container driver: copy ca and user tls registries certs

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

util/confutil/container.go

@@ -0,0 +1,144 @@
+package confutil
+
+import (
+	"io"
+	"os"
+	"path"
+
+	"github.com/pelletier/go-toml"
+	"github.com/pkg/errors"
+)
+
+const (
+	// DefaultBuildKitStateDir and DefaultBuildKitConfigDir are the location
+	// where buildkitd inside the container stores its state. Some drivers
+	// create a Linux container, so this should match the location for Linux,
+	// as defined in: https://github.com/moby/buildkit/blob/v0.9.0/util/appdefaults/appdefaults_unix.go#L11-L15
+	DefaultBuildKitStateDir  = "/var/lib/buildkit"
+	DefaultBuildKitConfigDir = "/etc/buildkit"
+)
+
+// LoadConfigFiles creates a temp directory with BuildKit config and
+// registry certificates ready to be copied to a container.
+func LoadConfigFiles(bkconfig string) (string, error) {
+	if _, err := os.Stat(bkconfig); errors.Is(err, os.ErrNotExist) {
+		return "", errors.Wrapf(err, "buildkit configuration file not found: %s", bkconfig)
+	} else if err != nil {
+		return "", errors.Wrapf(err, "invalid buildkit configuration file: %s", bkconfig)
+	}
+
+	// Load config tree
+	btoml, err := loadConfigTree(bkconfig)
+	if err != nil {
+		return "", err
+	}
+
+	// Temp dir that will be copied to the container
+	tmpDir, err := os.MkdirTemp("", "buildkitd-config")
+	if err != nil {
+		return "", err
+	}
+
+	// Create BuildKit config folders
+	tmpBuildKitConfigDir := path.Join(tmpDir, DefaultBuildKitConfigDir)
+	tmpBuildKitCertsDir := path.Join(tmpBuildKitConfigDir, "certs")
+	if err := os.MkdirAll(tmpBuildKitCertsDir, 0700); err != nil {
+		return "", err
+	}
+
+	// Iterate through registry config to copy certs and update
+	// BuildKit config with the underlying certs' path in the container.
+	//
+	// The following BuildKit config:
+	//
+	// [registry."myregistry.io"]
+	//   ca=["/etc/config/myca.pem"]
+	//   [[registry."myregistry.io".keypair]]
+	//     key="/etc/config/key.pem"
+	//     cert="/etc/config/cert.pem"
+	//
+	// will be translated in the container as:
+	//
+	// [registry."myregistry.io"]
+	//   ca=["/etc/buildkit/certs/myregistry.io/myca.pem"]
+	//   [[registry."myregistry.io".keypair]]
+	//     key="/etc/buildkit/certs/myregistry.io/key.pem"
+	//     cert="/etc/buildkit/certs/myregistry.io/cert.pem"
+	if btoml.Has("registry") {
+		for regName := range btoml.GetArray("registry").(*toml.Tree).Values() {
+			regConf := btoml.GetPath([]string{"registry", regName}).(*toml.Tree)
+			if regConf == nil {
+				continue
+			}
+			regCertsDir := path.Join(tmpBuildKitCertsDir, regName)
+			if err := os.Mkdir(regCertsDir, 0755); err != nil {
+				return "", err
+			}
+			if regConf.Has("ca") {
+				regCAs := regConf.GetArray("ca").([]string)
+				if len(regCAs) > 0 {
+					var cas []string
+					for _, ca := range regCAs {
+						cas = append(cas, path.Join(DefaultBuildKitConfigDir, "certs", regName, path.Base(ca)))
+						if err := copyfile(ca, path.Join(regCertsDir, path.Base(ca))); err != nil {
+							return "", err
+						}
+					}
+					regConf.Set("ca", cas)
+				}
+			}
+			if regConf.Has("keypair") {
+				regKeyPairs := regConf.GetArray("keypair").([]*toml.Tree)
+				if len(regKeyPairs) == 0 {
+					continue
+				}
+				for _, kp := range regKeyPairs {
+					if kp == nil {
+						continue
+					}
+					key := kp.Get("key").(string)
+					if len(key) > 0 {
+						kp.Set("key", path.Join(DefaultBuildKitConfigDir, "certs", regName, path.Base(key)))
+						if err := copyfile(key, path.Join(regCertsDir, path.Base(key))); err != nil {
+							return "", err
+						}
+					}
+					cert := kp.Get("cert").(string)
+					if len(cert) > 0 {
+						kp.Set("cert", path.Join(DefaultBuildKitConfigDir, "certs", regName, path.Base(cert)))
+						if err := copyfile(cert, path.Join(regCertsDir, path.Base(cert))); err != nil {
+							return "", err
+						}
+					}
+				}
+			}
+		}
+	}
+
+	// Write BuildKit config
+	bkfile, err := os.OpenFile(path.Join(tmpBuildKitConfigDir, "buildkitd.toml"), os.O_CREATE|os.O_WRONLY, 0600)
+	if err != nil {
+		return "", err
+	}
+	_, err = btoml.WriteTo(bkfile)
+	if err != nil {
+		return "", err
+	}
+
+	return tmpDir, nil
+}
+
+func copyfile(src string, dst string) error {
+	sf, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer sf.Close()
+	df, err := os.OpenFile(dst, os.O_CREATE|os.O_WRONLY, 0600)
+	if err != nil {
+		return err
+	}
+	defer df.Close()
+	_, err = io.Copy(df, sf)
+	return err
+}