Initial attestations support #2935

jedevc · 2022-06-27T14:52:17Z

This PR introduces support for in-toto attestations, as specified in part 1 of #2773 (comment).

This is dependent on #2929, and includes a commit from there to better handle garbage collection of attestation refs.

In it's current state, this is a first-pass - and some things are expected to change before merge:

Media types for exported content
- Additionally, these need to be added to the image pusher code to prevent encountered unknown type ... children may not be fetched messages.
OS/Platform values for attestations - currently selected none/none
Exact Gateway API protobuf format
Attestation struct format
Hopefully a few more tests

exporter/containerimage/writer.go

errordeveloper

Great work! Just a few initial thoughts... :)

exporter/containerimage/writer.go

jedevc · 2022-06-27T15:42:33Z

Not quite sure how this model would interact with tooling that generates a lot of attestations. One possible way might be to allow grouping attestations together into layers, though I'm not quite sure the mechanics of the API that would use.

jedevc · 2022-07-07T14:33:34Z

Another complexity that's come up that we might want to investigate - we might want to have the capacity to have scanners able to analyze individual layers - so for that we might want to expose the ability to create attestations about single layers. Exactly how a scanner might create these attestations feels like something that's up to each scanner, and the interface that gets defined for that, but the storage format is something to maybe work out sooner. We could potentially allow attaching attestations to arbitrary Refs and then translate them to layer digests as part of the exporter?

errordeveloper · 2022-07-11T12:40:22Z

Another complexity that's come up that we might want to investigate - we might want to have the capacity to have scanners able to analyze individual layers - so for that we might want to expose the ability to create attestations about single layers. Exactly how a scanner might create these attestations feels like something that's up to each scanner, and the interface that gets defined for that, but the storage format is something to maybe work out sooner. We could potentially allow attaching attestations to arbitrary Refs and then translate them to layer digests as part of the exporter?

One use-case would be to produce attestations about what buildkit itself does, i.e. for a RUN statement you would want to have a trace of what binaries were exec'ed, what files openend etc. You would probably want to included checksum of each file as well as stdout and stderr. For COPY/ADD you do want file chechsums too as well as list of any files that had been overwritten. These use-cases would probably translate to buildkit features, perhaps these could helpeful in shaping some aspects of the implementation.

jedevc · 2022-07-18T17:37:20Z

Based on discussions, a couple notes:

Buildkit will have to have some knowledge of attestations somewhere - we can't entirely treat them like a completely opaque blob. It might still be worth distinguishing between the concept of a "generic buildkit attestation" which is then translated to an in-toto attestation at export, like the current code does?
Layer-based attestations are probably not going to be a thing, since they may not be particularly useful, since they don't necessarily map explicitly to the frontend's input (like a dockerfile). How files in an image map to an instruction, or the layer-based structure of an image is expressed in SBOMs is likely an issue to be solved at the frontend level, and expressed within the structure of the attestation if necessary.
Attestation bundling is already sort of supported atm, by splitting out each platform's attestations into a separate manifest. In the future, we could allow splitting out attestations further into multiple attestation manifests per platform if necessary if we want to split out bundles even more - but we can likely address this later as we see how the unbundled stuff scales.

tonistiigi

One thing I might have forgotten in some descriptions is that attestations shouldn't be only for image-based exporter. They should also work with local/tar exporter by creating additional files. So currently some code being under containerimage pkg might not be fully correct.

To create the additional files there needs to be some logic for naming them. It is similar to the predicate type, but maybe not exactly the same value? Also I think in these cases it may be more common that in-toto wrapping is optional. Eg. lets say I export local binary with provenance and SBOM attestation that both are exported as a separate file. Provenance is only defined via in-toto so doesn't make much sense to split it out but for SBOM I might expect to have a file with just the SBOM data. Maybe it is fine if all our defaults are in in-toto wrapping for now.

If it complicates things we can pick this part up in a follow up but a thing to consider when choosing the code location and proto types.

frontend/gateway/pb/gateway.proto

frontend/gateway/forwarder/forward.go

frontend/result.go

exporter/containerimage/attestations.go

exporter/containerimage/writer.go

client/client_test.go

frontend/gateway/pb/gateway.proto

frontend/gateway/gateway.go

exporter/containerimage/attestations.go

jedevc · 2022-07-20T15:19:56Z

exporter/containerimage/exptypes/attestations.go

+package exptypes
+
+const (
+	MediaTypeDockerSchema2AttestationType = "application/vnd.in-toto+json"


Might want to sync with the containerd people on what to call this - since we'll need to get this to be recognized, or we'll see the the "reference for unknown type: application/vnd.in-toto+json" warning from https://github.com/jedevc/buildkit/blob/wip-attestations-sbom/vendor/github.com/containerd/containerd/remotes/handlers.go#L83

In the meantime, not quite sure where these media type definitions belong...

exporter/containerimage/exptypes/attestations.go

util/attestation/attestations.go

exporter/containerimage/writer.go

jedevc · 2022-07-26T10:24:08Z

I'm happy with the state of this now 😄 A couple of follow-ups will likely be necessary: adding support for other exporters (e.g. tar/local), clean-up of conversions between different Result types (which makes the attestation plumbing ugly), and probably other things as we add SBOMs.

jedevc · 2022-08-04T17:50:09Z

As discussed with @tonistiigi, to keep the scope of this PR low, a list of the planned follow-ups:

Suppress warning messages from containerd pusher
- attestations: suppress containerd media type warnings #3063
Export attestations with local/tar exporters
- Export attestations for other exporters #3184
Tidy up the Result types (so we need less messy conversion code)
- Proposal: generic *.Result types #3036
- Proposal: attestations ref map merge #3038
Set oci-mediatypes when using attestations and annotations, instead of producing not-completely-in-spec manifests and manifest lists
- Force oci-mediatypes for containerimage outputs that utilize annotations #3061

tonistiigi · 2022-08-10T05:06:08Z

frontend/gateway/pb/gateway.proto

+	message Subject {
+		message SelfSubject {
+		}
+		message RawSubject {


I'm not sure if allowing RawSubject isn't a security concern actually. If we let the frontend to claim that attestation is for a random digest there is no way BuildKit can validate this is any way.

It is possible we should only allow attesting data when we can prove how it was built. Or at least we should make it so that it is clear that this subject is not allowed to point to any container objects so validators know that this is not to be trusted.

Something to pick up again on follow-ups.

I think it depends on the security model that users are running buildkit under - but agreed.

We can revisit this, I think we could work round the need for a RawSubject by allowing attesting to individual files (composed of a Ref + Path), with something like a FileSubject which is the main other use I can see.

tonistiigi · 2022-08-10T05:10:47Z

frontend/gateway/pb/gateway.proto

+message InToto {
+	string predicateType = 1;
+	Ref predicateRef = 2;
+	string predicatePath = 3;


Follow-up: as discussed for SBOMs we should have a way that this path can point to a list of attestations. So SBOM generator can generate multiple SBOMs with a single invocation that are listed in a file and BuildKit will create an independent attestation record for each file.

frontend/gateway/client/result.go

exporter/containerimage/writer.go

client/client_test.go

solver/pb/caps.go

Introduce attestations message structures to protobuf. Each result can contain multiple attestations, keyed by the platform they apply to. Each attestation has a predicate type, a ref+path to the predicate content, and a selection of subjects, which can either be freeform name + digest fields, or the resulting image manifest for the target. Signed-off-by: Justin Chadwell <me@jedevc.com>

This patch connects the raw protobuf attestations through to the gateway clients and servers, ensuring that the results are properly passed through correctly, and that the appropriate refs are correctly cleaned up. Signed-off-by: Justin Chadwell <me@jedevc.com>

Connect the attestations output from the frontend outputs into the exporters, allowing the containerimage-based exporters to correctly create in-toto attestations according to OCI reference-types Proposal F. Attestations are grouped per-platform, and placed into manifests that reference their targets - each layer in these manifests contain a custom in-toto media type with the raw attestation content. Signed-off-by: Justin Chadwell <me@jedevc.com>

Signed-off-by: Justin Chadwell <me@jedevc.com>

The image info registry helpers provide utilities for reading content from providers such as registries which can be easily used to inspect image content. This is an alternative to requiring the containerd puller, or exporting as an oci tarball. By moving the helpers into testutil, we allow other testing components to utilize the helpers, instead of just the dockerfile tests. Signed-off-by: Justin Chadwell <me@jedevc.com>

Signed-off-by: Justin Chadwell <me@jedevc.com>

This will eventually clients to query the server to confirm if attestations are supported. However, for now, we can keep it disabled until the gateway api stabilizes. Signed-off-by: Justin Chadwell <me@jedevc.com>

jedevc requested review from tonistiigi and crazy-max June 27, 2022 14:52

jedevc marked this pull request as draft June 27, 2022 15:06

errordeveloper reviewed Jun 27, 2022

View reviewed changes

exporter/containerimage/writer.go Outdated Show resolved Hide resolved

jedevc force-pushed the attestations branch 2 times, most recently from d11f29d to 2c364d7 Compare June 27, 2022 15:20

errordeveloper reviewed Jun 27, 2022

View reviewed changes

exporter/containerimage/writer.go Outdated Show resolved Hide resolved

exporter/containerimage/writer.go Outdated Show resolved Hide resolved

exporter/containerimage/writer.go Show resolved Hide resolved

jedevc marked this pull request as ready for review July 18, 2022 16:46

jedevc force-pushed the attestations branch from 2c364d7 to f1da4fb Compare July 19, 2022 11:12

tonistiigi reviewed Jul 19, 2022

View reviewed changes

errordeveloper reviewed Jul 20, 2022

View reviewed changes

frontend/gateway/pb/gateway.proto Outdated Show resolved Hide resolved

errordeveloper reviewed Jul 20, 2022

View reviewed changes

frontend/gateway/pb/gateway.proto Show resolved Hide resolved

errordeveloper reviewed Jul 20, 2022

View reviewed changes

frontend/gateway/gateway.go Outdated Show resolved Hide resolved

errordeveloper reviewed Jul 20, 2022

View reviewed changes

frontend/gateway/gateway.go Outdated Show resolved Hide resolved

errordeveloper reviewed Jul 20, 2022

View reviewed changes

exporter/containerimage/attestations.go Outdated Show resolved Hide resolved

jedevc commented Jul 20, 2022

View reviewed changes

jedevc force-pushed the attestations branch 2 times, most recently from 2471252 to c651b95 Compare July 20, 2022 15:57

jedevc commented Jul 21, 2022

View reviewed changes

util/attestation/attestations.go Outdated Show resolved Hide resolved

tonistiigi reviewed Jul 26, 2022

View reviewed changes

exporter/containerimage/writer.go Outdated Show resolved Hide resolved

exporter/containerimage/writer.go Outdated Show resolved Hide resolved

jedevc force-pushed the attestations branch from 51f6502 to 705f1fe Compare July 26, 2022 10:21

jedevc requested a review from tonistiigi July 26, 2022 10:24

jedevc force-pushed the attestations branch from 705f1fe to 897c3e6 Compare July 26, 2022 10:51

jedevc mentioned this pull request Jul 26, 2022

SBOM attestations generation #2983

Merged

3 tasks

jedevc force-pushed the attestations branch from 897c3e6 to 27e04f6 Compare August 3, 2022 09:01

tonistiigi reviewed Aug 10, 2022

View reviewed changes

jedevc force-pushed the attestations branch from 27e04f6 to 624f9ea Compare August 10, 2022 16:28

tonistiigi mentioned this pull request Aug 10, 2022

Generate SLSA provenance for binaries in GitHub releases docker/buildx#1243

Open

jedevc force-pushed the attestations branch from 624f9ea to 4e0eb12 Compare August 11, 2022 13:18

jedevc added 7 commits August 11, 2022 14:25

util: silence push warnings for attestation media types

01369e1

Signed-off-by: Justin Chadwell <me@jedevc.com>

client: add integration tests for attestations

843f4ee

Signed-off-by: Justin Chadwell <me@jedevc.com>

solver: add attestations capability

d76e401

This will eventually clients to query the server to confirm if attestations are supported. However, for now, we can keep it disabled until the gateway api stabilizes. Signed-off-by: Justin Chadwell <me@jedevc.com>

jedevc force-pushed the attestations branch from 4e0eb12 to d76e401 Compare August 11, 2022 13:27

This was referenced Aug 16, 2022

Proposal: generic *.Result types #3036

Merged

Proposal: attestations ref map merge #3038

Merged

tonistiigi approved these changes Aug 23, 2022

View reviewed changes

tonistiigi merged commit 9c34fc5 into moby:master Aug 23, 2022

This was referenced Aug 24, 2022

Force oci-mediatypes for containerimage outputs that utilize annotations #3061

Merged

attestations: suppress containerd media type warnings #3063

Merged

Subject names for attestations #3070

Merged

Attestations refactoring #3073

Merged

jedevc mentioned this pull request Oct 17, 2022

Export attestations for other exporters #3184

Closed

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Initial attestations support #2935

Initial attestations support #2935

jedevc commented Jun 27, 2022 •

edited

errordeveloper left a comment

jedevc commented Jun 27, 2022

jedevc commented Jul 7, 2022

errordeveloper commented Jul 11, 2022 •

edited

jedevc commented Jul 18, 2022

tonistiigi left a comment

jedevc Jul 20, 2022

jedevc commented Jul 26, 2022

jedevc commented Aug 4, 2022 •

edited

tonistiigi Aug 10, 2022

jedevc Aug 10, 2022 •

edited

tonistiigi Aug 10, 2022

Initial attestations support #2935

Initial attestations support #2935

Conversation

jedevc commented Jun 27, 2022 • edited

errordeveloper left a comment

Choose a reason for hiding this comment

jedevc commented Jun 27, 2022

jedevc commented Jul 7, 2022

errordeveloper commented Jul 11, 2022 • edited

jedevc commented Jul 18, 2022

tonistiigi left a comment

Choose a reason for hiding this comment

jedevc Jul 20, 2022

Choose a reason for hiding this comment

jedevc commented Jul 26, 2022

jedevc commented Aug 4, 2022 • edited

tonistiigi Aug 10, 2022

Choose a reason for hiding this comment

jedevc Aug 10, 2022 • edited

Choose a reason for hiding this comment

tonistiigi Aug 10, 2022

Choose a reason for hiding this comment

jedevc commented Jun 27, 2022 •

edited

errordeveloper commented Jul 11, 2022 •

edited

jedevc commented Aug 4, 2022 •

edited

jedevc Aug 10, 2022 •

edited