• Telling mounted filesystems to freeze. They can quiesce any kthreads they created.
• Device drivers quiescing any kthreads they created, from their PM suspend implementation.

buildscript  
    dependencies  
        classpath 'com.android.tools.build:gradle:2.2.+'
        classpath 'com.android.tools.build:transform-api:1.5.+'
        classpath 'org.javassist:javassist:3.21.+'
        classpath 'commons-io:commons-io:2.4'
     
 

Context This section adds some context to the example. Feel free to skip it. Dashkiosk is an application to manage dashboards on many displays. It provides an Android application you can install on one of those cheap Android sticks. Under the table, the application is an embedded webview backed by the Crosswalk Project web runtime which brings an up-to-date web engine, even for older versions of Android¹. Recently, a security vulnerability has been spotted in how invalid certificates were handled. When a certificate cannot be verified, the webview defers the decision to the host application by calling the onReceivedSslError() method:

Notify the host application that an SSL error occurred while loading a resource. The host application must call either callback.onReceiveValue(true) or callback.onReceiveValue(false). Note that the decision may be retained for use in response to future SSL errors. The default behavior is to pop up a dialog.

The default behavior is specific to Crosswalk webview: the Android builtin one just cancels the load. Unfortunately, the fix applied by Crosswalk is different and, as a side effect, the onReceivedSslError() method is not invoked anymore². Dashkiosk comes with an option to ignore TLS errors³. The mentioned security fix breaks this feature. The following example will demonstrate how to patch Crosswalk to recover the previous behavior⁴.

Simple method replacement Let s replace the shouldDenyRequest() method from the org.xwalk.core.internal.SslUtil class with this version:

// In SslUtil class
public static boolean shouldDenyRequest(int error)  
    return false;
 

Transform registration Gradle Transform API enables the manipulation of compiled class files before they are converted to DEX files. To declare a transform and register it, include the following code in your build.gradle:

import com.android.build.api.transform.Context
import com.android.build.api.transform.QualifiedContent
import com.android.build.api.transform.Transform
import com.android.build.api.transform.TransformException
import com.android.build.api.transform.TransformInput
import com.android.build.api.transform.TransformOutputProvider
import org.gradle.api.logging.Logger
class PatchXWalkTransform extends Transform  
    Logger logger = null;
    public PatchXWalkTransform(Logger logger)  
        this.logger = logger
     
    @Override
    String getName()  
        return "PatchXWalk"
     
    @Override
    Set<QualifiedContent.ContentType> getInputTypes()  
        return Collections.singleton(QualifiedContent.DefaultContentType.CLASSES)
     
    @Override
    Set<QualifiedContent.Scope> getScopes()  
        return Collections.singleton(QualifiedContent.Scope.EXTERNAL_LIBRARIES)
     
    @Override
    boolean isIncremental()  
        return true
     
    @Override
    void transform(Context context,
                   Collection<TransformInput> inputs,
                   Collection<TransformInput> referencedInputs,
                   TransformOutputProvider outputProvider,
                   boolean isIncremental) throws IOException, TransformException, InterruptedException  
        // We should do something here
     
 
// Register the transform
android.registerTransform(new PatchXWalkTransform(logger))

The getInputTypes() method should return the set of types of data consumed by the transform. In our case, we want to transform classes. Another possibility is to transform resources. The getScopes() method should return a set of scopes for the transform. In our case, we are only interested by the external libraries. It s also possible to transform our own classes. The isIncremental() method returns true because we support incremental builds. The transform() method is expected to take all the provided inputs and copy them (with or without modifications) to the location supplied by the output provider. We didn t implement this method yet. This causes the removal of all external dependencies from the application.

Noop transform To keep all external dependencies unmodified, we must copy them:

@Override
void transform(Context context,
               Collection<TransformInput> inputs,
               Collection<TransformInput> referencedInputs,
               TransformOutputProvider outputProvider,
               boolean isIncremental) throws IOException, TransformException, InterruptedException  
    inputs.each  
        it.jarInputs.each  
            def jarName = it.name
            def src = it.getFile()
            def dest = outputProvider.getContentLocation(jarName, 
                                                         it.contentTypes, it.scopes,
                                                         Format.JAR);
            def status = it.getStatus()
            if (status == Status.REMOVED)   //  
                logger.info("Remove $ src ")
                FileUtils.delete(dest)
              else if (!isIncremental   status != Status.NOTCHANGED)   //  
                logger.info("Copy $ src ")
                FileUtils.copyFile(src, dest)
             
         
     
 

We also need two additional imports:

import com.android.build.api.transform.Status
import org.apache.commons.io.FileUtils

Since we are handling external dependencies, we only have to manage JAR files. Therefore, we only iterate on jarInputs and not on directoryInputs. There are two cases when handling incremental build: either the file has been removed ( ) or it has been modified ( ). In all other cases, we can safely assume the file is already correctly copied.

JAR patching When the external dependency is the Crosswalk JAR file, we also need to modify it. Here is the first part of the code (replacing ):

if ("$ src " ==~ ".*/org.xwalk/xwalk_core.*/classes.jar")  
    def pool = new ClassPool()
    pool.insertClassPath("$ src ")
    def ctc = pool.get('org.xwalk.core.internal.SslUtil') //  
    def ctm = ctc.getDeclaredMethod('shouldDenyRequest')
    ctc.removeMethod(ctm) //  
    ctc.addMethod(CtNewMethod.make("""
public static boolean shouldDenyRequest(int error)  
    return false;
 
""", ctc)) //  
    def sslUtilBytecode = ctc.toBytecode() //  
    // Write back the JAR file
    //  
  else  
    logger.info("Copy $ src ")
    FileUtils.copyFile(src, dest)
 

We also need the following additional imports to use Javassist:

import javassist.ClassPath
import javassist.ClassPool
import javassist.CtNewMethod

Once we have located the JAR file we want to modify, we add it to our classpath and retrieve the class we are interested in ( ). We locate the appropriate method and delete it ( ). Then, we add our custom method using the same name ( ). The whole operation is done in memory. We retrieve the bytecode of the modified class in . The remaining step is to rebuild the JAR file:

def input = new JarFile(src)
def output = new JarOutputStream(new FileOutputStream(dest))
//  
input.entries().each  
    if (!it.getName().equals("org/xwalk/core/internal/SslUtil.class"))  
        def s = input.getInputStream(it)
        output.putNextEntry(new JarEntry(it.getName()))
        IOUtils.copy(s, output)
        s.close()
     
 
//  
output.putNextEntry(new JarEntry("org/xwalk/core/internal/SslUtil.class"))
output.write(sslUtilBytecode)
output.close()

We need the following additional imports:

import java.util.jar.JarEntry
import java.util.jar.JarFile
import java.util.jar.JarOutputStream
import org.apache.commons.io.IOUtils

There are two steps. In , all classes are copied to the new JAR, except the SslUtil class. In , the modified bytecode for SslUtil is added to the JAR. That s all! You can view the complete example on GitHub.

More complex method replacement In the above example, the new method doesn t use any external dependency. Let s suppose we also want to replace the sslErrorFromNetErrorCode() method from the same class with the following one:

import org.chromium.net.NetError;
import android.net.http.SslCertificate;
import android.net.http.SslError;
// In SslUtil class
public static SslError sslErrorFromNetErrorCode(int error,
                                                SslCertificate cert,
                                                String url)  
    switch(error)  
        case NetError.ERR_CERT_COMMON_NAME_INVALID:
            return new SslError(SslError.SSL_IDMISMATCH, cert, url);
        case NetError.ERR_CERT_DATE_INVALID:
            return new SslError(SslError.SSL_DATE_INVALID, cert, url);
        case NetError.ERR_CERT_AUTHORITY_INVALID:
            return new SslError(SslError.SSL_UNTRUSTED, cert, url);
        default:
            break;
     
    return new SslError(SslError.SSL_INVALID, cert, url);
 

The major difference with the previous example is that we need to import some additional classes.

Android SDK import The classes from the Android SDK are not part of the external dependencies. They need to be imported separately. The full path of the JAR file is:

androidJar = "$ android.getSdkDirectory().getAbsolutePath() /platforms/" +
             "$ android.getCompileSdkVersion() /android.jar"

We need to load it before adding the new method into SslUtil class:

def pool = new ClassPool()
pool.insertClassPath(androidJar)
pool.insertClassPath("$ src ")
def ctc = pool.get('org.xwalk.core.internal.SslUtil')
def ctm = ctc.getDeclaredMethod('sslErrorFromNetErrorCode')
ctc.removeMethod(ctm)
pool.importPackage('android.net.http.SslCertificate');
pool.importPackage('android.net.http.SslError');
//  

External dependency import We must also import org.chromium.net.NetError and therefore, we need to put the appropriate JAR in our classpath. The easiest way is to iterate through all the external dependencies and add them to the classpath.

def pool = new ClassPool()
pool.insertClassPath(androidJar)
inputs.each  
    it.jarInputs.each  
        def jarName = it.name
        def src = it.getFile()
        def status = it.getStatus()
        if (status != Status.REMOVED)  
            pool.insertClassPath("$ src ")
         
     
 
def ctc = pool.get('org.xwalk.core.internal.SslUtil')
def ctm = ctc.getDeclaredMethod('sslErrorFromNetErrorCode')
ctc.removeMethod(ctm)
pool.importPackage('android.net.http.SslCertificate');
pool.importPackage('android.net.http.SslError');
pool.importPackage('org.chromium.net.NetError');
ctc.addMethod(CtNewMethod.make(" "))
// Then, rebuild the JAR...

Happy hacking!

---

1. Before Android 4.4, the webview was severely outdated. Starting from Android 5, the webview is shipped as a separate component with updates. Embedding Crosswalk is still convenient as you know exactly which version you can rely on.
2. I hope to have this fixed in later versions.
3. This may seem harmful and you are right. However, if you have an internal CA, it is currently not possible to provide its own trust store to a webview. Moreover, the system trust store is not used either. You also may want to use TLS for authentication only with client certificates, a feature supported by Dashkiosk.
4. Crosswalk being an opensource project, an alternative would have been to patch Crosswalk source code and recompile it. However, Crosswalk embeds Chromium and recompiling the whole stuff consumes a lot of resources.

• Uploaded a new version of the debian-multimedia blends metapackages
• Uploaded the latest abcmidi
• Uploaded the latest node-process-nextick-args
• Prepared version 1.0.2 of libdrumstick for experimental, as a first step for the transition. It was sponsored by James Cowgill.
• Prepared a new node-inline-source-map package, which was sponsored by Gianfranco Costamagna.
• Uploaded kmetronome to experimental as part of the libdrumstick transition.
• Prepared a new node-js-yaml package, which was sponsored by Gianfranco Costamagna.
• Uploaded version 4.2.4 of Gramps.
• Prepared a new version of vmpk which I am going to adopt, as part of the libdrumstick transition. I tried splitting the documentation into a separate package, but this proved difficult, and in the end I missed the transition freeze deadline for Debian Stretch.
• Prepared a backport of Gramps 4.2.4, which was sponsored by IOhannes m zm lnig as Gramps is new for jessie-backports.
• Began a final push to get kosmtik packaged and into the NEW queue before the impending Debian freeze for Stretch. Unfortunately, many dependencies need updating, which also depend on packages not yet in Debian. Also pushed to finish all the new packages for node-tape, which someone else has decided to take responsibility for.
• Uploaded node-cross-spawn-async to fix a Release Critical bug.
• Prepared a new node-chroma-js package, but this is unfortunately blocked by several out of date & missing dependencies.
• Prepared a new node-husl package, which was sponsored by Gianfranco Costamagna.
• Prepared a new node-resumer package, which was sponsored by Gianfranco Costamagna.
• Prepared a new node-object-inspect package, which was sponsored by Gianfranco Costamagna.
• Removed node-string-decoder from the archive, as it was broken and turned out not to be needed anymore.
• Uploaded a fix for node-inline-source-map which was failing tests. This turned out to be due to node-tap being upgraded to version 8.0.0. J r my Lal very quickly provided a fix in the form of a Pull Request upstream, so I was able to apply the same patch in Debian.

• Prepared a merge of the latest blends package from Debian in order to be able to merge the multimedia-blends package later. This was sponsored by Daniel Holbach.
• Prepared an application to become an Ubuntu Contributing Developer. Unfortunately, this was later declined. I was completely unprepared for the Developer Membership Board meeting on IRC after my holiday. I had had no time to chase for endorsements from previous sponsors, and the application was not really clear about the fact that I was not actually applying for upload permission yet. No matter, I intend to apply again later once I have more evidence & support on my application page.
• Added my blog to Planet Ubuntu, and this will hopefully be the first post that appears there.
• Prepared a merge of the latest debian-multimedia blends meta-package package from Debian. In Ubuntu Studio, we have the multimedia-puredata package seeded so that we get all the latest Puredata packages in one go. This was sponsored by Michael Terry.
• Prepared a backport of Ardour as part of the Ubuntu Studio plan to do regular backports. This is still waiting for sponsorship if there is anyone reading this that can help with that.
• Did a tweak to the Ubuntu Studio seeds and prepared an update of the Ubuntu Studio meta-packages. However, Adam Conrad did the work anyway as part of his cross-flavour release work without noticing my bug & request for sponsorship. So I closed the bug.
• Updated the Ubuntu Studio wiki to expand on the process for updating our seeds and meta-packages. Hopefully, this will help new contributors to get involved in this area in the future.
• Took part in the testing and release of the Ubuntu Studio Trusty 14.04.5 point release.
• Took part in the testing and release of the Ubuntu Studio Yakkety Beta 1 release.
• Prepared a backport of Ansible but before I could chase up what to do about the fact that ansible-fireball was no longer part of the Ansible package, some one else did the backport without noticing my bug. So I closed the bug.
• Prepared an update of the Ubuntu Studio meta-packages. This was sponsored by Jeremy Bicha.
• Prepared an update to the ubuntustudio-default-settings package. This switched the Ubuntu Studio desktop theme to Numix-Blue, and reverted some commits to drop the ubuntustudio-lightdm-theme package fom the archive. This had caused quite a bit of controversy and discussion on IRC due to the transition being a little too close to the release date for Yakkety. This was sponsored by Iain Lane (Laney).
• Prepared the Numix Blue update for the ubuntustudio-lightdm-theme package. This was also sponsored by Iain Lane (Laney). I should thank Krytarik here for the initial Numix Blue theme work here (on the lightdm theme & default settings packages).
• Provided a patch for gfxboot-theme-ubuntu which has a bug which is regularly reported during ISO testing, because the Try Ubuntu Studio without installing option was not a translatable string and always appeared in English. Colin Watson merged this, so hopefully it will be translated by the time of the next release.
• Took part in the testing and release of the Ubuntu Studio Yakkety 16.10 release.
• After a hint from Jeremy Bicha, I prepared a patch that adds a desktop file for Imagemagick to the ubuntustudio-default-settings package. This will give us a working menu item in Ubuntu Studio whilst we wait for the bug to be fixed upstream in Debian. Next month I plan to finish the ubuntustudio-lightdm-theme, ubuntustudio-default-settings transition, including dropping ubuntustudio-lightdm-theme from the Ubuntu Studio seeds. I will include this fix at the same time.

• At other times when I have had a spare moment, I have been working on resurrecting my old Family History website. It was originally produced in my Windows XP days, and I was no longer able to edit it in Linux. I decided to convert it to Jekyll. First I had to extract the old HTML from where the website is hosted using the HTTrack Website Copier. Now, I am in the process of switching the structure to the standard Jekyll template approach. I will need to switch to a nice Jekyll based theme, as as the old theming was pretty complex. I pushed the code to my Github repository for safe keeping.

• Ensure node-tape makes it through into Stretch.
• Work on all the dependencies needed to get kosmtik into Stretch.
• Convert Cree.py from QT4 to QT5 to allow it to re-enter Stretch.

• Add the Ubuntu Studio Manual Testsuite to the package tracker, and try to encourage some testing of the newest versions of our priority packages.
• Finish the ubuntustudio-lightdm-theme, ubuntustudio-default-settings transition including an update to the ubuntustudio-meta packages.
• Reapply to become a Contributing Developer.
• Start working on an Ubuntu Studio package tracker website so that we can keep an eye on the status of the packages we are interested in.

• Continue working to convert my Family History website to Jekyll.
• Try and resurrect my old Gammon one-name study Drupal website from a backup and push it to the new GoONS Website project.

• [DLA 696-1] bind9 security update for one CVE
• [DLA 711-1] curl security update for nine CVEs

• Started work on a Python API to the UK Postbox mail scanning and forwarding service. (repo)
• Lots of improvements to buildinfo.debian.net, my experiment into how to process, store and distribute .buildinfo files after the Debian archive software has processed them, including making GPG signatures mandatory (#7), updating jenkins.debian.net to sign them and moving to SSL.
• Improved the Django client to the KeyError error tracking software, enlarging the test coverage and additionally adding support for grouping errors using a context manager.
• Made a number of improvements to travis.debian.net, my hosted service for projects that host their Debian packaging on GitHub to use the Travis CI continuous integration platform to test builds on every code change:
  • Install build-dependencies with debugging output. Thanks to @waja. (#31)
  • Install Lintian by default. Thanks to @freeekanayaka. (#33).
  • Call mktemp with --dry-run to avoid having to delete it later. (commit)
• Submitted a pull request to Wheel (a utility to package Python libraries) to make the output of METADATA files reproducible. (#73)
• Submitted some miscellaneous documentation updates to the Tails operating system. (patches)

• All our websites are server by https only
• All our releases are PGP signed
• We actively encourage users to verify the downloaded files
• All new Git tags are PGP signed as well

Filed under: Debian English phpMyAdmin SUSE 0 comments

• Sandboxing now removes some environment variables like TMP from the environment.
• Several improvements to installation ordering.
• Support for armored GPG keys in trusted.gpg.d.
• Various other fixes

preseed/early_command="anna-install eatmydata-udeb"

Signal on Jolla Now in Philadelphia, people urged me to use the Signal messenger, and I was convinced by its support for good end-to-end crypto, while still supporting offline messages and allowing me to switch from my phone to my desktop and back during a conversation. The official Signal app uses Google Cloud Messaging (GCM, part of Google Play Services) to get push updates about new posts, and while I do not oppose this use of Google services (it really is just a ping without any metadata), this is a problem on Sailfish OS. Luckily, the Signal client is open source, and someone created a LibreSignal edition that replaced the use of GCM with websockets, and indeed, this worked on my phone, and I could communicate. Things were not ideal, though: I would often have to restart the app to get newly received messages; messages that I send via Signal Desktop would often not show up on the phone and, most severe, basically after every three messages, sending more messages from Desktop would stop working for my correspondents, which freaked them out. (Strangely it continued working from their phone app, so we coped for a while.) So again, my choice of non-standard devices causes inconveniences to others. This, and the fact that the original authors of Signal and the maintainers of LibreSignal got into a fight that ended LibreSignal discontinued, meant that I have to change something about this situation. I was almost ready to give in and get myself a Samsung S7 or something boring of the sort, but then I decided to tackle this issue once more, following some of the more obscure instructions out there, trying to get vanilla Signal working on my phone. About a day later, I got it, and this is how I did it.

microG So I need Google Play Services somehow, but installing the real thing did not seem to be very promising (I tried, and regularly got pop-ups telling me that Play Services has crashed.) But I found some references to a project called microG , which is an independent re-implementation of (some of) of the play services, in particular including GCM. Installing microG itself was easy, as you can add their repository to F-Droid. I installed the core services, the services framework and the fake store apps. If this had been all that was to do, things would be easy!

Play Store detection work arounds But Signal would still complain about the lack of Google Play Services. It asks Android if an app with a certain name is installed, and would refuse to work if this app does not exist. For some reason, the microG apps cannot just have the names of the real Google apps. There seem to be two ways of working around this: Patching Signal, or enabling Signature Spoofing. The initially most promising instructions (which are in a README in a tarball on a fishy file hoster linked from an answer on the Jolla support forum ) suggested patching Signal, and actually came both with a version of an app called Lucky Patcher as well as a patched Android package, but both about two years old. I tried a recent version of the Lucky Patcher, but it failed to patch the current version of Signal.

Signature Spoofing So on to Signature Spoofing. This is a feature of some non-standard Android builds that allow apps (such as microG) to fake the existence of other apps (the Play Store), and is recommended by the microG project. Sailfish OS s Android compatibility layer Alien Dalvik does not support it out of the box, but there is a tool tingle that adds this feature to existing Android systems. One just has to get the /system/framework/framework.jar file, put it into the input folder of this project, run python main.py, select 2, and copy the framework.jar from output/ back. Great.

Deodexing Alien Dalvik Only that it only works on deodexed files. I did not know anything about odexed Android Java classes (and did not really want to know), but there was not way around. Following this explanation I gathered that one finds files foo.odex in the Android system folder, runs some tool on them to create a classes.dex file, and adds that to the corresponding foo.jar or foo.apk file, copies this back to the phone and deletes the foo.odex file. The annoying this is that one does not only have to do it for framework.jar in order to please tingle, because if one does it to one odex file, one has to do to all! It seems that for people using Windows, the Universal Deodexer V5 seems to be a convenient tool, but I had to go more manually. So I first fetched smali , compiled it using ./gradlew build. Then I fetched the folders /opt/alien/system/framework and /opt/alien/system/app from the phone (e.g. using scp). Keep a backup of these in case something breaks. Then I ran these commands (disclaimer: I fetched these from my bash history and slightly cleaned them up. This is not a fire-and-forget script! Use it when you know what it and you are doing):

cd framework
for file in *.odex
do
  java -jar ~/build/smali/baksmali/build/libs/baksmali.jar deodex $file -o out
  java -jar ~/build/smali/smali/build/libs/smali.jar a out -o classes.dex
  zip -u $(basename $file .odex).jar classes.dex
  rm -rf out classes.dex $file
done
cd ..
cd app
for file in *.odex
do
  java -jar ~/build/smali/baksmali/build/libs/baksmali.jar deodex -d ../framework $file -o out
  java -jar ~/build/smali/smali/build/libs/smali.jar a out -o classes.dex
  zip -u $(basename $file .odex).apk classes.dex
  rm -rf out classes.dex $file
done
cd ..

The resulting framework.jar can now be patched with tingle:

mv framework/framework.jar ~/build/tingle/input
cd ~/build/tingle
./main.py
# select 2
cd -
mv ~/build/tingle/output/framework.jar framework/framework.jar

Now I copy these framework and app folders back on my phone, and restart Dalvik:

devel-su systemctl restart aliendalvik.service

It might start a bit slower than usually, but eventually, all the Android apps should work as before. The final bit that was missing in my case was that I had to reinstall Signal: If it is installed before microG is installed, it does not get permission to use GCM, and when it tries (while registering: After generating the keys) it just crashes. I copied /data/data/org.thoughtcrime.secretsms/ before removing Signal and moved it back after (with cp -a to preserve permissions) so that I could keep my history. And now, it seems, vanilla Signal is working just fine on my Jolla phone!

What s missing Am I completely happy with Signal? No! An important feature that it is lacking is a way to get out all data (message history including media files) in a file format that can be read without Signal; e.g. YAML files or clean HTML code. I do want to be able to re-read some of the more interesting conversations when I am 74 or 75, and I doubt that there will be a Signal App, or even Android, then. I hope that this becomes available in time, maybe in the Desktop version. I would also hope that pidgin gets support to the Signal protocol, so that I conveniently use one program for all my messaging needs on the desktop. Finally it would be nice if my Signal identity was less tied to one phone number. I have a German and a US phone number, and would want to be reachable under both on all my clients. (If you want to contact me on Signal, use my US phone number.)

Alternatives Could I have avoided this hassle by simply convincing people to use something other than Signal? Tricky, at the moment. Telegram (which works super reliable for me, and has a pidgin plugin) has dubious crypto and does not support crypto while using multiple clients. Threema has no desktop client that I know of. OTR on top of Jabber does not support offline messages. So nothing great seems to exist right now. In the long run, the best bet seems to be OMEMO (which is, in essence, the Signal protocol) on top of Jabber. It is currently supported by one Android Jabber client (Conversations) and one Desktop application (gajim, via a plugin). I should keep an eye on pidgin support for OMEMO and other development around this.