1{{+bindTo:partials.standard_nacl_article}} 2 3<section id="sandbox-internals"> 4<span id="sandbox-internals-index"></span><h1 id="sandbox-internals"><span id="sandbox-internals-index"></span>Sandbox Internals</h1> 5<p>The sandbox internals documentation describes implementation details for 6Native Client sandboxing, which is also used by Portable Native 7Client. These details can be useful to reimplement a sandbox, or to 8write assembly code that follows sandboxing rules for Native Client 9(Portable Native Client does not allow platform-specific assembly code).</p> 10<p>As an implementation detail, the Native Client sandboxes described here 11are currently used by Portable Native Client to execute code on the 12corresponding machines in a safe manner. The portable bitcode contained 13in a <strong>pexe</strong> is translated to a machine-specific <strong>nexe</strong> before 14execution. This may change at a point in time: Portable Native Client 15doesn’t necessarily need these sandboxes to execute code on these 16machines. Note that the Portable Native Client compiler itself is also 17untrusted: it too runs in a Native Client sandbox described below.</p> 18<p>Native Client has sandboxes for:</p> 19<ul class="small-gap"> 20<li><a class="reference internal" href="/native-client/reference/sandbox_internals/arm-32-bit-sandbox.html#arm-32-bit-sandbox"><em>ARM 32-bit</em></a>.</li> 21<li>x86-32: the original design is described in <a class="reference external" href="http://research.google.com/pubs/archive/34913.pdf">Native Client: A Sandbox 22for Portable, Untrusted x86 Native Code</a>, the current 23design has changed slightly since then.</li> 24<li><a class="reference internal" href="/native-client/reference/sandbox_internals/x86-64-sandbox.html#x86-64-sandbox"><em>x86-64</em></a>.</li> 25<li>MIPS32, described in the <a class="reference external" href="https://code.google.com/p/nativeclient/issues/attachmentText?id=2275&aid=22750018000&name=native-client-mips-0.4.txt">overview of Native Client for MIPS</a>, 26and <a class="reference external" href="https://code.google.com/p/nativeclient/issues/detail?id=2275">bug 2275</a>.</li> 27</ul> 28</section> 29 30{{/partials.standard_nacl_article}} 31