#!/usr/bin/env python
# -*- mode: python -*-

#   Prior copyright probably rmurray, troup, joey, jgg -- weasel 2008
#   Copyright (c) 2008 Peter Palfrader <peter@palfrader.org>
#   Copyright (c) 2008 Joerg Jaspert <joerg@debian.org>

import userdir_gpg, userdir_ldap, sys, traceback, time, ldap, os, commands
import pwd, tempfile

from userdir_gpg import *
from userdir_ldap import *

# Error codes from /usr/include/sysexits.h
ReplyTo = ConfModule.replyto;
PingFrom = ConfModule.pingfrom;
ChPassFrom = ConfModule.chpassfrom;
ChangeFrom = ConfModule.changefrom;
ReplayCacheFile = ConfModule.replaycachefile;
SSHFingerprintFile = ConfModule.fingerprintfile

UUID_FORMAT = '[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}'

EX_TEMPFAIL = 75;
EX_PERMFAIL = 65;      # EX_DATAERR
Error = 'Message Error';
SeenKey = 0;
SeenDNS = 0;
mailRBL = {}
mailRHSBL = {}
mailWhitelist = {}
SeenList = {}
DNS = {}
SudoPasswd = {}

SSHFingerprint = re.compile('^(\d+) ([0-9a-f\:]{47}) (.+)$')
SSHRSA1Match = re.compile('^^(.* )?\d+ \d+ \d+')

GenderTable = {"male": 1,
	       "1": 1,
	       "female": 2,
	       "2": 2,
	       "unspecified": 9,
	       "9": 9,
};

ArbChanges = {"c": "..",
	      "l": ".*",
	      "facsimileTelephoneNumber": ".*",
	      "telephoneNumber": ".*",
	      "postalAddress": ".*",
	      "postalCode": ".*",
              "loginShell": ".*",
              "emailForward": "^([^<>@]+@.+)?$",
              "jabberJID": "^([^<>@]+@.+)?$",
              "ircNick": ".*",
              "icqUin": "^[0-9]*$",
              "onVacation": ".*",
              "labeledURI": ".*",
              "birthDate": "^([0-9]{4})([01][0-9])([0-3][0-9])$",
              "mailDisableMessage": ".*",
	      "mailGreylisting": "^(TRUE|FALSE)$",
	      "mailCallout": "^(TRUE|FALSE)$",
	      "VoIP": ".*",
	      "gender": "^(1|2|9|male|female|unspecified)$",
};

DelItems = {"c": None,
            "l": None,
            "facsimileTelephoneNumber": None,
            "telephoneNumber": None,
            "postalAddress": None,
            "postalCode": None,
            "emailForward": None,
            "ircNick": None,
            "onVacation": None,
            "labeledURI": None,
	    "latitude": None,
	    "longitude": None,
            "icqUin": None,
            "jabberJID": None,
            "jpegPhoto": None,
            "dnsZoneEntry": None,
	    "sshRSAAuthKey": None,
            "birthDate" : None,
            "mailGreylisting": None,
            "mailCallout": None,
            "mailRBL": None,
            "mailRHSBL": None,
            "mailWhitelist": None,
            "mailDisableMessage": None,
            "VoIP": None,
            };


# Decode a GPS location from some common forms
def LocDecode(Str,Dir):
   # Check for Decimal degrees, DGM, or DGMS
   if re.match("^[+-]?[\d.]+$",Str) != None:
      return Str;

   Deg = '0'; Min = None; Sec = None; Dr = Dir[0];
   
   # Check for DDDxMM.MMMM where x = [nsew]
   Match = re.match("^(\d+)(["+Dir+"])([\d.]+)$",Str);
   if Match != None:
      G = Match.groups();
      Deg = G[0]; Min = G[2]; Dr = G[1];

   # Check for DD.DD x 
   Match = re.match("^([\d.]+) ?(["+Dir+"])$",Str);
   if Match != None:
      G = Match.groups();
      Deg = G[0]; Dr = G[1];

   # Check for DD:MM.MM x 
   Match = re.match("^(\d+):([\d.]+) ?(["+Dir+"])$",Str);
   if Match != None:
      G = Match.groups();
      Deg = G[0]; Min = G[1]; Dr = G[2];

   # Check for DD:MM:SS.SS x
   Match = re.match("^(\d+):(\d+):([\d.]+) ?(["+Dir+"])$",Str);
   if Match != None:
      G = Match.groups();
      Deg = G[0]; Min = G[1]; Sec = G[2]; Dr = G[3];
      
   # Some simple checks
   if float(Deg) > 180:
      raise "Failed","Bad degrees";
   if Min != None and float(Min) > 60:
      raise "Failed","Bad minutes";
   if Sec != None and float(Sec) > 60:
      raise "Failed","Bad seconds";
      
   # Pad on an extra leading 0 to disambiguate small numbers
   if len(Deg) <= 1 or Deg[1] == '.':
      Deg = '0' + Deg;
   if Min != None and (len(Min) <= 1 or Min[1] == '.'):
      Min = '0' + Min;
   if Sec != None and (len(Sec) <= 1 or Sec[1] == '.'):
      Sec = '0' + Sec;
   
   # Construct a DGM/DGMS type value from the components.
   Res = "+"
   if Dr == Dir[1]:
      Res = "-";
   Res = Res + Deg;
   if Min != None:
      Res = Res + Min;
   if Sec != None:
      Res = Res + Sec;
   return Res;
	      
# Handle changing a set of arbitary fields
#  <field>: value
def DoArbChange(Str,Attrs):
   Match = re.match("^([^ :]+): (.*)$",Str);
   if Match == None:
      return None;
   G = Match.groups();

   attrName = G[0].lower();
   for i in ArbChanges.keys():
      if i.lower() == attrName:
         attrName = i;
         break;
   if ArbChanges.has_key(attrName) == 0:
      return None;

   if re.match(ArbChanges[attrName],G[1]) == None:
      raise Error, "Item does not match the required format"+ArbChanges[attrName];

   value = G[1];
   if attrName == 'gender':
      if G[1] not in GenderTable:
         raise Error, "Gender not found in table"
      value = GenderTable[G[1]]

#   if attrName == 'birthDate':
#      (re.match("^([0-9]{4})([01][0-9])([0-3][0-9])$",G[1]) {
#    $bd_yr = $1; $bd_mo = $2; $bd_day = $3;
#    if ($bd_mo > 0 and $bd_mo <= 12 and $bd_day > 0) {
#      if ($bd_mo == 2) {
#	 if ($bd_day == 29 and ($bd_yr == 0 or ($bd_yr % 4 == 0 && ($bd_yr % 100 != 0 || $bd_yr % 400 == 0)))) {
#	   $bd_ok = 1;
#	 } elsif ($bd_day <= 28) {
#	   $bd_ok = 1;
#	 }
#      } elsif ($bd_mo == 4 or $bd_mo == 6 or $bd_mo == 9 or $bd_mo == 11) {
#	if ($bd_day <= 30) {
#	  $bd_ok = 1;
#	}
#      } else {
#	if ($bd_day <= 31) {
#	  $bd_ok = 1;
#	}
#      }
#    }
#  } elsif (not defined($query->param('birthdate')) or $query->param('birthdate') =~ /^\s*$/) {
#    $bd_ok = 1;
#  }
   Attrs.append((ldap.MOD_REPLACE,attrName,value));
   return "Changed entry %s to %s"%(attrName,value);

# Handle changing a set of arbitary fields
#  <field>: value
def DoDel(Str,Attrs):
   Match = re.match("^del (.*)$",Str);
   if Match == None:
      return None;
   G = Match.groups();

   attrName = G[0].lower();
   for i in DelItems.keys():
      if i.lower() == attrName:
         attrName = i;
         break;
   if DelItems.has_key(attrName) == 0:
      return "Cannot erase entry %s"%(attrName);

   Attrs.append((ldap.MOD_DELETE,attrName,None));
   return "Removed entry %s"%(attrName);

# Handle a position change message, the line format is:
#  Lat: -12412.23 Long: +12341.2342
def DoPosition(Str,Attrs):
   Match = re.match("^lat: ([+\-]?[\d:.ns]+(?: ?[ns])?) long: ([+\-]?[\d:.ew]+(?: ?[ew])?)$", Str.lower())
   if Match == None:
      return None;

   G = Match.groups();
   try:
      sLat = LocDecode(G[0],"ns");
      sLong = LocDecode(G[1],"ew");
      Lat = DecDegree(sLat,1);
      Long = DecDegree(sLong,1);
   except:
      raise Error, "Positions were found, but they are not correctly formed";

   Attrs.append((ldap.MOD_REPLACE,"latitude",sLat));
   Attrs.append((ldap.MOD_REPLACE,"longitude",sLong));
   return "Position set to %s/%s (%s/%s decimal degrees)"%(sLat,sLong,Lat,Long);

# Load bad ssh fingerprints
def LoadBadSSH():
   f = open(SSHFingerprintFile, "r")
   bad = []
   FingerprintLine = re.compile('^([0-9a-f\:]{47}).*$')
   for line in f.readlines():
      Match = FingerprintLine.match(line)
      if Match is not None:
         g = Match.groups()
         bad.append(g[0])
   return bad

# Handle an SSH authentication key, the line format is:
#  [options] 1024 35 13188913666680[..] [comment]
def DoSSH(Str, Attrs, badkeys, uid):
   Match = SSH2AuthSplit.match(Str);
   if Match == None:
      return None;
   g = Match.groups()
   typekey = g[1]
   if Match == None:
      Match = SSHRSA1Match.match(Str)
      if Match is not None:
         return "RSA1 keys not supported anymore"
      return None;

   (fd, path) = tempfile.mkstemp(".pub", "sshkeytry", "/tmp")
   f = open(path, "w")
   f.write("%s\n" % (Str))
   f.close()
   cmd = "/usr/bin/ssh-keygen -l -f %s < /dev/null" % (path)
   (result, output) = commands.getstatusoutput(cmd)
   os.remove(path)
   if (result != 0):
      raise Error, "ssh-keygen -l invocation failed!\n%s\n" % (output)


   # Head
   Date = time.strftime("%a, %d %b %Y %H:%M:%S +0000",time.gmtime(time.time()))
   ErrReplyHead = "From: %s\nCc: %s\nReply-To: %s\nDate: %s\n" % (os.environ['SENDER'],os.environ['SENDER'],ReplyTo,Date)
   Subst = {}
   Subst["__ADMIN__"] = ReplyTo
   Subst["__USER__"] = uid

   Match = SSHFingerprint.match(output)
   g = Match.groups()

   if int(g[0]) < 1024:
      try:
         # Body
         Subst["__ERROR__"] = "SSH keysize %s is below limit 1024" % (g[0])
         ErrReply = TemplateSubst(Subst,open(TemplatesDir+"admin-info","r").read())

         Child = os.popen("/usr/sbin/sendmail -t","w")
         Child.write(ErrReplyHead)
         Child.write(ErrReply)
         if Child.close() != None:
            raise Error, "Sendmail gave a non-zero return code"
      except:
         sys.exit(EX_TEMPFAIL)

      # And now break and stop processing input, which sends a reply to the user.
      raise Error, "SSH keys must have at least 1024 bits, processing halted, NOTHING MODIFIED AT ALL"
   elif g[1] in badkeys:
      try:
         # Body
         Subst["__ERROR__"] = "SSH key with fingerprint %s known as bad key" % (g[1])
         ErrReply = TemplateSubst(Subst,open(TemplatesDir+"admin-info","r").read())

         Child = os.popen("/usr/sbin/sendmail -t","w")
         Child.write(ErrReplyHead)
         Child.write(ErrReply)
         if Child.close() != None:
            raise Error, "Sendmail gave a non-zero return code"
      except:
         sys.exit(EX_TEMPFAIL)

      # And now break and stop processing input, which sends a reply to the user.
      raise Error, "Submitted SSH Key known to be bad and insecure, processing halted, NOTHING MODIFIED AT ALL"

   if (typekey == "dss"):
      return "DSA keys not accepted anymore"

   global SeenKey;
   if SeenKey:
     Attrs.append((ldap.MOD_ADD,"sshRSAAuthKey",Str));
     return "SSH Key added "+FormatSSHAuth(Str);
      
   Attrs.append((ldap.MOD_REPLACE,"sshRSAAuthKey",Str));
   SeenKey = 1;
   return "SSH Keys replaced with "+FormatSSHAuth(Str);

# Handle changing a dns entry
#  host IN A     12.12.12.12
#  host IN AAAA  1234::5678
#  host IN CNAME foo.bar.    <- Trailing dot is required
#  host IN MX    foo.bar.    <- Trailing dot is required
def DoDNS(Str,Attrs,DnRecord):
   cnamerecord = re.match("^[-\w]+\s+IN\s+CNAME\s+([-\w.]+\.)$",Str,re.IGNORECASE)
   arecord     = re.match('^[-\w]+\s+IN\s+A\s+(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})$',Str,re.IGNORECASE)
   mxrecord    = re.match("^[-\w]+\s+IN\s+MX\s+(\d{1,3})\s+([-\w.]+\.)$",Str,re.IGNORECASE)
   #aaaarecord  = re.match('^[-\w]+\s+IN\s+AAAA\s+((?:[0-9a-f]{1,4})(?::[0-9a-f]{1,4})*(?::(?:(?::[0-9a-f]{1,4})*|:))?)$',Str,re.IGNORECASE)
   aaaarecord  = re.match('^[-\w]+\s+IN\s+AAAA\s+([A-F0-9:]{2,39})$',Str,re.IGNORECASE)

   if cnamerecord == None and\
      arecord == None and\
      mxrecord == None and\
      aaaarecord == None:
     return None;

   # Check if the name is already taken
   G = re.match('^([-\w+]+)\s',Str)
   if G == None:
     raise Error, "Hostname not found although we already passed record syntax checks"
   hostname = G.group(1)

   # Check for collisions
   global l;
   # [JT 20070409 - search for both tab and space suffixed hostnames
   #  since we accept either.  It'd probably be better to parse the
   #  incoming string in order to construct what we feed LDAP rather
   #  than just passing it through as is.]
   filter = "(|(dnsZoneEntry=%s	*)(dnsZoneEntry=%s *))" % (hostname, hostname)
   Rec = l.search_s(BaseDn,ldap.SCOPE_ONELEVEL,filter,["uid"]);
   for x in Rec:
      if GetAttr(x,"uid") != GetAttr(DnRecord,"uid"):
         return "DNS entry is already owned by " + GetAttr(x,"uid")

   global SeenDNS;
   global DNS;

   if cnamerecord:
     if DNS.has_key(hostname):
       return "CNAME and other RR types not allowed: "+Str
     else:
       DNS[hostname] = 2
   else:
     if DNS.has_key(hostname) and DNS[hostname] == 2:
       return "CNAME and other RR types not allowed: "+Str
     else:
       DNS[hostname] = 1

   if cnamerecord != None:
     sanitized = "%s IN CNAME %s" % (hostname, cnamerecord.group(1))
   elif arecord != None:
     ipaddress = arecord.group(1)
     for quad in ipaddress.split('.'):
       if not (int(quad) >=0 and int(quad) <= 255):
         return "Invalid quad %s in IP address %s in line %s" %(quad, ipaddress, Str)
     sanitized = "%s IN A %s"% (hostname, ipaddress)
   elif mxrecord != None:
     priority = mxrecord.group(1)
     mx = mxrecord.group(2)
     sanitized = "%s IN MX %s %s" % (hostname, priority, mx)
   elif aaaarecord != None:
     ipv6address = aaaarecord.group(1)
     parts = ipv6address.split(':')
     if len(parts) > 8:
       return "Invalid IPv6 address (%s): too many parts"%(ipv6address)
     if len(parts) <= 2:
       return "Invalid IPv6 address (%s): too few parts"%(ipv6address)
     if parts[0] == "":
       parts.pop(0)
     if parts[-1] == "":
       parts.pop(-1)
     seenEmptypart = False
     for p in parts:
       if len(p) > 4:
         return "Invalid IPv6 address (%s): part %s is longer than 4 characters"%(ipv6address, p)
       if p == "":
         if seenEmptypart:
           return "Invalid IPv6 address (%s): more than one :: (nothing in between colons) is not allowed"%(ipv6address)
         seenEmptypart = True
     sanitized = "%s IN AAAA %s" % (hostname, ipv6address)
   else:
     raise Error, "None of the types I recognize was it.  I shouldn't be here.  confused."

   if SeenDNS:
     Attrs.append((ldap.MOD_ADD,"dnsZoneEntry",sanitized));
     return "DNS Entry added "+sanitized;

   Attrs.append((ldap.MOD_REPLACE,"dnsZoneEntry",sanitized));
   SeenDNS = 1;
   return "DNS Entry replaced with "+sanitized;

# Handle an RBL list (mailRBL, mailRHSBL, mailWhitelist)
def DoRBL(Str,Attrs):
   Match = re.compile('^mail(rbl|rhsbl|whitelist) ([-a-z0-9.]+)$').match(Str.lower())
   if Match == None:
      return None
   
   if Match.group(1) == "rbl":
      Key = "mailRBL"
   if Match.group(1) == "rhsbl":
      Key = "mailRHSBL"
   if Match.group(1) == "whitelist":
      Key = "mailWhitelist"
   Host = Match.group(2)

   global SeenList
   if SeenList.has_key(Key):
     Attrs.append((ldap.MOD_ADD,Key,Host))
     return "%s added %s" % (Key,Host)
      
   Attrs.append((ldap.MOD_REPLACE,Key,Host))
   SeenList[Key] = 1;
   return "%s replaced with %s" % (Key,Host)

# Handle a ConfirmSudoPassword request
def DoConfirmSudopassword(Str):
   Match = re.compile('^confirm sudopassword ('+UUID_FORMAT+') ([a-z0-9.,*]+) ([0-9a-f]{40})$').match(Str)
   if Match == None:
      return None

   uuid = Match.group(1)
   hosts = Match.group(2)
   hmac = Match.group(3)

   global SudoPasswd
   SudoPasswd[uuid] = (hosts, hmac)
   return "got confirm for sudo password %s on host(s) %s, auth code %s" % (uuid,hosts, hmac)

def FinishConfirmSudopassword(l, uid, Attrs):
   global SudoPasswd
   result = "\n"

   res = l.search_s(BaseDn,ldap.SCOPE_ONELEVEL,"uid="+uid, ['sudoPassword']);
   if len(res) != 1:
      raise Error, "Not exactly one hit when searching for user"
   if res[0][1].has_key('sudoPassword'):
      inldap = res[0][1]['sudoPassword']
   else:
      inldap = []

   newldap = []
   for entry in inldap:
      Match = re.compile('^('+UUID_FORMAT+') (confirmed:[0-9a-f]{40}|unconfirmed) ([a-z0-9.,*]+) ([^ ]+)$').match(entry)
      if Match == None:
         raise Error, "Could not parse existing sudopasswd entry"
      uuid = Match.group(1)
      status = Match.group(2)
      hosts = Match.group(3)
      cryptedpass = Match.group(4)

      if SudoPasswd.has_key(uuid):
         confirmedHosts = SudoPasswd[uuid][0]
         confirmedHmac = SudoPasswd[uuid][1]
         if status.startswith('confirmed:'):
            if status == 'confirmed:'+make_passwd_hmac('password-is-confirmed', 'sudo', uid, uuid, hosts, cryptedpass):
               result = result + "Entry %s for sudo password on hosts %s already confirmed.\n"%(uuid, hosts)
            else:
               result = result + "Entry %s for sudo password on hosts %s is listed as confirmed, but HMAC does not verify.\n"%(uuid, hosts)
         elif confirmedHosts != hosts:
            result = result + "Entry %s hostlist mismatch (%s vs. %s).\n"%(uuid, hosts, confirmedHosts)
         elif make_passwd_hmac('confirm-new-password', 'sudo', uid, uuid, hosts, cryptedpass) == confirmedHmac:
            result = result + "Entry %s for sudo password on hosts %s now confirmed.\n"%(uuid, hosts)
            status = 'confirmed:'+make_passwd_hmac('password-is-confirmed', 'sudo', uid, uuid, hosts, cryptedpass)
         else:
            result = result + "Entry %s for sudo password on hosts %s HMAC verify failed.\n"%(uuid, hosts)
         del SudoPasswd[uuid]

      newentry = " ".join([uuid, status, hosts, cryptedpass])
      if len(newldap) == 0:
         newldap.append((ldap.MOD_REPLACE,"sudoPassword",newentry))
      else:
         newldap.append((ldap.MOD_ADD,"sudoPassword",newentry))

   for entry in SudoPasswd:
      result = result + "Entry %s that you confirm is not listed in ldap."%(entry)

   for entry in newldap:
      Attrs.append(entry)

   return result

# Handle an [almost] arbitary change
def HandleChange(Reply,DnRecord,Key):
   global PlainText;
   Lines = re.split("\n *\r?",PlainText);

   Result = "";
   Attrs = [];
   Show = 0;
   CommitChanges = 1
   for Line in Lines: 
      Line = Line.strip()
      if Line == "":
         continue;

      # Try to process a command line
      Result = Result + "> "+Line+"\n";
      try:
         if Line == "show":
            Show = 1;
            Res = "OK";
         else:
            badkeys = LoadBadSSH()
            Res = DoPosition(Line,Attrs) or DoDNS(Line,Attrs,DnRecord) or \
                  DoArbChange(Line,Attrs) or DoSSH(Line,Attrs,badkeys,GetAttr(DnRecord,"uid")) or \
                  DoDel(Line,Attrs) or DoRBL(Line,Attrs) or DoConfirmSudopassword(Line)
      except:
         Res = None;
         Result = Result + "==> %s: %s\n" %(sys.exc_type,sys.exc_value);

      # Fail, if someone tries to send someone elses signed email to the
      # daemon then we want to abort ASAP.
      if Res == None:
         CommitChanges = 0
         Result = Result + "Command is not understood. Halted - no changes committed\n";
         break;
      Result = Result + Res + "\n";

   # Connect to the ldap server
   l = connectLDAP()
   F = open(PassDir+"/pass-"+pwd.getpwuid(os.getuid())[0],"r");
   AccessPass = F.readline().strip().split(" ")
   F.close();

   l.simple_bind_s("uid="+AccessPass[0]+","+BaseDn,AccessPass[1]);
   oldAttrs = l.search_s(BaseDn,ldap.SCOPE_ONELEVEL,"uid="+GetAttr(DnRecord,"uid"));
   if ((GetAttr(oldAttrs[0],"userPassword").find("*LK*") != -1) 
       or GetAttr(oldAttrs[0],"userPassword").startswith("!")):
      raise Error, "This account is locked";
   try:
      Res = FinishConfirmSudopassword(l, GetAttr(DnRecord,"uid"), Attrs)
      Result = Result + Res + "\n";
   except Error, e:
      CommitChanges = 0
      Result = Result + "FinishConfirmSudopassword raised an error (%s) - no changes committed\n"%(e);
   # Modify the record
   Dn = "uid=" + GetAttr(DnRecord,"uid") + "," + BaseDn;
   if CommitChanges == 1:
      l.modify_s(Dn,Attrs);

   Attribs = "";
   if Show == 1:
      Attrs = l.search_s(BaseDn,ldap.SCOPE_ONELEVEL,"uid="+GetAttr(DnRecord,"uid"));
      if len(Attrs) == 0:
         raise Error, "User not found"
      Attribs = GPGEncrypt(PrettyShow(Attrs[0])+"\n","0x"+Key[1],Key[4]);
      
   Subst = {};
   Subst["__FROM__"] = ChangeFrom;
   Subst["__EMAIL__"] = EmailAddress(DnRecord);
   Subst["__ADMIN__"] = ReplyTo;
   Subst["__RESULT__"] = Result;
   Subst["__ATTR__"] = Attribs;

   return Reply + TemplateSubst(Subst,open(TemplatesDir+"change-reply","r").read());
   
# Handle ping handles an email sent to the 'ping' address (ie this program
# called with a ping argument) It replies with a dump of the public records.
def HandlePing(Reply,DnRecord,Key):
   Subst = {};
   Subst["__FROM__"] = PingFrom;
   Subst["__EMAIL__"] = EmailAddress(DnRecord);
   Subst["__LDAPFIELDS__"] = PrettyShow(DnRecord);
   Subst["__ADMIN__"] = ReplyTo;

   return Reply + TemplateSubst(Subst,open(TemplatesDir+"ping-reply","r").read());

# Handle a change password email sent to the change password address
# (this program called with the chpass argument)
def HandleChPass(Reply,DnRecord,Key):
   # Generate a random password
   Password = GenPass();
   Pass = HashPass(Password);
      
   # Use GPG to encrypt it      
   Message = GPGEncrypt("Your new password is '" + Password + "'\n",\
                        "0x"+Key[1],Key[4]);
   Password = None;

   if Message == None:
      raise Error, "Unable to generate the encrypted reply, gpg failed.";

   if (Key[4] == 1):
      Type = "Your message was encrypted using PGP 2.x\ncompatibility mode.";
   else:
      Type = "Your message was encrypted using GPG (OpenPGP)\ncompatibility "\
             "mode, without IDEA. This message cannot be decoded using PGP 2.x";
   
   Subst = {};
   Subst["__FROM__"] = ChPassFrom;
   Subst["__EMAIL__"] = EmailAddress(DnRecord);
   Subst["__CRYPTTYPE__"] = Type;
   Subst["__PASSWORD__"] = Message;
   Subst["__ADMIN__"] = ReplyTo;
   Reply = Reply + TemplateSubst(Subst,open(TemplatesDir+"passwd-changed","r").read());
   
   # Connect to the ldap server
   l = connectLDAP()
   F = open(PassDir+"/pass-"+pwd.getpwuid(os.getuid())[0],"r");
   AccessPass = F.readline().strip().split(" ")
   F.close();
   l.simple_bind_s("uid="+AccessPass[0]+","+BaseDn,AccessPass[1]);

   # Check for a locked account
   Attrs = l.search_s(BaseDn,ldap.SCOPE_ONELEVEL,"uid="+GetAttr(DnRecord,"uid"));
   if (GetAttr(Attrs[0],"userPassword").find("*LK*") != -1) \
             or GetAttr(Attrs[0],"userPassword").startswith("!"):
      raise Error, "This account is locked";

   # Modify the password
   Rec = [(ldap.MOD_REPLACE,"userPassword","{crypt}"+Pass),
          (ldap.MOD_REPLACE,"shadowLastChange",str(int(time.time()/24/60/60)))];
   Dn = "uid=" + GetAttr(DnRecord,"uid") + "," + BaseDn;
   l.modify_s(Dn,Rec);

   return Reply;
      
# Start of main program

# Drop messages from a mailer daemon.
if os.environ.has_key('SENDER') == 0 or len(os.environ['SENDER']) == 0:
   sys.exit(0);

ErrMsg = "Indeterminate Error";
ErrType = EX_TEMPFAIL;
try:
   # Startup the replay cache
   ErrType = EX_TEMPFAIL;
   ErrMsg = "Failed to initialize the replay cache:";
   RC = ReplayCache(ReplayCacheFile);
   RC.Clean();

   # Get the email 
   ErrType = EX_PERMFAIL;
   ErrMsg = "Failed to understand the email or find a signature:";
   Email = mimetools.Message(sys.stdin,0);
   Msg = GetClearSig(Email);

   ErrMsg = "Message is not PGP signed:"
   if Msg[0].find("-----BEGIN PGP SIGNED MESSAGE-----") == -1 and \
      Msg[0].find("-----BEGIN PGP MESSAGE-----") == -1:
      raise Error, "No PGP signature";
   
   # Check the signature
   ErrMsg = "Unable to check the signature or the signature was invalid:";
   Res = GPGCheckSig(Msg[0]);

   if Res[0] != None:
      raise Error, Res[0];
      
   if Res[3] == None:
      raise Error, "Null signature text";

   # Extract the plain message text in the event of mime encoding
   global PlainText;
   ErrMsg = "Problem stripping MIME headers from the decoded message"
   if Msg[1] == 1:
      try:
         Index = Res[3].index("\n\n") + 2;
      except ValueError:
         Index = Res[3].index("\n\r\n") + 3;
      PlainText = Res[3][Index:];
   else:
      PlainText = Res[3];   

   # Check the signature against the replay cache
   ErrMsg = "The replay cache rejected your message. Check your clock!";
   Rply = RC.Check(Res[1]);
   if Rply != None:
      raise Error, Rply;

   # Connect to the ldap server
   ErrType = EX_TEMPFAIL;
   ErrMsg = "An error occured while performing the LDAP lookup";
   global l;
   l = connectLDAP()
   l.simple_bind_s("","");

   # Search for the matching key fingerprint
   Attrs = l.search_s(BaseDn,ldap.SCOPE_ONELEVEL,"keyFingerPrint=" + Res[2][1]);

   ErrType = EX_PERMFAIL;
   if len(Attrs) == 0:
      raise Error, "Key not found"
   if len(Attrs) != 1:
      raise Error, "Oddly your key fingerprint is assigned to more than one account.."

   RC.Add(Res[1]);

   # Determine the sender address
   ErrMsg = "A problem occured while trying to formulate the reply";
   Sender = Email.getheader("Reply-To");
   if Sender == None:
      Sender = Email.getheader("From");
   if Sender == None:
      raise Error, "Unable to determine the sender's address";

   # Formulate a reply
   Date = time.strftime("%a, %d %b %Y %H:%M:%S +0000",time.gmtime(time.time()));
   Reply = "To: %s\nReply-To: %s\nDate: %s\n" % (Sender,ReplyTo,Date);

   # Dispatch
   if sys.argv[1] == "ping":
      Reply = HandlePing(Reply,Attrs[0],Res[2]);
   elif sys.argv[1] == "chpass":
      if PlainText.strip().find("Please change my Debian password") != 0:
         raise Error,"Please send a signed message where the first line of text is the string 'Please change my Debian password'";
      Reply = HandleChPass(Reply,Attrs[0],Res[2]);
   elif sys.argv[1] == "change":
      Reply = HandleChange(Reply,Attrs[0],Res[2]);
   else:
      print sys.argv;
      raise Error, "Incorrect Invokation";

   # Send the message through sendmail      
   ErrMsg = "A problem occured while trying to send the reply";
   Child = os.popen("/usr/sbin/sendmail -t","w");
#   Child = os.popen("cat","w");
   Child.write(Reply);
   if Child.close() != None:
      raise Error, "Sendmail gave a non-zero return code";

except:
   # Error Reply Header
   Date = time.strftime("%a, %d %b %Y %H:%M:%S +0000",time.gmtime(time.time()));
   ErrReplyHead = "To: %s\nReply-To: %s\nDate: %s\n" % (os.environ['SENDER'],ReplyTo,Date);

   # Error Body
   Subst = {};
   Subst["__ERROR__"] = ErrMsg;
   Subst["__ADMIN__"] = ReplyTo;

   Trace = "==> %s: %s\n" %(sys.exc_type,sys.exc_value);
   List = traceback.extract_tb(sys.exc_traceback);
   if len(List) > 1:
      Trace = Trace + "Python Stack Trace:\n";
      for x in List:
         Trace = Trace +  "   %s %s:%u: %s\n" %(x[2],x[0],x[1],x[3]);

   Subst["__TRACE__"] = Trace;

   # Try to send the bounce
   try:
      ErrReply = TemplateSubst(Subst,open(TemplatesDir+"error-reply","r").read());

      Child = os.popen("/usr/sbin/sendmail -t","w");
      Child.write(ErrReplyHead);
      Child.write(ErrReply);
      if Child.close() != None:
         raise Error, "Sendmail gave a non-zero return code";
   except:
      sys.exit(EX_TEMPFAIL);
      
   if ErrType != EX_PERMFAIL:
      sys.exit(ErrType);
   sys.exit(0);