homer.py 11 KB
Newer Older
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
1
2
3
4
5
6
7
8
#!/usr/bin/env python3

# http://pycurl.io/docs/latest
import pycurl

# http://www.dnspython.org/
import dns.message

9
10
11
12
13
# Octobre 2019: the Python GnuTLS bindings don't work with Python 3. So we use OpenSSL.
# https://www.pyopenssl.org/
# https://pyopenssl.readthedocs.io/
import OpenSSL

Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
14
15
16
17
18
19
import io
import sys
import base64
import getopt
import urllib.parse
import time
20
21
import socket
import ctypes
22
import re
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
23

24
# Values that can be changed from the command line
25
dot = False # DoH by default
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
26
27
28
29
30
31
post = False
verbose = False
insecure = False
head = False
rtype = 'AAAA'
tests = 1 # Number of repeated tests
32
ifile = None # Input file
33
delay = None
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
34

35
36
37
# Do not change these
re_host = re.compile(r'^([0-9a-z][0-9a-z-\.]*)|([0-9:]+)|([0-9\.])$')

Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
38
39
40
41
42
43
44
45
46
47
48
def error(msg=None):
    if msg is None:
        msg = "Unknown error"
    print(msg,file=sys.stderr)
    sys.exit(1)
    
def usage(msg=None):
    if msg:
        print(msg,file=sys.stderr)
    print("Usage: %s [-P] [-k] url domain-name [DNS type]" % sys.argv[0], file=sys.stderr)

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
def is_valid_hostname(name):
    name = str(name.encode('idna').lower())
    return re_host.search(name)
    
def is_valid_url(url):
  try:
    result = urllib.parse.urlparse(url) # A very poor validation, many
    # errors (for instance whitespaces, IPv6 address litterals without
    # brackets...) are ignored.
    return (result.scheme=="https" and result.netloc != "")
  except ValueError:
    return False

def get_certificate_san(x509cert):
    san = ""
    ext_count = x509cert.get_extension_count()
    for i in range(0, ext_count):
        ext = x509cert.get_extension(i)
        if "subjectAltName" in str(ext.get_short_name()):
            san = str(ext)
    return san

def validate_hostname(hostname, cert):
    hostname = hostname.lower()
    cn = cert.get_subject().commonName.lower()
    if cn.startswith("*."): # Wildcard
        (start, base) = cn.split("*.")
        if hostname.endswith(base):
            return True
    else:
        if hostname == cn:
            return True
    for alt_name in get_certificate_san(cert).split(", "):
        if alt_name.startswith("DNS:"):
            (start, base) = alt_name.split("DNS:")
            base = base.lower()
            if hostname == base:
                return True
        elif alt_name.startswith("IP Address:"):
            (start, base) = alt_name.split("IP Address:")
            base = base.lower()
            if base.endswith("\n"):
                base = base[:-1]
            if hostname == base: # TODO better canonicaliztion of IP addresses with the netaddr module
                return True
        else:
            pass # Ignore unknown alternative name types
    return False

98
99
class Connection:
    def __init__(self, server, dot=False, verbose=verbose, insecure=insecure, post=post, head=head):
100
101
102
103
        if dot and not is_valid_hostname(server):
            error("DoT requires a host name, not \"%s\"" % server)
        if not dot and not is_valid_url(url):
            error("DoH requires a valid HTTPS URL, not \"%s\"" % server)
104
105
106
107
108
109
110
111
        self.server = server
        self.dot = dot
        if not self.dot:
            self.post = post
            self.head = head
        self.verbose = verbose
        self.insecure = insecure
        if self.dot:
112
113
114
            addrinfo = socket.getaddrinfo(server, 853)
            # May be loop over the results of getaddrinfo, to test all the IP addresses?
            self.sock = socket.socket(addrinfo[0][0], socket.SOCK_STREAM)
115
116
117
118
            # With typical DoT servers, we *must* use TLS 1.2 (otherwise,
            # do_handshake fails with "OpenSSL.SSL.SysCallError: (-1, 'Unexpected
            # EOF')" Typical HTTP servers are more lax.
            self.context = OpenSSL.SSL.Context(OpenSSL.SSL.TLSv1_2_METHOD)
119
120
121
122
123
124
125
126
127
            # TODO set_tlsext_host_name(name) for SNI?
            if self.insecure:
                self.context.set_verify(OpenSSL.SSL.VERIFY_NONE, lambda *x: True)
            else:
                self.context.set_default_verify_paths()
                self.context.set_verify_depth(4) # Seems ignored
                self.context.set_verify(OpenSSL.SSL.VERIFY_PEER | OpenSSL.SSL.VERIFY_FAIL_IF_NO_PEER_CERT | \
                                        OpenSSL.SSL.VERIFY_CLIENT_ONCE,
                                        lambda conn, cert, errno, depth, preverify_ok: preverify_ok)
128
129
130
131
            self.session = OpenSSL.SSL.Connection(self.context, self.sock)
            self.session.connect((self.server, 853)) 
            self.session.do_handshake()
            self.cert = self.session.get_peer_certificate()
132
133
134
135
136
            if not insecure:
                valid = validate_hostname(server, self.cert)
                if not valid:
                    error("Certificate error: \"%s\" is not in the certificate" % server)
                # TODO validate with SPKI?
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
        else: # DoH
            self.curl = pycurl.Curl()
            self.url = server
            # Does not work if pycurl was not compiled with nghttp2 (recent Debian
            # packages are OK) https://github.com/pycurl/pycurl/issues/477
            self.curl.setopt(pycurl.HTTP_VERSION, pycurl.CURL_HTTP_VERSION_2)
            self.curl.setopt(pycurl.HTTPHEADER, ["Content-type: application/dns-message"])
            if self.verbose:
                self.curl.setopt(self.curl.VERBOSE, True)
            if self.insecure:
                self.curl.setopt(pycurl.SSL_VERIFYPEER, False)   
                self.curl.setopt(pycurl.SSL_VERIFYHOST, False)
            if self.head:
                self.curl.setopt(pycurl.NOBODY, True)
            if self.post:
                 self.curl.setopt(pycurl.POST, True)
    def __str__(self):
        return self.server
    def end(self):
        if self.dot:
            self.session.shutdown()
            self.session.close()
        else: # DoH
            self.curl.close()
            
# Routine doing one actual test. Returns a tuple, first member is a
163
164
165
# result (boolean indicating success for DoT, HTTP status code for
# DoH), second member is a DNS message (or a string if there is an
# error).
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
def do_test(connection, qname, qtype=rtype):
    message = dns.message.make_query(qname, dns.rdatatype.from_text(qtype))
    if connection.dot:
        # TODO Check what the Query ID is. Really random?
        messagew = message.to_wire() 
        length = len(messagew)
        n = connection.session.send(length.to_bytes(2, byteorder='big') + messagew)
        buf = connection.session.recv(2) 
        received = int.from_bytes(buf, byteorder='big')
        buf = connection.session.recv(received)
        response = dns.message.from_wire(buf) # TODO check the Query ID
        return (True, response)
    else: # DoH
        message.id = 0 # DoH requests that
        if connection.post:
181
            connection.curl.setopt(connection.curl.URL, connection.server)
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
            data = message.to_wire()
            connection.curl.setopt(pycurl.POSTFIELDS, data)
        else:
            dns_req = base64.urlsafe_b64encode(message.to_wire()).decode('UTF8').rstrip('=')
            connection.curl.setopt(connection.curl.URL, connection.server + ("?dns=%s" % dns_req))
        buffer = io.BytesIO()
        connection.curl.setopt(connection.curl.WRITEDATA, buffer)
        connection.curl.perform()
        rcode = connection.curl.getinfo(pycurl.RESPONSE_CODE)
        ok = True
        if rcode == 200:
            if not head:
                body = buffer.getvalue()
                try:
                    response = dns.message.from_wire(body)
                except dns.message.TrailingJunk: # Not DNS. 
                    response = "ERROR Not proper DNS data \"%s\"" % body
                    ok = False
            else:
                response = "HEAD successful"
        else:
203
            ok = False
204
205
            body =  buffer.getvalue()
            if len(body) == 0:
206
207
208
209
                response = "[No details]"
            else:
                response = body
            buffer.close()
210
211
        return (rcode, response)
    
212
213
214
# Main program
name = None
message = None
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
215
try:
216
217
    optlist, args = getopt.getopt (sys.argv[1:], "hvPker:f:d:t",
                                   ["help", "verbose", "dot", "head", "insecure", "POST", "repeat=", "file=", "delay="])
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
218
219
220
221
222
223
224
225
    for option, value in optlist:
        if option == "--help" or option == "-h":
            usage()
            sys.exit(0)
        elif option == "--verbose" or option == "-v":
            verbose = True
        elif option == "--head" or option == "-e":
            head = True
226
227
        elif option == "--dot" or option == "-t":
            dot = True
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
228
229
230
231
232
233
234
235
        elif option == "--insecure" or option == "-k":
            insecure = True
        elif option == "--POST" or option == "-P":
            post = True
        elif option == "--repeat" or option == "-r":
            tests = int(value)
            if tests <= 1:
                error("--repeat needs a value > 1")
236
237
238
239
        elif option == "--delay" or option == "-d":
            delay = float(value)
            if delay <= 0:
                error("--delay needs a value > 0")
240
241
        elif option == "--file" or option == "-f":
            ifile = value
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
242
243
244
245
246
        else:
            error("Unknown option %s" % option)
except getopt.error as reason:
    usage(reason)
    sys.exit(1)
247
248
if tests <= 1 and delay is not None:
    error("--delay makes no sense if there is no repetition")
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
249
250
251
if post and head:
    usage("POST or HEAD but not both")
    sys.exit(1)
252
253
254
if dot and (post or head):
    usage("POST or HEAD makes non sense for DoT")
    sys.exit(1)    
255
if ifile is None and (len(args) != 2 and len(args) != 3):
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
256
257
    usage("Wrong number of arguments")
    sys.exit(1)
258
259
260
if ifile is not None and len(args) != 1:
    usage("Wrong number of arguments (if --file is used, do not indicate the domain name)")
    sys.exit(1)
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
261
url = args[0]
262
263
264
265
if ifile is None:
    name = args[1]
    if len(args) == 3:
        rtype = args[2]
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
266
ok = True
267
conn = Connection(url, dot=dot, verbose=verbose, insecure=insecure, post=post, head=head)
268
start = time.time() 
269
270
if ifile is not None:
    input = open(ifile)
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
271
for i in range (0, tests):
272
273
274
275
276
277
278
279
280
281
282
    if tests > 1:
        print("\nTest %i" % i)
    if ifile is not None:
        line = input.readline()
        if line[:-1] == "":
            error("Not enough data in %s for the %i tests" % (ifile, tests))
        if line.find(' ') == -1:
            name = line[:-1]
            rtype = 'AAAA'
        else:
            (name, rtype) = line.split()
283
284
285
    (rcode, msg) = do_test(conn, name, rtype)
    if (dot and rcode) or (not dot and rcode == 200):
        print(msg)
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
286
    else:
287
288
289
290
        if dot:
            print("Error: %s" % msg, file=sys.stderr)
        else:
            print("HTTP error %i: %s" % (rcode, msg), file=sys.stderr)
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
291
        ok = False
292
293
    if tests > 1 and i == 0:
        start2 = time.time()
294
295
    if delay is not None:
        time.sleep(delay)
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
296
stop = time.time()
297
298
299
300
301
302
303
if tests > 1:
    extra = ", %.2f ms/request if we ignore the first one" % ((stop-start2)*1000/(tests-1))
else:
    extra = ""
print("\nTotal elapsed time: %.2f seconds (%.2f ms/request %s)" % (stop-start, (stop-start)*1000/tests, extra))
if ifile is not None:
    input.close()
304
conn.end()
Stephane Bortzmeyer's avatar
Stephane Bortzmeyer committed
305
306
307
308
309
if ok:
    sys.exit(0)
else:
    sys.exit(1)