Cache can store invalid images

[Brian Elliott]

On a GET request, the image streamed back to the client will be stored in the cache without any re-validation of the checksum. This makes it possible to cache invalid images if the storage backend is malfunctioning.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/10223

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/10223
Committed: http://github.com/openstack/glance/commit/19334f0f8d0d2e8bcc086ef27e44c0a6a80bd9d6
Submitter: Jenkins
Branch: master

commit 19334f0f8d0d2e8bcc086ef27e44c0a6a80bd9d6
Author: Brian Elliott <email address hidden>
Date: Sun Jul 22 14:39:08 2012 -0500

    Do not cache images that fail checksum verfication

    On an image GET, recalculate the image checksum as the image
    data is streamed to the client. Verify that the checksum matches
    the original checksum calculated when the image was added to Glance.
    If checksum validation fails, purge the image from the cache.

    This type of situation could occur if the backend image store
    is malfunctioning.

    bug 1028496

    Change-Id: I9f38bac8360016bb12b5edaad87c50939a538cc0