root / lib / serializer.py @ ed008420
History | View | Annotate | Download (3.1 kB)
1 |
#
|
---|---|
2 |
#
|
3 |
|
4 |
# Copyright (C) 2007, 2008 Google Inc.
|
5 |
#
|
6 |
# This program is free software; you can redistribute it and/or modify
|
7 |
# it under the terms of the GNU General Public License as published by
|
8 |
# the Free Software Foundation; either version 2 of the License, or
|
9 |
# (at your option) any later version.
|
10 |
#
|
11 |
# This program is distributed in the hope that it will be useful, but
|
12 |
# WITHOUT ANY WARRANTY; without even the implied warranty of
|
13 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
14 |
# General Public License for more details.
|
15 |
#
|
16 |
# You should have received a copy of the GNU General Public License
|
17 |
# along with this program; if not, write to the Free Software
|
18 |
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
19 |
# 02110-1301, USA.
|
20 |
|
21 |
"""Serializer abstraction module
|
22 |
|
23 |
This module introduces a simple abstraction over the serialization
|
24 |
backend (currently json).
|
25 |
|
26 |
"""
|
27 |
|
28 |
import simplejson |
29 |
import re |
30 |
import hmac |
31 |
|
32 |
from ganeti import errors |
33 |
|
34 |
try:
|
35 |
from hashlib import sha1 |
36 |
except ImportError: |
37 |
import sha as sha1 |
38 |
|
39 |
# Check whether the simplejson module supports indentation
|
40 |
_JSON_INDENT = 2
|
41 |
try:
|
42 |
simplejson.dumps(1, indent=_JSON_INDENT)
|
43 |
except TypeError: |
44 |
_JSON_INDENT = None
|
45 |
|
46 |
_RE_EOLSP = re.compile('[ \t]+$', re.MULTILINE)
|
47 |
|
48 |
|
49 |
def DumpJson(data, indent=True): |
50 |
"""Serialize a given object.
|
51 |
|
52 |
@param data: the data to serialize
|
53 |
@param indent: whether to indent output (depends on simplejson version)
|
54 |
|
55 |
@return: the string representation of data
|
56 |
|
57 |
"""
|
58 |
if not indent or _JSON_INDENT is None: |
59 |
txt = simplejson.dumps(data) |
60 |
else:
|
61 |
txt = simplejson.dumps(data, indent=_JSON_INDENT) |
62 |
|
63 |
txt = _RE_EOLSP.sub("", txt)
|
64 |
if not txt.endswith('\n'): |
65 |
txt += '\n'
|
66 |
return txt
|
67 |
|
68 |
|
69 |
def LoadJson(txt): |
70 |
"""Unserialize data from a string.
|
71 |
|
72 |
@param txt: the json-encoded form
|
73 |
|
74 |
@return: the original data
|
75 |
|
76 |
"""
|
77 |
return simplejson.loads(txt)
|
78 |
|
79 |
|
80 |
def DumpSignedJson(data, key, salt=None): |
81 |
"""Serialize a given object and authenticate it.
|
82 |
|
83 |
@param data: the data to serialize
|
84 |
@param key: shared hmac key
|
85 |
@return: the string representation of data signed by the hmac key
|
86 |
|
87 |
"""
|
88 |
txt = DumpJson(data, indent=False)
|
89 |
if salt is None: |
90 |
salt = ''
|
91 |
signed_dict = { |
92 |
'msg': txt,
|
93 |
'salt': salt,
|
94 |
'hmac': hmac.new(key, salt + txt, sha1).hexdigest(),
|
95 |
} |
96 |
return DumpJson(signed_dict, indent=False) |
97 |
|
98 |
|
99 |
def LoadSignedJson(txt, key): |
100 |
"""Verify that a given message was signed with the given key, and load it.
|
101 |
|
102 |
@param txt: json-encoded hmac-signed message
|
103 |
@param key: shared hmac key
|
104 |
@rtype: tuple of original data, string
|
105 |
@return: original data, salt
|
106 |
@raises errors.SignatureError: if the message signature doesn't verify
|
107 |
|
108 |
"""
|
109 |
signed_dict = LoadJson(txt) |
110 |
if not isinstance(signed_dict, dict): |
111 |
raise errors.SignatureError('Invalid external message') |
112 |
try:
|
113 |
msg = signed_dict['msg']
|
114 |
salt = signed_dict['salt']
|
115 |
hmac_sign = signed_dict['hmac']
|
116 |
except KeyError: |
117 |
raise errors.SignatureError('Invalid external message') |
118 |
|
119 |
if hmac.new(key, salt + msg, sha1).hexdigest() != hmac_sign:
|
120 |
raise errors.SignatureError('Invalid Signature') |
121 |
|
122 |
return LoadJson(msg), salt
|
123 |
|
124 |
|
125 |
Dump = DumpJson |
126 |
Load = LoadJson |
127 |
DumpSigned = DumpSignedJson |
128 |
LoadSigned = LoadSignedJson |