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[Bug 1449062] Re: qemu-img calls need to be restricted by ulimit (CVE-2015-5162)

To: yahoo-eng-team@xxxxxxxxxxxxxxxxxxx
From: Mathew Hodson <mathew.hodson@xxxxxxxxx>
Date: Mon, 08 Aug 2016 04:21:29 -0000
Reply-to: Bug 1449062 <1449062@xxxxxxxxxxxxxxxxxx>
Sender: bounces@xxxxxxxxxxxxx

** Project changed: cinder => ubuntu-translations

** No longer affects: ubuntu-translations

** Project changed: glance => ubuntu-translations

** Changed in: ubuntu-translations
    Milestone: ongoing => None

** No longer affects: ubuntu-translations

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https://bugs.launchpad.net/bugs/1449062

Title:
  qemu-img calls need to be restricted by ulimit (CVE-2015-5162)

Status in OpenStack Compute (nova):
  Fix Released
Status in OpenStack Security Advisory:
  Confirmed
Status in python-oslo.concurrency package in Ubuntu:
  Fix Released
Status in python-oslo.concurrency source package in Wily:
  Fix Committed
Status in python-oslo.concurrency source package in Xenial:
  Fix Released
Status in python-oslo.concurrency source package in Yakkety:
  Fix Released

Bug description:
  Reported via private E-mail from Richard W.M. Jones.

  Turns out qemu image parser is not hardened against malicious input
  and can be abused to allocated an arbitrary amount of memory and/or
  dump a lot of information when used with "--output=json".

  The solution seems to be: limit qemu-img ressource using ulimit.

  Example of abuse:

  -- afl1.img --

  $ /usr/bin/time qemu-img info afl1.img
  image: afl1.img
  [...]
  0.13user 0.19system 0:00.36elapsed 92%CPU (0avgtext+0avgdata 642416maxresident)k
  0inputs+0outputs (0major+156927minor)pagefaults 0swaps

  The original image is 516 bytes, but it causes qemu-img to allocate
  640 MB.

  -- afl2.img --

  $ qemu-img info --output=json afl2.img | wc -l
  589843

  This is a 200K image which causes qemu-img info to output half a
  million lines of JSON (14 MB of JSON).

  Glance runs the --output=json variant of the command.

  -- afl3.img --

  $ /usr/bin/time qemu-img info afl3.img
  image: afl3.img
  [...]
  0.09user 0.35system 0:00.47elapsed 94%CPU (0avgtext+0avgdata 1262388maxresident)k
  0inputs+0outputs (0major+311994minor)pagefaults 0swaps

  qemu-img allocates 1.3 GB (actually, a bit more if you play with
  ulimit -v).  It appears that you could change it to allocate
  arbitrarily large amounts of RAM.

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