From: Erik van Konijnenburg <ekonijn@xs4all.nl>
To: Dave Jones <davej@redhat.com>
Cc: Paul Jackson <pj@sgi.com>, Petr Baudis <pasky@ucw.cz>,
git@vger.kernel.org, mj@ucw.cz
Subject: Re: fix mktemp (remove mktemp ;)
Date: Sun, 17 Apr 2005 02:51:08 +0200 [thread overview]
Message-ID: <20050417025108.G2442@banaan.localdomain> (raw)
In-Reply-To: <20050417003325.GA15608@redhat.com>; from davej@redhat.com on Sat, Apr 16, 2005 at 08:33:25PM -0400
On Sat, Apr 16, 2005 at 08:33:25PM -0400, Dave Jones wrote:
> On Sat, Apr 16, 2005 at 05:02:21PM -0700, Paul Jackson wrote:
> > > And racy. And not guaranteed to come up with fresh new files.
> >
> > In theory perhaps. In practice no.
> >
> > Even mktemp(1) can collide, in theory, since there is no practical way
> > in shell scripts to hold open and locked the file from the instant of it
> > is determined to be a unique name.
>
> Using the pid as a 'random' number is a bad idea. all an attacker
> has to do is create 65535 symlinks in /usr/tmp, and he can now
> overwrite any file you own.
>
> mktemp is being used here to provide randomness in the filename,
> not just a uniqueness.
How about putting using .git/tmp.$$ or similar as tempfile?
This should satisfy both the portability and security requirements,
since the warnings against using $$ only apply to public directories.
Regards,
Erik
next prev parent reply other threads:[~2005-04-17 0:47 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-16 23:27 [PATCH] fix mktemp (remove mktemp ;) Paul Jackson
2005-04-16 23:27 ` [PATCH] missing mkdir -p flag in gitdiff-do Paul Jackson
2005-04-16 23:28 ` [PATCH] optimize gitdiff-do script Paul Jackson
2005-04-16 23:43 ` Petr Baudis
2005-04-17 0:10 ` Paul Jackson
2005-04-18 15:23 ` Paul Jackson
2005-04-18 18:30 ` Petr Baudis
2005-04-18 19:17 ` Paul Jackson
2005-05-10 2:56 ` Paul Jackson
2005-04-16 23:36 ` [PATCH] fix mktemp (remove mktemp ;) Jan-Benedict Glaw
2005-04-16 23:46 ` Paul Jackson
2005-04-16 23:37 ` Petr Baudis
2005-04-17 0:02 ` Paul Jackson
2005-04-17 0:33 ` Dave Jones
2005-04-17 0:44 ` Paul Jackson
2005-04-17 0:57 ` Dave Jones
2005-04-17 1:03 ` David Lang
2005-04-17 1:15 ` Paul Jackson
2005-04-17 2:38 ` Brian O'Mahoney
2005-04-17 2:46 ` Paul Jackson
2005-04-17 0:51 ` Erik van Konijnenburg [this message]
2005-04-17 1:18 ` Paul Jackson
2005-04-18 3:01 ` Herbert Xu
2005-04-18 4:47 ` Paul Jackson
2005-04-18 12:12 ` Florian Weimer
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