linux/drivers/usb/class
Quentin Casasnovas da797a4ce5 cdc-acm: prevent infinite loop when parsing CDC headers.
[ Upstream commit 0d3bba0287 ]

Phil and I found out a problem with commit:

  7e860a6e7a ("cdc-acm: add sanity checks")

It added some sanity checks to ignore potential garbage in CDC headers but
also introduced a potential infinite loop.  This can happen at the first
loop iteration (elength = 0 in that case) if the description isn't a
DT_CS_INTERFACE or later if 'buffer[0]' is zero.

It should also be noted that the wrong length was being added to 'buffer'
in case 'buffer[1]' was not a DT_CS_INTERFACE descriptor, since elength was
assigned after that check in the loop.

A specially crafted USB device could be used to trigger this infinite loop.

Fixes: 7e860a6e7a ("cdc-acm: add sanity checks")
Signed-off-by: Phil Turnbull <phil.turnbull@oracle.com>
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
CC: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
CC: Oliver Neukum <oneukum@suse.de>
CC: Adam Lee <adam8157@gmail.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
History 2015-05-17 19:12:37 -04:00
..
cdc-acm.c cdc-acm: prevent infinite loop when parsing CDC headers. 2015-05-17 19:12:37 -04:00
cdc-acm.h USB: cdc-acm: add quirk for control-line state requests 2014-11-06 12:25:40 -08:00
cdc-wdm.c cdc-wdm: fix endianness bug in debug statements 2015-05-17 19:11:53 -04:00
Kconfig USB: regroup all depends on USB within an if USB block 2013-04-09 16:49:07 -07:00
Makefile USB: add USB test and measurement class driver 2008-10-17 14:40:51 -07:00
usblp.c usb: delete non-required instances of include <linux/init.h> 2014-01-08 15:01:39 -08:00
usbtmc.c usb: class: usbtmc.c: Cleaning up uninitialized variables 2014-07-09 15:59:10 -07:00