docker/swarmkit

package secrets

import (
    "fmt"
    "sync"

    "github.com/moby/swarmkit/v2/agent/exec"
    "github.com/moby/swarmkit/v2/api"
    "github.com/moby/swarmkit/v2/identity"
)

// secrets is a map that keeps all the currently available secrets to the agent
// mapped by secret ID.
type secrets struct {
    mu sync.RWMutex
    m  map[string]*api.Secret
}

// NewManager returns a place to store secrets.
func NewManager() exec.SecretsManager {
    return &secrets{
        m: make(map[string]*api.Secret),
    }
}

// Get returns a secret by ID.  If the secret doesn't exist, returns nil.
func (s *secrets) Get(secretID string) (*api.Secret, error) {
    s.mu.RLock()
    defer s.mu.RUnlock()
    if s, ok := s.m[secretID]; ok {
        return s, nil
    }
    return nil, fmt.Errorf("secret %s not found", secretID)
}

// Add adds one or more secrets to the secret map.
func (s *secrets) Add(secrets ...api.Secret) {
    s.mu.Lock()
    defer s.mu.Unlock()
    for _, secret := range secrets {
        s.m[secret.ID] = secret.Copy()
    }
}

// Remove removes one or more secrets by ID from the secret map.  Succeeds
// whether or not the given IDs are in the map.
func (s *secrets) Remove(secrets []string) {
    s.mu.Lock()
    defer s.mu.Unlock()
    for _, secret := range secrets {
        delete(s.m, secret)
    }
}

// Reset removes all the secrets.
func (s *secrets) Reset() {
    s.mu.Lock()
    defer s.mu.Unlock()
    s.m = make(map[string]*api.Secret)
}

// taskRestrictedSecretsProvider restricts the ids to the task.
type taskRestrictedSecretsProvider struct {
    secrets   exec.SecretGetter
    secretIDs map[string]struct{} // allow list of secret ids
    taskID    string              // ID of the task the provider restricts for
}

func (sp *taskRestrictedSecretsProvider) Get(secretID string) (*api.Secret, error) {
    if _, ok := sp.secretIDs[secretID]; !ok {
        return nil, fmt.Errorf("task not authorized to access secret %s", secretID)
    }

    // First check if the secret is available with the task specific ID, which is the concatenation
    // of the original secret ID and the task ID with a dot in between.
    // That is the case when a secret driver has returned DoNotReuse == true for a secret value.
    taskSpecificID := identity.CombineTwoIDs(secretID, sp.taskID)
    secret, err := sp.secrets.Get(taskSpecificID)
    if err != nil {
        // Otherwise, which is the default case, the secret is retrieved by its original ID.
        return sp.secrets.Get(secretID)
    }
    // For all intents and purposes, the rest of the flow should deal with the original secret ID.
    secret.ID = secretID
    return secret, err
}

// Restrict provides a getter that only allows access to the secrets
// referenced by the task.
func Restrict(secrets exec.SecretGetter, t *api.Task) exec.SecretGetter {
    sids := map[string]struct{}{}

    container := t.Spec.GetContainer()
    if container != nil {
        for _, ref := range container.Secrets {
            sids[ref.SecretID] = struct{}{}
        }
    }

    return &taskRestrictedSecretsProvider{secrets: secrets, secretIDs: sids, taskID: t.ID}
}