How the MySQL Monitor Agent broke Sendmail

For MySQL Enterprise Monitor an agent is required. I've downloaded
V23981-01.zip from https://edelivery.oracle.com which contains mysqlmonitoragent-2.3.1.2044-linux-glibc2.3-x86-64bit-installer.rpm

When I was testing the email alerting for my backup script I got an error:

/etc/mail/submit.cf: line 544: fileclass: cannot open '/etc/mail/trusted-users': Group
writable directory

Luckily RPM was able to tell me that mysqlmonitoragent had set / to the wrong permissions.

# rpm -qf /
filesystem-2.4.0-3.el5
mysqlmonitoragent-2.3.1.2044-0
# rpm -qvl mysqlmonitoragent-2.3.1.2044-0 | head -1
drwxrwxr-x    2 root    root                0 Nov 25 01:51 /
# rpm -qvl filesystem-2.4.0-3.el5 | head -1
drwxr-xr-x    2 root    root                0 Oct  1  2009 /
# echo test | mail -s test user@example.com
# /etc/mail/submit.cf: line 544: fileclass: cannot open '/etc/mail/trusted-users': Group
writable directory

I've filed Bug #60752 for this. So watch out for this bug if you're using mysqlmonitoragent RPM's!

The work-around is to do a "chmod 755 /".