Re: clearenv(3): implies that it's a security tool

["Stéphane Aulery" <saulery-GANU6spQydw@public.gmane.org>]

tags 679323 + fixed-upstream
stop

-----

Will be fixed in man-pages-4.04.

See commit c66649c83598652222ff2a464e5b82284e6b1acf 
by Michael Kerrisk <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, 2016-02-19 12:04:51 (GMT)

https://git.kernel.org/cgit/docs/man-pages/man-pages.git/commit/man3/clearenv.3?id=c66649c83598652222ff2a464e5b82284e6b1acf



----- Matt Zimmerman <mdz-8fiUuRrzOP0dnm+yROfE0A@public.gmane.org> a écrit :
> On Fri, Feb 19, 2016 at 12:59:05PM +0100, Michael Kerrisk (man-pages) wrote:
> > On 18 February 2016 at 21:34, Matt Zimmerman <mdz-8fiUuRrzOP0dnm+yROfE0A@public.gmane.org> wrote:
> > > Thanks for following up.  My recommendation is to say something like:
> > >
> > > This function DOES NOT securely erase the contents of the environment.
> > > Security-conscious applications which need to do this should use ....
> > > instead.
> > 
> > So, I think this report is a little confused, but mainly because of
> > the poor description in the man page.
> > 
> > The security-conscious applications in this context are those that
> > want to precisely control the environment passed to an exec()ed
> > program. clearenv() cannot, indeed must not, try to erase the buffers
> > containing the environment definitions. (See putenv(3) to understand
> > why.) I've adjusted the man page in away that I hope explains things
> > better:
> > 
> >        The  clearenv()  function  may  be  useful  in security-conscious
> >        applications that want to precisely control the environment  that
> >        is  passed  to  programs executed using exec(3).  The application
> >        would do this by first clearing the environment and  then  adding
> >        select environment variables.
> > 
> >        Note that the main effect of clearenv() is to adjust the value of
> >        the pointer environ(7); this function does not erase the contents
> >        of the buffers containing the environment definitions.
> 
> Yes, that's much clearer, thank you!

Case classified, thank you for your help Matt and Michael!

Regards,

-- 
Stéphane Aulery
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