"""
Common functions for processing OVAL in SSG
"""
from __future__ import absolute_import
from __future__ import print_function
import sys
import os
from .constants import oval_footer as footer
from .constants import oval_namespace as ovalns
from .xml import ElementTree as ET
from .xml import oval_generated_header
from .jinja import process_file_with_macros
from .products import _get_implied_properties
ASSUMED_OVAL_VERSION_STRING = "5.11"
# globals, to make recursion easier in case we encounter extend_definition
try:
ET.register_namespace("oval", ovalns)
except AttributeError:
# Legacy Python 2.6 fix, see e.g.
# https://www.programcreek.com/python/example/57552/xml.etree.ElementTree._namespace_map
from xml.etree import ElementTree as ET
ET._namespace_map[ovalns] = "oval"
def applicable_platforms(oval_file, oval_version_string=None):
"""
Returns the applicable platforms for a given OVAL file.
This function processes an OVAL file to extract the platforms it applies to. It uses a
specified OVAL version string or a default version if none is provided. The function
constructs an XML tree from the OVAL file and extracts platform information from it.
Args:
oval_file (str): The path to the OVAL file to be processed.
oval_version_string (str, optional): The OVAL version string to be used.
If not provided, a default version is used.
Returns:
list: A list of platforms that the OVAL file applies to.
Raises:
Exception: If there is an error while parsing the OVAL file.
"""
platforms = []
if not oval_version_string:
oval_version_string = ASSUMED_OVAL_VERSION_STRING
header = oval_generated_header("applicable_platforms", oval_version_string, "0.0.1")
oval_version_list = [int(num) for num in oval_version_string.split(".")]
subst_dict = dict(target_oval_version=oval_version_list)
oval_filename_components = oval_file.split(os.path.sep)
if len(oval_filename_components) > 3:
subst_dict["rule_id"] = oval_filename_components[-3]
else:
msg = "Unable to get rule ID from OVAL path '{path}'".format(path=oval_file)
print(msg, file=sys.stderr)
subst_dict = _get_implied_properties(subst_dict)
subst_dict['target_oval_version'] = [999, 999.999]
body = process_file_with_macros(oval_file, subst_dict)
try:
oval_tree = ET.fromstring(header + body + footer)
except Exception as e:
msg = "Error while loading " + oval_file
print(msg, file=sys.stderr)
raise e
element_path = "./{%s}def-group/{%s}definition/{%s}metadata/{%s}affected/{%s}platform"
element_ns_path = element_path % (ovalns, ovalns, ovalns, ovalns, ovalns)
for node in oval_tree.findall(element_ns_path):
platforms.append(node.text)
return platforms
def parse_affected(oval_contents):
"""
Returns the tuple (start_affected, end_affected, platform_indents) for the passed OVAL file contents.
Args:
oval_contents (list of str): The contents of the OVAL file, where each element is a line from
the file.
Returns:
tuple: A tuple containing:
- start_affected (int): The line number of the starting <affected> tag.
- end_affected (int): The line number of the closing </affected> tag.
- platform_indents (str): The indenting characters before the contents of the
<affected> element.
Raises:
ValueError: If the OVAL file does not contain a single <affected> element, if the start
tag is after the end tag, or if the tags contain other elements.
"""
start_affected = list(filter(lambda x: "<affected" in oval_contents[x],
range(0, len(oval_contents))))
if len(start_affected) != 1:
raise ValueError("OVAL file does not contain a single <affected> "
"element; counted %d in:\n%s\n\n" %
(len(start_affected), "\n".join(oval_contents)))
start_affected = start_affected[0]
end_affected = list(filter(lambda x: "</affected" in oval_contents[x],
range(0, len(oval_contents))))
if len(end_affected) != 1:
raise ValueError("Malformed OVAL file does not contain a single "
"closing </affected>; counted %d in:\n%s\n\n" %
(len(start_affected), "\n".join(oval_contents)))
end_affected = end_affected[0]
if start_affected >= end_affected:
raise ValueError("Malformed OVAL file: start affected tag begins "
"on the same line or after ending affected tag: "
"start:%d vs end:%d:\n%s\n\n" %
(start_affected, end_affected, oval_contents))
# Validate that start_affected contains only a starting <affected> tag;
# otherwise, using this information to update the <platform> subelements
# would fail.
start_line = oval_contents[start_affected]
start_line = start_line.strip()
if not start_line.startswith('<affected'):
raise ValueError("Malformed OVAL file: line with starting affected "
"tag contains other elements: line:%s\n%s\n\n" %
(start_line, oval_contents))
if '<' in start_line[1:]:
raise ValueError("Malformed OVAL file: line with starting affected "
"tag contains other elements: line:%s\n%s\n\n" %
(start_line, oval_contents))
# Validate that end_affected contains only an ending </affected> tag;
# otherwise, using this information to update the <platform> subelements
# would fail.
end_line = oval_contents[end_affected]
end_line = end_line.strip()
if not end_line.startswith('</affected>'):
raise ValueError("Malformed OVAL file: line with ending affected "
"tag contains other elements: line:%s\n%s\n\n" %
(end_line, oval_contents))
if '<' in end_line[1:]:
raise ValueError("Malformed OVAL file: line with ending affected "
"tag contains other elements: line:%s\n%s\n\n" %
(end_line, oval_contents))
indents = ""
if start_affected+1 == end_affected:
# Since the affected element is present but empty, the indents should
# be two more spaces than that of the starting <affected> element.
start_index = oval_contents[start_affected].index('<')
indents = oval_contents[start_affected][0:start_index]
indents += " "
else:
# Otherwise, grab the indents off the next line unmodified, as this is
# likely a platform element tag. We don't validate here that this is
# indeed the case, as other parts of the build infrastructure will
# validate this for us.
start_index = oval_contents[start_affected+1].index('<')
indents = oval_contents[start_affected+1][0:start_index]
return start_affected, end_affected, indents