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classic security mistake

One of the most obvious (and yet most common) computer security mistakes is to take input from an untrusted (and potentially hostile) source. A classic example of this is in Windows Vista where audio output from the system speakers can be taken as input to the speech recognition system. According to the BBC article an […]

ps and security

A post by Scott James Remnant describes how to hide command-line options from PS output. It’s handy to know that but that post made one significant implication that I strongly disagree with. It said about command-line parameters “perhaps they contain sensitive information“. If the parameters contain sensitive information then merely hiding them after the fact […]

core files

The issue of core file management has come up for discussion again in the SE Linux list.

I believe that there are two essential security requirements for managing core files, one is that the complete security context of the crashing process is stored (to the greatest possible extent), and the other is that processes with […]

more about vista security

While reading the discussion of Vista security on Bruce Schneier’s blog it occurred to me that comparing the issues of DRM that face MS with the issues faced by SE Linux developers provides some benefits.

SE Linux is designed to enable the owner of a computer to effectively enforce security policies to protect their system […]

DOSing Windows Vista

Chris Samual writes a good summary of Peter Gutmann’s analysis of the cost of Vista (in terms of DRM).

The following paragraph in the article however seemed more interesting to me: Once a weakness is found in a particular driver or device, that driver will have its signature revoked by Microsoft, which means that it […]

installing Debian Etch

A few days ago I installed Debian/Etch on my Thinkpad. One of the reasons for converting from Fedora to Debian is that I need to run Xen and Fedora doesn’t support non-PAE machines with Xen. Ironically it’s hardware supplied to me by Red Hat (Thinkpad T41p) that is lacks PAE support and forces me to […]

encryption speed – Debian vs Fedora

I’m in the process of converting my Fedora/rawhide laptop to Debian.

On Fedora the AES encrypted filesystems deliver about 38MB/s read speed according to dd. On Debian the speed is 2.4MB/s when running Xen and 2.7MB/s when not running Xen. The tests were done on the same block device.

Debian uses a SMP kernel (there […]

some questions about disk encryption

On a mailing list some questions were asked about disk encryption, I decided to blog the answer for the benefit of others: What type of encryption would be the strongest? the uncrackable if you will? im not interested in DES as this is a US govt recommendation – IDEA seems good but what kernel module […]

Debian SE Linux policy bug

checkmodule -m -o local.mod local.te semodule_package -o local.pp -m local.mod semodule -u local.pp

Save the following policy as local.te and then run the above commands to make semodule work correctly and to also allow restorecon to access the console on boot.

module local 1.0; require { class chr_file { read write }; class fd use; […]

SE Linux on Debian in 5 minutes

Following from my 5 minute OSDC talk yesterday on 5 security improvements needed in Linux distributions I gave a 5 minute talk on installing SE Linux on Debian etch. To display the notes I formatted them such that they were in 24 line pages and used less at a virtual console to display them. The […]