119 lines
6.5 KiB
HTML
119 lines
6.5 KiB
HTML
<!DOCTYPE html>
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<!-- Inferencium - Website - Documentation - GrapheneOS hardened_malloc -->
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<!-- Copyright 2023 Jake Winters -->
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<!-- SPDX-License-Identifier: BSD-3-Clause -->
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<!-- Version: 1.0.3-alpha.5 -->
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<html lang="en">
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<head>
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<meta charset="utf-8"/>
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<title>Inferencium - Documentation - GrapheneOS hardened_malloc</title>
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<link rel="stylesheet" href=../main.css>
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<body>
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<!-- Navigation bar -->
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<div><a href="../index.html"><img src="../asset/img/logo-inferencium-no_text.png" width="110px" height="110px"></a></div>
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<div><a href="../index.html" class="title">Inferencium</a></div>
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<div><a href="../about.html">About</a></div>
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<div><a href="../contact.html">Contact</a></div>
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<div><a href="../blog.html">Blog</a></div>
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<div><a href="../documentation.html">Documentation</a></div>
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<div><a href="../source.html">Source</a></div>
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<div><a href="../key.html">Key</a></div>
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<div><a href="../changelog.html">Changelog</a></div>
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</nav>
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<section id="introduction">
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<h1 id="introduction"><a href="#introduction">Documentation - GrapheneOS hardened_malloc</a></h1>
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<p>This documentation contains instructions to use
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<a href="https://github.com/GrapheneOS/hardened_malloc">GrapheneOS hardened_malloc</a>
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memory allocator as the system's default memory allocator. These instructions apply to
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both musl and glibc C libraries on Unix-based and Unix-like systems. hardened_malloc can
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also be used per-application and/or per-user, in which case root permissions are not
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required; this documentation focuses on system-wide usage of hardened_malloc, assumes
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root privileges, and assumes the compiled library will be located in a path readable by
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all users 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>.
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</section>
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<!-- Table of contents -->
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<nav id="toc">
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<h2 id="toc"><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 id="memory_pages"><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
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amount of guard pages.</p>
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</section>
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<section id="clone_source_code">
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<h2 id="clone_source_code"><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 id="enter_local_repository"><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 id="compile"><a href="#compile">Compile hardened_malloc</a></h2>
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<p><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
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parallel performance at the expense of memory usage, or decrease memory
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usage at the expense of parallel performance, where <var>n</var> is an
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integer. Higher values prefer parallel performance, lower values prefer
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lower memory usage. The number of arenas has no impact on the security
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properties of hardened_malloc.
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<ul>
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<li>Minimum number of arenas: 1</li>
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<li>Maximum number of arenas: 256</li>
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</ul>
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<p>For extra security, <code>CONFIG_SEAL_METADATA=true</code> can be
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used in order to control whether Memory Protection Keys are used to
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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.
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Whether or not this feature is enabled, the metadata is all contained
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within an isolated memory region with high entropy random guard regions
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around it.</p>
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<p>For low-memory systems, <code>VARIANT=light</code> can be used to
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compile the light variant of hardened_malloc, which sacrifices some
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security for much less memory usage.</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 id="copy_library"><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 id="preload_on_boot"><a href="#preload_on_boot">Set System to Preload hardened_malloc on Boot</a></h2>
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<p>
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<ul>
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<li>musl-based systems: Add
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<code>export LD_PRELOAD="<var><hardened_malloc path></var>"</code>
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to <code>/etc/environment</code></li>
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<li>glibc-based systems:
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Add <code><var><hardened_malloc path></var></code> to
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<code>/etc/ld.so.preload</code></li>
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</ul>
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</p>
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</section>
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</body>
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</html>
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