Additionally (was Re: svn commit: r204803 - head/usr.bin/uniq)

[Andrey Chernov]

On Sun, Mar 07, 2010 at 02:52:11PM +0300, Andrey Chernov wrote:
> On Sun, Mar 07, 2010 at 12:46:27PM +0200, Jaakko Heinonen wrote:
> > On 2010-03-06, Andrey A. Chernov wrote:
> > >   3) Enforce the implied LINE_MAX limit (from POSIX definition of "text file"
> > >   and POSIX uniq(1) description).
> > 
> > Although a file with lines longer than LINE_MAX isn't a text file by
> > POSIX definition I don't think that POSIX requires uniq(1) to reject
> > non-POSIX text files. Thus I would like to keep the support for longer
> > lines.
> 
> Strictly speaking, POSIX says that uniq(1) (among others) supposed to work 
> with text files. Keeping it working with non-text ones too will be an 
> _extension_, not covered by POSIX.
> 
> But thinking about your suggestion the question immediately arises: how 
> much "longer lines"? say, up to 6x times? up part of memory avaliable? up 
> to size_t max? etc.
> 
> Any sort of limit still will remains the limit, but we already have POSIX 
> limit for that. I don't see much sense to replace one limit with the same 
> kind of it, but, say, 2x bigger.
> 
> Moreover, very big limits will cause security risk easily producing lack 
> of resources (memory).

If you feel that current LINE_MAX 2048 is too low limit, the proper fix 
will be to bump it, but allowing uncontrollable grown lines leads to 
denial-of-service attacks (not exhausted memory only but infinite swap 
too).

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