From: Eric Blake <eblake@redhat.com>
To: The Cygwin Mailing List <cygwin@cygwin.com>
Subject: Re: Updated: bash-4.1.16-8
Date: Fri, 03 Oct 2014 04:24:00 -0000 [thread overview]
Message-ID: <542E24F9.4070409@redhat.com> (raw)
In-Reply-To: <542E1B8C.7070807@byu.net>
[-- Attachment #1: Type: text/plain, Size: 972 bytes --]
On 10/02/2014 09:44 PM, Eric Blake (cygwin) wrote:
> To avoid confusion, the following test unambiguously tests if you are
> vulnerable to ShellShock:
> $ env 'x=() { echo vulnerable; }' bash -c x
>
> If it prints "x: command not found", your version of bash is safe and
> not subject to remote exploits. If it prints "vulnerable", you need to
> upgrade now.
D'oh - it was pointed out to me that on systems where the X server is
installed, the command 'x' might actually attempt to fire up an X server
rather than reporting command not found. Don't worry - that's also a
sign that you are NOT vulnerable (the attempt to define a function to
mask out an existing command did not succeed).
But it's better to write a probe that is less likely to conflict with a
real command:
$ env 'nosuch=() { echo vulnerable; }' bash -c nosuch
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 539 bytes --]
parent reply other threads:[~2014-10-03 4:24 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <542E1B8C.7070807@byu.net>]
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
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=542E24F9.4070409@redhat.com \
--to=eblake@redhat.com \
--cc=cygwin@cygwin.com \
/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.
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).