Add a tool to extract MDM assets from a Fleet database (#20659)

tools/mdm/assets/README.md

@@ -0,0 +1,30 @@
+## MDM asset extractor
+
+The MDM Asset Extractor is a tool designed to extract all MDM assets from a
+Fleet database. The assets are extracted unencrypted; hence, the key used for
+encrypting the assets must be provided.
+
+### Usage
+
+During development, a typical usage example would be:
+
+```
+go run tools/mdm/assets/main.go -key=E6Ow1t2dbKARxEF6O9GFI3DDQRMROhI8 -dir=mdm_assets
+```
+
+Supported flags are:
+
+```
+  -db-address string
+    	Address used to connect to the MySQL instance (default "localhost:3306")
+  -db-name string
+    	Name of the database with the asset information in the MySQL instance (default "fleet")
+  -db-password string
+    	Password used to connect to the MySQL instance (default "insecure")
+  -db-user string
+    	Username used to connect to the MySQL instance (default "fleet")
+  -dir string
+    	Directory to put the exported assets
+  -key string
+    	Key used to encrypt the assets
+```

tools/mdm/assets/main.go

@@ -0,0 +1,105 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/WatchBeam/clock"
+	"github.com/fleetdm/fleet/v4/server/config"
+	"github.com/fleetdm/fleet/v4/server/datastore/mysql"
+	"github.com/fleetdm/fleet/v4/server/fleet"
+)
+
+const (
+	testUsername = "fleet"
+	testPassword = "insecure"
+	testAddress  = "localhost:3306"
+	testDatabase = "fleet"
+)
+
+func main() {
+	flagKey := flag.String("key", "", "Key used to encrypt the assets")
+	flagDir := flag.String("dir", "", "Directory to put the exported assets")
+	flagDBUser := flag.String("db-user", testUsername, "Username used to connect to the MySQL instance")
+	flagDBPass := flag.String("db-password", testPassword, "Password used to connect to the MySQL instance")
+	flagDBAddress := flag.String("db-address", testAddress, "Address used to connect to the MySQL instance")
+	flagDBName := flag.String("db-name", testDatabase, "Name of the database with the asset information in the MySQL instance")
+	flag.Parse()
+
+	if *flagKey == "" {
+		log.Fatal("-key flag is required")
+	}
+
+	if *flagDir != "" {
+		if err := os.MkdirAll(*flagDir, os.ModePerm); err != nil {
+			log.Fatal("ensuring directory: ", err)
+		}
+	}
+
+	db, err := sql.Open(
+		"mysql",
+		fmt.Sprintf("%s:%s@tcp(%s)/?multiStatements=true", testUsername, testPassword, testAddress),
+	)
+	if err != nil {
+		log.Fatal("opening MySQL connection:", err)
+	}
+	defer db.Close()
+
+	mysqlCfg := config.MysqlConfig{
+		Username: *flagDBUser,
+		Password: *flagDBPass,
+		Address:  *flagDBAddress,
+		Database: *flagDBName,
+	}
+	ds, err := mysql.New(
+		mysqlCfg,
+		clock.NewMockClock(),
+		mysql.LimitAttempts(1),
+		mysql.WithFleetConfig(&config.FleetConfig{
+			Server: config.ServerConfig{
+				PrivateKey: *flagKey,
+			},
+		}),
+	)
+	if err != nil {
+		log.Fatal("creating datastore instance:", err)
+	}
+	defer ds.Close()
+
+	ctx := context.Background()
+	assets, err := ds.GetAllMDMConfigAssetsByName(ctx, []fleet.MDMAssetName{
+		fleet.MDMAssetCACert,
+		fleet.MDMAssetCAKey,
+		fleet.MDMAssetAPNSKey,
+		fleet.MDMAssetAPNSCert,
+		fleet.MDMAssetABMCert,
+		fleet.MDMAssetABMKey,
+		fleet.MDMAssetABMToken,
+		fleet.MDMAssetSCEPChallenge,
+	})
+	if err != nil && !errors.Is(err, mysql.ErrPartialResult) {
+		log.Fatal("retrieving assets from db:", err)
+	}
+
+	for _, asset := range assets {
+		path := filepath.Join(*flagDir, string(asset.Name))
+		switch {
+		case strings.Contains(path, "_key"):
+			path = path + ".key"
+		case strings.Contains(path, "_cert"):
+			path = path + ".crt"
+		}
+		if err := os.WriteFile(path, asset.Value, 0600); err != nil {
+			log.Fatal("writing asset:", err)
+		}
+
+		log.Printf("wrote %s in %s", asset.Name, path)
+	}
+}