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

   1 #! /usr/bin/env python
   2
   3 # $Id: kh2reg.py,v 1.1 2002/03/10 22:00:06 jacob Exp $
   4 # Convert OpenSSH known_hosts and known_hosts2 files to "new format" PuTTY
   5 # host keys in a Windows .REG file (double-click to install).
   6 #   usage: hosts2reg.py known_hosts1 2 3 4 ... > hosts.reg
   7 # Line endings are someone else's problem as is traditional.
   8 # Developed for Python 1.5.2.
   9
  10 import fileinput
  11 import base64
  12 import struct
  13 import string
  14 import re
  15 import sys
  16
  17 def mungestr(s):
  18     "Duplicate of PuTTY's mungestr() in winstore.c:1.10 for Registry keys"
  19     candot = 0
  20     r = ""
  21     for c in s:
  22         if c in ' \*?%~' or ord(c)<ord(' ') or (c == '.' and not candot):
  23             r = r + ("%%%02X" % ord(c))
  24         else:
  25             r = r + c
  26         candot = 1
  27     return r
  28
  29 def strtolong(s):
  30     "Convert arbitrary-length big-endian binary data to a Python long"
  31     bytes = struct.unpack(">%luB" % len(s), s)
  32     return reduce ((lambda a, b: (long(a) << 8) + long(b)), bytes)
  33
  34 def longtohex(n):
  35     """Convert long int to lower-case hex.
  36
  37     Ick, Python (at least in 1.5.2) doesn't appear to have a way to
  38     turn a long int into an unadorned hex string -- % gets upset if the
  39     number is too big, and raw hex() uses uppercase (sometimes), and
  40     adds unwanted "0x...L" around it."""
  41
  42     plain=string.lower(re.match(r"0x([0-9A-Fa-f]*)l?$", hex(n), re.I).group(1))
  43     return "0x" + plain
  44
  45 # Output REG file header.
  46 sys.stdout.write("""REGEDIT4
  47
  48 [HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\SshHostKeys]
  49 """)
  50
  51 # Now process all known_hosts input.
  52 for line in fileinput.input():
  53
  54     try:
  55         # Remove leading/trailing whitespace (should zap CR and LF)
  56         line = string.strip (line)
  57
  58         # Skip blanks and comments
  59         if line == '' or line[0] == '#':
  60             raise "Skipping input line"
  61
  62         # Split line on spaces.
  63         fields = string.split (line, ' ')
  64
  65         # Common fields
  66         hostpat = fields[0]
  67         magicnumbers = []   # placeholder
  68         keytype = ""        # placeholder
  69
  70         # Grotty heuristic to distinguish known_hosts from known_hosts2:
  71         # is second field entirely decimal digits?
  72         if re.match (r"\d*$", fields[1]):
  73
  74             # Treat as SSH1-type host key.
  75             # Format: hostpat bits10 exp10 mod10 comment...
  76             # (PuTTY doesn't store the number of bits.)
  77             magicnumbers = map (long, fields[2:4])
  78             keytype = "rsa"
  79
  80         else:
  81
  82             # Treat as SSH2-type host key.
  83             # Format: hostpat keytype keyblob64 comment...
  84             sshkeytype, blob = fields[1], base64.decodestring (fields[2])
  85
  86             # 'blob' consists of a number of
  87             #   uint32    N (big-endian)
  88             #   uint8[N]  field_data
  89             subfields = []
  90             while blob:
  91                 sizefmt = ">L"
  92                 (size,) = struct.unpack (sizefmt, blob[0:4])
  93                 size = int(size)   # req'd for slicage
  94                 (data,) = struct.unpack (">%lus" % size, blob[4:size+4])
  95                 subfields.append(data)
  96                 blob = blob [struct.calcsize(sizefmt) + size : ]
  97
  98             # The first field is keytype again, and the rest we can treat as
  99             # an opaque list of bignums (same numbers and order as stored
 100             # by PuTTY). (currently embedded keytype is ignored entirely)
 101             magicnumbers = map (strtolong, subfields[1:])
 102
 103             # Translate key type into something PuTTY can use.
 104             if   sshkeytype == "ssh-rsa":   keytype = "rsa2"
 105             elif sshkeytype == "ssh-dss":   keytype = "dss"
 106             else:
 107                 raise "Unknown SSH key type", sshkeytype
 108
 109         # Now print out one line per host pattern, discarding wildcards.
 110         for host in string.split (hostpat, ','):
 111             if re.search (r"[*?!]", host):
 112                 sys.stderr.write("Skipping wildcard host pattern '%s'\n"
 113                                  % host)
 114                 continue
 115             else:
 116                 # Slightly bizarre registry key format: 'type@port:hostname'
 117                 # As far as I know, the input never specifies a port.
 118                 port = 22
 119                 # XXX: does PuTTY do anything useful with literal IP[v4]s?
 120                 key = keytype + ("@%d:%s" % (port, host))
 121                 value = string.join (map (longtohex, magicnumbers), ',')
 122                 # XXX: worry about double quotes?
 123                 sys.stdout.write("\"%s\"=\"%s\"\n" % (mungestr(key), value))
 124
 125     except "Unknown SSH key type", k:
 126         sys.stderr.write("Unknown SSH key type '%s', skipping\n" % k)
 127     except "Skipping input line":
 128         pass