From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:41611 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751055AbbEIR00 (ORCPT ); Sat, 9 May 2015 13:26:26 -0400 Subject: Patch "cdc-acm: prevent infinite loop when parsing CDC headers." has been added to the 4.0-stable tree To: quentin.casasnovas@oracle.com, adam8157@gmail.com, gregkh@linuxfoundation.org, oneukum@suse.de, phil.turnbull@oracle.com, sergei.shtylyov@cogentembedded.com Cc: , From: Date: Sat, 09 May 2015 19:24:52 +0200 Message-ID: <1431192292148115@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled cdc-acm: prevent infinite loop when parsing CDC headers. to the 4.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: cdc-acm-prevent-infinite-loop-when-parsing-cdc-headers.patch and it can be found in the queue-4.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 0d3bba0287d4e284c3ec7d3397e81eec920d5e7e Mon Sep 17 00:00:00 2001 From: Quentin Casasnovas Date: Tue, 14 Apr 2015 11:25:43 +0200 Subject: cdc-acm: prevent infinite loop when parsing CDC headers. From: Quentin Casasnovas commit 0d3bba0287d4e284c3ec7d3397e81eec920d5e7e upstream. Phil and I found out a problem with commit: 7e860a6e7aa6 ("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: 7e860a6e7aa6 ("cdc-acm: add sanity checks") Signed-off-by: Phil Turnbull Signed-off-by: Quentin Casasnovas CC: Sergei Shtylyov CC: Oliver Neukum CC: Adam Lee Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1133,11 +1133,16 @@ static int acm_probe(struct usb_interfac } while (buflen > 0) { + elength = buffer[0]; + if (!elength) { + dev_err(&intf->dev, "skipping garbage byte\n"); + elength = 1; + goto next_desc; + } if (buffer[1] != USB_DT_CS_INTERFACE) { dev_err(&intf->dev, "skipping garbage\n"); goto next_desc; } - elength = buffer[0]; switch (buffer[2]) { case USB_CDC_UNION_TYPE: /* we've found it */ Patches currently in stable-queue which might be from quentin.casasnovas@oracle.com are queue-4.0/cdc-acm-prevent-infinite-loop-when-parsing-cdc-headers.patch