From: Steve Holland <sdh4@iastate.edu>
Date: Thu, 18 Jun 2009 22:37:49 +0000 (-0500)
Subject: USB: usbtmc: inhibit corruption
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=92d07e422df3cc5370d0d9b95a671abb69d50ef1;p=linux-beck.git

USB: usbtmc: inhibit corruption

Limit data copied to userspace to amount requested.  Prevents a faulty
instrument from overwriting user memory.

Signed-off-by: Steve Holland <sdh4@iastate.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index f2fde7cd6109..91d3a94eeaa0 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -473,6 +473,10 @@ static ssize_t usbtmc_read(struct file *filp, char __user *buf,
 			n_characters = this_part;
 		}
 
+		/* Bound amount of data received by amount of data requested */
+		if (n_characters > this_part)
+			n_characters = this_part;
+
 		/* Copy buffer to user space */
 		if (copy_to_user(buf + done, &buffer[12], n_characters)) {
 			/* There must have been an addressing problem */