Add a couple extra sentences to the two design requirements sections, describing their purpose.
Mike Perry commited on 2011-10-02 09:42:56
Zeige 1 geänderte Dateien mit 14 Einfügungen und 10 Löschungen.
- projects/torbrowser/design/index.html.en 3653fb94c..6a8ce88cf
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<?xml version="1.0" encoding="UTF-8"?> |
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> |
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-<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>The Design and Implementation of the Tor Browser [DRAFT]</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /></head><body><div class="article" title="The Design and Implementation of the Tor Browser [DRAFT]"><div class="titlepage"><div><div><h2 class="title"><a id="design"></a>The Design and Implementation of the Tor Browser [DRAFT]</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Mike</span> <span class="surname">Perry</span></h3><div class="affiliation"><div class="address"><p><code class="email"><<a class="email" href="mailto:mikeperry#torproject org">mikeperry#torproject org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Erinn</span> <span class="surname">Clark</span></h3><div class="affiliation"><div class="address"><p><code class="email"><<a class="email" href="mailto:erinn_torproject\org">erinn_torproject\org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Steven</span> <span class="surname">Murdoch</span></h3><div class="affiliation"><div class="address"><p><code class="email"><<a class="email" href="mailto:sjmurdoch#torproject\org">sjmurdoch#torproject\org</a>></code></p></div></div></div></div><div><p class="pubdate">Sep 29 2011</p></div></div><hr /></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="#id2555242">1. Introduction</a></span></dt><dd><dl><dt><span class="sect2"><a href="#adversary">1.1. Adversary Model</a></span></dt></dl></dd><dt><span class="sect1"><a href="#DesignRequirements">2. Design Requirements and Philosophy</a></span></dt><dd><dl><dt><span class="sect2"><a href="#security">2.1. Security Requirements</a></span></dt><dt><span class="sect2"><a href="#privacy">2.2. Privacy Requirements</a></span></dt><dt><span class="sect2"><a href="#philosophy">2.3. Philosophy</a></span></dt></dl></dd><dt><span class="sect1"><a href="#Implementation">3. Implementation</a></span></dt><dd><dl><dt><span class="sect2"><a href="#proxy-obedience">3.1. Proxy Obedience</a></span></dt><dt><span class="sect2"><a href="#state-separation">3.2. State Separation</a></span></dt><dt><span class="sect2"><a href="#disk-avoidance">3.3. Disk Avoidance</a></span></dt><dt><span class="sect2"><a href="#app-data-isolation">3.4. Application Data Isolation</a></span></dt><dt><span class="sect2"><a href="#identifier-linkability">3.5. Cross-Domain Identifier Unlinkability</a></span></dt><dt><span class="sect2"><a href="#fingerprinting-linkability">3.6. Cross-Domain Fingerprinting Unlinkability</a></span></dt><dt><span class="sect2"><a href="#new-identity">3.7. Long-Term Unlinkability via "New Identity" button</a></span></dt><dt><span class="sect2"><a href="#click-to-play">3.8. Click-to-play for plugins and invasive content</a></span></dt><dt><span class="sect2"><a href="#firefox-patches">3.9. Description of Firefox Patches</a></span></dt></dl></dd><dt><span class="sect1"><a href="#Packaging">4. Packaging</a></span></dt><dd><dl><dt><span class="sect2"><a href="#build-security">4.1. Build Process Security</a></span></dt><dt><span class="sect2"><a href="#addons">4.2. External Addons</a></span></dt><dt><span class="sect2"><a href="#prefs">4.3. Pref Changes</a></span></dt><dt><span class="sect2"><a href="#update-mechanism">4.4. Update Security</a></span></dt></dl></dd><dt><span class="sect1"><a href="#Testing">5. Testing</a></span></dt><dd><dl><dt><span class="sect2"><a href="#SingleStateTesting">5.1. Single state testing</a></span></dt></dl></dd></dl></div><div class="sect1" title="1. Introduction"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="id2555242"></a>1. Introduction</h2></div></div></div><p> |
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+<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>The Design and Implementation of the Tor Browser [DRAFT]</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /></head><body><div class="article" title="The Design and Implementation of the Tor Browser [DRAFT]"><div class="titlepage"><div><div><h2 class="title"><a id="design"></a>The Design and Implementation of the Tor Browser [DRAFT]</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Mike</span> <span class="surname">Perry</span></h3><div class="affiliation"><div class="address"><p><code class="email"><<a class="email" href="mailto:mikeperry#torproject org">mikeperry#torproject org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Erinn</span> <span class="surname">Clark</span></h3><div class="affiliation"><div class="address"><p><code class="email"><<a class="email" href="mailto:erinn_torproject\org">erinn_torproject\org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Steven</span> <span class="surname">Murdoch</span></h3><div class="affiliation"><div class="address"><p><code class="email"><<a class="email" href="mailto:sjmurdoch#torproject\org">sjmurdoch#torproject\org</a>></code></p></div></div></div></div><div><p class="pubdate">Sep 29 2011</p></div></div><hr /></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="#id2974058">1. Introduction</a></span></dt><dd><dl><dt><span class="sect2"><a href="#adversary">1.1. Adversary Model</a></span></dt></dl></dd><dt><span class="sect1"><a href="#DesignRequirements">2. Design Requirements and Philosophy</a></span></dt><dd><dl><dt><span class="sect2"><a href="#security">2.1. Security Requirements</a></span></dt><dt><span class="sect2"><a href="#privacy">2.2. Privacy Requirements</a></span></dt><dt><span class="sect2"><a href="#philosophy">2.3. Philosophy</a></span></dt></dl></dd><dt><span class="sect1"><a href="#Implementation">3. Implementation</a></span></dt><dd><dl><dt><span class="sect2"><a href="#proxy-obedience">3.1. Proxy Obedience</a></span></dt><dt><span class="sect2"><a href="#state-separation">3.2. State Separation</a></span></dt><dt><span class="sect2"><a href="#disk-avoidance">3.3. Disk Avoidance</a></span></dt><dt><span class="sect2"><a href="#app-data-isolation">3.4. Application Data Isolation</a></span></dt><dt><span class="sect2"><a href="#identifier-linkability">3.5. Cross-Domain Identifier Unlinkability</a></span></dt><dt><span class="sect2"><a href="#fingerprinting-linkability">3.6. Cross-Domain Fingerprinting Unlinkability</a></span></dt><dt><span class="sect2"><a href="#new-identity">3.7. Long-Term Unlinkability via "New Identity" button</a></span></dt><dt><span class="sect2"><a href="#click-to-play">3.8. Click-to-play for plugins and invasive content</a></span></dt><dt><span class="sect2"><a href="#firefox-patches">3.9. Description of Firefox Patches</a></span></dt></dl></dd><dt><span class="sect1"><a href="#Packaging">4. Packaging</a></span></dt><dd><dl><dt><span class="sect2"><a href="#build-security">4.1. Build Process Security</a></span></dt><dt><span class="sect2"><a href="#addons">4.2. External Addons</a></span></dt><dt><span class="sect2"><a href="#prefs">4.3. Pref Changes</a></span></dt><dt><span class="sect2"><a href="#update-mechanism">4.4. Update Security</a></span></dt></dl></dd><dt><span class="sect1"><a href="#Testing">5. Testing</a></span></dt><dd><dl><dt><span class="sect2"><a href="#SingleStateTesting">5.1. Single state testing</a></span></dt></dl></dd></dl></div><div class="sect1" title="1. Introduction"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="id2974058"></a>1. Introduction</h2></div></div></div><p> |
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| 4 | 4 |
|
| 5 | 5 |
This document describes the <a class="link" href="#adversary" title="1.1. Adversary Model">adversary model</a>, |
| 6 | 6 |
<a class="link" href="#DesignRequirements" title="2. Design Requirements and Philosophy">design requirements</a>, |
| ... | ... |
@@ -191,7 +191,9 @@ maintain and/or restore privacy properties to our users. |
| 191 | 191 |
|
| 192 | 192 |
The security requirements are primarily concerned with ensuring the safe use |
| 193 | 193 |
of Tor. Violations in these properties typically result in serious risk for |
| 194 |
-the user in terms of immediate deanonymization and/or observability. |
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+the user in terms of immediate deanonymization and/or observability. With |
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+respect to platform support, security requirements are the minimum properties |
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+in order for Tor to support the use of a web client platform. |
|
| 195 | 197 |
|
| 196 | 198 |
</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><span class="command"><strong>Proxy Obedience</strong></span><p>The browser |
| 197 | 199 |
MUST NOT bypass Tor proxy settings for any content.</p></li><li class="listitem"><span class="command"><strong>State Separation</strong></span><p>The browser MUST NOT provide any stored state to the content window |
| ... | ... |
@@ -210,8 +212,10 @@ MUST BE documented. |
| 210 | 212 |
</p></li><li class="listitem"><span class="command"><strong>Update Safety</strong></span><p>The browser SHOULD NOT perform unsafe updates or upgrades.</p></li></ol></div></div><div class="sect2" title="2.2. Privacy Requirements"><div class="titlepage"><div><div><h3 class="title"><a id="privacy"></a>2.2. Privacy Requirements</h3></div></div></div><p> |
| 211 | 213 |
|
| 212 | 214 |
The privacy requirements are primarily concerned with reducing linkability: |
| 213 |
-the ability for a user's activity on one site to be linked with their |
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| 214 |
-activity on another site without their knowledge or explicit consent. |
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+the ability for a user's activity on one site to be linked with their activity |
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+on another site without their knowledge or explicit consent. With respect to |
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+platform support, privacy requirements are the set of properties that cause us |
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| 218 |
+to prefer one platform over another. |
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| 215 | 219 |
|
| 216 | 220 |
</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><span class="command"><strong>Cross-Domain Identifier Unlinkability</strong></span><p> |
| 217 | 221 |
|
| ... | ... |
@@ -367,13 +371,13 @@ launch a helper app. |
| 367 | 371 |
Tor Browser State is separated from existing browser state through use of a |
| 368 | 372 |
custom Firefox profile. Furthermore, plugins are disabled, which prevents |
| 369 | 373 |
Flash cookies from leaking from a pre-existing Flash directory. |
| 370 |
- </p></div><div class="sect2" title="3.3. Disk Avoidance"><div class="titlepage"><div><div><h3 class="title"><a id="disk-avoidance"></a>3.3. Disk Avoidance</h3></div></div></div><div class="sect3" title="Design Goal:"><div class="titlepage"><div><div><h4 class="title"><a id="id2561771"></a>Design Goal:</h4></div></div></div><div class="blockquote"><blockquote class="blockquote"> |
|
| 374 |
+ </p></div><div class="sect2" title="3.3. Disk Avoidance"><div class="titlepage"><div><div><h3 class="title"><a id="disk-avoidance"></a>3.3. Disk Avoidance</h3></div></div></div><div class="sect3" title="Design Goal:"><div class="titlepage"><div><div><h4 class="title"><a id="id2980587"></a>Design Goal:</h4></div></div></div><div class="blockquote"><blockquote class="blockquote"> |
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| 371 | 375 |
Tor Browser should optionally prevent all disk records of browser activity. |
| 372 | 376 |
The user should be able to optionally enable URL history and other history |
| 373 | 377 |
features if they so desire. Once we <a class="ulink" href="https://trac.torproject.org/projects/tor/ticket/3100" target="_top">simplify the |
| 374 | 378 |
preferences interface</a>, we will likely just enable Private Browsing |
| 375 | 379 |
mode by default to handle this goal. |
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- </blockquote></div></div><div class="sect3" title="Implementation Status:"><div class="titlepage"><div><div><h4 class="title"><a id="id2587990"></a>Implementation Status:</h4></div></div></div><div class="blockquote"><blockquote class="blockquote"> |
|
| 380 |
+ </blockquote></div></div><div class="sect3" title="Implementation Status:"><div class="titlepage"><div><div><h4 class="title"><a id="id3006806"></a>Implementation Status:</h4></div></div></div><div class="blockquote"><blockquote class="blockquote"> |
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| 377 | 381 |
For now, Tor Browser blocks write access to the disk through Torbutton |
| 378 | 382 |
using several Firefox preferences. |
| 379 | 383 |
|
| ... | ... |
@@ -439,7 +443,7 @@ to clear and/or block them, possibly with a context-menu option to drill down |
| 439 | 443 |
into specific types of state. An exmaple of this simplifcation can be seen in |
| 440 | 444 |
Figure 1. |
| 441 | 445 |
|
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- </p><div class="figure"><a id="id2543955"></a><p class="title"><b>Figure 1. Improving the Privacy UI</b></p><div class="figure-contents"><div class="mediaobject" align="center"><img src="CookieManagers.png" align="middle" alt="Improving the Privacy UI" /></div><div class="caption"><p></p> |
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+ </p><div class="figure"><a id="id2962771"></a><p class="title"><b>Figure 1. Improving the Privacy UI</b></p><div class="figure-contents"><div class="mediaobject" align="center"><img src="CookieManagers.png" align="middle" alt="Improving the Privacy UI" /></div><div class="caption"><p></p> |
|
| 443 | 447 |
|
| 444 | 448 |
On the left is the standard Firefox cookie manager. On the right is a mock-up |
| 445 | 449 |
of how isolating identifiers to the URL bar domain might simplify the privacy |
| ... | ... |
@@ -760,11 +764,11 @@ Currently we simply disable WebGL. |
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</p></li></ol></div></div><div class="sect2" title="3.7. Long-Term Unlinkability via "New Identity" button"><div class="titlepage"><div><div><h3 class="title"><a id="new-identity"></a>3.7. Long-Term Unlinkability via "New Identity" button</h3></div></div></div><p> |
| 761 | 765 |
In order to avoid long-term linkability, we provide a "New Identity" context |
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menu option in Torbutton. |
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- </p><div class="sect3" title="Design Goal:"><div class="titlepage"><div><div><h4 class="title"><a id="id2573074"></a>Design Goal:</h4></div></div></div><div class="blockquote"><blockquote class="blockquote"> |
|
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+ </p><div class="sect3" title="Design Goal:"><div class="titlepage"><div><div><h4 class="title"><a id="id2991890"></a>Design Goal:</h4></div></div></div><div class="blockquote"><blockquote class="blockquote"> |
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| 764 | 768 |
|
| 765 | 769 |
All linkable identifiers and browser state should be cleared by this feature. |
| 766 | 770 |
|
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- </blockquote></div></div><div class="sect3" title="Implementation Status:"><div class="titlepage"><div><div><h4 class="title"><a id="id2588627"></a>Implementation Status:</h4></div></div></div><div class="blockquote"><blockquote class="blockquote"> |
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+ </blockquote></div></div><div class="sect3" title="Implementation Status:"><div class="titlepage"><div><div><h4 class="title"><a id="id3007443"></a>Implementation Status:</h4></div></div></div><div class="blockquote"><blockquote class="blockquote"> |
|
| 768 | 772 |
First, Torbutton disables |
| 769 | 773 |
all open tabs and windows via nsIContentPolicy blocking, and then closes each |
| 770 | 774 |
tab and window. The extra step for blocking tabs is done as a precaution to |
| ... | ... |
@@ -865,7 +869,7 @@ ruin our day, and censorship filters). Hence we rolled our own. |
| 865 | 869 |
This patch prevents random URLs from being inserted into content-prefs.sqllite in |
| 866 | 870 |
the profile directory as content prefs change (includes site-zoom and perhaps |
| 867 | 871 |
other site prefs?). |
| 868 |
- </p></li></ol></div></div></div><div class="sect1" title="4. Packaging"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Packaging"></a>4. Packaging</h2></div></div></div><p> </p><div class="sect2" title="4.1. Build Process Security"><div class="titlepage"><div><div><h3 class="title"><a id="build-security"></a>4.1. Build Process Security</h3></div></div></div><p> </p></div><div class="sect2" title="4.2. External Addons"><div class="titlepage"><div><div><h3 class="title"><a id="addons"></a>4.2. External Addons</h3></div></div></div><p> </p><div class="sect3" title="Included Addons"><div class="titlepage"><div><div><h4 class="title"><a id="id2555211"></a>Included Addons</h4></div></div></div></div><div class="sect3" title="Excluded Addons"><div class="titlepage"><div><div><h4 class="title"><a id="id2581163"></a>Excluded Addons</h4></div></div></div></div><div class="sect3" title="Dangerous Addons"><div class="titlepage"><div><div><h4 class="title"><a id="id2587402"></a>Dangerous Addons</h4></div></div></div></div></div><div class="sect2" title="4.3. Pref Changes"><div class="titlepage"><div><div><h3 class="title"><a id="prefs"></a>4.3. Pref Changes</h3></div></div></div><p> </p></div><div class="sect2" title="4.4. Update Security"><div class="titlepage"><div><div><h3 class="title"><a id="update-mechanism"></a>4.4. Update Security</h3></div></div></div><p> </p></div></div><div class="sect1" title="5. Testing"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Testing"></a>5. Testing</h2></div></div></div><p> |
|
| 872 |
+ </p></li></ol></div></div></div><div class="sect1" title="4. Packaging"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Packaging"></a>4. Packaging</h2></div></div></div><p> </p><div class="sect2" title="4.1. Build Process Security"><div class="titlepage"><div><div><h3 class="title"><a id="build-security"></a>4.1. Build Process Security</h3></div></div></div><p> </p></div><div class="sect2" title="4.2. External Addons"><div class="titlepage"><div><div><h3 class="title"><a id="addons"></a>4.2. External Addons</h3></div></div></div><p> </p><div class="sect3" title="Included Addons"><div class="titlepage"><div><div><h4 class="title"><a id="id2974027"></a>Included Addons</h4></div></div></div></div><div class="sect3" title="Excluded Addons"><div class="titlepage"><div><div><h4 class="title"><a id="id2999979"></a>Excluded Addons</h4></div></div></div></div><div class="sect3" title="Dangerous Addons"><div class="titlepage"><div><div><h4 class="title"><a id="id3006218"></a>Dangerous Addons</h4></div></div></div></div></div><div class="sect2" title="4.3. Pref Changes"><div class="titlepage"><div><div><h3 class="title"><a id="prefs"></a>4.3. Pref Changes</h3></div></div></div><p> </p></div><div class="sect2" title="4.4. Update Security"><div class="titlepage"><div><div><h3 class="title"><a id="update-mechanism"></a>4.4. Update Security</h3></div></div></div><p> </p></div></div><div class="sect1" title="5. Testing"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Testing"></a>5. Testing</h2></div></div></div><p> |
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| 869 | 873 |
|
| 870 | 874 |
The purpose of this section is to cover all the known ways that Tor browser |
| 871 | 875 |
security can be subverted from a penetration testing perspective. The hope |
| 872 | 876 |