git.distorted.org.uk Git - u/mdw/putty/blob - contrib/kh2reg.py

   1 #! /usr/bin/env python
   2
   3 # $Id$
   4 # Convert OpenSSH known_hosts and known_hosts2 files to "new format" PuTTY
   5 # host keys.
   6 #   usage:
   7 #     kh2reg.py [ --win ] known_hosts1 2 3 4 ... > hosts.reg
   8 #       Creates a Windows .REG file (double-click to install).
   9 #     kh2reg.py --unix    known_hosts1 2 3 4 ... > sshhostkeys
  10 #       Creates data suitable for storing in ~/.putty/sshhostkeys (Unix).
  11 # Line endings are someone else's problem as is traditional.
  12 # Developed for Python 1.5.2.
  13
  14 import fileinput
  15 import base64
  16 import struct
  17 import string
  18 import re
  19 import sys
  20 import getopt
  21
  22 def winmungestr(s):
  23     "Duplicate of PuTTY's mungestr() in winstore.c:1.10 for Registry keys"
  24     candot = 0
  25     r = ""
  26     for c in s:
  27         if c in ' \*?%~' or ord(c)<ord(' ') or (c == '.' and not candot):
  28             r = r + ("%%%02X" % ord(c))
  29         else:
  30             r = r + c
  31         candot = 1
  32     return r
  33
  34 def strtolong(s):
  35     "Convert arbitrary-length big-endian binary data to a Python long"
  36     bytes = struct.unpack(">%luB" % len(s), s)
  37     return reduce ((lambda a, b: (long(a) << 8) + long(b)), bytes)
  38
  39 def longtohex(n):
  40     """Convert long int to lower-case hex.
  41
  42     Ick, Python (at least in 1.5.2) doesn't appear to have a way to
  43     turn a long int into an unadorned hex string -- % gets upset if the
  44     number is too big, and raw hex() uses uppercase (sometimes), and
  45     adds unwanted "0x...L" around it."""
  46
  47     plain=string.lower(re.match(r"0x([0-9A-Fa-f]*)l?$", hex(n), re.I).group(1))
  48     return "0x" + plain
  49
  50 output_type = 'windows'
  51
  52 try:
  53     optlist, args = getopt.getopt(sys.argv[1:], '', [ 'win', 'unix' ])
  54     if filter(lambda x: x[0] == '--unix', optlist):
  55         output_type = 'unix'
  56 except getopt.error, e:
  57     sys.stderr.write(str(e) + "\n")
  58     sys.exit(1)
  59
  60 if output_type == 'windows':
  61     # Output REG file header.
  62     sys.stdout.write("""REGEDIT4
  63
  64 [HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\SshHostKeys]
  65 """)
  66
  67 # Now process all known_hosts input.
  68 for line in fileinput.input(args):
  69
  70     try:
  71         # Remove leading/trailing whitespace (should zap CR and LF)
  72         line = string.strip (line)
  73
  74         # Skip blanks and comments
  75         if line == '' or line[0] == '#':
  76             raise "Skipping input line"
  77
  78         # Split line on spaces.
  79         fields = string.split (line, ' ')
  80
  81         # Common fields
  82         hostpat = fields[0]
  83         magicnumbers = []   # placeholder
  84         keytype = ""        # placeholder
  85
  86         # Grotty heuristic to distinguish known_hosts from known_hosts2:
  87         # is second field entirely decimal digits?
  88         if re.match (r"\d*$", fields[1]):
  89
  90             # Treat as SSH-1-type host key.
  91             # Format: hostpat bits10 exp10 mod10 comment...
  92             # (PuTTY doesn't store the number of bits.)
  93             magicnumbers = map (long, fields[2:4])
  94             keytype = "rsa"
  95
  96         else:
  97
  98             # Treat as SSH-2-type host key.
  99             # Format: hostpat keytype keyblob64 comment...
 100             sshkeytype, blob = fields[1], base64.decodestring (fields[2])
 101
 102             # 'blob' consists of a number of
 103             #   uint32    N (big-endian)
 104             #   uint8[N]  field_data
 105             subfields = []
 106             while blob:
 107                 sizefmt = ">L"
 108                 (size,) = struct.unpack (sizefmt, blob[0:4])
 109                 size = int(size)   # req'd for slicage
 110                 (data,) = struct.unpack (">%lus" % size, blob[4:size+4])
 111                 subfields.append(data)
 112                 blob = blob [struct.calcsize(sizefmt) + size : ]
 113
 114             # The first field is keytype again, and the rest we can treat as
 115             # an opaque list of bignums (same numbers and order as stored
 116             # by PuTTY). (currently embedded keytype is ignored entirely)
 117             magicnumbers = map (strtolong, subfields[1:])
 118
 119             # Translate key type into something PuTTY can use.
 120             if   sshkeytype == "ssh-rsa":   keytype = "rsa2"
 121             elif sshkeytype == "ssh-dss":   keytype = "dss"
 122             else:
 123                 raise "Unknown SSH key type", sshkeytype
 124
 125         # Now print out one line per host pattern, discarding wildcards.
 126         for host in string.split (hostpat, ','):
 127             if re.search (r"[*?!]", host):
 128                 sys.stderr.write("Skipping wildcard host pattern '%s'\n"
 129                                  % host)
 130                 continue
 131             elif re.match (r"\|", host):
 132                 sys.stderr.write("Skipping hashed hostname '%s'\n" % host)
 133                 continue
 134             else:
 135                 m = re.match (r"\[([^]]*)\]:(\d*)$", host)
 136                 if m:
 137                     (host, port) = m.group(1,2)
 138                     port = int(port)
 139                 else:
 140                     port = 22
 141                 # Slightly bizarre output key format: 'type@port:hostname'
 142                 # XXX: does PuTTY do anything useful with literal IP[v4]s?
 143                 key = keytype + ("@%d:%s" % (port, host))
 144                 value = string.join (map (longtohex, magicnumbers), ',')
 145                 if output_type == 'unix':
 146                     # Unix format.
 147                     sys.stdout.write('%s %s\n' % (key, value))
 148                 else:
 149                     # Windows format.
 150                     # XXX: worry about double quotes?
 151                     sys.stdout.write("\"%s\"=\"%s\"\n"
 152                                      % (winmungestr(key), value))
 153
 154     except "Unknown SSH key type", k:
 155         sys.stderr.write("Unknown SSH key type '%s', skipping\n" % k)
 156     except "Skipping input line":
 157         pass