whitelist.go (2274B)
1 // Copyright 2021 The Hugo Authors. All rights reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // http://www.apache.org/licenses/LICENSE-2.0 7 // 8 // Unless required by applicable law or agreed to in writing, software 9 // distributed under the License is distributed on an "AS IS" BASIS, 10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 11 // See the License for the specific language governing permissions and 12 // limitations under the License. 13 14 package security 15 16 import ( 17 "encoding/json" 18 "fmt" 19 "regexp" 20 "strings" 21 ) 22 23 const ( 24 acceptNoneKeyword = "none" 25 ) 26 27 // Whitelist holds a whitelist. 28 type Whitelist struct { 29 acceptNone bool 30 patterns []*regexp.Regexp 31 32 // Store this for debugging/error reporting 33 patternsStrings []string 34 } 35 36 func (w Whitelist) MarshalJSON() ([]byte, error) { 37 if w.acceptNone { 38 return json.Marshal(acceptNoneKeyword) 39 } 40 41 return json.Marshal(w.patternsStrings) 42 } 43 44 // NewWhitelist creates a new Whitelist from zero or more patterns. 45 // An empty patterns list or a pattern with the value 'none' will create 46 // a whitelist that will Accept noone. 47 func NewWhitelist(patterns ...string) Whitelist { 48 if len(patterns) == 0 { 49 return Whitelist{acceptNone: true} 50 } 51 52 var acceptSome bool 53 var patternsStrings []string 54 55 for _, p := range patterns { 56 if p == acceptNoneKeyword { 57 acceptSome = false 58 break 59 } 60 61 if ps := strings.TrimSpace(p); ps != "" { 62 acceptSome = true 63 patternsStrings = append(patternsStrings, ps) 64 } 65 } 66 67 if !acceptSome { 68 return Whitelist{ 69 acceptNone: true, 70 } 71 } 72 73 var patternsr []*regexp.Regexp 74 75 for i := 0; i < len(patterns); i++ { 76 p := strings.TrimSpace(patterns[i]) 77 if p == "" { 78 continue 79 } 80 patternsr = append(patternsr, regexp.MustCompile(p)) 81 } 82 83 return Whitelist{patterns: patternsr, patternsStrings: patternsStrings} 84 } 85 86 // Accepted reports whether name is whitelisted. 87 func (w Whitelist) Accept(name string) bool { 88 if w.acceptNone { 89 return false 90 } 91 92 for _, p := range w.patterns { 93 if p.MatchString(name) { 94 return true 95 } 96 } 97 return false 98 } 99 100 func (w Whitelist) String() string { 101 return fmt.Sprint(w.patternsStrings) 102 }