def user_login(request):
username=request.POST['username']
password=request.POST['password']
metadata=request.POST['metadata']
# authenticate the user
user = authenticate(username=username, password=password)
if user is not None and user.is_active:
# Authentication worked -- now for the metadata
try:
metadata = UserMeta.objects.get(owner=user)
except ObjectDoesNotExist:
# This shouldn't happen. fail
return HttpResponse(status=500)
md_aes = AES.new(aes_secret_padding(password), AES.MODE_CFB)
md_ptext = md_aes.decrypt(metadata.data)
# perform cyclic redundancy check
# crc should be the first 4 chars of plaintext. slice it off...
crc, md_ptext = (md_ptext[-4:], md_ptext[:-4])
if not crc == struct.pack('i', zlib.crc32(md_ptext)):
# CRC failed. Metadata is bonked
# TODO: recover from this error without giving the attacker a way
# to break in.
return HttpResponse(status=500)
# Now we can use the metadata to validate the user
md_new = json.loads(metadata)
md_extant = json.loads(md_plaintext)
md_valid = validate_user_metadata(md_new, md_extant)
if md_valid is not None:
# Update metadata and reencrypt it
md_aes = AES.new(aes_secret_padding(password), AES.MODE_CFB)
metadata.data = md_aes.encrypt(json.dumps({
'keystrokes': md_valid['ks'],
'variance' : md_valid['variance']
}))
# persist this data to the DB
metadata.save()
# login is seperate from authentication -- it's almost as if the
# creators of Django know what they're doing...
login(request, user)
return HttpResponse(status=200)
# VERBOTEN
return HttpResponse(status=403)
# Load data into correct format for the first time
md_list = json.loads(request.POST['metadata'])
metadata = json.dumps({
'keystrokes': md_list
'variance' : [0 for _ in md_list]
})
# Create the user
user = User.objects.create(
username=username,
password=password
)
# IMPORTANT -- Encrypt the metadata with AES using
# the password as a key so that the attacker doesn't get the key length
md_aes = AES.new(aes_secret_padding(password), AES.MODE_CFB)
md_cipher = md_aes.encrypt(metadata)
user_md = UserMeta.objects.create(
owner=user,
data=md_cipher
)
user.save()
user_md.save()
return HttpResponse(status=200)
def user_login(request):
username=request.POST['username']
password=request.POST['password']
metadata=request.POST['metadata']
# authenticate the user
