auth/okta: Add support for Okta number challenge (#15361)

* POC of Okta Auth Number Challenge verification

* switch from callbacks to operations, forward validate to primary

* cleanup and nonce description update

* add changelog

* error on empty nonce, no forwarding, return correct_answer instead

* properly clean up verify goroutine

* add docs on new endpoint and parameters

* change polling frequency when WAITING to 1s

Co-authored-by: Jim Kalafut <jkalafut@hashicorp.com>

builtin/credential/okta/backend.go

@@ -11,6 +11,7 @@ import (
 	"github.com/hashicorp/vault/sdk/helper/cidrutil"
 	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/okta/okta-sdk-golang/v2/okta"
+	"github.com/patrickmn/go-cache"
 )
 
 const (
@@ -34,6 +35,7 @@ func Backend() *backend {
 		PathsSpecial: &logical.Paths{
 			Unauthenticated: []string{
 				"login/*",
+				"verify/*",
 			},
 			SealWrapStorage: []string{
 				"config",
@@ -47,20 +49,23 @@ func Backend() *backend {
 			pathUsersList(&b),
 			pathGroupsList(&b),
 			pathLogin(&b),
+			pathVerify(&b),
 		},
 
 		AuthRenew:   b.pathLoginRenew,
 		BackendType: logical.TypeCredential,
 	}
+	b.verifyCache = cache.New(5*time.Minute, time.Minute)
 
 	return &b
 }
 
 type backend struct {
 	*framework.Backend
+	verifyCache *cache.Cache
 }
 
-func (b *backend) Login(ctx context.Context, req *logical.Request, username, password, totp, preferredProvider string) ([]string, *logical.Response, []string, error) {
+func (b *backend) Login(ctx context.Context, req *logical.Request, username, password, totp, nonce, preferredProvider string) ([]string, *logical.Response, []string, error) {
 	cfg, err := b.Config(ctx, req.Storage)
 	if err != nil {
 		return nil, nil, nil, err
@@ -89,11 +94,17 @@ func (b *backend) Login(ctx context.Context, req *logical.Request, username, pas
 		Id       string `json:"id"`
 		Type     string `json:"factorType"`
 		Provider string `json:"provider"`
+		Embedded struct {
+			Challenge struct {
+				CorrectAnswer *int `json:"correctAnswer"`
+			} `json:"challenge"`
+		} `json:"_embedded"`
 	}
 
 	type embeddedResult struct {
 		User    okta.User   `json:"user"`
 		Factors []mfaFactor `json:"factors"`
+		Factor  *mfaFactor  `json:"factor"`
 	}
 
 	type authResult struct {
@@ -238,6 +249,17 @@ func (b *backend) Login(ctx context.Context, req *logical.Request, username, pas
 					return nil, logical.ErrorResponse(fmt.Sprintf("okta auth failed creating verify request: %v", err)), nil, nil
 				}
 				rsp, err := shim.Do(verifyReq, &result)
+
+				// Store number challenge if found
+				numberChallenge := result.Embedded.Factor.Embedded.Challenge.CorrectAnswer
+				if numberChallenge != nil {
+					if nonce == "" {
+						return nil, logical.ErrorResponse("nonce must be provided during login request when presented with number challenge"), nil, nil
+					}
+
+					b.verifyCache.SetDefault(nonce, *numberChallenge)
+				}
+
 				if err != nil {
 					return nil, logical.ErrorResponse(fmt.Sprintf("Okta auth failed checking loop: %v", err)), nil, nil
 				}
@@ -246,7 +268,7 @@ func (b *backend) Login(ctx context.Context, req *logical.Request, username, pas
 				}
 
 				select {
-				case <-time.After(500 * time.Millisecond):
+				case <-time.After(1 * time.Second):
 					// Continue
 				case <-ctx.Done():
 					return nil, logical.ErrorResponse("exiting pending mfa challenge"), nil, nil

builtin/credential/okta/cli.go

@@ -1,10 +1,13 @@
 package okta
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 	"strings"
+	"time"
 
+	"github.com/hashicorp/go-secure-stdlib/base62"
 	pwd "github.com/hashicorp/go-secure-stdlib/password"
 	"github.com/hashicorp/vault/api"
 )
@@ -48,6 +51,30 @@ func (h *CLIHandler) Auth(c *api.Client, m map[string]string) (*api.Secret, erro
 		data["provider"] = provider
 	}
 
+	nonce := base62.MustRandom(20)
+	data["nonce"] = nonce
+
+	// Create a done channel to signal termination of the login so that we can
+	// clean up the goroutine
+	doneCh := make(chan struct{})
+	defer close(doneCh)
+
+	go func() {
+		for {
+			select {
+			case <-doneCh:
+				return
+			case <-time.After(time.Second):
+			}
+
+			resp, _ := c.Logical().Read(fmt.Sprintf("auth/%s/verify/%s", mount, nonce))
+			if resp != nil {
+				fmt.Fprintf(os.Stderr, "In Okta Verify, tap the number %q\n", resp.Data["correct_answer"].(json.Number))
+				return
+			}
+		}
+	}()
+
 	path := fmt.Sprintf("auth/%s/login/%s", mount, username)
 	secret, err := c.Logical().Write(path, data)
 	if err != nil {

builtin/credential/okta/path_login.go

@@ -34,6 +34,12 @@ func pathLogin(b *backend) *framework.Path {
 				Type:        framework.TypeString,
 				Description: "TOTP passcode.",
 			},
+			"nonce": {
+				Type: framework.TypeString,
+				Description: `Nonce provided if performing login that requires 
+number verification challenge. Logins through the vault login CLI command will 
+automatically generate a nonce.`,
+			},
 			"provider": {
 				Type:        framework.TypeString,
 				Description: "Preferred factor provider.",
@@ -73,12 +79,15 @@ func (b *backend) pathLogin(ctx context.Context, req *logical.Request, d *framew
 	username := d.Get("username").(string)
 	password := d.Get("password").(string)
 	totp := d.Get("totp").(string)
+	nonce := d.Get("nonce").(string)
 	preferredProvider := strings.ToUpper(d.Get("provider").(string))
 	if preferredProvider != "" && !strutil.StrListContains(b.getSupportedProviders(), preferredProvider) {
 		return logical.ErrorResponse(fmt.Sprintf("provider %s is not among the supported ones %v", preferredProvider, b.getSupportedProviders())), nil
 	}
 
-	policies, resp, groupNames, err := b.Login(ctx, req, username, password, totp, preferredProvider)
+	defer b.verifyCache.Delete(nonce)
+
+	policies, resp, groupNames, err := b.Login(ctx, req, username, password, totp, nonce, preferredProvider)
 	// Handle an internal error
 	if err != nil {
 		return nil, err
@@ -134,6 +143,7 @@ func (b *backend) pathLogin(ctx context.Context, req *logical.Request, d *framew
 func (b *backend) pathLoginRenew(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
 	username := req.Auth.Metadata["username"]
 	password := req.Auth.InternalData["password"].(string)
+	nonce := d.Get("nonce").(string)
 
 	cfg, err := b.getConfig(ctx, req)
 	if err != nil {
@@ -142,7 +152,7 @@ func (b *backend) pathLoginRenew(ctx context.Context, req *logical.Request, d *f
 
 	// No TOTP entry is possible on renew. If push MFA is enabled it will still be triggered, however.
 	// Sending "" as the totp will prompt the push action if it is configured.
-	loginPolicies, resp, groupNames, err := b.Login(ctx, req, username, password, "", "")
+	loginPolicies, resp, groupNames, err := b.Login(ctx, req, username, password, "", nonce, "")
 	if err != nil || (resp != nil && resp.IsError()) {
 		return resp, err
 	}
@@ -172,6 +182,41 @@ func (b *backend) pathLoginRenew(ctx context.Context, req *logical.Request, d *f
 	return resp, nil
 }
 
+func pathVerify(b *backend) *framework.Path {
+	return &framework.Path{
+		Pattern: `verify/(?P<nonce>.+)`,
+		Fields: map[string]*framework.FieldSchema{
+			"nonce": {
+				Type: framework.TypeString,
+				Description: `Nonce provided during a login request to
+retrieve the number verification challenge for the matching request.`,
+			},
+		},
+		Operations: map[logical.Operation]framework.OperationHandler{
+			logical.ReadOperation: &framework.PathOperation{
+				Callback: b.pathVerify,
+			},
+		},
+	}
+}
+
+func (b *backend) pathVerify(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
+	nonce := d.Get("nonce").(string)
+
+	correctRaw, ok := b.verifyCache.Get(nonce)
+	if !ok {
+		return nil, nil
+	}
+
+	resp := &logical.Response{
+		Data: map[string]interface{}{
+			"correct_answer": correctRaw.(int),
+		},
+	}
+
+	return resp, nil
+}
+
 func (b *backend) getConfig(ctx context.Context, req *logical.Request) (*ConfigEntry, error) {
 	cfg, err := b.Config(ctx, req.Storage)
 	if err != nil {

changelog/15361.txt

@@ -0,0 +1,5 @@
+```release-note:improvement
+auth/okta: Add support for performing [the number
+challenge](https://help.okta.com/en-us/Content/Topics/Mobile/ov-admin-config.htm?cshid=csh-okta-verify-number-challenge-v1#enable-number-challenge)
+during an Okta Verify push challenge
+```

website/content/api-docs/auth/okta.mdx

@@ -353,6 +353,8 @@ Login with the username and password.
 - `password` `(string: <required>)` - Password for the authenticating user.
 - `totp` `(string: <optional>)` - Okta Verify TOTP passcode.
 - `provider` `(string: <optional>)` - MFA TOTP factor provider. `GOOGLE` and `OKTA` are currently supported.
+- `nonce` `(string: <optional>)` - Nonce provided during a login request to
+  retrieve the number verification challenge for the matching request.
 
 ### Sample Payload
 
@@ -373,7 +375,7 @@ $ curl \
 
 ### Sample Response
 
-```javascript
+```json
 {
   "lease_id": "",
   "renewable": false,
@@ -388,8 +390,45 @@ $ curl \
       "username": "fred",
       "policies": "default"
     },
-  },
     "lease_duration": 7200,
     "renewable": true
+  }
 }
 ```
+
+## Verify
+
+Verify a number challenge that may result from an Okta Verify Push challenge.
+
+| Method | Path                         |
+| :----- | :--------------------------- |
+| `GET`  | `/auth/okta/verify/:nonce`   |
+
+### Parameters
+
+- `nonce` `(string: <required>)` - Nonce provided if performing login that
+requires number verification challenge. Logins through the vault login CLI
+command will automatically generate a nonce.
+
+### Sample Request
+
+```shell-session
+$ curl \
+    http://127.0.0.1:8200/v1/auth/okta/nonce/BCR66Ru6oJKPtC00PxJJ
+```
+
+### Sample Response
+
+```json
+{
+  "request_id": "de6a8029-79e5-1dd1-dbe9-6405166b3f94",
+  "lease_id": "",
+  "lease_duration": 0,
+  "renewable": false,
+  "data": {
+    "correct_answer": 94
+  },
+  "warnings": null
+}
+```
+