[PATCH] [RHEL/6] Search for nousb kernel command line argument in /etc/grub.conf within bootloader_nousb_argument check case-insensitively
Trey Henefield
trey.henefield at ultra-ats.com
Thu Apr 17 19:20:50 UTC 2014
We have a mix a systems to which some require USB and some do not. While it’s not feasible to know the need of every system when applying this requirement, I have found some logic that seems to work:
USB_DEVICE=$(grep 'Product=' /proc/bus/usb/devices | egrep -ic '(ps2 to usb adapter|keyboard|kvm|sc reader)')
If [ $USB_DEVICE = 0 ]; then
DO SOME ACTION
fi
The above will check for a USB keyboard, a PS2 to USB adapter (needed for a USB keyboard in some cases), a USB KVM, and a CAC reader (only approved versions are USB).
It may be useful to add that logic to your fix.
Best regards,
Trey Henefield, CISSP
Senior IAVA Engineer
Ultra Electronics
Advanced Tactical Systems, Inc.
4101 Smith School Road
Building IV, Suite 100
Austin, TX 78744 USA
Trey.Henefield at ultra-ats.com
Tel: +1 512 327 6795 ext. 647
Fax: +1 512 327 8043
Mobile: +1 512 541 6450
www.ultra-ats.com
From: scap-security-guide-bounces at lists.fedorahosted.org [mailto:scap-security-guide-bounces at lists.fedorahosted.org] On Behalf Of Trevor Vaughan
Sent: Thursday, April 17, 2014 7:11 AM
To: SCAP Security Guide
Subject: Re: [PATCH] [RHEL/6] Search for nousb kernel command line argument in /etc/grub.conf within bootloader_nousb_argument check case-insensitively
Just out of curiosity, is adding nousb to the grub command line actually feasible for enforcement?
I can't remember the last time I used a system where I didn't need a USB keyboard at some point (can you even buy server class systems with PS/2 support any more?)
Trevor
On Wed, Apr 16, 2014 at 8:23 PM, Shawn Wells <shawn at redhat.com><mailto:shawn at redhat.com>> wrote:
On 4/16/14, 5:08 PM, Kayse, Josh wrote:
On Apr 16, 2014, at 8:06 PM, Kayse, Josh <Joshua.Kayse at gtri.gatech.edu><mailto:Joshua.Kayse at gtri.gatech.edu>> wrote:
On Apr 16, 2014, at 7:59 PM, Shawn Wells <shawn at redhat.com><mailto:shawn at redhat.com>> wrote:
On 4/16/14, 5:44 AM, Jan Lieskovsky wrote:
Patch summary:
* check for 'nousb' argument on kernel command line in /etc/grub.conf
within the bootloader_nousb_argument check in a case-insensitive way
* update comments where appropriate
* add test attestation timestamp
* replace path + filename ind construct with filepath one
Testing report:
* Tested on RHEL-6. Works fine.
I wasn't sure if nousb was case insensitive, so I checked https://www.kernel.org/doc/Documentation/kernel-parameters.txt
And found this:
Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
a trailing = on the name of any parameter states that that parameter will
be entered as an environment variable, whereas its absence indicates that
it will appear as a kernel argument readable via /proc/cmdline by programs
running once the system is up.
"nousb" was in the list as case sensitive.
Applied your patch (RHEL 6.5), added "nOuSB," and things seem to check out. Should we follow the kernel docs (which say case sensitive), or allow insensitivity since it actually works?
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I’d like to point out that the selinux parameter is also within that list. I vote we should follow what actually works and assume the kernel docs are out of date.
-josh
Also, according to https://github.com/torvalds/linux/blame/master/Documentation/kernel-parameters.txt that line was last changed 2005. Perhaps someone should brave lkml and submit a patch.
-josh
Thanks for that link!
Ack to Jan's patch.
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Trevor Vaughan
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