html: use strings.EqualFold instead of lowering ourselves
Instead of using strings.ToLower and == to check case insensitive
equality, just use strings.EqualFold, even when the strings are only
ASCII. This prevents us unnecessarily lowering extremely long strings,
which can be a somewhat expensive operation, even if we're only
attempting to compare equality with five characters.
Thanks to Guido Vranken for reporting this issue.
Fixes golang/go#70906
Fixes CVE-2024-45338
Change-Id: I323b919f912d60dab6a87cadfdcac3e6b54cd128
Reviewed-on: https://go-review.googlesource.com/c/net/+/637536
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Roland Shoemaker <roland@golang.org>
Reviewed-by: Tatiana Bradley <tatianabradley@google.com>
diff --git a/html/doctype.go b/html/doctype.go
index c484e5a..bca3ae9 100644
--- a/html/doctype.go
+++ b/html/doctype.go
@@ -87,7 +87,7 @@
}
}
if lastAttr := n.Attr[len(n.Attr)-1]; lastAttr.Key == "system" &&
- strings.ToLower(lastAttr.Val) == "http://www.ibm.com/data/dtd/v11/ibmxhtml1-transitional.dtd" {
+ strings.EqualFold(lastAttr.Val, "http://www.ibm.com/data/dtd/v11/ibmxhtml1-transitional.dtd") {
quirks = true
}
}
diff --git a/html/foreign.go b/html/foreign.go
index 9da9e9d..e8515d8 100644
--- a/html/foreign.go
+++ b/html/foreign.go
@@ -40,8 +40,7 @@
if n.Data == "annotation-xml" {
for _, a := range n.Attr {
if a.Key == "encoding" {
- val := strings.ToLower(a.Val)
- if val == "text/html" || val == "application/xhtml+xml" {
+ if strings.EqualFold(a.Val, "text/html") || strings.EqualFold(a.Val, "application/xhtml+xml") {
return true
}
}
diff --git a/html/parse.go b/html/parse.go
index d67705d..643c674 100644
--- a/html/parse.go
+++ b/html/parse.go
@@ -1035,7 +1035,7 @@
if p.tok.DataAtom == a.Input {
for _, t := range p.tok.Attr {
if t.Key == "type" {
- if strings.ToLower(t.Val) == "hidden" {
+ if strings.EqualFold(t.Val, "hidden") {
// Skip setting framesetOK = false
return true
}
@@ -1463,7 +1463,7 @@
return inHeadIM(p)
case a.Input:
for _, t := range p.tok.Attr {
- if t.Key == "type" && strings.ToLower(t.Val) == "hidden" {
+ if t.Key == "type" && strings.EqualFold(t.Val, "hidden") {
p.addElement()
p.oe.pop()
return true
