[AMBARI-18526] Ambari breaks sudo and user access if Ambari Agent misconfigured

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.0
• Fix Version/s: 2.4.2
• Component/s: ambari-server
• Assignee: Dmitry Lysnichenko
• Reporter: Dmitry Lysnichenko
• Created: 04/Oct/16 15:32
• Updated: 06/Oct/16 20:09
• Resolved: 06/Oct/16 17:03

Description

While working on Ambari installation using Vagrant I found following issues that can be potentially dangerous and destroy sudo and /home permissions

Steps to reproduce:

Remove or misconfigure following configs from ambari-agent.ini file:

[agent]
logdir=/var/log/ambari-agent
piddir=/var/run/ambari-agent

Start ambari agent. Note that log, pid, and out want to be written to /. Everything fails and sudo is destroyed as well as /home for all users. Sudo user will not be able to connect to cluster using private key due to permissions and folder ownership switch to root.

[root@ambari-slave1 vagrant]# id
uid=0(root) gid=0(root) groups=0(root)

[root@ambari-slave1 vagrant]# ambari-agent start

chown: changing ownership of `/proc/12937': Operation not permitted
chown: changing ownership of `/proc/12938/task/12938': Operation not permitted
chown: changing ownership of `/proc/12938': Operation not permitted
chown: changing ownership of `/proc/12941/task/12941': Operation not permitted
chown: changing ownership of `/proc/12941': Operation not permitted
chown: changing ownership of `/proc/12942/task/12942/fd/4': No such file or directory
chown: changing ownership of `/proc/12942/task/12942/fdinfo/4': No such file or directory
chown: changing ownership of `/proc/12942/task/12942': Operation not permitted
chown: changing ownership of `/proc/12942/fd/4': No such file or directory
chown: changing ownership of `/proc/12942/fdinfo/4': No such file or directory
chown: changing ownership of `/proc/12942': Operation not permitted
Starting ambari-agent
Verifying ambari-agent process status...
Ambari Agent successfully started
Agent PID at: /ambari-agent.pid
Agent out at: /ambari-agent.out
Agent log at: /ambari-agent.log

Sticky bit is removed from sudo as result of it

[root@ambari-slave1 vagrant]# ls -l /usr/bin/sudo
---x--x--x. 1 root root 123832 Oct 15  2014 /usr/bin/sudo

it should be:

[root@ambari-slave2 vagrant]# ls -l /usr/bin/sudo
---s--x--x. 1 root root 123832 Oct 15  2014 /usr/bin/sudo

All user folder is messed up as owned by root

[root@ambari-slave1 vagrant]# ls -ld /home/
drwxr-xr-x. 3 root root 4096 Mar  9  2016 /home/

[root@ambari-slave1 vagrant]# ls -ld /home/vagrant
drwx------ 3 root root 4096 Sep 27 22:16 /home/vagrant

sudo is broken:

[root@ambari-slave1 vagrant]# id
uid=0(root) gid=0(root) groups=0(root)
[root@ambari-slave1 vagrant]# exit
exit
[vagrant@ambari-slave1 ~]$ sudo su
sudo: effective uid is not 0, is sudo installed setuid root?

this is caused due to by function in /usr/sbin/ambari-agent

get_agent_property() {
property_name="$1"
value=$(awk -F "=" "/$property_name/ {print \$2}" /etc/ambari-agent/conf/ambari-agent.ini)
echo $value
}

Issue Links

• links to: review_request_