feat: enable version API in maintenance mode

Version API is only available over SideroLink connection.

This is useful to find Talos version as it got booted (e.g. to generate
proper machine configuration).

There's a security concern that version API might return sensitive
information via public API. At the same time Talos version can be
guessed by looking at the output of other APIs, e.g. resource type list
(`talosctl get rd`), which changes with every minor version.

Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>

cmd/talosctl/cmd/talos/version.go

@@ -24,6 +24,7 @@ var versionCmdFlags struct {
 	clientOnly   bool
 	shortVersion bool
 	json         bool
+	insecure     bool
 }
 
 // versionCmd represents the `talosctl version` command.
@@ -49,56 +50,65 @@ var versionCmd = &cobra.Command{
 			fmt.Println("Server:")
 		}
 
-		return WithClient(func(ctx context.Context, c *client.Client) error {
-			var remotePeer peer.Peer
+		if versionCmdFlags.insecure {
+			return WithClientMaintenance(nil, cmdVersion)
+		}
 
-			resp, err := c.Version(ctx, grpc.Peer(&remotePeer))
-			if err != nil {
-				if resp == nil {
-					return fmt.Errorf("error getting version: %s", err)
-				}
-				cli.Warning("%s", err)
-			}
+		return WithClient(cmdVersion)
+	},
+}
 
-			defaultNode := client.AddrFromPeer(&remotePeer)
+func cmdVersion(ctx context.Context, c *client.Client) error {
+	var remotePeer peer.Peer
 
-			for _, msg := range resp.Messages {
-				node := defaultNode
+	resp, err := c.Version(ctx, grpc.Peer(&remotePeer))
+	if err != nil {
+		if resp == nil {
+			return fmt.Errorf("error getting version: %s", err)
+		}
 
-				if msg.Metadata != nil {
-					node = msg.Metadata.Hostname
-				}
+		cli.Warning("%s", err)
+	}
 
-				if !versionCmdFlags.json {
-					fmt.Printf("\t%s:        %s\n", "NODE", node)
+	defaultNode := client.AddrFromPeer(&remotePeer)
 
-					version.PrintLongVersionFromExisting(msg.Version)
+	for _, msg := range resp.Messages {
+		node := defaultNode
 
-					var enabledFeatures []string
-					if msg.Features.GetRbac() {
-						enabledFeatures = append(enabledFeatures, "RBAC")
-					}
+		if msg.Metadata != nil {
+			node = msg.Metadata.Hostname
+		}
 
-					fmt.Printf("\tEnabled:     %s\n", strings.Join(enabledFeatures, ", "))
+		if !versionCmdFlags.json {
+			fmt.Printf("\t%s:        %s\n", "NODE", node)
 
-					continue
-				}
+			version.PrintLongVersionFromExisting(msg.Version)
 
-				b, err := protojson.Marshal(msg)
-				if err != nil {
-					return err
-				}
-				fmt.Printf("%s\n", b)
+			var enabledFeatures []string
+			if msg.Features.GetRbac() {
+				enabledFeatures = append(enabledFeatures, "RBAC")
 			}
 
-			return nil
-		})
-	},
+			fmt.Printf("\tEnabled:     %s\n", strings.Join(enabledFeatures, ", "))
+
+			continue
+		}
+
+		b, err := protojson.Marshal(msg)
+		if err != nil {
+			return err
+		}
+
+		fmt.Printf("%s\n", b)
+	}
+
+	return nil
 }
 
 func init() {
 	versionCmd.Flags().BoolVar(&versionCmdFlags.shortVersion, "short", false, "Print the short version")
 	versionCmd.Flags().BoolVar(&versionCmdFlags.clientOnly, "client", false, "Print client version only")
+	versionCmd.Flags().BoolVarP(&versionCmdFlags.insecure, "insecure", "i", false, "use Talos maintenance mode API")
 
 	// TODO remove when https://github.com/talos-systems/talos/issues/907 is implemented
 	versionCmd.Flags().BoolVar(&versionCmdFlags.json, "json", false, "")

internal/app/maintenance/server/server.go

@@ -8,11 +8,15 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"net"
 	"strings"
 
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/peer"
 	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/emptypb"
+	"inet.af/netaddr"
 
 	"github.com/talos-systems/talos/internal/app/machined/pkg/runtime"
 	"github.com/talos-systems/talos/internal/app/resources"
@@ -23,6 +27,8 @@ import (
 	"github.com/talos-systems/talos/pkg/machinery/api/storage"
 	"github.com/talos-systems/talos/pkg/machinery/config/configloader"
 	v1alpha1machine "github.com/talos-systems/talos/pkg/machinery/config/types/v1alpha1/machine"
+	"github.com/talos-systems/talos/pkg/machinery/resources/network"
+	"github.com/talos-systems/talos/pkg/version"
 )
 
 // Server implements machine.MachineService, network.NetworkService, and storage.StorageService.
@@ -116,3 +122,53 @@ func (s *Server) GenerateConfiguration(ctx context.Context, in *machine.Generate
 func (s *Server) GenerateClientConfiguration(ctx context.Context, in *machine.GenerateClientConfigurationRequest) (*machine.GenerateClientConfigurationResponse, error) {
 	return nil, status.Error(codes.Unimplemented, "client configuration (talosconfig) can't be generated in the maintenance mode")
 }
+
+func verifyPeer(ctx context.Context, condition func(netaddr.IP) bool) bool {
+	remotePeer, ok := peer.FromContext(ctx)
+	if !ok {
+		return false
+	}
+
+	if remotePeer.Addr.Network() != "tcp" {
+		return false
+	}
+
+	ip, _, err := net.SplitHostPort(remotePeer.Addr.String())
+	if err != nil {
+		return false
+	}
+
+	addr, err := netaddr.ParseIP(ip)
+	if err != nil {
+		return false
+	}
+
+	return condition(addr)
+}
+
+// Version implements the machine.MachineServer interface.
+func (s *Server) Version(ctx context.Context, in *emptypb.Empty) (*machine.VersionResponse, error) {
+	if !verifyPeer(ctx, func(addr netaddr.IP) bool {
+		return network.IsULA(addr, network.ULASideroLink)
+	}) {
+		return nil, status.Error(codes.Unimplemented, "Version API is not implemented in maintenance mode")
+	}
+
+	var platform *machine.PlatformInfo
+
+	if s.runtime.State().Platform() != nil {
+		platform = &machine.PlatformInfo{
+			Name: s.runtime.State().Platform().Name(),
+			Mode: s.runtime.State().Platform().Mode().String(),
+		}
+	}
+
+	return &machine.VersionResponse{
+		Messages: []*machine.Version{
+			{
+				Version:  version.NewVersion(),
+				Platform: platform,
+			},
+		},
+	}, nil
+}

website/content/v1.1/reference/cli.md

@@ -2094,9 +2094,10 @@ talosctl version [flags]
 ### Options
 
 ```
-      --client   Print client version only
-  -h, --help     help for version
-      --short    Print the short version
+      --client     Print client version only
+  -h, --help       help for version
+  -i, --insecure   use Talos maintenance mode API
+      --short      Print the short version
 ```
 
 ### Options inherited from parent commands