
Setuid Demystified [pdf] - lelf
http://www.cs.umd.edu/~jkatz/TEACHING/comp_sec_F04/downloads/setuid.pdf
======
voidz
This goes directly to the PDF. It seems to be a useful research paper for
people who want to get academic insights into setuid.

For those who would like to read the first part of the introduction, here it
is:

"Access control in Unix systems is mainly based on user IDs, yet the system
calls that modify user IDs (uid-setting system calls), such as setuid , are
poorly designed, insufficiently documented, and widely misunderstood and
misused. This has caused many security vulnerabilities in application
programs. We propose to make progress on the setuid mystery through two
approaches. First, we study kernel sources and compare the semantics of the
uid-setting system calls in three major Unix systems: Linux, Solaris, and
FreeBSD. Second, we develop a for- mal model of user IDs as a Finite State
Automaton (FSA) and develop new techniques for automatic construction of such
models."

For guys like me, the way this concept is explained and how it tackles the
supposed problem is a bit too difficult; it probably doesn't help that English
isn't my first language and that I'm not an academic.

The document also does not seem to contain a date of when it was written. Do I
need to figure this out on my own?

What would be nicer imo is if the poster can explain please, what makes this
paper qualify as 'news.' Why did it end up here? After all, well you know,
this place is called "Hacker News."

But even beyond that -- Understanding why this was posted could already
provide some useful context. Without that, when there's just a link (to a
PDF!), the effect it has on me is the same as those "link-only comments": 99%
of the time I skip right over them.

~~~
juhanima
Proceedings of the 11th USENIX Security Symposium Pages 171-190 USENIX
Association Berkeley, CA, USA ©2002

