# nvd.py -- simplistic NVD parser
# Copyright (C) 2005 Florian Weimer <fw@deneb.enyo.de>
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# 
# 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 General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""This module parses the XML files provided by the
National Vulnerability Database (NVD) <https://nvd.nist.gov/>
"""

import xml.sax
import xml.sax.handler

class _Parser(xml.sax.handler.ContentHandler):
    """Parser helper class."""

    def __init__(self):
        self.result = []
        self.start_dispatcher = {}
        for x in ('entry', 'local', 'network', 'local_network', 'user_init',
                  'avail', 'conf', 'int', 'sec_prot'):
             self.start_dispatcher[x] = getattr(self, 'TAG_' + x)
        self.path = []

    def _noop(*args):
        pass

    def startElement(self, name, attrs):
        self.path.append((name, attrs))
        self.start_dispatcher.get(name, self._noop)(name, attrs)

    def TAG_entry(self, name, attrs):
        self.name = attrs['name'].encode('utf-8')
        self.published = attrs['published'].encode('utf-8')
        self.severity = attrs.get('severity', u'').encode('utf-8')
        self.discovered = attrs.get('discovered', u'').encode('utf-8')

        self.cve_desc = ""
        self.range_local = self.range_remote = self.range_user_init = 0

        self.loss_avail = self.loss_conf = self.loss_int \
            = self.loss_sec_prot_user = self.loss_sec_prot_admin \
            = self.loss_sec_prot_other = 0

    def TAG_local(self, name, attrs):
        self.range_local = 1
    def TAG_network(self, name, attrs):
        self.range_remote = 1
    def TAG_local_network(self, name, attrs):
        self.range_remote = 1
    def TAG_user_init(self, name, attrs):
        self.range_user_init = 1
    def TAG_avail(self, name, attrs):
        self.loss_avail = 1
    def TAG_conf(self, name, attrs):
        self.loss_conf = 1
    def TAG_int(self, name, attrs):
        self.loss_int = 1
    def TAG_sec_prot(self, name, attrs):
        if 'user' in attrs:
            self.loss_sec_prot_user = 1
        if 'admin' in attrs:
            self.loss_sec_prot_admin = 1
        if 'other' in attrs:
            self.loss_sec_prot_other = 1
            
    def endElement(self, name):
        if name == 'entry':
            self.result.append((self.name,
                                self.cve_desc,
                                self.discovered,
                                self.published,
                                self.severity,
                                self.range_local,
                                self.range_remote,
                                self.range_user_init,
                                self.loss_avail,
                                self.loss_conf,
                                self.loss_int,
                                self.loss_sec_prot_user,
                                self.loss_sec_prot_admin,
                                self.loss_sec_prot_other))
        del self.path[-1]

    def characters(self, content):
        (name, attrs) = self.path[-1]
        if name == 'descript' and attrs['source'] == 'cve':
            self.cve_desc += content

def parse(file):
    """Parses the indicated file object.  Returns a list of tuples,
    containing the following elements:

    - CVE name
    - discovery data (can be empty)
    - publication date
    - severity (can be empty)
    - local range flag
    - remote range flag
    - availability loss type flag
    - confidentiality loss type flag
    - integrity loss type flag
    - security protection (user) loss type flag
    - security protection (admin) loss type flag
    - security protection (other) loss type flag
    """
    parser = xml.sax.make_parser()
    parser.setFeature(xml.sax.handler.feature_namespaces, 0)
    p = _Parser()
    parser.setContentHandler(p)
    parser.parse(file)
    return p.result

if __name__ == "__main__":
    import sys
    for name in sys.argv[1:]:
        parse(file(name))