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as2lib.py
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as2lib.py
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import requests
import email.Message
import email.utils
import hashlib
import as2utils
import os
import base64
from django.utils.translation import ugettext as _
from email.mime.multipart import MIMEMultipart
from email.parser import HeaderParser
from M2Crypto import BIO, Rand, SMIME, X509
from pyas2 import models
from pyas2 import pyas2init
from string import Template
def save_message(message, raw_payload):
''' Function decompresses, decrypts and verifies the received message'''
try:
payload = email.message_from_string(raw_payload)
micContent = None
models.Log.objects.create(message=message, status='S', text=_(u'Begin Processing of received AS2 message'))
if not models.Organization.objects.filter(as2_name=as2utils.unescape_as2name(payload.get('as2-to'))).exists():
raise as2utils.as2partnernotfound('Unknown AS2 organization with id %s'%payload.get('as2-to'))
message.organization = models.Organization.objects.get(as2_name=as2utils.unescape_as2name(payload.get('as2-to')))
if not models.Partner.objects.filter(as2_name=as2utils.unescape_as2name(payload.get('as2-from'))).exists():
raise as2utils.as2partnernotfound('Unknown AS2 Trading partner with id %s'%payload.get('as2-from'))
message.partner = models.Partner.objects.get(as2_name=as2utils.unescape_as2name(payload.get('as2-from')))
models.Log.objects.create(
message=message,
status='S',
text=_(u'Message is for Organization "%s" from partner "%s"'%(message.organization, message.partner))
)
#micContent = payload.get_payload()
filename = payload.get_filename()
if message.partner.encryption and payload.get_content_type() != 'application/pkcs7-mime':
raise as2utils.as2insufficientsecurity('Incoming messages from AS2 partner %s are defined to be encrypted'%message.partner.as2_name)
if payload.get_content_type() == 'application/pkcs7-mime' and payload.get_param('smime-type') == 'enveloped-data':
models.Log.objects.create(message=message, status='S', text=_(u'Decrypting the payload using private key %s'%message.organization.encryption_key))
message.encrypted = True
### Check if data is base64, if not then encode
try:
payload.get_payload().encode('ascii')
except Exception,e:
payload.set_payload(payload.get_payload().encode('base64'))
pyas2init.logger.debug('Decrypting the payload :\n%s'%payload.get_payload())
try:
decrypted_content = as2utils.decrypt_payload(
as2utils.mimetostring(payload,78),
str(message.organization.encryption_key.certificate.path),
str(message.organization.encryption_key.certificate_passphrase)
)
#micContent,raw_payload = as2utils.canonicalize(decrypted_content),decrypted_content
raw_payload = decrypted_content
payload = email.message_from_string(decrypted_content)
### Check if decrypted content is the actual content
if payload.get_content_type() == 'text/plain':
payload = email.Message.Message()
payload.set_payload(decrypted_content)
payload.set_type('application/edi-consent')
if filename:
payload.add_header('Content-Disposition', 'attachment', filename=filename)
except Exception, msg:
raise as2utils.as2decryptionfailed('Failed to decrypt message, exception message is %s' %msg)
if message.partner.signature and payload.get_content_type() != 'multipart/signed':
raise as2utils.as2insufficientsecurity('Incoming messages from AS2 partner %s are defined to be signed'%message.partner.as2_name)
if payload.get_content_type() == 'multipart/signed':
if not message.partner.signature_key:
raise as2utils.as2insufficientsecurity('Partner has no signature verification key defined')
micalg = payload.get_param('micalg').lower() or 'sha1'
models.Log.objects.create(message=message, status='S', text=_(u'Message is signed, Verifying it using public key %s'%message.partner.signature_key))
pyas2init.logger.debug('Verifying the signed payload:\n%s'%payload.as_string())
message.signed = True
main_boundary = '--' + payload.get_boundary()
cert = str(message.partner.signature_key.certificate.path)
ca_cert = cert
if message.partner.signature_key.ca_cert:
ca_cert = str(message.partner.signature_key.ca_cert.path)
verify_cert = message.partner.signature_key.verify_cert
### Extract the base64 encoded signature
for part in payload.walk():
if part.get_content_type() == "application/pkcs7-signature":
try:
raw_sig = part.get_payload().encode('ascii').strip()
except Exception,e:
raw_sig = part.get_payload().encode('base64').strip()
else:
payload = part
### Verify message using complete raw payload received from partner
try:
as2utils.verify_payload(as2utils.canonicalize2(payload),raw_sig,cert,ca_cert,verify_cert)
except Exception, e:
### Verify message using extracted signature and stripped message
try:
as2utils.verify_payload(as2utils.extractpayload_fromstring1(raw_payload,main_boundary),raw_sig,cert,ca_cert,verify_cert)
except Exception, e:
### Verify message using extracted signature and message without extra trailing new line
try:
as2utils.verify_payload(as2utils.extractpayload_fromstring2(raw_payload,main_boundary),raw_sig,cert,ca_cert,verify_cert)
except Exception, e:
raise as2utils.as2invalidsignature('Signature Verification Failed, exception message is %s'%str(e))
micContent = as2utils.canonicalize2(payload)
#micContent = as2utils.extractpayload_fromstring2(raw_payload,main_boundary)
if payload.get_content_type() == 'application/pkcs7-mime' and payload.get_param('smime-type') == 'compressed-data':
models.Log.objects.create(message=message, status='S', text=_(u'Decompressing the payload'))
message.compressed = True
### Decode the data if its base64
try:
payload.get_payload().encode('ascii')
cdata = base64.b64decode(payload.get_payload())
except Exception,e:
cdata = payload.get_payload()
pyas2init.logger.debug('Decompressing the payload:\n%s'%cdata)
try:
dcontent = as2utils.decompress_payload(cdata)
#if not message.signed :
#micContent = as2utils.canonicalize(dcontent)
payload = email.message_from_string(dcontent)
except Exception, e:
raise as2utils.as2decompressionfailed('Failed to decompress message,exception message is %s' %e)
### Saving the message mic for sending it in the MDN
if micContent:
pyas2init.logger.debug("Calcualting MIC with alg %s for content:\n%s"%(micalg,micContent))
calcMIC = getattr(hashlib, micalg.replace('-',''), hashlib.sha1)
message.mic = '%s, %s'%(calcMIC(micContent).digest().encode('base64').strip(), micalg)
return payload
finally:
message.save()
def build_mdn(message, status, **kwargs):
''' Function builds AS2 MDN report '''
try:
hparser = HeaderParser()
message_header = hparser.parsestr(message.headers)
text = _(u'The AS2 message has been processed. Thank you for exchanging AS2 messages with Pyas2.')
if status != 'success':
#### Send mail here
as2utils.senderrorreport(message, _(u'Failure in processing message from partner,\n Basic status : %s \n Advanced Status: %s'%(kwargs['adv_status'],kwargs['status_message'])))
text = _(u'The AS2 message could not be processed. The disposition-notification report has additional details.')
models.Log.objects.create(message=message, status='E', text = kwargs['status_message'])
message.status = 'E'
else:
message.status = 'S'
if not message_header.get('disposition-notification-to'):
models.Log.objects.create(message=message, status='S', text=_(u'MDN not requested by partner, closing request.'))
return None, None
models.Log.objects.create(message=message, status='S', text=_(u'Building the MDN response to the request'))
main = MIMEMultipart('report', report_type="disposition-notification")
textmessage = email.Message.Message()
textmessage.set_payload("%s\n"%text)
textmessage.set_type('text/plain')
textmessage.set_charset('us-ascii')
del textmessage['MIME-Version']
main.attach(textmessage)
mdnbase = email.Message.Message()
mdnbase.set_type('message/disposition-notification')
mdnbase.set_charset('us-ascii')
mdn = 'Reporting-UA: Bots Opensource EDI Translator\n'
mdn = mdn + 'Original-Recipient: rfc822; %s\n'%message_header.get('as2-to')
mdn = mdn + 'Final-Recipient: rfc822; %s\n'%message_header.get('as2-to')
mdn = mdn + 'Original-Message-ID: <%s>\n'%message.message_id
if status != 'success':
mdn = mdn + 'Disposition: automatic-action/MDN-sent-automatically; processed/%s: %s\n'%(status, kwargs['adv_status'])
else:
mdn = mdn + 'Disposition: automatic-action/MDN-sent-automatically; processed\n'
if message.mic:
mdn = mdn + 'Received-content-MIC: %s\n'%message.mic
mdnbase.set_payload(mdn)
del mdnbase['MIME-Version']
main.attach(mdnbase)
del main['MIME-Version']
pyas2init.logger.debug('MDN for message %s created:\n%s'%(message.message_id,main.as_string()))
mdnsigned = False
if message_header.get('disposition-notification-options') and message.organization and message.organization.signature_key:
models.Log.objects.create(message=message, status='S', text=_(u'Signing the MDN using private key %s'%message.organization.signature_key))
mdnsigned = True
options = message_header.get('disposition-notification-options').split(";")
algorithm = options[1].split(",")[1].strip()
signed = MIMEMultipart('signed', protocol="application/pkcs7-signature")
signed.attach(main)
micalg, signature = as2utils.sign_payload(
as2utils.canonicalize(as2utils.mimetostring(main, 0)+'\n'),
str(message.organization.signature_key.certificate.path),
str(message.organization.signature_key.certificate_passphrase)
)
pyas2init.logger.debug('Signature for MDN created:\n%s'%signature.as_string())
signed.set_param('micalg',micalg)
signed.attach(signature)
mdnmessage = signed
else:
mdnmessage = main
### Add new line between the MDN message and the signature
mdnbody = as2utils.extractpayload(mdnmessage)
mainboundary = '--' + main.get_boundary() + '--'
mdnbody = as2utils.canonicalize(mdnbody.replace(mainboundary, mainboundary + '\n'))
mdnmessage.add_header('ediint-features', 'CEM')
mdnmessage.add_header('as2-from', message_header.get('as2-to'))
mdnmessage.add_header('as2-to', message_header.get('as2-from'))
mdnmessage.add_header('AS2-Version', '1.2')
mdnmessage.add_header('date', email.Utils.formatdate(localtime=True))
mdnmessage.add_header('Message-ID', email.utils.make_msgid())
mdnmessage.add_header('user-agent', 'PYAS2, A pythonic AS2 server')
filename = mdnmessage.get('message-id').strip('<>') + '.mdn'
fullfilename = as2utils.storefile(pyas2init.gsettings['mdn_send_store'],filename,mdnbody,True)
mdn_headers = ''
for key in mdnmessage.keys():
mdn_headers = mdn_headers + '%s: %s\n'%(key, mdnmessage[key])
if message_header.get('receipt-delivery-option'):
message.mdn = models.MDN.objects.create(message_id=filename, file=fullfilename, status='P', signed=mdnsigned, headers=mdn_headers, return_url= message_header['receipt-delivery-option'])
message.mdn_mode = 'ASYNC'
mdnbody, mdnmessage = None, None
models.Log.objects.create(message=message, status='S', text=_(u'Asynchronous MDN requested, setting status to pending'))
else:
message.mdn = models.MDN.objects.create(message_id=filename,file=fullfilename, status='S', signed=mdnsigned, headers=mdn_headers)
message.mdn_mode = 'SYNC'
models.Log.objects.create(message=message, status='S', text=_(u'MDN created successfully and sent to partner'))
return mdnbody, mdnmessage
finally:
message.save()
def build_message(message):
''' Build the AS2 mime message to be sent to partner'''
models.Log.objects.create(message=message, status='S', text=_(u'Build the AS2 message and header to send to the partner'))
reference = '<%s>'%message.message_id
micContent = None
email_datetime = email.Utils.formatdate(localtime=True)
as2Header = {
'AS2-Version' : '1.2',
'ediint-features' : 'CEM',
'MIME-Version' : '1.0',
'Message-ID' : reference,
'AS2-From' : as2utils.escape_as2name(message.organization.as2_name),
'AS2-To' : as2utils.escape_as2name(message.partner.as2_name),
'Subject' : message.partner.subject,
'Date' : email_datetime,
'recipient-address' : message.partner.target_url,
'user-agent' : 'PYAS2, A pythonic AS2 server'
}
payload = email.Message.Message()
with open(message.payload.file, 'rb') as fh:
payload.set_payload(fh.read())
fh.close()
payload.set_type(message.partner.content_type)
payload.add_header('Content-Disposition', 'attachment', filename=message.payload.name)
del payload['MIME-Version']
#micContent,cmicContent,content = payload.get_payload(),None,payload.get_payload()
content = payload.get_payload()
if message.partner.compress:
models.Log.objects.create(message=message, status='S', text=_(u'Compressing the payload.'))
message.compressed = True
#micContent = as2utils.canonicalize(as2utils.mimetostring(payload, 0))
cmessage = email.Message.Message()
cmessage.set_type('application/pkcs7-mime')
cmessage.set_param('name', 'smime.p7z')
cmessage.set_param('smime-type', 'compressed-data')
cmessage.add_header('Content-Transfer-Encoding', 'base64')
cmessage.add_header('Content-Disposition', 'attachment', filename='smime.p7z')
cmessage.set_payload(as2utils.compress_payload(as2utils.canonicalize(as2utils.mimetostring(payload, 0))))
content,payload = cmessage.get_payload(),cmessage
pyas2init.logger.debug('Compressed message %s payload as:\n%s'%(message.message_id,payload.as_string()))
if message.partner.signature:
models.Log.objects.create(message=message, status='S', text=_(u'Signing the message using organzation key %s'%message.organization.signature_key))
message.signed = True
multipart = MIMEMultipart('signed',protocol="application/pkcs7-signature")
del multipart['MIME-Version']
#micContent = as2utils.canonicalize2(payload)
micContent = as2utils.canonicalize(as2utils.mimetostring(payload, 0))
multipart.attach(payload)
micalg, signature = as2utils.sign_payload(micContent, str(message.organization.signature_key.certificate.path), str(message.organization.signature_key.certificate_passphrase))
multipart.set_param('micalg',micalg)
multipart.attach(signature)
multipart.as_string()
content = as2utils.canonicalize(as2utils.extractpayload(multipart))
payload = multipart
pyas2init.logger.debug('Signed message %s payload as:\n%s'%(message.message_id,payload.as_string()))
if message.partner.encryption:
#if not message.compressed and not message.signed:
#micContent = as2utils.canonicalize(as2utils.mimetostring(payload, 0))
models.Log.objects.create(message=message, status='S', text=_(u'Encrypting the message using partner key %s'%message.partner.encryption_key))
message.encrypted = True
payload = as2utils.encrypt_payload(as2utils.canonicalize(as2utils.mimetostring(payload, 0)), message.partner.encryption_key.certificate.path , message.partner.encryption)
payload.set_type('application/pkcs7-mime')
content = payload.get_payload()
pyas2init.logger.debug('Encrypted message %s payload as:\n%s'%(message.message_id,payload.as_string()))
if message.partner.mdn:
as2Header['disposition-notification-to'] = 'no-reply@pyas2.com'
if message.partner.mdn_sign:
as2Header['disposition-notification-options'] = 'signed-receipt-protocol=required, pkcs7-signature; signed-receipt-micalg=optional, %s'%message.partner.mdn_sign
message.mdn_mode = 'SYNC'
if message.partner.mdn_mode == 'ASYNC':
as2Header['receipt-delivery-option'] = pyas2init.gsettings['mdn_url']
message.mdn_mode = 'ASYNC'
if micContent:
pyas2init.logger.debug("Calcualting MIC with alg %s for content:\n%s"%(micalg,micContent))
calcMIC = getattr(hashlib, micalg.replace('-',''), hashlib.sha1)
message.mic = calcMIC(micContent).digest().encode('base64').strip()
as2Header.update(payload.items())
message.headers = ''
for key in as2Header:
message.headers = message.headers + '%s: %s\n'%(key, as2Header[key])
message.save()
models.Log.objects.create(message=message, status='S', text=_(u'AS2 message has been built successfully, sending it to the partner'))
return content
def send_message(message, payload):
''' Sends the AS2 message to the partner '''
try:
hparser = HeaderParser()
message_header = hparser.parsestr(message.headers)
auth = None
if message.partner.http_auth:
auth = (message.partner.http_auth_user, message.partner.http_auth_pass)
verify = True
if message.partner.https_ca_cert:
verify = message.partner.https_ca_cert.path
try:
response = requests.post(message.partner.target_url, auth = auth, verify=verify, headers = dict(message_header.items()), data = payload)
response.raise_for_status()
except Exception,e:
### Send mail here
as2utils.senderrorreport(message, _(u'Failure during transmission of message to partner with error "%s".\n\nTo retry transmission run the management command "retryfailedas2comms".'%e))
message.status = 'R'
models.Log.objects.create(message=message, status='E', text=_(u'Message send failed with error %s'%e))
return
models.Log.objects.create(message=message, status='S', text=_(u'AS2 message successfully sent to partner'))
if message.partner.mdn:
if message.partner.mdn_mode == 'ASYNC':
models.Log.objects.create(message=message, status='S', text=_(u'Requested ASYNC MDN from partner, waiting for it ........'))
message.status = 'P'
return
mdnContent = '';
for key in response.headers:
mdnContent = mdnContent + '%s: %s\n'%(key, response.headers[key])
mdnContent = mdnContent + '\n' + response.content
models.Log.objects.create(message=message, status='S', text=_(u'Synchronous mdn received from partner'))
pyas2init.logger.debug('Synchronus MDN from message %s received:\n%s'%(message.message_id,mdnContent))
save_mdn(message, mdnContent)
else:
message.status = 'S'
models.Log.objects.create(message=message, status='S', text=_(u'No MDN needed, File Transferred successfully to the partner'))
run_postsend(message)
finally:
message.save()
def save_mdn(message, mdnContent):
''' Process the received MDN and check status of sent message '''
try:
mdnMessage = email.message_from_string(mdnContent)
mdnHeaders = ''
for key in mdnMessage.keys():
mdnHeaders = mdnHeaders + '%s: %s\n'%(key, mdnMessage[key])
messageId = mdnMessage.get('message-id')
if message.partner.mdn_sign and mdnMessage.get_content_type() != 'multipart/signed':
models.Log.objects.create(message=message, status='W', text=_(u'Expected signed MDN but unsigned MDN returned'))
mdnsigned = False
if mdnMessage.get_content_type() == 'multipart/signed':
models.Log.objects.create(message=message, status='S', text=_(u'Verifying the signed MDN with partner key %s'%message.partner.signature_key))
mdnsigned = True
cert = str(message.partner.signature_key.certificate.path)
ca_cert = cert
if message.partner.signature_key.ca_cert:
ca_cert = str(message.partner.signature_key.ca_cert.path)
verify_cert = message.partner.signature_key.verify_cert
main_boundary = '--' + mdnMessage.get_boundary()
### Extract the mssage and signature
for part in mdnMessage.get_payload():
if part.get_content_type().lower() == "application/pkcs7-signature":
sig = part
else:
mdnMessage = part
### check if signature is base64 encoded and if not encode
try:
raw_sig = sig.get_payload().encode('ascii').strip()
except Exception,e:
raw_sig = sig.get_payload().encode('base64').strip()
### Verify the signature using raw contents
try:
as2utils.verify_payload(mdnContent,None,cert,ca_cert,verify_cert)
except Exception, e:
### Verify the signature using extracted signature and message
try:
as2utils.verify_payload(as2utils.extractpayload_fromstring1(mdnContent,main_boundary),raw_sig,cert,ca_cert,verify_cert)
except Exception, e:
### Verify the signature using extracted signature and message without extra trailing new line in message
try:
as2utils.verify_payload(as2utils.extractpayload_fromstring2(mdnContent,main_boundary),raw_sig,cert,ca_cert,verify_cert)
except Exception, e:
raise as2utils.as2exception(_(u'MDN Signature Verification Error, exception message is %s' %e))
filename = messageId.strip('<>') + '.mdn'
fullfilename = as2utils.storefile(pyas2init.gsettings['mdn_receive_store'],filename,as2utils.extractpayload(mdnMessage),True)
message.mdn = models.MDN.objects.create(message_id=messageId.strip('<>'),file=fullfilename, status='R', headers=mdnHeaders, signed=mdnsigned)
if mdnMessage.get_content_type() == 'multipart/report':
for part in mdnMessage.walk():
if (part.get_content_type() == 'message/disposition-notification'):
pyas2init.logger.debug('Found MDN report for message %s:\n%s'%(message.message_id,part.as_string()))
models.Log.objects.create(message=message, status='S', text=_(u'Checking the MDN for status of the message'))
mdn = part.get_payload().pop()
mdnOMessageId = mdn.get('Original-Message-ID')
mdnStatus = mdn.get('Disposition').split(';')
if (mdnStatus[1].strip() == 'processed'):
models.Log.objects.create(message=message, status='S', text=_(u'Message has been successfully processed, verifying the MIC if present.'))
if mdn.get('Received-Content-MIC') and message.mic:
mdnMIC = mdn.get('Received-Content-MIC').split(',');
if (message.mic != mdnMIC[0]):
message.status = 'W'
models.Log.objects.create(message=message, status='W', text=_(u'Message Integrity check failed, please validate message content with your partner'))
else:
message.status = 'S'
models.Log.objects.create(message=message, status='S', text=_(u'File Transferred successfully to the partner'))
else:
message.status = 'S'
models.Log.objects.create(message=message, status='S', text=_(u'File Transferred successfully to the partner'))
run_postsend(message)
else:
raise as2utils.as2exception(_(u'Partner failed to process file. MDN status is %s'%mdn.get('Disposition')))
else:
raise as2utils.as2exception(_(u'MDN report not found in the response'))
finally:
message.save()
def run_postsend(message):
''' Execute command after successful send, can be used to notify successfule sends '''
command = message.partner.cmd_send
if command:
models.Log.objects.create(message=message, status='S', text=_(u'Exectute command post successful send'))
command = Template(command)
variables = {'filename':message.payload.name, 'sender':message.organization.as2_name, 'recevier':message.partner.as2_name, 'messageid':message.message_id}
variables.update(dict(HeaderParser().parsestr(message.headers).items()))
os.system(command.safe_substitute(variables))
def run_postreceive(message,fullfilename):
''' Execute command after successful receive, can be used to call the edi program for further processing'''
command = message.partner.cmd_receive
if command:
models.Log.objects.create(message=message, status='S', text=_(u'Exectute command post successful receive'))
command = Template(command)
variables = {'filename':message.payload.name, 'fullfilename':fullfilename, 'sender':message.organization.as2_name, 'recevier':message.partner.as2_name, 'messageid':message.message_id}
variables.update(dict(HeaderParser().parsestr(message.headers).items()))
os.system(command.safe_substitute(variables))