certificates/authority/provisioner/collection.go
Mariano Cano f919535475 Add an extra way to distinguish Azure and Azure OIDC tokens.
We used to distinguish these tokens using the azp claim, but this
claim does not appear on new azure oidc tokens, at least on some
configurations.

This change will try to load by audience (client id) if the token
contains an email, required for OIDC.
2021-08-30 16:37:29 -07:00

360 lines
10 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
Email string `json:"email"` // OIDC email
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, Azure OIDC)
if payload.TenantID != "" {
// Try to load an OIDC provisioner first.
if payload.Email != "" {
if p, ok := c.LoadByTokenID(payload.Audience[0]); ok {
return p, ok
}
}
// Try to load an Azure provisioner.
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 ""
}