Andrew Beaton :: FAQ » General

List and Install Security Updates via YUM

Andrew — Fri, 08 Jul 2011 17:04:30 +0000

You can now easily find out what security updates there are for your system (RHEL / CentOs / Fedora) by installing the ‘yum-security‘ plugin.

# yum install yum-security

To list available updates and see the relevant advisory code, use the following command:

# yum list security

To obtain information on the returned advisory codes, use the following:

# yum info-security

To list updates that are security relevent, use the following:

# yum --security check-update

And finally, to install only the security update packages, use the following:

# yum update --security

View output of the dd command

Andrew — Thu, 23 Jun 2011 10:48:36 +0000

Recently whilst wiping some old hard disks I thought it would be useful to see what the ‘dd’ command was doing, rather than sitting there blankly for hour. I knocked up a little bash script to run in another terminal that will update the terminal running dd with some useful status information.

In this example, dd will be run as…

$ dd if=/dev/random of=/dev/sda

copy the following into ddUpdate.sh for example and run it…

#!/bin/sh
 
ddpid=`ps auwx | awk '/dd if/ && !/awk/ { print $2}'`
 
while [ "$ddpid" != "" ]
do
kill -USR1 $ddpid
sleep 1
ddpid=`ps auwx | awk '/dd if/ && !/awk/ { print $2}'`
done

This outputs the following to the terminal running dd…

xxxxxx records in
xxxxxx records out
xxxxxx bytes (xx nn) copied, xxxx s, xx MB/s

Error: sec_error_reused_issuer_and_serial

Andrew — Fri, 13 Nov 2009 23:13:31 +0000

Problem

You come across the following error message when trying to browse to a secure website (SSL)

Secure Connection Failed
 
An error occurred during a connection to 192.168.12.122.
 
You have received an invalid certificate. Please contact the server administrator or email correspondent and give them the following information:
 
Your certificate contains the same serial number as another certificate issued by the certificate authority. Please get a new certificate containing a unique serial number.
 
(Error code: sec_error_reused_issuer_and_serial)
 
The page you are trying to view can not be shown because the authenticity of the received data could not be verified.
 
    * Please contact the web site owners to inform them of this problem.

Solution

If you have recieved this error and are trying to access something that has a self signed certificate, there are two places in Firefox that you must visit in order to access the particular site again.

The first visit Tools –> options –> Advanced –> View Certificates

You must remove the certificates in the “Servers” tab, then under the same location you must remove the certificate authority because it is a self signed certificate, so on the “Authorities” tab, simply find the CA for the device you are having trouble with and delete it.