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Category: Centos
- Authentication Token Manipulation Error
You may get an error, such as Authentication Token Manipulation Error, while trying to change passwords for a user. For example:
#passwd user
Authentication Token Manipulation Error
#This error is being produced because you are using shadowed password files and the shadow doesn’t have entry for this user. i.e, passwd file has an entry for this user, but shadow file doesn’t.
In order to resolve this, you can either add the entry manually or recreate the shadow file. You can use pwconv to recreate the shadow file. See the manpage for more details on this.
- How to enable Status in apache
Add this to your httpd.conf file:
ExtendedStatus On
<Location /server-status>
SetHandler server-status
Order Deny,Allow
Deny from all
Allow from 127.0.0.1
</Location> - How to clear SWAP
It happens for swap to be used from time to time :
root@servcorp:~# free -m
total used free shared buffers cached
Mem: 4011 759 3252 0 4 53
-/+ buffers/cache: 702 3309
Swap: 8191 15 8176To clear the swap run :
root@servcorp:~# swapoff -a && swapon -a
And free shows :
root@servcorp:~# free -m
total used free shared buffers cached
Mem: 4011 746 3265 0 4 55
-/+ buffers/cache: 686 3325
Swap: 8191 0 8191 - How to clear cached RAM
sync; echo 3 > /proc/sys/vm/drop_caches; echo 0 > /proc/sys/vm/drop_caches; sync
- Installing mod_suphp
Usually if you add a simple VirtualHost and set the DocumentRoot into on /home/
then its possible for some files not to be owned by that (e.g: uploaded images via web interface, php sessions..etc). A solution for this problem is to install mod_suphp which will make Apache to write in /home/
with permissions. To install mod_suphp : Download http://www.suphp.org/download/suphp-0.7.1.tar.gz
tar zxvf suphp-0.7.1.tar.gz
cd suphp-0.7.1
yum install httpd-devel
./configure --with-apxs=/usr/sbin/apxs --with-apache-user=httpd --with-logfile=/var/log/httpd/suphp.log --with-setid-mode=paranoid --sysconfdir=/etc --with-apr=/usr/bin/apr-1-config --with-php=/usr/bin/php-cgi --enable-SUPHP_USE_USERGROUP=yes
make
make install
cd /etc/httpd/conf.d/
mv php.conf php.conf.bk
Then create suphp.conf and put in it:
LoadModule suphp_module modules/mod_suphp.so
suPHP_Engine on
AddType application/x-httpd-php5 .php5 .php4 .php .php3 .php2 .phtml
suPHP_AddHandler application/x-httpd-php5
Then create /etc/suphp.conf and put in it:
; This file is parse anew by suPHP for each request
; rather than being loaded once.[global]
;Path to logfile
logfile=/var/log/httpd/suphp.log;Loglevel
loglevel=info;User Apache is running as
; MANDATORY
webserver_user=apache; Path all scripts have to be in
; This works as a prefix when a trailing slash is not specified.
; e.g. /home will match /home /home2 /home3 etc While /home/ will only match /home/
;
; Changing this to a more specific path will improve security
docroot=/;Path to chroot() to before executing script
;chroot=/home; Security options
allow_file_group_writeable=true
allow_file_others_writeable=true
allow_directory_group_writeable=true
allow_directory_others_writeable=true; Check whether script is within DOCUMENT_ROOT
; Does NOT perform this check on included scripts.
; i.e. include_once("/test3.php"); works even though it's in the root directory
;
; Changing this to true will improve security but make all php userdir requests fail
check_vhost_docroot=false; Allow the user and group specified by a ~userdir request to override the
; suPHP_UserGroup directive inside the source virtualhost
;
; Changing this to false will improve security but make some types of php userdir
; requests fail
;userdir_overrides_usergroup=true; suPHP Paranoid mode checks that the target script UID and GID match
; the UID and GID of the user running the script. To disable these
; checks change the following values to false. Without these checks, mod_suphp
; is effectively running in "Force" mode.
;paranoid_uid_check=true
;paranoid_gid_check=true;Send minor error messages to browser
errors_to_browser=false;PATH environment variable
env_path="/bin:/usr/bin";Umask to set, specify in octal notation
umask=0022; Minimum UID
;min_uid=100; Minimum GID
;min_gid=100; Normally suPHP only displays the PHP binary in process lists (ps aux).
; Setting this option to 'true' will cause suPHP to display both the
; PHP binary and the script filename.
;full_php_process_display=true[handlers]
;Handler for php-scripts
application/x-httpd-php="php:/usr/bin/php-cgi"
application/x-httpd-php4="php:/usr/php4/bin/php-cgi"
application/x-httpd-php5="php:/usr/bin/php-cgi";Handler for CGI-scripts
;x-suphp-cgi="execute:!self"[phprc_paths]
;Uncommenting these will force all requests to that handler to use the php.ini
;in the specified directory regardless of suPHP_ConfigPath settings.
;application/x-httpd-php=/usr/local/lib/
;application/x-httpd-php4=/usr/local/php4/lib/
;application/x-httpd-php5=/usr/local/lib/After this make sure that the VirtualHost contains :
suPHP_UserGroup user user
SuexecUserGroup user user
Also /etc/httpd/conf/httpd.conf should contain:
DirectoryIndex index.html.var index.htm index.html index.shtml index.xhtml index.wml index.perl index.pl index.plx index.ppl index.cgi index.jsp index.js index.jp index.php4 index.php3 index.php index.phtml default.htm default.html home.htm index.php5 Default.html Default.htm home.html
Finally do a service httpd restart
Check /var/log/httpd/suphp.log and error_log for possible errors. In my case I noticed this:
“[Fri Apr 22 14:36:55 2011] [warn] Mismatch between target UID (501) and UID (48) of file “/home/arpart/public_html/index.php”
Which means that some files were not owned by
. Use chown -R user.user /home/user to fix the problem. - Yum and RPM Tricks
This applies to Centos 5.6 but most likely it works on any rpm based distro.
1. It happened many times to mess the permissions of a file and services not to work properly. In order to get fixed I run :
rpm -qf /path/to/filerpm -qlLists all files from a package.This should show the package that contains the modified file. Then I run :
rpm --setpermsAlso this command should show a list of modified files within a package:
rpm -V2. To view the Changelog:
rpm -q --changelog| less 3. View package based on repo:
rpm -qa release="*rf*"4. Extract just one File:
rpm2cpio logrotate-1.0-1.i386.rpm |cpio -ivd etc/logrotate.conf5. Query Package Install Order and Dates
rpm -qa --last >~/RPMS_by_Install_Date6. Query Available Packages from a Repo