local denial of Service, Yellowdog linux to 3.0.1

[<pmoses@xxxxxxxxxxxxxxxx>]

Since they are releasing a new version....

Title: Local Denial of Service/render system unusable YelloDog Linux
Author: Phil Moses pmoses@xxxxxxxxxxxxxxxx
Date: June 4, 2004
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Summary:
Currently it seems that YellowDog is fairly easy to render unuseable, or what 
could be called launch a "local denial of service" on the operating system by 
filling the root disk to capacity and doing a "hard" reboot.
                                                                                
                               
                                                                                
                               
Description:
If the root filesystem is filled to capacity and the machine goes through an 
improper shutdown and is forced into an fsck, basically all hell breaks loose. 
It looks to me as if the file /etc/fstab attempts to write itself to a swap 
file and if the filesystem is full, replaces the original /etc/fstab with a 
zero sized file. It is possible to mount the root filesystem in rw mode and 
re-create the fstab file but until this is done, the system is not going to 
boot.
The YDL machines that I use are desktop machines that I have gathered for users 
and cannot be put under lock and key, meaning they could be unplugged at any 
time.
                                                                                
                               
Vulnerable Systems:
YDL 3.0.1 , possibly previous versions as well.