Commit 72ca1dcb authored by Balazs Lecz's avatar Balazs Lecz Committed by Michael Hanselmann

Add multi-key support to the serializer

Signed-off-by: default avatarBalazs Lecz <leczb@google.com>
Reviewed-by: default avatarMichael Hanselmann <hansmi@google.com>
parent 9e289e36
......@@ -101,11 +101,13 @@ def LoadJson(txt):
return simplejson.loads(txt)
def DumpSignedJson(data, key, salt=None):
def DumpSignedJson(data, key, salt=None, key_selector=None):
"""Serialize a given object and authenticate it.
@param data: the data to serialize
@param key: shared hmac key
@param key_selector: name/id that identifies the key (in case there are
multiple keys in use, e.g. in a multi-cluster environment)
@return: the string representation of data signed by the hmac key
"""
......@@ -115,8 +117,15 @@ def DumpSignedJson(data, key, salt=None):
signed_dict = {
'msg': txt,
'salt': salt,
'hmac': hmac.new(key, salt + txt, sha1).hexdigest(),
}
if key_selector:
signed_dict["key_selector"] = key_selector
message = salt + key_selector + txt
else:
message = salt + txt
signed_dict["hmac"] = hmac.new(key, message,
sha1).hexdigest()
return DumpJson(signed_dict, indent=False)
......@@ -124,7 +133,9 @@ def LoadSignedJson(txt, key):
"""Verify that a given message was signed with the given key, and load it.
@param txt: json-encoded hmac-signed message
@param key: shared hmac key
@param key: the shared hmac key or a callable taking one argument (the key
selector), which returns the hmac key belonging to the key selector.
Typical usage is to pass a reference to the get method of a dict.
@rtype: tuple of original data, string
@return: original data, salt
@raises errors.SignatureError: if the message signature doesn't verify
......@@ -140,7 +151,18 @@ def LoadSignedJson(txt, key):
except KeyError:
raise errors.SignatureError('Invalid external message')
if hmac.new(key, salt + msg, sha1).hexdigest() != hmac_sign:
if callable(key):
key_selector = signed_dict.get("key_selector", None)
hmac_key = key(key_selector)
if not hmac_key:
raise errors.SignatureError("No key with key selector '%s' found" %
key_selector)
else:
key_selector = ""
hmac_key = key
if hmac.new(hmac_key, salt + key_selector + msg,
sha1).hexdigest() != hmac_sign:
raise errors.SignatureError('Invalid Signature')
return LoadJson(msg), salt
......
......@@ -71,10 +71,18 @@ class TestSerializer(testutils.GanetiTestCase):
self.assertEqualValues(LoadSigned(DumpSigned(data, "mykey"), "mykey"),
(data, ''))
self.assertEqualValues(LoadSigned(DumpSigned(data, "myprivatekey",
"mysalt"),
salt="mysalt"),
"myprivatekey"),
(data, "mysalt"))
keydict = {"mykey_id": "myprivatekey"}
self.assertEqualValues(LoadSigned(DumpSigned(data,
"myprivatekey",
salt="mysalt",
key_selector="mykey_id"),
keydict.get),
(data, "mysalt"))
self.assertRaises(errors.SignatureError, serializer.LoadSigned,
serializer.DumpSigned("test", "myprivatekey"),
"myotherkey")
......
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