Check if sys view is missing in GRPC sys view (#18210)

And return an error instead of panicking.

This situation can occur if a plugin attempts to access the system
view during setup when Vault is checking the plugin metadata.

Fixes #17878.

changelog/18210.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+sdk: Don't panic if system view or storage methods called during plugin setup.
+```

sdk/plugin/grpc_storage.go

@@ -10,6 +10,8 @@ import (
 	"github.com/hashicorp/vault/sdk/plugin/pb"
 )
 
+var errMissingStorage = errors.New("missing storage implementation: this method should not be called during plugin Setup, but only during and after Initialize")
+
 func newGRPCStorageClient(conn *grpc.ClientConn) *GRPCStorageClient {
 	return &GRPCStorageClient{
 		client: pb.NewStorageClient(conn),
@@ -74,13 +76,16 @@ func (s *GRPCStorageClient) Delete(ctx context.Context, key string) error {
 	return nil
 }
 
-// StorageServer is a net/rpc compatible structure for serving
+// GRPCStorageServer is a net/rpc compatible structure for serving
 type GRPCStorageServer struct {
 	pb.UnimplementedStorageServer
 	impl logical.Storage
 }
 
 func (s *GRPCStorageServer) List(ctx context.Context, args *pb.StorageListArgs) (*pb.StorageListReply, error) {
+	if s.impl == nil {
+		return nil, errMissingStorage
+	}
 	keys, err := s.impl.List(ctx, args.Prefix)
 	return &pb.StorageListReply{
 		Keys: keys,
@@ -89,6 +94,9 @@ func (s *GRPCStorageServer) List(ctx context.Context, args *pb.StorageListArgs)
 }
 
 func (s *GRPCStorageServer) Get(ctx context.Context, args *pb.StorageGetArgs) (*pb.StorageGetReply, error) {
+	if s.impl == nil {
+		return nil, errMissingStorage
+	}
 	storageEntry, err := s.impl.Get(ctx, args.Key)
 	if storageEntry == nil {
 		return &pb.StorageGetReply{
@@ -103,6 +111,9 @@ func (s *GRPCStorageServer) Get(ctx context.Context, args *pb.StorageGetArgs) (*
 }
 
 func (s *GRPCStorageServer) Put(ctx context.Context, args *pb.StoragePutArgs) (*pb.StoragePutReply, error) {
+	if s.impl == nil {
+		return nil, errMissingStorage
+	}
 	err := s.impl.Put(ctx, pb.ProtoStorageEntryToLogicalStorageEntry(args.Entry))
 	return &pb.StoragePutReply{
 		Err: pb.ErrToString(err),
@@ -110,6 +121,9 @@ func (s *GRPCStorageServer) Put(ctx context.Context, args *pb.StoragePutArgs) (*
 }
 
 func (s *GRPCStorageServer) Delete(ctx context.Context, args *pb.StorageDeleteArgs) (*pb.StorageDeleteReply, error) {
+	if s.impl == nil {
+		return nil, errMissingStorage
+	}
 	err := s.impl.Delete(ctx, args.Key)
 	return &pb.StorageDeleteReply{
 		Err: pb.ErrToString(err),

sdk/plugin/grpc_system.go

@@ -18,6 +18,8 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+var errMissingSystemView = errors.New("missing system view implementation: this method should not be called during plugin Setup, but only during and after Initialize")
+
 func newGRPCSystemView(conn *grpc.ClientConn) *gRPCSystemViewClient {
 	return &gRPCSystemViewClient{
 		client: pb.NewSystemViewClient(conn),
@@ -193,6 +195,9 @@ type gRPCSystemViewServer struct {
 }
 
 func (s *gRPCSystemViewServer) DefaultLeaseTTL(ctx context.Context, _ *pb.Empty) (*pb.TTLReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	ttl := s.impl.DefaultLeaseTTL()
 	return &pb.TTLReply{
 		TTL: int64(ttl),
@@ -200,6 +205,9 @@ func (s *gRPCSystemViewServer) DefaultLeaseTTL(ctx context.Context, _ *pb.Empty)
 }
 
 func (s *gRPCSystemViewServer) MaxLeaseTTL(ctx context.Context, _ *pb.Empty) (*pb.TTLReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	ttl := s.impl.MaxLeaseTTL()
 	return &pb.TTLReply{
 		TTL: int64(ttl),
@@ -207,6 +215,9 @@ func (s *gRPCSystemViewServer) MaxLeaseTTL(ctx context.Context, _ *pb.Empty) (*p
 }
 
 func (s *gRPCSystemViewServer) Tainted(ctx context.Context, _ *pb.Empty) (*pb.TaintedReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	tainted := s.impl.Tainted()
 	return &pb.TaintedReply{
 		Tainted: tainted,
@@ -214,6 +225,9 @@ func (s *gRPCSystemViewServer) Tainted(ctx context.Context, _ *pb.Empty) (*pb.Ta
 }
 
 func (s *gRPCSystemViewServer) CachingDisabled(ctx context.Context, _ *pb.Empty) (*pb.CachingDisabledReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	cachingDisabled := s.impl.CachingDisabled()
 	return &pb.CachingDisabledReply{
 		Disabled: cachingDisabled,
@@ -221,6 +235,9 @@ func (s *gRPCSystemViewServer) CachingDisabled(ctx context.Context, _ *pb.Empty)
 }
 
 func (s *gRPCSystemViewServer) ReplicationState(ctx context.Context, _ *pb.Empty) (*pb.ReplicationStateReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	replicationState := s.impl.ReplicationState()
 	return &pb.ReplicationStateReply{
 		State: int32(replicationState),
@@ -228,6 +245,9 @@ func (s *gRPCSystemViewServer) ReplicationState(ctx context.Context, _ *pb.Empty
 }
 
 func (s *gRPCSystemViewServer) ResponseWrapData(ctx context.Context, args *pb.ResponseWrapDataArgs) (*pb.ResponseWrapDataReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	data := map[string]interface{}{}
 	err := json.Unmarshal([]byte(args.Data), &data)
 	if err != nil {
@@ -253,6 +273,9 @@ func (s *gRPCSystemViewServer) ResponseWrapData(ctx context.Context, args *pb.Re
 }
 
 func (s *gRPCSystemViewServer) MlockEnabled(ctx context.Context, _ *pb.Empty) (*pb.MlockEnabledReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	enabled := s.impl.MlockEnabled()
 	return &pb.MlockEnabledReply{
 		Enabled: enabled,
@@ -260,6 +283,9 @@ func (s *gRPCSystemViewServer) MlockEnabled(ctx context.Context, _ *pb.Empty) (*
 }
 
 func (s *gRPCSystemViewServer) LocalMount(ctx context.Context, _ *pb.Empty) (*pb.LocalMountReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	local := s.impl.LocalMount()
 	return &pb.LocalMountReply{
 		Local: local,
@@ -267,6 +293,9 @@ func (s *gRPCSystemViewServer) LocalMount(ctx context.Context, _ *pb.Empty) (*pb
 }
 
 func (s *gRPCSystemViewServer) EntityInfo(ctx context.Context, args *pb.EntityInfoArgs) (*pb.EntityInfoReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	entity, err := s.impl.EntityInfo(args.EntityID)
 	if err != nil {
 		return &pb.EntityInfoReply{
@@ -279,6 +308,9 @@ func (s *gRPCSystemViewServer) EntityInfo(ctx context.Context, args *pb.EntityIn
 }
 
 func (s *gRPCSystemViewServer) GroupsForEntity(ctx context.Context, args *pb.EntityInfoArgs) (*pb.GroupsForEntityReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	groups, err := s.impl.GroupsForEntity(args.EntityID)
 	if err != nil {
 		return &pb.GroupsForEntityReply{
@@ -291,6 +323,9 @@ func (s *gRPCSystemViewServer) GroupsForEntity(ctx context.Context, args *pb.Ent
 }
 
 func (s *gRPCSystemViewServer) PluginEnv(ctx context.Context, _ *pb.Empty) (*pb.PluginEnvReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	pluginEnv, err := s.impl.PluginEnv(ctx)
 	if err != nil {
 		return &pb.PluginEnvReply{
@@ -303,6 +338,9 @@ func (s *gRPCSystemViewServer) PluginEnv(ctx context.Context, _ *pb.Empty) (*pb.
 }
 
 func (s *gRPCSystemViewServer) GeneratePasswordFromPolicy(ctx context.Context, req *pb.GeneratePasswordFromPolicyRequest) (*pb.GeneratePasswordFromPolicyReply, error) {
+	if s.impl == nil {
+		return nil, errMissingSystemView
+	}
 	policyName := req.PolicyName
 	if policyName == "" {
 		return &pb.GeneratePasswordFromPolicyReply{}, status.Errorf(codes.InvalidArgument, "no password policy specified")

sdk/plugin/grpc_system_test.go

@@ -6,7 +6,7 @@ import (
 	"testing"
 	"time"
 
-	plugin "github.com/hashicorp/go-plugin"
+	"github.com/hashicorp/go-plugin"
 	"github.com/hashicorp/vault/sdk/helper/consts"
 	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/hashicorp/vault/sdk/plugin/pb"
@@ -14,6 +14,13 @@ import (
 	"google.golang.org/protobuf/proto"
 )
 
+func TestSystem_GRPC_ReturnsErrIfSystemViewNil(t *testing.T) {
+	_, err := new(gRPCSystemViewServer).ReplicationState(context.Background(), nil)
+	if err == nil {
+		t.Error("Expected error when using server with no impl")
+	}
+}
+
 func TestSystem_GRPC_GRPC_impl(t *testing.T) {
 	var _ logical.SystemView = new(gRPCSystemViewClient)
 }

sdk/plugin/storage_test.go

@@ -1,15 +1,23 @@
 package plugin
 
 import (
+	"context"
 	"testing"
 
 	"google.golang.org/grpc"
 
-	plugin "github.com/hashicorp/go-plugin"
+	"github.com/hashicorp/go-plugin"
 	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/hashicorp/vault/sdk/plugin/pb"
 )
 
+func TestStorage_GRPC_ReturnsErrIfStorageNil(t *testing.T) {
+	_, err := new(GRPCStorageServer).Get(context.Background(), nil)
+	if err == nil {
+		t.Error("Expected error when using server with no impl")
+	}
+}
+
 func TestStorage_impl(t *testing.T) {
 	var _ logical.Storage = new(GRPCStorageClient)
 }