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/golang-jwt/jwt/v4/token.go

@@ -0,0 +1,131 @@
+package jwt
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+	"time"
+)
+
+
+// DecodePaddingAllowed will switch the codec used for decoding JWTs respectively. Note that the JWS RFC7515
+// states that the tokens will utilize a Base64url encoding with no padding. Unfortunately, some implementations
+// of JWT are producing non-standard tokens, and thus require support for decoding. Note that this is a global
+// variable, and updating it will change the behavior on a package level, and is also NOT go-routine safe.
+// To use the non-recommended decoding, set this boolean to `true` prior to using this package.
+var DecodePaddingAllowed bool
+
+// TimeFunc provides the current time when parsing token to validate "exp" claim (expiration time).
+// You can override it to use another time value.  This is useful for testing or if your
+// server uses a different time zone than your tokens.
+var TimeFunc = time.Now
+
+// Keyfunc will be used by the Parse methods as a callback function to supply
+// the key for verification.  The function receives the parsed,
+// but unverified Token.  This allows you to use properties in the
+// Header of the token (such as `kid`) to identify which key to use.
+type Keyfunc func(*Token) (interface{}, error)
+
+// Token represents a JWT Token.  Different fields will be used depending on whether you're
+// creating or parsing/verifying a token.
+type Token struct {
+	Raw       string                 // The raw token.  Populated when you Parse a token
+	Method    SigningMethod          // The signing method used or to be used
+	Header    map[string]interface{} // The first segment of the token
+	Claims    Claims                 // The second segment of the token
+	Signature string                 // The third segment of the token.  Populated when you Parse a token
+	Valid     bool                   // Is the token valid?  Populated when you Parse/Verify a token
+}
+
+// New creates a new Token with the specified signing method and an empty map of claims.
+func New(method SigningMethod) *Token {
+	return NewWithClaims(method, MapClaims{})
+}
+
+// NewWithClaims creates a new Token with the specified signing method and claims.
+func NewWithClaims(method SigningMethod, claims Claims) *Token {
+	return &Token{
+		Header: map[string]interface{}{
+			"typ": "JWT",
+			"alg": method.Alg(),
+		},
+		Claims: claims,
+		Method: method,
+	}
+}
+
+// SignedString creates and returns a complete, signed JWT.
+// The token is signed using the SigningMethod specified in the token.
+func (t *Token) SignedString(key interface{}) (string, error) {
+	var sig, sstr string
+	var err error
+	if sstr, err = t.SigningString(); err != nil {
+		return "", err
+	}
+	if sig, err = t.Method.Sign(sstr, key); err != nil {
+		return "", err
+	}
+	return strings.Join([]string{sstr, sig}, "."), nil
+}
+
+// SigningString generates the signing string.  This is the
+// most expensive part of the whole deal.  Unless you
+// need this for something special, just go straight for
+// the SignedString.
+func (t *Token) SigningString() (string, error) {
+	var err error
+	parts := make([]string, 2)
+	for i := range parts {
+		var jsonValue []byte
+		if i == 0 {
+			if jsonValue, err = json.Marshal(t.Header); err != nil {
+				return "", err
+			}
+		} else {
+			if jsonValue, err = json.Marshal(t.Claims); err != nil {
+				return "", err
+			}
+		}
+
+		parts[i] = EncodeSegment(jsonValue)
+	}
+	return strings.Join(parts, "."), nil
+}
+
+// Parse parses, validates, verifies the signature and returns the parsed token.
+// keyFunc will receive the parsed token and should return the cryptographic key
+// for verifying the signature.
+// The caller is strongly encouraged to set the WithValidMethods option to
+// validate the 'alg' claim in the token matches the expected algorithm.
+// For more details about the importance of validating the 'alg' claim,
+// see https://auth0.com/blog/critical-vulnerabilities-in-json-web-token-libraries/
+func Parse(tokenString string, keyFunc Keyfunc, options ...ParserOption) (*Token, error) {
+	return NewParser(options...).Parse(tokenString, keyFunc)
+}
+
+func ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc, options ...ParserOption) (*Token, error) {
+	return NewParser(options...).ParseWithClaims(tokenString, claims, keyFunc)
+}
+
+// EncodeSegment encodes a JWT specific base64url encoding with padding stripped
+//
+// Deprecated: In a future release, we will demote this function to a non-exported function, since it
+// should only be used internally
+func EncodeSegment(seg []byte) string {
+	return base64.RawURLEncoding.EncodeToString(seg)
+}
+
+// DecodeSegment decodes a JWT specific base64url encoding with padding stripped
+//
+// Deprecated: In a future release, we will demote this function to a non-exported function, since it
+// should only be used internally
+func DecodeSegment(seg string) ([]byte, error) {
+	if DecodePaddingAllowed {
+		if l := len(seg) % 4; l > 0 {
+			seg += strings.Repeat("=", 4-l)
+		}
+		return base64.URLEncoding.DecodeString(seg)
+	}
+
+	return base64.RawURLEncoding.DecodeString(seg)
+}