mirror of
https://github.com/k3s-io/k3s.git
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336 lines
12 KiB
Go
336 lines
12 KiB
Go
package cluster
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import (
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"bytes"
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"context"
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"errors"
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"os"
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"path/filepath"
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"time"
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"github.com/k3s-io/k3s/pkg/bootstrap"
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"github.com/k3s-io/k3s/pkg/clientaccess"
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"github.com/k3s-io/k3s/pkg/daemons/config"
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"github.com/k3s-io/kine/pkg/client"
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"github.com/sirupsen/logrus"
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"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
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"k8s.io/apimachinery/pkg/util/wait"
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)
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// maxBootstrapWaitAttempts is the number of iterations to wait for another node to populate an empty bootstrap key.
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// After this many attempts, the lock is deleted and the counter reset.
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const maxBootstrapWaitAttempts = 5
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// Save writes the current ControlRuntimeBootstrap data to the datastore. This contains a complete
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// snapshot of the cluster's CA certs and keys, encryption passphrases, etc - encrypted with the join token.
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// This is used when bootstrapping a cluster from a managed database or external etcd cluster.
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// This is NOT used with embedded etcd, which bootstraps over HTTP.
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func Save(ctx context.Context, config *config.Control, override bool) error {
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logrus.Info("Saving cluster bootstrap data to datastore")
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buf := &bytes.Buffer{}
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if err := bootstrap.ReadFromDisk(buf, &config.Runtime.ControlRuntimeBootstrap); err != nil {
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return err
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}
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token := config.Token
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if token == "" {
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tokenFromFile, err := readTokenFromFile(config.Runtime.ServerToken, config.Runtime.ServerCA, config.DataDir)
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if err != nil {
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return err
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}
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token = tokenFromFile
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}
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normalizedToken, err := normalizeToken(token)
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if err != nil {
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return err
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}
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data, err := encrypt(normalizedToken, buf.Bytes())
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if err != nil {
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return err
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}
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storageClient, err := client.New(config.Runtime.EtcdConfig)
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if err != nil {
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return err
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}
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defer storageClient.Close()
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currentKey, _, err := getBootstrapKeyFromStorage(ctx, storageClient, normalizedToken, token)
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if err != nil {
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return err
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}
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// If there's an empty bootstrap key, then we've locked it and can override.
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if currentKey != nil && len(currentKey.Data) == 0 {
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logrus.Info("Bootstrap key lock is held")
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override = true
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}
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if err := storageClient.Create(ctx, storageKey(normalizedToken), data); err != nil {
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if err.Error() == "key exists" {
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if override {
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bsd, err := bootstrapKeyData(ctx, storageClient)
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if err != nil {
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return err
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}
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return storageClient.Update(ctx, storageKey(normalizedToken), bsd.Modified, data)
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}
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logrus.Warn("Bootstrap key already exists")
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return nil
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} else if errors.Is(err, rpctypes.ErrGPRCNotSupportedForLearner) {
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logrus.Debug("Skipping bootstrap data save on learner")
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return nil
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}
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return err
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}
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return nil
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}
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// bootstrapKeyData lists keys stored in the datastore with the prefix "/bootstrap", and
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// will return the first such key. It will return an error if not exactly one key is found.
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func bootstrapKeyData(ctx context.Context, storageClient client.Client) (*client.Value, error) {
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bootstrapList, err := storageClient.List(ctx, "/bootstrap", 0)
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if err != nil {
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return nil, err
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}
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if len(bootstrapList) == 0 {
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return nil, errors.New("no bootstrap data found")
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}
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if len(bootstrapList) > 1 {
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return nil, errors.New("found multiple bootstrap keys in storage")
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}
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return &bootstrapList[0], nil
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}
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// storageBootstrap loads data from the datastore's bootstrap key into the
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// ControlRuntimeBootstrap struct. The storage key and encryption passphrase are both derived
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// from the join token. If no bootstrap key exists, indicating that data needs to be written
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// back to the datastore, this function will set c.saveBootstrap to true and create an empty
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// bootstrap key as a lock. This function will not return successfully until either the
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// bootstrap key has been locked, or data is read into the struct.
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func (c *Cluster) storageBootstrap(ctx context.Context) error {
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if err := c.startStorage(ctx); err != nil {
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return err
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}
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storageClient, err := client.New(c.config.Runtime.EtcdConfig)
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if err != nil {
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return err
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}
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defer storageClient.Close()
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token := c.config.Token
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if token == "" {
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tokenFromFile, err := readTokenFromFile(c.config.Runtime.ServerToken, c.config.Runtime.ServerCA, c.config.DataDir)
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if err != nil {
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return err
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}
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if tokenFromFile == "" {
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// No token on disk or from CLI, but we don't know if there's data in the datastore.
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// Return here and generate new CA certs and tokens. Note that startup will fail
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// later when saving to the datastore if there's already a bootstrap key - but
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// that's AFTER generating CA certs and tokens. If the config is updated to set the
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// matching key, further startups will still be blocked pending cleanup of the
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// "newer" files as per the bootstrap reconciliation code.
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c.saveBootstrap = true
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return nil
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}
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token = tokenFromFile
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}
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normalizedToken, err := normalizeToken(token)
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if err != nil {
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return err
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}
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attempts := 0
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tokenKey := storageKey(normalizedToken)
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return wait.PollImmediateUntilWithContext(ctx, time.Second, func(ctx context.Context) (bool, error) {
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attempts++
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value, saveBootstrap, err := getBootstrapKeyFromStorage(ctx, storageClient, normalizedToken, token)
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c.saveBootstrap = saveBootstrap
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if err != nil {
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return false, err
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}
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if value == nil {
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// No bootstrap keys found in the datastore - create an empty bootstrap key as a lock to
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// ensure that no other node races us to populate it. If we fail to create the key, then
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// some other node beat us to it and we should just wait for them to finish.
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if err := storageClient.Create(ctx, tokenKey, []byte{}); err != nil {
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if err.Error() == "key exists" {
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logrus.Info("Bootstrap key already locked - waiting for data to be populated by another server")
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return false, nil
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}
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return false, err
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}
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logrus.Info("Bootstrap key locked for initial create")
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return true, nil
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}
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if len(value.Data) == 0 {
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// Empty (locked) bootstrap key found - check to see if we should continue waiting, or
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// delete it and attempt to retake the lock on the next iteration (assuming that the
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// other node failed while holding the lock).
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if attempts >= maxBootstrapWaitAttempts {
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logrus.Info("Bootstrap key lock timed out - deleting lock and retrying")
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attempts = 0
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if err := storageClient.Delete(ctx, tokenKey, value.Modified); err != nil {
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return false, err
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}
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} else {
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logrus.Infof("Bootstrap key is locked - waiting for data to be populated by another server")
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}
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return false, nil
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}
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data, err := decrypt(normalizedToken, value.Data)
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if err != nil {
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return false, err
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}
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return true, c.ReconcileBootstrapData(ctx, bytes.NewReader(data), &c.config.Runtime.ControlRuntimeBootstrap, false)
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})
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}
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// getBootstrapKeyFromStorage will list all keys that has prefix /bootstrap and will check for key that is
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// hashed with empty string and will check for any key that is hashed by different token than the one
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// passed to it, it will return error if it finds a key that is hashed with different token and will return
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// value if it finds the key hashed by passed token or empty string.
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// Upon receiving a "not supported for learner" error from etcd, this function will retry until the context is cancelled.
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func getBootstrapKeyFromStorage(ctx context.Context, storageClient client.Client, normalizedToken, oldToken string) (*client.Value, bool, error) {
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emptyStringKey := storageKey("")
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tokenKey := storageKey(normalizedToken)
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var bootstrapList []client.Value
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var err error
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if err := wait.PollImmediateUntilWithContext(ctx, 5*time.Second, func(ctx context.Context) (bool, error) {
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bootstrapList, err = storageClient.List(ctx, "/bootstrap", 0)
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if err != nil {
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if errors.Is(err, rpctypes.ErrGPRCNotSupportedForLearner) {
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return false, nil
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}
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return false, err
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}
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return true, nil
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}); err != nil {
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return nil, false, err
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}
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if len(bootstrapList) == 0 {
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return nil, true, nil
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}
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if len(bootstrapList) > 1 {
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logrus.Warn("found multiple bootstrap keys in storage")
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}
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// check for empty string key and for old token format with k10 prefix
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if err := migrateOldTokens(ctx, bootstrapList, storageClient, emptyStringKey, tokenKey, normalizedToken, oldToken); err != nil {
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return nil, false, err
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}
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// getting the list of bootstrap again after migrating the empty key
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bootstrapList, err = storageClient.List(ctx, "/bootstrap", 0)
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if err != nil {
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return nil, false, err
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}
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for _, bootstrapKV := range bootstrapList {
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// ensure bootstrap is stored in the current token's key
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if string(bootstrapKV.Key) == tokenKey {
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return &bootstrapKV, false, nil
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}
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}
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return nil, false, errors.New("bootstrap data already found and encrypted with different token")
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}
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// readTokenFromFile will attempt to get the token from <data-dir>/token if it the file not found
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// in case of fresh installation it will try to use the runtime serverToken saved in memory
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// after stripping it from any additional information like the username or cahash, if the file
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// found then it will still strip the token from any additional info
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func readTokenFromFile(serverToken, certs, dataDir string) (string, error) {
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tokenFile := filepath.Join(dataDir, "token")
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b, err := os.ReadFile(tokenFile)
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if err != nil {
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if os.IsNotExist(err) {
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token, err := clientaccess.FormatToken(serverToken, certs)
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if err != nil {
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return token, err
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}
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return token, nil
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}
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return "", err
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}
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// strip the token from any new line if its read from file
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return string(bytes.TrimRight(b, "\n")), nil
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}
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// normalizeToken will normalize the token read from file or passed as a cli flag
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func normalizeToken(token string) (string, error) {
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_, password, ok := clientaccess.ParseUsernamePassword(token)
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if !ok {
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return password, errors.New("failed to normalize server token; must be in format K10<CA-HASH>::<USERNAME>:<PASSWORD> or <PASSWORD>")
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}
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return password, nil
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}
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// migrateOldTokens will list all keys that has prefix /bootstrap and will check for key that is
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// hashed with empty string and keys that is hashed with old token format before normalizing
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// then migrate those and resave only with the normalized token
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func migrateOldTokens(ctx context.Context, bootstrapList []client.Value, storageClient client.Client, emptyStringKey, tokenKey, token, oldToken string) error {
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oldTokenKey := storageKey(oldToken)
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for _, bootstrapKV := range bootstrapList {
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// checking for empty string bootstrap key
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if string(bootstrapKV.Key) == emptyStringKey {
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logrus.Warn("Bootstrap data encrypted with empty string, deleting and resaving with token")
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if err := doMigrateToken(ctx, storageClient, bootstrapKV, "", emptyStringKey, token, tokenKey); err != nil {
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return err
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}
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} else if string(bootstrapKV.Key) == oldTokenKey && oldTokenKey != tokenKey {
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logrus.Warn("bootstrap data encrypted with old token format string, deleting and resaving with token")
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if err := doMigrateToken(ctx, storageClient, bootstrapKV, oldToken, oldTokenKey, token, tokenKey); err != nil {
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return err
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}
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}
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}
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return nil
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}
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func doMigrateToken(ctx context.Context, storageClient client.Client, keyValue client.Value, oldToken, oldTokenKey, newToken, newTokenKey string) error {
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// make sure that the process is non-destructive by decrypting/re-encrypting/storing the data before deleting the old key
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data, err := decrypt(oldToken, keyValue.Data)
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if err != nil {
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return err
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}
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encryptedData, err := encrypt(newToken, data)
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if err != nil {
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return err
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}
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// saving the new encrypted data with the right token key
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if err := storageClient.Create(ctx, newTokenKey, encryptedData); err != nil {
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if err.Error() == "key exists" {
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logrus.Warn("bootstrap key exists")
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} else if errors.Is(err, rpctypes.ErrGPRCNotSupportedForLearner) {
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logrus.Debug("skipping bootstrap data save on learner")
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return nil
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} else {
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return err
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}
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}
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logrus.Infof("created bootstrap key %s", newTokenKey)
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// deleting the old key
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if err := storageClient.Delete(ctx, oldTokenKey, keyValue.Modified); err != nil {
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logrus.Warnf("failed to delete old bootstrap key %s", oldTokenKey)
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}
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return nil
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}
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