196 lines
7.4 KiB
Python
Executable File
196 lines
7.4 KiB
Python
Executable File
#!/usr/bin/env python3.6
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#
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# Copyright (C) 2018 The University of Sheffield, UK
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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import sys
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import getopt
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import sqlite3
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from multiprocessing import Process, Queue, set_start_method
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from itertools import islice, groupby
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from operator import itemgetter
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import heapq
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def unique_justseen(iterable, key=None):
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"List unique elements, preserving order. Remember only the element just seen."
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# unique_justseen('AAAABBBCCDAABBB') --> A B C D A B
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# unique_justseen('ABBCcAD', str.lower) --> A B C A D
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return map(next, map(itemgetter(1), groupby(iterable, key)))
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class SimhashTable(Process):
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STOP = "stop"
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def __init__(self, splitter, outqueue, fp_it, q_it):
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super().__init__()
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self.outqueue = outqueue
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self.splitter = splitter
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self.table = {}
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self.fp_it = fp_it
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self.q_it = q_it
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@staticmethod
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def bit_count(n):
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return bin(n).count("1")
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def get_chunk(self, n):
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"""Reduces the simhash to a small chunk, given by self.splitters. The chunk will
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then be compared exactly in order to increase performance."""
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sum = 0
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for (s, c) in self.splitter:
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sum <<= c
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sum += (n >> s) & (pow(2, c) - 1)
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return sum
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def _add(self, fp):
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fp_chunk = self.get_chunk(fp[1])
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if not fp_chunk in self.table:
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self.table[fp_chunk] = []
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self.table[fp_chunk] += [fp]
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def _query(self, q):
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q_chunk = self.get_chunk(q)
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if q_chunk in self.table:
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for fp in self.table[q_chunk]:
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diff = SimhashTable.bit_count(q ^ fp[1])
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if diff < 4:
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yield (fp, diff)
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def run(self):
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for fp in self.fp_it:
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self._add(fp)
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for (q_info, q) in self.q_it:
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for ((fp_info, fp), diff) in self._query(q):
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self.outqueue.put((q_info, fp_info, diff))
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self.outqueue.put(SimhashTable.STOP)
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class SimhashBucket(Process):
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"""Implementation of http://wwwconference.org/www2007/papers/paper215.pdf"""
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def __init__(self, nr_of_tables, fp_it, q_it):
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super().__init__()
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# So far, we support the variants with 4 and 20 tables. Each element of splitters
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# describes the key for one table. The first element of the tuple indicates the number
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# of bits that we shift the simhash to the right; the second element indicates how many
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# bits, from the right side, we end up taking.
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if nr_of_tables == 4:
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splitters = [[(0, 16)], [(16, 16)], [(32, 16)], [(48, 16)]]
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elif nr_of_tables == 20:
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block_sizes = [11, 11, 11, 11, 10, 10]
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splitters = []
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for i in range(0, len(block_sizes)):
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for j in range(i + 1, len(block_sizes)):
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for k in range(j + 1, len(block_sizes)):
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splitters += [[
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(sum(block_sizes[i+1:]), block_sizes[i]),
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(sum(block_sizes[j+1:]), block_sizes[j]),
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(sum(block_sizes[k+1:]), block_sizes[k]),
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]]
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else:
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raise Exception(f"Unsupported number of tables: {nr_of_tables}")
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self.fp_it = fp_it
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self.q_it = q_it
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self.splitters = splitters
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self.tables = []
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self.outqueues = [Queue(100) for _ in range(len(self.splitters))]
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def run(self):
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self.tables = [SimhashTable(splitter, outqueue, self.fp_it, self.q_it) for (outqueue, splitter) in zip(self.outqueues, self.splitters)]
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for tbl in self.tables:
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tbl.start()
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for tbl in self.tables:
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tbl.join()
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def __iter__(self):
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return unique_justseen(heapq.merge(*[iter(q.get, SimhashTable.STOP) for q in self.outqueues]))
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def get_cdnjs_simhashes(db_path, limit=None):
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with sqlite3.connect(db_path) as db:
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for (simhash, library, path, size, typ, md5) in db.execute("select simhash, library, path, size, typ, md5 from cdnjs where "
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"simhash IS NOT NULL AND path like '%.js' and "
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"HEX(md5) <> 'd41d8cd98f00b204e9800998ecf8427e' order by path, size, typ, md5" +
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(f" LIMIT {int(limit)}" if limit is not None else "")):
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yield ((path, size, typ, md5.hex()), int(simhash))
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def get_crxfile_simhashes(db_path, extension_limit=None, crxfile_limit=None):
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with sqlite3.connect(db_path) as db:
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for (extid, date) in islice(db.execute("select extid, max(date) as date from extension group by extid order by extid"), extension_limit):
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for (crx_etag,) in db.execute("select crx_etag from extension where extid=? and date=? order by crx_etag", (extid, date)):
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for (path, md5, typ, simhash) in db.execute("select path, md5, typ, simhash from crxfile where crx_etag=? and simhash is not null and path like '%.js' order by path, md5, typ", (crx_etag,)):
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for (size,) in db.execute("select size from libdet where md5=? and typ=? and size >= 1024 order by size", (md5, typ)):
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yield ((extid, date, crx_etag, path, md5.hex(), typ, size), int(simhash))
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def print_help():
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print("""simhashbucket [OPTION] <DB_PATH>""")
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print(""" -h, --help print this help text""")
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print(""" --limit-cdnjs <N> only retrieve N rows""")
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print(""" --limit-extension <N> only retrieve N rows""")
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print(""" --limit-crxfile <N> only retrieve N rows""")
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print(""" --tables <N> number of tables to use for the bucket (4 or 20 so far)""")
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def parse_args(argv):
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limit_cdnjs = None
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limit_extension = None
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limit_crxfile = None
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tables = 20
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try:
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opts, args = getopt.getopt(argv, "h", [
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"limit-cdnjs=", "limit-extension=", "limit-crxfile=", "help", "tables="])
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except getopt.GetoptError:
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print_help()
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sys.exit(2)
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for opt, arg in opts:
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if opt == "--limit-cdnjs":
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limit_cdnjs = int(arg)
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elif opt == "--limit-extension":
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limit_extension = int(arg)
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elif opt == "--limit-crxfile":
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limit_crxfile = int(arg)
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elif opt == "--tables":
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tables = int(arg)
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if len(args) != 1:
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print_help()
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sys.exit(2)
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db_path = args[0]
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return limit_cdnjs, limit_extension, limit_crxfile, tables, db_path
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def main(args):
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limit_cdnjs, limit_extension, limit_crxfile, tables, db_path = parse_args(args)
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fp_it = get_cdnjs_simhashes(db_path, limit_cdnjs)
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q_it = get_crxfile_simhashes(db_path, limit_extension, limit_crxfile)
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bucket = SimhashBucket(tables, fp_it, q_it)
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bucket.start()
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for tup in bucket:
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sys.stdout.write("|".join([str(x) for x in tup]) + "\n")
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if __name__ == "__main__":
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main(sys.argv[1:])
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