From b6d9491f56e29da9bf4af874d591af28d5a14bb6 Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Mon, 17 Feb 2020 00:18:04 -0500
Subject: move default connections to FAQ

---
 static/faq.html | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

(limited to 'static/faq.html')

diff --git a/static/faq.html b/static/faq.html
index 0c26c3a8..7b0c1867 100644
--- a/static/faq.html
+++ b/static/faq.html
@@ -61,6 +61,8 @@
                     <ul>
                         <li><a href="#hardware-identifiers">Can apps access hardware
                         identifiers?</a></li>
+                        <li><a href="#default-connections">Which connections do the OS and
+                        bundled apps make by default?</a></li>
                     </ul>
                 </li>
             </ul>
@@ -206,6 +208,88 @@
             <p>GrapheneOS only makes a small change to remove a legacy form of access to the
             serial number by legacy apps, which was still around for compatibility.</p>
 
+            <h2 id="default-connections">
+                <a href="#default-connections">What kind of connections do the OS and bundled apps
+                make by default?</a>
+            </h2>
+
+            <p>GrapheneOS makes connections to the outside world to test connectivity, detect
+            captive portals and download updates. No data varying per user / installation is sent
+            in these connections. There aren't analytics / telemetry in GrapheneOS.</p>
+
+            <p>The expected default connections by GrapheneOS (including all base system apps) are
+            the following:</p>
+
+            <ul>
+                <li>
+                    <p>The GrapheneOS Updater app fetches update metadata from
+                    https://releases.grapheneos.org/DEVICE-CHANNEL approximately once every four hours
+                    when connected to a permitted network for updates.</p>
+                    <p>Once an update is available, it tries to download
+                    https://releases.grapheneos.org/DEVICE-incremental-OLD_VERSION-NEW_VERSION.zip
+                    for a delta update, and then falls back to
+                    https://releases.grapheneos.org/DEVICE-ota_update-NEW_VERSION.zip.</p>
+                    <p>No query / data is sent to the server, so the only information leaked to it
+                    are the variables in these 3 URLs (device, channel, current version) which is
+                    necessary to obtain the update.</p>
+                    <p>Users can control which types of connections the Updater app will use, and
+                    although it's strongly recommended to always leave it enabled it can be
+                    disabled.</p>
+                </li>
+                <li>
+                    <p>On devices with a Qualcomm baseband (which provides GPS), when location
+                    functionality is being used,
+                    <a href="https://en.wikipedia.org/wiki/GPS_signals#Almanac">GPS almanacs</a>
+                    are downloaded from https://xtrapath1.izatcloud.net/xtra3grc.bin,
+                    https://xtrapath2.izatcloud.net/xtra3grc.bin or
+                    https://xtrapath3.izatcloud.net/xtra3grc.bin. GrapheneOS has modified all
+                    references to these servers to use HTTPS rather than a mix of HTTP and HTTPS.
+                    No query / data is sent to the server.</p>
+                </li>
+                <li>
+                    <p>Connectivity checks designed to mimic a web browser user agent are performed
+                    by using HTTP and HTTPS to fetch standard URLs generating an HTTP 204 status
+                    code. This is used to detect when internet connectivity is lost on a network,
+                    which triggers fallback to other available networks if possible. These checks
+                    are designed to detect and handle captive portals which substitute the
+                    expected empty 204 response with their own web page. These need use a very
+                    common domain and URL in order to bypass whitelisting systems only permitting
+                    access to common domains / URLs so a domain like grapheneos.org would likely
+                    be inadequate. GrapheneOS leaves these set to the standard four URLs to blend
+                    into the crowd of billions of other Android devices with and without Google
+                    Mobile Services performing the same empty GET requests. For privacy reasons,
+                    it isn't desirable to stand out from the crowd and changing these URLs or even
+                    disabling the feature will likely reduce your privacy by giving your device a
+                    more unique fingerprint. GrapheneOS aims to appear like any other common
+                    mobile device on the network.</p>
+                    <ul>
+                        <li>HTTPS: https://www.google.com/generate_204</li>
+                        <li>HTTP: http://connectivitycheck.gstatic.com/generate_204</li>
+                        <li>HTTP fallback: http://www.google.com/gen_204</li>
+                        <li>HTTP other fallback: http://play.googleapis.com/generate_204</li>
+                    </ul>
+                    <p>Standard AOSP user agent for the GET request:</p>
+                    <p>Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.32 Safari/537.36</p>
+                    <p>No query / data is sent and the response is unused beyond checking the response code.</p>
+                    <p>Similar connectivity checks are also performed by Vanadium.</p>
+                </li>
+                <li>
+                    <p>DNS connectivity and functionality tests</p>
+                </li>
+                <li>
+                    <p>DNS resolution for other connections</p>
+                </li>
+                <li>
+                    <p>An HTTPS connection is made to https://time.grapheneos.org/ to update the
+                    time from the date header field. This is a full replacement of Android's
+                    standard network time update implementation, which uses the cellular network
+                    when available with a fallback to SNTP when it's not available. This can be
+                    disabled with the toggle at Settings ➔ System ➔ Date &amp; time ➔ Use
+                    network-provided time. The time zone is still obtained directly via the time
+                    zone provided by the mobile network when available.</p>
+                </li>
+            </ul>
+
         </div>
         <footer>
             <a href="/"><img src="https://grapheneos.org/logo.png" width="512" height="512" alt=""/>GrapheneOS</a>
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