hugo/config/security/whitelist.go

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// Copyright 2021 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package security
import (
"encoding/json"
"fmt"
"regexp"
"strings"
)
const (
acceptNoneKeyword = "none"
)
// Whitelist holds a whitelist.
type Whitelist struct {
acceptNone bool
patterns []*regexp.Regexp
// Store this for debugging/error reporting
patternsStrings []string
}
// MarshalJSON is for internal use only.
func (w Whitelist) MarshalJSON() ([]byte, error) {
if w.acceptNone {
return json.Marshal(acceptNoneKeyword)
}
return json.Marshal(w.patternsStrings)
}
// NewWhitelist creates a new Whitelist from zero or more patterns.
// An empty patterns list or a pattern with the value 'none' will create
// a whitelist that will Accept noone.
func NewWhitelist(patterns ...string) Whitelist {
if len(patterns) == 0 {
return Whitelist{acceptNone: true}
}
var acceptSome bool
var patternsStrings []string
for _, p := range patterns {
if p == acceptNoneKeyword {
acceptSome = false
break
}
if ps := strings.TrimSpace(p); ps != "" {
acceptSome = true
patternsStrings = append(patternsStrings, ps)
}
}
if !acceptSome {
return Whitelist{
acceptNone: true,
}
}
var patternsr []*regexp.Regexp
for i := 0; i < len(patterns); i++ {
p := strings.TrimSpace(patterns[i])
if p == "" {
continue
}
patternsr = append(patternsr, regexp.MustCompile(p))
}
return Whitelist{patterns: patternsr, patternsStrings: patternsStrings}
}
// Accepted reports whether name is whitelisted.
func (w Whitelist) Accept(name string) bool {
if w.acceptNone {
return false
}
for _, p := range w.patterns {
if p.MatchString(name) {
return true
}
}
return false
}
func (w Whitelist) String() string {
return fmt.Sprint(w.patternsStrings)
}