MantisBT - NetSurf
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IDProjectCategoryView StatusDate SubmittedLast Update
0002874NetSurfJavascriptpublic2024-05-28 13:022024-05-28 13:02
ReporterFelix Albrigtsen 
Assigned To 
PrioritynormalSeverityminorReproducibilityalways
StatusnewResolutionopen 
PlatformGTKOSLinuxOS VersionDebian 13 Trixie
Product Version3.11 
Target VersionFixed in Version 
Fixed in CI build #
Reported in CI build #
URL of problem page
Summary0002874: Extreme resource use allowed in JavaScript
DescriptionWhen NetSurf opens the HTML file shown below, it consumes 100% of a CPU core and at least 30 GB of memory, with no safeguards, meaning it will continue consuming memory until it is eventually done, or the system's OOM killer stops NetSurf or kills another process.

The root of this issue might be in the Duktape JavaScript engine itself, and be out of scope here?

However, it seems to me to be two-parted, both that the “normalize()”-function is very inefficient on this type of input, but also that neither NetSurf nor Duktape have any limits for duration or memory usage of a function like this.

The specific example shown here uses a complex series of left and right angle brackets to confuse the normalize-function, but I find it surprising that such a short HTML file can make the OOM killer take down my entire window manager.
Steps To Reproduce- Build/Install NetSurf 3.11, for example from the Debian 13 repositories (`# apt install netsurf-gtk`)
- Enable Javascript in Preferences
- Open a page with some resource intensive JavaScript (For example, with the file ./normalize.html, run `$ netsurf-gtk file://$(pwd)/normalize.html`)

For example this HTML file:

<html>
    <head>
        <style>
            ><<>><><<>><>><<<<>><><><<>>>><<<<>><<><<>>><<><>>><>><<><<>><<>><<<<<<>>><>><><><><<>><><<<<>><>>><><><<><>>><><><><>><<<<>>>><>><><<<<<><><<<>>>>>>>>>><>>><<<<<<<<<<>>>>><><<<>>><>>>>>><>><<<<><<><>><<>><><<<>>>>>>>><<<>>>><<><<<<<><><><>><>><<<>><<<><><<<>>>>><><<>>>><>>><<<<<<<<>>><<<>>>><>>>>>><><>><><>><><>>>>><<>><<>>>><<>><><<>><><<><<>><><<<>>><<><><<<><>><<><<>><><<<<<<<<<<>><>><><<>>><>
        </style>
    </head>
<body>
    <script>
        document.head.normalize()
    </script>
</body>
</html>
Additional InformationTested with NetSurf 3.11 on Debian(testing) and NixOS (unstable).
Requires JavaScript to be enabled.
I have not tested any other platforms.
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Issue History
Date ModifiedUsernameFieldChange
2024-05-28 13:02Felix AlbrigtsenNew Issue