Synnefo

#

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import base64

import binascii

import re

from hashlib import md5

from django.db import models

from django.conf import settings

from django.core.exceptions import ValidationError, NON_FIELD_ERRORS

from django.core.validators import MaxLengthValidator

from django.db.models.signals import pre_save

try:

    from paramiko import rsakey, dsskey, SSHException

except:

    pass

SSH_KEY_MAX_CONTENT_LENGTH = getattr(settings,

                                     'USERDATA_SSH_KEY_MAX_CONTENT_LENGTH',

                                     30000)

class ProfileModel(models.Model):

    """

    Abstract model, provides a basic interface for models that store

    user specific information

    """

    user = models.CharField(max_length=100)

    class Meta:

        abstract = True

        app_label = 'userdata'

class PublicKeyPair(ProfileModel):

    """

    Public key model

    """

    name = models.CharField(max_length=255, null=False, blank=False)

    content = models.TextField(validators=[

        MaxLengthValidator(SSH_KEY_MAX_CONTENT_LENGTH)])

    fingerprint = models.CharField(max_length=100, null=False, blank=True)

    class Meta:

        app_label = 'userdata'

    def full_clean(self, *args, **kwargs):

        # update fingerprint before clean

        self.update_fingerprint()

        super(PublicKeyPair, self).full_clean(*args, **kwargs)

    def key_data(self):

        return self.content.split(" ", 1)

    def get_key_object(self):

        """

        Identify key contents and return appropriate paramiko public key object

        """

        key_type, data = self.key_data()

        data = base64.b64decode(data)

        if key_type == "ssh-rsa":

            key = rsakey.RSAKey(data=data)

        elif key_type == "ssh-dss":

            key = dsskey.DSSKey(data=data)

        else:

            raise Exception("Invalid key type")

        return key

    def clean_key(self):

        key = None

        try:

            key = self.get_key_object()

        except:

            raise ValidationError("Invalid SSH key")

    def clean(self):

        if PublicKeyPair.user_limit_exceeded(self.user):

            raise ValidationError("SSH keys limit exceeded.")

    def update_fingerprint(self):

        try:

            fp = binascii.hexlify(self.get_key_object().get_fingerprint())

            self.fingerprint = ":".join(re.findall(r"..", fp))

        except:

            self.fingerprint = "unknown fingerprint"

    def save(self, *args, **kwargs):

        self.update_fingerprint()

        super(PublicKeyPair, self).save(*args, **kwargs)

    @classmethod

    def user_limit_exceeded(cls, user):

        return (PublicKeyPair.objects.filter(user=user).count() >=

                settings.USERDATA_MAX_SSH_KEYS_PER_USER)