Category Archives: Stuffs corner

Configuring Apache server with LDAP for authentication and authorization

This post provides an example configuration of Apache http server to be used to serve downloading requests which are authenticated and authorized using LDAP.

Requirements:

  • Setup an Apache http server to expose files from a particular directory of a Linux-based server to outside, specifically, to the network the server is on.
  • Only https traffic is allowed
  • Requests to server have to be authenticated and authorized

Implementation:

  • OS used is CentOS ($ cat /etc/redhat-release => CentOS Linux release 7.2.1511 (Core))
  • Apache 2.4.6 ($ httpd -v => Server version: Apache/2.4.6 (CentOS))
  • Authenticate the user and check if the user is in a ldap group before granting access.
  • Put the intermediate ssl certificate chain into intermediate.pem file
  • LDAP info:
    • LDAP URL: ldaps://duyhats.ldap.com:636/ou=duyhats.com?mail?sub?(objectClass=*)
    • LDAP group: duyhatsgroup
    • cn=duyhatsgroup,ou=memberlist,ou=enterprisegroups,o=duyhats.com

Disable SELinux config in /etc/sysconfig/selinux :


# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of three two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected.
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

Here is the VirtualHost configuration part:


<VirtualHost _default_:443>
  ErrorLog logs/tls_error.log
  LogLevel debug
  SSLEngine On
  SSLProtocol all -SSLv2
  SSLCipherSuite HIGH:MEDIUM
  SSLCertificateFile /etc/httpd/conf/cert.crt
  SSLCertificateKeyFile /etc/httpd/conf/cert.key
  SSLCertificateChainFile /etc/httpd/conf/intermediate.pem
  ServerName duyhats.com
  Alias "/data" "/location/of/files"
  <Location "/data">
    AuthType basic
    AuthName "duyhats"
    AuthBasicProvider ldap
    AuthLDAPUrl "ldaps://duyhats.ldap.com:636/ou=duyhats.com?mail?sub?(objectClass=*)"
    Options Indexes FollowSymLinks
    AuthLDAPBindAuthoritative off
    Require ldap-group cn=duyhatsgroup,ou=memberlist,ou=enterprisegroups,o=duyhats.com
    Order deny,allow
  </Location>
</VirtualHost>

The whole /etc/http/conf/httpd.conf file:


#
# This is the main Apache HTTP server configuration file.  It contains the
# configuration directives that give the server its instructions.
# See <URL:http://httpd.apache.org/docs/2.4/> for detailed information.
# In particular, see
# <URL:http://httpd.apache.org/docs/2.4/mod/directives.html>
# for a discussion of each configuration directive.
#
# Do NOT simply read the instructions in here without understanding
# what they do.  They're here only as hints or reminders.  If you are unsure
# consult the online docs. You have been warned.
#
# Configuration and logfile names: If the filenames you specify for many
# of the server's control files begin with "/" (or "drive:/" for Win32), the
# server will use that explicit path.  If the filenames do *not* begin
# with "/", the value of ServerRoot is prepended -- so 'log/access_log'
# with ServerRoot set to '/www' will be interpreted by the
# server as '/www/log/access_log', where as '/log/access_log' will be
# interpreted as '/log/access_log'.

#
# ServerRoot: The top of the directory tree under which the server's
# configuration, error, and log files are kept.
#
# Do not add a slash at the end of the directory path.  If you point
# ServerRoot at a non-local disk, be sure to specify a local disk on the
# Mutex directive, if file-based mutexes are used.  If you wish to share the
# same ServerRoot for multiple httpd daemons, you will need to change at
# least PidFile.
#
ServerRoot "/etc/httpd"

#
# Listen: Allows you to bind Apache to specific IP addresses and/or
# ports, instead of the default. See also the <VirtualHost>
# directive.
#
# Change this to Listen on specific IP addresses as shown below to
# prevent Apache from glomming onto all bound IP addresses.
#
#Listen 12.34.56.78:80
Listen 443 https

#
# Dynamic Shared Object (DSO) Support
#
# To be able to use the functionality of a module which was built as a DSO you
# have to place corresponding `LoadModule' lines at this location so the
# directives contained in it are actually available _before_ they are used.
# Statically compiled modules (those listed by `httpd -l') do not need
# to be loaded here.
#
# Example:
# LoadModule foo_module modules/mod_foo.so
#
Include conf.modules.d/*.conf

#
# If you wish httpd to run as a different user or group, you must run
# httpd as root initially and it will switch.
#
# User/Group: The name (or #number) of the user/group to run httpd as.
# It is usually good practice to create a dedicated user and group for
# running httpd, as with most system services.
#
User apache
Group apache

# 'Main' server configuration
#
# The directives in this section set up the values used by the 'main'
# server, which responds to any requests that aren't handled by a
# <VirtualHost> definition.  These values also provide defaults for
# any <VirtualHost> containers you may define later in the file.
#
# All of these directives may appear inside <VirtualHost> containers,
# in which case these default settings will be overridden for the
# virtual host being defined.
#

#
# ServerAdmin: Your address, where problems with the server should be
# e-mailed.  This address appears on some server-generated pages, such
# as error documents.  e.g. admin@your-domain.com
#
ServerAdmin dnguyenv@us.ibm.com

#
# ServerName gives the name and port that the server uses to identify itself.
# This can often be determined automatically, but we recommend you specify
# it explicitly to prevent problems during startup.
#
# If your host doesn't have a registered DNS name, enter its IP address here.
#
ServerName duyhats.com

#
# Deny access to the entirety of your server's filesystem. You must
# explicitly permit access to web content directories in other
# <Directory> blocks below.
#
#<Directory />
#    AllowOverride none
#    Require all denied
#</Directory>

#
# Note that from this point forward you must specifically allow
# particular features to be enabled - so if something's not working as
# you might expect, make sure that you have specifically enabled it
# below.
#

#
# DocumentRoot: The directory out of which you will serve your
# documents. By default, all requests are taken from this directory, but
# symbolic links and aliases may be used to point to other locations.
#
DocumentRoot "/var/www/html"
#
# Relax access to content within /var/www.
#
<Directory "/var/www">
AllowOverride None
# Allow open access:
Require all granted
</Directory>
# Further relax access to the default document root:
<Directory "/var/www/html">
#
# Possible values for the Options directive are "None", "All",
# or any combination of:
#   Indexes Includes FollowSymLinks SymLinksifOwnerMatch ExecCGI MultiViews
#
# Note that "MultiViews" must be named *explicitly* --- "Options All"
# doesn't give it to you.
#
# The Options directive is both complicated and important.  Please see
# http://httpd.apache.org/docs/2.4/mod/core.html#options
# for more information.
#
Options Indexes FollowSymLinks

#
# AllowOverride controls what directives may be placed in .htaccess files.
# It can be "All", "None", or any combination of the keywords:
#   Options FileInfo AuthConfig Limit
#
AllowOverride None

#
# Controls who can get stuff from this server.
#
Require all granted
</Directory>

#
# DirectoryIndex: sets the file that Apache will serve if a directory
# is requested.
#
<IfModule dir_module>
DirectoryIndex index.html
</IfModule>

#
# The following lines prevent .htaccess and .htpasswd files from being
# viewed by Web clients.
#
<Files ".ht*">
Require all denied
</Files>

#
# ErrorLog: The location of the error log file.
# If you do not specify an ErrorLog directive within a <VirtualHost>
# container, error messages relating to that virtual host will be
# logged here.  If you *do* define an error logfile for a <VirtualHost>
# container, that host's errors will be logged there and not here.
#
ErrorLog "logs/error_log"

#
# LogLevel: Control the number of messages logged to the error_log.
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
#
LogLevel warn

<IfModule log_config_module>
#
# The following directives define some format nicknames for use with
# a CustomLog directive (see below).
#
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %b" common

<IfModule logio_module>
# You need to enable mod_logio.c to use %I and %O
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio
</IfModule>

#
# The location and format of the access logfile (Common Logfile Format).
# If you do not define any access logfiles within a <VirtualHost>
# container, they will be logged here.  Contrariwise, if you *do*
# define per-<VirtualHost> access logfiles, transactions will be
# logged therein and *not* in this file.
#
#CustomLog "logs/access_log" common

#
# If you prefer a logfile with access, agent, and referer information
# (Combined Logfile Format) you can use the following directive.
#
CustomLog "logs/access_log" combined
</IfModule>

<IfModule alias_module>
#
# Redirect: Allows you to tell clients about documents that used to
# exist in your server's namespace, but do not anymore. The client
# will make a new request for the document at its new location.
# Example:
# Redirect permanent /foo http://www.example.com/bar

#
# Alias: Maps web paths into filesystem paths and is used to
# access content that does not live under the DocumentRoot.
# Example:
# Alias /webpath /full/filesystem/path
#
# If you include a trailing / on /webpath then the server will
# require it to be present in the URL.  You will also likely
# need to provide a <Directory> section to allow access to
# the filesystem path.

#
# ScriptAlias: This controls which directories contain server scripts.
# ScriptAliases are essentially the same as Aliases, except that
# documents in the target directory are treated as applications and
# run by the server when requested rather than as documents sent to the
# client.  The same rules about trailing "/" apply to ScriptAlias
# directives as to Alias.
#
ScriptAlias /cgi-bin/ "/var/www/cgi-bin/"

</IfModule>

#
# "/var/www/cgi-bin" should be changed to whatever your ScriptAliased
# CGI directory exists, if you have that configured.
#
<Directory "/var/www/cgi-bin">
AllowOverride None
Options None
Require all granted
</Directory>

<IfModule mime_module>
#
# TypesConfig points to the file containing the list of mappings from
# filename extension to MIME-type.
#
TypesConfig /etc/mime.types

#
# AddType allows you to add to or override the MIME configuration
# file specified in TypesConfig for specific file types.
#
#AddType application/x-gzip .tgz
#
# AddEncoding allows you to have certain browsers uncompress
# information on the fly. Note: Not all browsers support this.
#
#AddEncoding x-compress .Z
#AddEncoding x-gzip .gz .tgz
#
# If the AddEncoding directives above are commented-out, then you
# probably should define those extensions to indicate media types:
#
AddType application/x-compress .Z
AddType application/x-gzip .gz .tgz

#
# AddHandler allows you to map certain file extensions to "handlers":
# actions unrelated to filetype. These can be either built into the server
# or added with the Action directive (see below)
#
# To use CGI scripts outside of ScriptAliased directories:
# (You will also need to add "ExecCGI" to the "Options" directive.)
#
#AddHandler cgi-script .cgi

# For type maps (negotiated resources):
#AddHandler type-map var

#
# Filters allow you to process content before it is sent to the client.
#
# To parse .shtml files for server-side includes (SSI):
# (You will also need to add "Includes" to the "Options" directive.)
#
AddType text/html .shtml
AddOutputFilter INCLUDES .shtml
</IfModule>

#
# Specify a default charset for all content served; this enables
# interpretation of all content as UTF-8 by default.  To use the
# default browser choice (ISO-8859-1), or to allow the META tags
# in HTML content to override this choice, comment out this
# directive:
#
AddDefaultCharset UTF-8

<IfModule mime_magic_module>
#
# The mod_mime_magic module allows the server to use various hints from the
# contents of the file itself to determine its type.  The MIMEMagicFile
# directive tells the module where the hint definitions are located.
#
MIMEMagicFile conf/magic
</IfModule>

#
# Customizable error responses come in three flavors:
# 1) plain text 2) local redirects 3) external redirects
#
# Some examples:
#ErrorDocument 500 "The server made a boo boo."
#ErrorDocument 404 /missing.html
#ErrorDocument 404 "/cgi-bin/missing_handler.pl"
#ErrorDocument 402 http://www.example.com/subscription_info.html
#

#
# EnableMMAP and EnableSendfile: On systems that support it,
# memory-mapping or the sendfile syscall may be used to deliver
# files.  This usually improves server performance, but must
# be turned off when serving from networked-mounted
# filesystems or if support for these functions is otherwise
# broken on your system.
# Defaults if commented: EnableMMAP On, EnableSendfile Off
#
#EnableMMAP off
EnableSendfile on

# Supplemental configuration
#
# Load config files in the "/etc/httpd/conf.d" directory, if any.
IncludeOptional conf.d/*.conf
<VirtualHost _default_:443>
  ErrorLog logs/tls_error.log
  LogLevel debug
  SSLEngine On
  SSLProtocol all -SSLv2
  SSLCipherSuite HIGH:MEDIUM
  SSLCertificateFile /etc/httpd/conf/cert.crt
  SSLCertificateKeyFile /etc/httpd/conf/cert.key
  SSLCertificateChainFile /etc/httpd/conf/intermediate.pem
  ServerName duyhats.com
  Alias "/data" "/location/of/files"
  <Location "/data">
    AuthType basic
    AuthName "duyhats"
    AuthBasicProvider ldap
    AuthLDAPUrl "ldaps://duyhats.ldap.com:636/ou=duyhats.com?mail?sub?(objectClass=*)"
    Options Indexes FollowSymLinks
    AuthLDAPBindAuthoritative off
    Require ldap-group cn=duyhatsgroup,ou=memberlist,ou=enterprisegroups,o=duyhats.com
    Order deny,allow
  </Location>
</VirtualHost>

Change default Docker folder

On Linux based machine, Docker uses /var/lib/docker as default home directory for all IO activities. Sometimes you don’t want your images, containers, etc going into that directory but other one eg /opt/docker

Here are some quick steps to make it happen (This example is on CentOS)


mkdir /opt/docker

vi /etc/sysconfig/docker

Then change other_args=”” configuration to be


# /etc/sysconfig/docker
#
# Other arguments to pass to the docker daemon process
# These will be parsed by the sysv initscript and appended
# to the arguments list passed to docker -d

other_args="-g /opt/docker"

Then restart docker

service docker stop
service docker start

If you want Docker to automatically start when your machine starts:

chkconfig docker on

Share a folder from a host Mac OS to a VirtualBox Linux guest

If you’re using VirtualBox to run a VM on your Mac OS, you may already see that the /Users folder of the Mac is by default shared to the guest system. But you may need to share a different folder of the host Mac OS to the guest. In that case, follow these quick steps:

– In VirtualBox, select the VM instance of the guest system then click on Settings

– Click on Shared Folders icon

– Add a new item for Machine Folders list

– In Folder Path, enter or Click on the dropdown list to browse the folder of the Mac OS you want to share. Eg: <host-folder-path>

– In the Folder Name box, enter the name for that folder. Eg: <host-folder>

– Check Auto-mount and Make Permanent boxes

– SSH to the Linux guest system. Eg: If you’re using docker machine:

$ docker-machine ssh default (default is the name of the VM)

– Create a folder on the guest system:

$ mkdir -p /path/on/guest 

– Then do the mount:

 $ sudo mount -t vboxsf <host-folder> /path/on/guest 

Installing docker on Mac

This post provides some quick steps to install Docker on a Mac

1. Install Virtual box

Follow instruction from this link to install Virtual box first

2. Install boot2docker and docker

Go to the official Docker site to install, or from homebrew. This instruction is for those who want to use homebrew:

Note: Make sure you have hombrew installed upfront, if not, do below steps first:

– Install Xcode from Apple App Store

– Install necessary utilities from Apple:

$xcode-select install

Once you have the utilities which include curl, run the command below:

$ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Now you have brew, run:

$brew update
$brew install docker
$brew install boot2docker

3. Initiate boot2docker

$boot2docker init

then

$boot2docker start

3. Set necessary environments variables

$export DOCKER_HOST=tcp://192.168.2.144:2375

Note: The ip address above should be different for your environment. Take what `boot2docker up` command recommends. 

Troubles shooting:

  1. error in run: Failed to initialize machine “boot2docker-vm”: exit status 1

Run $boot2docker init -v for details

In many cases, it’s because permission problem. Try to delete this file /path/to/boot2docker-vm/boot2docker-vm.vbox then try again

  1. docker-machine create hangs at: Daemon not responding yet: dial tcp your_specific_ip: operation timed out

That’s Virtualbox problem, the latest test version (5.0.3) solves this issue.