Xref: utzoo comp.sources.bugs:1390 comp.bugs.sys5:695
Path: utzoo!attcan!uunet!pyrdc!pyrnj!rutgers!columbia!douglass!dupuy
From: dupuy@douglass.columbia.edu (Alexander Dupuy)
Newsgroups: comp.sources.bugs,comp.bugs.sys5
Subject: Re: v05i028: /etc/magic lines for compress
Summary: you can crash file with misaligned magic
Message-ID: <6029@columbia.edu>
Date: 17 Nov 88 18:53:42 GMT
References: <1033@investor.UUCP> <454@auspex.UUCP> <7714@boring.cwi.nl> <6021@columbia.edu>
Sender: news@columbia.edu
Reply-To: dupuy@douglass.columbia.edu (Alexander Dupuy)
Followup-To: comp.sources.bugs
Organization: Columbia University Computer Science Dept.
Lines: 17


Just to follow up on the problems with /etc/magic formats: it is currently
possible to cause file(1) to crash on a Sparc (or other strict alignment
machine) by having magic entries which are of type "short" or "long", at
misaligned offsets.  If you have a Sun-2 or Sun-4, you can repeat this by
placing the following entry into /etc/magic:

1	long		0		doesn't matter if it matches or not.

This should crash file with a Bus Error, when you apply it to any file for
which it doesn't have a builtin rule, such as an ordinary ASCII text file.

@alex

-- 
inet: dupuy@columbia.edu
uucp: ...!rutgers!columbia!dupuy