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feat: generate vsa policy value from file

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This commit is contained in:
mrjoelkamp
2024-08-14 09:16:24 -05:00
parent 8c6df28540
commit d2a8348ae8
14 changed files with 114 additions and 39 deletions
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8
pkg/attest/verify.go
View File

@@ -86,6 +86,12 @@ func toVerificationResult(p *policy.Policy, input *policy.Input, result *policy.
return nil, err
}
vsaPolicy := attestation.VSAPolicy{URI: result.Summary.PolicyURI, Digest: p.Digest}
// if the policy URI is not set by the result summary then use the policy's target URI
if vsaPolicy.URI == "" {
vsaPolicy = attestation.VSAPolicy{URI: p.URI, Digest: p.Digest}
}
return &VerificationResult{
Policy: p,
Outcome: outcome,
@@ -103,7 +109,7 @@ func toVerificationResult(p *policy.Policy, input *policy.Input, result *policy.
},
TimeVerified: time.Now().UTC().Format(time.RFC3339),
ResourceURI: resourceURI,
Policy: attestation.VSAPolicy{URI: result.Summary.PolicyURI},
Policy: vsaPolicy,
VerificationResult: outcomeStr,
VerifiedLevels: result.Summary.SLSALevels,
},

6
pkg/attest/verify_test.go
View File

@@ -112,7 +112,8 @@ func TestVSA(t *testing.T) {
assert.Equal(t, "PASSED", attestationPredicate.VerificationResult)
assert.Equal(t, "docker-official-images", attestationPredicate.Verifier.ID)
assert.Equal(t, []string{"SLSA_BUILD_LEVEL_3"}, attestationPredicate.VerifiedLevels)
assert.Equal(t, "https://docker.com/official/policy/v0.1", attestationPredicate.Policy.URI)
assert.Equal(t, PassPolicyDir+"/policy.rego", attestationPredicate.Policy.URI)
assert.Equal(t, map[string]string{"sha256": "d71d6b8f49fcba1295b16f5394dd5863a14e4277eb663d66d8c48e392509afe0"}, attestationPredicate.Policy.Digest)
}
func TestVerificationFailure(t *testing.T) {
@@ -162,7 +163,8 @@ func TestVerificationFailure(t *testing.T) {
assert.Equal(t, "FAILED", attestationPredicate.VerificationResult)
assert.Equal(t, "docker-official-images", attestationPredicate.Verifier.ID)
assert.Equal(t, []string{"SLSA_BUILD_LEVEL_3"}, attestationPredicate.VerifiedLevels)
assert.Equal(t, "https://docker.com/official/policy/v0.1", attestationPredicate.Policy.URI)
assert.Equal(t, FailPolicyDir+"/policy.rego", attestationPredicate.Policy.URI)
assert.Equal(t, map[string]string{"sha256": "ad045e1bd7cd602d90196acf68f2c57d7b51565d59e6e30e30d94ae86aa16201"}, attestationPredicate.Policy.Digest)
}
func TestSignVerify(t *testing.T) {

3
pkg/attestation/vsa.go
View File

@@ -26,7 +26,8 @@ type VSAVerifier struct {
}
type VSAPolicy struct {
URI string `json:"uri"`
URI string `json:"uri"`
Digest map[string]string `json:"digest"`
}
type VSAInputAttestation struct {

4
pkg/config/config.go
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@@ -36,13 +36,13 @@ func LoadTUFMappings(tufClient tuf.Downloader, localTargetsDir string) (*PolicyM
return nil, fmt.Errorf("tuf client not set")
}
filename := MappingFilename
_, fileContents, err := tufClient.DownloadTarget(filename, filepath.Join(localTargetsDir, filename))
file, err := tufClient.DownloadTarget(filename, filepath.Join(localTargetsDir, filename))
if err != nil {
return nil, fmt.Errorf("failed to download policy mapping file %s: %w", filename, err)
}
mappings := &policyMappingsFile{}
err = yaml.Unmarshal(fileContents, mappings)
err = yaml.Unmarshal(file.Data, mappings)
if err != nil {
return nil, fmt.Errorf("failed to unmarshal policy mapping file %s: %w", filename, err)
}

8
pkg/mirror/targets.go
View File

@@ -23,7 +23,7 @@ func (m *TUFMirror) GetTUFTargetMirrors() ([]*Image, error) {
targets := md.Targets[metadata.TARGETS].Signed.Targets
for _, t := range targets {
// download target file
_, data, err := m.TUFClient.DownloadTarget(t.Path, filepath.Join(m.tufPath, "download"))
file, err := m.TUFClient.DownloadTarget(t.Path, filepath.Join(m.tufPath, "download"))
if err != nil {
return nil, fmt.Errorf("failed to download target %s: %w", t.Path, err)
}
@@ -38,7 +38,7 @@ func (m *TUFMirror) GetTUFTargetMirrors() ([]*Image, error) {
}
name := hash.String() + "." + t.Path
ann := map[string]string{tufFileAnnotation: name}
layer := mutate.Addendum{Layer: static.NewLayer(data, tufTargetMediaType), Annotations: ann}
layer := mutate.Addendum{Layer: static.NewLayer(file.Data, tufTargetMediaType), Annotations: ann}
img, err = mutate.Append(img, layer)
if err != nil {
return nil, fmt.Errorf("failed to append role layer to image: %w", err)
@@ -69,7 +69,7 @@ func (m *TUFMirror) GetDelegatedTargetMirrors() ([]*Index, error) {
// for each target file, create an image with the target file as a layer
for _, target := range roleMeta.Signed.Targets {
// download target file
_, data, err := m.TUFClient.DownloadTarget(target.Path, filepath.Join(m.tufPath, "download"))
file, err := m.TUFClient.DownloadTarget(target.Path, filepath.Join(m.tufPath, "download"))
if err != nil {
return nil, fmt.Errorf("failed to download target %s: %w", target.Path, err)
}
@@ -89,7 +89,7 @@ func (m *TUFMirror) GetDelegatedTargetMirrors() ([]*Index, error) {
}
name := hash.String() + "." + filename
ann := map[string]string{tufFileAnnotation: name}
layer := mutate.Addendum{Layer: static.NewLayer(data, tufTargetMediaType), Annotations: ann}
layer := mutate.Addendum{Layer: static.NewLayer(file.Data, tufTargetMediaType), Annotations: ann}
img, err = mutate.Append(img, layer)
if err != nil {
return nil, fmt.Errorf("failed to append role layer to image: %w", err)

31
pkg/policy/policy.go
View File

@@ -8,6 +8,7 @@ import (
"path/filepath"
"github.com/distribution/reference"
"github.com/docker/attest/internal/util"
"github.com/docker/attest/pkg/attestation"
"github.com/docker/attest/pkg/config"
"github.com/docker/attest/pkg/oci"
@@ -17,6 +18,8 @@ func resolveLocalPolicy(opts *Options, mapping *config.PolicyMapping, imageName
if opts.LocalPolicyDir == "" {
return nil, fmt.Errorf("local policy dir not set")
}
var URI string
var digest map[string]string
files := make([]*File, 0, len(mapping.Files))
for _, f := range mapping.Files {
filename := f.Path
@@ -29,10 +32,21 @@ func resolveLocalPolicy(opts *Options, mapping *config.PolicyMapping, imageName
Path: filename,
Content: fileContents,
})
// if the file is a policy file, store the URI and digest
if filepath.Ext(filename) == ".rego" {
// TODO: support multiple rego files, need some way to identify the main policy file
if URI != "" {
return nil, fmt.Errorf("multiple policy files found in policy mapping")
}
URI = filePath
digest = map[string]string{"sha256": util.SHA256Hex(fileContents)}
}
}
policy := &Policy{
InputFiles: files,
Mapping: mapping,
URI: URI,
Digest: digest,
}
if imageName != matchedName {
policy.ResolvedName = matchedName
@@ -41,21 +55,34 @@ func resolveLocalPolicy(opts *Options, mapping *config.PolicyMapping, imageName
}
func resolveTUFPolicy(opts *Options, mapping *config.PolicyMapping, imageName string, matchedName string) (*Policy, error) {
var URI string
var digest map[string]string
files := make([]*File, 0, len(mapping.Files))
for _, f := range mapping.Files {
filename := f.Path
_, fileContents, err := opts.TUFClient.DownloadTarget(filename, filepath.Join(opts.LocalTargetsDir, filename))
file, err := opts.TUFClient.DownloadTarget(filename, filepath.Join(opts.LocalTargetsDir, filename))
if err != nil {
return nil, fmt.Errorf("failed to download policy file %s: %w", filename, err)
}
files = append(files, &File{
Path: filename,
Content: fileContents,
Content: file.Data,
})
// if the file is a policy file, store the URI and digest
if filepath.Ext(filename) == ".rego" {
// TODO: support multiple rego files, need some way to identify the main policy file
if URI != "" {
return nil, fmt.Errorf("multiple policy files found in policy mapping")
}
URI = file.TargetURI
digest = map[string]string{"sha256": file.Digest}
}
}
policy := &Policy{
InputFiles: files,
Mapping: mapping,
URI: URI,
Digest: digest,
}
if imageName != matchedName {
policy.ResolvedName = matchedName

2
pkg/policy/types.go
View File

@@ -40,6 +40,8 @@ type Policy struct {
Query string
Mapping *config.PolicyMapping
ResolvedName string
URI string
Digest map[string]string
}
type Input struct {

5
pkg/tuf/example_registry_test.go
View File

@@ -28,16 +28,13 @@ func ExampleNewClient_registry() {
// get trusted tuf metadata
trustedMetadata := registryClient.GetMetadata()
if err != nil {
panic(err)
}
// top-level target files
targets := trustedMetadata.Targets[metadata.TARGETS].Signed.Targets
for _, t := range targets {
// download target files
_, _, err := registryClient.DownloadTarget(t.Path, filepath.Join(tufOutputPath, "download"))
_, err := registryClient.DownloadTarget(t.Path, filepath.Join(tufOutputPath, "download"))
if err != nil {
panic(err)
}

12
pkg/tuf/mock.go
View File

@@ -24,10 +24,10 @@ func NewMockTufClient(srcPath string, dstPath string) *MockTufClient {
}
}
func (dc *MockTufClient) DownloadTarget(target string, filePath string) (actualFilePath string, data []byte, err error) {
func (dc *MockTufClient) DownloadTarget(target string, filePath string) (file *TargetFile, err error) {
src, err := os.Open(filepath.Join(dc.srcPath, target))
if err != nil {
return "", nil, err
return nil, err
}
defer src.Close()
@@ -40,11 +40,11 @@ func (dc *MockTufClient) DownloadTarget(target string, filePath string) (actualF
err = os.MkdirAll(filepath.Dir(dstFilePath), os.ModePerm)
if err != nil {
return "", nil, err
return nil, err
}
dst, err := os.Create(dstFilePath)
if err != nil {
return "", nil, err
return nil, err
}
defer dst.Close()
@@ -53,10 +53,10 @@ func (dc *MockTufClient) DownloadTarget(target string, filePath string) (actualF
b, err := io.ReadAll(tee)
if err != nil {
return "", nil, err
return nil, err
}
return dstFilePath, b, nil
return &TargetFile{ActualFilePath: dstFilePath, Data: b}, nil
}
type MockVersionChecker struct {

4
pkg/tuf/registry.go
View File

@@ -81,7 +81,7 @@ func NewRegistryFetcher(metadataRepo, metadataTag, targetsRepo string) *Registry
func (d *RegistryFetcher) DownloadFile(urlPath string, maxLength int64, timeout time.Duration) ([]byte, error) {
d.timeout = timeout
imgRef, fileName, err := d.parseImgRef(urlPath)
imgRef, fileName, err := d.ParseImgRef(urlPath)
if err != nil {
return nil, err
}
@@ -186,7 +186,7 @@ func getDataFromLayer(fileLayer v1.Layer, maxLength int64) ([]byte, error) {
}
// parseImgRef maintains the Fetcher interface by parsing a URL path to an image reference and file name.
func (d *RegistryFetcher) parseImgRef(urlPath string) (imgRef, fileName string, err error) {
func (d *RegistryFetcher) ParseImgRef(urlPath string) (imgRef, fileName string, err error) {
// Check if repo is target or metadata
if strings.Contains(urlPath, d.targetsRepo) {
// determine if the target path contains subdirectories and set image name accordingly

2
pkg/tuf/registry_test.go
View File

@@ -206,7 +206,7 @@ func TestParseImgRef(t *testing.T) {
metadataTag: LatestTag,
targetsRepo: targetsRepo,
}
imgRef, file, err := d.parseImgRef(tc.ref)
imgRef, file, err := d.ParseImgRef(tc.ref)
assert.NoError(t, err)
assert.Equal(t, tc.expectedRef, imgRef)
assert.Equal(t, tc.expectedFile, file)

60
pkg/tuf/tuf.go
View File

@@ -36,7 +36,7 @@ var (
)
type Downloader interface {
DownloadTarget(target, filePath string) (actualFilePath string, data []byte, err error)
DownloadTarget(target, filePath string) (file *TargetFile, err error)
}
type Client struct {
@@ -44,6 +44,13 @@ type Client struct {
cfg *config.UpdaterConfig
}
type TargetFile struct {
ActualFilePath string
TargetURI string
Digest string
Data []byte
}
// NewClient creates a new TUF client.
func NewClient(initialRoot []byte, tufPath, metadataSource, targetsSource string, versionChecker VersionChecker) (*Client, error) {
var tufSource Source
@@ -119,40 +126,73 @@ func NewClient(initialRoot []byte, tufPath, metadataSource, targetsSource string
return client, nil
}
func (t *Client) generateTargetURI(target *metadata.TargetFiles, digest string) (string, error) {
targetBaseURL := ensureTrailingSlash(t.cfg.RemoteTargetsURL)
targetRemotePath := target.Path
if t.cfg.PrefixTargetsWithHash {
baseName := filepath.Base(targetRemotePath)
dirName, ok := strings.CutSuffix(targetRemotePath, "/"+baseName)
if !ok {
// <hash>.<target-name>
targetRemotePath = fmt.Sprintf("%s.%s", digest, baseName)
} else {
// <dir-prefix>/<hash>.<target-name>
targetRemotePath = fmt.Sprintf("%s/%s.%s", dirName, digest, baseName)
}
}
fullURL := fmt.Sprintf("%s%s", targetBaseURL, targetRemotePath)
switch fetcher := t.cfg.Fetcher.(type) {
case *RegistryFetcher:
ref, _, err := fetcher.ParseImgRef(fullURL)
if err != nil {
return "", fmt.Errorf("failed to parse image reference: %w", err)
}
return ref, nil
case *fetcher.DefaultFetcher:
return fullURL, nil
default:
return "", fmt.Errorf("unsupported fetcher type: %T", fetcher)
}
}
// DownloadTarget downloads the target file using Updater. The Updater gets the target
// information, verifies if the target is already cached, and if it is not cached,
// downloads the target file.
func (t *Client) DownloadTarget(target string, filePath string) (actualFilePath string, data []byte, err error) {
func (t *Client) DownloadTarget(target string, filePath string) (file *TargetFile, err error) {
// search if the desired target is available
targetInfo, err := t.updater.GetTargetInfo(target)
if err != nil {
return "", nil, err
return nil, err
}
// check if filePath exists and create the directory if it doesn't
if _, err := os.Stat(filepath.Dir(filePath)); os.IsNotExist(err) {
err = os.MkdirAll(filepath.Dir(filePath), os.ModePerm)
if err != nil {
return "", nil, fmt.Errorf("failed to create target download directory '%s': %w", filepath.Dir(filePath), err)
return nil, fmt.Errorf("failed to create target download directory '%s': %w", filepath.Dir(filePath), err)
}
}
// target is available, so let's see if the target is already present locally
actualFilePath, data, err = t.updater.FindCachedTarget(targetInfo, filePath)
actualFilePath, data, err := t.updater.FindCachedTarget(targetInfo, filePath)
if err != nil {
return "", nil, fmt.Errorf("failed while finding a cached target: %w", err)
return nil, fmt.Errorf("failed while finding a cached target: %w", err)
}
if data != nil {
return actualFilePath, data, err
digest := util.SHA256Hex(data)
uri, err := t.generateTargetURI(targetInfo, digest)
return &TargetFile{ActualFilePath: actualFilePath, TargetURI: uri, Data: data, Digest: digest}, err
}
// target is not present locally, so let's try to download it
actualFilePath, data, err = t.updater.DownloadTarget(targetInfo, filePath, "")
if err != nil {
return "", nil, fmt.Errorf("failed to download target file %s - %w", target, err)
return nil, fmt.Errorf("failed to download target file %s - %w", target, err)
}
return actualFilePath, data, err
digest := util.SHA256Hex(data)
uri, err := t.generateTargetURI(targetInfo, digest)
return &TargetFile{ActualFilePath: actualFilePath, TargetURI: uri, Data: data, Digest: digest}, err
}
func (t *Client) GetMetadata() trustedmetadata.TrustedMetadata {

4
pkg/tuf/tuf_test.go
View File

@@ -122,14 +122,14 @@ func TestDownloadTarget(t *testing.T) {
targets := trustedMetadata.Targets[metadata.TARGETS].Signed.Targets
for _, target := range targets {
// download target files
_, _, err := tufClient.DownloadTarget(target.Path, filepath.Join(tufPath, "download"))
_, err := tufClient.DownloadTarget(target.Path, filepath.Join(tufPath, "download"))
assert.NoErrorf(t, err, "Failed to download target: %v", err)
}
// download delegated target
targetInfo, err := tufClient.updater.GetTargetInfo(delegatedTargetFile)
assert.NoError(t, err)
_, _, err = tufClient.DownloadTarget(targetInfo.Path, filepath.Join(tufPath, targetInfo.Path))
_, err = tufClient.DownloadTarget(targetInfo.Path, filepath.Join(tufPath, targetInfo.Path))
assert.NoError(t, err)
}
}

4
pkg/tuf/version.go
View File

@@ -67,11 +67,11 @@ func (vc *DefaultVersionChecker) CheckVersion(client Downloader) error {
// see https://github.com/Masterminds/semver/blob/v3.2.1/README.md#checking-version-constraints
// for more information on the expected format of the version constraints in the TUF repo
_, versionConstraintsBytes, err := client.DownloadTarget("version-constraints", "")
target, err := client.DownloadTarget("version-constraints", "")
if err != nil {
return fmt.Errorf("failed to download version-constraints: %w", err)
}
versionConstraints, err := semver.NewConstraint(string(versionConstraintsBytes))
versionConstraints, err := semver.NewConstraint(string(target.Data))
if err != nil {
return fmt.Errorf("failed to parse minimum version: %w", err)
}