File: build_sce.py

package info (click to toggle)
scap-security-guide 0.1.76-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 110,644 kB
  • sloc: xml: 241,883; sh: 73,777; python: 32,527; makefile: 27
file content (278 lines) | stat: -rw-r--r-- 10,640 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
from __future__ import absolute_import
from __future__ import print_function

import os
import os.path
import json

from .build_yaml import Rule, DocumentationNotComplete
from .constants import (
    MULTI_PLATFORM_LIST, OSCAP_VALUE, datastream_namespace,
    xlink_namespace, XCCDF12_NS, SCE_SYSTEM
)
from .jinja import process_file_with_macros
from .rules import get_rule_dir_id, get_rule_dir_sces, find_rule_dirs_in_paths
from . import utils, products


def write_sce_file(sce_content, output_dir, filename):
    with open(os.path.join(output_dir, filename), 'w') as output_file:
        print(sce_content, file=output_file)


def load_sce_and_metadata(file_path, local_env_yaml):
    """
    For the given SCE audit file (file_path) under the specified environment
    (local_env_yaml), parse the file while expanding Jinja macros and read any
    metadata headers the file contains. Note that the last keyword of a
    specified type is the recorded one.

    Returns (audit_content, metadata).
    """

    raw_content = process_file_with_macros(file_path, local_env_yaml)
    return load_sce_and_metadata_parsed(raw_content)


def _process_raw_content_line(line, sce_content, metadata):
    found_metadata = False
    keywords = ['platform', 'check-import', 'check-export', 'complex-check', 'environment']
    for keyword in keywords:
        if not line.startswith('# ' + keyword + ' = '):
            continue
        found_metadata = True
        # Strip off the initial comment marker
        _, value = line[2:].split('=', maxsplit=1)
        metadata[keyword] = value.strip()

    if not found_metadata:
        sce_content.append(line)


def _parse_metadata(raw_content):
    metadata = dict()
    sce_content = []
    shebang = "#!/usr/bin/bash"
    for line in raw_content.split("\n"):
        if line.startswith("#!"):
            shebang = line
            continue
        _process_raw_content_line(line, sce_content, metadata)
    return shebang, "\n".join(sce_content), metadata


def _set_metadata_default_values(metadata):
    if 'check-export' in metadata:
        # Special case for the variables exposed to the SCE script: prepend
        # the OSCAP_VALUE prefix to reference the variable
        new_variables = []
        for value in metadata['check-export'].split(','):
            k, v = value.split('=', maxsplit=1)
            new_variables.append(k+'='+OSCAP_VALUE+v)
        metadata['check-export'] = new_variables

    if 'platform' in metadata:
        metadata['platform'] = metadata['platform'].split(',')
    else:
        metadata['platform'] = ['multi_platform_all']

    if "environment" not in metadata:
        metadata["environment"] = "any"
    environment_options = ["normal", "bootc", "any"]
    if metadata["environment"] not in environment_options:
        raise RuntimeError(
            "Wrong value of the 'environment' headers: '%s'. It needs to be "
            "one of %s" % (
                metadata["environment"], ", ".join(environment_options))
        )


def _modify_sce_with_environment(sce_content, environment):
    if environment == "any":
        return sce_content
    if environment == "bootc":
        condition = "(rpm -q --quiet bootc && [ -e /run/.containerenv ])"
    if environment == "normal":
        condition = "! (rpm -q --quiet bootc && [ -e /run/.containerenv ])"
    lines = list(sce_content.split("\n"))
    for i in range(len(lines)):
        if len(lines[i]) > 0:
            lines[i] = (4 * " ") + lines[i]
    lines.insert(0, "if " + condition + " ; then")
    lines.append("else")
    lines.append("    echo \"The SCE check can't run in this environment.\"")
    lines.append("    exit \"$XCCDF_RESULT_ERROR\"")
    lines.append("fi")
    return "\n".join(lines)


def load_sce_and_metadata_parsed(raw_content):
    shebang, sce_content, metadata = _parse_metadata(raw_content)
    _set_metadata_default_values(metadata)
    sce_content = _modify_sce_with_environment(sce_content, metadata["environment"])
    sce_content = shebang + "\n" + sce_content
    return sce_content, metadata


def _check_is_loaded(already_loaded, filename):
    # Right now this check doesn't look at metadata or anything
    # else. Eventually we might add versions to the entry or
    # something.
    return filename in already_loaded


# Retrieve the SCE checks and return a list of path to each check script.
def collect_sce_checks(datastreamtree):
    checklists = datastreamtree.find(
        ".//{%s}checklists" % datastream_namespace)
    checklists_component_ref = checklists.find(
        "{%s}component-ref" % datastream_namespace)
    # The component ID is the component-ref href without leading '#'
    checklist_component_id = checklists_component_ref.get('{%s}href' % xlink_namespace)[1:]

    checks_xpath = str.format(
        ".//{{{ds_ns}}}component[@id='{cid}']/"
        "{{{xccdf_ns}}}Benchmark//"
        "{{{xccdf_ns}}}Rule//"
        "{{{xccdf_ns}}}check[@system='{sce_sys}']/"
        "{{{xccdf_ns}}}check-content-ref",
        ds_ns=datastream_namespace,
        xccdf_ns=XCCDF12_NS,
        cid=checklist_component_id,
        sce_sys=SCE_SYSTEM
    )

    checks = datastreamtree.findall(checks_xpath)
    # Extract the file paths of the SCE checks
    return [check.get('href') for check in checks]


class SCEBuilder():
    def __init__(self, env_yaml, product_yaml, template_builder, output_dir):
        self.env_yaml = env_yaml
        self.product_yaml = product_yaml
        self.template_builder = template_builder
        self.output_dir = output_dir
        self.already_loaded = dict()

    def _build_static_sce_check(self, rule_id, path, local_env_yaml):
        # To be compatible with later checks, use the rule_id (i.e., the
        # value of _dir) to recreate the expected filename if this OVAL
        # was in a rule directory. However, note that unlike
        # build_oval.checks(...), we have to get this script's extension
        # first.
        _, ext = os.path.splitext(path)
        filename = "{0}{1}".format(rule_id, ext)

        sce_content, metadata = load_sce_and_metadata(path, local_env_yaml)
        metadata['filename'] = filename
        product = utils.required_key(self.env_yaml, "product")

        if not utils.is_applicable_for_product(",".join(metadata["platform"]), product):
            return
        if _check_is_loaded(self.already_loaded, rule_id):
            return

        write_sce_file(sce_content, self.output_dir, filename)

        self.already_loaded[rule_id] = metadata

    def _get_rule_sce_lang(self, rule):
        langs = self.template_builder.get_resolved_langs_to_generate(rule)
        for lang in langs:
            if lang.name == 'sce-bash':
                return lang
        return None

    def _build_templated_sce_check(self, rule):
        if not rule.template:
            return
        sce_lang = self._get_rule_sce_lang(rule)
        if sce_lang is None:
            return

        # Here we know the specified rule has a template and this
        # template actually generates (bash) SCE content. We
        # prioritize bespoke SCE content over templated content,
        # however, while we add this to our metadata, we do not
        # bother (yet!) with generating the SCE content. This is done
        # at a later time by build-scripts/build_templated_content.py.
        if _check_is_loaded(self.already_loaded, rule.id_):
            return

        # While we don't _write_ it, we still need to parse SCE
        # metadata from the templated content. Render it internally.
        raw_sce_content = self.template_builder.get_lang_contents_for_templatable(
            rule, sce_lang
        )

        ext = '.sh'
        filename = rule.id_ + ext

        # Load metadata and infer correct file name.
        sce_content, metadata = load_sce_and_metadata_parsed(raw_sce_content)
        metadata['filename'] = filename

        # Skip the check if it isn't applicable for this product.
        product = utils.required_key(self.env_yaml, "product")
        if not utils.is_applicable_for_product(",".join(metadata["platform"]), product):
            return

        write_sce_file(sce_content, self.output_dir, filename)

        # Finally, include it in our loaded content
        self.already_loaded[rule.id_] = metadata

    def _build_rule(self, rule_dir_path):
        local_env_yaml = dict()
        local_env_yaml.update(self.env_yaml)
        product = utils.required_key(self.env_yaml, "product")
        rule_id = get_rule_dir_id(rule_dir_path)

        rule_path = os.path.join(rule_dir_path, "rule.yml")
        try:
            rule = Rule.from_yaml(rule_path, self.env_yaml)
        except DocumentationNotComplete:
            # Happens on non-debug builds when a rule isn't yet completed. We
            # don't want to build the SCE check for this rule yet so skip it
            # and move on.
            return

        local_env_yaml['rule_id'] = rule.id_
        local_env_yaml['rule_title'] = rule.title
        local_env_yaml['products'] = {product}

        for _path in get_rule_dir_sces(rule_dir_path, product):
            self._build_static_sce_check(rule_id, _path, local_env_yaml)

        self._build_templated_sce_check(rule)

    def _dump_metadata(self):
        # Finally, write out our metadata to disk so that we can reference it in
        # later build stages (such as during building shorthand content).
        metadata_path = os.path.join(self.output_dir, 'metadata.json')
        json.dump(self.already_loaded, open(metadata_path, 'w'))

    def _find_content_dirs(self):
        # We maintain the same search structure as build_ovals.py even though we
        # don't currently have any content under shared/checks/sce.
        product_dir = self.product_yaml["product_dir"]
        relative_guide_dir = utils.required_key(self.env_yaml, "benchmark_root")
        guide_dir = os.path.abspath(os.path.join(product_dir, relative_guide_dir))
        additional_content_directories = self.env_yaml.get(
            "additional_content_directories", [])
        add_content_dirs = [
            os.path.abspath(os.path.join(product_dir, rd))
            for rd in additional_content_directories
        ]
        return ([guide_dir] + add_content_dirs)

    def build(self):
        """
        Walks the content repository and builds all SCE checks (and metadata entry)
        into the output directory.
        """
        content_dirs = self._find_content_dirs()
        for _dir_path in find_rule_dirs_in_paths(content_dirs):
            self._build_rule(_dir_path)
        self._dump_metadata()