Date: Sat, 14 Jul 2007 00:24:33 +0400
From: Andrey Chernov <ache@nagual.pp.ru>
To: "Sean C. Farley" <scf@FreeBSD.org>
Cc: freebsd-current <freebsd-current@FreeBSD.org>
Subject: Re: Environment handling broken in /bin/sh with changes to {get,set,put}env()
Message-ID: <20070713202433.GA19856@nagual.pp.ru>
In-Reply-To: <20070713142545.K26096@thor.farley.org>
References: <20070705105922.F98700@thor.farley.org> <20070707130859.GA96605@nagual.pp.ru> <20070707131359.GB96605@nagual.pp.ru> <20070707133102.C14065@thor.farley.org> <20070707191835.GA4368@nagual.pp.ru> <20070707205410.B14065@thor.farley.org> <20070708020940.GA80166@nagual.pp.ru> <20070708171727.GA90490@nagual.pp.ru> <20070713162742.GA16260@nagual.pp.ru> <20070713142545.K26096@thor.farley.org>
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On Fri, Jul 13, 2007 at 02:39:30PM -0500, Sean C. Farley wrote:
> FreeBSD 6 will also dump if the length of the value was less than or
> equal to "/bin" since it reuses this string. This will core dump:
>
> nenv[0] = "PATH=/bin";
> nenv[1] = NULL;
> environ = nenv;
> setenv("PATH", "/bin", 1);
1) I care in first hand about unsetenv() as my example states. There
nowhere said in the specs that unsetenv() may modify environ _content_,
manpage says about pointers only.
2) That example not fail under FreeBSD 6 but fail under new code:
nenv[0] = "PATH=/bin";
nenv[1] = NULL;
environ = nenv;
setenv("HOME", "/xxx", 1);
(that is because new code will touch "PATH=/bin" string in anycase while
old ones looks for "HOME" only).
The most safest way is do not touch environ content outside of
scope of requested modification. That means I agree that
nenv[0] = "PATH=/bin";
setenv("PATH", "/bin", 1);
may fail, but not about the cases 1) and 2)
--
http://ache.pp.ru/
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