certificates/authority/provisioner/collection.go
2021-07-02 19:05:17 -07:00

351 lines
9.8 KiB
Go

package provisioner
import (
"crypto/sha1"
"crypto/x509"
"encoding/asn1"
"encoding/binary"
"encoding/hex"
"fmt"
"net/url"
"sort"
"strings"
"sync"
"github.com/smallstep/certificates/authority/admin"
"go.step.sm/crypto/jose"
)
// DefaultProvisionersLimit is the default limit for listing provisioners.
const DefaultProvisionersLimit = 20
// DefaultProvisionersMax is the maximum limit for listing provisioners.
const DefaultProvisionersMax = 100
type uidProvisioner struct {
provisioner Interface
uid string
}
type provisionerSlice []uidProvisioner
func (p provisionerSlice) Len() int { return len(p) }
func (p provisionerSlice) Less(i, j int) bool { return p[i].uid < p[j].uid }
func (p provisionerSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
// loadByTokenPayload is a payload used to extract the id used to load the
// provisioner.
type loadByTokenPayload struct {
jose.Claims
AuthorizedParty string `json:"azp"` // OIDC client id
TenantID string `json:"tid"` // Microsoft Azure tenant id
}
// Collection is a memory map of provisioners.
type Collection struct {
byID *sync.Map
byKey *sync.Map
byName *sync.Map
byTokenID *sync.Map
sorted provisionerSlice
audiences Audiences
}
// NewCollection initializes a collection of provisioners. The given list of
// audiences are the audiences used by the JWT provisioner.
func NewCollection(audiences Audiences) *Collection {
return &Collection{
byID: new(sync.Map),
byKey: new(sync.Map),
byName: new(sync.Map),
byTokenID: new(sync.Map),
audiences: audiences,
}
}
// Load a provisioner by the ID.
func (c *Collection) Load(id string) (Interface, bool) {
return loadProvisioner(c.byID, id)
}
// LoadByName a provisioner by name.
func (c *Collection) LoadByName(name string) (Interface, bool) {
return loadProvisioner(c.byName, name)
}
// LoadByTokenID a provisioner by identifier found in token.
// For different provisioner types this identifier may be found in in different
// attributes of the token.
func (c *Collection) LoadByTokenID(tokenProvisionerID string) (Interface, bool) {
return loadProvisioner(c.byTokenID, tokenProvisionerID)
}
// LoadByToken parses the token claims and loads the provisioner associated.
func (c *Collection) LoadByToken(token *jose.JSONWebToken, claims *jose.Claims) (Interface, bool) {
var audiences []string
// Get all audiences with the given fragment
fragment := extractFragment(claims.Audience)
if fragment == "" {
audiences = c.audiences.All()
} else {
audiences = c.audiences.WithFragment(fragment).All()
}
// match with server audiences
if matchesAudience(claims.Audience, audiences) {
// Use fragment to get provisioner name (GCP, AWS, SSHPOP)
if fragment != "" {
return c.LoadByTokenID(fragment)
}
// If matches with stored audiences it will be a JWT token (default), and
// the id would be <issuer>:<kid>.
// TODO: is this ok?
return c.LoadByTokenID(claims.Issuer + ":" + token.Headers[0].KeyID)
}
// The ID will be just the clientID stored in azp, aud or tid.
var payload loadByTokenPayload
if err := token.UnsafeClaimsWithoutVerification(&payload); err != nil {
return nil, false
}
// Kubernetes Service Account tokens.
if payload.Issuer == k8sSAIssuer {
if p, ok := c.LoadByTokenID(K8sSAID); ok {
return p, ok
}
// Kubernetes service account provisioner not found
return nil, false
}
// Audience is required for non k8sSA tokens.
if len(payload.Audience) == 0 {
return nil, false
}
// Try with azp (OIDC)
if len(payload.AuthorizedParty) > 0 {
if p, ok := c.LoadByTokenID(payload.AuthorizedParty); ok {
return p, ok
}
}
// Try with tid (Azure)
if payload.TenantID != "" {
if p, ok := c.LoadByTokenID(payload.TenantID); ok {
return p, ok
}
}
// Fallback to aud
return c.LoadByTokenID(payload.Audience[0])
}
// LoadByCertificate looks for the provisioner extension and extracts the
// proper id to load the provisioner.
func (c *Collection) LoadByCertificate(cert *x509.Certificate) (Interface, bool) {
for _, e := range cert.Extensions {
if e.Id.Equal(stepOIDProvisioner) {
var provisioner stepProvisionerASN1
if _, err := asn1.Unmarshal(e.Value, &provisioner); err != nil {
return nil, false
}
return c.LoadByName(string(provisioner.Name))
}
}
// Default to noop provisioner if an extension is not found. This allows to
// accept a renewal of a cert without the provisioner extension.
return &noop{}, true
}
// LoadEncryptedKey returns an encrypted key by indexed by KeyID. At this moment
// only JWK encrypted keys are indexed by KeyID.
func (c *Collection) LoadEncryptedKey(keyID string) (string, bool) {
p, ok := loadProvisioner(c.byKey, keyID)
if !ok {
return "", false
}
_, key, ok := p.GetEncryptedKey()
return key, ok
}
// Store adds a provisioner to the collection and enforces the uniqueness of
// provisioner IDs.
func (c *Collection) Store(p Interface) error {
// Store provisioner always in byID. ID must be unique.
if _, loaded := c.byID.LoadOrStore(p.GetID(), p); loaded {
return admin.NewError(admin.ErrorBadRequestType,
"cannot add multiple provisioners with the same id")
}
// Store provisioner always by name.
if _, loaded := c.byName.LoadOrStore(p.GetName(), p); loaded {
c.byID.Delete(p.GetID())
return admin.NewError(admin.ErrorBadRequestType,
"cannot add multiple provisioners with the same name")
}
// Store provisioner always by ID presented in token.
if _, loaded := c.byTokenID.LoadOrStore(p.GetIDForToken(), p); loaded {
c.byID.Delete(p.GetID())
c.byName.Delete(p.GetName())
return admin.NewError(admin.ErrorBadRequestType,
"cannot add multiple provisioners with the same token identifier")
}
// Store provisioner in byKey if EncryptedKey is defined.
if kid, _, ok := p.GetEncryptedKey(); ok {
c.byKey.Store(kid, p)
}
// Store sorted provisioners.
// Use the first 4 bytes (32bit) of the sum to insert the order
// Using big endian format to get the strings sorted:
// 0x00000000, 0x00000001, 0x00000002, ...
bi := make([]byte, 4)
sum := provisionerSum(p)
binary.BigEndian.PutUint32(bi, uint32(c.sorted.Len()))
sum[0], sum[1], sum[2], sum[3] = bi[0], bi[1], bi[2], bi[3]
c.sorted = append(c.sorted, uidProvisioner{
provisioner: p,
uid: hex.EncodeToString(sum),
})
sort.Sort(c.sorted)
return nil
}
// Remove deletes an provisioner from all associated collections and lists.
func (c *Collection) Remove(id string) error {
prov, ok := c.Load(id)
if !ok {
return admin.NewError(admin.ErrorNotFoundType, "provisioner %s not found", id)
}
var found bool
for i, elem := range c.sorted {
if elem.provisioner.GetID() == id {
// Remove index in sorted list
copy(c.sorted[i:], c.sorted[i+1:]) // Shift a[i+1:] left one index.
c.sorted[len(c.sorted)-1] = uidProvisioner{} // Erase last element (write zero value).
c.sorted = c.sorted[:len(c.sorted)-1] // Truncate slice.
found = true
break
}
}
if !found {
return admin.NewError(admin.ErrorNotFoundType, "provisioner %s not found in sorted list", prov.GetName())
}
c.byID.Delete(id)
c.byName.Delete(prov.GetName())
c.byTokenID.Delete(prov.GetIDForToken())
if kid, _, ok := prov.GetEncryptedKey(); ok {
c.byKey.Delete(kid)
}
return nil
}
// Update updates the given provisioner in all related lists and collections.
func (c *Collection) Update(nu Interface) error {
old, ok := c.Load(nu.GetID())
if !ok {
return admin.NewError(admin.ErrorNotFoundType, "provisioner %s not found", nu.GetID())
}
if old.GetName() != nu.GetName() {
if _, ok := c.LoadByName(nu.GetName()); ok {
return admin.NewError(admin.ErrorBadRequestType,
"provisioner with name %s already exists", nu.GetName())
}
}
if old.GetIDForToken() != nu.GetIDForToken() {
if _, ok := c.LoadByTokenID(nu.GetIDForToken()); ok {
return admin.NewError(admin.ErrorBadRequestType,
"provisioner with Token ID %s already exists", nu.GetIDForToken())
}
}
if err := c.Remove(old.GetID()); err != nil {
return err
}
return c.Store(nu)
}
// Find implements pagination on a list of sorted provisioners.
func (c *Collection) Find(cursor string, limit int) (List, string) {
switch {
case limit <= 0:
limit = DefaultProvisionersLimit
case limit > DefaultProvisionersMax:
limit = DefaultProvisionersMax
}
n := c.sorted.Len()
cursor = fmt.Sprintf("%040s", cursor)
i := sort.Search(n, func(i int) bool { return c.sorted[i].uid >= cursor })
slice := List{}
for ; i < n && len(slice) < limit; i++ {
slice = append(slice, c.sorted[i].provisioner)
}
if i < n {
return slice, strings.TrimLeft(c.sorted[i].uid, "0")
}
return slice, ""
}
func loadProvisioner(m *sync.Map, key string) (Interface, bool) {
i, ok := m.Load(key)
if !ok {
return nil, false
}
p, ok := i.(Interface)
if !ok {
return nil, false
}
return p, true
}
// provisionerSum returns the SHA1 of the provisioners ID. From this we will
// create the unique and sorted id.
func provisionerSum(p Interface) []byte {
sum := sha1.Sum([]byte(p.GetID()))
return sum[:]
}
// matchesAudience returns true if A and B share at least one element.
func matchesAudience(as, bs []string) bool {
if len(bs) == 0 || len(as) == 0 {
return false
}
for _, b := range bs {
for _, a := range as {
if b == a || stripPort(a) == stripPort(b) {
return true
}
}
}
return false
}
// stripPort attempts to strip the port from the given url. If parsing the url
// produces errors it will just return the passed argument.
func stripPort(rawurl string) string {
u, err := url.Parse(rawurl)
if err != nil {
return rawurl
}
u.Host = u.Hostname()
return u.String()
}
// extractFragment extracts the first fragment of an audience url.
func extractFragment(audience []string) string {
for _, s := range audience {
if u, err := url.Parse(s); err == nil && u.Fragment != "" {
return u.Fragment
}
}
return ""
}