LibWebView: Protect URL highlighting against partially-typed URLs

The current helpers assume that a valid URL is a full URL (i.e. contains
the "://" separator between the scheme and domain). This isn't true, as
"file:" alone is parsed as a valid URL.

We must also avoid simply searching for the parsed public suffix in the
original URL string. For example, "com" is a public suffix. If we search
for that in the URL "com.com", we will think the public suffix starts at
index 0.

Meta/Lagom/CMakeLists.txt

@@ -651,6 +651,7 @@ if (BUILD_LAGOM)
             LibTimeZone
             LibUnicode
             LibVideo
+            LibWebView
             LibXML
         )
         if (ENABLE_LAGOM_LIBWEB)

Tests/CMakeLists.txt

@@ -26,6 +26,7 @@ add_subdirectory(LibUnicode)
 add_subdirectory(LibVideo)
 add_subdirectory(LibWasm)
 add_subdirectory(LibWeb)
+add_subdirectory(LibWebView)
 add_subdirectory(LibXML)
 add_subdirectory(LibCrypto)
 add_subdirectory(LibTLS)

Tests/LibWebView/CMakeLists.txt

@@ -0,0 +1,7 @@
+set(TEST_SOURCES
+    TestWebViewURL.cpp
+)
+
+foreach(source IN LISTS TEST_SOURCES)
+    serenity_test("${source}" LibWebView LIBS LibWebView)
+endforeach()

Tests/LibWebView/TestWebViewURL.cpp

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibTest/TestCase.h>
+#include <LibWebView/URL.h>
+
+static void compare_url_parts(StringView url, WebView::URLParts const& expected)
+{
+    auto result = WebView::break_url_into_parts(url);
+    VERIFY(result.has_value());
+
+    EXPECT_EQ(result->scheme_and_subdomain, expected.scheme_and_subdomain);
+    EXPECT_EQ(result->effective_tld_plus_one, expected.effective_tld_plus_one);
+    EXPECT_EQ(result->remainder, expected.remainder);
+}
+
+TEST_CASE(invalid_url)
+{
+    EXPECT(!WebView::break_url_into_parts(""sv).has_value());
+    EXPECT(!WebView::break_url_into_parts(":"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts(":/"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("://"sv).has_value());
+
+    EXPECT(!WebView::break_url_into_parts("f"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("fi"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("fil"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("file"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("file:"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("file:/"sv).has_value());
+
+    EXPECT(!WebView::break_url_into_parts("h"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("ht"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("htt"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("http"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("http:"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("http:/"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("http://"sv).has_value());
+
+    EXPECT(!WebView::break_url_into_parts("https"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("https:"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("https:/"sv).has_value());
+    EXPECT(!WebView::break_url_into_parts("https://"sv).has_value());
+}
+
+TEST_CASE(file_url)
+{
+    compare_url_parts("file://"sv, { "file://"sv, ""sv, {} });
+    compare_url_parts("file://a"sv, { "file://"sv, "a"sv, {} });
+    compare_url_parts("file:///a"sv, { "file://"sv, "/a"sv, {} });
+    compare_url_parts("file:///abc"sv, { "file://"sv, "/abc"sv, {} });
+}
+
+TEST_CASE(http_url)
+{
+    compare_url_parts("http://a"sv, { "http://"sv, "a"sv, {} });
+    compare_url_parts("http://abc"sv, { "http://"sv, "abc"sv, {} });
+    compare_url_parts("http://com"sv, { "http://"sv, "com"sv, {} });
+    compare_url_parts("http://abc."sv, { "http://"sv, "abc."sv, {} });
+    compare_url_parts("http://abc.c"sv, { "http://"sv, "abc.c"sv, {} });
+    compare_url_parts("http://abc.com"sv, { "http://"sv, "abc.com"sv, {} });
+    compare_url_parts("http://abc.com."sv, { "http://"sv, "abc.com."sv, {} });
+    compare_url_parts("http://abc.com."sv, { "http://"sv, "abc.com."sv, {} });
+    compare_url_parts("http://abc.com.org"sv, { "http://abc."sv, "com.org"sv, {} });
+    compare_url_parts("http://abc.com.org.gov"sv, { "http://abc.com."sv, "org.gov"sv, {} });
+
+    compare_url_parts("http://abc/path"sv, { "http://"sv, "abc"sv, "/path"sv });
+    compare_url_parts("http://abc#anchor"sv, { "http://"sv, "abc"sv, "#anchor"sv });
+    compare_url_parts("http://abc?query"sv, { "http://"sv, "abc"sv, "?query"sv });
+
+    compare_url_parts("http://abc.def.com"sv, { "http://abc."sv, "def.com"sv, {} });
+    compare_url_parts("http://abc.def.com/path"sv, { "http://abc."sv, "def.com"sv, "/path"sv });
+    compare_url_parts("http://abc.def.com#anchor"sv, { "http://abc."sv, "def.com"sv, "#anchor"sv });
+    compare_url_parts("http://abc.def.com?query"sv, { "http://abc."sv, "def.com"sv, "?query"sv });
+}

Userland/Libraries/LibWebView/URL.cpp

@@ -107,27 +107,35 @@ static URLParts break_file_url_into_parts(URL const& url, StringView url_string)
 
 static URLParts break_web_url_into_parts(URL const& url, StringView url_string)
 {
-    auto host = MUST(url.serialized_host());
+    auto scheme = url_string.substring_view(0, url.scheme().bytes_as_string_view().length() + "://"sv.length());
+    auto url_without_scheme = url_string.substring_view(scheme.length());
 
-    auto public_suffix = get_public_suffix(host);
-    if (!public_suffix.has_value())
-        return {};
+    StringView domain;
+    StringView remainder;
 
-    auto public_suffix_start = url_string.find(*public_suffix);
-    auto public_suffix_end = public_suffix_start.value() + public_suffix->bytes_as_string_view().length();
+    if (auto index = url_without_scheme.find_any_of("/?#"sv); index.has_value()) {
+        domain = url_without_scheme.substring_view(0, *index);
+        remainder = url_without_scheme.substring_view(*index);
+    } else {
+        domain = url_without_scheme;
+    }
 
-    auto scheme_and_subdomain = url_string.substring_view(0, *public_suffix_start);
-    scheme_and_subdomain = scheme_and_subdomain.trim("."sv, TrimMode::Right);
+    auto public_suffix = get_public_suffix(domain);
+    if (!public_suffix.has_value() || !domain.ends_with(*public_suffix))
+        return { scheme, domain, remainder };
 
-    if (auto index = scheme_and_subdomain.find_last('.'); index.has_value())
-        scheme_and_subdomain = scheme_and_subdomain.substring_view(0, *index + 1);
-    else
-        scheme_and_subdomain = scheme_and_subdomain.substring_view(0, url.scheme().bytes_as_string_view().length() + "://"sv.length());
+    auto subdomain = domain.substring_view(0, domain.length() - public_suffix->bytes_as_string_view().length());
+    subdomain = subdomain.trim("."sv, TrimMode::Right);
 
-    auto effective_tld_plus_one = url_string.substring_view(scheme_and_subdomain.length(), public_suffix_end - scheme_and_subdomain.length());
-    auto remainder = url_string.substring_view(public_suffix_end);
+    if (auto index = subdomain.find_last('.'); index.has_value()) {
+        subdomain = subdomain.substring_view(0, *index + 1);
+        domain = domain.substring_view(subdomain.length());
+    } else {
+        subdomain = {};
+    }
 
-    return URLParts { scheme_and_subdomain, effective_tld_plus_one, remainder };
+    auto scheme_and_subdomain = url_string.substring_view(0, scheme.length() + subdomain.length());
+    return { scheme_and_subdomain, domain, remainder };
 }
 
 Optional<URLParts> break_url_into_parts(StringView url_string)
@@ -136,6 +144,10 @@ Optional<URLParts> break_url_into_parts(StringView url_string)
     if (!url.is_valid())
         return {};
 
+    auto scheme_length = url.scheme().bytes_as_string_view().length();
+    if (!url_string.substring_view(scheme_length).starts_with("://"sv))
+        return {};
+
     if (url.scheme() == "file"sv)
         return break_file_url_into_parts(url, url_string);
     if (url.scheme().is_one_of("http"sv, "https"sv, "gemini"sv))