feat(authz): service logic to use request auth as entity identifier in PDP decisions/entitlements (#2790)

### Proposed Changes

* pulls access token from context (where it was set by interceptors) in
PDP logic
* protovalidate tests for new proto

### Checklist

- [ ] I have added or updated unit tests
- [ ] I have added or updated integration tests (if appropriate)
- [ ] I have added or updated documentation

### Testing Instructions

Author: jakedoublev

service/authorization/v2/authorization_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/wrapperspb"
 )
 
 var (
@@ -141,6 +142,27 @@ var (
 			},
 			expectedValidationError: "entity_identifier",
 		},
+		{
+			name: "entity identifier - request token invalid",
+			request: &authzV2.GetDecisionMultiResourceRequest{
+				EntityIdentifier: &authzV2.EntityIdentifier{
+					Identifier: &authzV2.EntityIdentifier_WithRequestToken{
+						WithRequestToken: wrapperspb.Bool(false),
+					},
+				},
+				Action: sampleActionCreate,
+				Resources: []*authzV2.Resource{
+					{
+						Resource: &authzV2.Resource_AttributeValues_{
+							AttributeValues: &authzV2.Resource_AttributeValues{
+								Fqns: []string{sampleResourceFQN},
+							},
+						},
+					},
+				},
+			},
+			expectedValidationError: "entity_identifier",
+		},
 		{
 			name: "missing action",
 			request: &authzV2.GetDecisionMultiResourceRequest{
@@ -505,6 +527,24 @@ func Test_GetDecisionRequest_Succeeds(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "entity: use request token, action: create, resource: attribute values",
+			request: &authzV2.GetDecisionRequest{
+				EntityIdentifier: &authzV2.EntityIdentifier{
+					Identifier: &authzV2.EntityIdentifier_WithRequestToken{
+						WithRequestToken: wrapperspb.Bool(true),
+					},
+				},
+				Action: sampleActionCreate,
+				Resource: &authzV2.Resource{
+					Resource: &authzV2.Resource_AttributeValues_{
+						AttributeValues: &authzV2.Resource_AttributeValues{
+							Fqns: []string{sampleResourceFQN},
+						},
+					},
+				},
+			},
+		},
 		{
 			name: "entity: token, action: create, resource: registered",
 			request: &authzV2.GetDecisionRequest{
@@ -685,6 +725,44 @@ func Test_GetDecisionRequest_Fails(t *testing.T) {
 			},
 			expectedValidationError: "entity_identifier",
 		},
+		{
+			name: "entity identifier (request token) but nil",
+			request: &authzV2.GetDecisionRequest{
+				EntityIdentifier: &authzV2.EntityIdentifier{
+					Identifier: &authzV2.EntityIdentifier_WithRequestToken{
+						WithRequestToken: nil,
+					},
+				},
+				Action: sampleActionCreate,
+				Resource: &authzV2.Resource{
+					Resource: &authzV2.Resource_AttributeValues_{
+						AttributeValues: &authzV2.Resource_AttributeValues{
+							Fqns: []string{sampleResourceFQN},
+						},
+					},
+				},
+			},
+			expectedValidationError: "entity_identifier",
+		},
+		{
+			name: "entity identifier (request token) but false",
+			request: &authzV2.GetDecisionRequest{
+				EntityIdentifier: &authzV2.EntityIdentifier{
+					Identifier: &authzV2.EntityIdentifier_WithRequestToken{
+						WithRequestToken: wrapperspb.Bool(false),
+					},
+				},
+				Action: sampleActionCreate,
+				Resource: &authzV2.Resource{
+					Resource: &authzV2.Resource_AttributeValues_{
+						AttributeValues: &authzV2.Resource_AttributeValues{
+							Fqns: []string{sampleResourceFQN},
+						},
+					},
+				},
+			},
+			expectedValidationError: "entity_identifier",
+		},
 		{
 			name: "missing action",
 			request: &authzV2.GetDecisionRequest{

service/internal/access/v2/just_in_time_pdp.go

@@ -14,14 +14,20 @@ import (
 	"github.com/opentdf/platform/protocol/go/policy"
 	"github.com/opentdf/platform/protocol/go/policy/subjectmapping"
 	otdfSDK "github.com/opentdf/platform/sdk"
+	ctxAuth "github.com/opentdf/platform/service/pkg/auth"
+	"google.golang.org/protobuf/types/known/wrapperspb"
 
 	"github.com/opentdf/platform/service/internal/access/v2/obligations"
 	"github.com/opentdf/platform/service/logger"
 )
 
 var (
-	ErrMissingRequiredSDK = errors.New("access: missing required SDK")
-	ErrInvalidEntityType  = errors.New("access: invalid entity type")
+	ErrMissingRequiredSDK                       = errors.New("access: missing required SDK")
+	ErrInvalidEntityType                        = errors.New("access: invalid entity type")
+	ErrFailedToWithRequestTokenEntityIdentifier = errors.New("access: failed to use request token as entity identifier - none found in context")
+	ErrInvalidWithRequestTokenEntityIdentifier  = errors.New("access: invalid use request token as entity identifier - must be true if provided")
+
+	requestAuthTokenEphemeralID = "with-request-token-auth-entity"
 )
 
 type JustInTimePDP struct {
@@ -153,6 +159,9 @@ func (p *JustInTimePDP) GetDecision(
 	case *authzV2.EntityIdentifier_Token:
 		entityRepresentations, err = p.resolveEntitiesFromToken(ctx, entityIdentifier.GetToken(), skipEnvironmentEntities)
 
+	case *authzV2.EntityIdentifier_WithRequestToken:
+		entityRepresentations, err = p.resolveEntitiesFromRequestToken(ctx, entityIdentifier.GetWithRequestToken(), skipEnvironmentEntities)
+
 	case *authzV2.EntityIdentifier_RegisteredResourceValueFqn:
 		regResValueFQN := strings.ToLower(entityIdentifier.GetRegisteredResourceValueFqn())
 		// Registered resources do not have entity representations, so only one decision is made
@@ -246,6 +255,9 @@ func (p *JustInTimePDP) GetEntitlements(
 		// registered resources do not have entity representations, so we can skip the remaining logic
 		return p.pdp.GetEntitlementsRegisteredResource(ctx, regResValueFQN, withComprehensiveHierarchy)
 
+	case *authzV2.EntityIdentifier_WithRequestToken:
+		entityRepresentations, err = p.resolveEntitiesFromRequestToken(ctx, entityIdentifier.GetWithRequestToken(), skipEnvironmentEntities)
+
 	default:
 		return nil, fmt.Errorf("entity type %T: %w", entityIdentifier.GetIdentifier(), ErrInvalidEntityType)
 	}
@@ -366,3 +378,25 @@ func (p *JustInTimePDP) resolveEntitiesFromToken(
 	}
 	return p.resolveEntitiesFromEntityChain(ctx, entityChains[0], skipEnvironmentEntities)
 }
+
+// resolveEntitiesFromRequestToken pulls the request token off the context where it has been set upstream
+// by an interceptor and builds an entity.Token that it then resolves
+func (p *JustInTimePDP) resolveEntitiesFromRequestToken(
+	ctx context.Context,
+	withRequestToken *wrapperspb.BoolValue,
+	skipEnvironmentEntities bool,
+) ([]*entityresolutionV2.EntityRepresentation, error) {
+	if !withRequestToken.GetValue() {
+		return nil, ErrInvalidWithRequestTokenEntityIdentifier
+	}
+	rawToken := ctxAuth.GetRawAccessTokenFromContext(ctx, p.logger)
+	if rawToken == "" {
+		return nil, ErrFailedToWithRequestTokenEntityIdentifier
+	}
+	token := &entity.Token{
+		Jwt:         rawToken,
+		EphemeralId: requestAuthTokenEphemeralID,
+	}
+
+	return p.resolveEntitiesFromToken(ctx, token, skipEnvironmentEntities)
+}