forked from ebhomengo/niki
298 lines
11 KiB
Go
298 lines
11 KiB
Go
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// SPDX-License-Identifier: MIT
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// SPDX-FileCopyrightText: © 2016 LabStack and Echo contributors
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package echojwt
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import (
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"errors"
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"fmt"
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"net/http"
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"github.com/golang-jwt/jwt/v5"
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"github.com/labstack/echo/v4"
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"github.com/labstack/echo/v4/middleware"
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)
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// Config defines the config for JWT middleware.
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type Config struct {
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// Skipper defines a function to skip middleware.
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Skipper middleware.Skipper
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// BeforeFunc defines a function which is executed just before the middleware.
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BeforeFunc middleware.BeforeFunc
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// SuccessHandler defines a function which is executed for a valid token.
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SuccessHandler func(c echo.Context)
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// ErrorHandler defines a function which is executed when all lookups have been done and none of them passed Validator
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// function. ErrorHandler is executed with last missing (ErrExtractionValueMissing) or an invalid key.
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// It may be used to define a custom JWT error.
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//
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// Note: when error handler swallows the error (returns nil) middleware continues handler chain execution towards handler.
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// This is useful in cases when portion of your site/api is publicly accessible and has extra features for authorized users
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// In that case you can use ErrorHandler to set default public JWT token value to request and continue with handler chain.
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ErrorHandler func(c echo.Context, err error) error
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// ContinueOnIgnoredError allows the next middleware/handler to be called when ErrorHandler decides to
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// ignore the error (by returning `nil`).
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// This is useful when parts of your site/api allow public access and some authorized routes provide extra functionality.
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// In that case you can use ErrorHandler to set a default public JWT token value in the request context
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// and continue. Some logic down the remaining execution chain needs to check that (public) token value then.
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ContinueOnIgnoredError bool
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// Context key to store user information from the token into context.
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// Optional. Default value "user".
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ContextKey string
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// Signing key to validate token.
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// This is one of the three options to provide a token validation key.
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// The order of precedence is a user-defined KeyFunc, SigningKeys and SigningKey.
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// Required if neither user-defined KeyFunc nor SigningKeys is provided.
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SigningKey interface{}
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// Map of signing keys to validate token with kid field usage.
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// This is one of the three options to provide a token validation key.
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// The order of precedence is a user-defined KeyFunc, SigningKeys and SigningKey.
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// Required if neither user-defined KeyFunc nor SigningKey is provided.
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SigningKeys map[string]interface{}
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// Signing method used to check the token's signing algorithm.
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// Optional. Default value HS256.
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SigningMethod string
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// KeyFunc defines a user-defined function that supplies the public key for a token validation.
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// The function shall take care of verifying the signing algorithm and selecting the proper key.
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// A user-defined KeyFunc can be useful if tokens are issued by an external party.
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// Used by default ParseTokenFunc implementation.
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//
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// When a user-defined KeyFunc is provided, SigningKey, SigningKeys, and SigningMethod are ignored.
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// This is one of the three options to provide a token validation key.
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// The order of precedence is a user-defined KeyFunc, SigningKeys and SigningKey.
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// Required if neither SigningKeys nor SigningKey is provided.
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// Not used if custom ParseTokenFunc is set.
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// Default to an internal implementation verifying the signing algorithm and selecting the proper key.
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KeyFunc jwt.Keyfunc
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// TokenLookup is a string in the form of "<source>:<name>" or "<source>:<name>,<source>:<name>" that is used
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// to extract token from the request.
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// Optional. Default value "header:Authorization".
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// Possible values:
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// - "header:<name>" or "header:<name>:<cut-prefix>"
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// `<cut-prefix>` is argument value to cut/trim prefix of the extracted value. This is useful if header
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// value has static prefix like `Authorization: <auth-scheme> <authorisation-parameters>` where part that we
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// want to cut is `<auth-scheme> ` note the space at the end.
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// In case of JWT tokens `Authorization: Bearer <token>` prefix we cut is `Bearer `.
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// If prefix is left empty the whole value is returned.
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// - "query:<name>"
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// - "param:<name>"
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// - "cookie:<name>"
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// - "form:<name>"
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// Multiple sources example:
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// - "header:Authorization:Bearer ,cookie:myowncookie"
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TokenLookup string
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// TokenLookupFuncs defines a list of user-defined functions that extract JWT token from the given context.
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// This is one of the two options to provide a token extractor.
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// The order of precedence is user-defined TokenLookupFuncs, and TokenLookup.
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// You can also provide both if you want.
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TokenLookupFuncs []middleware.ValuesExtractor
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// ParseTokenFunc defines a user-defined function that parses token from given auth. Returns an error when token
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// parsing fails or parsed token is invalid.
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// Defaults to implementation using `github.com/golang-jwt/jwt` as JWT implementation library
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ParseTokenFunc func(c echo.Context, auth string) (interface{}, error)
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// Claims are extendable claims data defining token content. Used by default ParseTokenFunc implementation.
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// Not used if custom ParseTokenFunc is set.
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// Optional. Defaults to function returning jwt.MapClaims
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NewClaimsFunc func(c echo.Context) jwt.Claims
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}
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const (
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// AlgorithmHS256 is token signing algorithm
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AlgorithmHS256 = "HS256"
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)
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// ErrJWTMissing denotes an error raised when JWT token value could not be extracted from request
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var ErrJWTMissing = echo.NewHTTPError(http.StatusUnauthorized, "missing or malformed jwt")
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// ErrJWTInvalid denotes an error raised when JWT token value is invalid or expired
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var ErrJWTInvalid = echo.NewHTTPError(http.StatusUnauthorized, "invalid or expired jwt")
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// TokenParsingError is catch all type for all errors that occur when token is parsed. In case of library default
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// token parsing functions are being used this error instance wraps TokenError. This helps to distinguish extractor
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// errors from token parsing errors even if custom extractors or token parsing functions are being used that have
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// their own custom errors.
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type TokenParsingError struct {
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Err error
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}
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// Is checks if target error is same as TokenParsingError
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func (e TokenParsingError) Is(target error) bool { return target == ErrJWTInvalid } // to provide some compatibility with older error handling logic
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func (e *TokenParsingError) Error() string { return e.Err.Error() }
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func (e *TokenParsingError) Unwrap() error { return e.Err }
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// TokenError is used to return error with error occurred JWT token when processing JWT token
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type TokenError struct {
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Token *jwt.Token
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Err error
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}
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func (e *TokenError) Error() string { return e.Err.Error() }
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func (e *TokenError) Unwrap() error { return e.Err }
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// JWT returns a JSON Web Token (JWT) auth middleware.
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//
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// For valid token, it sets the user in context and calls next handler.
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// For invalid token, it returns "401 - Unauthorized" error.
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// For missing token, it returns "400 - Bad Request" error.
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//
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// See: https://jwt.io/introduction
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func JWT(signingKey interface{}) echo.MiddlewareFunc {
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return WithConfig(Config{SigningKey: signingKey})
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}
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// WithConfig returns a JSON Web Token (JWT) auth middleware or panics if configuration is invalid.
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//
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// For valid token, it sets the user in context and calls next handler.
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// For invalid token, it returns "401 - Unauthorized" error.
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// For missing token, it returns "400 - Bad Request" error.
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//
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// See: https://jwt.io/introduction
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func WithConfig(config Config) echo.MiddlewareFunc {
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mw, err := config.ToMiddleware()
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if err != nil {
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panic(err)
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}
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return mw
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}
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// ToMiddleware converts Config to middleware or returns an error for invalid configuration
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func (config Config) ToMiddleware() (echo.MiddlewareFunc, error) {
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if config.Skipper == nil {
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config.Skipper = middleware.DefaultSkipper
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}
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if config.ContextKey == "" {
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config.ContextKey = "user"
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}
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if config.TokenLookup == "" && len(config.TokenLookupFuncs) == 0 {
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config.TokenLookup = "header:Authorization:Bearer "
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}
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if config.SigningMethod == "" {
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config.SigningMethod = AlgorithmHS256
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}
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if config.NewClaimsFunc == nil {
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config.NewClaimsFunc = func(c echo.Context) jwt.Claims {
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return jwt.MapClaims{}
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}
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}
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if config.SigningKey == nil && len(config.SigningKeys) == 0 && config.KeyFunc == nil && config.ParseTokenFunc == nil {
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return nil, errors.New("jwt middleware requires signing key")
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}
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if config.KeyFunc == nil {
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config.KeyFunc = config.defaultKeyFunc
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}
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if config.ParseTokenFunc == nil {
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config.ParseTokenFunc = config.defaultParseTokenFunc
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}
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extractors, ceErr := CreateExtractors(config.TokenLookup)
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if ceErr != nil {
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return nil, ceErr
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}
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if len(config.TokenLookupFuncs) > 0 {
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extractors = append(config.TokenLookupFuncs, extractors...)
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}
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return func(next echo.HandlerFunc) echo.HandlerFunc {
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return func(c echo.Context) error {
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if config.Skipper(c) {
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return next(c)
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}
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if config.BeforeFunc != nil {
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config.BeforeFunc(c)
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}
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var lastExtractorErr error
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var lastTokenErr error
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for _, extractor := range extractors {
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auths, extrErr := extractor(c)
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if extrErr != nil {
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lastExtractorErr = extrErr
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continue
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}
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for _, auth := range auths {
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token, err := config.ParseTokenFunc(c, auth)
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if err != nil {
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lastTokenErr = err
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continue
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}
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// Store user information from token into context.
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c.Set(config.ContextKey, token)
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if config.SuccessHandler != nil {
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config.SuccessHandler(c)
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}
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return next(c)
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}
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}
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// prioritize token errors over extracting errors as parsing is occurs further in process, meaning we managed to
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// extract at least one token and failed to parse it
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var err error
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if lastTokenErr != nil {
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err = &TokenParsingError{Err: lastTokenErr}
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} else if lastExtractorErr != nil {
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err = &TokenExtractionError{Err: lastExtractorErr}
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}
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if config.ErrorHandler != nil {
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tmpErr := config.ErrorHandler(c, err)
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if config.ContinueOnIgnoredError && tmpErr == nil {
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return next(c)
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}
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return tmpErr
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}
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message := "invalid or expired jwt"
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if lastTokenErr == nil {
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message = "missing or malformed jwt"
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}
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return echo.NewHTTPError(http.StatusUnauthorized, message).SetInternal(err)
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}
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}, nil
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}
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// defaultKeyFunc creates JWTGo implementation for KeyFunc.
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//
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// error returns TokenError.
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func (config Config) defaultKeyFunc(token *jwt.Token) (interface{}, error) {
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if token.Method.Alg() != config.SigningMethod {
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return nil, &TokenError{Token: token, Err: fmt.Errorf("unexpected jwt signing method=%v", token.Header["alg"])}
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}
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if len(config.SigningKeys) == 0 {
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return config.SigningKey, nil
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}
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if kid, ok := token.Header["kid"].(string); ok {
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if key, ok := config.SigningKeys[kid]; ok {
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return key, nil
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}
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}
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return nil, &TokenError{Token: token, Err: fmt.Errorf("unexpected jwt key id=%v", token.Header["kid"])}
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}
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// defaultParseTokenFunc creates JWTGo implementation for ParseTokenFunc.
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//
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// error returns TokenError.
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func (config Config) defaultParseTokenFunc(c echo.Context, auth string) (interface{}, error) {
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token, err := jwt.ParseWithClaims(auth, config.NewClaimsFunc(c), config.KeyFunc)
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if err != nil {
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return nil, &TokenError{Token: token, Err: err}
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}
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if !token.Valid {
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return nil, &TokenError{Token: token, Err: errors.New("invalid token")}
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}
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return token, nil
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}
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