mirror of
https://codeberg.org/forgejo/forgejo.git
synced 2024-12-22 12:54:53 -05:00
bb448f3dc2
- Fixes an XSS that was introduced in https://codeberg.org/forgejo/forgejo/pulls/1433 - This XSS allows for `href`s in anchor elements to be set to a `javascript:` uri in the repository description, which would upon clicking (and not upon loading) the anchor element execute the specified javascript in that uri. - [`AllowStandardURLs`](https://pkg.go.dev/github.com/microcosm-cc/bluemonday#Policy.AllowStandardURLs) is now called for the repository description policy, which ensures that URIs in anchor elements are `mailto:`, `http://` or `https://` and thereby disallowing the `javascript:` URI. It also now allows non-relative links and sets `rel="nofollow"` on anchor elements. - Unit test added.
235 lines
9.2 KiB
Go
235 lines
9.2 KiB
Go
// Copyright 2017 The Gitea Authors. All rights reserved.
|
|
// Copyright 2017 The Gogs Authors. All rights reserved.
|
|
// SPDX-License-Identifier: MIT
|
|
|
|
package markup
|
|
|
|
import (
|
|
"io"
|
|
"net/url"
|
|
"regexp"
|
|
"sync"
|
|
|
|
"code.gitea.io/gitea/modules/setting"
|
|
|
|
"github.com/microcosm-cc/bluemonday"
|
|
)
|
|
|
|
// Sanitizer is a protection wrapper of *bluemonday.Policy which does not allow
|
|
// any modification to the underlying policies once it's been created.
|
|
type Sanitizer struct {
|
|
defaultPolicy *bluemonday.Policy
|
|
descriptionPolicy *bluemonday.Policy
|
|
rendererPolicies map[string]*bluemonday.Policy
|
|
init sync.Once
|
|
}
|
|
|
|
var (
|
|
sanitizer = &Sanitizer{}
|
|
allowAllRegex = regexp.MustCompile(".+")
|
|
)
|
|
|
|
// NewSanitizer initializes sanitizer with allowed attributes based on settings.
|
|
// Multiple calls to this function will only create one instance of Sanitizer during
|
|
// entire application lifecycle.
|
|
func NewSanitizer() {
|
|
sanitizer.init.Do(func() {
|
|
InitializeSanitizer()
|
|
})
|
|
}
|
|
|
|
// InitializeSanitizer (re)initializes the current sanitizer to account for changes in settings
|
|
func InitializeSanitizer() {
|
|
sanitizer.rendererPolicies = map[string]*bluemonday.Policy{}
|
|
sanitizer.defaultPolicy = createDefaultPolicy()
|
|
sanitizer.descriptionPolicy = createRepoDescriptionPolicy()
|
|
|
|
for name, renderer := range renderers {
|
|
sanitizerRules := renderer.SanitizerRules()
|
|
if len(sanitizerRules) > 0 {
|
|
policy := createDefaultPolicy()
|
|
addSanitizerRules(policy, sanitizerRules)
|
|
sanitizer.rendererPolicies[name] = policy
|
|
}
|
|
}
|
|
}
|
|
|
|
func createDefaultPolicy() *bluemonday.Policy {
|
|
policy := bluemonday.UGCPolicy()
|
|
|
|
// For JS code copy and Mermaid loading state
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^code-block( is-loading)?$`)).OnElements("pre")
|
|
|
|
// For color preview
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^color-preview$`)).OnElements("span")
|
|
|
|
// For attention
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^attention-title$`)).OnElements("p")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^attention-header attention-\w+$`)).OnElements("blockquote")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^attention-\w+$`)).OnElements("strong")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^attention-icon attention-\w+ svg octicon-[\w-]+$`)).OnElements("svg")
|
|
policy.AllowAttrs("viewBox", "width", "height", "aria-hidden").OnElements("svg")
|
|
policy.AllowAttrs("fill-rule", "d").OnElements("path")
|
|
|
|
// For Chroma markdown plugin
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^(chroma )?language-[\w-]+( display)?( is-loading)?$`)).OnElements("code")
|
|
|
|
// Checkboxes
|
|
policy.AllowAttrs("type").Matching(regexp.MustCompile(`^checkbox$`)).OnElements("input")
|
|
policy.AllowAttrs("checked", "disabled", "data-source-position").OnElements("input")
|
|
|
|
// Custom URL-Schemes
|
|
if len(setting.Markdown.CustomURLSchemes) > 0 {
|
|
policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
|
|
} else {
|
|
policy.AllowURLSchemesMatching(allowAllRegex)
|
|
|
|
// Even if every scheme is allowed, these three are blocked for security reasons
|
|
disallowScheme := func(*url.URL) bool {
|
|
return false
|
|
}
|
|
policy.AllowURLSchemeWithCustomPolicy("javascript", disallowScheme)
|
|
policy.AllowURLSchemeWithCustomPolicy("vbscript", disallowScheme)
|
|
policy.AllowURLSchemeWithCustomPolicy("data", disallowScheme)
|
|
}
|
|
|
|
// Allow classes for anchors
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`ref-issue( ref-external-issue)?`)).OnElements("a")
|
|
|
|
// Allow classes for task lists
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`task-list-item`)).OnElements("li")
|
|
|
|
// Allow classes for org mode list item status.
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^(unchecked|checked|indeterminate)$`)).OnElements("li")
|
|
|
|
// Allow icons
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^icon(\s+[\p{L}\p{N}_-]+)+$`)).OnElements("i")
|
|
|
|
// Allow classes for emojis
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`emoji`)).OnElements("img")
|
|
|
|
// Allow icons, emojis, chroma syntax and keyword markup on span
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^((icon(\s+[\p{L}\p{N}_-]+)+)|(emoji)|(language-math display)|(language-math inline))$|^([a-z][a-z0-9]{0,2})$|^` + keywordClass + `$`)).OnElements("span")
|
|
|
|
// Allow 'color' and 'background-color' properties for the style attribute on text elements and table cells.
|
|
policy.AllowStyles("color", "background-color").OnElements("span", "p", "th", "td")
|
|
|
|
// Allow classes for file preview links...
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^(lines-num|lines-code chroma)$")).OnElements("td")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^code-inner$")).OnElements("code")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^file-preview-box$")).OnElements("div")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^ui table$")).OnElements("div")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^header$")).OnElements("div")
|
|
policy.AllowAttrs("data-line-number").Matching(regexp.MustCompile("^[0-9]+$")).OnElements("span")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^text small grey$")).OnElements("span")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^file-preview*")).OnElements("table")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^lines-escape$")).OnElements("td")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^toggle-escape-button btn interact-bg$")).OnElements("button")
|
|
policy.AllowAttrs("title").OnElements("button")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^ambiguous-code-point$")).OnElements("span")
|
|
policy.AllowAttrs("data-tooltip-content").OnElements("span")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("muted|(text black)")).OnElements("a")
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile("^ui warning message tw-text-left$")).OnElements("div")
|
|
|
|
// Allow generally safe attributes
|
|
generalSafeAttrs := []string{
|
|
"abbr", "accept", "accept-charset",
|
|
"accesskey", "action", "align", "alt",
|
|
"aria-describedby", "aria-hidden", "aria-label", "aria-labelledby",
|
|
"axis", "border", "cellpadding", "cellspacing", "char",
|
|
"charoff", "charset", "checked",
|
|
"clear", "cols", "colspan", "color",
|
|
"compact", "coords", "datetime", "dir",
|
|
"disabled", "enctype", "for", "frame",
|
|
"headers", "height", "hreflang",
|
|
"hspace", "ismap", "label", "lang",
|
|
"maxlength", "media", "method",
|
|
"multiple", "name", "nohref", "noshade",
|
|
"nowrap", "open", "prompt", "readonly", "rel", "rev",
|
|
"rows", "rowspan", "rules", "scope",
|
|
"selected", "shape", "size", "span",
|
|
"start", "summary", "tabindex", "target",
|
|
"title", "type", "usemap", "valign", "value",
|
|
"vspace", "width", "itemprop",
|
|
}
|
|
|
|
generalSafeElements := []string{
|
|
"h1", "h2", "h3", "h4", "h5", "h6", "h7", "h8", "br", "b", "i", "strong", "em", "a", "pre", "code", "img", "tt",
|
|
"div", "ins", "del", "sup", "sub", "p", "ol", "ul", "table", "thead", "tbody", "tfoot", "blockquote", "label",
|
|
"dl", "dt", "dd", "kbd", "q", "samp", "var", "hr", "ruby", "rt", "rp", "li", "tr", "td", "th", "s", "strike", "summary",
|
|
"details", "caption", "figure", "figcaption",
|
|
"abbr", "bdo", "cite", "dfn", "mark", "small", "span", "time", "video", "wbr",
|
|
}
|
|
|
|
policy.AllowAttrs(generalSafeAttrs...).OnElements(generalSafeElements...)
|
|
|
|
policy.AllowAttrs("src", "autoplay", "controls").OnElements("video")
|
|
|
|
policy.AllowAttrs("itemscope", "itemtype").OnElements("div")
|
|
|
|
// FIXME: Need to handle longdesc in img but there is no easy way to do it
|
|
|
|
// Custom keyword markup
|
|
addSanitizerRules(policy, setting.ExternalSanitizerRules)
|
|
|
|
return policy
|
|
}
|
|
|
|
// createRepoDescriptionPolicy returns a minimal more strict policy that is used for
|
|
// repository descriptions.
|
|
func createRepoDescriptionPolicy() *bluemonday.Policy {
|
|
policy := bluemonday.NewPolicy()
|
|
policy.AllowStandardURLs()
|
|
|
|
// Allow italics and bold.
|
|
policy.AllowElements("i", "b", "em", "strong")
|
|
|
|
// Allow code.
|
|
policy.AllowElements("code")
|
|
|
|
// Allow links
|
|
policy.AllowAttrs("href", "target", "rel").OnElements("a")
|
|
|
|
// Allow classes for emojis
|
|
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^emoji$`)).OnElements("img", "span")
|
|
policy.AllowAttrs("aria-label").OnElements("span")
|
|
|
|
return policy
|
|
}
|
|
|
|
func addSanitizerRules(policy *bluemonday.Policy, rules []setting.MarkupSanitizerRule) {
|
|
for _, rule := range rules {
|
|
if rule.AllowDataURIImages {
|
|
policy.AllowDataURIImages()
|
|
}
|
|
if rule.Element != "" {
|
|
if rule.Regexp != nil {
|
|
policy.AllowAttrs(rule.AllowAttr).Matching(rule.Regexp).OnElements(rule.Element)
|
|
} else {
|
|
policy.AllowAttrs(rule.AllowAttr).OnElements(rule.Element)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// SanitizeDescription sanitizes the HTML generated for a repository description.
|
|
func SanitizeDescription(s string) string {
|
|
NewSanitizer()
|
|
return sanitizer.descriptionPolicy.Sanitize(s)
|
|
}
|
|
|
|
// Sanitize takes a string that contains a HTML fragment or document and applies policy whitelist.
|
|
func Sanitize(s string) string {
|
|
NewSanitizer()
|
|
return sanitizer.defaultPolicy.Sanitize(s)
|
|
}
|
|
|
|
// SanitizeReader sanitizes a Reader
|
|
func SanitizeReader(r io.Reader, renderer string, w io.Writer) error {
|
|
NewSanitizer()
|
|
policy, exist := sanitizer.rendererPolicies[renderer]
|
|
if !exist {
|
|
policy = sanitizer.defaultPolicy
|
|
}
|
|
return policy.SanitizeReaderToWriter(r, w)
|
|
}
|