mailing list of musl libc
 help / color / mirror / code / Atom feed
From: "Sören Tempel" <soeren@soeren-tempel.net>
To: musl@lists.openwall.com
Subject: Re: [musl] tzset() cannot handle arbitrary inputs
Date: Sun, 05 Sep 2021 23:26:08 +0200	[thread overview]
Message-ID: <38ZW90QHEA9XD.3GB2I1P1ZLKDB@8pit.net> (raw)
In-Reply-To: <20210905173949.GE3090@voyager>

Markus Wichmann <nullplan@gmx.net> wrote:
> Hi all,

Hi,

> The user setting TZ is also the one getting the crashes. The
> assumption is less that the input is always valid, but more that if it
> is invalid, the user will only be hacking themselves.

This is only true under the assumption that $TZ itself is never set to a
value derived from an untrusted source. See the aforementioned calcurse
code for example where this assumption does not hold. If you search
GitHub or use codesearch.debian.net you will find plenty additional
examples where people "abuse" $TZ to query information about zonefiles
by name. Please also note that these spatial memory safety violations
are UB and thus might or might not lead to a crash.

Greetings,
Sören

  reply	other threads:[~2021-09-05 21:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-05 13:36 Sören Tempel
2021-09-05 17:39 ` Markus Wichmann
2021-09-05 21:26   ` Sören Tempel [this message]
2021-09-05 23:11     ` Rich Felker

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=38ZW90QHEA9XD.3GB2I1P1ZLKDB@8pit.net \
    --to=soeren@soeren-tempel.net \
    --cc=musl@lists.openwall.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. 
Code repositories for project(s) associated with this public inbox

	https://git.vuxu.org/mirror/musl/

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 NNTP newsgroup(s).