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diff --git a/static/usage.html b/static/usage.html index 376597d9..90257161 100644 --- a/static/usage.html +++ b/static/usage.html @@ -40,6 +40,71 @@ <a href="#auditor">¶</a> </h2> <p>See the <a href="https://attestation.app/tutorial">tutorial page on the site for the attestation sub-project</a>.</p> + + <h2 id="default-connections"> + Default connections + <a href="#default-connections">¶</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://seamlessupdate.app/DEVICE-CHANNEL approximately once every four hours + when connected to a permitted network for updates.</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.</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> + </li> + <li> + <p>DNS connectivity and functionality tests</p> + </li> + <li> + <p>DNS resolution for other connections</p> + </li> + </ul> + + <p>Similar connectivity checks are also performed by the hardened Chromium browser (Vanadium).</p> </div> <footer> <a href="/"><img src="https://grapheneos.org/logo.png" width="512" height="512" alt=""/>GrapheneOS</a> |