1 files changed, 197 insertions, 0 deletions
diff --git a/scripts/digest.py b/scripts/digest.py
new file mode 100755
index 0000000..acff4c1
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+++ b/scripts/digest.py
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+#!/usr/bin/env python3
+
+__program_description ='''
+A script that digests the output of onion-grab.  Meant to be used for sorting
+out which domains set what Onion-Location values; as well as which domains set
+the same onion addresses when pruned to two labels.  See also stderr prints.
+'''
+
+import sys
+import argparse
+import logging
+
+log = logging.getLogger(__name__)
+
+import base64
+import hashlib
+
+def main(args):
+    input_lines = []
+    for inputFile in args.input_file:
+        with open(inputFile) as fp:
+            input_lines += [ line for line in fp ]
+
+    onion2domains, domain2onions, numHTTP, numHTML = parse_input(input_lines)
+    log.info(f'found {numHTTP} HTTP headers with Onion-Location')
+    log.info(f'found {numHTML} HTML meta attributes with Onion-Location')
+    log.info(f'found {len(domain2onions)} unqiue domain names that set Onion-Location')
+    log.info(f'found {len(onion2domains)} unique two-label onion addresses in the process')
+
+    log.info(f'storing domains with valid Onion-Location configurations in {args.output_domains}')
+    with open(args.output_domains, "w") as fp:
+        for d, o in domain2onions.items():
+            fp.write(f'{d} {" ".join(o)}\n')
+
+    log.info(f'storing two-label onion addresses that domains referenced in {args.output_onions}')
+    with open(args.output_onions, "w") as fp:
+        for o, d in onion2domains.items():
+            fp.write(f'{o} {" ".join(d)}\n')
+
+
+def parse_input(lines):
+    '''
+    Outputs the following two dictionaries and integers:
+    - onion2domain: key is a unique two-label onion address; the value is a list
+      of domain names that referenced it with Onion-Location.
+    - domain2onion: key is the domain name that configured Onion-Location; the
+      value is a non-modified list of onion URLs, i.e., including an http or
+      https scheme, subdomains (if any), port (if any), and path (if any).
+    - number of valid HTTP headers (at most one per non-unique domain)
+    - number of valid HTML meta attributes (at most one per non-unique domain)
+    '''
+    onion2domain = {}
+    domain2onion = {}
+    numHTTP = 0
+    numHTML = 0
+    for line in lines:
+        try:
+            line = line[:len(line)-1]
+            domain, onions, isHTTP, isHTML = parse_line(line)
+            for onion in onions:
+                addr = trim_onion(trimPath(trimScheme(onion)))
+
+                onion2domain.setdefault(addr, [])
+                onion2domain[addr] += [ domain ]
+
+                domain2onion.setdefault(domain, [])
+                domain2onion[domain] += [ onion ]
+
+            if isHTTP:
+                numHTTP += 1
+            if isHTML:
+                numHTML += 1
+        except Exception as e:
+            log.debug(f'"{line}": {e}')
+
+    return deduplicate_values(onion2domain), deduplicate_values(domain2onion), numHTTP, numHTML
+
+def parse_line(line):
+    '''
+    Line format is:
+
+    <domain> http=[value] html=[value]
+
+    where at least one of http or html should have a value.  Note: there has
+    been no vetting of what <value> is.  Outputs domain and a list of values,
+    and bolean values indicating if the domain used an HTTP and/or HTML config.
+    '''
+    s = line.split(" ")
+    if len(s) != 3:
+        raise Exception(f'invalid line split')
+
+    domain = s[0]
+    http2onion = s[1]
+    html2onion = s[2]
+    onions = []
+
+    isHTTP = False
+    s = http2onion.split("=")
+    if len(s) < 2:
+        raise Exception(f'invalid http split')
+    if len(s[1]) > 1:
+        onions += [ "=".join(s[1:]) ]
+        isHTTP = True
+
+    isHTML = False
+    s = html2onion.split("=")
+    if len(s) < 2:
+        raise Exception(f'invalid html split')
+    if len(s[1]) > 1:
+        onions += [ "=".join(s[1:]) ]
+        isHTML = True
+
+    if isHTTP and isHTML:
+        log.debug(f'{domain} sets both http header and html attribute')
+
+    return domain, onions, isHTTP, isHTML
+
+def trimScheme(url):
+    '''
+    Removes required http:// or https:// scheme from url.
+    '''
+    for scheme in [ "http://", "https://" ]:
+        if url.startswith(scheme):
+            return url[len(scheme):]
+
+    raise Exception(f'no http or https scheme')
+
+def trimPath(url):
+    '''
+    Trims the path off from the url.
+    '''
+    return url.split("/")[0]
+
+def trim_onion(host):
+    '''
+    Parses host as a v3 onion address, ports and subdomains are trimmed.
+    '''
+    s = host.split(":")
+    if len(s) > 2:
+        raise Exception(f'invalid host name')
+    if len(s) == 2:
+        port = int(s[1])
+        if port < 1 or port > 2**16 - 1:
+            raise Exception(f'port number not in [1, {2**16 - 1}]')
+
+    domain = s[0]
+    s = domain.split(".")
+    if len(s) < 2:
+        raise Exception(f'too few labels to be an onion address')
+    if s[len(s)-1] != "onion":
+        raise Exception(f'the final DNS label must be "onion"')
+    if len(s[len(s)-2]) != 56:
+        raise Exception(f'the DNS label before ".onion" must be 56 bytes')
+
+    assert_v3(base64.b32decode(s[len(s)-2].upper().encode('UTF-8')))
+    return ".".join(s[len(s)-2:])
+
+def assert_v3(blob):
+    '''
+    https://gitweb.torproject.org/torspec.git/tree/rend-spec-v3.txt#n2240
+    '''
+    pubkey = blob[:32]
+    checksum = blob[32:34]
+    version = blob[34:35]
+    if version[0] != 3:
+        raise Exception(f'invalid version: {version[0]}')
+
+    h = hashlib.sha3_256()
+    h.update(b'.onion checksum')
+    h.update(pubkey)
+    h.update(version)
+    c = h.digest()
+    if checksum[0] != c[0] or checksum[1] != c[1]:
+        raise Exception(f'invalid checksum')
+
+def deduplicate_values(key2values):
+    for key in key2values:
+        key2values[key] = sorted(list(set(key2values[key])))
+
+    return key2values
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description=__program_description)
+    parser.add_argument("-v", "--verbosity", type=str, default="info",
+            help="logging verbosity, select from debug, info, warning, error, and critical")
+    parser.add_argument("-o", "--output-onions", required=False, type=str, default="onions.txt",
+            help="path to output file keyed on two-label onion addresses")
+    parser.add_argument("-d", "--output-domains", required=False, type=str, default="domains.txt",
+            help="path to output file keyed on domains with Onion-Location")
+    parser.add_argument('-i','--input-file', nargs='+', required=True,
+            help='input file with collected data')
+
+    args = parser.parse_args()
+    logging.basicConfig(level=logging.__dict__[args.verbosity.upper()],
+            format='%(filename)s:%(lineno)d %(levelname)s: %(message)s')
+
+    sys.exit(main(args))