From: "João Távora" <joaotavora@gmail.com>
To: Stefan Monnier <monnier@IRO.UMontreal.CA>
Cc: emacs-devel@gnu.org
Subject: Re: [Emacs-diffs] scratch/allow-custom-load-paths-in-elisp-flymake 4ef9711: Allow custom load paths in elisp's byte-compilation Flymake
Date: Wed, 05 Dec 2018 15:14:04 +0000 [thread overview]
Message-ID: <jjb7egoypj7.fsf@gmail.com> (raw)
In-Reply-To: <jwvzhtkfvgg.fsf-monnier+emacsdiffs@gnu.org> (Stefan Monnier's message of "Tue, 04 Dec 2018 23:34:48 -0500")
Stefan Monnier <monnier@IRO.UMontreal.CA> writes:
>> +(put 'elisp-flymake-byte-compile-load-path 'safe-local-variable
>> + (lambda (x) (and (listp x) (catch 'tag
>> + (dolist (path x t) (unless (stringp path)
>> + (throw 'tag nil)))))))
>
> Just reminded me: we have a serious problem w.r.t security of
> flymake-mode in Elisp buffers: if someone enables flymake-mode for all
> elisp-mode buffers (i.e. what I'd like to do by default), the mere act
> of visiting an Elisp file means that file will be passed to byte-compile
> which will happily execute some of the code within, running arbitrarily
> dangerous code.
True. And that's why we don't enable flymake-mode automatically, and
possibly never will (unless we come up with a solution). The fact that
it is so inherently dangerous is the reason that I considered adding a
safety spec to elisp-flymake-byte-compile-load-path at all, because
having flymake-mode in elisp is already quite dangerous it itself.
But it does make it slightly *more* dangerous, because you can visit a
file that would otherwise be safe, but be betrayed by a .dir-locals.el
that spoofs the load-path to run some attacker's code. Not sure if this
is a reasonable scenario.
So should I push this to master with or without the safety spec?
João
next prev parent reply other threads:[~2018-12-05 15:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20181204233600.7907.75252@vcs0.savannah.gnu.org>
[not found] ` <20181204233601.273DD209DC@vcs0.savannah.gnu.org>
2018-12-05 4:34 ` [Emacs-diffs] scratch/allow-custom-load-paths-in-elisp-flymake 4ef9711: Allow custom load paths in elisp's byte-compilation Flymake Stefan Monnier
2018-12-05 15:14 ` João Távora [this message]
2018-12-05 20:00 ` Glenn Morris
2018-12-05 20:40 ` João Távora
2018-12-08 13:23 ` Safety of elisp-flymake-byte-compile (Was Re: [Emacs-diffs] scratch/allow-custom-load-paths) João Távora
2018-12-08 15:36 ` Stefan Monnier
2018-12-10 0:20 ` João Távora
2018-12-10 2:22 ` Stefan Monnier
2018-12-10 23:17 ` João Távora
2018-12-11 14:03 ` Stefan Monnier
2018-12-14 12:00 ` João Távora
2018-12-14 12:15 ` Stefan Monnier
2018-12-14 13:09 ` João Távora
2018-12-14 13:27 ` Stefan Monnier
2018-12-14 13:38 ` João Távora
2018-12-14 14:13 ` Stefan Monnier
2018-12-11 19:30 ` Sandboxing (was: Safety of elisp-flymake-byte-compile) Stefan Monnier
2018-12-14 1:35 ` Sandboxing João Távora
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=jjb7egoypj7.fsf@gmail.com \
--to=joaotavora@gmail.com \
--cc=emacs-devel@gnu.org \
--cc=monnier@IRO.UMontreal.CA \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).