss->baud_base != info->baud_base) ||
 				(close_delay != info->port.close_delay) ||
+				(closing_wait != info->port.closing_wait) ||
 				((ss->flags & ~ASYNC_USR_MASK) != (info->port.flags & ~ASYNC_USR_MASK))) {
 			mutex_unlock(&port->mutex);
 			return -EPERM;
@@ -1296,11 +1297,11 @@  static int mxser_set_serial_info(struct
 			baud = ss->baud_base / ss->custom_divisor;
 			tty_encode_baud_rate(tty, baud, baud);
 		}
-	}
 
-	info->type = ss->type;
+		info->type = ss->type;
 
-	process_txrx_fifo(info);
+		process_txrx_fifo(info);
+	}
 
 	if (tty_port_initialized(port)) {
 		if (flags != (port->flags & ASYNC_SPD_MASK)) {