ssh(sec): fix newline problem on key saving that would allow bypassing command sandbox.

rhodecode/apps/ssh_support/utils.py

@@ -1,125 +1,131 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2016-2018 RhodeCode GmbH
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License, version 3
 # (only), as published by the Free Software Foundation.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 # This program is dual-licensed. If you wish to learn more about the
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 import os
 import stat
 import logging
 import tempfile
 import datetime
 
 from . import config_keys
 from rhodecode.model.db import true, joinedload, User, UserSshKeys
 
 
 log = logging.getLogger(__name__)
 
 HEADER = \
     "# This file is managed by RhodeCode, please do not edit it manually. # \n" \
     "# Current entries: {}, create date: UTC:{}.\n"
 
 # Default SSH options for authorized_keys file, can be override via .ini
 SSH_OPTS = 'no-pty,no-port-forwarding,no-X11-forwarding,no-agent-forwarding'
 
 
 def get_all_active_keys():
     result = UserSshKeys.query() \
         .options(joinedload(UserSshKeys.user)) \
         .filter(UserSshKeys.user != User.get_default_user()) \
         .filter(User.active == true()) \
         .all()
     return result
 
 
 def _generate_ssh_authorized_keys_file(
         authorized_keys_file_path, ssh_wrapper_cmd, allow_shell, ssh_opts, debug):
 
     authorized_keys_file_path = os.path.abspath(
         os.path.expanduser(authorized_keys_file_path))
 
     import rhodecode
     all_active_keys = get_all_active_keys()
 
     if allow_shell:
         ssh_wrapper_cmd = ssh_wrapper_cmd + ' --shell'
     if debug:
         ssh_wrapper_cmd = ssh_wrapper_cmd + ' --debug'
 
     if not os.path.isfile(authorized_keys_file_path):
         log.debug('Creating file at %s', authorized_keys_file_path)
         with open(authorized_keys_file_path, 'w'):
             pass
 
     if not os.access(authorized_keys_file_path, os.R_OK):
         raise OSError('Access to file {} is without read access'.format(
             authorized_keys_file_path))
 
     line_tmpl = '{ssh_opts},command="{wrapper_command} {ini_path} --user-id={user_id} --user={user} --key-id={user_key_id}" {key}\n'
 
     fd, tmp_authorized_keys = tempfile.mkstemp(
         '.authorized_keys_write',
         dir=os.path.dirname(authorized_keys_file_path))
 
     now = datetime.datetime.utcnow().isoformat()
     keys_file = os.fdopen(fd, 'wb')
     keys_file.write(HEADER.format(len(all_active_keys), now))
     ini_path = rhodecode.CONFIG['__file__']
 
     for user_key in all_active_keys:
         username = user_key.user.username
         user_id = user_key.user.user_id
+        # replace all newline from ends and inside
+        safe_key_data = user_key.ssh_key_data\
+            .strip()\
+            .replace('\n', ' ')\
+            .replace('\r', ' ')
 
-        keys_file.write(
-            line_tmpl.format(
+        line = line_tmpl.format(
                 ssh_opts=ssh_opts or SSH_OPTS,
                 wrapper_command=ssh_wrapper_cmd,
                 ini_path=ini_path,
                 user_id=user_id,
                 user=username,
                 user_key_id=user_key.ssh_key_id,
-                key=user_key.ssh_key_data))
+            key=safe_key_data)
+
+        keys_file.write(line)
         log.debug('addkey: Key added for user: `%s`', username)
     keys_file.close()
 
     # Explicitly setting read-only permissions to authorized_keys
     os.chmod(tmp_authorized_keys, stat.S_IRUSR | stat.S_IWUSR)
     # Rename is atomic operation
     os.rename(tmp_authorized_keys, authorized_keys_file_path)
 
 
 def generate_ssh_authorized_keys_file(registry):
     log.info('Generating new authorized key file')
 
     authorized_keys_file_path = registry.settings.get(
         config_keys.authorized_keys_file_path)
 
     ssh_wrapper_cmd = registry.settings.get(
         config_keys.wrapper_cmd)
     allow_shell = registry.settings.get(
         config_keys.wrapper_allow_shell)
     ssh_opts = registry.settings.get(
         config_keys.authorized_keys_line_ssh_opts)
     debug = registry.settings.get(
         config_keys.enable_debug_logging)
 
     _generate_ssh_authorized_keys_file(
         authorized_keys_file_path, ssh_wrapper_cmd, allow_shell, ssh_opts,
         debug)
 
     return 0

rhodecode/templates/admin/users/user_edit_ssh_keys_generate.mako

@@ -1,51 +1,51 b''
 <div class="panel panel-default">
     <div class="panel-heading">
       <h3 class="panel-title">${_('New SSH Key generated')}</h3>
     </div>
     <div class="panel-body">
         <p>
             ${_('Below is a 2048 bit generated SSH RSA key. You can use it to access RhodeCode via the SSH wrapper.')}
         </p>
         <h4>${_('Private key')}</h4>
         <pre>
-# Save the content as
-# Windows: /Users/<username>/.ssh/id_rsa_rhodecode_access_priv.key
-# macOS: /Users/<yourname>/.ssh/id_rsa_rhodecode_access_priv.key
-# Linux: /home/<username>/.ssh/id_rsa_rhodecode_access_priv.key
+# Save the below content as
+# Windows: /Users/{username}/.ssh/id_rsa_rhodecode_access_priv.key
+# macOS: /Users/{yourname}/.ssh/id_rsa_rhodecode_access_priv.key
+# Linux: /home/{username}/.ssh/id_rsa_rhodecode_access_priv.key
 
 # Change permissions to 0600 to make it secure, and usable.
-e.g chmod 0600 /home/<username>/.ssh/id_rsa_rhodecode_access_priv.key
+e.g chmod 0600 /home/{username}/.ssh/id_rsa_rhodecode_access_priv.key
         </pre>
 
         <div>
             <textarea style="height: 300px">${c.private}</textarea>
         </div>
         <br/>
 
         <h4>${_('Public key')}</h4>
         <pre>
-# Save the content as
-# Windows: /Users/<username>/.ssh/id_rsa_rhodecode_access_pub.key
-# macOS: /Users/<yourname>/.ssh/id_rsa_rhodecode_access_pub.key
-# Linux: /home/<username>/.ssh/id_rsa_rhodecode_access_pub.key
+# Save the below content as
+# Windows: /Users/{username}/.ssh/id_rsa_rhodecode_access_pub.key
+# macOS: /Users/{yourname}/.ssh/id_rsa_rhodecode_access_pub.key
+# Linux: /home/{username}/.ssh/id_rsa_rhodecode_access_pub.key
         </pre>
 
         <input type="text" value="${c.public}" class="large text" size="100"/>
         <p>
             % if hasattr(c, 'target_form_url'):
                 <a href="${c.target_form_url}">${_('Use this generated key')}.</a>
             % else:
                 <a href="${h.route_path('edit_user_ssh_keys', user_id=c.user.user_id, _query=dict(default_key=c.public))}">${_('Use this generated key')}.</a>
             % endif
             ${_('Confirmation required on the next screen')}.
         </p>
     </div>
 </div>
 
 <script>
 
 $(document).ready(function(){
 
 
 });
 </script>