From 711ca0c410a618b1e269d4348f545cec68347436 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Tue, 6 Apr 2021 02:35:50 +0200
Subject: [PATCH] Update to bluemonday-1.0.6 (#15294) (#15298)

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: zeripath <art27@cantab.net>
---
 go.mod                                        |  6 +--
 go.sum                                        |  9 ++--
 modules/markup/sanitizer.go                   |  4 +-
 modules/markup/sanitizer_test.go              | 12 +++++
 .../douceur/parser/parser.go                  |  0
 vendor/github.com/chris-ramon/douceur/LICENSE | 22 --------
 .../microcosm-cc/bluemonday/SECURITY.md       | 15 ++++++
 .../github.com/microcosm-cc/bluemonday/go.mod |  7 ++-
 .../github.com/microcosm-cc/bluemonday/go.sum | 11 ++--
 .../microcosm-cc/bluemonday/handlers.go       |  1 +
 .../microcosm-cc/bluemonday/policy.go         | 45 ++++++++++------
 .../microcosm-cc/bluemonday/sanitize.go       | 52 ++++++++++++++++---
 vendor/modules.txt                            |  8 ++-
 13 files changed, 125 insertions(+), 67 deletions(-)
 rename vendor/github.com/{chris-ramon => aymerick}/douceur/parser/parser.go (100%)
 delete mode 100644 vendor/github.com/chris-ramon/douceur/LICENSE
 create mode 100644 vendor/github.com/microcosm-cc/bluemonday/SECURITY.md

diff --git a/go.mod b/go.mod
index 27ea79e9c9..b8c0579147 100644
--- a/go.mod
+++ b/go.mod
@@ -70,7 +70,7 @@ require (
 	github.com/mgechev/dots v0.0.0-20190921121421-c36f7dcfbb81
 	github.com/mgechev/revive v1.0.3-0.20200921231451-246eac737dc7
 	github.com/mholt/archiver/v3 v3.3.0
-	github.com/microcosm-cc/bluemonday v1.0.5
+	github.com/microcosm-cc/bluemonday v1.0.6
 	github.com/minio/minio-go/v7 v7.0.4
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/msteinert/pam v0.0.0-20151204160544-02ccfbfaf0cc
@@ -105,7 +105,7 @@ require (
 	go.jolheiser.com/hcaptcha v0.0.4
 	go.jolheiser.com/pwn v0.0.3
 	golang.org/x/crypto v0.0.0-20201217014255-9d1352758620
-	golang.org/x/net v0.0.0-20210331212208-0fccb6fa2b5c
+	golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4
 	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
 	golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44
 	golang.org/x/text v0.3.3
@@ -124,5 +124,3 @@ require (
 )
 
 replace github.com/hashicorp/go-version => github.com/6543/go-version v1.2.4
-
-replace github.com/microcosm-cc/bluemonday => github.com/lunny/bluemonday v1.0.5-0.20201227154428-ca34796141e8
diff --git a/go.sum b/go.sum
index c6bc99578d..95dc2e318c 100644
--- a/go.sum
+++ b/go.sum
@@ -140,8 +140,6 @@ github.com/bradfitz/gomemcache v0.0.0-20190329173943-551aad21a668 h1:U/lr3Dgy4WK
 github.com/bradfitz/gomemcache v0.0.0-20190329173943-551aad21a668/go.mod h1:H0wQNHz2YrLsuXOZozoeDmnHXkNCRmMW0gwFWDfEZDA=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
-github.com/chris-ramon/douceur v0.2.0 h1:IDMEdxlEUUBYBKE4z/mJnFyVXox+MjuEVDJNN27glkU=
-github.com/chris-ramon/douceur v0.2.0/go.mod h1:wDW5xjJdeoMm1mRt4sD4c/LbF/mWdEpRXQKjTR8nIBE=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/cockroachdb/apd v1.1.0 h1:3LFP3629v+1aKXU5Q37mxmRxX/pIu1nijXydLShEq5I=
 github.com/cockroachdb/apd v1.1.0/go.mod h1:8Sl8LxpKi29FqWXR16WEFZRNSz3SoPzUzeMeY4+DwBQ=
@@ -598,8 +596,6 @@ github.com/lib/pq v1.3.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/lib/pq v1.7.0/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/lib/pq v1.8.1-0.20200908161135-083382b7e6fc h1:ERSU1OvZ6MdWhHieo2oT7xwR/HCksqKdgK6iYPU5pHI=
 github.com/lib/pq v1.8.1-0.20200908161135-083382b7e6fc/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
-github.com/lunny/bluemonday v1.0.5-0.20201227154428-ca34796141e8 h1:1omo92DLtxQu6VwVPSZAmduHaK5zssed6cvkHyl1XOg=
-github.com/lunny/bluemonday v1.0.5-0.20201227154428-ca34796141e8/go.mod h1:8iwZnFn2CDDNZ0r6UXhF4xawGvzaqzCRa1n3/lO3W2w=
 github.com/lunny/dingtalk_webhook v0.0.0-20171025031554-e3534c89ef96 h1:uNwtsDp7ci48vBTTxDuwcoTXz4lwtDTe7TjCQ0noaWY=
 github.com/lunny/dingtalk_webhook v0.0.0-20171025031554-e3534c89ef96/go.mod h1:mmIfjCSQlGYXmJ95jFN84AkQFnVABtKuJL8IrzwvUKQ=
 github.com/lunny/log v0.0.0-20160921050905-7887c61bf0de h1:nyxwRdWHAVxpFcDThedEgQ07DbcRc5xgNObtbTp76fk=
@@ -651,6 +647,8 @@ github.com/mgechev/revive v1.0.3-0.20200921231451-246eac737dc7 h1:ydVkpU/M4/c45y
 github.com/mgechev/revive v1.0.3-0.20200921231451-246eac737dc7/go.mod h1:no/hfevHbndpXR5CaJahkYCfM/FFpmM/dSOwFGU7Z1o=
 github.com/mholt/archiver/v3 v3.3.0 h1:vWjhY8SQp5yzM9P6OJ/eZEkmi3UAbRrxCq48MxjAzig=
 github.com/mholt/archiver/v3 v3.3.0/go.mod h1:YnQtqsp+94Rwd0D/rk5cnLrxusUBUXg+08Ebtr1Mqao=
+github.com/microcosm-cc/bluemonday v1.0.6 h1:ZOvqHKtnx0fUpnbQm3m3zKFWE+DRC+XB1onh8JoEObE=
+github.com/microcosm-cc/bluemonday v1.0.6/go.mod h1:HOT/6NaBlR0f9XlxD3zolN6Z3N8Lp4pvhp+jLS5ihnI=
 github.com/miekg/dns v1.0.14/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
 github.com/minio/md5-simd v1.1.0 h1:QPfiOqlZH+Cj9teu0t9b1nTBfPbyTl16Of5MeuShdK4=
 github.com/minio/md5-simd v1.1.0/go.mod h1:XpBqgZULrMYD3R+M28PcmP0CkI7PEMzB3U77ZrKZ0Gw=
@@ -996,8 +994,9 @@ golang.org/x/net v0.0.0-20200602114024-627f9648deb9/go.mod h1:qpuaurCH72eLCgpAm/
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20200707034311-ab3426394381/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20200822124328-c89045814202/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
-golang.org/x/net v0.0.0-20210331212208-0fccb6fa2b5c h1:KHUzaHIpjWVlVVNh65G3hhuj3KB1HnjY6Cq5cTvRQT8=
 golang.org/x/net v0.0.0-20210331212208-0fccb6fa2b5c/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
+golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4 h1:4nGaVu0QrbjT/AK2PRLuQfQuh6DJve+pELhqTdAj3x0=
+golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
 golang.org/x/oauth2 v0.0.0-20180620175406-ef147856a6dd/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20181106182150-f42d05182288/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
diff --git a/modules/markup/sanitizer.go b/modules/markup/sanitizer.go
index ba73650bdf..23b109c8d5 100644
--- a/modules/markup/sanitizer.go
+++ b/modules/markup/sanitizer.go
@@ -46,7 +46,9 @@ func ReplaceSanitizer() {
 	sanitizer.policy.AllowAttrs("checked", "disabled", "readonly").OnElements("input")
 
 	// Custom URL-Schemes
-	sanitizer.policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
+	if len(setting.Markdown.CustomURLSchemes) > 0 {
+		sanitizer.policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
+	}
 
 	// Allow keyword markup
 	sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^` + keywordClass + `$`)).OnElements("span")
diff --git a/modules/markup/sanitizer_test.go b/modules/markup/sanitizer_test.go
index 3e8dcecd50..6334085307 100644
--- a/modules/markup/sanitizer_test.go
+++ b/modules/markup/sanitizer_test.go
@@ -6,6 +6,8 @@
 package markup
 
 import (
+	"html/template"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -50,3 +52,13 @@ func Test_Sanitizer(t *testing.T) {
 		assert.Equal(t, testCases[i+1], string(SanitizeBytes([]byte(testCases[i]))))
 	}
 }
+
+func TestSanitizeNonEscape(t *testing.T) {
+	descStr := "<scrİpt>&lt;script&gt;alert(document.domain)&lt;/script&gt;</scrİpt>"
+
+	output := template.HTML(Sanitize(string(descStr)))
+	if strings.Contains(string(output), "<script>") {
+		t.Errorf("un-escaped <script> in output: %q", output)
+	}
+
+}
diff --git a/vendor/github.com/chris-ramon/douceur/parser/parser.go b/vendor/github.com/aymerick/douceur/parser/parser.go
similarity index 100%
rename from vendor/github.com/chris-ramon/douceur/parser/parser.go
rename to vendor/github.com/aymerick/douceur/parser/parser.go
diff --git a/vendor/github.com/chris-ramon/douceur/LICENSE b/vendor/github.com/chris-ramon/douceur/LICENSE
deleted file mode 100644
index 6ce87cd374..0000000000
--- a/vendor/github.com/chris-ramon/douceur/LICENSE
+++ /dev/null
@@ -1,22 +0,0 @@
-The MIT License (MIT)
-
-Copyright (c) 2015 Aymerick JEHANNE
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
-
diff --git a/vendor/github.com/microcosm-cc/bluemonday/SECURITY.md b/vendor/github.com/microcosm-cc/bluemonday/SECURITY.md
new file mode 100644
index 0000000000..a344e7c050
--- /dev/null
+++ b/vendor/github.com/microcosm-cc/bluemonday/SECURITY.md
@@ -0,0 +1,15 @@
+# Security Policy
+
+## Supported Versions
+
+Latest tag and tip are supported.
+
+Older tags remain present but changes result in new tags and are not back ported... please verify any issue against the latest tag and tip.
+
+## Reporting a Vulnerability
+
+Email: <bluemonday@buro9.com>
+
+Bluemonday is pure OSS and not maintained by a company. As such there is no bug bounty program but security issues will be taken seriously and resolved as soon as possible.
+
+The maintainer lives in the United Kingdom and whilst the email is monitored expect a reply or ACK when the maintainer is awake.
diff --git a/vendor/github.com/microcosm-cc/bluemonday/go.mod b/vendor/github.com/microcosm-cc/bluemonday/go.mod
index 47b521a75b..0ff3d77b03 100644
--- a/vendor/github.com/microcosm-cc/bluemonday/go.mod
+++ b/vendor/github.com/microcosm-cc/bluemonday/go.mod
@@ -1,10 +1,9 @@
 module github.com/microcosm-cc/bluemonday
 
-go 1.9
+go 1.16
 
 require (
-	github.com/aymerick/douceur v0.2.0 // indirect
-	github.com/chris-ramon/douceur v0.2.0
+	github.com/aymerick/douceur v0.2.0
 	github.com/gorilla/css v1.0.0 // indirect
-	golang.org/x/net v0.0.0-20181220203305-927f97764cc3
+	golang.org/x/net v0.0.0-20210331212208-0fccb6fa2b5c
 )
diff --git a/vendor/github.com/microcosm-cc/bluemonday/go.sum b/vendor/github.com/microcosm-cc/bluemonday/go.sum
index 8c34e7a404..7955d9eb02 100644
--- a/vendor/github.com/microcosm-cc/bluemonday/go.sum
+++ b/vendor/github.com/microcosm-cc/bluemonday/go.sum
@@ -1,8 +1,11 @@
 github.com/aymerick/douceur v0.2.0 h1:Mv+mAeH1Q+n9Fr+oyamOlAkUNPWPlA8PPGR0QAaYuPk=
 github.com/aymerick/douceur v0.2.0/go.mod h1:wlT5vV2O3h55X9m7iVYN0TBM0NH/MmbLnd30/FjWUq4=
-github.com/chris-ramon/douceur v0.2.0 h1:IDMEdxlEUUBYBKE4z/mJnFyVXox+MjuEVDJNN27glkU=
-github.com/chris-ramon/douceur v0.2.0/go.mod h1:wDW5xjJdeoMm1mRt4sD4c/LbF/mWdEpRXQKjTR8nIBE=
 github.com/gorilla/css v1.0.0 h1:BQqNyPTi50JCFMTw/b67hByjMVXZRwGha6wxVGkeihY=
 github.com/gorilla/css v1.0.0/go.mod h1:Dn721qIggHpt4+EFCcTLTU/vk5ySda2ReITrtgBl60c=
-golang.org/x/net v0.0.0-20181220203305-927f97764cc3 h1:eH6Eip3UpmR+yM/qI9Ijluzb1bNv/cAU/n+6l8tRSis=
-golang.org/x/net v0.0.0-20181220203305-927f97764cc3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20210331212208-0fccb6fa2b5c h1:KHUzaHIpjWVlVVNh65G3hhuj3KB1HnjY6Cq5cTvRQT8=
+golang.org/x/net v0.0.0-20210331212208-0fccb6fa2b5c/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
diff --git a/vendor/github.com/microcosm-cc/bluemonday/handlers.go b/vendor/github.com/microcosm-cc/bluemonday/handlers.go
index 1ef4c8acd0..9753d6e952 100644
--- a/vendor/github.com/microcosm-cc/bluemonday/handlers.go
+++ b/vendor/github.com/microcosm-cc/bluemonday/handlers.go
@@ -26,6 +26,7 @@
 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 package bluemonday
 
 import (
diff --git a/vendor/github.com/microcosm-cc/bluemonday/policy.go b/vendor/github.com/microcosm-cc/bluemonday/policy.go
index 739d302c30..9c7e662fc2 100644
--- a/vendor/github.com/microcosm-cc/bluemonday/policy.go
+++ b/vendor/github.com/microcosm-cc/bluemonday/policy.go
@@ -69,6 +69,9 @@ type Policy struct {
 	// Will skip for href="/foo" or href="foo"
 	requireNoReferrerFullyQualifiedLinks bool
 
+	// When true, add crossorigin="anonymous" to HTML audio, img, link, script, and video tags
+	requireCrossOriginAnonymous bool
+
 	// When true add target="_blank" to fully qualified links
 	// Will add for href="http://foo"
 	// Will skip for href="/foo" or href="foo"
@@ -433,25 +436,25 @@ func (spb *stylePolicyBuilder) OnElements(elements ...string) *Policy {
 // and return the updated policy
 func (spb *stylePolicyBuilder) OnElementsMatching(regex *regexp.Regexp) *Policy {
 
-		for _, attr := range spb.propertyNames {
+	for _, attr := range spb.propertyNames {
 
-			if _, ok := spb.p.elsMatchingAndStyles[regex]; !ok {
-				spb.p.elsMatchingAndStyles[regex] = make(map[string]stylePolicy)
-			}
-
-			sp := stylePolicy{}
-			if spb.handler != nil {
-				sp.handler = spb.handler
-			} else if len(spb.enum) > 0 {
-				sp.enum = spb.enum
-			} else if spb.regexp != nil {
-				sp.regexp = spb.regexp
-			} else {
-				sp.handler = getDefaultHandler(attr)
-			}
-			spb.p.elsMatchingAndStyles[regex][attr] = sp
+		if _, ok := spb.p.elsMatchingAndStyles[regex]; !ok {
+			spb.p.elsMatchingAndStyles[regex] = make(map[string]stylePolicy)
 		}
 
+		sp := stylePolicy{}
+		if spb.handler != nil {
+			sp.handler = spb.handler
+		} else if len(spb.enum) > 0 {
+			sp.enum = spb.enum
+		} else if spb.regexp != nil {
+			sp.regexp = spb.regexp
+		} else {
+			sp.handler = getDefaultHandler(attr)
+		}
+		spb.p.elsMatchingAndStyles[regex][attr] = sp
+	}
+
 	return spb.p
 }
 
@@ -558,6 +561,16 @@ func (p *Policy) RequireNoReferrerOnFullyQualifiedLinks(require bool) *Policy {
 	return p
 }
 
+// RequireCrossOriginAnonymous will result in all audio, img, link, script, and
+// video tags having a crossorigin="anonymous" added to them if one does not
+// already exist
+func (p *Policy) RequireCrossOriginAnonymous(require bool) *Policy {
+
+	p.requireCrossOriginAnonymous = require
+
+	return p
+}
+
 // AddTargetBlankToFullyQualifiedLinks will result in all a, area and link tags
 // that point to a non-local destination (i.e. starts with a protocol and has a
 // host) having a target="_blank" added to them if one does not already exist
diff --git a/vendor/github.com/microcosm-cc/bluemonday/sanitize.go b/vendor/github.com/microcosm-cc/bluemonday/sanitize.go
index a58333aa65..99559bbabe 100644
--- a/vendor/github.com/microcosm-cc/bluemonday/sanitize.go
+++ b/vendor/github.com/microcosm-cc/bluemonday/sanitize.go
@@ -39,7 +39,7 @@ import (
 
 	"golang.org/x/net/html"
 
-	cssparser "github.com/chris-ramon/douceur/parser"
+	"github.com/aymerick/douceur/parser"
 )
 
 var (
@@ -286,7 +286,7 @@ func (p *Policy) sanitize(r io.Reader) *bytes.Buffer {
 
 		case html.StartTagToken:
 
-			mostRecentlyStartedToken = strings.ToLower(token.Data)
+			mostRecentlyStartedToken = normaliseElementName(token.Data)
 
 			aps, ok := p.elsAndAttrs[token.Data]
 			if !ok {
@@ -329,7 +329,7 @@ func (p *Policy) sanitize(r io.Reader) *bytes.Buffer {
 
 		case html.EndTagToken:
 
-			if mostRecentlyStartedToken == strings.ToLower(token.Data) {
+			if mostRecentlyStartedToken == normaliseElementName(token.Data) {
 				mostRecentlyStartedToken = ""
 			}
 
@@ -407,11 +407,11 @@ func (p *Policy) sanitize(r io.Reader) *bytes.Buffer {
 
 			if !skipElementContent {
 				switch mostRecentlyStartedToken {
-				case "script":
+				case `script`:
 					// not encouraged, but if a policy allows JavaScript we
 					// should not HTML escape it as that would break the output
 					buff.WriteString(token.Data)
-				case "style":
+				case `style`:
 					// not encouraged, but if a policy allows CSS styles we
 					// should not HTML escape it as that would break the output
 					buff.WriteString(token.Data)
@@ -721,6 +721,26 @@ func (p *Policy) sanitizeAttrs(
 		}
 	}
 
+	if p.requireCrossOriginAnonymous && len(cleanAttrs) > 0 {
+		switch elementName {
+		case "audio", "img", "link", "script", "video":
+			var crossOriginFound bool
+			for _, htmlAttr := range cleanAttrs {
+				if htmlAttr.Key == "crossorigin" {
+					crossOriginFound = true
+					htmlAttr.Val = "anonymous"
+				}
+			}
+
+			if !crossOriginFound {
+				crossOrigin := html.Attribute{}
+				crossOrigin.Key = "crossorigin"
+				crossOrigin.Val = "anonymous"
+				cleanAttrs = append(cleanAttrs, crossOrigin)
+			}
+		}
+	}
+
 	return cleanAttrs
 }
 
@@ -744,7 +764,7 @@ func (p *Policy) sanitizeStyles(attr html.Attribute, elementName string) html.At
 	if len(attr.Val) > 0 && attr.Val[len(attr.Val)-1] != ';' {
 		attr.Val = attr.Val + ";"
 	}
-	decs, err := cssparser.ParseDeclarations(attr.Val)
+	decs, err := parser.ParseDeclarations(attr.Val)
 	if err != nil {
 		attr.Val = ""
 		return attr
@@ -944,3 +964,23 @@ func (p *Policy) matchRegex(elementName string) (map[string]attrPolicy, bool) {
 	}
 	return aps, matched
 }
+
+
+// normaliseElementName takes a HTML element like <script> which is user input
+// and returns a lower case version of it that is immune to UTF-8 to ASCII
+// conversion tricks (like the use of upper case cyrillic i scrİpt which a
+// strings.ToLower would convert to script). Instead this func will preserve
+// all non-ASCII as their escaped equivalent, i.e. \u0130 which reveals the
+// characters when lower cased
+func normaliseElementName(str string) string {
+	// that useful QuoteToASCII put quote marks at the start and end
+	// so those are trimmed off
+	return strings.TrimSuffix(
+		strings.TrimPrefix(
+			strings.ToLower(
+				strconv.QuoteToASCII(str),
+			),
+			`"`),
+		`"`,
+	)
+}
\ No newline at end of file
diff --git a/vendor/modules.txt b/vendor/modules.txt
index d5bcdaedc7..45db44aed7 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -103,6 +103,7 @@ github.com/anmitsu/go-shlex
 github.com/asaskevich/govalidator
 # github.com/aymerick/douceur v0.2.0
 github.com/aymerick/douceur/css
+github.com/aymerick/douceur/parser
 # github.com/beorn7/perks v1.0.1
 github.com/beorn7/perks/quantile
 # github.com/blevesearch/bleve v1.0.10
@@ -169,8 +170,6 @@ github.com/boombuler/barcode/qr
 github.com/boombuler/barcode/utils
 # github.com/bradfitz/gomemcache v0.0.0-20190329173943-551aad21a668
 github.com/bradfitz/gomemcache/memcache
-# github.com/chris-ramon/douceur v0.2.0
-github.com/chris-ramon/douceur/parser
 # github.com/couchbase/gomemcached v0.0.0-20191004160342-7b5da2ec40b2
 ## explicit
 github.com/couchbase/gomemcached
@@ -566,7 +565,7 @@ github.com/mgechev/revive/rule
 # github.com/mholt/archiver/v3 v3.3.0
 ## explicit
 github.com/mholt/archiver/v3
-# github.com/microcosm-cc/bluemonday v1.0.5 => github.com/lunny/bluemonday v1.0.5-0.20201227154428-ca34796141e8
+# github.com/microcosm-cc/bluemonday v1.0.6
 ## explicit
 github.com/microcosm-cc/bluemonday
 # github.com/minio/md5-simd v1.1.0
@@ -809,7 +808,7 @@ golang.org/x/crypto/ssh/knownhosts
 # golang.org/x/mod v0.3.0
 golang.org/x/mod/module
 golang.org/x/mod/semver
-# golang.org/x/net v0.0.0-20210331212208-0fccb6fa2b5c
+# golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4
 ## explicit
 golang.org/x/net/context
 golang.org/x/net/context/ctxhttp
@@ -979,4 +978,3 @@ xorm.io/xorm/names
 xorm.io/xorm/schemas
 xorm.io/xorm/tags
 # github.com/hashicorp/go-version => github.com/6543/go-version v1.2.4
-# github.com/microcosm-cc/bluemonday => github.com/lunny/bluemonday v1.0.5-0.20201227154428-ca34796141e8