Task #7960: FIPS and support for ALLOWED_CONTENT_CHECKSUMS
Remove checksum filtering in Remote.get_downloader and add checksum type enforcement to downloaders itself
The downloaders don't have any capability to only use those checksums that are in
ALLOWED_CONTENT_CHECKSUMS. This usage happens here.
Remote.get_downloaderwill filter out the checksums on an Artifact to only those that are allowed. That happens here.
DeclarativeArtifact.downloadalso filters checksums. That occurs here.
The First Issue¶
(1) is an issue because the downloaders can be used directly and as-is they won't respect the
Solution to the first Issue¶
The downloader code should be adjusted to only use those checksums in
ALLOWED_CONTENT_CHECKSUMS. If any checksums are specified (trusted or not), at least one trusted hasher must be available or an exception should be raised. If no checksums are requested the downloader should be allowed to proceed because some content does not have checksums, e.g. the very first metadata file fetched, or ruby content.
The second problem¶
By (2)(3) filtering out checksums, it could misrepresent the set of checksums to the downloader as being an empty set when really checksums exist but no trusted checksums exist.
Solution to the second problem¶
Remove the filtering done in
DeclarativeArtiface.download. Instead have it pass all original checksums unmodified to the downloader.