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adding support to kerberos authentication
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ltamaster committed Jun 10, 2019
1 parent 5e78db3 commit 460c261
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89 changes: 64 additions & 25 deletions README.md
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Expand Up @@ -8,29 +8,7 @@ Download from the releases page and copy the py-winrm-plugin-X.X.X.zip to the li

## Requierments

The plugin needs the python module pywinrm. It can be installed with the following command: ```pip install pywinrm```

Additional, it could be added the support for kerberos and credSSP autentication:

### To use Kerberos authentication you need these optional dependencies
#### for Debian/Ubuntu/etc:

```
$ sudo apt-get install python-dev libkrb5-dev
$ pip install pywinrm[kerberos]
```

#### for RHEL/CentOS/etc:
```
$ sudo yum install gcc krb5-devel krb5-workstation
$ pip install pywinrm[kerberos]
```

### To use CredSSP authentication you need these optional dependencies
```
pip install pywinrm[credssp]
```

The plugin needs the python module **pywinrm**. It can be installed with the following command: ```pip install pywinrm```

For further information see:
[https://pypi.python.org/pypi/pywinrm
Expand All @@ -39,7 +17,7 @@ For further information see:

## Configuration

* **Authentication Type**: The authentication type used for the connection: basic, ntlm, credssp. It can be overwriting at node level using `winrm-authtype`
* **Authentication Type**: The authentication type used for the connection: basic, ntlm, credssp, kerberos. It can be overwriting at node level using `winrm-authtype`
* **Username**: (Optional) Username that will connect to the remote node. This value can be set also at node level or as a job input option (with the name `username)
* **Password Storage Path**: Key storage path of the window's user password. It can be overwriting at node level using `winrm-password-storage-path`.
Also the password can be overwritten on the job level using an input secure option called `winrmpassword`
Expand All @@ -48,6 +26,10 @@ For further information see:
* **WinRM Port**: WinRM port (Default: 5985/5986 for http/https). It can be overwriting at node level using `winrm-port`
* **Shell**: Windows Shell interpreter (powershell o cmd). It can be overwriting at node level using `winrm-shell`

For Kerberos
* **krb5 Config File**: path of the krb5.conf (default: /etc/krb5.conf)
* **Kinit Command**: `kinit` command used for create ticket (default: kinit)

## Node definition example


Expand All @@ -63,11 +45,68 @@ For further information see:
osVersion="6.3"
username="rundeckuser@domain.local"
winrm-password-storage-path="keys/node/windows.password"
winrm-authtype="credssp"/>
winrm-authtype="basic"/>
```

The username can be overwritten using a job input option called "username"` or it can be set at project level.

## Transport methods
The transport methods supported are:

* basic
* kerberos
* ntlm
* credssp

Further information [here](https://github.com/diyan/pywinrm#valid-transport-options)


### CredSSP

To use CredSSP authentication you need these optional dependencies
```
pip install pywinrm[credssp]
```

## Kerberos

The pywinrm library has support for kerberos authentication, but it cannot create the kerberos ticket, which needs to be initiate outside the pywinrm scope:

```
kerberos: Will use Kerberos authentication for domain accounts which only works when the client is in the same domain as the server and the required dependencies are installed. Currently a Kerberos ticket needs to be initialized outside of pywinrm using the kinit command.
```
Source [here](https://github.com/diyan/pywinrm#valid-transport-options)


So, in order to connect to a windows box using kerberos we added a call to the `kinit username` command before connecting to the node.

In resume, to use Kerberos authentication the following requirements are needed:

* domain accounts which only works when the client is in the same domain as the server
* kerberos client installed
* domain set on krb5.conf file (default /etc/krb5.conf)
* python `pexpect` library
* python `kerberos` library
* Kerberos authentication enabled on remote windows node (WINRM settings)

### Install Basic dependencies
#### for Debian/Ubuntu/etc:

```
$ sudo apt-get install python-dev libkrb5-dev
$ pip install pywinrm[kerberos]
$ pip install pexpect
```

#### for RHEL/CentOS/etc:
```
$ sudo yum install gcc krb5-devel krb5-workstation
$ pip install pywinrm[kerberos]
$ pip install pexpect
```


## Limitations

Don't use the file copier to transfer big files, the performance is not the best to transfer large files. It works OK passing inline scripts to remote windows nodes
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106 changes: 106 additions & 0 deletions contents/kerberosauth.py
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@@ -0,0 +1,106 @@
import os
import json

try:
import pexpect
except ImportError as e:
pass


class KerberosAuth(object):
def __init__(self, krb5config, kinit_command, log, username, password):
self.krb5config = krb5config
self.kinit_command = kinit_command
self.log = log
self.username = username
self.password = password



def get_ticket(self):
kinit = [self.kinit_command]

kinit_arg = []
kinit_arg.append("-f")
kinit_arg.append("-V")
kinit_arg.append(self.username)

self.log.debug("running kinit %s" %kinit)

krb5env=()
if(self.krb5config):
os.environ["KRB5_CONFIG"]=self.krb5config
krb5env = dict(KRB5_CONFIG=self.krb5config)

try:
process = pexpect.spawn(kinit.pop(0), kinit_arg, timeout=60, env=krb5env)
except pexpect.ExceptionPexpect as err:
msg = "Error creating kerberos ticket %s" % err
self.log.error(msg)
raise Exception(msg)

process.expect(".*:")
process.sendline(self.password)

output = process.read()
process.wait()
self.log.debug("Exist status: %s" %process.exitstatus)
self.log.debug("kinit finish with message %s" %output)

exitCode = process.exitstatus

if exitCode != 0:
msg = "kinit failed %s" % output
self.log.error(msg)
raise Exception(msg)

self.log.debug("kinit succeeded for %s" % self.username)


#just for macos (skipped by the moment)
def check_ticket(self):
try:

klist_command = ["klist"]
kinit_arg = []
kinit_arg.append("--list-all")
kinit_arg.append("--json")
self.log.debug("running klist %s %s" % (klist_command,kinit_arg))

krb5env = ()
if (self.krb5config):
os.environ["KRB5_CONFIG"] = self.krb5config
krb5env = dict(KRB5_CONFIG=self.krb5config)

try:
process = pexpect.spawn(klist_command.pop(0), kinit_arg, timeout=60,
env=krb5env, echo=False)
except pexpect.ExceptionPexpect as err:
msg = "Error checking klist %s" % err
self.log.error(msg)
return False

process.expect(".*")
output = process.read()
process.wait()
if process.exitstatus!=0:
return False

self.log.debug("klist result %s" % output)
results = json.loads(output)

for item in results:
ticket_name=item["Name"]
expired=item["Expired"]

if ticket_name.upper() == self.username.upper():
self.log.debug("Ticket found for user %s, expired: %s"%(ticket_name, expired))
if expired == "no":
self.log.debug("Ticket not expired, skipping kinit")

return True

return False
except Exception as e:
self.log.debug("error running klist command : %s" %e)
return False
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