From: Jilles Tjoelker <jilles@stack.nl>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Harald van Dijk <harald@gigawatt.nl>,
Craig Loomis <cploomis@gmail.com>, dash <dash@vger.kernel.org>
Subject: Re: "command -p" does not correctly limit search to a safe PATH
Date: Sat, 27 Sep 2014 23:57:06 +0200 [thread overview]
Message-ID: <20140927215706.GA25474@stack.nl> (raw)
In-Reply-To: <20140926091942.GB14940@gondor.apana.org.au>
On Fri, Sep 26, 2014 at 05:19:42PM +0800, Herbert Xu wrote:
> On Fri, Jul 19, 2013 at 09:49:31PM +0000, Harald van Dijk wrote:
> >
> > So, how about this, to be applied on top of my previous patch? It
> > defaults to using confstr() if available and reporting a hard error at
> > run time if that fails, but it can be configured to not use confstr(),
> > and/or fall back to a path specified at configuration time:
> Thanks for the patch. But until someone who needs this complexity
> steps up, I'm going to stick with the simpler version below:
> [snip]
> diff --git a/src/var.h b/src/var.h
> index 79ee71a..872e2db 100644
> --- a/src/var.h
> +++ b/src/var.h
> @@ -107,7 +107,7 @@ extern const char defifsvar[];
> extern const char defifs[];
> #endif
> extern const char defpathvar[];
> -#define defpath (defpathvar + 5)
> +#define defpath (defpathvar + 36)
>
> extern int lineno;
> extern char linenovar[];
This needs a comment at the definition of defpathvar in var.c;
otherwise, someone changing the default path will subtly break command
-p without knowing. The number 36 is rather magic too, but it can be
found back through git history.
Alternatively, you could rely on the linker combining common string
constant endings: put in some #define for
"/usr/sbin:/usr/bin:/sbin:/bin" and make defpathvar a #define instead of
a const array.
--
Jilles Tjoelker
next prev parent reply other threads:[~2014-09-27 22:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-10 18:18 "command -p" does not correctly limit search to a safe PATH Craig Loomis
2013-07-14 19:54 ` Harald van Dijk
2013-07-19 21:49 ` Harald van Dijk
2014-09-26 9:19 ` Herbert Xu
2014-09-27 21:57 ` Jilles Tjoelker [this message]
2014-09-26 8:44 ` Herbert Xu
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