91 lines
3.7 KiB
HTML
91 lines
3.7 KiB
HTML
<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml"><head>
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<title>.</title>
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<style type="text/css">
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* { color: #000; background: #fff; max-width: 700px; }
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tt, pre { background: #dedede; color: #111; font-family: monospace;
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white-space: pre; display: block; width: 100%; }
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.indentedcode { margin-left: 2em; margin-right: 2em; }
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.codeblock {
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background: #dedede; color: #111; font-family: monospace;
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box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
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padding: 7px;
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display: block;
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}
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.indentedlist { margin-left: 2em; color: #000; }
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span { white-space: pre; }
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.text { color: #000; white-space: pre; background: #dedede; }
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.colon { color: #000; background: #dedede; }
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.note { color: #000; background: #dedede; }
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.str { color: #000; text-decoration: underline; background: #dedede; }
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.num { color: #000; background: #dedede; font-weight: bold; font-style: italic; }
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.fnum { color: #000; font-weight: bold; background: #dedede; }
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.ptr { color: #000; font-weight: bold; background: #dedede; }
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.fetch { color: #000; font-style: italic; background: #dedede; }
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.store { color: #000; font-style: italic; background: #dedede; }
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.char { color: #000; background: #dedede; }
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.inst { color: #000; background: #dedede; }
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.defer { color: #000; background: #dedede; }
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.imm { color: #000; font-weight: bold; background: #dedede; }
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.prim { color: #000; font-weight: bolder; background: #dedede; }
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.tt { white-space: pre; font-family: monospace; background: #dedede; }
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.h1, .h2, .h3, .h4 { white-space: normal; }
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.h1 { font-size: 125%; }
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.h2 { font-size: 120%; }
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.h3 { font-size: 115%; }
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.h4 { font-size: 110%; }
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.hr { display: block; height: 2px; background: #000000; }
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</style>
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</head><body>
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<p><span class="h1">Security Concerns</span>
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<br/><br/>
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The standard RETRO is not a good choice for applications
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needing to be highly secure.
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<br/><br/>
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<span class="h2">Runtime Checks</span>
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<br/><br/>
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The RETRO system performs only minimal checks. It will not
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load an image larger than the max set at build time. And
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stack over/underflow are checked for as code executes.
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<br/><br/>
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The system does not attempt to validate anything else, it's
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quite easy to crash.
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<br/><br/>
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<span class="h2">Isolation</span>
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<br/><br/>
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The VM itself and the core code is self contained. Nga does
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not make use of malloc/free, and uses only standard system
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libraries. It's possible for buffer overruns within the image
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(overwriting Nga code), but the RETRO image shouldn't leak
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into the C portions.
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<br/><br/>
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I/O presents a bigger issue. Anything involving I/O, especially
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with the <span class="tt">unix:</span> words, may be a vector for attacks.
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<br/><br/>
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<span class="h2">Future Direction</span>
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<br/><br/>
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I'm not planning to add anything to the <strong>image</strong> side as, for me,
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the performance hit due to added checks is bigger than the
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benefits.
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<br/><br/>
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The story is different on the VM side. I've already begun taking
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steps to address some of the issues, using functions that check
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for overruns with strings and doing some minor testing for these
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conditions. I will be gradually addressing the various I/O
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related extensions, though it's unlikely to ever be fully guarded
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against attacks.
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<br/><br/>
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<span class="h2">Rationale</span>
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<br/><br/>
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RETRO is, primarily, a personal system. I'm running code I wrote
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to solve problems I face. On the occasions where I run code sent
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to me by others, I read it carefully first and then run inside a
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sandboxed environment if I'm worried about anything in it.
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</p>
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</body></html>
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