x/cloudbase-init
Code Issues Proposed changes

Improve MIME multipart userdata handling

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The 'exec_file' will now try to check for the headers inside the file, in
case that it doesn't recognize the format or no format has been provided.
Also the processing part of the user data now checks if the 'Content-Type' is
in the file instead of checking if the file starts with the header, in
order to comply with RFC2045.

Change-Id: I53fda9f5c17f35cb35d93a86434ecc4c7c579802
Closes-Bug: #1623393
Closes-Bug: #1672222
This commit is contained in:
Stefan Caraiman
2016-09-21 09:47:33 +03:00
parent 122a5c58bc
commit 8e5fff7016
6 changed files with 113 additions and 74 deletions
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24
cloudbaseinit/plugins/common/fileexecutils.py
View File

@@ -12,35 +12,23 @@
# License for the specific language governing permissions and limitations
# under the License.
import os
from oslo_log import log as oslo_logging
from cloudbaseinit.plugins.common import execcmd
from cloudbaseinit.plugins.common import userdatautils
LOG = oslo_logging.getLogger(__name__)
FORMATS = {
"cmd": execcmd.Shell,
"exe": execcmd.Shell,
"sh": execcmd.Bash,
"py": execcmd.Python,
"ps1": execcmd.PowershellSysnative,
}
def exec_file(file_path):
ret_val = 0
ext = os.path.splitext(file_path)[1][1:].lower()
command = FORMATS.get(ext)
command = userdatautils.get_command_from_path(file_path)
if not command:
# Unsupported
LOG.warning('Unsupported script file type: %s', ext)
# File format not provided or not recognized
LOG.debug('No valid extension or header found in the '
'userdata: %s' % file_path)
return ret_val
try:
out, err, ret_val = command(file_path).execute()
out, err, ret_val = command.execute()
except Exception as ex:
LOG.warning('An error occurred during file execution: \'%s\'', ex)
else:

22
cloudbaseinit/plugins/common/userdata.py
View File

@@ -83,11 +83,29 @@ class UserDataPlugin(base.BasePlugin):
LOG.debug('User data content:\n%s', user_data_str)
return email.message_from_string(user_data_str).walk()
@staticmethod
def _get_headers(user_data):
"""Returns the header of the given user data.
:param user_data: Represents the content of the user data.
:rtype: A string chunk containing the header or None.
.. note :: In case the content type is not valid,
None will be returned.
"""
content = encoding.get_as_string(user_data)
if content:
return content.split("\n\n")[0]
else:
raise exception.CloudbaseInitException("No header could be found."
"The user data content is "
"either invalid or empty.")
def _process_user_data(self, user_data):
plugin_status = base.PLUGIN_EXECUTION_DONE
reboot = False
LOG.debug("Processing userdata")
if user_data.startswith(b'Content-Type: multipart'):
headers = self._get_headers(user_data)
if 'Content-Type: multipart' in headers:
LOG.debug("Processing userdata")
user_data_plugins = factory.load_plugins()
user_handlers = {}

74
cloudbaseinit/plugins/common/userdatautils.py
View File

@@ -12,8 +12,8 @@
# License for the specific language governing permissions and limitations
# under the License.
import functools
import collections
import os
import re
from oslo_log import log as oslo_logging
@@ -23,37 +23,69 @@ from cloudbaseinit.plugins.common import execcmd
LOG = oslo_logging.getLogger(__name__)
# Avoid 80+ length by using a local variable, which
# is deleted afterwards.
_compile = functools.partial(re.compile, flags=re.I)
FORMATS = (
(_compile(br'^rem\s+cmd\s'), execcmd.Shell),
(_compile(br'^#!\s*/usr/bin/env\s+python\s'), execcmd.Python),
(_compile(br'^#!'), execcmd.Bash),
(_compile(br'^#(ps1|ps1_sysnative)\s'), execcmd.PowershellSysnative),
(_compile(br'^#ps1_x86\s'), execcmd.Powershell),
(_compile(br'</?(script|powershell)>'), execcmd.EC2Config),
)
del _compile
_Script = collections.namedtuple('Script', ['extension', 'script_type',
'executor'])
_SCRIPTS = (
_Script(extension='cmd', executor=execcmd.Shell,
script_type=re.compile(br'^rem\s+cmd\s')),
_Script(script_type=re.compile(br'^#!\s*/usr/bin/env\s+python\s'),
extension='py', executor=execcmd.Python),
_Script(extension='exe', script_type=None, executor=execcmd.Shell),
_Script(extension='sh', script_type=re.compile(br'^#!'),
executor=execcmd.Bash),
_Script(extension='ps1', executor=execcmd.PowershellSysnative,
script_type=re.compile(br'^#(ps1|ps1_sysnative)\s')),
_Script(extension=None, executor=execcmd.Powershell,
script_type=re.compile(br'^#ps1_x86\s')),
_Script(extension=None, executor=execcmd.EC2Config,
script_type=re.compile(br'</?(script|powershell)>')))
def _get_command(data):
# Get the command which should process the given data.
for pattern, command_class in FORMATS:
if pattern.search(data):
return command_class.from_data(data)
def _get_command(data, is_path=False):
"""Returns a specific command executor if the data type is found.
:param data: It can be either a file or content of user_data type.
:param is_path: Determines whether :data: is a file path or it
contains the user_data content.
:rtype: An `execcmd` command type or `None`.
.. note :: In case the data doesn't have a valid extension or
header, it will return `None`.
"""
if is_path:
extension = os.path.splitext(data)[1][1:].lower()
for script in _SCRIPTS:
if extension == script.extension:
return script.executor(data)
with open(data, 'rb') as file_handler:
file_handler.seek(0)
user_data = file_handler.read()
else:
user_data = data
for script in _SCRIPTS:
if script.script_type and script.script_type.search(user_data):
return script.executor.from_data(user_data)
return None
def get_command(data):
return _get_command(data)
def get_command_from_path(path):
return _get_command(path, is_path=True)
def execute_user_data_script(user_data):
ret_val = 0
out = err = None
command = _get_command(user_data)
command = get_command(user_data)
if not command:
LOG.warning('Unsupported user_data format')
return ret_val
try:
out, err, ret_val = command()
out, err, ret_val = command.execute()
except Exception as exc:
LOG.warning('An error occurred during user_data execution: \'%s\'',
exc)