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From: machaffi@fred.cs.washington.edu (Scott MacHaffie)
Newsgroups: comp.lang.c
Subject: Re: Argument validity checking (addresses)
Keywords: address probing
Message-ID: <10603@june.cs.washington.edu>
Date: 5 Feb 90 03:54:42 GMT
References: <1990Jan18.175540.12131@wolves.uucp> <1009.nlhp3@oracle.nl> <10542@june.cs.washington.edu> <1990Feb3.052307.12524@wolves.uucp>
Sender: news@cs.washington.edu
Reply-To: machaffi@fred.cs.washington.edu.cs.washington.edu (Scott MacHaffie)
Organization: University of Washington
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In article <1990Feb3.052307.12524@wolves.uucp> ggw@wolves.UUCP (Gregory G. Woodbury) writes:
>The validity I was trying to insure was that the
>subroutine can pull bytes (or whatever) from the given address, or that
>the given address can be called as a function without *immediately* killing
>the process.

If you are expecting a function pointer and are passed a character pointer,
for example, then the process will probably die as soon as you call the
"function".  As an example, suppose that you are passed a pointer to
a character string which just happens to be the same as a function prolog
-- except that the first "instruction" is an illegal memory access.
Thus, the same problem returns for testing for valid function pointers.

			Scott MacHaffie