headscale/preauth_keys.go
2021-10-13 23:23:07 +02:00

128 lines
3.2 KiB
Go

package headscale
import (
"crypto/rand"
"encoding/hex"
"errors"
"time"
"gorm.io/gorm"
)
const errorAuthKeyNotFound = Error("AuthKey not found")
const errorAuthKeyExpired = Error("AuthKey expired")
const errSingleUseAuthKeyHasBeenUsed = Error("AuthKey has already been used")
// PreAuthKey describes a pre-authorization key usable in a particular namespace
type PreAuthKey struct {
ID uint64 `gorm:"primary_key"`
Key string
NamespaceID uint
Namespace Namespace
Reusable bool
Ephemeral bool `gorm:"default:false"`
CreatedAt *time.Time
Expiration *time.Time
}
// CreatePreAuthKey creates a new PreAuthKey in a namespace, and returns it
func (h *Headscale) CreatePreAuthKey(namespaceName string, reusable bool, ephemeral bool, expiration *time.Time) (*PreAuthKey, error) {
n, err := h.GetNamespace(namespaceName)
if err != nil {
return nil, err
}
now := time.Now().UTC()
kstr, err := h.generateKey()
if err != nil {
return nil, err
}
k := PreAuthKey{
Key: kstr,
NamespaceID: n.ID,
Namespace: *n,
Reusable: reusable,
Ephemeral: ephemeral,
CreatedAt: &now,
Expiration: expiration,
}
h.db.Save(&k)
return &k, nil
}
// GetPreAuthKeys returns the list of PreAuthKeys for a namespace
func (h *Headscale) GetPreAuthKeys(namespaceName string) (*[]PreAuthKey, error) {
n, err := h.GetNamespace(namespaceName)
if err != nil {
return nil, err
}
keys := []PreAuthKey{}
if err := h.db.Preload("Namespace").Where(&PreAuthKey{NamespaceID: n.ID}).Find(&keys).Error; err != nil {
return nil, err
}
return &keys, nil
}
// GetPreAuthKey returns a PreAuthKey for a given key
func (h *Headscale) GetPreAuthKey(namespace string, key string) (*PreAuthKey, error) {
pak, err := h.checkKeyValidity(key)
if err != nil {
return nil, err
}
if pak.Namespace.Name != namespace {
return nil, errors.New("Namespace mismatch")
}
return pak, nil
}
// MarkExpirePreAuthKey marks a PreAuthKey as expired
func (h *Headscale) MarkExpirePreAuthKey(k *PreAuthKey) error {
if err := h.db.Model(&k).Update("Expiration", time.Now()).Error; err != nil {
return err
}
return nil
}
// checkKeyValidity does the heavy lifting for validation of the PreAuthKey coming from a node
// If returns no error and a PreAuthKey, it can be used
func (h *Headscale) checkKeyValidity(k string) (*PreAuthKey, error) {
pak := PreAuthKey{}
if result := h.db.Preload("Namespace").First(&pak, "key = ?", k); errors.Is(result.Error, gorm.ErrRecordNotFound) {
return nil, errorAuthKeyNotFound
}
if pak.Expiration != nil && pak.Expiration.Before(time.Now()) {
return nil, errorAuthKeyExpired
}
if pak.Reusable || pak.Ephemeral { // we don't need to check if has been used before
return &pak, nil
}
machines := []Machine{}
if err := h.db.Preload("AuthKey").Where(&Machine{AuthKeyID: uint(pak.ID)}).Find(&machines).Error; err != nil {
return nil, err
}
if len(machines) != 0 {
return nil, errSingleUseAuthKeyHasBeenUsed
}
// missing here validation on current usage
return &pak, nil
}
func (h *Headscale) generateKey() (string, error) {
size := 24
bytes := make([]byte, size)
if _, err := rand.Read(bytes); err != nil {
return "", err
}
return hex.EncodeToString(bytes), nil
}