Support webauthn (#17957)

Migrate from U2F to Webauthn

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

vendor/github.com/duo-labs/webauthn/protocol/client.go

@@ -0,0 +1,112 @@
+package protocol
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+// CollectedClientData represents the contextual bindings of both the WebAuthn Relying Party
+// and the client. It is a key-value mapping whose keys are strings. Values can be any type
+// that has a valid encoding in JSON. Its structure is defined by the following Web IDL.
+// https://www.w3.org/TR/webauthn/#sec-client-data
+type CollectedClientData struct {
+	// Type the string "webauthn.create" when creating new credentials,
+	// and "webauthn.get" when getting an assertion from an existing credential. The
+	// purpose of this member is to prevent certain types of signature confusion attacks
+	//(where an attacker substitutes one legitimate signature for another).
+	Type         CeremonyType  `json:"type"`
+	Challenge    string        `json:"challenge"`
+	Origin       string        `json:"origin"`
+	TokenBinding *TokenBinding `json:"tokenBinding,omitempty"`
+	// Chromium (Chrome) returns a hint sometimes about how to handle clientDataJSON in a safe manner
+	Hint string `json:"new_keys_may_be_added_here,omitempty"`
+}
+
+type CeremonyType string
+
+const (
+	CreateCeremony CeremonyType = "webauthn.create"
+	AssertCeremony CeremonyType = "webauthn.get"
+)
+
+type TokenBinding struct {
+	Status TokenBindingStatus `json:"status"`
+	ID     string             `json:"id,omitempty"`
+}
+
+type TokenBindingStatus string
+
+const (
+	// Indicates token binding was used when communicating with the
+	// Relying Party. In this case, the id member MUST be present.
+	Present TokenBindingStatus = "present"
+	// Indicates token binding was used when communicating with the
+	// negotiated when communicating with the Relying Party.
+	Supported TokenBindingStatus = "supported"
+	// Indicates token binding not supported
+	// when communicating with the Relying Party.
+	NotSupported TokenBindingStatus = "not-supported"
+)
+
+// Returns the origin per the HTML spec: (scheme)://(host)[:(port)]
+func FullyQualifiedOrigin(u *url.URL) string {
+	return fmt.Sprintf("%s://%s", u.Scheme, u.Host)
+}
+
+// Handles steps 3 through 6 of verfying the registering client data of a
+// new credential and steps 7 through 10 of verifying an authentication assertion
+// See https://www.w3.org/TR/webauthn/#registering-a-new-credential
+// and https://www.w3.org/TR/webauthn/#verifying-assertion
+func (c *CollectedClientData) Verify(storedChallenge string, ceremony CeremonyType, relyingPartyOrigin string) error {
+
+	// Registration Step 3. Verify that the value of C.type is webauthn.create.
+
+	// Assertion Step 7. Verify that the value of C.type is the string webauthn.get.
+	if c.Type != ceremony {
+		err := ErrVerification.WithDetails("Error validating ceremony type")
+		err.WithInfo(fmt.Sprintf("Expected Value: %s\n Received: %s\n", ceremony, c.Type))
+		return err
+	}
+
+	// Registration Step 4. Verify that the value of C.challenge matches the challenge
+	// that was sent to the authenticator in the create() call.
+
+	// Assertion Step 8. Verify that the value of C.challenge matches the challenge
+	// that was sent to the authenticator in the PublicKeyCredentialRequestOptions
+	// passed to the get() call.
+
+	challenge := c.Challenge
+	if 0 != strings.Compare(storedChallenge, challenge) {
+		err := ErrVerification.WithDetails("Error validating challenge")
+		return err.WithInfo(fmt.Sprintf("Expected b Value: %#v\nReceived b: %#v\n", storedChallenge, challenge))
+	}
+
+	// Registration Step 5 & Assertion Step 9. Verify that the value of C.origin matches
+	// the Relying Party's origin.
+	clientDataOrigin, err := url.Parse(c.Origin)
+	if err != nil {
+		return ErrParsingData.WithDetails("Error decoding clientData origin as URL")
+	}
+
+	if !strings.EqualFold(FullyQualifiedOrigin(clientDataOrigin), relyingPartyOrigin) {
+		err := ErrVerification.WithDetails("Error validating origin")
+		return err.WithInfo(fmt.Sprintf("Expected Value: %s\n Received: %s\n", relyingPartyOrigin, FullyQualifiedOrigin(clientDataOrigin)))
+	}
+
+	// Registration Step 6 and Assertion Step 10. Verify that the value of C.tokenBinding.status
+	// matches the state of Token Binding for the TLS connection over which the assertion was
+	// obtained. If Token Binding was used on that TLS connection, also verify that C.tokenBinding.id
+	// matches the base64url encoding of the Token Binding ID for the connection.
+	if c.TokenBinding != nil {
+		if c.TokenBinding.Status == "" {
+			return ErrParsingData.WithDetails("Error decoding clientData, token binding present without status")
+		}
+		if c.TokenBinding.Status != Present && c.TokenBinding.Status != Supported && c.TokenBinding.Status != NotSupported {
+			return ErrParsingData.WithDetails("Error decoding clientData, token binding present with invalid status").WithInfo(fmt.Sprintf("Got: %s\n", c.TokenBinding.Status))
+		}
+	}
+	// Not yet fully implemented by the spec, browsers, and me.
+
+	return nil
+}