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	* Support custom sanitization policy Allowing the gitea administrator to configure sanitization policy allows them to couple external renders and custom templates to support more markup. In particular, the `pandoc` renderer allows generating KaTeX annotations, wrapping them in `<span>` elements with class `math` and either `inline` or `display` (depending on whether or not inline or block mode was requested). This iteration gives the administrator whitelisting powers; carefully crafted regexes will thus let through only the desired attributes necessary to support their custom markup. Resolves: #9054 Signed-off-by: Alexander Scheel <alexander.m.scheel@gmail.com> * Document new sanitization configuration - Adds basic documentation to app.ini.sample, - Adds an example to the Configuration Cheat Sheet, and - Adds extended information to External Renderers section. Signed-off-by: Alexander Scheel <alexander.m.scheel@gmail.com> * Drop extraneous length check in newMarkupSanitizer(...) Signed-off-by: Alexander Scheel <alexander.m.scheel@gmail.com> * Fix plural ELEMENT and ALLOW_ATTR in docs These were left over from their initial names. Make them singular to conform with the current expectations. Signed-off-by: Alexander Scheel <alexander.m.scheel@gmail.com>
		
			
				
	
	
		
			79 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			79 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| // Copyright 2017 The Gitea Authors. All rights reserved.
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| // Copyright 2017 The Gogs Authors. All rights reserved.
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| // Use of this source code is governed by a MIT-style
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| // license that can be found in the LICENSE file.
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| 
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| package markup
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| 
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| import (
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| 	"regexp"
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| 	"sync"
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| 
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| 	"code.gitea.io/gitea/modules/setting"
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| 
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| 	"github.com/microcosm-cc/bluemonday"
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| )
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| 
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| // Sanitizer is a protection wrapper of *bluemonday.Policy which does not allow
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| // any modification to the underlying policies once it's been created.
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| type Sanitizer struct {
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| 	policy *bluemonday.Policy
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| 	init   sync.Once
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| }
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| 
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| var sanitizer = &Sanitizer{}
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| 
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| // NewSanitizer initializes sanitizer with allowed attributes based on settings.
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| // Multiple calls to this function will only create one instance of Sanitizer during
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| // entire application lifecycle.
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| func NewSanitizer() {
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| 	sanitizer.init.Do(func() {
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| 		ReplaceSanitizer()
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| 	})
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| }
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| 
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| // ReplaceSanitizer replaces the current sanitizer to account for changes in settings
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| func ReplaceSanitizer() {
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| 	sanitizer.policy = bluemonday.UGCPolicy()
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| 	// We only want to allow HighlightJS specific classes for code blocks
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| 	sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^language-\w+$`)).OnElements("code")
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| 
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| 	// Checkboxes
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| 	sanitizer.policy.AllowAttrs("type").Matching(regexp.MustCompile(`^checkbox$`)).OnElements("input")
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| 	sanitizer.policy.AllowAttrs("checked", "disabled").OnElements("input")
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| 
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| 	// Custom URL-Schemes
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| 	sanitizer.policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
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| 
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| 	// Allow keyword markup
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| 	sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^` + keywordClass + `$`)).OnElements("span")
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| 
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| 	// Allow <kbd> tags for keyboard shortcut styling
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| 	sanitizer.policy.AllowElements("kbd")
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| 
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| 	// Custom keyword markup
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| 	for _, rule := range setting.ExternalSanitizerRules {
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| 		if rule.Regexp != nil {
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| 			sanitizer.policy.AllowAttrs(rule.AllowAttr).Matching(rule.Regexp).OnElements(rule.Element)
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| 		} else {
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| 			sanitizer.policy.AllowAttrs(rule.AllowAttr).OnElements(rule.Element)
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| 		}
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| 	}
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| }
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| 
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| // Sanitize takes a string that contains a HTML fragment or document and applies policy whitelist.
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| func Sanitize(s string) string {
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| 	NewSanitizer()
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| 	return sanitizer.policy.Sanitize(s)
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| }
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| 
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| // SanitizeBytes takes a []byte slice that contains a HTML fragment or document and applies policy whitelist.
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| func SanitizeBytes(b []byte) []byte {
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| 	if len(b) == 0 {
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| 		// nothing to sanitize
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| 		return b
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| 	}
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| 	NewSanitizer()
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| 	return sanitizer.policy.SanitizeBytes(b)
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| }
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