145 lines
3.5 KiB
Go
145 lines
3.5 KiB
Go
// Copyright 2018 Drone.IO Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package token
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import (
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"fmt"
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"net/http"
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"github.com/dgrijalva/jwt-go"
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)
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type SecretFunc func(*Token) (string, error)
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const (
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UserToken = "user"
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SessToken = "sess"
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HookToken = "hook"
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CsrfToken = "csrf"
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AgentToken = "agent"
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)
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// Default algorithm used to sign JWT tokens.
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const SignerAlgo = "HS256"
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type Token struct {
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Kind string
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Text string
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}
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func Parse(raw string, fn SecretFunc) (*Token, error) {
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token := &Token{}
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parsed, err := jwt.Parse(raw, keyFunc(token, fn))
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if err != nil {
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return nil, err
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} else if !parsed.Valid {
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return nil, jwt.ValidationError{}
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}
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return token, nil
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}
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func ParseRequest(r *http.Request, fn SecretFunc) (*Token, error) {
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var token = r.Header.Get("Authorization")
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// first we attempt to get the token from the
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// authorization header.
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if len(token) != 0 {
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token = r.Header.Get("Authorization")
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fmt.Sscanf(token, "Bearer %s", &token)
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return Parse(token, fn)
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}
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// then we attempt to get the token from the
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// access_token url query parameter
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token = r.FormValue("access_token")
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if len(token) != 0 {
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return Parse(token, fn)
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}
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// and finally we attempt to get the token from
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// the user session cookie
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cookie, err := r.Cookie("user_sess")
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if err != nil {
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return nil, err
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}
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return Parse(cookie.Value, fn)
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}
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func CheckCsrf(r *http.Request, fn SecretFunc) error {
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// get and options requests are always
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// enabled, without CSRF checks.
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switch r.Method {
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case "GET", "OPTIONS":
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return nil
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}
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// parse the raw CSRF token value and validate
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raw := r.Header.Get("X-CSRF-TOKEN")
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_, err := Parse(raw, fn)
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return err
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}
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func New(kind, text string) *Token {
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return &Token{Kind: kind, Text: text}
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}
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// Sign signs the token using the given secret hash
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// and returns the string value.
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func (t *Token) Sign(secret string) (string, error) {
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return t.SignExpires(secret, 0)
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}
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// Sign signs the token using the given secret hash
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// with an expiration date.
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func (t *Token) SignExpires(secret string, exp int64) (string, error) {
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token := jwt.New(jwt.SigningMethodHS256)
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token.Claims["type"] = t.Kind
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token.Claims["text"] = t.Text
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if exp > 0 {
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token.Claims["exp"] = float64(exp)
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}
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return token.SignedString([]byte(secret))
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}
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func keyFunc(token *Token, fn SecretFunc) jwt.Keyfunc {
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return func(t *jwt.Token) (interface{}, error) {
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// validate the correct algorithm is being used
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if t.Method.Alg() != SignerAlgo {
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return nil, jwt.ErrSignatureInvalid
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}
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// extract the token kind and cast to
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// the expected type.
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kindv, ok := t.Claims["type"]
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if !ok {
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return nil, jwt.ValidationError{}
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}
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token.Kind, _ = kindv.(string)
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// extract the token value and cast to
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// exepected type.
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textv, ok := t.Claims["text"]
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if !ok {
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return nil, jwt.ValidationError{}
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}
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token.Text, _ = textv.(string)
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// invoke the callback function to retrieve
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// the secret key used to verify
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secret, err := fn(token)
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return []byte(secret), err
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}
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}
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