FAILED: patch "[PATCH] staging: fwserial: fix TIOCSSERIAL permission check" failed to apply to 4.19-stable tree

PATCH [email protected] 1 participant 1 message May 12, 2021

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2021-05-12 08:31 UTC #0 lore raw

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2104eb283df66a482b60254299acbe3c68c03412 Mon Sep 17 00:00:00 2001
From: Johan Hovold <[email protected]>
Date: Wed, 7 Apr 2021 12:23:20 +0200
Subject: [PATCH] staging: fwserial: fix TIOCSSERIAL permission check

Changing the port close-delay parameter is a privileged operation so make sure to return -EPERM if a regular user tries to change it.

Fixes 7355ba3445f2 ("staging: fwserial: Add TTY-over-Firewire serial driver")

Cc [email protected] # 3.8

Signed-off-by Johan Hovold <[email protected]>

Link https://lore.kernel.org/r/[email protected] open here

Signed-off-by Greg Kroah-Hartman <[email protected]>

drivers/staging/fwserial/fwserial.c +6 -2

index c963848522b1..440d11423812 100644
@@ -1232,20 +1232,24 @@ static int set_serial_info(struct tty_struct *tty,
 			   struct serial_struct *ss)
 {
 	struct fwtty_port *port = tty->driver_data;
+	unsigned int cdelay;
 
 	if (ss->irq != 0 || ss->port != 0 || ss->custom_divisor != 0 ||
 	    ss->baud_base != 400000000)
 		return -EPERM;
 
+	cdelay = msecs_to_jiffies(ss->close_delay * 10);
+
 	mutex_lock(&port->port.mutex);
 	if (!capable(CAP_SYS_ADMIN)) {
-		if (((ss->flags & ~ASYNC_USR_MASK) !=
+		if (cdelay != port->port.close_delay ||
+		    ((ss->flags & ~ASYNC_USR_MASK) !=
 		     (port->port.flags & ~ASYNC_USR_MASK))) {
 			mutex_unlock(&port->port.mutex);
 			return -EPERM;
 		}
 	}
-	port->port.close_delay = msecs_to_jiffies(ss->close_delay * 10);
+	port->port.close_delay = cdelay;
 	mutex_unlock(&port->port.mutex);
 
 	return 0;