Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Mon, 06 Jul 2015 22:04:04 +0100
From: Simon McVittie <>
Subject: Re: TR : CVE request for dash 0.5.7-3  x86-64 local
 buffer overflow

On 06/07/15 13:58, wrote:
> I discover it using bash who sent me a SIGKILL (no real crash) and
> closed my shell in certain circumstances:
> kmkz@...z:/tmp$  `perl -e '$i=0;while($i<= 500){print"DEAD"x10;}'`
> bash: xrealloc : ../bash/subst.c:5184 : impossible d'allouer 2097152
> octets (4460544 octets allou├ęs)
> So I wanted to try using my /bin/dash and... I had a local crash !

You told dash to interpret a command 2 gigabytes long, and it failed to
do so; additionally, the failure was a crash, not a deterministic
semi-graceful exit. That sounds like a bug.

However, to be a security vulnerability rather than "just a bug", a
buffer overflow is not enough; to be a security vulnerability, it would
have to be an *attacker-triggerable* buffer overflow.

Is there any circumstance under which an attacker - not you - can cause
this to happen, other than via an arbitrary-code-execution vulnerability
in some other component?

(If you are already vulnerable to attacker-controlled arbitrary code
execution, then dash crashing is the least of your worries.)


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.