sshvis Webapp source code <http://sshvis.appspot.com>

app.yaml

application: sshvis-hrd
version: 15
runtime: python27
api_version: 1
threadsafe: no 

handlers:
- url: .*
  script: main.py

index.yaml

indexes:

# AUTOGENERATED

# This index.yaml is automatically updated whenever the dev_appserver
# detects that a new type of query is run.  If you want to manage the
# index.yaml file manually, remove the above marker line (the line
# saying "# AUTOGENERATED").  If you want to manage some indexes
# manually, move them above the marker line.  The index.yaml file is
# automatically uploaded to the admin console when you next deploy
# your application using appcfg.py.

main.py

#!/usr/bin/env python
"""
  OpenSSH key fingerprint visualization web app
 
  Copyright (c) 2008 Dirk Loss
 
  Original SSH key fingerprint visualization 
  idea and C implementation by Alexander von Gernler.
  Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
 
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.
 
  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""

import cgi
import md5
import random

from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app


augmentation_strings = {"ssh-chars" : " .o+=*BOX@%&#/^SE",
                        "count" :     " 123456789abcdeSE",
                        "bubble" :    " .oO8@XY#abcdefSE",
                        "fences" :    " ##############SE",
                        "ats" :       " @@@@@@@@@@@@@@SE"}



def draw_ascii_field(left, right=None, size_x=17, size_y=9, augmentation_string=" .o+=*BOX@%&#/^SE"):
    """ Return a nice ASCII visualization of one or two given fields """
 
    length = len(augmentation_string) - 1

    sep = " "*6
    
    # Upper border
    out = "+%s+" % ("-" * size_x)
    if right is not None:
        out += "%s+%s+" % (sep, "-"*size_x)
    out += "\n"
  
    # Content
    for y in range(size_y):
        out += '|'
        for x in range(size_x):
            out += augmentation_string[min(left[x][y], length)]
        out += "|"
        if right is not None:
            out += sep 
            out += '|'
            for x in range(size_x):
                out += augmentation_string[min(right[x][y], length)]
            out += "|"
        out += "\n"
 
    # lower border
    out += "+%s+" % ("-" * size_x)
    if right is not None:
        out += "%s+%s+" % (sep, "-"*size_x)
    return out

def draw_html_field(left, right=None, size_x=17, size_y=9, augmentation_string=" .o+=*BOX@%&#/^SE"):
    """ Return a nice HTML visualization of one or two given fields """
 
    colors = ["dddddd", "bbbbbb", "999999", "777777", "555555", "333333", "111111", "bbbb00",
              "999900", "777700", "555500", "333300", "111100", "1100110", "f0f0f0", "669933", "ff6633"]

    # Every value the same. Start and end marked
    colors = ["dddddd"]
    for i in range(14): 
        colors.append("CC9966")
    colors.append("669933")
    colors.append("ff6633") 

    #header = '<colgroup width="%(width)s" span="%(span)s"></colgroup>' \ % {'width' = 
    rows = ""
    for y in range(size_y):
        row = ""
        for x in range(size_x):
            value = left[x][y]
#            row += '<td bgcolor="#%s">&nbsp;</td>' % colors[value]
            row += '<td bgcolor="#%s"><pre>%s</pre></td>' % (colors[value], augmentation_string[value])
        rows += '<tr>%s</tr>\n' % row
    return """
       <table border="0">
       %s
       </table> """ % rows
   

def visual_field(digest, size_x=17, size_y=9,
                augmentation_string=" .o+=*BOX@%&#/^SE",
                show_ends=True, bounce_type="bounce"):
    """ Return the visualization for a binary digest """
    
    length = len(augmentation_string) - 1
    field = []
    for x in range(size_x):
        line = []
        for y in range(size_y):
            line.append(0)
        field.append(line)

    # initialize field
    x = size_x / 2
    y = size_y / 2
 
    # process raw key
    for c in digest:
        # each byte conveys four 2-bit move commands
        inp = ord(c)
        for b in range(4):
            # evaluate 2 bit, rest is shifted later
            if inp & 0x1:
                x += 1
            else:
                x -= 1
            if inp & 0x2: 
                y += 1 
            else:
                y -= 1

            if bounce_type == "torus":
                x = x % size_x
                y = y % size_y
            else:
                # assure we are still in bounds
                x = max(x, 0)
                y = max(y, 0)
                x = min(x, size_x - 1)
                y = min(y, size_y - 1)

            # augment the field
            if field[x][y] < length - 2:
                field[x][y] += 1

            inp = inp >> 2

    if show_ends:
        # Mark starting point in the middle
        field[size_x / 2][size_y / 2] = length - 1
        # Mark end point
        field[x][y] = length

    return field


def hex_md5(msg):
    
    m=md5.new()
    m.update(msg)
    d = m.hexdigest()
    return ":".join([ d[i:i+2] for i in range(0, len(d), 2)])

def html_selectionbox(name, values, selected=None):
    """ Return a HTML selection box, optionally with a given selection as default """
    
    options = []
    for val in values:
        if val == selected:
            options.append("<option selected>%s</option>" % val)
        else:
            options.append("<option>%s</option>" % val)
    options = "\n".join(options)
    html = '<select name="%s" size="1">%s</select>' % (name, options)
    return html
    
    
OUTPUT_STYLES = ["ASCII", "HTML"]
SIZES = ["3 * 3", "4 * 4", "5 * 5", "10 * 5", "10 * 10", "17 * 9", "20 * 20", "30 * 30", "80 * 40"]
AUGMENTATION_TYPES = ["ssh-chars", "count", "bubble", "fences", "ats"]
END_TYPES = ["show S/E", "no S/E"]
BOUNCE_TYPES = ["bounce", "torus"]

def header(hash="fc:94:b0:c1:e5:b0:98:7c:58:43:99:76:97:ee:9f:b7",
           size="17 * 9", output_style="ASCII", augmentation_type="ssh-chars",
           end_type="show S/E", bounce_type="bounce", is_random=False):
    """ Return page header with input form """

    if is_random:
        checked = " checked"
    else:
        checked = ""
    next_random = hex_md5(str(random.randint(0, 2**128)))
    
    
    out = """<html>
         <body>
            <h1> SSH Fingerprint Visualization </h1>
            <p>  Original <a href="http://www.undeadly.org/cgi?action=article&sid=20080615022750&mode=expanded&count=13">idea</a> and <a href="http://marc.info/?l=openbsd-cvs&m=121321826818823&w=2">C implementation</a> by <a href="http://pestilenz.org/~grunk/">Alexander von Gernler</a>. This web app by <a href="http://dirk-loss.de">Dirk Loss</a>.
            </p>
            <p>More info: <a href="http://dirk-loss.de/sshvis/drunken_bishop.pdf">The drunken bishop</a>: An analysis of the OpenSSH fingerprint visualization algorithm (<a href="http://dirk-loss.de/sshvis/drunken_bishop.pdf">PDF</a>)</p>
            <form action="/" method="post">
              Fingerprint: <input type="text" name="hash" size="47" value="%s">
              <input type="submit" value="Generate Visualization">
              <br>Parameters:
              %s %s %s %s %s
              <input type="checkbox" name="is_random" value="%s"%s>randomize
              <br>
            </form>""" % (hash,
                          html_selectionbox("size", SIZES, selected=size),
                        html_selectionbox("output_style", OUTPUT_STYLES, selected=output_style),
                          html_selectionbox("augmentation_type", AUGMENTATION_TYPES, selected=augmentation_type),
                          html_selectionbox("end_type", END_TYPES, selected=end_type),
                          html_selectionbox("bounce_type", BOUNCE_TYPES, selected=bounce_type),
                          next_random,
                          checked)
    return out


class MainPage(webapp.RequestHandler):
    def get(self):
        """ Process HTTP GET request """
        
        self.response.out.write(header())
        self.response.out.write("""</body></html>""")

    def post(self):
        """ Process HTTP POST request """
        
        hash = cgi.escape(self.request.get('hash')) #.encode("utf-8")
        size = cgi.escape(self.request.get('size'))
        output_style = cgi.escape(self.request.get('output_style'))
        augmentation_type = cgi.escape(self.request.get('augmentation_type'))
        try:
            augmentation_string = augmentation_strings[augmentation_type]
        except KeyError:
            augmentation_string = augmentation_strings["ssh-chars"]
        try:
            size_x, sep, size_y = size.split()
            size_x = int(size_x)
            size_y = int(size_y)
        except (ValueError, AttributeError):
            size_x = 17
            size_y = 9
        end_type = cgi.escape(self.request.get('end_type'))
        if end_type == "no S/E":
            show_ends = False
        else:
            show_ends = True
        bounce_type = cgi.escape(self.request.get('bounce_type'))
        is_random = cgi.escape(self.request.get('is_random'))
        if is_random:
            hash = is_random

        # Header
        write = self.response.out.write  # shortcut
        write(header(hash, size, output_style, augmentation_type, end_type, bounce_type, is_random))

        try:
            hash = "".join(hash.replace(" ","").split(":")).decode("hex")
        except (TypeError, ValueError):
            write("""<p>Illegal input format. Fingerprint must be given as even-length hex string.
                      Colons may be left out. Spaces are ignored.</p>
                     <form action="/" method="post">
            <input type="hidden" name="hash" value="%s">
            <input type="hidden" name="size" value="%s">
            <input type="hidden" name="output_style" value="%s">
            <input type="hidden" name="augmentation_type" value="%s">
            <input type="hidden" name="end_type" value="%s">
            <input type="hidden" name="bounce_type" value="%s">
            <input type="submit" value="Convert to MD5 hash">
           </form>""" % (hex_md5(hash), size, output_style, augmentation_type, end_type, bounce_type))
           
        else:
            field = visual_field(hash, size_x, size_y, augmentation_string, show_ends, bounce_type)
            if output_style == "HTML":
                viz = draw_html_field(field, size_x=size_x, size_y=size_y, augmentation_string=augmentation_string)
                write(viz)
            else:
                viz = draw_ascii_field(field, size_x=size_x, size_y=size_y, augmentation_string=augmentation_string)
                write('<pre>')
                write(viz)
                write('</pre></body></html>')


def main():
  application = webapp.WSGIApplication(
                                     [('/', MainPage)],
                                     debug=False)
  run_wsgi_app(application)


if __name__ == "__main__":
  main()