136 lines
4.8 KiB
Go
136 lines
4.8 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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"bytes"
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"io"
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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", "readonly").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 + `$`)).OnElements("span")
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// Allow classes for anchors
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sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`ref-issue`)).OnElements("a")
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// Allow classes for task lists
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sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`task-list-item`)).OnElements("li")
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// Allow icons
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sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^icon(\s+[\p{L}\p{N}_-]+)+$`)).OnElements("i")
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// Allow unlabelled labels
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sanitizer.policy.AllowNoAttrs().OnElements("label")
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// Allow classes for emojis
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sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`emoji`)).OnElements("img")
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// Allow icons, checkboxes and emojis on span
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sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^((icon(\s+[\p{L}\p{N}_-]+)+)|(ui checkbox)|(ui checked checkbox)|(emoji))$`)).OnElements("span")
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// Allow generally safe attributes
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generalSafeAttrs := []string{"abbr", "accept", "accept-charset",
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"accesskey", "action", "align", "alt",
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"aria-describedby", "aria-hidden", "aria-label", "aria-labelledby",
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"axis", "border", "cellpadding", "cellspacing", "char",
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"charoff", "charset", "checked",
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"clear", "cols", "colspan", "color",
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"compact", "coords", "datetime", "dir",
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"disabled", "enctype", "for", "frame",
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"headers", "height", "hreflang",
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"hspace", "ismap", "label", "lang",
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"maxlength", "media", "method",
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"multiple", "name", "nohref", "noshade",
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"nowrap", "open", "prompt", "readonly", "rel", "rev",
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"rows", "rowspan", "rules", "scope",
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"selected", "shape", "size", "span",
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"start", "summary", "tabindex", "target",
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"title", "type", "usemap", "valign", "value",
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"vspace", "width", "itemprop",
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}
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generalSafeElements := []string{
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"h1", "h2", "h3", "h4", "h5", "h6", "h7", "h8", "br", "b", "i", "strong", "em", "a", "pre", "code", "img", "tt",
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"div", "ins", "del", "sup", "sub", "p", "ol", "ul", "table", "thead", "tbody", "tfoot", "blockquote",
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"dl", "dt", "dd", "kbd", "q", "samp", "var", "hr", "ruby", "rt", "rp", "li", "tr", "td", "th", "s", "strike", "summary",
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"details", "caption", "figure", "figcaption",
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"abbr", "bdo", "cite", "dfn", "mark", "small", "span", "time", "wbr",
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}
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sanitizer.policy.AllowAttrs(generalSafeAttrs...).OnElements(generalSafeElements...)
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sanitizer.policy.AllowAttrs("itemscope", "itemtype").OnElements("div")
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// FIXME: Need to handle longdesc in img but there is no easy way to do it
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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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// SanitizeReader sanitizes a Reader
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func SanitizeReader(r io.Reader) *bytes.Buffer {
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NewSanitizer()
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return sanitizer.policy.SanitizeReader(r)
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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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