93 lines
2.7 KiB
Go
93 lines
2.7 KiB
Go
// Copyright 2014 Manu Martinez-Almeida. All rights reserved.
|
|
// Use of this source code is governed by a MIT style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package gin
|
|
|
|
import (
|
|
"crypto/subtle"
|
|
"encoding/base64"
|
|
"errors"
|
|
"sort"
|
|
)
|
|
|
|
const (
|
|
AuthUserKey = "user"
|
|
)
|
|
|
|
type (
|
|
BasicAuthPair struct {
|
|
Code string
|
|
User string
|
|
}
|
|
Accounts map[string]string
|
|
Pairs []BasicAuthPair
|
|
)
|
|
|
|
func (a Pairs) Len() int { return len(a) }
|
|
func (a Pairs) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
|
|
func (a Pairs) Less(i, j int) bool { return a[i].Code < a[j].Code }
|
|
|
|
func processCredentials(accounts Accounts) (Pairs, error) {
|
|
if len(accounts) == 0 {
|
|
return nil, errors.New("Empty list of authorized credentials.")
|
|
}
|
|
pairs := make(Pairs, 0, len(accounts))
|
|
for user, password := range accounts {
|
|
if len(user) == 0 || len(password) == 0 {
|
|
return nil, errors.New("User or password is empty")
|
|
}
|
|
base := user + ":" + password
|
|
code := "Basic " + base64.StdEncoding.EncodeToString([]byte(base))
|
|
pairs = append(pairs, BasicAuthPair{code, user})
|
|
}
|
|
// We have to sort the credentials in order to use bsearch later.
|
|
sort.Sort(pairs)
|
|
return pairs, nil
|
|
}
|
|
|
|
func secureCompare(given, actual string) bool {
|
|
if subtle.ConstantTimeEq(int32(len(given)), int32(len(actual))) == 1 {
|
|
return subtle.ConstantTimeCompare([]byte(given), []byte(actual)) == 1
|
|
} else {
|
|
/* Securely compare actual to itself to keep constant time, but always return false */
|
|
return subtle.ConstantTimeCompare([]byte(actual), []byte(actual)) == 1 && false
|
|
}
|
|
}
|
|
|
|
func searchCredential(pairs Pairs, auth string) string {
|
|
if len(auth) == 0 {
|
|
return ""
|
|
}
|
|
// Search user in the slice of allowed credentials
|
|
r := sort.Search(len(pairs), func(i int) bool { return pairs[i].Code >= auth })
|
|
if r < len(pairs) && secureCompare(pairs[r].Code, auth) {
|
|
return pairs[r].User
|
|
} else {
|
|
return ""
|
|
}
|
|
}
|
|
|
|
// Implements a basic Basic HTTP Authorization. It takes as argument a map[string]string where
|
|
// the key is the user name and the value is the password.
|
|
func BasicAuth(accounts Accounts) HandlerFunc {
|
|
|
|
pairs, err := processCredentials(accounts)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
return func(c *Context) {
|
|
// Search user in the slice of allowed credentials
|
|
user := searchCredential(pairs, c.Request.Header.Get("Authorization"))
|
|
if len(user) == 0 {
|
|
// Credentials doesn't match, we return 401 Unauthorized and abort request.
|
|
c.Writer.Header().Set("WWW-Authenticate", "Basic realm=\"Authorization Required\"")
|
|
c.Fail(401, errors.New("Unauthorized"))
|
|
} else {
|
|
// user is allowed, set UserId to key "user" in this context, the userId can be read later using
|
|
// c.Get(gin.AuthUserKey)
|
|
c.Set(AuthUserKey, user)
|
|
}
|
|
}
|
|
}
|