tree 2007216396f8189b051a9ce4cb78427d6682582c
parent cab12b78ff7bfbfbb8a42f309fd51eb9dc293b60
author Nandhini Rengaraj <nrengaraj@google.com> 1738284278 +0000
committer Nandhini Rengaraj <nrengaraj@google.com> 1738610898 -0800

provisioner, preloader: Add integrity checks for build context

Compute SHA-256 checksums for all the entities we upload to GCS that are
to be used in the preloaded VM (ie. the build context). The computed
checksums are set as VM instance metadata of format <file_name> : <hash>
using daisy when the instance is spun up. In the preload VM, download
the build context and verify the integrity by comparing the checksum
from instance metadata with the downloaded file. Proceed if there are
no errors, exit otherwise.

BUG=b/214451194
TEST=build cos-customizer docker image and ran derived image builds, cos-customizer integration tests
RELEASE_NOTE=None

Change-Id: I1c4feeca83ab8e7340f25370c3574de7cde407e9
Reviewed-on: https://cos-review.googlesource.com/c/cos/tools/+/91805
Tested-by: Nandhini Rengaraj <nrengaraj@google.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Cloud-Build: GCB Service account <228075978874@cloudbuild.gserviceaccount.com>