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Add record-level authorization for system accounts

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Record mutations (create, update, delete) no longer require admin role.
Authorization rules:
  - admin: full access (unchanged)
  - system mcp-agent: create/delete any record
  - system account α: create/delete records named α only
  - human users: read-only (unchanged)

Zone mutations remain admin-only. Both REST and gRPC paths enforce the
same rules. Update checks authorization against both old and new names.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
Kyle Isom
2026-03-28 15:52:43 -07:00
parent baa058d4a4
commit 871b1fb8f4
7 changed files with 120 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
internal/grpcserver/handlers_test.go
View File

@@ -769,6 +769,9 @@ func TestMethodMapCompleteness(t *testing.T) {
"/mcns.v1.ZoneService/GetZone",
"/mcns.v1.RecordService/ListRecords",
"/mcns.v1.RecordService/GetRecord",
"/mcns.v1.RecordService/CreateRecord",
"/mcns.v1.RecordService/UpdateRecord",
"/mcns.v1.RecordService/DeleteRecord",
}
for _, method := range expectedAuth {
if !mm.AuthRequired[method] {
@@ -783,9 +786,6 @@ func TestMethodMapCompleteness(t *testing.T) {
"/mcns.v1.ZoneService/CreateZone",
"/mcns.v1.ZoneService/UpdateZone",
"/mcns.v1.ZoneService/DeleteZone",
"/mcns.v1.RecordService/CreateRecord",
"/mcns.v1.RecordService/UpdateRecord",
"/mcns.v1.RecordService/DeleteRecord",
}
for _, method := range expectedAdmin {
if !mm.AdminRequired[method] {

6
internal/grpcserver/interceptors.go
View File

@@ -30,6 +30,9 @@ func authRequiredMethods() map[string]bool {
"/mcns.v1.ZoneService/GetZone": true,
"/mcns.v1.RecordService/ListRecords": true,
"/mcns.v1.RecordService/GetRecord": true,
"/mcns.v1.RecordService/CreateRecord": true,
"/mcns.v1.RecordService/UpdateRecord": true,
"/mcns.v1.RecordService/DeleteRecord": true,
}
}
@@ -38,8 +41,5 @@ func adminRequiredMethods() map[string]bool {
"/mcns.v1.ZoneService/CreateZone": true,
"/mcns.v1.ZoneService/UpdateZone": true,
"/mcns.v1.ZoneService/DeleteZone": true,
"/mcns.v1.RecordService/CreateRecord": true,
"/mcns.v1.RecordService/UpdateRecord": true,
"/mcns.v1.RecordService/DeleteRecord": true,
}
}

50
internal/grpcserver/records.go
View File

@@ -10,10 +10,36 @@ import (
"google.golang.org/grpc/status"
"google.golang.org/protobuf/types/known/timestamppb"
mcdslauth "git.wntrmute.dev/mc/mcdsl/auth"
mcdslgrpc "git.wntrmute.dev/mc/mcdsl/grpcserver"
pb "git.wntrmute.dev/mc/mcns/gen/mcns/v1"
"git.wntrmute.dev/mc/mcns/internal/db"
)
// authorizeRecordMutation checks whether the caller may create, update,
// or delete a DNS record with the given name. The rules are:
//
// - admin role: always allowed
// - system account "mcp-agent": allowed for any record name
// - system account α: allowed only when recordName == α
// - all others: denied
func authorizeRecordMutation(info *mcdslauth.TokenInfo, recordName string) bool {
if info == nil {
return false
}
if info.IsAdmin {
return true
}
if info.AccountType != "system" {
return false
}
if info.Username == "mcp-agent" {
return true
}
return recordName == info.Username
}
type recordService struct {
pb.UnimplementedRecordServiceServer
db *db.DB
@@ -55,7 +81,7 @@ func (s *recordService) GetRecord(_ context.Context, req *pb.GetRecordRequest) (
return s.recordToProto(*record), nil
}
func (s *recordService) CreateRecord(_ context.Context, req *pb.CreateRecordRequest) (*pb.Record, error) {
func (s *recordService) CreateRecord(ctx context.Context, req *pb.CreateRecordRequest) (*pb.Record, error) {
if req.Zone == "" {
return nil, status.Error(codes.InvalidArgument, "zone is required")
}
@@ -69,6 +95,10 @@ func (s *recordService) CreateRecord(_ context.Context, req *pb.CreateRecordRequ
return nil, status.Error(codes.InvalidArgument, "value is required")
}
if !authorizeRecordMutation(mcdslgrpc.TokenInfoFromContext(ctx), req.Name) {
return nil, status.Error(codes.PermissionDenied, "not authorized for record name")
}
record, err := s.db.CreateRecord(req.Zone, req.Name, req.Type, req.Value, int(req.Ttl))
if errors.Is(err, db.ErrNotFound) {
return nil, status.Error(codes.NotFound, "zone not found")
@@ -82,7 +112,7 @@ func (s *recordService) CreateRecord(_ context.Context, req *pb.CreateRecordRequ
return s.recordToProto(*record), nil
}
func (s *recordService) UpdateRecord(_ context.Context, req *pb.UpdateRecordRequest) (*pb.Record, error) {
func (s *recordService) UpdateRecord(ctx context.Context, req *pb.UpdateRecordRequest) (*pb.Record, error) {
if req.Id <= 0 {
return nil, status.Error(codes.InvalidArgument, "id must be positive")
}
@@ -96,6 +126,15 @@ func (s *recordService) UpdateRecord(_ context.Context, req *pb.UpdateRecordRequ
return nil, status.Error(codes.InvalidArgument, "value is required")
}
info := mcdslgrpc.TokenInfoFromContext(ctx)
existing, lookupErr := s.db.GetRecord(req.Id)
if lookupErr == nil && !authorizeRecordMutation(info, existing.Name) {
return nil, status.Error(codes.PermissionDenied, "not authorized for record name")
}
if !authorizeRecordMutation(info, req.Name) {
return nil, status.Error(codes.PermissionDenied, "not authorized for record name")
}
record, err := s.db.UpdateRecord(req.Id, req.Name, req.Type, req.Value, int(req.Ttl))
if errors.Is(err, db.ErrNotFound) {
return nil, status.Error(codes.NotFound, "record not found")
@@ -109,11 +148,16 @@ func (s *recordService) UpdateRecord(_ context.Context, req *pb.UpdateRecordRequ
return s.recordToProto(*record), nil
}
func (s *recordService) DeleteRecord(_ context.Context, req *pb.DeleteRecordRequest) (*pb.DeleteRecordResponse, error) {
func (s *recordService) DeleteRecord(ctx context.Context, req *pb.DeleteRecordRequest) (*pb.DeleteRecordResponse, error) {
if req.Id <= 0 {
return nil, status.Error(codes.InvalidArgument, "id must be positive")
}
existing, lookupErr := s.db.GetRecord(req.Id)
if lookupErr == nil && !authorizeRecordMutation(mcdslgrpc.TokenInfoFromContext(ctx), existing.Name) {
return nil, status.Error(codes.PermissionDenied, "not authorized for record name")
}
err := s.db.DeleteRecord(req.Id)
if errors.Is(err, db.ErrNotFound) {
return nil, status.Error(codes.NotFound, "record not found")

12
internal/server/handlers_test.go
View File

@@ -42,6 +42,7 @@ func createTestZone(t *testing.T, database *db.DB) *db.Zone {
}
// newChiRequest builds a request with chi URL params injected into the context.
// An admin TokenInfo is added so that handler-level authorization passes.
func newChiRequest(method, target string, body string, params map[string]string) *http.Request {
var r *http.Request
if body != "" {
@@ -51,14 +52,21 @@ func newChiRequest(method, target string, body string, params map[string]string)
}
r.Header.Set("Content-Type", "application/json")
ctx := r.Context()
if len(params) > 0 {
rctx := chi.NewRouteContext()
for k, v := range params {
rctx.URLParams.Add(k, v)
}
r = r.WithContext(context.WithValue(r.Context(), chi.RouteCtxKey, rctx))
ctx = context.WithValue(ctx, chi.RouteCtxKey, rctx)
}
return r
// Inject admin TokenInfo for handler-level authorization.
ctx = context.WithValue(ctx, tokenInfoKey, &mcdslauth.TokenInfo{
Username: "testadmin",
IsAdmin: true,
})
return r.WithContext(ctx)
}
// decodeJSON decodes the response body into v.

23
internal/server/middleware.go
View File

@@ -48,6 +48,29 @@ func requireAdmin(next http.Handler) http.Handler {
})
}
// authorizeRecordMutation checks whether the caller may create, update,
// or delete a DNS record with the given name. The rules are:
//
// - admin role: always allowed
// - system account "mcp-agent": allowed for any record name
// - system account α: allowed only when recordName == α
// - all others: denied
func authorizeRecordMutation(info *mcdslauth.TokenInfo, recordName string) bool {
if info == nil {
return false
}
if info.IsAdmin {
return true
}
if info.AccountType != "system" {
return false
}
if info.Username == "mcp-agent" {
return true
}
return recordName == info.Username
}
// tokenInfoFromContext extracts the TokenInfo from the request context.
func tokenInfoFromContext(ctx context.Context) *mcdslauth.TokenInfo {
info, _ := ctx.Value(tokenInfoKey).(*mcdslauth.TokenInfo)

24
internal/server/records.go
View File

@@ -86,6 +86,11 @@ func createRecordHandler(database *db.DB) http.HandlerFunc {
return
}
if !authorizeRecordMutation(tokenInfoFromContext(r.Context()), req.Name) {
writeError(w, http.StatusForbidden, "not authorized for record name")
return
}
record, err := database.CreateRecord(zoneName, req.Name, req.Type, req.Value, req.TTL)
if errors.Is(err, db.ErrNotFound) {
writeError(w, http.StatusNotFound, "zone not found")
@@ -132,6 +137,18 @@ func updateRecordHandler(database *db.DB) http.HandlerFunc {
return
}
// Authorize against both old and new record names.
info := tokenInfoFromContext(r.Context())
existing, lookupErr := database.GetRecord(id)
if lookupErr == nil && !authorizeRecordMutation(info, existing.Name) {
writeError(w, http.StatusForbidden, "not authorized for record name")
return
}
if !authorizeRecordMutation(info, req.Name) {
writeError(w, http.StatusForbidden, "not authorized for record name")
return
}
record, err := database.UpdateRecord(id, req.Name, req.Type, req.Value, req.TTL)
if errors.Is(err, db.ErrNotFound) {
writeError(w, http.StatusNotFound, "record not found")
@@ -159,6 +176,13 @@ func deleteRecordHandler(database *db.DB) http.HandlerFunc {
return
}
// Look up the record to authorize by name.
existing, lookupErr := database.GetRecord(id)
if lookupErr == nil && !authorizeRecordMutation(tokenInfoFromContext(r.Context()), existing.Name) {
writeError(w, http.StatusForbidden, "not authorized for record name")
return
}
err = database.DeleteRecord(id)
if errors.Is(err, db.ErrNotFound) {
writeError(w, http.StatusNotFound, "record not found")

10
internal/server/routes.go
View File

@@ -44,14 +44,14 @@ func NewRouter(deps Deps) *chi.Mux {
r.With(requireAdmin).Put("/v1/zones/{zone}", updateZoneHandler(deps.DB))
r.With(requireAdmin).Delete("/v1/zones/{zone}", deleteZoneHandler(deps.DB))
// Record endpoints — reads for all authenticated users, writes for admin.
// Record endpoints — reads for all authenticated users.
r.Get("/v1/zones/{zone}/records", listRecordsHandler(deps.DB))
r.Get("/v1/zones/{zone}/records/{id}", getRecordHandler(deps.DB))
// Admin-only record mutations.
r.With(requireAdmin).Post("/v1/zones/{zone}/records", createRecordHandler(deps.DB))
r.With(requireAdmin).Put("/v1/zones/{zone}/records/{id}", updateRecordHandler(deps.DB))
r.With(requireAdmin).Delete("/v1/zones/{zone}/records/{id}", deleteRecordHandler(deps.DB))
// Record mutations — admin, mcp-agent (any name), or system account (own name).
r.Post("/v1/zones/{zone}/records", createRecordHandler(deps.DB))
r.Put("/v1/zones/{zone}/records/{id}", updateRecordHandler(deps.DB))
r.Delete("/v1/zones/{zone}/records/{id}", deleteRecordHandler(deps.DB))
})
return r