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[bugfix] Use custom bluemonday policy to disallow inline img tags (#2100)

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tobi 2023-08-11 14:40:11 +02:00 committed by GitHub
parent 3aedd937c3
commit dc96562b40
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17 changed files with 243 additions and 78 deletions
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30
internal/ap/normalize.go
View File

@ -20,6 +20,7 @@ package ap
import (
"github.com/superseriousbusiness/activity/pub"
"github.com/superseriousbusiness/activity/streams"
"github.com/superseriousbusiness/gotosocial/internal/text"
)
/*
@ -126,7 +127,8 @@ func NormalizeIncomingActivityObject(activity pub.Activity, rawJSON map[string]i
}
// NormalizeIncomingContent replaces the Content of the given item
// with the raw 'content' value from the raw json object map.
// with the sanitized version of the raw 'content' value from the
// raw json object map.
//
// noop if there was no content in the json object map or the
// content was not a plain string.
@ -145,6 +147,14 @@ func NormalizeIncomingContent(item WithSetContent, rawJSON map[string]interface{
return
}
// Content should be HTML encoded by default:
// https://www.w3.org/TR/activitystreams-vocabulary/#dfn-content
//
// TODO: sanitize differently based on mediaType.
// https://www.w3.org/TR/activitystreams-vocabulary/#dfn-mediatype
content = text.SanitizeToHTML(content)
content = text.MinifyHTML(content)
// Set normalized content property from the raw string;
// this replaces any existing content property on the item.
contentProp := streams.NewActivityStreamsContentProperty()
@ -154,7 +164,8 @@ func NormalizeIncomingContent(item WithSetContent, rawJSON map[string]interface{
// NormalizeIncomingAttachments normalizes all attachments (if any) of the given
// item, replacing the 'name' (aka content warning) field of each attachment
// with the raw 'name' value from the raw json object map.
// with the raw 'name' value from the raw json object map, and doing sanitization
// on the result.
//
// noop if there are no attachments; noop if attachment is not a format
// we can understand.
@ -212,7 +223,8 @@ func NormalizeIncomingAttachments(item WithAttachment, rawJSON map[string]interf
}
// NormalizeIncomingSummary replaces the Summary of the given item
// with the raw 'summary' value from the raw json object map.
// with the sanitized version of the raw 'summary' value from the
// raw json object map.
//
// noop if there was no summary in the json object map or the
// summary was not a plain string.
@ -229,6 +241,11 @@ func NormalizeIncomingSummary(item WithSetSummary, rawJSON map[string]interface{
return
}
// Summary should be HTML encoded:
// https://www.w3.org/TR/activitystreams-vocabulary/#dfn-summary
summary = text.SanitizeToHTML(summary)
summary = text.MinifyHTML(summary)
// Set normalized summary property from the raw string; this
// will replace any existing summary property on the item.
summaryProp := streams.NewActivityStreamsSummaryProperty()
@ -254,6 +271,13 @@ func NormalizeIncomingName(item WithSetName, rawJSON map[string]interface{}) {
return
}
// Name *must not* include any HTML markup:
// https://www.w3.org/TR/activitystreams-vocabulary/#dfn-name
//
// todo: We probably want to update this to allow
// *escaped* HTML markup, but for now just nuke it.
name = text.SanitizeToPlaintext(name)
// Set normalized name property from the raw string; this
// will replace any existing name property on the item.
nameProp := streams.NewActivityStreamsNameProperty()

16
internal/ap/normalize_test.go
View File

@ -146,7 +146,7 @@ func (suite *NormalizeTestSuite) getStatusableWithMultipleAttachments() (vocab.A
"type": "Document",
"mediaType": "image/jpeg",
"url": "https://files.example.org/media_attachments/files/110/258/459/579/509/026/original/b65392ebe0fb04ef.jpeg",
"name": "danger: #cute but will claw you :("
"name": "image of a cat & there's a note saying: <danger: #cute but will claw you :(>"
}
]
}`)
@ -192,7 +192,7 @@ func (suite *NormalizeTestSuite) TestNormalizeActivityObject() {
)
ap.NormalizeIncomingActivityObject(create, map[string]interface{}{"object": rawNote})
suite.Equal(`UPDATE: As of this morning there are now more than 7 million Mastodon users, most from the <a class="hashtag" data-tag="twittermigration" href="https://example.org/tag/twittermigration" rel="tag ugc">#TwitterMigration</a>.<br><br>In fact, 100,000 new accounts have been created since last night.<br><br>Since last night&#39;s spike 8,000-12,000 new accounts are being created every hour.<br><br>Yesterday, I estimated that Mastodon would have 8 million users by the end of the week. That might happen a lot sooner if this trend continues.`, ap.ExtractContent(note))
suite.Equal(`UPDATE: As of this morning there are now more than 7 million Mastodon users, most from the <a class="hashtag" href="https://example.org/tag/twittermigration" rel="tag ugc nofollow noreferrer noopener" target="_blank">#TwitterMigration</a>.<br><br>In fact, 100,000 new accounts have been created since last night.<br><br>Since last night's spike 8,000-12,000 new accounts are being created every hour.<br><br>Yesterday, I estimated that Mastodon would have 8 million users by the end of the week. That might happen a lot sooner if this trend continues.`, ap.ExtractContent(note))
}
func (suite *NormalizeTestSuite) TestNormalizeStatusableAttachmentsOneAttachment() {
@ -224,7 +224,7 @@ func (suite *NormalizeTestSuite) TestNormalizeStatusableAttachmentsOneAttachment
"@context": "https://www.w3.org/ns/activitystreams",
"attachment": {
"mediaType": "image/jpeg",
"name": "DESCRIPTION: here's \u003c\u003ca\u003e\u003e picture of a #cat, it's cute! here's some special characters: \"\" \\ weeee''''",
"name": "DESCRIPTION: here's \u003c\u003e picture of a #cat, it's cute! here's some special characters: \"\" \\ weeee''''",
"type": "Document",
"url": "https://files.example.org/media_attachments/files/110/258/459/579/509/026/original/b65392ebe0fb04ef.jpeg"
},
@ -265,7 +265,7 @@ func (suite *NormalizeTestSuite) TestNormalizeStatusableAttachmentsOneAttachment
"@context": "https://www.w3.org/ns/activitystreams",
"attachment": {
"mediaType": "image/jpeg",
"name": "DESCRIPTION: here's \u003c\u003ca\u003e\u003e picture of a #cat, it's cute! here's some special characters: \"\" \\ weeee''''",
"name": "DESCRIPTION: here's \u003c\u003e picture of a #cat, it's cute! here's some special characters: \"\" \\ weeee''''",
"type": "Document",
"url": "https://files.example.org/media_attachments/files/110/258/459/579/509/026/original/b65392ebe0fb04ef.jpeg"
},
@ -304,7 +304,7 @@ func (suite *NormalizeTestSuite) TestNormalizeStatusableAttachmentsMultipleAttac
},
{
"mediaType": "image/jpeg",
"name": "danger: #cute%20but%20will%20claw%20you%20:(",
"name": "image of a cat \u0026amp; there's a note saying: \u0026lt;danger: #cute but will claw you :(\u0026gt;",
"type": "Document",
"url": "https://files.example.org/media_attachments/files/110/258/459/579/509/026/original/b65392ebe0fb04ef.jpeg"
}
@ -326,7 +326,7 @@ func (suite *NormalizeTestSuite) TestNormalizeStatusableAttachmentsMultipleAttac
"attachment": [
{
"mediaType": "image/jpeg",
"name": "DESCRIPTION: here's \u003c\u003ca\u003e\u003e picture of a #cat, it's cute! here's some special characters: \"\" \\ weeee''''",
"name": "DESCRIPTION: here's \u003c\u003e picture of a #cat, it's cute! here's some special characters: \"\" \\ weeee''''",
"type": "Document",
"url": "https://files.example.org/media_attachments/files/110/258/459/579/509/026/original/b65392ebe0fb04ef.jpeg"
},
@ -343,7 +343,7 @@ func (suite *NormalizeTestSuite) TestNormalizeStatusableAttachmentsMultipleAttac
},
{
"mediaType": "image/jpeg",
"name": "danger: #cute but will claw you :(",
"name": "image of a cat \u0026 there's a note saying:",
"type": "Document",
"url": "https://files.example.org/media_attachments/files/110/258/459/579/509/026/original/b65392ebe0fb04ef.jpeg"
}
@ -380,7 +380,7 @@ func (suite *NormalizeTestSuite) TestNormalizeStatusableSummary() {
suite.Equal(`warning: #WEIRD%20%23SUMMARY%20;;;;a;;a;asv%20%20%20%20khop8273987(*%5E&%5E)`, ap.ExtractSummary(statusable))
ap.NormalizeIncomingSummary(statusable, rawAccount)
suite.Equal(`warning: #WEIRD #SUMMARY ;;;;a;;a;asv khop8273987(*^&^)`, ap.ExtractSummary(statusable))
suite.Equal(`warning: #WEIRD #SUMMARY ;;;;a;;a;asv khop8273987(*^&^)`, ap.ExtractSummary(statusable))
}
func (suite *NormalizeTestSuite) TestNormalizeStatusableName() {

2
internal/api/client/statuses/statuscreate_test.go
View File

@ -43,7 +43,7 @@ type StatusCreateTestSuite struct {
const (
statusWithLinksAndTags = "#test alright, should be able to post #links with fragments in them now, let's see........\n\nhttps://docs.gotosocial.org/en/latest/user_guide/posts/#links\n\n#gotosocial\n\n(tobi remember to pull the docker image challenge)"
statusMarkdown = "# Title\n\n## Smaller title\n\nThis is a post written in [markdown](https://www.markdownguide.org/)\n\n<img src=\"https://d33wubrfki0l68.cloudfront.net/f1f475a6fda1c2c4be4cac04033db5c3293032b4/513a4/assets/images/markdown-mark-white.svg\"/>"
statusMarkdownExpected = "<h1>Title</h1><h2>Smaller title</h2><p>This is a post written in <a href=\"https://www.markdownguide.org/\" rel=\"nofollow noreferrer noopener\" target=\"_blank\">markdown</a></p><img src=\"https://d33wubrfki0l68.cloudfront.net/f1f475a6fda1c2c4be4cac04033db5c3293032b4/513a4/assets/images/markdown-mark-white.svg\" crossorigin=\"anonymous\">"
statusMarkdownExpected = "<h1>Title</h1><h2>Smaller title</h2><p>This is a post written in <a href=\"https://www.markdownguide.org/\" rel=\"nofollow noreferrer noopener\" target=\"_blank\">markdown</a></p>"
)
// Post a new status with some custom visibility settings

2
internal/processing/account/create.go
View File

@ -71,7 +71,7 @@ func (p *Processor) Create(
Username: form.Username,
Email: form.Email,
Password: form.Password,
Reason: text.SanitizePlaintext(reason),
Reason: text.SanitizeToPlaintext(reason),
PreApproved: !config.GetAccountsApprovalRequired(), // Mark as approved if no approval required.
SignUpIP: form.IP,
Locale: form.Locale,

8
internal/processing/account/update.go
View File

@ -67,7 +67,7 @@ func (p *Processor) Update(ctx context.Context, account *gtsmodel.Account, form
}
// Parse new display name (always from plaintext).
account.DisplayName = text.SanitizePlaintext(displayName)
account.DisplayName = text.SanitizeToPlaintext(displayName)
// If display name has changed, account emojis may have also changed.
emojisChanged = true
@ -110,8 +110,8 @@ func (p *Processor) Update(ctx context.Context, account *gtsmodel.Account, form
// Sanitize raw field values.
fieldRaw := &gtsmodel.Field{
Name: text.SanitizePlaintext(name),
Value: text.SanitizePlaintext(value),
Name: text.SanitizeToPlaintext(name),
Value: text.SanitizeToPlaintext(value),
}
fieldsRaw = append(fieldsRaw, fieldRaw)
}
@ -255,7 +255,7 @@ func (p *Processor) Update(ctx context.Context, account *gtsmodel.Account, form
if err := validate.CustomCSS(customCSS); err != nil {
return nil, gtserror.NewErrorBadRequest(err, err.Error())
}
account.CustomCSS = text.SanitizePlaintext(customCSS)
account.CustomCSS = text.SanitizeToPlaintext(customCSS)
}
if form.EnableRSS != nil {

4
internal/processing/admin/domainblock.go
View File

@ -67,8 +67,8 @@ func (p *Processor) DomainBlockCreate(
ID: id.NewULID(),
Domain: domain,
CreatedByAccountID: account.ID,
PrivateComment: text.SanitizePlaintext(privateComment),
PublicComment: text.SanitizePlaintext(publicComment),
PrivateComment: text.SanitizeToPlaintext(privateComment),
PublicComment: text.SanitizeToPlaintext(publicComment),
Obfuscate: &obfuscate,
SubscriptionID: subscriptionID,
}

8
internal/processing/instance.go
View File

@ -159,7 +159,7 @@ func (p *Processor) InstancePatch(ctx context.Context, form *apimodel.InstanceSe
return nil, gtserror.NewErrorBadRequest(err, fmt.Sprintf("site title invalid: %s", err))
}
updatingColumns = append(updatingColumns, "title")
instance.Title = text.SanitizePlaintext(*form.Title) // don't allow html in site title
instance.Title = text.SanitizeToPlaintext(*form.Title) // don't allow html in site title
}
// validate & update site contact account if it's set on the form
@ -215,7 +215,7 @@ func (p *Processor) InstancePatch(ctx context.Context, form *apimodel.InstanceSe
return nil, gtserror.NewErrorBadRequest(err, err.Error())
}
updatingColumns = append(updatingColumns, "short_description")
instance.ShortDescription = text.SanitizeHTML(*form.ShortDescription) // html is OK in site description, but we should sanitize it
instance.ShortDescription = text.SanitizeToHTML(*form.ShortDescription) // html is OK in site description, but we should sanitize it
}
// validate & update site description if it's set on the form
@ -224,7 +224,7 @@ func (p *Processor) InstancePatch(ctx context.Context, form *apimodel.InstanceSe
return nil, gtserror.NewErrorBadRequest(err, err.Error())
}
updatingColumns = append(updatingColumns, "description")
instance.Description = text.SanitizeHTML(*form.Description) // html is OK in site description, but we should sanitize it
instance.Description = text.SanitizeToHTML(*form.Description) // html is OK in site description, but we should sanitize it
}
// validate & update site terms if it's set on the form
@ -233,7 +233,7 @@ func (p *Processor) InstancePatch(ctx context.Context, form *apimodel.InstanceSe
return nil, gtserror.NewErrorBadRequest(err, err.Error())
}
updatingColumns = append(updatingColumns, "terms")
instance.Terms = text.SanitizeHTML(*form.Terms) // html is OK in site terms, but we should sanitize it
instance.Terms = text.SanitizeToHTML(*form.Terms) // html is OK in site terms, but we should sanitize it
}
var updateInstanceAccount bool

2
internal/processing/media/update.go
View File

@ -47,7 +47,7 @@ func (p *Processor) Update(ctx context.Context, account *gtsmodel.Account, media
var updatingColumns []string
if form.Description != nil {
attachment.Description = text.SanitizePlaintext(*form.Description)
attachment.Description = text.SanitizeToPlaintext(*form.Description)
updatingColumns = append(updatingColumns, "description")
}

2
internal/processing/status/create.go
View File

@ -54,7 +54,7 @@ func (p *Processor) Create(ctx context.Context, account *gtsmodel.Account, appli
Local: &local,
AccountID: account.ID,
AccountURI: account.URI,
ContentWarning: text.SanitizePlaintext(form.SpoilerText),
ContentWarning: text.SanitizeToPlaintext(form.SpoilerText),
ActivityStreamsType: ap.ObjectNote,
Sensitive: &sensitive,
CreatedWithApplicationID: application.ID,

7
internal/text/emojionly.go
View File

@ -61,13 +61,10 @@ func (f *formatter) FromPlainEmojiOnly(ctx context.Context, pmf gtsmodel.ParseMe
result.HTML = htmlContentBytes.String()
// clean anything dangerous out of the HTML
result.HTML = SanitizeHTML(result.HTML)
result.HTML = SanitizeToHTML(result.HTML)
// shrink ray
result.HTML, err = m.String("text/html", result.HTML)
if err != nil {
log.Errorf(ctx, "error minifying HTML: %s", err)
}
result.HTML = MinifyHTML(result.HTML)
return result
}

7
internal/text/markdown.go
View File

@ -57,13 +57,10 @@ func (f *formatter) FromMarkdown(ctx context.Context, pmf gtsmodel.ParseMentionF
result.HTML = htmlContentBytes.String()
// clean anything dangerous out of the HTML
result.HTML = SanitizeHTML(result.HTML)
result.HTML = SanitizeToHTML(result.HTML)
// shrink ray
result.HTML, err = m.String("text/html", result.HTML)
if err != nil {
log.Errorf(ctx, "error minifying HTML: %s", err)
}
result.HTML = MinifyHTML(result.HTML)
return result
}

2
internal/text/markdown_test.go
View File

@ -51,7 +51,7 @@ const (
withHashtag = "# Title\n\nhere's a simple status that uses hashtag #Hashtag!"
withHashtagExpected = "<h1>Title</h1><p>here's a simple status that uses hashtag <a href=\"http://localhost:8080/tags/hashtag\" class=\"mention hashtag\" rel=\"tag nofollow noreferrer noopener\" target=\"_blank\">#<span>Hashtag</span></a>!</p>"
mdWithHTML = "# Title\n\nHere's a simple text in markdown.\n\nHere's a <a href=\"https://example.org\">link</a>.\n\nHere's an image: <img src=\"https://gts.superseriousbusiness.org/assets/logo.png\" alt=\"The GoToSocial sloth logo.\" width=\"500\" height=\"600\">"
mdWithHTMLExpected = "<h1>Title</h1><p>Here's a simple text in markdown.</p><p>Here's a <a href=\"https://example.org\" rel=\"nofollow noreferrer noopener\" target=\"_blank\">link</a>.</p><p>Here's an image: <img src=\"https://gts.superseriousbusiness.org/assets/logo.png\" alt=\"The GoToSocial sloth logo.\" width=\"500\" height=\"600\" crossorigin=\"anonymous\"></p>"
mdWithHTMLExpected = "<h1>Title</h1><p>Here's a simple text in markdown.</p><p>Here's a <a href=\"https://example.org\" rel=\"nofollow noreferrer noopener\" target=\"_blank\">link</a>.</p><p>Here's an image:</p>"
mdWithCheekyHTML = "# Title\n\nHere's a simple text in markdown.\n\nHere's a cheeky little script: <script>alert(ahhhh)</script>"
mdWithCheekyHTMLExpected = "<h1>Title</h1><p>Here's a simple text in markdown.</p><p>Here's a cheeky little script:</p>"
mdWithHashtagInitial = "#welcome #Hashtag"

21
internal/text/minify.go
View File

@ -18,6 +18,7 @@
package text
import (
"github.com/superseriousbusiness/gotosocial/internal/log"
"github.com/tdewolff/minify/v2"
"github.com/tdewolff/minify/v2/html"
)
@ -31,3 +32,23 @@ var m = func() *minify.M {
})
return m
}()
// MinifyHTML minifies the given string
// under the assumption that it's HTML.
//
// If input is not HTML encoded, this
// function will try to do minimization
// anyway, but this may produce unexpected
// results.
//
// If an error occurs during minimization,
// it will be logged and the original string
// returned unmodified.
func MinifyHTML(in string) string {
out, err := m.String("text/html", in)
if err != nil {
log.Error(nil, err)
}
return out
}

7
internal/text/plain.go
View File

@ -65,13 +65,10 @@ func (f *formatter) fromPlain(
result.HTML = htmlContentBytes.String()
// Clean anything dangerous out of resulting HTML.
result.HTML = SanitizeHTML(result.HTML)
result.HTML = SanitizeToHTML(result.HTML)
// Shrink ray!
var err error
if result.HTML, err = m.String("text/html", result.HTML); err != nil {
log.Errorf(ctx, "error minifying HTML: %s", err)
}
result.HTML = MinifyHTML(result.HTML)
return result
}

171
internal/text/sanitize.go
View File

@ -25,44 +25,167 @@ import (
"github.com/microcosm-cc/bluemonday"
)
// '[A]llows a broad selection of HTML elements and attributes that are safe for user generated content.
// Note that this policy does not allow iframes, object, embed, styles, script, etc.
// An example usage scenario would be blog post bodies where a variety of formatting is expected along with the potential for TABLEs and IMGs.'
//
// Source: https://github.com/microcosm-cc/bluemonday#usage
var regular *bluemonday.Policy = bluemonday.UGCPolicy().
RequireNoReferrerOnLinks(true).
RequireNoFollowOnLinks(false). // remove the global default which adds rel="nofollow" to all links including local relative
RequireNoFollowOnFullyQualifiedLinks(true). // add rel="nofollow" on all external links
RequireCrossOriginAnonymous(true).
AddTargetBlankToFullyQualifiedLinks(true).
AllowAttrs("class", "href", "rel").OnElements("a").
AllowAttrs("class").OnElements("span").
AllowAttrs("class").Matching(regexp.MustCompile("^language-[a-zA-Z0-9]+$")).OnElements("code").
SkipElementsContent("code", "pre")
// Regular HTML policy is an adapted version of the default
// bluemonday UGC policy, with some tweaks of our own.
// See: https://github.com/microcosm-cc/bluemonday#usage
var regular *bluemonday.Policy = func() *bluemonday.Policy {
p := bluemonday.NewPolicy()
// '[C]an be thought of as equivalent to stripping all HTML elements and their attributes as it has nothing on its allowlist.
// An example usage scenario would be blog post titles where HTML tags are not expected at all
// and if they are then the elements and the content of the elements should be stripped. This is a very strict policy.'
// AllowStandardAttributes will enable "id", "title" and
// the language specific attributes "dir" and "lang" on
// all elements that are allowed
p.AllowStandardAttributes()
/*
LAYOUT AND FORMATTING
*/
// "aside" is permitted and takes no attributes.
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/aside
p.AllowElements("article", "aside")
// "details" is permitted, including the "open" attribute
// which can either be blank or the value "open".
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/details
p.AllowAttrs("open").Matching(regexp.MustCompile(`(?i)^(|open)$`)).OnElements("details")
// "section" is permitted and takes no attributes.
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/section
p.AllowElements("section")
// "summary" is permitted and takes no attributes.
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/summary
p.AllowElements("summary")
// "h1" through "h6" are permitted and take no attributes.
p.AllowElements("h1", "h2", "h3", "h4", "h5", "h6")
// "hgroup" is permitted and takes no attributes.
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/hgroup
p.AllowElements("hgroup")
// "blockquote" is permitted, including the "cite"
// attribute which must be a standard URL.
p.AllowAttrs("cite").OnElements("blockquote")
// "br" "div" "hr" "p" "span" "wbr" are permitted and take no attributes
p.AllowElements("br", "div", "hr", "p", "span", "wbr")
// The following are all inline phrasing elements:
p.AllowElements("abbr", "acronym", "cite", "code", "dfn", "em",
"figcaption", "mark", "s", "samp", "strong", "sub", "sup", "var")
// "q" is permitted and "cite" is a URL and handled by URL policies
p.AllowAttrs("cite").OnElements("q")
// "time" is permitted
p.AllowAttrs("datetime").Matching(bluemonday.ISO8601).OnElements("time")
// Block and inline elements that impart no
// semantic meaning but style the document.
// Underlines, italics, bold, strikethrough etc.
p.AllowElements("b", "i", "pre", "small", "strike", "tt", "u")
// "del" "ins" are permitted
p.AllowAttrs("cite").Matching(bluemonday.Paragraph).OnElements("del", "ins")
p.AllowAttrs("datetime").Matching(bluemonday.ISO8601).OnElements("del", "ins")
// Enable ordered, unordered, and definition lists.
p.AllowLists()
// Class needed on span for mentions, which look like this when assembled:
// `<span class="h-card"><a href="https://example.org/users/targetAccount" class="u-url mention">@<span>someusername</span></a></span>`
p.AllowAttrs("class").OnElements("span")
/*
LANGUAGE FORMATTING
*/
// "bdi" "bdo" are permitted on "dir".
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/dir
p.AllowAttrs("dir").Matching(bluemonday.Direction).OnElements("bdi", "bdo")
// "rp" "rt" "ruby" are permitted. See:
// https://developer.mozilla.org/en-US/docs/Web/HTML/Element/rp
// https://developer.mozilla.org/en-US/docs/Web/HTML/Element/rt
// https://developer.mozilla.org/en-US/docs/Web/HTML/Element/ruby
p.AllowElements("rp", "rt", "ruby")
/*
CODE BLOCKS
*/
// Permit language tags for code elements.
p.AllowAttrs("class").Matching(regexp.MustCompile("^language-[a-zA-Z0-9]+$")).OnElements("code")
// Don't sanitize HTML inside code blocks.
p.SkipElementsContent("code", "pre")
/*
LINKS AND LINK SAFETY.
*/
// Permit hyperlinks.
p.AllowAttrs("class", "href", "rel").OnElements("a")
// URLs must be parseable by net/url.Parse().
p.RequireParseableURLs(true)
// Most common URL schemes only.
p.AllowURLSchemes("mailto", "http", "https")
// Force rel="noreferrer".
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/rel/noreferrer
p.RequireNoReferrerOnLinks(true)
// Add rel="nofollow" on all fully qualified (not relative) links.
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/rel#nofollow
p.RequireNoFollowOnFullyQualifiedLinks(true)
// Force crossorigin="anonymous"
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/crossorigin#anonymous
p.RequireCrossOriginAnonymous(true)
// Force target="_blank".
// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#target
p.AddTargetBlankToFullyQualifiedLinks(true)
return p
}()
// '[C]an be thought of as equivalent to stripping all HTML
// elements and their attributes as it has nothing on its allowlist.
// An example usage scenario would be blog post titles where HTML
// tags are not expected at all and if they are then the elements
// and the content of the elements should be stripped. This is a
// very strict policy.'
//
// Source: https://github.com/microcosm-cc/bluemonday#usage
var strict *bluemonday.Policy = bluemonday.StrictPolicy()
// removeHTML strictly removes *all* recognized HTML elements from the given string.
// removeHTML strictly removes *all* recognized
// HTML elements from the given string.
func removeHTML(in string) string {
return strict.Sanitize(in)
}
// SanitizeHTML sanitizes risky html elements from the given string, allowing only safe ones through.
func SanitizeHTML(in string) string {
// SanitizeToHTML sanitizes only risky html elements
// from the given string, allowing safe ones through.
func SanitizeToHTML(in string) string {
return regular.Sanitize(in)
}
// SanitizePlaintext runs text through basic sanitization. This removes
// any html elements that were in the string, and returns clean plaintext.
func SanitizePlaintext(in string) string {
// SanitizeToPlaintext runs text through basic sanitization.
// This removes any html elements that were in the string,
// and returns clean plaintext.
func SanitizeToPlaintext(in string) string {
// Unescape first to catch any tricky critters.
content := html.UnescapeString(in)
// Remove all detected HTML.
content = removeHTML(content)
// Unescape again to return plaintext.
content = html.UnescapeString(content)
return strings.TrimSpace(content)
}

28
internal/text/sanitize_test.go
View File

@ -36,30 +36,30 @@ type SanitizeTestSuite struct {
}
func (suite *SanitizeTestSuite) TestSanitizeOutgoing() {
s := text.SanitizeHTML(sanitizeOutgoing)
s := text.SanitizeToHTML(sanitizeOutgoing)
suite.Equal(sanitizedOutgoing, s)
}
func (suite *SanitizeTestSuite) TestSanitizeHTML() {
s := text.SanitizeHTML(sanitizeHTML)
s := text.SanitizeToHTML(sanitizeHTML)
suite.Equal(sanitizedHTML, s)
}
func (suite *SanitizeTestSuite) TestSanitizeCaption1() {
dodgyCaption := "<script>console.log('haha!')</script>this is just a normal caption ;)"
sanitized := text.SanitizePlaintext(dodgyCaption)
sanitized := text.SanitizeToPlaintext(dodgyCaption)
suite.Equal("this is just a normal caption ;)", sanitized)
}
func (suite *SanitizeTestSuite) TestSanitizeCaption2() {
dodgyCaption := "<em>here's a LOUD caption</em>"
sanitized := text.SanitizePlaintext(dodgyCaption)
sanitized := text.SanitizeToPlaintext(dodgyCaption)
suite.Equal("here's a LOUD caption", sanitized)
}
func (suite *SanitizeTestSuite) TestSanitizeCaption3() {
dodgyCaption := ""
sanitized := text.SanitizePlaintext(dodgyCaption)
sanitized := text.SanitizeToPlaintext(dodgyCaption)
suite.Equal("", sanitized)
}
@ -75,21 +75,21 @@ with some newlines
`
sanitized := text.SanitizePlaintext(dodgyCaption)
sanitized := text.SanitizeToPlaintext(dodgyCaption)
suite.Equal("here is\na multi line\ncaption\nwith some newlines", sanitized)
}
func (suite *SanitizeTestSuite) TestSanitizeCaption5() {
// html-escaped: "<script>console.log('aha!')</script> hello world"
dodgyCaption := `&lt;script&gt;console.log(&apos;aha!&apos;)&lt;/script&gt; hello world`
sanitized := text.SanitizePlaintext(dodgyCaption)
sanitized := text.SanitizeToPlaintext(dodgyCaption)
suite.Equal("hello world", sanitized)
}
func (suite *SanitizeTestSuite) TestSanitizeCaption6() {
// html-encoded: "<script>console.log('aha!')</script> hello world"
dodgyCaption := `&lt;&#115;&#99;&#114;&#105;&#112;&#116;&gt;&#99;&#111;&#110;&#115;&#111;&#108;&#101;&period;&#108;&#111;&#103;&lpar;&apos;&#97;&#104;&#97;&excl;&apos;&rpar;&lt;&sol;&#115;&#99;&#114;&#105;&#112;&#116;&gt;&#32;&#104;&#101;&#108;&#108;&#111;&#32;&#119;&#111;&#114;&#108;&#100;`
sanitized := text.SanitizePlaintext(dodgyCaption)
sanitized := text.SanitizeToPlaintext(dodgyCaption)
suite.Equal("hello world", sanitized)
}
@ -104,24 +104,30 @@ func (suite *SanitizeTestSuite) TestSanitizeCustomCSS() {
overflow: hidden;
text-overflow: ellipsis;
}`
sanitized := text.SanitizePlaintext(customCSS)
sanitized := text.SanitizeToPlaintext(customCSS)
suite.Equal(customCSS, sanitized) // should be the same as it was before
}
func (suite *SanitizeTestSuite) TestSanitizeNaughtyCustomCSS1() {
// try to break out of <style> into <head> and change the document title
customCSS := "</style><title>pee pee poo poo</title><style>"
sanitized := text.SanitizePlaintext(customCSS)
sanitized := text.SanitizeToPlaintext(customCSS)
suite.Empty(sanitized)
}
func (suite *SanitizeTestSuite) TestSanitizeNaughtyCustomCSS2() {
// try to break out of <style> into <head> and change the document title
customCSS := "pee pee poo poo</style><title></title><style>"
sanitized := text.SanitizePlaintext(customCSS)
sanitized := text.SanitizeToPlaintext(customCSS)
suite.Equal("pee pee poo poo", sanitized)
}
func (suite *SanitizeTestSuite) TestSanitizeInlineImg() {
withInlineImg := "<p>Here's an inline image: <img class=\"fixed-size-img svelte-uci8eb\" aria-hidden=\"false\" alt=\"A black-and-white photo of an Oblique Strategy card. The card reads: 'Define an area as 'safe' and use it as an anchor'.\" title=\"A black-and-white photo of an Oblique Strategy card. The card reads: 'Define an area as 'safe' and use it as an anchor'.\" width=\"0\" height=\"0\" src=\"https://example.org/fileserver/01H7J83147QMCE17C0RS9P10Y9/attachment/small/01H7J8365XXRTCP6CAMGEM49ZE.jpg\" style=\"object-position: 50% 50%;\"></p>"
sanitized := text.SanitizeToHTML(withInlineImg)
suite.Equal(`<p>Here&#39;s an inline image: </p>`, sanitized)
}
func TestSanitizeTestSuite(t *testing.T) {
suite.Run(t, new(SanitizeTestSuite))
}

4
internal/web/opengraph.go
View File

@ -67,7 +67,7 @@ func ogBase(instance *apimodel.InstanceV1) *ogMeta {
}
og := &ogMeta{
Title: text.SanitizePlaintext(instance.Title) + " - GoToSocial",
Title: text.SanitizeToPlaintext(instance.Title) + " - GoToSocial",
Type: "website",
Locale: locale,
URL: instance.URI,
@ -156,7 +156,7 @@ func parseTitle(account *apimodel.Account, accountDomain string) string {
// parseDescription returns a string description which is
// safe to use as a template.HTMLAttr inside templates.
func parseDescription(in string) string {
i := text.SanitizePlaintext(in)
i := text.SanitizeToPlaintext(in)
i = strings.ReplaceAll(i, "\n", " ")
i = strings.Join(strings.Fields(i), " ")
i = html.EscapeString(i)