Bugtraq: Re: imapd/ipop3d coredump - the patch.

[mikedoug () TEXAS NET (Michael Douglass)]

On Thu, Feb 05, 1998 at 09:45:38AM +0200, raf () licj      (Bugtraq Mirror) said:

> -  if (!(pw && pw->pw_uid)) return NIL;
> +  if (!(pw)) return NIL;
> +  if (!(pw->pw_uid)) return NIL;
> ... why do we need "optimisations" when authentificating users ???? :)
> and btw: in original version root was still able to log in...
You are very incorrect here.  Both your version and the original
version do the exact same thing:  If pw = valid_addr && pw->pw_uid
= 0 then it would return NIL; which would deny root.

However, the _readable_ way to write this would be:

if( !pw || !pw->pw_uid ) return NIL;

This stops if pw is not valid or if pw->pw_uid is 0.  This is exactly
the same as the frist statement since:

!(A && B)  == !A || !B

...only much more readable.

--
Michael Douglass
Texas Networking, Inc.

<tnet admin> anyway, I'm off, perl code is making me [a] crosseyed toady