AST-2012-004: Fix an error that allows AMI users to run shell commands sans authoriza...

AST-2012-004: Fix an error that allows AMI users to run shell commands sans authorization.

As detailed in the advisory, AMI users without write authorization for SYSTEM class AMI
actions were able to run system commands by going through other AMI commands which did
not require that authorization. Specifically, GetVar and Status allowed users to do this
by setting their variable/s options to the SHELL or EVAL functions.
Also, within 1.8, 10, and trunk there was a similar flaw with the Originate action that
allowed users with originate permission to run MixMonitor and supply a shell command
in the Data argument. That flaw is fixed in those versions of this patch.

(closes issue ASTERISK-17465)
Reported By: David Woolley
Patches:
	162_ami_readfunc_security_r2.diff uploaded by jrose (license 6182)
	18_ami_readfunc_security_r2.diff uploaded by jrose (license 6182)
	10_ami_readfunc_security_r2.diff uploaded by jrose (license 6182)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.2@363117 65c4cc65-6c06-0410-ace0-fbb531ad65f3