mirror of
https://github.com/splunk/security_content
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divious1
122 lines
3.4 KiB
Python
Executable File
122 lines
3.4 KiB
Python
Executable File
# Copyright 2016 Splunk, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the 'License'): you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an 'AS IS' BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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'''
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This module contains simple interfaces for File compression and decompression.
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'''
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import gzip
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import cStringIO as StringIO
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import zipfile
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__all__ = ['GzipHandler',
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'ZipHandler']
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class GzipHandler(object):
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'''
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Class for handling gzip-formatted string content.
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'''
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@classmethod
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def check_format(cls, data):
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'''Validate `data` whether it is in gzip format.
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Bytes 0 and 1 should be (per RFC 1952):
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data[0] = 31 (0x1f), data[1] = 139 (0x8b).
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:param data: Data to check.
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:type data: ``bytes``
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:returns: True if it is in gzip format else False.
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:rtype: ``bool``
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'''
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return data[0:2] == '\x1f\x8b'
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@classmethod
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def decompress(cls, data):
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'''Decompress gzip-compressed data `data`.
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It will perform basic validation, then return the decompressed
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data or raises ValueError exception for invalid `data`.
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:param data: Gzip-compressed data to decompress.
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:type data: ``bytes``
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:returns: decompressed data.
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:rtype: ``string``
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:raises ValueError: If `data` is not in gzip format
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'''
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if not cls.check_format(data):
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raise ValueError('File is not gzip format.')
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return gzip.GzipFile(fileobj=StringIO.StringIO(data),
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mode='rb').read()
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class ZipHandler(object):
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'''
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Class for handling zip files.
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'''
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@classmethod
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def check_format(cls, data):
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'''Validate `data` whether it is in zip format.
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:param data: Data to check.
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:type data: ``bytes``
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:returns: True if it is in zip format else False.
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:rtype: ``bool``
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'''
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return zipfile.is_zipfile(StringIO.StringIO(data))
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@classmethod
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def decompress(cls, data):
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'''Decompress zip-compressed data `data`.
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It will perform basic validation, then return the decompressed
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data or raises ValueError exception with error message.
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:param data: Zip-compressed data to decompress.
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:type data: ``bytes``
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:returns: decompressed data.
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:rtype: ``string``
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:raises ValueError: If decompress data failed.
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'''
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if not cls.check_format(data):
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raise ValueError('File is not zip format.')
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fh = StringIO.StringIO(data)
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decompressor = zipfile.ZipFile(fh)
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files = decompressor.infolist()
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if len(files) > 1:
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raise ValueError(
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'Zip files containing multiple files not supported by this '
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'handler.')
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try:
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text = decompressor.read(files[0].filename)
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except:
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raise ValueError('Unknown exception when extracting zip file.')
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if len(text) != files[0].file_size:
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raise ValueError('Zip file size does not match actual size.')
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return text
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