LibWeb: Fix crash in Headers::get with non-ASCII characters

headers list is ISO-8859-1 encoded using `Infra::isomorphic_encode`, so we should use decode them using `Infra::isomorphic_decode` before return.
LadybirdBrowser · Dec 7, 2024 · 0b18dd5 · 0b18dd5
1 parent 46b9518
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Showing 3 changed files with 17 additions and 1 deletion.
diff --git a/Libraries/LibWeb/Fetch/Headers.cpp b/Libraries/LibWeb/Fetch/Headers.cpp
@@ -9,6 +9,7 @@
 #include <LibWeb/Bindings/HeadersPrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/Fetch/Headers.h>
+#include <LibWeb/Infra/Strings.h>
 
 namespace Web::Fetch {
 
@@ -106,7 +107,7 @@ WebIDL::ExceptionOr<Optional<String>> Headers::get(String const& name_string)
 
     // 2. Return the result of getting name from this’s header list.
     auto byte_buffer = m_header_list->get(name);
-    return byte_buffer.has_value() ? MUST(String::from_utf8(*byte_buffer)) : Optional<String> {};
+    return byte_buffer.has_value() ? Infra::isomorphic_decode(*byte_buffer) : Optional<String> {};
 }
 
 // https://fetch.spec.whatwg.org/#dom-headers-getsetcookie

diff --git a/Tests/LibWeb/Text/expected/Fetch/fetch-headers-get-nonascii.txt b/Tests/LibWeb/Text/expected/Fetch/fetch-headers-get-nonascii.txt
@@ -0,0 +1,2 @@
+before-æøå-after
+before-ß-after
diff --git a/Tests/LibWeb/Text/input/Fetch/fetch-headers-get-nonascii.html b/Tests/LibWeb/Text/input/Fetch/fetch-headers-get-nonascii.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<script src="../include.js"></script>
+<script>
+    // This test ensures that the Headers get() methods can handle non-ASCII latin1 characters: code points U+0080-U+00FF.
+    test(() => {
+        const headers = new Headers({
+          "Accept": "before-æøå-after",
+          "X-Test": "before-ß-after"
+        });
+        println(headers.get("Accept"));
+        println(headers.get("X-Test"));
+    });
+</script>