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Preparation

tar -xvzf PScout.tar.gz in <PScout_DIR> source bin/setup_env

Install XML::Simple (if not installed already) sudo perl -MCPAN -e shell install XML::Simple

PScout directory contents: <PScout_DIR>/bin - various scripts used in the analysis <PScout_DIR>/soot - soot analysis programs of java class files

<PScout_DIR>/results

  • <android_version>_allmappings: API calls (both documented and undocumented) to permission mapping
  • <android_version>_publishedapimapping: documented API calls to permission mapping
  • <android_version>_intentpermissions: intents with permission
  • <android_version>_contentproviderpermission: content provider (URI string "content://") with permission
  • <android_version>_contentproviderfieldpermission: content provider (URI field) with permission

How to Run PScout:

mkdir <ANDROID_CLASS_DIR> # create new directory under <PScout_DIR> cd <ANDROID_CLASS_DIR> ../bin/setupanalysis.sh <ANDROID_DIR> # <ANDROID_DIR> is the root directory of the Android source code (should be already complied with lunch full-eng) # performs steps 1-3 described in the following "Detailed Analysis Steps Section" testsetup # step 4 (a few seconds) ../bin/dumpclass.sh # step 5 (~half a day) ../bin/postprocess_1.sh # steps 6-11 (a few minutes) ../bin/intentpermissioncheck.sh # step 12 (~half a day) ../bin/postprocess_2.sh # step 12-16 (a few minutes)

Detailed Analysis Step Descriptions

1: Get the relevant class files from the android build <ANDROID_DIR> root directory

Put all classes in a new directory <ANDROID_CLASS_DIR> under <PScout_DIR> ../bin/getclasses.pl <ANDROID_DIR> ../bin/extractjar.sh rm -f *.jar

Create a list of class name ../bin/createclasslist.sh under <ANDROID_CLASS_DIR>

2: Parse all AndroidManifest.xml files (in ANDROID_DIR) for permission information

Under <ANDROID_DIR> run the following: find -name AndroidManifest.xml > manifestlist <PScout_DIR>/bin/parseandroidmanifest.pl > manifestpermission

grep ^contents:// manifestpermission | grep -v grantUriPermissions | sort -u > contentproviderpermission sed -i 's/^contents/content/' contentproviderpermission mv contentproviderpermission <ANDROID_CLASS_DIR>

grep ^PROVIDER: manifestpermission | sort -u > providerauth mv providerauth <ANDROID_CLASS_DIR>

grep ^Intent: manifestpermission | sort -u > intentpermission sed -i 's/^Intent://' intentpermission mv intentpermission <ANDROID_CLASS_DIR>

Note: At this point, unless otherwise specified, all commands in future steps should be executed under <ANDROID_CLASS_DIR>

3: Generate list of permissions to be analyzed by PScout

Create list of permissions available to 3rd party applications ../bin/parsepermission.pl <ANDROID_DIR>/frameworks/base/core/res/AndroidManifest.xml > permissions

Output files:

  • permissions

4: Testing setup

runsoot dump.DumpClass com.android.internal.telephony.gsm.GSMPhone under <ANDROID_CLASS_DIR>

If you see Exception in thread "main" java.lang.RuntimeException: couldn't find class: com.android.internal.telephony.gsm.GSMPhone$1 (is your soot-class-path set properly?) do the following: ../bin/compileemptyclass.pl com.android.internal.telephony.gsm.GSMPhone$1

If setting is correct, there should be no errors.

5: SOOT dump class information (this step should take ~day to finish)

../bin/dumpclass.sh

Output files:i

  • classhierarchy
  • rawcallgraph
  • permissionstringusage
  • message
  • handlemessageswitch
  • rpcmethod
  • clearrestoreuid
  • urifield

Note:

  • modify the classlist file to change the list of class files to be processed (useful if computer died(?) in the middle of an analysis)
  • the file 'processed' stores the list of classes examined so far
  • run 'wc processed' to get an idea on the progress (# of lines = # classes processed)

6: Build basic call graph

../bin/buildcallgraph.pl | sort -u > callgraph

Output files:

  • callgraph

7: Create message sending edges ../bin/analyzemessages.pl > sendmessagecallgraphedges

Output files

  • sendmessagecallgraphedges

8: AIDL RPC ../bin/createrpcedge.pl > aidlcallgraphedges ../bin/removerpcedge.pl > callgraphnorpc

9: String permission checks ../bin/analyzepermissionusage.pl > pchk ../bin/formatpermissioncheck.pl

Output files:

  • stringpermissioncheck
  • sendreceivepermissioncheck

10: Uri permission checks ../bin/analyzeurifield.pl > contentprovidercheck

Outputfiles:

  • contentprovidercheck
  • contentproviderfieldpermission

11: SOOT Intents with "dynamic" send/receive permission ../bin/intentwithpermission.sh ../bin/analyzeintent.pl > intentwithdynamicpermission cat intentpermission intentwithdynamicpermission > intentpermissions

Outputfiles:

  • intentwithdynamicpermission
  • intentpermissions

12: SOOT Intent permission check (~day) ../bin/intentpermissioncheck.sh ../bin/analyzeintentcheck.pl > intentpermissioncheck

Outputfiles:

  • intentpermissioncheck

13: API mapping

cp <ANDROID_DIR>/frameworks/base/api/current.xml <ANDROID_CLASS_DIR> Note: when analyzing android 4.0, copy current.txt instead

../bin/broadcaststickycheck.pl > broadcaststickycheck ../bin/apimapping.pl > API

Output files:

  • permissionreachedprovider

14: New content permission requirement found from first apimapping.pl pass

../bin/analyzereachedprovider.pl > reachedcontentproviderpermission ../bin/analyzeurifield.pl > contentproviderdynamiccheck

15: Second (final) API mapping

../bin/apimapping.pl > API grep -e ^Permission -e Callers: -e ^< API > allmappings

Output files:

  • allmappings
  • publishedapimapping

16: Generate some basic stats

../bin/generatestats.pl > stats

Output files:

  • stats