Signed-off-by: Balazs Lecz <[email protected]>
---
lib/serializer.py | 30 ++++++++++++++++++++++++++----
test/ganeti.serializer_unittest.py | 10 +++++++++-
2 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/lib/serializer.py b/lib/serializer.py
index b568497..314a934 100644
--- a/lib/serializer.py
+++ b/lib/serializer.py
@@ -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
diff --git a/test/ganeti.serializer_unittest.py
b/test/ganeti.serializer_unittest.py
index 11a60e6..22ecc41 100755
--- a/test/ganeti.serializer_unittest.py
+++ b/test/ganeti.serializer_unittest.py
@@ -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")
--
1.6.6.2
