Added ClientAliveCountMax config parameter

README.md

@@ -242,6 +242,22 @@ This option applies to protocol version 2 only.
 
 - *Default*: '0'
 
+sshd_client_alive_count_max
+--------------------------
+ClientAliveCountMax in sshd_config.
+Sets the number of client alive messages (see below) which may be sent without sshd(8)
+receiving any messages back from the client. If this threshold is reached while client alive
+messages are being sent, sshd will disconnect the client, terminating the session.  It is
+important to note that the use of client alive messages is very different from TCPKeepAlive
+(below).  The client alive messages are sent through the encrypted channel and therefore will
+not be spoofable.  The TCP keepalive option enabled by TCPKeepAlive is spoofable.  The client
+alive mechanism is valuable when the client or server depend on knowing when a connection has
+become inactive. The default value is 3.  If ClientAliveInterval (see below) is set to 15,
+and ClientAliveCountMax is left at the default, unresponsive SSH clients will be disconnected
+after approximately 45 seconds.  This option applies to protocol version 2 only.
+
+- *Default*: '3'
+
 keys
 ----
 Hash of keys for user's ~/.ssh/authorized_keys

manifests/init.pp

@@ -42,6 +42,7 @@ class ssh (
   $sshd_allow_tcp_forwarding        = 'yes',
   $sshd_x11_forwarding              = 'yes',
   $sshd_use_pam                     = 'USE_DEFAULTS',
+  $sshd_client_alive_count_max      = '3',
   $sshd_client_alive_interval       = '0',
   $sshd_gssapiauthentication        = 'yes',
   $sshd_gssapikeyexchange           = 'USE_DEFAULTS',
@@ -323,6 +324,7 @@ class ssh (
     validate_re($sshd_use_pam_real, '^(yes|no)$', "ssh::sshd_use_pam may be either 'yes' or 'no' and is set to <${sshd_use_pam_real}>.")
   }
   if is_integer($sshd_client_alive_interval) == false { fail("ssh::sshd_client_alive_interval must be an integer and is set to <${sshd_client_alive_interval}>.") }
+  if is_integer($sshd_client_alive_count_max) == false { fail("ssh::sshd_client_alive_count_max must be an integer and is set to <${sshd_client_alive_count_max}>.") }
 
   if $sshd_config_banner != 'none' {
     validate_absolute_path($sshd_config_banner)

spec/classes/init_spec.rb

@@ -70,6 +70,7 @@ describe 'ssh' do
     it { should contain_file('sshd_config').with_content(/^X11Forwarding yes$/) }
     it { should contain_file('sshd_config').with_content(/^UsePAM yes$/) }
     it { should contain_file('sshd_config').with_content(/^ClientAliveInterval 0$/) }
+    it { should contain_file('sshd_config').with_content(/^ClientAliveCountMax 3$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPIAuthentication yes$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPICleanupCredentials yes$/) }
     it { should contain_file('sshd_config').with_content(/^HostKey \/etc\/ssh\/ssh_host_rsa_key$/) }
@@ -448,6 +449,7 @@ describe 'ssh' do
     it { should contain_file('sshd_config').with_content(/^X11Forwarding yes$/) }
     it { should contain_file('sshd_config').with_content(/^UsePAM yes$/) }
     it { should contain_file('sshd_config').with_content(/^ClientAliveInterval 0$/) }
+    it { should contain_file('sshd_config').with_content(/^ClientAliveCountMax 3$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPIAuthentication yes$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPICleanupCredentials yes$/) }
     it { should contain_file('sshd_config').with_content(/^HostKey \/etc\/ssh\/ssh_host_rsa_key$/) }
@@ -542,6 +544,7 @@ describe 'ssh' do
     it { should contain_file('sshd_config').with_content(/^X11Forwarding yes$/) }
     it { should contain_file('sshd_config').with_content(/^UsePAM yes$/) }
     it { should contain_file('sshd_config').with_content(/^ClientAliveInterval 0$/) }
+    it { should contain_file('sshd_config').with_content(/^ClientAliveCountMax 3$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPIAuthentication yes$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPICleanupCredentials yes$/) }
     it { should contain_file('sshd_config').with_content(/^HostKey \/etc\/ssh\/ssh_host_rsa_key$/) }
@@ -636,6 +639,7 @@ describe 'ssh' do
     it { should contain_file('sshd_config').with_content(/^X11Forwarding yes$/) }
     it { should contain_file('sshd_config').with_content(/^UsePAM yes$/) }
     it { should contain_file('sshd_config').with_content(/^ClientAliveInterval 0$/) }
+    it { should contain_file('sshd_config').with_content(/^ClientAliveCountMax 3$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPIAuthentication yes$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPICleanupCredentials yes$/) }
     it { should contain_file('sshd_config').with_content(/^HostKey \/etc\/ssh\/ssh_host_rsa_key$/) }
@@ -748,6 +752,7 @@ describe 'ssh' do
         :sshd_x11_forwarding             => 'no',
         :sshd_use_pam                    => 'no',
         :sshd_client_alive_interval      => '242',
+        :sshd_client_alive_count_max     => '0',
       }
     end
 
@@ -779,6 +784,7 @@ describe 'ssh' do
     it { should contain_file('sshd_config').with_content(/^X11Forwarding no$/) }
     it { should contain_file('sshd_config').with_content(/^UsePAM no$/) }
     it { should contain_file('sshd_config').with_content(/^ClientAliveInterval 242$/) }
+    it { should contain_file('sshd_config').with_content(/^ClientAliveCountMax 0$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPIAuthentication yes$/) }
     it { should contain_file('sshd_config').with_content(/^GSSAPICleanupCredentials yes$/) }
     it { should contain_file('sshd_config').with_content(/^HostKey \/etc\/ssh\/ssh_host_rsa_key$/) }
@@ -993,6 +999,25 @@ describe 'ssh' do
     end
   end
 
+  context 'with sshd_client_alive_count_max set to invalid value on valid osfamily' do
+    let :facts do
+      {
+        :fqdn      => 'monkey.example.com',
+        :osfamily  => 'RedHat',
+        :sshrsakey => 'AAAAB3NzaC1yc2EAAAABIwAAAQEArGElx46pD6NNnlxVaTbp0ZJMgBKCmbTCT3RaeCk0ZUJtQ8wkcwTtqIXmmiuFsynUT0DFSd8UIodnBOPqitimmooAVAiAi30TtJVzADfPScMiUnBJKZajIBkEMkwUcqsfh630jyBvLPE/kyQcxbEeGtbu1DG3monkeymanOBW1AKc5o+cJLXcInLnbowMG7NXzujT3BRYn/9s5vtT1V9cuZJs4XLRXQ50NluxJI7sVfRPVvQI9EMbTS4AFBXUej3yfgaLSV+nPZC/lmJ2gR4t/tKvMFF9m16f8IcZKK7o0rK7v81G/tREbOT5YhcKLK+0wBfR6RsmHzwy4EddZloyLQ=='
+      }
+    end
+    let :params do
+      { :sshd_client_alive_count_max => 'invalid' }
+    end
+
+    it 'should fail' do
+      expect {
+        should contain_class('ssh')
+      }.to raise_error(Puppet::Error,/^ssh::sshd_client_alive_count_max must be an integer and is set to <invalid>\./)
+    end
+  end
+
   context 'with sshd_config_banner set to invalid value on valid osfamily' do
     let(:params) { { :sshd_config_banner => 'invalid/path' } }
     let(:facts) do

templates/sshd_config.erb

@@ -130,7 +130,7 @@ PrintMotd <%= @sshd_config_print_motd %>
 #Compression delayed
 #ClientAliveInterval 0
 ClientAliveInterval <%= @sshd_client_alive_interval %>
-#ClientAliveCountMax 3
+ClientAliveCountMax <%= @sshd_client_alive_count_max %>
 #ShowPatchLevel no
 <% if @sshd_config_use_dns_real != nil -%>
 #UseDNS yes