github.com/anakojm/hugo-katex@v0.0.0-20231023141351-42d6f5de9c0b/config/security/whitelist.go (about)

     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  // MarshalJSON is for internal use only.
    37  func (w Whitelist) MarshalJSON() ([]byte, error) {
    38  	if w.acceptNone {
    39  		return json.Marshal(acceptNoneKeyword)
    40  	}
    41  
    42  	return json.Marshal(w.patternsStrings)
    43  }
    44  
    45  // NewWhitelist creates a new Whitelist from zero or more patterns.
    46  // An empty patterns list or a pattern with the value 'none' will create
    47  // a whitelist that will Accept none.
    48  func NewWhitelist(patterns ...string) (Whitelist, error) {
    49  	if len(patterns) == 0 {
    50  		return Whitelist{acceptNone: true}, nil
    51  	}
    52  
    53  	var acceptSome bool
    54  	var patternsStrings []string
    55  
    56  	for _, p := range patterns {
    57  		if p == acceptNoneKeyword {
    58  			acceptSome = false
    59  			break
    60  		}
    61  
    62  		if ps := strings.TrimSpace(p); ps != "" {
    63  			acceptSome = true
    64  			patternsStrings = append(patternsStrings, ps)
    65  		}
    66  	}
    67  
    68  	if !acceptSome {
    69  		return Whitelist{
    70  			acceptNone: true,
    71  		}, nil
    72  	}
    73  
    74  	var patternsr []*regexp.Regexp
    75  
    76  	for i := 0; i < len(patterns); i++ {
    77  		p := strings.TrimSpace(patterns[i])
    78  		if p == "" {
    79  			continue
    80  		}
    81  		re, err := regexp.Compile(p)
    82  		if err != nil {
    83  			return Whitelist{}, fmt.Errorf("failed to compile whitelist pattern %q: %w", p, err)
    84  		}
    85  		patternsr = append(patternsr, re)
    86  	}
    87  
    88  	return Whitelist{patterns: patternsr, patternsStrings: patternsStrings}, nil
    89  }
    90  
    91  // MustNewWhitelist creates a new Whitelist from zero or more patterns and panics on error.
    92  func MustNewWhitelist(patterns ...string) Whitelist {
    93  	w, err := NewWhitelist(patterns...)
    94  	if err != nil {
    95  		panic(err)
    96  	}
    97  	return w
    98  }
    99  
   100  // Accept reports whether name is whitelisted.
   101  func (w Whitelist) Accept(name string) bool {
   102  	if w.acceptNone {
   103  		return false
   104  	}
   105  
   106  	for _, p := range w.patterns {
   107  		if p.MatchString(name) {
   108  			return true
   109  		}
   110  	}
   111  	return false
   112  }
   113  
   114  func (w Whitelist) String() string {
   115  	return fmt.Sprint(w.patternsStrings)
   116  }