[alt.security] NFS bug

emv@math.lsa.umich.edu (Edward Vielmetti) (06/03/90)

   >So - it's probably not a security hole that somebody is purposely trying
   >to take advantage of, but it is obvious to me that somebody has violated
   >security and written into a file on my directory where they do not have
   >write permission.

   No, no one has violated security.  This is the "confused file bug".
   It appears that the data structures in the kernel that keep track of
   which pages in memory are associated with which files are getting
   corrupted.  

A hack to cut down on the prevalence of this one is to mount file systems
with attribute caching times turned way down, i.e.

urania:/usr /n/urania/usr nfs 		ro,soft,bg,intr,actimeo=1,grpid 0 0
							^^^^^^^^^
This *seems* to have taken care of the problem here, or at least reduced its
frequency and severity.

--Ed

Edward Vielmetti, U of Michigan math dept.
emv@math.lsa.umich.edu