Datasets:
Devilishcode
/
hacking

Dataset card Data Studio Files
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text
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1.99k
/data/app/~~ICLdeF7FOXIe1b9MxToZGQ==/app.organicmaps-2xFay0QEb95pHRC_k_T1gA=
=/oat/arm64/base.odex
```
---[ 3.2 - How Can We Compile an App's Code Fully Ahead-of-Time?
We could run dex2oat ourselves, recreating the invocation as closely as
possible. Fortunately we don't have to deal with this, and can instead ask
Android nicely to do it for us. The package manager `pm` will do it:
```console
$ adb shell pm compile -m everything app.organicmaps
Success
```
Looking at the logs, we see a very similar invocation, but now the compiler
filter has been set to 'everything':
```console
$ adb logcat artd:I *:S # formatted for convenience
[...]
02-29 15:51:15.515 6074 6583 I artd : Running dex2oat:
/apex/com.android.art/bin/art_exec --drop-capabilities
--set-task-profile=Dex2OatBootComplete --set-priority=background
--keep-fds=6:7:8:9:10:11:12 --
/apex/com.android.art/bin/dex2oat64
--zip-fd=6 -zip-location=/data/app/[...]/base.apk
--oat-fd=7 --oat-location=/data/app/[...]/oat/arm64/base.odex
--output-vdex-fd=8 --swap-fd=9 --class-loader-context-fds=10:11
--class-loader-context=PCL[]{PCL[...]}
--classpath-dir=/data/app/[...] --input-vdex-fd=12
--instruction-set=arm64 --instruction-set-features=default
--instruction-set-variant=cortex-a55
--compiler-filter=everything
--compilation-reason=cmdline --compact-dex-level=none
--max-image-block-size=524288 --resolve-startup-const-strings=true
--generate-mini-debug-info --runtime-arg -Xtarget-sdk-version:35
--runtime-arg -Xhidden-api-policy:enabled --cpu-set=0,1,2,3,4,5,6,7,8
-j8 --runtime-arg -Xms64m --runtime-arg -Xmx512m
--comments=app-name:app.organicmaps,[...]
```
And indeed, the odex now contains a lot more binary code:
```console
$ adb shell ls -lah
/data/app/~~ICLdeF7FOXIe1b9MxToZGQ==/app.organicmaps-2xFay0QEb95pHRC_k_T1gA=
=/oat/arm64/base.odex
-rw-r--r-- 1 system all_a306 14M 2025-02-29 15:51
/data/app/~~ICLdeF7FOXIe1b9MxToZGQ==/app.organicmaps-2xFay0QEb95pHRC_k_T1gA=
=/oat/arm64/base.odex
```
Pull the file from your (virtual) device and you are ready to go! We'll
save our example as `app.organicmaps.odex`.
---[ 3.3 - How Can We Disassemble OAT Files?
It's an ELF! Throw it in your favorite disassembler. They all do reasonably
well, we checked by looking at the function boundaries [12]!
```console
$ file app.organicmaps.odex
oats/PXL8_everything/app.organicmaps.odex: ELF 64-bit LSB shared object,
ARM aarch64, version 1 (GNU/Linux), dynamically linked, stripped
```
We use Ghidra 11.0.3 because it supports the BinExport [13] plugin and is
freely available. We provide a script to do this headlessly, but using the
GUI works just as well.
```console
$ ./ghidra_export_binexport.sh app.organicmaps.odex
app.organicmaps.odex.BinExport
[...]
Total Time 75 secs
[...]
```
Not bad, let's try this with a more complex app like Signal [14]:
```console
$ ./ghidra_export_binexport.sh org.thoughtcrime.securesms.odex
org.thoughtcrime.securesms.odex.BinExport
[...]
Total Time 2642 secs
[...]
```
Well, this is hardly ideal. Taking almost an hour to prepare an app will
not scale, even though we need to disassemble each OAT file we want to
compare only once. In the script we already included some speedups, like
disabling the GCCExceptionAnalyzer, which takes time but in our case is
pointless, since the OAT file has never seen GCC. But modern apps are
ridiculously big. The Signal app has around 500k Dalvik methods alone, not
counting native libraries. Its Linux app has around 40k, including all
dynamically loaded libraries such as glibc. No wonder it takes almost an
hour to analyze the OAT.
Fortunately, Android provides another way to see the disassembly with the