constellation/internal/api/attestationconfigapi/fetcher.go
2023-09-25 11:53:02 +02:00

101 lines
3.8 KiB
Go

/*
Copyright (c) Edgeless Systems GmbH
SPDX-License-Identifier: AGPL-3.0-only
*/
package attestationconfigapi
import (
"context"
"errors"
"fmt"
apifetcher "github.com/edgelesssys/constellation/v2/internal/api/fetcher"
"github.com/edgelesssys/constellation/v2/internal/constants"
"github.com/edgelesssys/constellation/v2/internal/sigstore"
)
const cosignPublicKey = constants.CosignPublicKeyReleases
// ErrNoVersionsFound is returned if no versions are found.
var ErrNoVersionsFound = errors.New("no versions found")
// Fetcher fetches config API resources without authentication.
type Fetcher interface {
FetchAzureSEVSNPVersion(ctx context.Context, azureVersion AzureSEVSNPVersionAPI) (AzureSEVSNPVersionAPI, error)
FetchAzureSEVSNPVersionList(ctx context.Context, attestation AzureSEVSNPVersionList) (AzureSEVSNPVersionList, error)
FetchAzureSEVSNPVersionLatest(ctx context.Context) (AzureSEVSNPVersionAPI, error)
}
// fetcher fetches AttestationCfg API resources without authentication.
type fetcher struct {
apifetcher.HTTPClient
cdnURL string
verifier sigstore.Verifier
}
// NewFetcher returns a new apifetcher.
func NewFetcher() Fetcher {
return NewFetcherWithClient(apifetcher.NewHTTPClient(), constants.CDNRepositoryURL)
}
// NewFetcherWithCustomCDNAndCosignKey returns a new fetcher with custom CDN URL.
func NewFetcherWithCustomCDNAndCosignKey(cdnURL, cosignKey string) Fetcher {
verifier, err := sigstore.NewCosignVerifier([]byte(cosignKey))
if err != nil {
// This relies on an embedded public key. If this key can not be validated, there is no way to recover from this.
panic(fmt.Errorf("creating cosign verifier: %w", err))
}
return newFetcherWithClientAndVerifier(apifetcher.NewHTTPClient(), verifier, cdnURL)
}
// NewFetcherWithClient returns a new fetcher with custom http client.
func NewFetcherWithClient(client apifetcher.HTTPClient, cdnURL string) Fetcher {
verifier, err := sigstore.NewCosignVerifier([]byte(cosignPublicKey))
if err != nil {
// This relies on an embedded public key. If this key can not be validated, there is no way to recover from this.
panic(fmt.Errorf("creating cosign verifier: %w", err))
}
return newFetcherWithClientAndVerifier(client, verifier, cdnURL)
}
func newFetcherWithClientAndVerifier(client apifetcher.HTTPClient, cosignVerifier sigstore.Verifier, url string) Fetcher {
return &fetcher{HTTPClient: client, verifier: cosignVerifier, cdnURL: url}
}
// FetchAzureSEVSNPVersionList fetches the version list information from the config API.
func (f *fetcher) FetchAzureSEVSNPVersionList(ctx context.Context, attestation AzureSEVSNPVersionList) (AzureSEVSNPVersionList, error) {
// TODO(derpsteb): Replace with FetchAndVerify once we move to v2 of the config API.
return apifetcher.Fetch(ctx, f.HTTPClient, f.cdnURL, attestation)
}
// FetchAzureSEVSNPVersion fetches the version information from the config API.
func (f *fetcher) FetchAzureSEVSNPVersion(ctx context.Context, azureVersion AzureSEVSNPVersionAPI) (AzureSEVSNPVersionAPI, error) {
fetchedVersion, err := apifetcher.FetchAndVerify(ctx, f.HTTPClient, f.cdnURL, azureVersion, f.verifier)
if err != nil {
return fetchedVersion, fmt.Errorf("fetching version %s: %w", azureVersion.Version, err)
}
return fetchedVersion, nil
}
// FetchAzureSEVSNPVersionLatest returns the latest versions of the given type.
func (f *fetcher) FetchAzureSEVSNPVersionLatest(ctx context.Context) (res AzureSEVSNPVersionAPI, err error) {
var list AzureSEVSNPVersionList
list, err = f.FetchAzureSEVSNPVersionList(ctx, list)
if err != nil {
return res, ErrNoVersionsFound
}
if len(list) < 1 {
return res, ErrNoVersionsFound
}
getVersionRequest := AzureSEVSNPVersionAPI{
Version: list[0], // latest version is first in list
}
res, err = f.FetchAzureSEVSNPVersion(ctx, getVersionRequest)
if err != nil {
return res, err
}
return
}