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Merge pull request #5237 from hashicorp/term-grpc-stream-on-token-failure

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Check ACLs more often for xDS endpoints.
This commit is contained in:
R.B. Boyer 2019-01-29 14:52:26 -06:00 committed by GitHub
parent 7b62d7192b 6d76b137ba
commit c11c0ea924
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 297 additions and 33 deletions
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2
agent/agent.go
View file

@ -522,6 +522,8 @@ func (a *Agent) listenAndServeGRPC() error {
Authz: a,
ResolveToken: a.resolveToken,
}
a.xdsServer.Initialize()
var err error
a.grpcServer, err = a.xdsServer.GRPCServer(a.config.CertFile, a.config.KeyFile)
if err != nil {

83
agent/xds/server.go
View file

@ -6,6 +6,7 @@ import (
"fmt"
"log"
"sync/atomic"
"time"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
@ -56,6 +57,10 @@ const (
// LocalAgentClusterName is the name we give the local agent "cluster" in
// Envoy config.
LocalAgentClusterName = "local_agent"
// DefaultAuthCheckFrequency is the default value for
// Server.AuthCheckFrequency to use when the zero value is provided.
DefaultAuthCheckFrequency = 5 * time.Minute
)
// ACLResolverFunc is a shim to resolve ACLs. Since ACL enforcement is so far
@ -90,6 +95,18 @@ type Server struct {
CfgMgr ConfigManager
Authz ConnectAuthz
ResolveToken ACLResolverFunc
// AuthCheckFrequency is how often we should re-check the credentials used
// during a long-lived gRPC Stream after it has been initially established.
// This is only used during idle periods of stream interactions (i.e. when
// there has been no recent DiscoveryRequest).
AuthCheckFrequency time.Duration
}
// Initialize will finish configuring the Server for first use.
func (s *Server) Initialize() {
if s.AuthCheckFrequency == 0 {
s.AuthCheckFrequency = DefaultAuthCheckFrequency
}
}
// StreamAggregatedResources implements
@ -126,7 +143,7 @@ func (s *Server) StreamAggregatedResources(stream ADSStream) error {
const (
stateInit int = iota
statePendingAuth
statePendingInitialConfig
stateRunning
)
@ -176,8 +193,44 @@ func (s *Server) process(stream ADSStream, reqCh <-chan *envoy.DiscoveryRequest)
},
}
var authTimer <-chan time.Time
extendAuthTimer := func() {
authTimer = time.After(s.AuthCheckFrequency)
}
checkStreamACLs := func(cfgSnap *proxycfg.ConfigSnapshot) error {
if cfgSnap == nil {
return status.Errorf(codes.Unauthenticated, "unauthenticated: no config snapshot")
}
token := tokenFromStream(stream)
rule, err := s.ResolveToken(token)
if acl.IsErrNotFound(err) {
return status.Errorf(codes.Unauthenticated, "unauthenticated: %v", err)
} else if acl.IsErrPermissionDenied(err) {
return status.Errorf(codes.PermissionDenied, "permission denied: %v", err)
} else if err != nil {
return err
}
if rule != nil && !rule.ServiceWrite(cfgSnap.Proxy.DestinationServiceName, nil) {
return status.Errorf(codes.PermissionDenied, "permission denied")
}
// Authed OK!
return nil
}
for {
select {
case <-authTimer:
// It's been too long since a Discovery{Request,Response} so recheck ACLs.
if err := checkStreamACLs(cfgSnap); err != nil {
return err
}
extendAuthTimer()
case req, ok = <-reqCh:
if !ok {
// reqCh is closed when stream.Recv errors which is how we detect client
@ -218,27 +271,27 @@ func (s *Server) process(stream ADSStream, reqCh <-chan *envoy.DiscoveryRequest)
defer watchCancel()
// Now wait for the config so we can check ACL
state = statePendingAuth
case statePendingAuth:
state = statePendingInitialConfig
case statePendingInitialConfig:
if cfgSnap == nil {
// Nothing we can do until we get the initial config
continue
}
// Got config, try to authenticate
token := tokenFromStream(stream)
rule, err := s.ResolveToken(token)
if err != nil {
return err
}
if rule != nil && !rule.ServiceWrite(cfgSnap.Proxy.DestinationServiceName, nil) {
return status.Errorf(codes.PermissionDenied, "permission denied")
}
// Authed OK!
// Got config, try to authenticate next.
state = stateRunning
// Lets actually process the config we just got or we'll mis responding
fallthrough
case stateRunning:
// Check ACLs on every Discovery{Request,Response}.
if err := checkStreamACLs(cfgSnap); err != nil {
return err
}
// For the first time through the state machine, this is when the
// timer is first started.
extendAuthTimer()
// See if any handlers need to have the current (possibly new) config
// sent. Note the order here is actually significant so we can't just
// range the map which has no determined order. It's important because:
@ -364,12 +417,12 @@ func (s *Server) Check(ctx context.Context, r *envoyauthz.CheckRequest) (*envoya
if err != nil {
// Treat this as an auth error since Envoy has sent something it considers
// valid, it's just not an identity we trust.
return deniedResponse("Destination Principal is not a valid Connect identitiy")
return deniedResponse("Destination Principal is not a valid Connect identity")
}
destID, ok := dest.(*connect.SpiffeIDService)
if !ok {
return deniedResponse("Destination Principal is not a valid Service identitiy")
return deniedResponse("Destination Principal is not a valid Service identity")
}
// For now we don't validate the trust domain of the _destination_ at all -

245
agent/xds/server_test.go
View file

@ -9,6 +9,7 @@ import (
"os"
"strings"
"sync"
"sync/atomic"
"testing"
"text/template"
"time"
@ -82,7 +83,7 @@ func (m *testManager) Watch(proxyID string) (<-chan *proxycfg.ConfigSnapshot, pr
// AssertWatchCancelled checks that the most recent call to a Watch cancel func
// was from the specified proxyID and that one is made in a short time. This
// probably won't work if you are running multiple Watches in parallel on
// multiple proxyIDS due to timing/ordering issues but I dont think we need to
// multiple proxyIDS due to timing/ordering issues but I don't think we need to
// do that.
func (m *testManager) AssertWatchCancelled(t *testing.T, proxyID string) {
t.Helper()
@ -115,7 +116,13 @@ func TestServer_StreamAggregatedResources_BasicProtocol(t *testing.T) {
envoy := NewTestEnvoy(t, "web-sidecar-proxy", "")
defer envoy.Close()
s := Server{logger, mgr, mgr, aclResolve}
s := Server{
Logger: logger,
CfgMgr: mgr,
Authz: mgr,
ResolveToken: aclResolve,
}
s.Initialize()
go func() {
err := s.StreamAggregatedResources(envoy.stream)
@ -162,11 +169,11 @@ func TestServer_StreamAggregatedResources_BasicProtocol(t *testing.T) {
// And should get a response immediately.
assertResponseSent(t, envoy.stream.sendCh, expectListenerJSON(t, snap, "", 1, 3))
// Now send Route request along with next listner one
// Now send Route request along with next listener one
envoy.SendReq(t, RouteType, 0, 0)
envoy.SendReq(t, ListenerType, 1, 3)
// We don't serve routes yet so this shoould block with no response
// We don't serve routes yet so this should block with no response
assertChanBlocked(t, envoy.stream.sendCh)
// WOOP! Envoy now has full connect config. Lets verify that if we update it,
@ -179,7 +186,7 @@ func TestServer_StreamAggregatedResources_BasicProtocol(t *testing.T) {
mgr.DeliverConfig(t, "web-sidecar-proxy", snap)
// All 3 response that have something to return should return with new version
// note that the ordering is not determinisic in general. Trying to make this
// note that the ordering is not deterministic in general. Trying to make this
// test order-agnostic though is a massive pain since we are comparing
// non-identical JSON strings (so can simply sort by anything) and because we
// don't know the order the nonces will be assigned. For now we rely and
@ -189,21 +196,21 @@ func TestServer_StreamAggregatedResources_BasicProtocol(t *testing.T) {
assertResponseSent(t, envoy.stream.sendCh, expectEndpointsJSON(t, snap, "", 2, 5))
assertResponseSent(t, envoy.stream.sendCh, expectListenerJSON(t, snap, "", 2, 6))
// Let's pretent that Envoy doesn't like that new listener config. It will ACK
// Let's pretend that Envoy doesn't like that new listener config. It will ACK
// all the others (same version) but NACK the listener. This is the most
// subtle part of xDS and the server implementation so I'll elaborate. A full
// description of the protocol can be found at
// https://github.com/envoyproxy/data-plane-api/blob/master/XDS_PROTOCOL.md.
// Envoy delays making a followup reqeest for a type until after it has
// Envoy delays making a followup request for a type until after it has
// processed and applied the last response. The next request then will include
// the nonce in the last response which acknowledges _recieving_ and handling
// the nonce in the last response which acknowledges _receiving_ and handling
// that response. It also includes the currently applied version. If all is
// good and it successfully applies the config, then the version in the next
// response will be the same version just sent. This is considered to be an
// ACK of that version for that type. If envoy fails to apply the config for
// some reason, it will still acknowledge that it received it (still return
// the responses nonce), but will show the previous version it's still using.
// This is considered a NACK. It's impotant that the server pay attention to
// This is considered a NACK. It's important that the server pay attention to
// the _nonce_ and not the version when deciding what to send otherwise a bad
// version that can't be applied in Envoy will cause a busy loop.
//
@ -489,7 +496,7 @@ func assertChanBlocked(t *testing.T, ch chan *envoy.DiscoveryResponse) {
t.Helper()
select {
case r := <-ch:
t.Fatalf("chan should block but recieved: %v", r)
t.Fatalf("chan should block but received: %v", r)
case <-time.After(10 * time.Millisecond):
return
}
@ -501,12 +508,12 @@ func assertResponseSent(t *testing.T, ch chan *envoy.DiscoveryResponse, wantJSON
case r := <-ch:
assertResponse(t, r, wantJSON)
case <-time.After(50 * time.Millisecond):
t.Fatalf("no response recieved after 50ms")
t.Fatalf("no response received after 50ms")
}
}
// assertResponse is a helper to test a envoy.DiscoveryResponse matches the
// JSON representaion we expect. We use JSON because the responses use protobuf
// JSON representation we expect. We use JSON because the responses use protobuf
// Any type which includes binary protobuf encoding and would make creating
// expected structs require the same code that is under test!
func assertResponse(t *testing.T, r *envoy.DiscoveryResponse, wantJSON string) {
@ -519,7 +526,7 @@ func assertResponse(t *testing.T, r *envoy.DiscoveryResponse, wantJSON string) {
require.JSONEqf(t, wantJSON, gotJSON, "got:\n%s", gotJSON)
}
func TestServer_StreamAggregatedResources_ACLEnforcment(t *testing.T) {
func TestServer_StreamAggregatedResources_ACLEnforcement(t *testing.T) {
tests := []struct {
name string
@ -529,7 +536,7 @@ func TestServer_StreamAggregatedResources_ACLEnforcment(t *testing.T) {
wantDenied bool
}{
// Note that although we've stubbed actual ACL checks in the testManager
// ConnectAuthorize mock, by asserting against specifc reason strings here
// ConnectAuthorize mock, by asserting against specific reason strings here
// even in the happy case which can't match the default one returned by the
// mock we are implicitly validating that the implementation used the
// correct token from the context.
@ -589,7 +596,13 @@ func TestServer_StreamAggregatedResources_ACLEnforcment(t *testing.T) {
envoy := NewTestEnvoy(t, "web-sidecar-proxy", tt.token)
defer envoy.Close()
s := Server{logger, mgr, mgr, aclResolve}
s := Server{
Logger: logger,
CfgMgr: mgr,
Authz: mgr,
ResolveToken: aclResolve,
}
s.Initialize()
errCh := make(chan error, 1)
go func() {
@ -632,6 +645,196 @@ func TestServer_StreamAggregatedResources_ACLEnforcment(t *testing.T) {
}
}
func TestServer_StreamAggregatedResources_ACLTokenDeleted_StreamTerminatedDuringDiscoveryRequest(t *testing.T) {
aclRules := `service "web" { policy = "write" }`
token := "service-write-on-web"
policy, err := acl.NewPolicyFromSource("", 0, aclRules, acl.SyntaxLegacy, nil)
require.NoError(t, err)
var validToken atomic.Value
validToken.Store(token)
logger := log.New(os.Stderr, "", log.LstdFlags)
mgr := newTestManager(t)
aclResolve := func(id string) (acl.Authorizer, error) {
if token := validToken.Load(); token == nil || id != token.(string) {
return nil, acl.ErrNotFound
}
return acl.NewPolicyAuthorizer(acl.RootAuthorizer("deny"), []*acl.Policy{policy}, nil)
}
envoy := NewTestEnvoy(t, "web-sidecar-proxy", token)
defer envoy.Close()
s := Server{
Logger: logger,
CfgMgr: mgr,
Authz: mgr,
ResolveToken: aclResolve,
AuthCheckFrequency: 1 * time.Hour, // make sure this doesn't kick in
}
s.Initialize()
errCh := make(chan error, 1)
go func() {
errCh <- s.StreamAggregatedResources(envoy.stream)
}()
getError := func() (gotErr error, ok bool) {
select {
case err := <-errCh:
return err, true
default:
return nil, false
}
}
// Register the proxy to create state needed to Watch() on
mgr.RegisterProxy(t, "web-sidecar-proxy")
// Send initial cluster discover (OK)
envoy.SendReq(t, ClusterType, 0, 0)
{
err, ok := getError()
require.NoError(t, err)
require.False(t, ok)
}
// Check no response sent yet
assertChanBlocked(t, envoy.stream.sendCh)
{
err, ok := getError()
require.NoError(t, err)
require.False(t, ok)
}
// Deliver a new snapshot
snap := proxycfg.TestConfigSnapshot(t)
mgr.DeliverConfig(t, "web-sidecar-proxy", snap)
assertResponseSent(t, envoy.stream.sendCh, expectClustersJSON(t, snap, token, 1, 1))
// Now nuke the ACL token.
validToken.Store("")
// It also (in parallel) issues the next cluster request (which acts as an ACK
// of the version we sent)
envoy.SendReq(t, ClusterType, 1, 1)
select {
case err := <-errCh:
require.Error(t, err)
gerr, ok := status.FromError(err)
require.Truef(t, ok, "not a grpc status error: type='%T' value=%v", err, err)
require.Equal(t, codes.Unauthenticated, gerr.Code())
require.Equal(t, "unauthenticated: ACL not found", gerr.Message())
mgr.AssertWatchCancelled(t, "web-sidecar-proxy")
case <-time.After(50 * time.Millisecond):
t.Fatalf("timed out waiting for handler to finish")
}
}
func TestServer_StreamAggregatedResources_ACLTokenDeleted_StreamTerminatedInBackground(t *testing.T) {
aclRules := `service "web" { policy = "write" }`
token := "service-write-on-web"
policy, err := acl.NewPolicyFromSource("", 0, aclRules, acl.SyntaxLegacy, nil)
require.NoError(t, err)
var validToken atomic.Value
validToken.Store(token)
logger := log.New(os.Stderr, "", log.LstdFlags)
mgr := newTestManager(t)
aclResolve := func(id string) (acl.Authorizer, error) {
if token := validToken.Load(); token == nil || id != token.(string) {
return nil, acl.ErrNotFound
}
return acl.NewPolicyAuthorizer(acl.RootAuthorizer("deny"), []*acl.Policy{policy}, nil)
}
envoy := NewTestEnvoy(t, "web-sidecar-proxy", token)
defer envoy.Close()
s := Server{
Logger: logger,
CfgMgr: mgr,
Authz: mgr,
ResolveToken: aclResolve,
AuthCheckFrequency: 100 * time.Millisecond, // Make this short.
}
s.Initialize()
errCh := make(chan error, 1)
go func() {
errCh <- s.StreamAggregatedResources(envoy.stream)
}()
getError := func() (gotErr error, ok bool) {
select {
case err := <-errCh:
return err, true
default:
return nil, false
}
}
// Register the proxy to create state needed to Watch() on
mgr.RegisterProxy(t, "web-sidecar-proxy")
// Send initial cluster discover (OK)
envoy.SendReq(t, ClusterType, 0, 0)
{
err, ok := getError()
require.NoError(t, err)
require.False(t, ok)
}
// Check no response sent yet
assertChanBlocked(t, envoy.stream.sendCh)
{
err, ok := getError()
require.NoError(t, err)
require.False(t, ok)
}
// Deliver a new snapshot
snap := proxycfg.TestConfigSnapshot(t)
mgr.DeliverConfig(t, "web-sidecar-proxy", snap)
assertResponseSent(t, envoy.stream.sendCh, expectClustersJSON(t, snap, token, 1, 1))
// It also (in parallel) issues the next cluster request (which acts as an ACK
// of the version we sent)
envoy.SendReq(t, ClusterType, 1, 1)
// Check no response sent yet
assertChanBlocked(t, envoy.stream.sendCh)
{
err, ok := getError()
require.NoError(t, err)
require.False(t, ok)
}
// Now nuke the ACL token while there's no activity.
validToken.Store("")
select {
case err := <-errCh:
require.Error(t, err)
gerr, ok := status.FromError(err)
require.Truef(t, ok, "not a grpc status error: type='%T' value=%v", err, err)
require.Equal(t, codes.Unauthenticated, gerr.Code())
require.Equal(t, "unauthenticated: ACL not found", gerr.Message())
mgr.AssertWatchCancelled(t, "web-sidecar-proxy")
case <-time.After(200 * time.Millisecond):
t.Fatalf("timed out waiting for handler to finish")
}
}
// This tests the ext_authz service method that implements connect authz.
func TestServer_Check(t *testing.T) {
@ -685,7 +888,7 @@ func TestServer_Check(t *testing.T) {
destPrincipal: "not-a-spiffe-id",
// Should never make it to authz call.
wantDenied: true,
wantReason: "Destination Principal is not a valid Connect identitiy",
wantReason: "Destination Principal is not a valid Connect identity",
},
{
name: "dest not a service URI",
@ -693,7 +896,7 @@ func TestServer_Check(t *testing.T) {
destPrincipal: "spiffe://trust-domain.consul",
// Should never make it to authz call.
wantDenied: true,
wantReason: "Destination Principal is not a valid Service identitiy",
wantReason: "Destination Principal is not a valid Service identity",
},
{
name: "ACL not got permission for authz call",
@ -729,7 +932,13 @@ func TestServer_Check(t *testing.T) {
envoy := NewTestEnvoy(t, "web-sidecar-proxy", token)
defer envoy.Close()
s := Server{logger, mgr, mgr, aclResolve}
s := Server{
Logger: logger,
CfgMgr: mgr,
Authz: mgr,
ResolveToken: aclResolve,
}
s.Initialize()
// Create a context with the correct token
ctx := metadata.NewIncomingContext(context.Background(),