From: ichudov@algebra.com (Igor Chudov @ home)
Date: Wed, 28 Aug 1996 04:42:29 +0800
To: adam@homeport.org (Adam Shostack)
Subject: Re: Code Review Guidelines (draft)
In-Reply-To: <199608270158.UAA24640@homeport.org>
Message-ID: <199608271620.LAA10933@manifold.algebra.com>
MIME-Version: 1.0
Content-Type: text


Adam Shostack wrote:
> 
> A few weeks back, I posted a request for source code review
> guidelines.  I got about 50 me-toos, but no guidelines.  So I wrote
> some I think are decent.  They're still in draft format.  I'd
> appreciate feedback & commentary on them.
> 
> http://www.homeport.org/~adam/review.html
> 

Thanks for an interesting paper.

In part " V.Code (Security Issues)/3.Data Checking" you say the following:

`` Data coming in to Acme Widgets should be checked very carefully for
        appropriateness. This check should be to see if the data is what
        is expected (length, characters). Making a list of bad
        characters is not the way to go; the lists are rarely complete.
        A secure program should know what it expects, and reject other
        input. (For example, if you are looking for an email address,
        don't check to see if it contains a semi-colon or a newline,
        check to see if it contains anything other than a [A-Za-z0-9._]
        followed by an @, followed by a hostname [A-Za-z0-9._].)''
END QUOTE

That is not entirely correct. An email address is much more than
that, it can contain "!", several "@" characters (not next to each other
though), "%", and so on. x400 mail addresses (?) can contain "/", "=",
and all emails can have "+" and "-" and "_" in them. 

Some of the valid email addresses are

user_name@company.com
alex+@pitt.edu
mi%aldan.UUCP@algebra.com
user%host.domain@anon.penet.fi
host1!host2!user

Look at your sendmail.cf file for a humongous amount of 
email parsing rules.

Thanks for an excellent document though, I put a link to it from my
intranet page.

	- Igor "Code Obscurity Creates Job Security" Chudov.