----
 Password Encryption
 -----
 Oleg Gusakov
 Robert Scholte
 -----
 2014-03-23
 ------

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~~ to you under the Apache License, Version 2.0 (the
~~ "License"); you may not use this file except in compliance
~~ with the License.  You may obtain a copy of the License at
~~
~~   http://www.apache.org/licenses/LICENSE-2.0
~~
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~~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
~~ KIND, either express or implied.  See the License for the
~~ specific language governing permissions and limitations
~~ under the License.

~~ NOTE: For help with the syntax of this file, see:
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{Password Encryption}

  [[1]] {{{Introduction}Introduction}}

  [[2]] {{{How_to_create_a_master_password}How to create a master password}}

  [[3]] {{{How_to_encrypt_server_passwords}How to encrypt server passwords}}

  [[4]] {{{How_to_keep_the_master_password_on_removable_drive}How to keep the master password on removable drive}}

  [[5]] {{{Tips}Tips}}


* {Introduction}

 Maven 2.1.0+ now supports server password encryption. The main use case, addressed by this solution is:

   * multiple users share the same build machine (server, CI box)

   * some users have the privilege to deploy Maven artifacts to repositories, some don't.

      ** this applies to any server operations, requiring authorization, not only deployment

   * <<<settings.xml>>> is shared between users

 The implemented solution adds the following capabilities:

   * authorized users have an additional <<<settings-security.xml>>> file in their <<<~/.m2>>> folder

      ** this file either contains encrypted <<master password>>, used to encrypt other passwords

      ** or it can contain a <<relocation>> - reference to another file, possibly on removable storage

      ** this password is created first via CLI for now

   * server entries in the <<<settings.xml>>> have passwords and/or keystore passphrases encrypted

      ** for now - this is done via CLI <<after>> master password has been created and stored in appropriate location

* {How to create a master password}

 Use the following command line:

+------------------------------------+
mvn --encrypt-master-password <password>
+------------------------------------+

 <Note:> Since Maven 3.2.1 the password is an optional argument. If not provided, Maven will prompt for the password. 
         Earlier versions of Maven will not prompt for a password, so it must be typed on the command-line in plaintext. See {{{Tips}Tips}} below for more information.

 This command will produce an encrypted version of the password, something like

+------------------------------------+
{jSMOWnoPFgsHVpMvz5VrIt5kRbzGpI8u+9EF1iFQyJQ=}
+------------------------------------+

 Store this password in the <<<~/.m2/settings-security.xml>>>; it should look like

+------------------------------------+
<settingsSecurity>
  <master>{jSMOWnoPFgsHVpMvz5VrIt5kRbzGpI8u+9EF1iFQyJQ=}</master>
</settingsSecurity>
+------------------------------------+

 When this is done, you can start encrypting existing server passwords.

* {How to encrypt server passwords}

 You will have to use the following command line:

+------------------------------------+
mvn --encrypt-password <password>
+------------------------------------+

  <Note:>Just like <<<--encrypt-master-password>>> the password argument is optional since Maven 3.2.1.
  
  This command will produce an encrypted version of it, something like

+------------------------------------+
{COQLCE6DU6GtcS5P=}
+------------------------------------+

 Cut-n-paste it into your <<<settings.xml>>> file in the server section. This will look like:

+------------------------------------+
<settings>
...
  <servers>
...
    <server>
      <id>my.server</id>
      <username>foo</username>
      <password>{COQLCE6DU6GtcS5P=}</password>
    </server>
...
  </servers>
...
</settings>
+------------------------------------+

 Please note that password can contain any information outside of the curly brackets, so that the following will still work:

+------------------------------------+
<settings>
...
  <servers>
...
    <server>
      <id>my.server</id>
      <username>foo</username>
      <password>Oleg reset this password on 2009-03-11, expires on 2009-04-11 {COQLCE6DU6GtcS5P=}</password>
    </server>
...
  </servers>
...
</settings>
+------------------------------------+

 Then you can use, say, deploy plugin, to write to this server:

+------------------------------------+
mvn deploy:deploy-file -Durl=https://maven.corp.com/repo \
                       -DrepositoryId=my.server \
                       -Dfile=your-artifact-1.0.jar \
+------------------------------------+



* {How to keep the master password on removable drive}

 Create the master password exactly as described above, and store it on a
 removable drive, for instance on OSX, my USB drive mounts as <<</Volumes/mySecureUsb>>>,
 so I store

+------------------------------------+
<settingsSecurity>
  <master>{jSMOWnoPFgsHVpMvz5VrIt5kRbzGpI8u+9EF1iFQyJQ=}</master>
</settingsSecurity>
+------------------------------------+

 in the file <<</Volumes/mySecureUsb/secure/settings-security.xml>>>

 And then I create <<<~/.m2/settings-security.xml>>> with the following content:

+------------------------------------+
<settingsSecurity>
  <relocation>/Volumes/mySecureUsb/secure/settings-security.xml</relocation>
</settingsSecurity>
+------------------------------------+

 This assures that encryption will only work when the usb drive is mounted by OS.
 This addresses a use case where only certain people are authorized to deploy and
 are issued these devices.

* {Tips}

** Escaping curly-brace literals in your password <(Since: Maven 2.2.0)>

  At times, you might find that your password (or the encrypted form of it) may
  actually contain '\{' or '\}' as a literal value. If you added such a password as-is
  to your settings.xml file, you would find that Maven does strange things with it.
  Specifically, Maven will treat all the characters preceding the '\{' literal, and
  all the characters after the '\}' literal, as comments. Obviously, this is not the
  behavior you want in such a situation. What you really need is a way of <<escaping>>
  the curly-brace literals in your password.

  Starting in Maven 2.2.0, you can do just this, with the widely used '\' escape character.
  If your password looks like this:

+---+
jSMOWnoPFgsHVpMvz5VrIt5kRbzGpI8u+{EF1iFQyJQ=
+---+

  Then, the value you would add to your settings.xml would look like this:

+---+
{jSMOWnoPFgsHVpMvz5VrIt5kRbzGpI8u+\{EF1iFQyJQ=}
+---+

** Password Security

  Editing <<<settings.xml>>> and running the above commands can still leave your password stored
  locally in plaintext. You may want to check the following locations:

    * Shell history (e.g. by running <<<history>>>). You may want to clear your history after
      encrypting the above passwords

    * Editor caches (e.g. <<<~/.viminfo>>>)

  Also note that the encrypted passwords can be decrypted by someone that has the master password
  and settings security file. Keep this file secure (or stored separately) if you expect the
  possibility that the <<<settings.xml>>> file may be retrieved.

** Password Escaping on different platforms

  On some platforms it might be neccessary to quote your password based on the content of your
  password in particular having special characters like <<<%>>>, <<<!>>>, <<<$>>> etc. in there. 
  For example on Windows you have to be carefull about things like the following:

  The following example will not work on Windows:

+----+
mvn.bat --encrypt-master-password a!$%^b
+----+
  
  whereas the following will work on Windows:

+----+
mvn.bat --encrypt-master-password "a!$%^b"
+----+

  If you are on a linux/unix platform you should use single quotes for the above 
  master password otherwise you will be astonished that the usage of the master-password
  will not work (caused by the dollar sign and furthermore the exclamation mark).