Giving users more control over their location data

Posted by Jen Chai, Product Manager

Location data can deliver amazing, rich mobile experiences for users on Android such as finding a restaurant nearby, tracking the distance of a run, and getting turn-by-turn directions as you drive. Location is also one of the most sensitive types of personal information for a user. We want to give users simple, easy-to-understand controls for what data they are providing to apps, and yesterday, we announced in Android Q that we are giving users more control over location permissions. We are delighted by the innovative location experiences you provide to users through your apps, and we want to make this transition as straightforward for you as possible. This post dives deeper into the location permission changes in Q, what it may mean for your app, and how to get started with any updates needed.

Previously, a user had a single control to allow or deny an app access to device location, which covered location usage by the app both while it was in use and while it wasn't. Starting in Android Q, users have a new option to give an app access to location only when the app is being used; in other words, when the app is in the foreground. This means users will have a choice of three options for providing location to an app:

• "All the time" - this means an app can access location at any time
  
  
• "While in use" - this means an app can access location only while the app is being used
  
  
• "Deny" - this means an app cannot access location
  

Some apps or features within an app may only need location while the app is being used. For example, if a feature allows a user to search for a restaurant nearby, the app only needs to understand the user's location when the user opens the app to search for a restaurant.

However, some apps may need location even when the app is not in use. For example, an app that automatically tracks the mileage you drive for tax filing, without requiring you to interact with the app.

The new location control allows users to decide when device location data is provided to an app and prevents an app from getting location data that it may not need. Users will see this new option in the same permissions dialog that is presented today when an app requests access to location. This permission can also be changed at any time for any app from Settings-> Location-> App permission.

Here's how to get started

We know these updates may impact your apps. We respect our developer community, and our goal is to approach any change like this very carefully. We want to support you as much as we can by (1) releasing developer-impacting features in the first Q Beta to give you as much time as possible to make any updates needed in your apps and (2) providing detailed information in follow-up posts like this one as well as in the developer guides and privacy checklist. Please let us know if there are ways we can make the guides more helpful!

If your app has a feature requiring "all the time" permission, you'll need to add the new ACCESS_BACKGROUND_LOCATION permission to your manifest file when you target Android Q. If your app targets Android 9 (API level 28) or lower, the ACCESS_BACKGROUND_LOCATION permission will be automatically added for you by the system if you request either ACCESS_FINE_LOCATION or ACCESS_COARSE_LOCATION. A user can decide to provide or remove these location permissions at any time through Settings. To maintain a good user experience, design your app to gracefully handle when your app doesn't have background location permission or when it doesn't have any access to location.

Users will also be more likely to grant the location permission if they clearly understand why your app needs it. Consider asking for the location permission from users in context, when the user is turning on or interacting with a feature that requires it, such as when they are searching for something nearby. In addition, only ask for the level of access required for that feature. In other words, don't ask for "all the time" permission if the feature only requires "while in use" permission.

To learn more, read the developer guide on how to handle the new location controls.

Introducing Android Q Beta

Posted by Dave Burke, VP of Engineering

In 2019, mobile innovation is stronger than ever, with new technologies from 5G to edge to edge displays and even foldable screens. Android is right at the center of this innovation cycle, and thanks to the broad ecosystem of partners across billions of devices, Android's helping push the boundaries of hardware and software bringing new experiences and capabilities to users.

As the mobile ecosystem evolves, Android is focused on helping users take advantage of the latest innovations, while making sure users' security and privacy are always a top priority. Building on top of efforts like Google Play Protect and runtime permissions, Android Q brings a number of additional privacy and security features for users, as well as enhancements for foldables, new APIs for connectivity, new media codecs and camera capabilities, NNAPI extensions, Vulkan 1.1 support, faster app startup, and more.

Today we're releasing Beta 1 of Android Q for early adopters and a preview SDK for developers. You can get started with Beta 1 today by enrolling any Pixel device (including the original Pixel and Pixel XL, which we've extended support for by popular demand!) Please let us know what you think! Read on for a taste of what's in Android Q, and we'll see you at Google I/O in May when we'll have even more to share.

Building on top of privacy protections in Android

Android was designed with security and privacy at the center. As Android has matured, we've added a wide range of features to protect users, like file-based encryption, OS controls requiring apps to request permission before accessing sensitive resources, locking down camera/mic background access, lockdown mode, encrypted backups, Google Play Protect (which scans over 50 billion apps a day to identify potentially harmful apps and remove them), and much more. In Android Q, we've made even more enhancements to protect our users. Many of these enhancements are part of our work in Project Strobe.

Giving users more control over location

With Android Q, the OS helps users have more control over when apps can get location. As in prior versions of the OS, apps can only get location once the app has asked you for permission, and you have granted it.

One thing that's particularly sensitive is apps' access to location while the app is not in use (in the background). Android Q enables users to give apps permission to see their location never, only when the app is in use (running), or all the time (when in the background).

For example, an app asking for a user's location for food delivery makes sense and the user may want to grant it the ability to do that. But since the app may not need location outside of when it's currently in use, the user may not want to grant that access. Android Q now offers this greater level of control. Read the developer guide for details on how to adapt your app for this new control. Look for more user-centric improvements to come in upcoming Betas. At the same time, our goal is to be very sensitive to always give developers as much notice and support as possible with these changes.

More privacy protections in Android Q

Beyond changes to location, we're making further updates to ensure transparency, give users control, and secure personal data.

In Android Q, the OS gives users even more control over apps, controlling access to shared files. Users will be able to control apps' access to the Photos and Videos or the Audio collections via new runtime permissions. For Downloads, apps must use the system file picker, which allows the user to decide which Download files the app can access. For developers, there are changes to how your apps can use shared areas on external storage. Make sure to read the Scoped Storage changes for details.

We've also seen that users (and developers!) get upset when an app unexpectedly jumps into the foreground and takes over focus. To reduce these interruptions, Android Q will prevent apps from launching an Activity while in the background. If your app is in the background and needs to get the user's attention quickly -- such as for incoming calls or alarms -- you can use a high-priority notification and provide a full-screen intent. See the documentation for more information.

We're limiting access to non-resettable device identifiers, including device IMEI, serial number, and similar identifiers. Read the best practices to help you choose the right identifiers for your use case, and see the details here. We're also randomizing the device's MAC address when connected to different Wi-Fi networks by default -- a setting that was optional in Android 9 Pie.

We are bringing these changes to you early, so you can have as much time as possible to prepare. We've also worked hard to provide developers detailed information up front, we recommend reviewing the detailed docs on the privacy changes and getting started with testing right away.

New ways to engage users

In Android Q, we're enabling new ways to bring users into your apps and streamlining the experience as they transition from other apps.

Foldables and innovative new screens

Foldable devices have opened up some innovative experiences and use-cases. To help your apps to take advantage of these and other large-screen devices, we've made a number of improvements in Android Q, including changes to onResume and onPause to support multi-resume and notify your app when it has focus. We've also changed how the resizeableActivity manifest attribute works, to help you manage how your app is displayed on foldable and large screens. To you get started building and testing on these new devices, we've been hard at work updating the Android Emulator to support multiple-display type switching -- more details coming soon!

Sharing shortcuts

When a user wants to share content like a photo with someone in another app, the process should be fast. In Android Q we're making this quicker and easier with Sharing Shortcuts, which let users jump directly into another app to share content. Developers can publish share targets that launch a specific activity in their apps with content attached, and these are shown to users in the share UI. Because they're published in advance, the share UI can load instantly when launched.

The Sharing Shortcuts mechanism is similar to how App Shortcuts works, so we've expanded the ShortcutInfo API to make the integration of both features easier. This new API is also supported in the new ShareTarget AndroidX library. This allows apps to use the new functionality, while allowing pre-Q devices to work using Direct Share. You can find an early sample app with source code here.

Settings Panels

You can now also show key system settings directly in the context of your app, through a new Settings Panel API, which takes advantage of the Slices feature that we introduced in Android 9 Pie.

A settings panel is a floating UI that you invoke from your app to show system settings that users might need, such as internet connectivity, NFC, and audio volume. For example, a browser could display a panel with connectivity settings like Airplane Mode, Wi-Fi (including nearby networks), and Mobile Data. There's no need to leave the app; users can manage settings as needed from the panel. To display a settings panel, just fire an intent with one of the new Settings.Panel actions.

Connectivity

In Android Q, we've extended what your apps can do with Android's connectivity stack and added new connectivity APIs.

Connectivity permissions, privacy, and security

Most of our APIs for scanning networks already require COARSE location permission, but in Android Q, for Bluetooth, Cellular and Wi-Fi, we're increasing the protection around those APIs by requiring the FINE location permission instead. If your app only needs to make peer-to-peer connections or suggest networks, check out the improved Wi-Fi APIs below -- they simplify connections and do not require location permission.

In addition to the randomized MAC addresses that Android Q provides when connected to different Wi-Fi networks, we're adding new Wi-Fi standard support, WPA3 and Enhanced Open, to improve security for home and work networks as well as open/public networks.

Improved peer-to-peer and internet connectivity

In Android Q we refactored the Wi-Fi stack to improve privacy and performance, but also to improve common use-cases like managing IoT devices and suggesting internet connections -- without requiring the location permission.

The network connection APIs make it easier to manage IoT devices over local Wi-Fi, for peer-to-peer functions like configuring, downloading, or printing. Apps initiate connection requests indirectly by specifying preferred SSIDs & BSSIDs as WiFiNetworkSpecifiers. The platform handles the Wi-Fi scanning itself and displays matching networks in a Wi-Fi Picker. When the user chooses, the platform sets up the connection automatically.

The network suggestion APIs let apps surface preferred Wi-Fi networks to the user for internet connectivity. Apps initiate connections indirectly by providing a ranked list of networks and credentials as WifiNetworkSuggestions. The platform will seamlessly connect based on past performance when in range of those networks.

Wi-Fi performance mode

You can now request adaptive Wi-Fi in Android Q by enabling high performance and low latency modes. These will be of great benefit where low latency is important to the user experience, such as real-time gaming, active voice calls, and similar use-cases.

To use the new performance modes, call WifiManager.WifiLock.createWifiLock() with WIFI_MODE_FULL_LOW_LATENCY or WIFI_MODE_FULL_HIGH_PERF. In these modes, the platform works with the device firmware to meet the requirement with lowest power consumption.

Camera, media, graphics

Dynamic depth format for photos

Many cameras on mobile devices can simulate narrow depth of field by blurring the foreground or background relative to the subject. They capture depth metadata for various points in the image and apply a static blur to the image, after which they discard the depth metadata.

Starting in Android Q, apps can request a Dynamic Depth image which consists of a JPEG, XMP metadata related to depth related elements, and a depth and confidence map embedded in the same file on devices that advertise support.

Requesting a JPEG + Dynamic Depth image makes it possible for you to offer specialized blurs and bokeh options in your app. You can even use the data to create 3D images or support AR photography use-cases in the future. We're making Dynamic Depth an open format for the ecosystem, and we're working with our device-maker partners to make it available across devices running Android Q and later.

With Dynamic Depth image you can offer specialized blurs and bokeh options in your app.

New audio and video codecs

Android Q introduces support for the open source video codec AV1. This allows media providers to stream high quality video content to Android devices using less bandwidth. In addition, Android Q supports audio encoding using Opus - a codec optimized for speech and music streaming, and HDR10+ for high dynamic range video on devices that support it.

The MediaCodecInfo API introduces an easier way to determine the video rendering capabilities of an Android device. For any given codec, you can obtain a list of supported sizes and frame rates using VideoCodecCapabilities.getSupportedPerformancePoints(). This allows you to pick the best quality video content to render on any given device.

Native MIDI API

For apps that perform their audio processing in C++, Android Q introduces a native MIDI API to communicate with MIDI devices through the NDK. This API allows MIDI data to be retrieved inside an audio callback using a non-blocking read, enabling low latency processing of MIDI messages. Give it a try with the sample app and source code here.

ANGLE on Vulkan

To enable more consistency for game and graphics developers, we are working towards a standard, updateable OpenGL driver for all devices built on Vulkan. In Android Q we're adding experimental support for ANGLE on top of Vulkan on Android devices. ANGLE is a graphics abstraction layer designed for high-performance OpenGL compatibility across implementations. Through ANGLE, the many apps and games using OpenGL ES can take advantage of the performance and stability of Vulkan and benefit from a consistent, vendor-independent implementation of ES on Android devices. In Android Q, we're planning to support OpenGL ES 2.0, with ES 3.0 next on our roadmap.

We'll expand the implementation with more OpenGL functionality, bug fixes, and performance optimizations. See the docs for details on the current ANGLE support in Android, how to use it, and our plans moving forward. You can start testing with our initial support by opting-in through developer options in Settings. Give it a try today!

Vulkan everywhere

We're continuing to expand the impact of Vulkan on Android, our implementation of the low-overhead, cross-platform API for high-performance 3D graphics. Our goal is to make Vulkan on Android a broadly supported and consistent developer API for graphics. We're working together with our device manufacturer partners to make Vulkan 1.1 a requirement on all 64-bit devices running Android Q and higher, and a recommendation for all 32-bit devices. Going forward, this will help provide a uniform high-performance graphics API for apps and games to use.

Neural Networks API 1.2

Since introducing the Neural Networks API (NNAPI) in 2017, we've continued to expand the number of operations supported and improve existing functionality. In Android Q, we've added 60 new ops including ARGMAX, ARGMIN, quantized LSTM, alongside a range of performance optimisations. This lays the foundation for accelerating a much greater range of models -- such as those for object detection and image segmentation. We are working with hardware vendors and popular machine learning frameworks such as TensorFlow to optimize and roll out support for NNAPI 1.2.

Strengthening Android's Foundations

ART performance

Android Q introduces several new improvements to the ART runtime which help apps start faster and consume less memory, without requiring any work from developers.

Since Android Nougat, ART has offered Profile Guided Optimization (PGO), which speeds app startup over time by identifying and precompiling frequently executed parts of your code. To help with initial app startup, Google Play is now delivering cloud-based profiles along with APKs. These are anonymized, aggregate ART profiles that let ART pre-compile parts of your app even before it's run, giving a significant jump-start to the overall optimization process. Cloud-based profiles benefit all apps and they're already available to devices running Android P and higher.

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We're also continuing to make improvements in ART itself. For example, in Android Q we've optimized the Zygote process by starting your app's process earlier and moving it to a security container, so it's ready to launch immediately. We're storing more information in the app's heap image, such as classes, and using threading to load the image faster. We're also adding Generational Garbage Collection to ART's Concurrent Copying (CC) Garbage Collector. Generational CC is more efficient as it collects young-generation objects separately, incurring much lower cost as compared to full-heap GC, while still reclaiming a good amount of space. This makes garbage collection overall more efficient in terms of time and CPU, reducing jank and helping apps run better on lower-end devices.

Security for apps

BiometricPrompt is our unified authentication framework to support biometrics at a system level. In Android Q we're extending support for passive authentication methods such as face, and adding implicit and explicit authentication flows. In the explicit flow, the user must explicitly confirm the transaction in the TEE during the authentication. The implicit flow is designed for a lighter-weight alternative for transactions with passive authentication. We've also improved the fallback for device credentials when needed.

Android Q adds support for TLS 1.3, a major revision to the TLS standard that includes performance benefits and enhanced security. Our benchmarks indicate that secure connections can be established as much as 40% faster with TLS 1.3 compared to TLS 1.2. TLS 1.3 is enabled by default for all TLS connections. See the docs for details.

Compatibility through public APIs

Another thing we all care about is ensuring that apps run smoothly as the OS changes and evolves. Apps using non-SDK APIs risk crashes for users and emergency rollouts for developers. In Android Q we're continuing our long-term effort begun in Android P to move apps toward only using public APIs. We know that moving your app away from non-SDK APIs will take time, so we're giving you advance notice.

In Android Q we're restricting access to more non-SDK interfaces and asking you to use the public equivalents instead. To help you make the transition and prevent your apps from breaking, we're enabling the restrictions only when your app is targeting Android Q. We'll continue adding public alternative APIs based on your requests; in cases where there is no public API that meets your use case, please let us know.

It's important to test your apps for uses of non-SDK interfaces. We recommend using the StrictMode method detectNonSdkApiUsage() to warn when your app accesses non-SDK APIs via reflection or JNI. Even if the APIs are exempted (grey-listed) at this time, it's best to plan for the future and eliminate their use to reduce compatibility issues. For more details on the restrictions in Android Q, see the developer guide.

Modern Android

We're expanding our efforts to have all apps take full advantage of the security and performance features in the latest version of Android. Later this year, Google Play will require you to set your app's targetSdkVersion to 28 (Android 9 Pie) in new apps and updates. In line with these changes, Android Q will warn users with a dialog when they first run an app that targets a platform earlier than API level 23 (Android Marshmallow). Here's a checklist of resources to help you migrate your app.

We're also moving the ecosystem toward readiness for 64-bit devices. Later this year, Google Play will require 64-bit support in all apps. If your app uses native SDKs or libraries, keep in mind that you'll need to provide 64-bit compliant versions of those SDKs or libraries. See the developer guide for details on how to get ready.

Get started with Android Q Beta

With important privacy features that are likely to affect your apps, we recommend getting started with testing right away. In particular, you'll want to enable and test with Android Q storage changes, new location permission states, restrictions on background app launch, and restrictions on device identifiers. See the privacy documentation for details.

To get started, just install your current app from Google Play onto a device or Android Virtual Device running Android Q Beta and work through the user flows. The app should run and look great, and handle the Android Q behavior changes for all apps properly. If you find issues, we recommend fixing them in the current app, without changing your targeting level. Take a look at the migration guide for steps and a recommended timeline.

Next, update your app's targetSdkVersion to 'Q' as soon as possible. This lets you test your app with all of the privacy and security features in Android Q, as well as any other behavior changes for apps targeting Q.

Explore the new features and APIs

When you're ready, dive into Android Q and learn about the new features and APIs you can use in your apps. Take a look at the API diff report, the Android Q Beta API reference, and developer guides as a starting point. Also, on the Android Q Beta developer site, you'll find release notes and support resources for reporting issues.

To build with Android Q, download the Android Q Beta SDK and tools into Android Studio 3.3 or higher, and follow these instructions to configure your environment. If you want the latest fixes for Android Q related changes, we recommend you use Android Studio 3.5 or higher.

How do I get Android Q Beta?

It's easy - you can enroll here to get Android Q Beta updates over-the-air, on any Pixel device (and this year we're supporting all three generations of Pixel -- Pixel 3, Pixel 2, and even the original Pixel!). Downloadable system images for those devices are also available. If you don't have a Pixel device, you can use the Android Emulator, and download the latest emulator system images via the SDK Manager in Android Studio.

We plan to update the preview system images and SDK regularly throughout the preview. We'll have more features to share as the Beta program moves forward.

As always, your feedback is critical, so please let us know what you think — the sooner we hear from you, the more of your feedback we can integrate. When you find issues, please report them here. We have separate hotlists for filing platform issues, app compatibility issues, and third-party SDK issues.

Android Pie à la mode: Security & Privacy

Posted by Vikrant Nanda and René Mayrhofer, Android Security & Privacy Team

There is no better time to talk about Android dessert releases than the holidays because who doesn't love dessert? And what is one of our favorite desserts during the holiday season? Well, pie of course.

In all seriousness, pie is a great analogy because of how the various ingredients turn into multiple layers of goodness: right from the software crust on top to the hardware layer at the bottom. Read on for a summary of security and privacy features introduced in Android Pie this year.

Strengthening Android

Making Android more secure requires a combination of hardening the platform and advancing anti-exploitation techniques.

Platform hardening

With Android Pie, we updated File-Based Encryption to support external storage media (such as, expandable storage cards). We also introduced support for metadata encryption where hardware support is present. With filesystem metadata encryption, a single key present at boot time encrypts whatever content is not encrypted by file-based encryption (such as, directory layouts, file sizes, permissions, and creation/modification times).

Android Pie also introduced a BiometricPrompt API that apps can use to provide biometric authentication dialogs (such as, fingerprint prompt) on a device in a modality-agnostic fashion. This functionality creates a standardized look, feel, and placement for the dialog. This kind of standardization gives users more confidence that they're authenticating against a trusted biometric credential checker.

New protections and test cases for the Application Sandbox help ensure all non-privileged apps targeting Android Pie (and all future releases of Android) run in stronger SELinux sandboxes. By providing per-app cryptographic authentication to the sandbox, this protection improves app separation, prevents overriding safe defaults, and (most significantly) prevents apps from making their data widely accessible.

Anti-exploitation improvements

With Android Pie, we expanded our compiler-based security mitigations, which instrument runtime operations to fail safely when undefined behavior occurs.

Control Flow Integrity (CFI) is a security mechanism that disallows changes to the original control flow graph of compiled code. In Android Pie, it has been enabled by default within the media frameworks and other security-critical components, such as for Near Field Communication (NFC) and Bluetooth protocols. We also implemented support for CFI in the Android common kernel, continuing our efforts to harden the kernel in previous Android releases.

Integer Overflow Sanitization is a security technique used to mitigate memory corruption and information disclosure vulnerabilities caused by integer operations. We've expanded our use of Integer Overflow sanitizers by enabling their use in libraries where complex untrusted input is processed or where security vulnerabilities have been reported.

Continued investment in hardware-backed security

One of the highlights of Android Pie is Android Protected Confirmation, the first major mobile OS API that leverages a hardware-protected user interface (Trusted UI) to perform critical transactions completely outside the main mobile operating system. Developers can use this API to display a trusted UI prompt to the user, requesting approval via a physical protected input (such as, a button on the device). The resulting cryptographically signed statement allows the relying party to reaffirm that the user would like to complete a sensitive transaction through their app.

We also introduced support for a new Keystore type that provides stronger protection for private keys by leveraging tamper-resistant hardware with dedicated CPU, RAM, and flash memory. StrongBox Keymaster is an implementation of the Keymaster hardware abstraction layer (HAL) that resides in a hardware security module. This module is designed and required to have its own processor, secure storage, True Random Number Generator (TRNG), side-channel resistance, and tamper-resistant packaging.

Other Keystore features (as part of Keymaster 4) include Keyguard-bound keys, Secure Key Import, 3DES support, and version binding. Keyguard-bound keys enable use restriction so as to protect sensitive information. Secure Key Import facilitates secure key use while protecting key material from the application or operating system. You can read more about these features in our recent blog post as well as the accompanying release notes.

Enhancing user privacy

User privacy has been boosted with several behavior changes, such as limiting the access background apps have to the camera, microphone, and device sensors. New permission rules and permission groups have been created for phone calls, phone state, and Wi-Fi scans, as well as restrictions around information retrieved from Wi-Fi scans. We have also added associated MAC address randomization, so that a device can use a different network address when connecting to a Wi-Fi network.

On top of that, Android Pie added support for encrypting Android backups with the user's screen lock secret (that is, PIN, pattern, or password). By design, this means that an attacker would not be able to access a user's backed-up application data without specifically knowing their passcode. Auto backup for apps has been enhanced by providing developers a way to specify conditions under which their app's data is excluded from auto backup. For example, Android Pie introduces a new flag to determine whether a user's backup is client-side encrypted.

As part of a larger effort to move all web traffic away from cleartext (unencrypted HTTP) and towards being secured with TLS (HTTPS), we changed the defaults for Network Security Configuration to block all cleartext traffic. We're protecting users with TLS by default, unless you explicitly opt-in to cleartext for specific domains. Android Pie also adds built-in support for DNS over TLS, automatically upgrading DNS queries to TLS if a network's DNS server supports it. This protects information about IP addresses visited from being sniffed or intercepted on the network level.

We believe that the features described in this post advance the security and privacy posture of Android, but you don't have to take our word for it. Year after year our continued efforts are demonstrably resulting in better protection as evidenced by increasing exploit difficulty and independent mobile security ratings. Now go and enjoy some actual pie while we get back to preparing the next Android dessert release!

Acknowledgements: This post leveraged contributions from Chad Brubaker, Janis Danisevskis, Giles Hogben, Troy Kensinger, Ivan Lozano, Vishwath Mohan, Frank Salim, Sami Tolvanen, Lilian Young, and Shawn Willden.

Double Stuffed Security in Android Oreo

Posted by Gian G Spicuzza, Android Security team

Android Oreo is stuffed full of security enhancements. Over the past few months,
we've covered how we've improved the security of the Android platform and its
applications: from href="https://android-developers.googleblog.com/2017/08/making-it-safer-to-get-apps-on-android-o.html">making
it safer to get apps, dropping href="https://android-developers.googleblog.com/2017/04/android-o-to-drop-insecure-tls-version.html">insecure
network protocols, providing more href="https://android-developers.googleblog.com/2017/04/changes-to-device-identifiers-in.html">user
control over identifiers, href="https://android-developers.googleblog.com/2017/08/hardening-kernel-in-android-oreo.html">hardening
the kernel, href="https://android-developers.googleblog.com/2017/07/shut-hal-up.html">making
Android easier to update, all the way to href="https://android-developers.googleblog.com/2017/06/2017-android-security-rewards.html">doubling
the Android Security Rewards payouts. Now that Oreo is out the door, let's
take a look at all the goodness inside.

Expanding support for hardware security

Android already supports href="https://source.android.com/security/verifiedboot/">Verified Boot,
which is designed to prevent devices from booting up with software that has been
tampered with. In Android Oreo, we added a reference implementation for Verified
Boot running with href="https://source.android.com/devices/architecture/treble">Project
Treble, called Android Verified Boot 2.0 (AVB). AVB has a couple of cool
features to make updates easier and more secure, such as a common footer format
and rollback protection. Rollback protection is designed to prevent a device to
boot if downgraded to an older OS version, which could be vulnerable to an
exploit. To do this, the devices save the OS version using either special
hardware or by having the Trusted Execution Environment (TEE) sign the data.
Pixel 2 and Pixel 2 XL come with this protection and we recommend all device
manufacturers add this feature to their new devices.

Oreo also includes the new href="https://android-review.googlesource.com/#/c/platform/hardware/interfaces/+/527086/-1..1/oemlock/1.0/IOemLock.hal">OEM
Lock Hardware Abstraction Layer (HAL) that gives device manufacturers more
flexibility for how they protect whether a device is locked, unlocked, or
unlockable. For example, the new Pixel phones use this HAL to pass commands to
the bootloader. The bootloader analyzes these commands the next time the device
boots and determines if changes to the locks, which are securely stored in
Replay Protected Memory Block (RPMB), should happen. If your device is stolen,
these safeguards are designed to prevent your device from being reset and to
keep your data secure. This new HAL even supports moving the lock state to
dedicated hardware.

Speaking of hardware, we've invested support in tamper-resistant hardware, such
as the href="https://android-developers.googleblog.com/2017/11/how-pixel-2s-security-module-delivers.html">security
module found in every Pixel 2 and Pixel 2 XL. This physical chip prevents
many software and hardware attacks and is also resistant to physical penetration
attacks. The security module prevents deriving the encryption key without the
device's passcode and limits the rate of unlock attempts, which makes many
attacks infeasible due to time restrictions.

While the new Pixel devices have the special security module, all new href="https://www.android.com/gms/">GMS devices shipping with Android Oreo
are required to implement href="https://android-developers.googleblog.com/2017/09/keystore-key-attestation.html">key
attestation. This provides a mechanism for strongly href="https://source.android.com/security/keystore/attestation#id-attestation">attesting
IDs such as hardware identifiers.

We added new features for enterprise-managed devices as well. In work profiles,
encryption keys are now ejected from RAM when the profile is off or when your
company's admin remotely locks the profile. This helps secure enterprise data at
rest.

Platform hardening and process isolation

As part of href="https://android-developers.googleblog.com/2017/05/here-comes-treble-modular-base-for.html">Project
Treble, the Android framework was re-architected to make updates easier and
less costly for device manufacturers. This separation of platform and
vendor-code was also designed to improve security. Following the href="https://en.wikipedia.org/wiki/Principle_of_least_privilege">principle of
least privilege, these HALs run in their href="https://android-developers.googleblog.com/2017/07/shut-hal-up.html">own
sandbox and only have access to the drivers and permissions that are
absolutely necessary.

Continuing with the href="https://android-developers.googleblog.com/2016/05/hardening-media-stack.html">media
stack hardening in Android Nougat, most direct hardware access has been
removed from the media frameworks in Oreo resulting in better isolation.
Furthermore, we've enabled Control Flow Integrity (CFI) across all media
components. Most vulnerabilities today are exploited by subverting the normal
control flow of an application, instead changing them to perform arbitrary
malicious activities with all the privileges of the exploited application. CFI
is a robust security mechanism that disallows arbitrary changes to the original
control flow graph of a compiled binary, making it significantly harder to
perform such attacks.

In addition to these architecture changes and CFI, Android Oreo comes with a
feast of other tasty platform security enhancements:

• href="https://android-developers.googleblog.com/2017/07/seccomp-filter-in-android-o.html">Seccomp
  filtering: makes some unused syscalls unavailable to apps so that
  they can't be exploited by potentially harmful apps.
  
• Hardened
  usercopy: A recent href="https://events.linuxfoundation.org/sites/events/files/slides/Android-%20protecting%20the%20kernel.pdf">survey
  of security bugs on Android
  revealed that invalid or missing bounds checking was seen in approximately 45%
  of kernel vulnerabilities. We've backported a bounds checking feature to Android
  kernels 3.18 and above, which makes exploitation harder while also helping
  developers spot issues and fix bugs in their code.
  
• Privileged Access Never (PAN) emulation: Also backported to
  3.18 kernels and above, this feature prohibits the kernel from accessing user
  space directly and ensures developers utilize the hardened functions to access
  user space.
  
• Kernel Address Space Layout Randomization (KASLR):
  Although Android has supported userspace Address Space Layout Randomization
  (ASLR) for years, we've backported KASLR to help mitigate vulnerabilities on
  Android kernels 4.4 and newer. KASLR works by randomizing the location where
  kernel code is loaded on each boot, making code reuse attacks probabilistic and
  therefore more difficult to carry out, especially remotely.

App security and device identifier changes

Android
Instant Apps run in a restricted sandbox which limits permissions and
capabilities such as reading the on-device app list or transmitting cleartext
traffic. Although introduced during the Android Oreo release, Instant Apps
supports devices running href="https://www.android.com/versions/lollipop-5-0/">Android Lollipop and
later.

In order to handle untrusted content more safely, we've href="https://android-developers.googleblog.com/2017/06/whats-new-in-webview-security.html">isolated
WebView by splitting the rendering engine into a separate process and
running it within an isolated sandbox that restricts its resources. WebView also
supports Safe Browsing to protect
against potentially dangerous sites.

Lastly, we've made href="https://android-developers.googleblog.com/2017/04/changes-to-device-identifiers-in.html">significant
changes to device identifiers to give users more control, including:

• Moving the static Android ID and Widevine values to an
  app-specific value, which helps limit the use of device-scoped non-resettable
  IDs.
  
• In accordance with href="https://tools.ietf.org/html/rfc7844#section-3.7">IETF RFC 7844
  anonymity profile, net.hostname is now empty and the DHCP client no
  longer sends a hostname.
  
• For apps that require a device ID, we've built a Build.getSerial()
API and protected it behind a permission.
  
• Alongside security researchers¹, we designed a robust MAC address
  randomization for Wi-Fi scan traffic in various chipsets firmware.

Android Oreo brings in all of these improvements, and href="https://www.android.com/versions/oreo-8-0/">many more. As always, we
appreciate feedback and welcome suggestions for how we can improve Android.
Contact us at security@android.com.

_____________________________________________________________________

1: Glenn Wilkinson and team at Sensepost, UK, Célestin Matte, Mathieu Cunche:
University of Lyon, INSA-Lyon, CITI Lab, Inria Privatics, Mathy Vanhoef, KU
Leuven