update Qualcomm PSDS (XTRA) information

This commit is contained in:
Daniel Micay 2023-05-06 00:25:47 -04:00
parent a4d47678ef
commit ee561d858d
2 changed files with 25 additions and 35 deletions

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@ -767,16 +767,11 @@
<article id="default-connections">
<h3><a href="#default-connections">What kind of connections do the OS and bundled apps make by default?</a></h3>
<p>GrapheneOS makes connections to the outside world to test connectivity, detect
captive portals and download updates. No data varying per user / installation / device
is sent in these connections. There aren't analytics / telemetry in GrapheneOS.</p>
<p>On 6th and 7th generation Pixels, GrapheneOS only connects to GrapheneOS
servers by default. On 4th and 5th generation Pixels, there's a single
non-GrapheneOS connection to download static files from a Qualcomm service
(PSDS, referred to as XTRA by Qualcomm) hosted on Amazon Web Services which
we're in the process of phasing out. We've already made changes to resolve a
serious privacy issue with this Qualcomm service.</p>
<p>GrapheneOS makes connections to the outside world to test connectivity,
detect captive portals and download updates. No data varying per user /
installation / device is sent in these connections. There aren't analytics /
telemetry in GrapheneOS. By default, remote connections are only made to
GrapheneOS services and the network provided DNS resolvers.</p>
<p>Make sure to read the <a href="#other-connections">other connections</a>
section below this one too which covers non-default connections triggered by
@ -870,33 +865,27 @@
<p>On 4th and 5th generation Pixels (which use a Qualcomm baseband
providing cellular, Wi-Fi, Bluetooth and GNSS in separate sandboxes),
almanacs are downloaded from
https://path1.xtracloud.net/xtra3grcej.bin
https://path2.xtracloud.net/xtra3grcej.bin,
https://path3.xtracloud.net/xtra3grcej.bin,
https://qualcomm.psds.grapheneos.org/xtra3Mgrbeji.bin which is a cache
of Qualcomm's data. Alternatively, the standard servers can be enabled
in the Settings app which will use
https://path1.xtracloud.net/xtra3Mgrbeji.bin,
https://path2.xtracloud.net/xtra3Mgrbeji.bin and
https://path3.xtracloud.net/xtra3Mgrbeji.bin which currently (as of
October 2022) are hosted via Amazon Web Services. xtra-daemon sets a
custom User-Agent header with information on the device. GrapheneOS
stops it from including any unique hardware identifiers and is in the
process of entirely disabling the User-Agent header to avoid sending
the device model, manufacturer, etc. to Qualcomm. We're hosting a
similar PSDS cache for Qualcomm PSDS data and plan to use it by
default once we implement support for switching between our servers
and Qualcomm's servers via the same toggle we use for the newer
Broadcomm GNSS Pixels.</p>
https://path3.xtracloud.net/xtra3Mgrbeji.bin. GrapheneOS improves the
privacy of Qualcomm PSDS (XTRA) by removing the User-Agent header
normally containing an SoC serial number (unique hardware identifier),
random ID and information on the phone including manufacturer, brand
and model. We also always fetch the most complete XTRA database variant
(xtra3Mgrbeji.bin) instead of model/carrier/region dependent variants
to avoid leaking a small amount of information based on the database
variant.</p>
<p>Qualcomm Snapdragon SoC devices also fetch time from
time.xtracloud.net via NTP rather than using the OS time. Stock Pixel
OS overrides this to time.google.com but we use the standard server
like other Snapdragon devices. It's technically incorrect to use the
time.google.com server for this due to non-standard leap second
smearing not expected by the Qualcomm GNSS implementation. This could
be avoided by using OS time instead but Qualcomm built it this way to
avoid GNSS-based location being crippled by having time set wrong in
the OS.</p>
<p></p>
<p>Qualcomm Snapdragon SoC devices also fetch time via NTP from
time.grapheneos.org when using the default GrapheneOS PSDS servers or
the standard time.xtracloud.net when using Qualcomm's servers. Stock
Pixel OS uses time.google.com but we follow Qualcomm's standard
settings to match other devices and to avoid the incompatible leap
second handling. These connections all go through the Owner VPN so it
isn't a real world fingerprinting issue.</p>
</li>
<li>
<p>Connectivity checks designed to mimic a web browser user agent are performed

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@ -672,9 +672,10 @@
<ul>
<li>Connectivity checks</li>
<li>Attestation key provisioning</li>
<li>GNSS almanac downloads (PSDS) on 6th generation Pixels</li>
<li>GNSS almanac downloads (PSDS) for Broadcom and Qualcomm (XTRA)</li>
<li>Secure User Plane Location (SUPL)</li>
<li>Network time</li>
<li>Vanadium (Chromium) component updates</li>
</ul>
<p>We provide a toggle to switch back to Google's servers for connectivity