Add authorization framework for gRPC methods

client/cmd/service.go

@@ -46,7 +46,7 @@ type program struct {
 	jsonServMu       sync.Mutex
 	serverInstance   *server.Server
 	serverInstanceMu sync.Mutex
-	ruleGate         *ipcauth.RuleGate
+	authzGate        *ipcauth.AuthzGate
 }
 
 func init() {

client/cmd/service_controller.go

@@ -80,12 +80,12 @@ func (p *program) Start(svc service.Service) error {
 		return fmt.Errorf("parse daemon address: %w", err)
 	}
 
-	p.ruleGate = ipcauth.NewRuleGate()
+	p.authzGate = ipcauth.NewAuthzGate()
 
 	// in any case, even if configuration does not exists we run daemon to serve CLI gRPC API.
 	opts := append(daemonServerOptions(network),
-		grpc.ChainUnaryInterceptor(p.ruleGate.UnaryPolicyInterceptor()),
-		grpc.ChainStreamInterceptor(p.ruleGate.StreamPolicyInterceptor()),
+		grpc.ChainUnaryInterceptor(p.authzGate.UnaryPolicyInterceptor()),
+		grpc.ChainStreamInterceptor(p.authzGate.StreamPolicyInterceptor()),
 	)
 	p.serv = grpc.NewServer(opts...)
 
@@ -151,7 +151,7 @@ func (p *program) serve(daemonListener, jsonListener *socketListener) error {
 	}
 
 	serverInstance := server.New(p.ctx, util.FindFirstLogPath(logFiles), configPath, profilesDisabled, updateSettingsDisabled, captureEnabled, networksDisabled)
-	p.ruleGate.SetState(serverInstance)
+	p.authzGate.SetState(serverInstance)
 	if err := serverInstance.Start(); err != nil {
 		return fmt.Errorf("start daemon: %w", err)
 	}

client/internal/ipcauth/authz_gate.go

@@ -0,0 +1,167 @@
+package ipcauth
+
+import (
+	"context"
+	"sync"
+
+	log "github.com/sirupsen/logrus"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// DaemonState is used to surface the server state needed for determining
+// authorization.
+type DaemonState interface {
+	// SessionHolder returns the principal entitled to the live connection and
+	// whether one is held.
+	SessionHolder() (Principal, bool)
+
+	OwnsProfile(id Identity, handle string) bool
+}
+
+// AuthzGate authorizes every RPC call before its handler run.
+type AuthzGate struct {
+	mu sync.Mutex
+	st DaemonState
+}
+
+// NewAuthzGate returns a gate with no state attached.
+func NewAuthzGate() *AuthzGate {
+	return &AuthzGate{}
+}
+
+// SetState attaches the daemon state. Musy be called before serving RPCs.
+func (g *AuthzGate) SetState(st DaemonState) {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	g.st = st
+}
+
+func (g *AuthzGate) state() DaemonState {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	return g.st
+}
+
+// RequireHolderForFullStatus is a Rule that enforces the right AuthzLevel if
+// "full status" or "should run probes" are requested in a StatusRequest.
+func RequireHolderForFullStatus(r Request) error {
+	full, ok := r.Msg.(interface{ GetGetFullPeerStatus() bool })
+	if !ok || !full.GetGetFullPeerStatus() {
+		return nil
+	}
+	probes, ok := r.Msg.(interface{ ShouldRunProbes() bool })
+	if !ok || !probes.ShouldRunProbes() {
+		return nil
+	}
+	return RequireLevel(AuthzLevelSessionHolder)(r)
+}
+
+// RequireLevel builds a rule from a level, for composing inside another rule.
+func RequireLevel(want AuthzLevel) Rule {
+	return func(r Request) error {
+		if r.Level >= want {
+			return nil
+		}
+		return denyLevel(r, want)
+	}
+}
+
+// RequireFlowInitiator binds a pending authentication flow to the identity that
+// started it.
+func RequireFlowInitiator(r Request) error {
+	// TODO: needs the flow registry keyed by initiator.
+	return status.Error(codes.Unimplemented, "pending flows are not yet caller-bound")
+}
+
+func denyLevel(r Request, want AuthzLevel) error {
+	return status.Errorf(codes.PermissionDenied,
+		"%s requires %s, caller %s is %s", r.Method, want, r.Identity, r.Level)
+}
+
+// StreamPolicyInterceptor authorizes each streaming RPC before the handler runs.
+// The request payload is not yet available, so no streaming method may be
+// target-scoped.
+func (g *AuthzGate) StreamPolicyInterceptor() grpc.StreamServerInterceptor {
+	return func(srv any, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+		authCtx, authErr := g.authorize(ss.Context(), info.FullMethod, nil)
+		if authErr != nil {
+			return authErr
+		}
+		return handler(srv, &authorizedStream{ServerStream: ss, ctx: authCtx})
+	}
+}
+
+// UnaryPolicyInterceptor authorizes each unary RPC before the handler runs.
+func (g *AuthzGate) UnaryPolicyInterceptor() grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp any, err error) {
+		authCtx, authErr := g.authorize(ctx, info.FullMethod, req)
+		if authErr != nil {
+			return nil, authErr
+		}
+		return handler(authCtx, req)
+	}
+}
+
+func (g *AuthzGate) authorize(ctx context.Context, method string, msg any) (context.Context, error) {
+	id, ok := CallerIdentity(ctx)
+	if !ok {
+		log.Warnf("ipc authz: DENY %s, caller identity unavailable", method)
+		return nil, status.Error(codes.PermissionDenied,
+			"caller identity could not be verified on the daemon control channel")
+	}
+	st := g.state()
+	if st == nil {
+		log.Warnf("ipc authz: DENY %s for %s, daemon state not attached", method, id)
+		return nil, status.Error(codes.Unavailable, "daemon not initialized")
+	}
+	target, named := targetProfile(msg)
+	policy := methodPolicyFor(method)
+	if policy.TargetsProfile && !named {
+		return nil, status.Errorf(codes.Internal, "%s is declared target-scoped but names no profile", method)
+	}
+	auth := Authorization{
+		Identity: id,
+		Level:    resolveLevel(id, target, st),
+		Target:   target,
+		Method:   method,
+	}
+	req := Request{Authorization: auth, State: st, Msg: msg}
+	if req.Level < policy.Level {
+		log.Warnf("ipc authz: DENY %s for %s (%s), requires %s", method, id, req.Level, policy.Level)
+		return nil, denyLevel(req, policy.Level)
+	}
+	for _, rule := range policy.Rules {
+		if err := rule(req); err != nil {
+			log.Warnf("ipc authz: DENY %s for %s (%s): %v", method, id, req.Level, err)
+			return nil, err
+		}
+	}
+	if policy.Audit {
+		log.Infof("ipc authz: allow %s for %s (%s)", method, id, req.Level)
+	}
+	return withAuthorization(ctx, auth), nil
+}
+
+// authorizedStream carries the authorized context into a streaming handler,
+// which would otherwise see the one the stream was created with.
+type authorizedStream struct {
+	grpc.ServerStream
+	ctx context.Context
+}
+
+type authorizationKey struct{}
+
+func withAuthorization(ctx context.Context, a Authorization) context.Context {
+	return context.WithValue(ctx, authorizationKey{}, a)
+}
+
+// Authorized returns the decision the interceptor made for this RPC.
+//
+// Read it to decide what a caller sees or who an action is attributed to. Do not
+// read it to decide whether a call is allowed, which is the method table's job.
+func Authorized(ctx context.Context) Authorization {
+	a, _ := ctx.Value(authorizationKey{}).(Authorization)
+	return a
+}

client/internal/ipcauth/authz_level.go

@@ -0,0 +1,59 @@
+package ipcauth
+
+// AuthzLevel is the authority a caller holds over the daemon's current state.
+// The values are ordered, and each level can do everything the levles below
+// it can. A MethodPolicy is satisfied when the caller's level is at least
+// the level the method requires.
+type AuthzLevel uint8
+
+const (
+	// AuthzLevelNone is a caller whose kernel identity could not be established.
+	AuthzLevelNone AuthzLevel = iota
+
+	// AuthzLevelIdentified is any caller the kernel could verify.
+	AuthzLevelIdentified
+
+	// AuthzLevelProfileOwner is a caller being the owner of the current targeted
+	// profile
+	AuthzLevelProfileOwner
+
+	// AuthzLevelSessionHolder is a caller that owns the current active profile
+	// and the session is currently connected (after running UP).
+	AuthzLevelSessionHolder
+
+	// AuthzLevelPrivileged is root, an elevated administrator or the daemon's
+	// own identity (if running as less privileges than root).
+	AuthzLevelPrivileged
+)
+
+// Strint() resolves a AuthzLevel to a human readable debug string.
+func (l AuthzLevel) String() string {
+	switch l {
+	case AuthzLevelIdentified:
+		return "identified"
+	case AuthzLevelProfileOwner:
+		return "profile owner"
+	case AuthzLevelSessionHolder:
+		return "session holder"
+	case AuthzLevelPrivileged:
+		return "privileged"
+	default:
+		return "unidentified"
+	}
+}
+
+func resolveLevel(id Identity, target string, st DaemonState) AuthzLevel {
+	if !id.Known() {
+		return AuthzLevelNone
+	}
+	if IsPrivilegedCaller(id) {
+		return AuthzLevelPrivileged
+	}
+	if !st.OwnsProfile(id, target) {
+		return AuthzLevelIdentified
+	}
+	if holder, running := st.SessionHolder(); !running || holder.Matches(id) {
+		return AuthzLevelSessionHolder
+	}
+	return AuthzLevelProfileOwner
+}

client/internal/ipcauth/identity_known_test.go

@@ -5,8 +5,6 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/status"
 )
 
 // The zero Identity carries uid 0, so every predicate that reads UID has to
@@ -55,65 +53,6 @@ func TestKnownForTestMarksIdentity(t *testing.T) {
 	assert.Equal(t, uint32(1000), id.UID, "KnownForTest must not alter the identity")
 }
 
-type stubState struct {
-	holder Principal
-	held   bool
-}
-
-func (s stubState) SessionHolder() (Principal, bool) { return s.holder, s.held }
-
-func uidHolder(uid uint32) Principal {
-	p, ok := ParsePrincipal(UIDPrincipal(uid))
-	if !ok {
-		panic("bad uid principal")
-	}
-	return p
-}
-
-// The holder comes from a profile JSON, the caller from a peercred read. When
-// both were an Identity, the known marker made every such comparison false and
-// the session holder could never be recognised.
-func TestRequireSessionHolderMatchesConfigOwner(t *testing.T) {
-	asDaemon(t, KnownForTest(Identity{UID: 0}))
-
-	caller := KnownForTest(Identity{UID: 1000, GID: 1000})
-	assert.NoError(t, RequireSessionHolder(caller, stubState{holder: uidHolder(1000), held: true}))
-}
-
-func TestRequireSessionHolderRejectsAnotherUser(t *testing.T) {
-	asDaemon(t, KnownForTest(Identity{UID: 0}))
-
-	caller := KnownForTest(Identity{UID: 1000, GID: 1000})
-	err := RequireSessionHolder(caller, stubState{holder: uidHolder(1001), held: true})
-	assert.Equal(t, codes.PermissionDenied, status.Code(err))
-}
-
-// With nobody connected there is no session to protect.
-func TestRequireSessionHolderAllowsWhenUnheld(t *testing.T) {
-	asDaemon(t, KnownForTest(Identity{UID: 0}))
-
-	caller := KnownForTest(Identity{UID: 1000, GID: 1000})
-	assert.NoError(t, RequireSessionHolder(caller, stubState{held: false}))
-}
-
-// An owner that could not be parsed leaves the zero Principal, which matches
-// nobody, so the session locks rather than opening.
-func TestRequireSessionHolderLocksOnUnparseableOwner(t *testing.T) {
-	asDaemon(t, KnownForTest(Identity{UID: 0}))
-
-	caller := KnownForTest(Identity{UID: 1000, GID: 1000})
-	err := RequireSessionHolder(caller, stubState{holder: Principal{}, held: true})
-	assert.Equal(t, codes.PermissionDenied, status.Code(err))
-}
-
-// Root takes over whoever holds the session.
-func TestRequireSessionHolderAllowsPrivilegedCaller(t *testing.T) {
-	asDaemon(t, KnownForTest(Identity{UID: 1000}))
-
-	root := KnownForTest(Identity{UID: 0})
-	assert.NoError(t, RequireSessionHolder(root, stubState{holder: uidHolder(1001), held: true}))
-}
-
 // A uid:0 owner is a config value, so it grants nothing on its own.
 func TestConfigOwnerCannotGrantPrivilege(t *testing.T) {
 	root, ok := ParsePrincipal("uid:0")

client/internal/ipcauth/methods.go

@@ -0,0 +1,118 @@
+package ipcauth
+
+const servicePath = "/daemon.DaemonService/"
+
+// Authorization is the decision the interceptor reached for one RPC. It is what
+// handlers read.
+type Authorization struct {
+	Identity Identity
+	Level    AuthzLevel
+	Target   string
+	Method   string
+}
+
+// Request is what a rule decides on: the authorization plus the state and the
+// message, which only the gate needs.
+type Request struct {
+	Authorization
+	State  DaemonState
+	Method string
+	Msg    any
+}
+
+// Rule is an additional constraint beyond the method's level. Every rule on a
+// method must pass.
+type Rule func(Request) error
+
+// The generated getters the profile RPCs expose.
+type handleTargeted interface{ GetHandle() string }
+type profileTargeted interface{ GetProfileName() string }
+
+// targetProfile returns the profile a request names, and whether it carries a
+// target field at all. Requests with no target act on the active profile.
+func targetProfile(msg any) (string, bool) {
+	switch m := msg.(type) {
+	case handleTargeted:
+		return m.GetHandle(), true
+	case profileTargeted:
+		return m.GetProfileName(), true
+	default:
+		return "", false
+	}
+}
+
+// MethodPolicy is what a method requires to be authorized and then handled.
+type MethodPolicy struct {
+	Level          AuthzLevel
+	Rules          []Rule
+	Audit          bool
+	TargetsProfile bool
+}
+
+// methodPolicies is the complete authorization surface. Every RPC on
+// DaemonService appears here exactly once.
+var methodPolicies = map[string]MethodPolicy{
+	// Any identified caller.
+	servicePath + "Status":           {Level: AuthzLevelIdentified, Rules: []Rule{RequireHolderForFullStatus}},
+	servicePath + "AddProfile":       {Level: AuthzLevelIdentified, Audit: true},
+	servicePath + "GetActiveProfile": {Level: AuthzLevelIdentified},
+	servicePath + "GetFeatures":      {Level: AuthzLevelIdentified},
+	servicePath + "WailsUIReady":     {Level: AuthzLevelIdentified},
+
+	// Pending flows: bound to the principal that started them, at any level.
+	servicePath + "WaitSSOLogin":          {Level: AuthzLevelIdentified, Rules: []Rule{RequireFlowInitiator}, Audit: true},
+	servicePath + "WaitJWTToken":          {Level: AuthzLevelIdentified, Rules: []Rule{RequireFlowInitiator}, Audit: true},
+	servicePath + "WaitExtendAuthSession": {Level: AuthzLevelIdentified, Rules: []Rule{RequireFlowInitiator}},
+
+	// Owner of the profile the request names.
+	servicePath + "GetConfig":     {Level: AuthzLevelProfileOwner, TargetsProfile: true, Audit: true},
+	servicePath + "SetConfig":     {Level: AuthzLevelProfileOwner, TargetsProfile: true, Audit: true},
+	servicePath + "Login":         {Level: AuthzLevelSessionHolder, TargetsProfile: true, Audit: true},
+	servicePath + "Logout":        {Level: AuthzLevelProfileOwner, TargetsProfile: true, Audit: true},
+	servicePath + "RenameProfile": {Level: AuthzLevelProfileOwner, TargetsProfile: true},
+	servicePath + "RemoveProfile": {Level: AuthzLevelProfileOwner, TargetsProfile: true, Audit: true},
+	servicePath + "SwitchProfile": {Level: AuthzLevelSessionHolder, TargetsProfile: true, Audit: true},
+
+	// Owner of some profile
+	servicePath + "ListProfiles":       {Level: AuthzLevelProfileOwner},
+	servicePath + "GetLogLevel":        {Level: AuthzLevelProfileOwner},
+	servicePath + "ListStates":         {Level: AuthzLevelProfileOwner},
+	servicePath + "GetInstallerResult": {Level: AuthzLevelProfileOwner},
+
+	// Session holder: the live engine and everything daemon-wide.
+	servicePath + "Up":                         {Level: AuthzLevelSessionHolder, TargetsProfile: true, Audit: true},
+	servicePath + "Down":                       {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "SubscribeStatus":            {Level: AuthzLevelSessionHolder},
+	servicePath + "SubscribeEvents":            {Level: AuthzLevelSessionHolder},
+	servicePath + "GetEvents":                  {Level: AuthzLevelSessionHolder},
+	servicePath + "ListNetworks":               {Level: AuthzLevelSessionHolder},
+	servicePath + "SelectNetworks":             {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "DeselectNetworks":           {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "ForwardingRules":            {Level: AuthzLevelSessionHolder},
+	servicePath + "ExposeService":              {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "GetPeerSSHHostKey":          {Level: AuthzLevelSessionHolder},
+	servicePath + "RequestJWTAuth":             {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "RequestExtendAuthSession":   {Level: AuthzLevelSessionHolder},
+	servicePath + "DismissSessionWarning":      {Level: AuthzLevelSessionHolder},
+	servicePath + "DebugBundle":                {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "SetLogLevel":                {Level: AuthzLevelSessionHolder},
+	servicePath + "SetSyncResponsePersistence": {Level: AuthzLevelSessionHolder},
+	servicePath + "StartCapture":               {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "StartBundleCapture":         {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "StopBundleCapture":          {Level: AuthzLevelSessionHolder},
+	servicePath + "StartCPUProfile":            {Level: AuthzLevelSessionHolder},
+	servicePath + "StopCPUProfile":             {Level: AuthzLevelSessionHolder},
+	servicePath + "CleanState":                 {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "DeleteState":                {Level: AuthzLevelSessionHolder, Audit: true},
+	servicePath + "TracePacket":                {Level: AuthzLevelSessionHolder},
+	servicePath + "RegisterUILog":              {Level: AuthzLevelSessionHolder},
+	servicePath + "TriggerUpdate":              {Level: AuthzLevelSessionHolder, Audit: true},
+}
+
+func methodPolicyFor(method string) MethodPolicy {
+	if p, ok := methodPolicies[method]; ok {
+		return p
+	}
+	// TODO: reconsider falling back to Privileged rather than direct DENY.
+	return MethodPolicy{Level: AuthzLevelPrivileged, Audit: true}
+}

client/internal/ipcauth/policy.go

@@ -1,93 +0,0 @@
-package ipcauth
-
-import (
-	"context"
-	"sync"
-
-	log "github.com/sirupsen/logrus"
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/status"
-)
-
-type DaemonState interface {
-	// SessionHolder returns the principal entitled to the live connection and
-	// whether one is held. A held session whose owner cannot be parsed returns
-	// the zero Principal with true, which matches nobody, so a corrupt owner
-	// field locks the session instead of opening it.
-	SessionHolder() (Principal, bool)
-}
-
-type Rule func(id Identity, st DaemonState) error
-
-type RuleGate struct {
-	mu    sync.Mutex
-	rules []Rule
-	st    DaemonState
-}
-
-func NewRuleGate() *RuleGate {
-	return &RuleGate{}
-}
-
-func (g *RuleGate) SetState(st DaemonState) {
-	g.mu.Lock()
-	defer g.mu.Unlock()
-	g.st = st
-}
-
-func (g *RuleGate) SetRule(r Rule) {
-	g.mu.Lock()
-	defer g.mu.Unlock()
-	g.rules = append(g.rules, r)
-}
-
-func (g *RuleGate) state() DaemonState {
-	g.mu.Lock()
-	defer g.mu.Unlock()
-	return g.st
-}
-
-// RequireSessionHolder allows the caller to act on the live connection. With no
-// session held there is nothing to protect, and root can always take over.
-func RequireSessionHolder(id Identity, st DaemonState) error {
-	holder, running := st.SessionHolder()
-	if !running || IsPrivilegedCaller(id) || holder.Matches(id) {
-		return nil
-	}
-	log.Debugf("caller %v is not the session holder %v", id, holder)
-	return status.Errorf(codes.PermissionDenied, "session is held by another user (%v)", holder)
-}
-
-func (g *RuleGate) StreamPolicyInterceptor() grpc.StreamServerInterceptor {
-	return func(srv any, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
-		if authErr := g.authorize(ss.Context()); authErr != nil {
-			return authErr
-		}
-		return handler(ss.Context(), ss)
-	}
-}
-
-func (g *RuleGate) UnaryPolicyInterceptor() grpc.UnaryServerInterceptor {
-	return func(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp any, err error) {
-		if authErr := g.authorize(ctx); authErr != nil {
-			return nil, authErr
-		}
-		return handler(ctx, req)
-	}
-}
-
-func (g *RuleGate) authorize(ctx context.Context) error {
-	id, ok := CallerIdentity(ctx)
-	if !ok {
-		return status.Error(codes.PermissionDenied, "caller cannot be verified")
-	}
-	state := g.state()
-	for _, rule := range g.rules {
-		ruleErr := rule(id, state)
-		if ruleErr != nil {
-			return ruleErr
-		}
-	}
-	return nil
-}

client/server/server.go

@@ -2723,6 +2723,11 @@ func (s *Server) SessionHolder() (ipcauth.Principal, bool) {
 	return principal, true
 }
 
+func (s *Server) OwnsProfile(id ipcauth.Identity, handle string) bool {
+	// TODO
+	return false
+}
+
 func persistLoginOverrides(activeProf *profilemanager.ActiveProfileState, managementURL string, preSharedKey *string) error {
 	if preSharedKey != nil && *preSharedKey == "" {
 		preSharedKey = nil