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
|
# -*- coding: utf-8 -*-
# Copyright 2015-2020 Mike Fährmann
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
"""Methods to access sites behind Cloudflare protection"""
import re
import time
import operator
import collections
import urllib.parse
from . import text
from .cache import memcache
def is_challenge(response):
return (response.status_code == 503 and
response.headers.get("Server", "").startswith("cloudflare") and
b"jschl-answer" in response.content)
def is_captcha(response):
return (response.status_code == 403 and
b'name="captcha-bypass"' in response.content)
def solve_challenge(session, response, kwargs):
"""Solve Cloudflare challenge and get cfclearance cookie"""
parsed = urllib.parse.urlsplit(response.url)
root = parsed.scheme + "://" + parsed.netloc
cf_kwargs = {}
headers = cf_kwargs["headers"] = collections.OrderedDict()
params = cf_kwargs["data"] = collections.OrderedDict()
page = response.text
url = root + text.unescape(text.extract(page, 'action="', '"')[0])
headers["Referer"] = response.url
for inpt in text.extract_iter(page, "<input ", ">"):
name = text.extract(inpt, 'name="', '"')[0]
if name == "jschl_answer":
value = solve_js_challenge(page, parsed.netloc)
else:
value = text.unescape(text.extract(inpt, 'value="', '"')[0])
params[name] = value
time.sleep(4)
cf_kwargs["allow_redirects"] = False
cf_response = session.request("POST", url, **cf_kwargs)
cookies = {
cookie.name: cookie.value
for cookie in cf_response.cookies
}
if not cookies:
import logging
log = logging.getLogger("cloudflare")
log.debug("Headers:\n%s", cf_response.headers)
log.debug("Content:\n%s", cf_response.text)
return cf_response, None, None
domain = next(iter(cf_response.cookies)).domain
cookies["__cfduid"] = response.cookies.get("__cfduid", "")
return cf_response, domain, cookies
def solve_js_challenge(page, netloc):
"""Evaluate JS challenge in 'page' to get 'jschl_answer' value"""
# build variable name
# e.g. '...f, wqnVscP={"DERKbJk":+(...' --> wqnVscP.DERKbJk
data, pos = text.extract_all(page, (
('var' , ',f, ', '='),
('key' , '"' , '"'),
('expr', ':' , '}'),
))
variable = "{}.{}".format(data["var"], data["key"])
vlength = len(variable)
# evaluate the initial expression
solution = evaluate_expression(data["expr"], page, netloc)
# iterator over all remaining expressions
# and combine their values in 'solution'
expressions = text.extract(
page, "'challenge-form');", "f.submit();", pos)[0]
for expr in expressions.split(";")[1:]:
if expr.startswith(variable):
# select arithmetc function based on operator (+/-/*)
func = OPERATORS[expr[vlength]]
# evaluate the rest of the expression
value = evaluate_expression(expr[vlength+2:], page, netloc)
# combine expression value with our current solution
solution = func(solution, value)
elif expr.startswith("a.value"):
if "t.length)" in expr:
# add length of hostname
solution += len(netloc)
if ".toFixed(" in expr:
# trim solution to 10 decimal places
solution = "{:.10f}".format(solution)
return solution
def evaluate_expression(expr, page, netloc, *,
split_re=re.compile(r"[(+]+([^)]*)\)")):
"""Evaluate a single Javascript expression for the challenge"""
if expr.startswith("function(p)"):
# get HTML element with ID k and evaluate the expression inside
# 'eval(eval("document.getElementById(k).innerHTML"))'
k, pos = text.extract(page, "k = '", "'")
e, pos = text.extract(page, 'id="'+k+'"', '<')
return evaluate_expression(e.partition(">")[2], page, netloc)
if "/" in expr:
# split the expression in numerator and denominator subexpressions,
# evaluate them separately,
# and return their fraction-result
num, _, denom = expr.partition("/")
num = evaluate_expression(num, page, netloc)
denom = evaluate_expression(denom, page, netloc)
return num / denom
if "function(p)" in expr:
# split initial expression and function code
initial, _, func = expr.partition("function(p)")
# evaluate said expression
initial = evaluate_expression(initial, page, netloc)
# get function argument and use it as index into 'netloc'
index = evaluate_expression(func[func.index("}")+1:], page, netloc)
return initial + ord(netloc[int(index)])
# iterate over all subexpressions,
# evaluate them,
# and accumulate their values in 'result'
result = ""
for subexpr in split_re.findall(expr) or (expr,):
result += str(sum(
VALUES[part]
for part in subexpr.split("[]")
))
return int(result)
OPERATORS = {
"+": operator.add,
"-": operator.sub,
"*": operator.mul,
}
VALUES = {
"": 0,
"+": 0,
"!+": 1,
"!!": 1,
"+!!": 1,
}
@memcache(keyarg=0)
def cookies(category):
return None
|
