Upgrade to Go 1.21.1

See https://github.com/golang/go/issues?q=milestone%3AGo1.21.1+label%3ACherryPickApproved

Fixes #11474
Fixes #11414

5 files changed, 186 insertions, 45 deletions

diff --git a/tpl/internal/go_templates/htmltemplate/context.go b/tpl/internal/go_templates/htmltemplate/context.go
index 9f592b57f..061f17ddb 100644
--- a/tpl/internal/go_templates/htmltemplate/context.go
+++ b/tpl/internal/go_templates/htmltemplate/context.go
@@ -129,6 +129,10 @@ const (
 	stateJSBlockCmt
 	// stateJSLineCmt occurs inside a JavaScript // line comment.
 	stateJSLineCmt
+	// stateJSHTMLOpenCmt occurs inside a JavaScript <!-- HTML-like comment.
+	stateJSHTMLOpenCmt
+	// stateJSHTMLCloseCmt occurs inside a JavaScript --> HTML-like comment.
+	stateJSHTMLCloseCmt
 	// stateCSS occurs inside a <style> element or style attribute.
 	stateCSS
 	// stateCSSDqStr occurs inside a CSS double quoted string.
@@ -156,7 +160,7 @@ const (
 // authors & maintainers, not for end-users or machines.
 func isComment(s state) bool {
 	switch s {
-	case stateHTMLCmt, stateJSBlockCmt, stateJSLineCmt, stateCSSBlockCmt, stateCSSLineCmt:
+	case stateHTMLCmt, stateJSBlockCmt, stateJSLineCmt, stateJSHTMLOpenCmt, stateJSHTMLCloseCmt, stateCSSBlockCmt, stateCSSLineCmt:
 		return true
 	}
 	return false
@@ -171,6 +175,20 @@ func isInTag(s state) bool {
 	return false
 }
 
+// isInScriptLiteral returns true if s is one of the literal states within a
+// <script> tag, and as such occurances of "<!--", "<script", and "</script"
+// need to be treated specially.
+func isInScriptLiteral(s state) bool {
+	// Ignore the comment states (stateJSBlockCmt, stateJSLineCmt,
+	// stateJSHTMLOpenCmt, stateJSHTMLCloseCmt) because their content is already
+	// omitted from the output.
+	switch s {
+	case stateJSDqStr, stateJSSqStr, stateJSBqStr, stateJSRegexp:
+		return true
+	}
+	return false
+}
+
 // delim is the delimiter that will end the current HTML attribute.
 type delim uint8
 
diff --git a/tpl/internal/go_templates/htmltemplate/escape.go b/tpl/internal/go_templates/htmltemplate/escape.go
index f6b2e4b34..5d47a83d3 100644
--- a/tpl/internal/go_templates/htmltemplate/escape.go
+++ b/tpl/internal/go_templates/htmltemplate/escape.go
@@ -11,6 +11,7 @@ import (
 
 	//"internal/godebug"
 	"io"
+	"regexp"
 
 	template "github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate"
 	"github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate/parse"
@@ -231,7 +232,7 @@ func (e *escaper) escapeAction(c context, n *parse.ActionNode) context {
 		s = append(s, "_html_template_jsstrescaper")
 	case stateJSBqStr:
 		if SecurityAllowActionJSTmpl.Load() {
-			//debugAllowActionJSTmpl.IncNonDefault()
+			// debugAllowActionJSTmpl.IncNonDefault()
 			s = append(s, "_html_template_jsstrescaper")
 		} else {
 			return context{
@@ -732,6 +733,26 @@ var delimEnds = [...]string{
 	delimSpaceOrTagEnd: " \t\n\f\r>",
 }
 
+var (
+	// Per WHATWG HTML specification, section 4.12.1.3, there are extremely
+	// complicated rules for how to handle the set of opening tags <!--,
+	// <script, and </script when they appear in JS literals (i.e. strings,
+	// regexs, and comments). The specification suggests a simple solution,
+	// rather than implementing the arcane ABNF, which involves simply escaping
+	// the opening bracket with \x3C. We use the below regex for this, since it
+	// makes doing the case-insensitive find-replace much simpler.
+	specialScriptTagRE          = regexp.MustCompile("(?i)<(script|/script|!--)")
+	specialScriptTagReplacement = []byte("\\x3C$1")
+)
+
+func containsSpecialScriptTag(s []byte) bool {
+	return specialScriptTagRE.Match(s)
+}
+
+func escapeSpecialScriptTags(s []byte) []byte {
+	return specialScriptTagRE.ReplaceAll(s, specialScriptTagReplacement)
+}
+
 var doctypeBytes = []byte("<!DOCTYPE")
 
 // escapeText escapes a text template node.
@@ -780,13 +801,21 @@ func (e *escaper) escapeText(c context, n *parse.TextNode) context {
 		if c.state != c1.state && isComment(c1.state) && c1.delim == delimNone {
 			// Preserve the portion between written and the comment start.
 			cs := i1 - 2
-			if c1.state == stateHTMLCmt {
+			if c1.state == stateHTMLCmt || c1.state == stateJSHTMLOpenCmt {
 				// "<!--" instead of "/*" or "//"
 				cs -= 2
+			} else if c1.state == stateJSHTMLCloseCmt {
+				// "-->" instead of "/*" or "//"
+				cs -= 1
 			}
 			b.Write(s[written:cs])
 			written = i1
 		}
+		if isInScriptLiteral(c.state) && containsSpecialScriptTag(s[i:i1]) {
+			b.Write(s[written:i])
+			b.Write(escapeSpecialScriptTags(s[i:i1]))
+			written = i1
+		}
 		if i == i1 && c.state == c1.state {
 			panic(fmt.Sprintf("infinite loop from %v to %v on %q..%q", c, c1, s[:i], s[i:]))
 		}
diff --git a/tpl/internal/go_templates/htmltemplate/escape_test.go b/tpl/internal/go_templates/htmltemplate/escape_test.go
index 680ba6fa7..4ad5316fb 100644
--- a/tpl/internal/go_templates/htmltemplate/escape_test.go
+++ b/tpl/internal/go_templates/htmltemplate/escape_test.go
@@ -509,6 +509,31 @@ func TestEscape(t *testing.T) {
 			"<script>var a \nd</script>",
 		},
 		{
+			"JS HTML-like comments",
+			"<script>before <!-- beep\nbetween\nbefore-->boop\n</script>",
+			"<script>before \nbetween\nbefore\n</script>",
+		},
+		{
+			"JS hashbang comment",
+			"<script>#! beep\n</script>",
+			"<script>\n</script>",
+		},
+		{
+			"Special tags in <script> string literals",
+			`<script>var a = "asd < 123 <!-- 456 < fgh <script jkl < 789 </script"</script>`,
+			`<script>var a = "asd < 123 \x3C!-- 456 < fgh \x3Cscript jkl < 789 \x3C/script"</script>`,
+		},
+		{
+			"Special tags in <script> string literals (mixed case)",
+			`<script>var a = "<!-- <ScripT </ScripT"</script>`,
+			`<script>var a = "\x3C!-- \x3CScripT \x3C/ScripT"</script>`,
+		},
+		{
+			"Special tags in <script> regex literals (mixed case)",
+			`<script>var a = /<!-- <ScripT </ScripT/</script>`,
+			`<script>var a = /\x3C!-- \x3CScripT \x3C/ScripT/</script>`,
+		},
+		{
 			"CSS comments",
 			"<style>p// paragraph\n" +
 				`{border: 1px/* color */{{"#00f"}}}</style>`,
@@ -1528,8 +1553,38 @@ func TestEscapeText(t *testing.T) {
 			context{state: stateJS, element: elementScript},
 		},
 		{
+			// <script and </script tags are escaped, so </script> should not
+			// cause us to exit the JS state.
 			`<script>document.write("<script>alert(1)</script>");`,
-			context{state: stateText},
+			context{state: stateJS, element: elementScript},
+		},
+		{
+			`<script>document.write("<script>`,
+			context{state: stateJSDqStr, element: elementScript},
+		},
+		{
+			`<script>document.write("<script>alert(1)</script>`,
+			context{state: stateJSDqStr, element: elementScript},
+		},
+		{
+			`<script>document.write("<script>alert(1)<!--`,
+			context{state: stateJSDqStr, element: elementScript},
+		},
+		{
+			`<script>document.write("<script>alert(1)</Script>");`,
+			context{state: stateJS, element: elementScript},
+		},
+		{
+			`<script>document.write("<!--");`,
+			context{state: stateJS, element: elementScript},
+		},
+		{
+			`<script>let a = /</script`,
+			context{state: stateJSRegexp, element: elementScript},
+		},
+		{
+			`<script>let a = /</script/`,
+			context{state: stateJS, element: elementScript, jsCtx: jsCtxDivOp},
 		},
 		{
 			`<script type="text/template">`,
diff --git a/tpl/internal/go_templates/htmltemplate/state_string.go b/tpl/internal/go_templates/htmltemplate/state_string.go
index 6fb1a6eeb..be7a92051 100644
--- a/tpl/internal/go_templates/htmltemplate/state_string.go
+++ b/tpl/internal/go_templates/htmltemplate/state_string.go
@@ -25,21 +25,23 @@ func _() {
 	_ = x[stateJSRegexp-14]
 	_ = x[stateJSBlockCmt-15]
 	_ = x[stateJSLineCmt-16]
-	_ = x[stateCSS-17]
-	_ = x[stateCSSDqStr-18]
-	_ = x[stateCSSSqStr-19]
-	_ = x[stateCSSDqURL-20]
-	_ = x[stateCSSSqURL-21]
-	_ = x[stateCSSURL-22]
-	_ = x[stateCSSBlockCmt-23]
-	_ = x[stateCSSLineCmt-24]
-	_ = x[stateError-25]
-	_ = x[stateDead-26]
+	_ = x[stateJSHTMLOpenCmt-17]
+	_ = x[stateJSHTMLCloseCmt-18]
+	_ = x[stateCSS-19]
+	_ = x[stateCSSDqStr-20]
+	_ = x[stateCSSSqStr-21]
+	_ = x[stateCSSDqURL-22]
+	_ = x[stateCSSSqURL-23]
+	_ = x[stateCSSURL-24]
+	_ = x[stateCSSBlockCmt-25]
+	_ = x[stateCSSLineCmt-26]
+	_ = x[stateError-27]
+	_ = x[stateDead-28]
 }
 
-const _state_name = "stateTextstateTagstateAttrNamestateAfterNamestateBeforeValuestateHTMLCmtstateRCDATAstateAttrstateURLstateSrcsetstateJSstateJSDqStrstateJSSqStrstateJSBqStrstateJSRegexpstateJSBlockCmtstateJSLineCmtstateCSSstateCSSDqStrstateCSSSqStrstateCSSDqURLstateCSSSqURLstateCSSURLstateCSSBlockCmtstateCSSLineCmtstateErrorstateDead"
+const _state_name = "stateTextstateTagstateAttrNamestateAfterNamestateBeforeValuestateHTMLCmtstateRCDATAstateAttrstateURLstateSrcsetstateJSstateJSDqStrstateJSSqStrstateJSBqStrstateJSRegexpstateJSBlockCmtstateJSLineCmtstateJSHTMLOpenCmtstateJSHTMLCloseCmtstateCSSstateCSSDqStrstateCSSSqStrstateCSSDqURLstateCSSSqURLstateCSSURLstateCSSBlockCmtstateCSSLineCmtstateErrorstateDead"
 
-var _state_index = [...]uint16{0, 9, 17, 30, 44, 60, 72, 83, 92, 100, 111, 118, 130, 142, 154, 167, 182, 196, 204, 217, 230, 243, 256, 267, 283, 298, 308, 317}
+var _state_index = [...]uint16{0, 9, 17, 30, 44, 60, 72, 83, 92, 100, 111, 118, 130, 142, 154, 167, 182, 196, 214, 233, 241, 254, 267, 280, 293, 304, 320, 335, 345, 354}
 
 func (i state) String() string {
 	if i >= state(len(_state_index)-1) {
diff --git a/tpl/internal/go_templates/htmltemplate/transition.go b/tpl/internal/go_templates/htmltemplate/transition.go
index 3b9fbfb68..432c365d3 100644
--- a/tpl/internal/go_templates/htmltemplate/transition.go
+++ b/tpl/internal/go_templates/htmltemplate/transition.go
@@ -14,32 +14,34 @@ import (
 // the updated context and the number of bytes consumed from the front of the
 // input.
 var transitionFunc = [...]func(context, []byte) (context, int){
-	stateText:        tText,
-	stateTag:         tTag,
-	stateAttrName:    tAttrName,
-	stateAfterName:   tAfterName,
-	stateBeforeValue: tBeforeValue,
-	stateHTMLCmt:     tHTMLCmt,
-	stateRCDATA:      tSpecialTagEnd,
-	stateAttr:        tAttr,
-	stateURL:         tURL,
-	stateSrcset:      tURL,
-	stateJS:          tJS,
-	stateJSDqStr:     tJSDelimited,
-	stateJSSqStr:     tJSDelimited,
-	stateJSBqStr:     tJSDelimited,
-	stateJSRegexp:    tJSDelimited,
-	stateJSBlockCmt:  tBlockCmt,
-	stateJSLineCmt:   tLineCmt,
-	stateCSS:         tCSS,
-	stateCSSDqStr:    tCSSStr,
-	stateCSSSqStr:    tCSSStr,
-	stateCSSDqURL:    tCSSStr,
-	stateCSSSqURL:    tCSSStr,
-	stateCSSURL:      tCSSStr,
-	stateCSSBlockCmt: tBlockCmt,
-	stateCSSLineCmt:  tLineCmt,
-	stateError:       tError,
+	stateText:           tText,
+	stateTag:            tTag,
+	stateAttrName:       tAttrName,
+	stateAfterName:      tAfterName,
+	stateBeforeValue:    tBeforeValue,
+	stateHTMLCmt:        tHTMLCmt,
+	stateRCDATA:         tSpecialTagEnd,
+	stateAttr:           tAttr,
+	stateURL:            tURL,
+	stateSrcset:         tURL,
+	stateJS:             tJS,
+	stateJSDqStr:        tJSDelimited,
+	stateJSSqStr:        tJSDelimited,
+	stateJSBqStr:        tJSDelimited,
+	stateJSRegexp:       tJSDelimited,
+	stateJSBlockCmt:     tBlockCmt,
+	stateJSLineCmt:      tLineCmt,
+	stateJSHTMLOpenCmt:  tLineCmt,
+	stateJSHTMLCloseCmt: tLineCmt,
+	stateCSS:            tCSS,
+	stateCSSDqStr:       tCSSStr,
+	stateCSSSqStr:       tCSSStr,
+	stateCSSDqURL:       tCSSStr,
+	stateCSSSqURL:       tCSSStr,
+	stateCSSURL:         tCSSStr,
+	stateCSSBlockCmt:    tBlockCmt,
+	stateCSSLineCmt:     tLineCmt,
+	stateError:          tError,
 }
 
 var commentStart = []byte("<!--")
@@ -212,6 +214,11 @@ var (
 // element states.
 func tSpecialTagEnd(c context, s []byte) (context, int) {
 	if c.element != elementNone {
+		// script end tags ("</script") within script literals are ignored, so that
+		// we can properly escape them.
+		if c.element == elementScript && (isInScriptLiteral(c.state) || isComment(c.state)) {
+			return c, len(s)
+		}
 		if i := indexTagEnd(s, specialTagEndMarkers[c.element]); i != -1 {
 			return context{}, i
 		}
@@ -263,7 +270,7 @@ func tURL(c context, s []byte) (context, int) {
 
 // tJS is the context transition function for the JS state.
 func tJS(c context, s []byte) (context, int) {
-	i := bytes.IndexAny(s, "\"`'/")
+	i := bytes.IndexAny(s, "\"`'/<-#")
 	if i == -1 {
 		// Entire input is non string, comment, regexp tokens.
 		c.jsCtx = nextJSCtx(s, c.jsCtx)
@@ -293,6 +300,26 @@ func tJS(c context, s []byte) (context, int) {
 				err:   errorf(ErrSlashAmbig, nil, 0, "'/' could start a division or regexp: %.32q", s[i:]),
 			}, len(s)
 		}
+	// ECMAScript supports HTML style comments for legacy reasons, see Appendix
+	// B.1.1 "HTML-like Comments". The handling of these comments is somewhat
+	// confusing. Multi-line comments are not supported, i.e. anything on lines
+	// between the opening and closing tokens is not considered a comment, but
+	// anything following the opening or closing token, on the same line, is
+	// ignored. As such we simply treat any line prefixed with "<!--" or "-->"
+	// as if it were actually prefixed with "//" and move on.
+	case '<':
+		if i+3 < len(s) && bytes.Equal(commentStart, s[i:i+4]) {
+			c.state, i = stateJSHTMLOpenCmt, i+3
+		}
+	case '-':
+		if i+2 < len(s) && bytes.Equal(commentEnd, s[i:i+3]) {
+			c.state, i = stateJSHTMLCloseCmt, i+2
+		}
+	// ECMAScript also supports "hashbang" comment lines, see Section 12.5.
+	case '#':
+		if i+1 < len(s) && s[i+1] == '!' {
+			c.state, i = stateJSLineCmt, i+1
+		}
 	default:
 		panic("unreachable")
 	}
@@ -331,6 +358,16 @@ func tJSDelimited(c context, s []byte) (context, int) {
 			inCharset = true
 		case ']':
 			inCharset = false
+		case '/':
+			// If "</script" appears in a regex literal, the '/' should not
+			// close the regex literal, and it will later be escaped to
+			// "\x3C/script" in escapeText.
+			if i > 0 && i+7 <= len(s) && bytes.Compare(bytes.ToLower(s[i-1:i+7]), []byte("</script")) == 0 {
+				i++
+			} else if !inCharset {
+				c.state, c.jsCtx = stateJS, jsCtxDivOp
+				return c, i + 1
+			}
 		default:
 			// end delimiter
 			if !inCharset {
@@ -372,12 +409,12 @@ func tBlockCmt(c context, s []byte) (context, int) {
 	return c, i + 2
 }
 
-// tLineCmt is the context transition function for //comment states.
+// tLineCmt is the context transition function for //comment states, and the JS HTML-like comment state.
 func tLineCmt(c context, s []byte) (context, int) {
 	var lineTerminators string
 	var endState state
 	switch c.state {
-	case stateJSLineCmt:
+	case stateJSLineCmt, stateJSHTMLOpenCmt, stateJSHTMLCloseCmt:
 		lineTerminators, endState = "\n\r\u2028\u2029", stateJS
 	case stateCSSLineCmt:
 		lineTerminators, endState = "\n\f\r", stateCSS