From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Ulrich Mueller <ulm@gentoo.org>
Cc: Chong Yidong <cyd@stupidchicken.com>, emacs-devel@gnu.org
Subject: Re: "Local variables" denial-of-service attack
Date: Fri, 09 Jan 2009 12:07:48 -0500 [thread overview]
Message-ID: <jwvvdsoifbp.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <18791.27439.738299.220433@a1i15.kph.uni-mainz.de> (Ulrich Mueller's message of "Fri, 9 Jan 2009 16:20:15 +0100")
> Local Variab*les:
> byte-compile-warnings: #1=("circular" "object" . #1#)
> End:
> Visiting such a file will result in Emacs hanging and consuming all
> CPU time. (Normally, aborting with C-g is possible. However, if the
> file is opened with emacsclient there seems to be no way to recover.)
Hmm... that's not good. It's not the end of the world since it's "only"
a DoS, but we should try and fix it. I see two ways:
1 - don't allow (in file-local vars and .dir-local.el) the # escapes
that permit creation of those circular objects.
2 - be more careful about circularities in the
safe-local-variable predicates.
Nb 1 is easier and will solve it "for all cases", so it's probably
a better choice. Of course, it also "denies service" to those rare
individuals who used circular data in file-local variables for
non-DoS purposes. I don't know if there are any on this planet, tho.
Stefan
next parent reply other threads:[~2009-01-09 17:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <18791.27439.738299.220433@a1i15.kph.uni-mainz.de>
2009-01-09 17:07 ` Stefan Monnier [this message]
2009-01-23 8:54 ` "Local variables" denial-of-service attack Ulrich Mueller
2009-02-02 3:14 ` Stefan Monnier
2009-04-02 8:15 ` Ulrich Mueller
2009-04-23 17:49 ` Ulrich Mueller
2009-04-28 2:02 ` Chong Yidong
2009-04-29 3:15 ` Chong Yidong
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