IDs should not be defined multiple times. Use the `<section>` elements to define the IDs rather than the headings.
126 lines
6.9 KiB
HTML
126 lines
6.9 KiB
HTML
<!DOCTYPE html>
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<!-- Inferencium - Website - Documentation - hardened_malloc -->
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<!-- Version: 3.0.0-alpha.14 -->
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<!-- Copyright 2023 Jake Winters -->
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<head>
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<meta charset="utf-8"/>
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<meta name="viewport" content="width=device-width, initial-scale=1"/>
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<title>Inferencium - Documentation - hardened_malloc</title>
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<div><a href="../documentation.xhtml">Documentation</a></div>
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</nav>
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<h1 id="hardened_malloc"><a href="#hardened_malloc">Documentation - hardened_malloc</a></h1>
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<section id="introduction">
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<p>This documentation contains instructions to use
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<a href="https://github.com/GrapheneOS/hardened_malloc">hardened_malloc</a>
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memory allocator as the system's default memory allocator. These instructions
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apply to both musl and glibc C libraries on Unix-based and Unix-like
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systems.</p>
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<p>hardened_malloc can also be used per-application and/or per-user, in which
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case root permissions are not required; this documentation focuses on
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system-wide usage of hardened_malloc, assumes root privileges, and assumes the
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compiled library will be located in a path readable and executable by all users
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of the system.</p>
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<p>For the complete hardened_malloc documentation, visit its
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<a href="https://github.com/GrapheneOS/hardened_malloc#hardened_malloc">official documentation</a>.</p>
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<p>This documentation is also available in portable AsciiDoc format in my
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<a href="https://src.inferencium.net/Inferencium/doc/src/branch/stable/security/hardened_malloc.adoc">documentation source code repository</a>.</p>
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</section>
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<nav id="toc">
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<h2><a href="#toc">Table of Contents</a></h2>
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<ul>
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<li><a href="#memory_pages">Increase Permitted Amount of Memory Pages</a></li>
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<li><a href="#clone_source_code">Clone hardened_malloc Source Code</a></li>
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<li><a href="#enter_local_repository">Enter hardened_malloc Local Git Repository</a></li>
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<li><a href="#compile">Compile hardened_malloc</a></li>
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<li><a href="#copy_library">Copy Compiled hardened_malloc Library</a></li>
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<li><a href="#preload_on_boot">Set System to Preload hardened_malloc on Boot</a></li>
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</ul>
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</nav>
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<section id="memory_pages">
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<h2><a href="#memory_pages">Increase Permitted Amount of Memory Pages</a></h2>
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<p>Add <code>vm.max_map_count = 1048576</code> to
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<code>/etc/sysctl.conf</code> to accommodate hardened_malloc's large amount of
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guard pages.</p>
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</section>
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<section id="clone_source_code">
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<h2><a href="#clone_source_code">Clone hardened_malloc Source Code</a></h2>
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<p><code>$ git clone https://github.com/GrapheneOS/hardened_malloc.git</code></p>
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</section>
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<section id="enter_local_repository">
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<h2><a href="#enter_local_repository">Enter hardened_malloc Local Git Repository</a></h2>
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<p><code>$ cd hardened_malloc/</code></p>
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</section>
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<section id="compile">
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<h2><a href="#compile">Compile hardened_malloc</a></h2>
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<p><code>$ make <var><arguments></var></code></p>
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<p><code>CONFIG_N_ARENA=<var>n</var></code> can be adjusted to increase parallel
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performance at the expense of memory usage, or decrease memory usage at the
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expense of parallel performance, where <var>n</var> is an integer. Higher values
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prefer parallel performance, whereas lower values prefer lower memory usage.
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Note that having too many arenas may cause memory fragmentation and decrease
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system performance. The number of arenas has no impact on the security
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properties of hardened_malloc.</p>
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<table align="center">
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<tr>
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<th id="arena-min">Minimum</th>
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<th id="arena-max">Maximum</th>
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<th id="arena-def">Default</th>
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</tr>
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<tr>
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<td headers="arena-min">1</td>
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<td headers="arena-max">256</td>
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<td headers="arena-def">4</td>
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</tr>
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</table>
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<p>For extra security, <code>CONFIG_SEAL_METADATA=true</code> can be used in
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order to control whether
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<a href="https://www.kernel.org/doc/html/v6.7/core-api/protection-keys.html">Memory Protection Keys</a>
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are used to disable access to all writable allocator state outside of the memory
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allocator code. It's currently disabled by default due to a significant
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performance cost for this use case on current-generation hardware. Whether or
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not this feature is enabled, the metadata is all contained within an isolated
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memory region with high-entropy random guard regions around it.</p>
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<p>For low-memory systems, <code>VARIANT=light</code> can be used to compile the
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light variant of hardened_malloc, which sacrifices some security for much less
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memory usage. This option still produces a more hardened memory allocator than
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both the default musl and glibc allocators, despite the security sacrifices over
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the full variant.</p>
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<p>For all compile-time options, see the
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<a href="https://github.com/GrapheneOS/hardened_malloc#configuration">configuration section</a>
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of hardened_malloc's extensive official documentation.</p>
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</section>
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<section id="copy_library">
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<h2><a href="#copy_library">Copy Compiled hardened_malloc Library</a></h2>
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<p><code># cp out/libhardened_malloc.so <var><target path></var></code></p>
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</section>
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<section id="preload_on_boot">
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<h2><a href="#preload_on_boot">Set System to Preload hardened_malloc on Boot</a></h2>
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<p><b>musl-based systems:</b> Add
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<code>LD_PRELOAD=<var><hardened_malloc path></var></code> to
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<code>/etc/environment</code></p>
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<p><b>glibc-based systems:</b> Add
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<code><var><hardened_malloc path></var></code> to
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<code>/etc/ld.so.preload</code></p>
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</section>
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</body>
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</html>
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