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Add sanitizer rules per renderer (#16110)

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* Added sanitizer rules per renderer.

* Updated documentation.

Co-authored-by: techknowlogick <techknowlogick@gitea.io>
This commit is contained in:
KN4CK3R
2021-06-23 23:09:51 +02:00
committed by GitHub
parent eb324a9402
commit c9c7afda1a
10 changed files with 215 additions and 113 deletions
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88
modules/markup/sanitizer.go
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@@ -19,8 +19,9 @@ import (
// 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 {
policy *bluemonday.Policy
init sync.Once
defaultPolicy *bluemonday.Policy
rendererPolicies map[string]*bluemonday.Policy
init sync.Once
}
var sanitizer = &Sanitizer{}
@@ -30,47 +31,57 @@ var sanitizer = &Sanitizer{}
// entire application lifecycle.
func NewSanitizer() {
sanitizer.init.Do(func() {
ReplaceSanitizer()
InitializeSanitizer()
})
}
// ReplaceSanitizer replaces the current sanitizer to account for changes in settings
func ReplaceSanitizer() {
sanitizer.policy = bluemonday.UGCPolicy()
// InitializeSanitizer (re)initializes the current sanitizer to account for changes in settings
func InitializeSanitizer() {
sanitizer.rendererPolicies = map[string]*bluemonday.Policy{}
sanitizer.defaultPolicy = createDefaultPolicy()
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 Chroma markdown plugin
sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^is-loading$`)).OnElements("pre")
sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^(chroma )?language-[\w-]+$`)).OnElements("code")
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^is-loading$`)).OnElements("pre")
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^(chroma )?language-[\w-]+$`)).OnElements("code")
// Checkboxes
sanitizer.policy.AllowAttrs("type").Matching(regexp.MustCompile(`^checkbox$`)).OnElements("input")
sanitizer.policy.AllowAttrs("checked", "disabled", "data-source-position").OnElements("input")
policy.AllowAttrs("type").Matching(regexp.MustCompile(`^checkbox$`)).OnElements("input")
policy.AllowAttrs("checked", "disabled", "data-source-position").OnElements("input")
// Custom URL-Schemes
if len(setting.Markdown.CustomURLSchemes) > 0 {
sanitizer.policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
}
// Allow classes for anchors
sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`ref-issue`)).OnElements("a")
policy.AllowAttrs("class").Matching(regexp.MustCompile(`ref-issue`)).OnElements("a")
// Allow classes for task lists
sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`task-list-item`)).OnElements("li")
policy.AllowAttrs("class").Matching(regexp.MustCompile(`task-list-item`)).OnElements("li")
// Allow icons
sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^icon(\s+[\p{L}\p{N}_-]+)+$`)).OnElements("i")
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^icon(\s+[\p{L}\p{N}_-]+)+$`)).OnElements("i")
// Allow unlabelled labels
sanitizer.policy.AllowNoAttrs().OnElements("label")
policy.AllowNoAttrs().OnElements("label")
// Allow classes for emojis
sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`emoji`)).OnElements("img")
policy.AllowAttrs("class").Matching(regexp.MustCompile(`emoji`)).OnElements("img")
// Allow icons, emojis, chroma syntax and keyword markup on span
sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^((icon(\s+[\p{L}\p{N}_-]+)+)|(emoji))$|^([a-z][a-z0-9]{0,2})$|^` + keywordClass + `$`)).OnElements("span")
// Allow data tables
sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`data-table`)).OnElements("table")
sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`line-num`)).OnElements("th", "td")
policy.AllowAttrs("class").Matching(regexp.MustCompile(`^((icon(\s+[\p{L}\p{N}_-]+)+)|(emoji))$|^([a-z][a-z0-9]{0,2})$|^` + keywordClass + `$`)).OnElements("span")
// Allow generally safe attributes
generalSafeAttrs := []string{"abbr", "accept", "accept-charset",
@@ -101,18 +112,29 @@ func ReplaceSanitizer() {
"abbr", "bdo", "cite", "dfn", "mark", "small", "span", "time", "wbr",
}
sanitizer.policy.AllowAttrs(generalSafeAttrs...).OnElements(generalSafeElements...)
policy.AllowAttrs(generalSafeAttrs...).OnElements(generalSafeElements...)
sanitizer.policy.AllowAttrs("itemscope", "itemtype").OnElements("div")
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
for _, rule := range setting.ExternalSanitizerRules {
if rule.Regexp != nil {
sanitizer.policy.AllowAttrs(rule.AllowAttr).Matching(rule.Regexp).OnElements(rule.Element)
} else {
sanitizer.policy.AllowAttrs(rule.AllowAttr).OnElements(rule.Element)
addSanitizerRules(policy, setting.ExternalSanitizerRules)
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)
}
}
}
}
@@ -120,11 +142,15 @@ func ReplaceSanitizer() {
// Sanitize takes a string that contains a HTML fragment or document and applies policy whitelist.
func Sanitize(s string) string {
NewSanitizer()
return sanitizer.policy.Sanitize(s)
return sanitizer.defaultPolicy.Sanitize(s)
}
// SanitizeReader sanitizes a Reader
func SanitizeReader(r io.Reader) *bytes.Buffer {
func SanitizeReader(r io.Reader, renderer string) *bytes.Buffer {
NewSanitizer()
return sanitizer.policy.SanitizeReader(r)
policy, exist := sanitizer.rendererPolicies[renderer]
if !exist {
policy = sanitizer.defaultPolicy
}
return policy.SanitizeReader(r)
}