Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Android Security Features
Search
Dave Smith
November 09, 2016
Programming
4
700
Android Security Features
Overview of the core platform elements that make up the Android security model for applications.
Dave Smith
November 09, 2016
Tweet
Share
More Decks by Dave Smith
See All by Dave Smith
ConstraintLayout, Inside and Out
devunwired
21
1.7k
Digging Into Android System Services
devunwired
8
1.6k
Flattening Layouts with Constraints
devunwired
3
290
Hello, Brillo: ELC Edition
devunwired
0
260
Mastering CoordinatorLayout Behaviors
devunwired
16
1.4k
Hello, Brillo
devunwired
1
2.1k
Google Proximity Beacons Overview
devunwired
4
240
Proximity Beacons and the Nearby API
devunwired
1
1.9k
Getting Your Act Together with CoordinatorLayout
devunwired
7
480
Other Decks in Programming
See All in Programming
Goで実践するドメイン駆動開発 AIと歩み始めた新規プロダクト開発の現在地
imkaoru
4
640
私達はmodernize packageに夢を見るか feat. go/analysis, go/ast / Go Conference 2025
kaorumuta
2
490
CSC509 Lecture 01
javiergs
PRO
1
430
Advance Your Career with Open Source
ivargrimstad
0
340
ABEMAモバイルアプリが Kotlin Multiplatformと歩んだ5年 ─ 導入と運用、成功と課題 / iOSDC 2025
akkyie
0
330
階層構造を表現するデータ構造とリファクタリング 〜1年で10倍成長したプロダクトの変化と課題〜
yuhisatoxxx
3
920
CSC305 Lecture 02
javiergs
PRO
1
260
After go func(): Goroutines Through a Beginner’s Eye
97vaibhav
0
230
Go言語の特性を活かした公式MCP SDKの設計
hond0413
1
180
Playwrightはどのようにクロスブラウザをサポートしているのか
yotahada3
7
2.3k
育てるアーキテクチャ:戦い抜くPythonマイクロサービスの設計と進化戦略
fujidomoe
1
150
ИИ-Агенты в каждый дом – Алексей Порядин, PythoNN
sobolevn
0
150
Featured
See All Featured
"I'm Feeling Lucky" - Building Great Search Experiences for Today's Users (#IAC19)
danielanewman
229
22k
The Cost Of JavaScript in 2023
addyosmani
53
9k
How to Ace a Technical Interview
jacobian
280
24k
Rails Girls Zürich Keynote
gr2m
95
14k
Testing 201, or: Great Expectations
jmmastey
45
7.7k
Measuring & Analyzing Core Web Vitals
bluesmoon
9
610
GitHub's CSS Performance
jonrohan
1032
460k
Building Better People: How to give real-time feedback that sticks.
wjessup
368
20k
Typedesign – Prime Four
hannesfritz
42
2.8k
XXLCSS - How to scale CSS and keep your sanity
sugarenia
248
1.3M
Code Review Best Practice
trishagee
72
19k
What's in a price? How to price your products and services
michaelherold
246
12k
Transcript
Android Security Features Dave Smith, PE @devunwired
App Code Sandbox Encryption Permissions
App Code
App Manifest Compiled Code Resources Signature Info Application Package (APK)
App Manifest Compiled Code Resources Signature Info Application Package (APK)
Authenticate Developer Identity Prevent APK Tampering
JAR Signer Hash Files Hash Hashes Sign w/ Private Key
APK Signature
JAR Signer APK Signature Hash Files Hash Hashes Sign w/
Private Key Hash 1MB Chunks Sign w/ Private Key Hash Hashes
Sandbox
Application Sandbox Process Isolation Unique App UID SELinux Domains
# ps USER PID PPID ... NAME ... system 1723
1240 ... com.android.settings u0_a10 1803 1240 ... android.ext.services u0_a32 1824 1240 ... com.android.deskclock u0_a1 1896 1240 ... android.process.acore u0_a55 1914 1240 ... com.android.printspooler u0_a13 1942 1240 ... com.android.launcher3 system 1974 1240 ... com.android.keychain u0_a8 2000 1240 ... android.process.media u0_a26 2064 1240 ... com.android.calendar u0_a66 2096 1240 ... com.android.quicksearchbox u0_a67 2123 1240 ... com.android.messaging u0_a6 2189 1240 ... com.android.dialer u0_a35 2209 1240 ... com.android.email u0_a65 2229 1240 ... com.android.gallery3d
# ps USER PID PPID ... NAME ... system 1723
1240 ... com.android.settings u0_a10 1803 1240 ... android.ext.services u0_a32 1824 1240 ... com.android.deskclock u0_a1 1896 1240 ... android.process.acore u0_a55 1914 1240 ... com.android.printspooler u0_a13 1942 1240 ... com.android.launcher3 system 1974 1240 ... com.android.keychain u0_a8 2000 1240 ... android.process.media u0_a26 2064 1240 ... com.android.calendar u0_a66 2096 1240 ... com.android.quicksearchbox u0_a67 2123 1240 ... com.android.messaging u0_a6 2189 1240 ... com.android.dialer u0_a35 2209 1240 ... com.android.email u0_a65 2229 1240 ... com.android.gallery3d
# cd /data/data/com.android.launcher3 # ls -l total 24 drwxrwx--x 2
u0_a13 u0_a13 4096 2016-09-15 22:23 cache drwxrwx--x 2 u0_a13 u0_a13 4096 2016-09-15 22:23 databases drwxrwx--x 2 u0_a13 u0_a13 4096 2016-11-01 22:13 shared_prefs # cd /data/data/ # ls -l ... drwxr-x--x 6 u0_a6 u0_a6 4096 2016-09-15 22:23 com.android.dialer drwxr-x--x 6 u0_a35 u0_a35 4096 2016-09-15 22:23 com.android.email drwxr-x--x 5 u0_a13 u0_a13 4096 2016-09-15 22:23 com.android.launcher3
$ ps -Z LABEL USER ... NAME ... u:r:system_app:s0 system
... com.android.settings u:r:platform_app:s0:c512,c768 u0_a10 ... android.ext.services u:r:untrusted_app:s0:c512,c768 u0_a32 ... com.android.deskclock u:r:priv_app:s0:c512,c768 u0_a1 ... android.process.acore u:r:untrusted_app:s0:c512,c768 u0_a55 ... com.android.printspooler u:r:priv_app:s0:c512,c768 u0_a13 ... com.android.launcher3 u:r:system_app:s0 system ... com.android.keychain u:r:priv_app:s0:c512,c768 u0_a8 ... android.process.media u:r:untrusted_app:s0:c512,c768 u0_a26 ... com.android.calendar u:r:untrusted_app:s0:c512,c768 u0_a66 ... com.android.quicksearchbox u:r:platform_app:s0:c512,c768 u0_a67 ... com.android.messaging u:r:priv_app:s0:c512,c768 u0_a6 ... com.android.dialer u:r:untrusted_app:s0:c512,c768 u0_a35 ... com.android.email u:r:untrusted_app:s0:c512,c768 u0_a65 ... com.android.gallery3d
Data Encryption + Verified Boot
Disk Encryption Encrypts All Writable Data No Passcode Required /data
dm-crypt Android
Verified Boot Halt Boot on Error Protect Runtime Reads /system
dm-verity Android Hash System Blocks
Permissions
<manifest package="com.android.browser"> … <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> …
</manifest>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="android"> ... <permission android:name="android.permission.INTERNET" android:description="@string/permdesc_createNetworkSockets" android:label="@string/permlab_createNetworkSockets" android:protectionLevel="normal"
/> ... <permission android:name="android.permission.ACCESS_FINE_LOCATION" android:permissionGroup="android.permission-group.LOCATION" android:label="@string/permlab_accessFineLocation" android:description="@string/permdesc_accessFineLocation" android:protectionLevel="dangerous" /> ... </manifest> frameworks/base/core/res/AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="android"> ... <permission android:name="android.permission.INTERNET" android:description="@string/permdesc_createNetworkSockets" android:label="@string/permlab_createNetworkSockets" android:protectionLevel="normal"
/> ... <permission android:name="android.permission.ACCESS_FINE_LOCATION" android:permissionGroup="android.permission-group.LOCATION" android:label="@string/permlab_accessFineLocation" android:description="@string/permdesc_accessFineLocation" android:protectionLevel="dangerous" /> ... </manifest> frameworks/base/core/res/AndroidManifest.xml
Permissions Enforcement Kernel Groups Binder IPC
<permissions> … <permission name="android.permission.INTERNET" > <group gid="inet" /> </permission> …
</permissions> … #define AID_INET 3003 /* can create AF_INET and AF_INET6 sockets */ … static const struct android_id_info android_ids[] = { … { "inet", AID_INET, }, … }; … frameworks/base/data/etc/platform.xml system/core/include/private/android_filesystem_config.h
# ps | grep browser u0_a17 2276 1212 ... com.android.browser
# cat /proc/2276/status Name: android.browser State: S (sleeping) Tgid: 2276 Pid: 2276 PPid: 1212 TracerPid: 0 Uid: 10017 10017 10017 10017 Gid: 10017 10017 10017 10017 FDSize: 256 Groups: 3003 9997 50017 ...
Application System Server Manager Service Binder IPC
Application System Server Manager Service Binder IPC Binder.getCallingUid() Binder.getCallingPid()
Vibrator vib = (Vibrator) getSystemService(VIBRATOR_SERVICE); vib.vibrate(500); public class VibratorService extends
IVibratorService.Stub { … public void vibrate(int uid, String packageName, long milliseconds, IBinder token) { if (mContext.checkCallingOrSelfPermission(android.Manifest.permission.VIBRATE) != PackageManager.PERMISSION_GRANTED) { throw new SecurityException("Requires VIBRATE permission"); } … } … }
public class VibratorService extends IVibratorService.Stub { … public void vibrate(int
uid, String packageName, long milliseconds, IBinder token) { if (mContext.checkCallingOrSelfPermission(android.Manifest.permission.VIBRATE) != PackageManager.PERMISSION_GRANTED) { throw new SecurityException("Requires VIBRATE permission"); } … } … } Vibrator vib = (Vibrator) getSystemService(VIBRATOR_SERVICE); vib.vibrate(500);
Protect code integrity Prohibit unauthorized access Preserve data integrity Provide
user control
@devunwired +DaveSmithDev milehighandroid.com wiresareobsolete.com