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flex-auth/internal/adapters/rule/adapter.go
tegwick ad4895187b
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Add rule PDP adapter boundary
2026-05-17 07:13:27 +02:00

462 lines
16 KiB
Go

package rule
import (
"context"
"crypto/sha256"
"encoding/hex"
"encoding/json"
"fmt"
"reflect"
"github.com/netkingdom/flex-auth/internal/policy"
"github.com/netkingdom/flex-auth/pkg/api"
)
// Adapter wraps rule-PDP responses into flex-auth decision envelopes.
type Adapter struct {
backend Backend
backendName string
policyPackage string
policyVersion string
language Language
caring api.CaringPolicyMetadata
}
// New creates a delegated rule-PDP adapter.
func New(backend Backend, options Options) (*Adapter, error) {
if backend == nil {
return nil, fmt.Errorf("rule backend is required")
}
backendName := options.BackendName
if backendName == "" {
backendName = "rule"
}
language := options.Language
if language == "" {
language = LanguageRego
}
return &Adapter{
backend: backend,
backendName: backendName,
policyPackage: options.PolicyPackage,
policyVersion: options.PolicyVersion,
language: language,
caring: options.Caring,
}, nil
}
// Check evaluates one request through the delegated rule backend.
func (a *Adapter) Check(ctx context.Context, request api.CheckRequest) (api.DecisionEnvelope, error) {
evaluation, err := a.buildEvaluationRequest(request)
if err != nil {
return a.failureEnvelope(request, EvaluationRequest{}, FailureInvalidRequest, err), nil
}
result, err := a.backend.Evaluate(ctx, evaluation)
if err != nil {
return a.failureEnvelope(request, evaluation, failureKind(err), err), nil
}
if result.StalePolicy {
return a.failureEnvelope(request, evaluation, FailureStalePolicy, nil), nil
}
if result.PartialResult {
return a.failureEnvelope(request, evaluation, FailurePartialResult, nil), nil
}
return a.envelope(request, evaluation, result), nil
}
// BatchCheck evaluates resources in request order.
func (a *Adapter) BatchCheck(ctx context.Context, request api.BatchCheckRequest) ([]api.DecisionEnvelope, error) {
evaluations := make([]EvaluationRequest, 0, len(request.Resources))
checks := make([]api.CheckRequest, 0, len(request.Resources))
for _, resource := range request.Resources {
check := api.CheckRequest{
ID: request.ID,
Subject: request.Subject,
Action: request.Action,
Resource: resource,
Context: request.Context,
PolicyVersion: request.PolicyVersion,
}
evaluation, err := a.buildEvaluationRequest(check)
if err != nil {
return []api.DecisionEnvelope{a.failureEnvelope(check, EvaluationRequest{}, FailureInvalidRequest, err)}, nil
}
evaluations = append(evaluations, evaluation)
checks = append(checks, check)
}
results, err := a.backend.BatchEvaluate(ctx, evaluations)
if err != nil {
decisions := make([]api.DecisionEnvelope, 0, len(checks))
for i, check := range checks {
decisions = append(decisions, a.failureEnvelope(check, evaluations[i], failureKind(err), err))
}
return decisions, nil
}
if len(results) != len(checks) {
decisions := make([]api.DecisionEnvelope, 0, len(checks))
for i, check := range checks {
decisions = append(decisions, a.failureEnvelope(check, evaluations[i], FailurePartialResult, nil))
}
return decisions, nil
}
decisions := make([]api.DecisionEnvelope, 0, len(results))
for i, result := range results {
if result.StalePolicy {
decisions = append(decisions, a.failureEnvelope(checks[i], evaluations[i], FailureStalePolicy, nil))
continue
}
if result.PartialResult {
decisions = append(decisions, a.failureEnvelope(checks[i], evaluations[i], FailurePartialResult, nil))
continue
}
decisions = append(decisions, a.envelope(checks[i], evaluations[i], result))
}
return decisions, nil
}
// ImportPolicy imports a flex-auth Rego-in-Markdown package as a delegated
// rule artifact.
func (a *Adapter) ImportPolicy(ctx context.Context, pkg *policy.Package) (PolicyImportReport, error) {
if pkg == nil {
return PolicyImportReport{}, fmt.Errorf("policy package is required")
}
artifact := PolicyArtifactFromPackage(pkg)
report, err := a.backend.ImportPolicy(ctx, artifact)
if err != nil {
return PolicyImportReport{}, err
}
a.policyPackage = artifact.ID
a.policyVersion = artifact.Version
a.language = artifact.Language
a.caring = artifact.Caring
return report, nil
}
// EvaluateFixtures runs policy fixtures through the delegated backend.
func (a *Adapter) EvaluateFixtures(ctx context.Context, fixtures []api.PolicyFixture) []FixtureResult {
results := make([]FixtureResult, 0, len(fixtures))
for _, fixture := range fixtures {
decision, err := a.Check(ctx, fixture.Request)
actual := api.DecisionExpectation{}
if err == nil {
actual = api.DecisionExpectation{
Effect: decision.Effect,
Reason: decision.Reason,
Obligations: decision.Obligations,
ConformanceFindings: conformanceFindings(decision),
}
}
result := FixtureResult{
ID: fixture.ID,
Expected: fixture.Expect,
Actual: actual,
Passed: err == nil && expectationMatches(fixture.Expect, actual),
}
if err != nil {
result.Error = err.Error()
}
results = append(results, result)
}
return results
}
func (a *Adapter) buildEvaluationRequest(request api.CheckRequest) (EvaluationRequest, error) {
if request.Subject.ID == "" || request.Action == "" || request.Resource.ID == "" {
return EvaluationRequest{}, fmt.Errorf("subject id, action, and resource id are required")
}
policyVersion := firstNonEmpty(request.PolicyVersion, a.policyVersion)
evaluation := EvaluationRequest{
ID: request.ID,
Subject: request.Subject,
Action: request.Action,
Resource: request.Resource,
Context: copyMap(request.Context),
CaringContext: request.CaringContext,
PolicyPackage: a.policyPackage,
PolicyVersion: policyVersion,
Language: a.language,
}
evaluation.Input = CanonicalInput(evaluation)
return evaluation, nil
}
// CanonicalInput returns the policy-language-neutral input shape.
func CanonicalInput(request EvaluationRequest) map[string]any {
input := map[string]any{
"subject": request.Subject,
"action": request.Action,
"resource": request.Resource,
"context": copyMap(request.Context),
"policy": map[string]any{
"package": request.PolicyPackage,
"version": request.PolicyVersion,
},
}
if request.CaringContext != nil {
input["caring_context"] = request.CaringContext
}
return input
}
func (a *Adapter) envelope(request api.CheckRequest, evaluation EvaluationRequest, result EvaluationResult) api.DecisionEnvelope {
effect := result.Effect
if effect == "" {
effect = api.DecisionEffectDeny
}
reason := result.Reason
if reason == "" {
reason = string(effect)
}
policyPackage := firstNonEmpty(result.PolicyPackage, a.policyPackage)
policyVersion := firstNonEmpty(result.PolicyVersion, evaluation.PolicyVersion, a.policyVersion)
diagnostics := copyMap(result.Diagnostics)
addRuleDiagnostics(diagnostics, a.backendName, evaluation, "")
envelope := api.DecisionEnvelope{
RequestID: request.ID,
Effect: effect,
Reason: reason,
MatchedPolicyVersion: policyVersion,
MatchedRule: firstNonEmpty(result.MatchedRule, reason),
Resource: request.Resource,
Subject: request.Subject,
Obligations: append([]api.Obligation(nil), result.Obligations...),
Diagnostics: diagnostics,
Provenance: api.DecisionProvenance{
Evaluator: EvaluatorName + "/" + a.backendName,
Mode: DelegatedMode,
PolicyPackage: policyPackage,
PolicyVersion: policyVersion,
},
Caring: caringDecisionMetadata(request, firstDescriptor(request.CaringContext, result.CaringDescriptor), a.caring, result.ConformanceFindings),
}
envelope.ID = decisionID(a.backendName, policyPackage, policyVersion, request, effect, reason)
return envelope
}
func (a *Adapter) failureEnvelope(request api.CheckRequest, evaluation EvaluationRequest, kind FailureKind, err error) api.DecisionEnvelope {
reason := failureReason(kind)
policyVersion := firstNonEmpty(request.PolicyVersion, a.policyVersion)
envelope := api.DecisionEnvelope{
RequestID: request.ID,
Effect: api.DecisionEffectDeny,
Reason: reason,
MatchedPolicyVersion: policyVersion,
MatchedRule: reason,
Resource: request.Resource,
Subject: request.Subject,
Diagnostics: failureDiagnostics(a.backendName, evaluation, kind, err),
Provenance: api.DecisionProvenance{
Evaluator: EvaluatorName + "/" + a.backendName,
Mode: DelegatedMode,
PolicyPackage: a.policyPackage,
PolicyVersion: policyVersion,
},
Caring: caringDecisionMetadata(request, request.CaringContext, a.caring, []api.CaringConformanceFinding{failureFinding(kind)}),
}
envelope.ID = decisionID(a.backendName, a.policyPackage, policyVersion, request, envelope.Effect, envelope.Reason)
return envelope
}
func caringDecisionMetadata(
request api.CheckRequest,
descriptor *api.CaringAccessDescriptor,
policyMetadata api.CaringPolicyMetadata,
findings []api.CaringConformanceFinding,
) *api.CaringDecisionMetadata {
profile := firstNonEmpty(policyMetadata.Profile, api.CaringProfileCaring040RC2)
if descriptor != nil && descriptor.Profile != "" {
profile = descriptor.Profile
}
metadata := &api.CaringDecisionMetadata{
Profile: profile,
ConformanceFindings: append([]api.CaringConformanceFinding(nil), findings...),
}
metadata.ConformanceFindings = append(metadata.ConformanceFindings, policyMetadataFindings(policyMetadata)...)
if descriptor == nil {
metadata.ConformanceFindings = append(metadata.ConformanceFindings, api.CaringConformanceFinding{
Code: "RULE-CARING-DESCRIPTOR-MISSING",
Severity: "warning",
Message: "delegated rule backend result did not include a CARING descriptor",
Fields: []string{"caring_context"},
})
return metadata
}
descriptorCopy := *descriptor
metadata.Descriptor = &descriptorCopy
metadata.RestrictionsEvaluated = append([]api.Restriction(nil), descriptor.Restrictions...)
metadata.ExposureModes = append([]api.ExposureMode(nil), descriptor.ExposureModes...)
metadata.DerivedCapabilities = append([]api.CaringDerivedCapability(nil), descriptor.DerivedCapabilities...)
if descriptor.ExposureEvent != "" {
scope := descriptor.Scope
metadata.ExposureEvent = &api.CaringExposureEvent{
ID: decisionID("rule", "", "", request, api.DecisionEffectAllow, string(descriptor.ExposureEvent)),
Type: descriptor.ExposureEvent,
Actor: request.Subject.ID,
Subject: request.Subject.ID,
Descriptor: &descriptorCopy,
Scope: &scope,
Planes: append([]api.Plane(nil), descriptor.Planes...),
CapabilitiesUsed: append([]api.Capability(nil), descriptor.Capabilities...),
ExposureModes: append([]api.ExposureMode(nil), descriptor.ExposureModes...),
Reason: "delegated rule decision carries CARING exposure event hook",
AuthoritySource: EvaluatorName,
}
}
return metadata
}
func policyMetadataFindings(metadata api.CaringPolicyMetadata) []api.CaringConformanceFinding {
if metadata.Profile == "" {
return nil
}
var findings []api.CaringConformanceFinding
addMissing := func(empty bool, field, label string) {
if empty {
findings = append(findings, api.CaringConformanceFinding{
Code: "RULE-CARING-METADATA-GAP",
Severity: "warning",
Message: "backend-native rule artifact does not directly represent CARING " + label,
Fields: []string{field},
})
}
}
addMissing(len(metadata.CanonicalRoles) == 0, "caring.canonical_roles", "canonical roles")
addMissing(len(metadata.OrganizationRelations) == 0, "caring.organization_relations", "organization relations")
addMissing(len(metadata.Scopes) == 0, "caring.scopes", "scopes")
addMissing(len(metadata.Planes) == 0, "caring.planes", "planes")
addMissing(len(metadata.Capabilities) == 0, "caring.capabilities", "capabilities")
addMissing(len(metadata.ExposureModes) == 0, "caring.exposure_modes", "exposure modes")
return findings
}
func failureDiagnostics(backendName string, request EvaluationRequest, kind FailureKind, err error) map[string]any {
diagnostics := map[string]any{}
addRuleDiagnostics(diagnostics, backendName, request, string(kind))
if err != nil {
diagnostics["error"] = err.Error()
}
return diagnostics
}
func addRuleDiagnostics(diagnostics map[string]any, backendName string, request EvaluationRequest, failure string) {
diagnostics["adapter"] = "rule"
diagnostics["backend"] = backendName
diagnostics["mode"] = DelegatedMode
diagnostics["language"] = string(request.Language)
if failure != "" {
diagnostics["rule_failure"] = failure
}
if request.PolicyPackage != "" {
diagnostics["policy_package"] = request.PolicyPackage
diagnostics["policy_version"] = request.PolicyVersion
}
}
func failureReason(kind FailureKind) string {
switch kind {
case FailureStalePolicy:
return "rule_policy_stale"
case FailurePartialResult:
return "rule_partial_result"
case FailureInvalidRequest:
return "rule_request_incomplete"
case FailureUnsupportedPolicy:
return "rule_policy_unsupported"
default:
return "rule_backend_unavailable"
}
}
func failureFinding(kind FailureKind) api.CaringConformanceFinding {
code := "RULE-BACKEND-UNAVAILABLE"
message := "Rule backend was unavailable; flex-auth denied the delegated request fail-closed."
switch kind {
case FailureStalePolicy:
code = "RULE-POLICY-STALE"
message = "Rule backend policy version was stale; flex-auth denied fail-closed."
case FailurePartialResult:
code = "RULE-PARTIAL-RESULT"
message = "Rule backend returned a partial result; flex-auth denied fail-closed."
case FailureInvalidRequest:
code = "RULE-REQUEST-INCOMPLETE"
message = "Request could not be translated to canonical rule input; flex-auth denied fail-closed."
case FailureUnsupportedPolicy:
code = "RULE-POLICY-UNSUPPORTED"
message = "Rule backend cannot represent the imported policy artifact; flex-auth denied fail-closed."
}
return api.CaringConformanceFinding{Code: code, Severity: "error", Message: message}
}
func conformanceFindings(decision api.DecisionEnvelope) []api.CaringConformanceFinding {
if decision.Caring == nil {
return nil
}
return decision.Caring.ConformanceFindings
}
func expectationMatches(expected, actual api.DecisionExpectation) bool {
if expected.Effect != actual.Effect {
return false
}
if expected.Reason != "" && expected.Reason != actual.Reason {
return false
}
if len(expected.Obligations) > 0 && !reflect.DeepEqual(expected.Obligations, actual.Obligations) {
return false
}
return true
}
func firstDescriptor(values ...*api.CaringAccessDescriptor) *api.CaringAccessDescriptor {
for _, value := range values {
if value != nil {
return value
}
}
return nil
}
func decisionID(backendName, policyPackage, policyVersion string, request api.CheckRequest, effect api.DecisionEffect, reason string) string {
data, _ := json.Marshal(struct {
Adapter string `json:"adapter"`
Backend string `json:"backend"`
PolicyPackage string `json:"policy_package,omitempty"`
PolicyVersion string `json:"policy_version,omitempty"`
Request api.CheckRequest `json:"request"`
Effect api.DecisionEffect `json:"effect"`
Reason string `json:"reason"`
}{
Adapter: EvaluatorName,
Backend: backendName,
PolicyPackage: policyPackage,
PolicyVersion: policyVersion,
Request: request,
Effect: effect,
Reason: reason,
})
sum := sha256.Sum256(data)
return "decision:rule:" + hex.EncodeToString(sum[:8])
}
func firstNonEmpty(values ...string) string {
for _, value := range values {
if value != "" {
return value
}
}
return ""
}
func copyMap(in map[string]any) map[string]any {
out := make(map[string]any, len(in))
for key, value := range in {
out[key] = value
}
return out
}