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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>
78 lines
2.4 KiB
Go
78 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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package markup
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import (
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"regexp"
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"sync"
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"code.gitea.io/gitea/modules/setting"
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"github.com/microcosm-cc/bluemonday"
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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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var sanitizer = &Sanitizer{}
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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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// 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+$`)).OnElements("code")
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// Checkboxes
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sanitizer.policy.AllowAttrs("type").Matching(regexp.MustCompile(`^checkbox$`)).OnElements("input")
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sanitizer.policy.AllowAttrs("checked", "disabled").OnElements("input")
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// Custom URL-Schemes
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sanitizer.policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
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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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// Allow <kbd> tags for keyboard shortcut styling
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sanitizer.policy.AllowElements("kbd")
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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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// 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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// 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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