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systemsmanagement:Uyuni:Snapshots:2021.09
cobbler
v3-1-2-arbitrary-file-read-write-plus-RCE.patch
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File v3-1-2-arbitrary-file-read-write-plus-RCE.patch of Package cobbler
From 97116e47ebe065fa8641bc79d1527bf13b3cf196 Mon Sep 17 00:00:00 2001 From: SchoolGuy <egotthold@suse.de> Date: Thu, 26 Aug 2021 12:50:09 +0200 Subject: [PATCH] Backport of the arbitrary file read & write plus RCE --- cobbler/remote.py | 94 ++++++++++++++++++++++++++++++++++----------- cobbler/tftpgen.py | 18 ++++++--- cobbler/validate.py | 45 +++++++++++++++++++++- 3 files changed, 127 insertions(+), 30 deletions(-) diff --git a/cobbler/remote.py b/cobbler/remote.py index 0cc2ad7a..44376260 100644 --- a/cobbler/remote.py +++ b/cobbler/remote.py @@ -28,6 +28,7 @@ from past.utils import old_div import base64 import errno import fcntl +import keyword import os import random import xmlrpc.server @@ -43,6 +44,7 @@ from cobbler.items import package, system, image, profile, repo, mgmtclass, dist from cobbler import tftpgen from cobbler import utils from cobbler.cexceptions import CX +from cobbler.validate import validate_autoinstall_script_name, validate_obj_id, validate_obj_name EVENT_TIMEOUT = 7 * 24 * 60 * 60 # 1 week @@ -546,12 +548,14 @@ class CobblerXMLRPCInterface(object): :return: The username if the token was valid. :raises CX: If the token supplied to the function is invalid. """ + if not CobblerXMLRPCInterface.__is_token(token): + raise ValueError("\"token\" did not have the correct format or type!") if token not in self.token_cache: raise CX("invalid token: %s" % token) else: return self.token_cache[token][1] - def _log(self, msg, user=None, token=None, name=None, object_id=None, attribute=None, debug=False, error=False): + def _log(self, msg, token=None, name=None, object_id=None, attribute=None, debug=False, error=False): """ Helper function to write data to the log file from the XMLRPC remote implementation. Takes various optional parameters that should be supplied when known. @@ -567,10 +571,10 @@ class CobblerXMLRPCInterface(object): :param error: If the message logged is an error message. :type error: bool """ + if not (isinstance(error, bool) or isinstance(debug, bool) or isinstance(msg, str)): + return # add the user editing the object, if supplied m_user = "?" - if user is not None: - m_user = user if token is not None: try: m_user = self.get_user_from_token(token) @@ -580,13 +584,21 @@ class CobblerXMLRPCInterface(object): msg = "REMOTE %s; user(%s)" % (msg, m_user) if name is not None: + if not isinstance(name, str): + return + if not validate_obj_name(name): + return msg = "%s; name(%s)" % (msg, name) if object_id is not None: + if not validate_obj_id(object_id): + return msg = "%s; object_id(%s)" % (msg, object_id) # add any attributes being modified, if any if attribute: + if not (isinstance(attribute, str) and attribute.isidentifier()) or keyword.iskeyword(attribute): + return msg = "%s; attribute(%s)" % (msg, attribute) # log to the correct logger @@ -1757,6 +1769,9 @@ class CobblerXMLRPCInterface(object): :param token: The API-token obtained via the login() method. :return: 0 on success, 1 on error. """ + if not self.api.settings().allow_dynamic_settings: + self._log("modify_setting - feature turned off but was tried to be accessed", token=token) + return 1 self._log("modify_setting(%s)" % setting_name, token=token) self.check_access(token, "modify_setting") try: @@ -2122,6 +2137,10 @@ class CobblerXMLRPCInterface(object): :return: Some generated script. """ self._log("generate_script, name is %s" % str(name)) + # This is duplicated from tftpgen.py to prevent log poisoning via a template engine (Cheetah, Jinja2). + if not validate_autoinstall_script_name(name): + raise ValueError("\"name\" handed to generate_script was not valid!") + self._log("generate_script, name is \"%s\"" % name) return self.api.generate_script(profile, system, name) def get_blended_data(self, profile=None, system=None): @@ -2407,6 +2426,8 @@ class CobblerXMLRPCInterface(object): :param rest: This is dropped in this method since it is not needed here. :return: True if everything succeeded. """ + if not self.__validate_log_data_params(sys_name, file, size, offset, data, token): + return False self._log("upload_log_data (file: '%s', size: %s, offset: %s)" % (file, size, offset), token=token, name=sys_name) # Check if enabled in self.api.settings() @@ -2415,15 +2436,36 @@ class CobblerXMLRPCInterface(object): return False # Find matching system record - systems = self.api.systems() - obj = systems.find(name=sys_name) + obj = self.api.find_system(name=sys_name) if obj is None: # system not found! - self._log("upload_log_data - WARNING - system '%s' not found in Cobbler" % sys_name, token=token, name=sys_name) + self._log("upload_log_data - WARNING - system '%s' not found in Cobbler" % sys_name, token=token, + name=sys_name) + return False - return self.__upload_file(sys_name, file, size, offset, data) + return self.__upload_file(obj.name, file, size, offset, data) + + def __validate_log_data_params(self, sys_name: str, logfile_name: str, size: int, offset: int, data: bytes, + token=None) -> bool: + # Validate all types + if not (isinstance(sys_name, str) and isinstance(logfile_name, str) and isinstance(size, int) + and isinstance(offset, int) and isinstance(data, bytes)): + self.logger.warning("upload_log_data - One of the parameters handed over had an invalid type!") + return False + if token is not None and not isinstance(token, str): + self.logger.warning("upload_log_data - token was given but had an invalid type.") + return False + # Validate sys_name with item regex + if not validate_obj_name(sys_name): + self.logger.warning("upload_log_data - The provided sys_name contained invalid characters!") + return False + # Validate logfile_name - this uses the script name validation, possibly we need our own for this one later + if not validate_autoinstall_script_name(logfile_name): + self.logger.warning("upload_log_data - The provided file contained invalid characters!") + return False + return True - def __upload_file(self, sys_name, file, size, offset, data): + def __upload_file(self, sys_name: str, logfile_name: str, size: int, offset: int, data: bytes) -> bool: """ Files can be uploaded in chunks, if so the size describes the chunk rather than the whole file. The offset indicates where the chunk belongs the special offset -1 is used to indicate the final chunk. @@ -2435,28 +2477,30 @@ class CobblerXMLRPCInterface(object): :param data: base64 encoded file contents :return: True if the action succeeded. """ - contents = base64.decodestring(data) + contents = base64.decodebytes(data) del data if offset != -1: if size is not None: if size != len(contents): return False - # XXX - have an incoming dir and move after upload complete - # SECURITY - ensure path remains under uploadpath - tt = str.maketrans("/", "+") - fn = str.translate(file, tt) - if fn.startswith('..'): - raise CX("invalid filename used: %s" % fn) + # FIXME: Get the base directory from Cobbler app-settings + anamon_base_directory = "/var/log/cobbler/anamon" + anamon_sys_directory = os.path.join(anamon_base_directory, sys_name) - # FIXME ... get the base dir from cobbler settings() - udir = "/var/log/cobbler/anamon/%s" % sys_name - if not os.path.isdir(udir): - os.mkdir(udir, 0o755) + file_name = os.path.join(anamon_sys_directory, logfile_name) + normalized_path = os.path.normpath(file_name) + + if not normalized_path.startswith(anamon_sys_directory): + self.logger.warning("upload_log_data: built path for the logfile was outside of the Cobbler-Anamon log " + "directory!") + return False + + if not os.path.isdir(anamon_sys_directory): + os.mkdir(anamon_sys_directory, 0o755) - fn = "%s/%s" % (udir, fn) try: - st = os.lstat(fn) + st = os.lstat(file_name) except OSError as e: if e.errno == errno.ENOENT: pass @@ -2464,9 +2508,9 @@ class CobblerXMLRPCInterface(object): raise else: if not stat.S_ISREG(st.st_mode): - raise CX("destination not a file: %s" % fn) + raise CX("destination not a file: %s" % file_name) - fd = os.open(fn, os.O_RDWR | os.O_CREAT, 0o644) + fd = os.open(file_name, os.O_RDWR | os.O_CREAT | os.O_CLOEXEC, 0o644) # log_error("fd=%r" %fd) try: if offset == 0 or (offset == -1 and size == len(contents)): @@ -3076,6 +3120,10 @@ class CobblerXMLRPCInterface(object): self.token_cache[b64] = (time.time(), user) return b64 + @staticmethod + def __is_token(token: str) -> bool: + return isinstance(token, str) and len(token) == 36 + def __invalidate_expired_tokens(self): """ Deletes any login tokens that might have expired. Also removes expired events. diff --git a/cobbler/tftpgen.py b/cobbler/tftpgen.py index 54a4f731..d95bf001 100644 --- a/cobbler/tftpgen.py +++ b/cobbler/tftpgen.py @@ -29,6 +29,7 @@ import socket from cobbler import templar from cobbler import utils from cobbler.cexceptions import CX +from cobbler.validate import validate_autoinstall_script_name class TFTPGen(object): @@ -1072,8 +1073,13 @@ class TFTPGen(object): """ if what == "profile": obj = self.api.find_profile(name=objname) - else: + elif what == "system": obj = self.api.find_system(name=objname) + else: + raise ValueError("\"what\" needs to be either \"profile\" or \"system\"!") + + if not validate_autoinstall_script_name(script_name): + raise ValueError("\"script_name\" handed to generate_script was not valid!") if not obj: return "# %s named %s not found" % (what, objname) @@ -1098,12 +1104,14 @@ class TFTPGen(object): else: blended['img_path'] = os.path.join("/images", distro.name) - template = os.path.normpath(os.path.join("/var/lib/cobbler/autoinstall_scripts", script_name)) + scripts_root = "/var/lib/cobbler/scripts" + template = os.path.normpath(os.path.join(scripts_root, script_name)) + if not template.startswith(scripts_root): + return "# script template \"%s\" could not be found in the script root" % script_name if not os.path.exists(template): return "# script template %s not found" % script_name - template_fh = open(template) - template_data = template_fh.read() - template_fh.close() + with open(template) as template_fh: + template_data = template_fh.read() return self.templar.render(template_data, blended, None, obj) diff --git a/cobbler/validate.py b/cobbler/validate.py index f527efe8..3a6c758e 100644 --- a/cobbler/validate.py +++ b/cobbler/validate.py @@ -20,10 +20,13 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA import netaddr import re import shlex +from uuid import UUID -from cobbler.cexceptions import CX +import netaddr +from cobbler.cexceptions import CX +RE_SCRIPT_NAME = re.compile(r"[a-zA-Z0-9_.]+") RE_OBJECT_NAME = re.compile(r'[a-zA-Z0-9_\-.:]*$') RE_HOSTNAME = re.compile(r'^([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])(\.([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]{0,61}[a-zA-Z0-9]))*$') @@ -249,4 +252,42 @@ def name_servers_search(search, for_item=True): return search -# EOF + +def validate_autoinstall_script_name(name: str) -> bool: + if not isinstance(name, str): + return False + if re.fullmatch(RE_SCRIPT_NAME, name): + return True + return False + + +def validate_uuid(possible_uuid: str) -> bool: + if not isinstance(possible_uuid, str): + return False + # Taken from: https://stackoverflow.com/a/33245493/4730773 + try: + uuid_obj = UUID(possible_uuid, version=4) + except ValueError: + return False + return str(uuid_obj) == possible_uuid + + +def validate_obj_type(object_type: str) -> bool: + if not isinstance(object_type, str): + return False + return object_type in ["distro", "profile", "system", "repo", "image", "mgmtclass", "package", "file", "menu"] + + +def validate_obj_name(future_object_name: str) -> bool: + if not isinstance(future_object_name, str): + return False + return bool(re.fullmatch(RE_OBJECT_NAME, future_object_name)) + + +def validate_obj_id(object_id: str) -> bool: + if not isinstance(object_id, str): + return False + if object_id.startswith("___NEW___"): + object_id = object_id[9:] + (otype, oname) = object_id.split("::", 1) + return validate_obj_type(otype) and validate_obj_name(oname) -- 2.32.0
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