1 Introduction
2 ------------
3
4 MoinMessage provides a library for creating, signing, encrypting, decrypting,
5 and verifying PGP/GPG content in Python along with mechanisms for updating
6 MoinMoin Wiki instances with such content such that contributors can be
7 identified from their PGP signatures and such details used to authenticate
8 their contributions.
9
10 Configuring GPG for a Wiki
11 --------------------------
12
13 Initialise a homedir for GPG and configure it using filesystem ACL (access
14 control list) properties:
15
16 ./scripts/init_wiki_keyring.sh WIKI WEBUSER
17
18 Here, WIKI should be replaced by the top-level Wiki instance directory, and
19 WEBUSER should be the name of the user under which the Web server operates.
20
21 Note that this script may need re-running after the homedir has been changed
22 by gpg operations as gpg likes to remove permissions from various files.
23
24 To be in any way useful, signing keys must be made available within this
25 homedir so that incoming messages can have their senders verified.
26
27 To see the keys available to you in your own environment:
28
29 gpg --list-keys --with-fingerprint
30
31 The full fingerprints are used when defining a user mapping in the Wiki, and
32 the --with-fingerprint option is used to show them. Otherwise, only the last
33 eight characters of the fingerprints are shown.
34
35 Export the public key used when signing messages from your own environment:
36
37 gpg --armor --output 1C1AAF83.asc --export 1C1AAF83
38
39 Import the key into the Wiki's GPG homedir:
40
41 gpg --homedir wiki/gnupg --import 1C1AAF83.asc
42
43 For the Wiki to receive encrypted data, a key for the Wiki must be created:
44
45 gpg --homedir wiki/gnupg --gen-key
46
47 For the Wiki environment to be able to use the key, password access must be
48 disabled. This can be done by either not specifying a password or by removing
49 it later using the --edit-key option.
50
51 Export the Wiki's key for encrypting messages sent to the Wiki:
52
53 gpg --homedir wiki/gnupg --armor --output 0891463A.asc --export 0891463A
54
55 This exported key can now be imported into your own environment:
56
57 gpg --import 0891463A.asc
58
59 Configuring the Wiki
60 --------------------
61
62 In the Wiki configuration, define the following settings:
63
64 moinmessage_gpg_homedir
65 This sets the path to the homedir initialised above.
66
67 moinmessage_gpg_users_page (optional, default is MoinMessageUserDict)
68 This provides a mapping from key fingerprints to Moin usernames.
69
70 moinmessage_gpg_signing_users_page (optional, default is MoinMessageSigningUserDict)
71 This provides a mapping from Moin usernames to key fingerprints.
72
73 moinmessage_gpg_recipients_page (optional, default is MoinMessageRecipientsDict)
74 This provides a mapping from recipients to remote URLs and key fingerprints.
75 Each user can define the named page as a subpage of their own home page.
76 If no such personal mapping exists, a common mapping exists relative to the
77 site root.
78
79 moinmessage_reject_messages_without_dates (optional, default is True)
80 This causes messages sent to a Wiki using the PostMessage action to be
81 rejected if date information is missing.
82
83 moinmessage_static_files (optional, may refer to the built-in htdocs directory)
84 This explicitly defines the path to static resources used by Moin, enabling
85 such resources to be attached to messages. When set, the path must refer to
86 the htdocs directory (possibly renamed) containing the different theme
87 resource directories, together with the robots.txt and favicon.ico files.)
88
89 For signature verification to function, the following needs to be added:
90
91 from MoinMoin.auth.pgp import PGPAuth
92
93 This should import an authentication handler installed when the MoinMessage
94 software is installed as an extension package.
95
96 Within the configuration class itself, the auth setting needs to be updated to
97 include PGPAuth in the list of registered handlers. For example:
98
99 auth = [MoinAuth(), PGPAuth()]
100
101 This would permit the traditional Moin authentication and add signature-based
102 authentication so that messages can be accepted by the Wiki.
103
104 Fingerprints and Keys
105 ---------------------
106
107 All fingerprints mentioned in the various configuration pages must exclude
108 space characters - that is, the letters and digits must appear together in a
109 continuous block of text - and refer to keys available in the Wiki homedir.
110
111 The Fingerprint-to-Username Mapping
112 -----------------------------------
113
114 The mapping from fingerprints to usernames typically defined by the
115 MoinMessageUserDict page is a WikiDict having the following general format:
116
117 fingerprint:: username
118
119 Each fingerprint corresponds to a key used by a person wanting to send
120 messages to the Wiki to sign such messages.
121
122 Each username must correspond to a registered user in the Wiki.
123
124 The Username-to-Signing Key Mapping
125 -----------------------------------
126
127 The mapping from usernames to fingerprints typically defined by the
128 MoinMessageSigningUserDict page is a WikiDict having the following general
129 format:
130
131 username:: fingerprint
132
133 Each fingerprint corresponds to a key available in the Wiki's GPG homedir
134 generated for the purpose of signing the specified user's messages. Such a key
135 is not the same as one used by a person to send messages to the Wiki since
136 only the public key used to verify such messages should be known to the Wiki.
137
138 The Recipients Mapping
139 ----------------------
140
141 The mapping from recipients to remote URLs and fingerprints typically defined
142 by the MoinMessageRecipientsDict page is a WikiDict having the following
143 general format:
144
145 recipient:: type location [ fingerprint ]
146
147 Where the type is "page", the accompanying location must be a page name
148 indicating a page that provides a message store that will accept messages.
149
150 Where the type is "url", the accompanying location must be a URL that must
151 itself refer to a resource that can accept MoinMessage content.
152
153 Where a type of "url" has been given, a fingerprint must accompany this
154 information in order to encrypt messages sent to the specified resource.
155
156 Each fingerprint corresponds to a key used by the Wiki to encrypt messages and
157 by the remote site (as identified by the URL) to decrypt messages.
158
159 Quick Start: Signing, Encrypting and Sending Messages
160 -----------------------------------------------------
161
162 To send a message signed and encrypted to a resource on localhost:
163
164 python tests/test_send.py 1C1AAF83 0891463A http://localhost/wiki/ShareTest \
165 collection update 'An update to the Wiki.' 'Another update.'
166
167 Here, the first identifier is a reference to the signing key (over which you
168 have complete control), and the second identifier is a reference to the
169 encryption key (which is a public key published for the Wiki).
170
171 This needs password protection to be removed from the secret key in the Web
172 server environment. It also uses a modified trust model when invoking gpg in
173 order to avoid complaints about the identity of the sender during encryption.
174
175 To sign the encrypted message for forwarding, the above command is modified:
176
177 python tests/test_send.py 1C1AAF83 0891463A --forward 1C1AAF83 \
178 http://localhost/wiki/ShareTest \
179 collection update 'An update to the Wiki.' 'Another update.'
180
181 Below, the mechanisms employed are illustrated through the use of the other
182 test programs.
183
184 Signing
185 -------
186
187 Prepare a message signed with a "detached signature" (note that this does not
188 seem to be what gpg calls a detached signature with the --detach-sig option):
189
190 python tests/test_message.py collection update 'An update to the Wiki.' \
191 'Another update.' \
192 | python tests/test_sign.py 1C1AAF83
193
194 The complicated recipe based on the individual operations is as follows:
195
196 python tests/test_message.py collection update 'An update to the Wiki.' \
197 'Another update.' \
198 > test.txt \
199 && cat test.txt \
200 | gpg --armor -u 1C1AAF83 --detach-sig \
201 | python tests/test_sign_wrap.py test.txt
202
203 Encryption
204 ----------
205
206 Prepare a message with an encrypted payload using the above key:
207
208 python tests/test_message.py collection update 'An update to the Wiki.' \
209 'Another update.' \
210 | python tests/test_encrypt.py 0891463A
211
212 The complicated recipe based on the individual operations is as follows:
213
214 python tests/test_message.py collection update 'An update to the Wiki.' \
215 'Another update.' \
216 > test.txt \
217 && cat test.txt \
218 | gpg --armor -r 0891463A --encrypt --trust-model always \
219 | python tests/test_encrypt_wrap.py
220
221 Note that "--trust-model always" is used only to avoid prompting issues.
222
223 Signing and Encrypting
224 ----------------------
225
226 Sign and encrypt a message:
227
228 python tests/test_message.py collection update 'An update to the Wiki.' \
229 'Another update.' \
230 | python tests/test_sign.py 1C1AAF83 \
231 | python tests/test_encrypt.py 0891463A
232
233 The complicated recipe based on the individual operations is as follows:
234
235 python tests/test_message.py collection update 'An update to the Wiki.' \
236 'Another update.' \
237 > test.txt \
238 && cat test.txt \
239 | gpg --armor -u 1C1AAF83 --detach-sig \
240 | python tests/test_sign_wrap.py test.txt \
241 | gpg --armor -r 0891463A --encrypt --trust-model always \
242 | python tests/test_encrypt_wrap.py
243
244 Signing and Encrypting then Signing
245 -----------------------------------
246
247 Where a message is to be forwarded and not decrypted, it will be signed by the
248 author, encrypted, but then signed by the forwarder (perhaps initially the
249 author):
250
251 python tests/test_message.py collection update 'An update to the Wiki.' \
252 'Another update.' \
253 | python tests/test_sign.py 1C1AAF83 \
254 | python tests/test_encrypt.py 0891463A \
255 | python tests/test_sign.py 1C1AAF83
256
257 The complicated recipe based on the individual operations is as follows:
258
259 python tests/test_message.py collection update 'An update to the Wiki.' \
260 'Another update.' \
261 > test.txt \
262 && cat test.txt \
263 | gpg --armor -u 1C1AAF83 --detach-sig \
264 | python tests/test_sign_wrap.py test.txt \
265 | gpg --armor -r 0891463A --encrypt --trust-model always \
266 | python tests/test_encrypt_wrap.py \
267 > test2.txt \
268 && cat test2.txt \
269 | gpg --armor -u 1C1AAF83 --detach-sig \
270 | python tests/test_sign_wrap.py test2.txt
271
272 Posting a Message
273 -----------------
274
275 To post a signed and/or encrypted message, output from the above activities
276 can be piped into the following command:
277
278 python tests/test_post.py http://localhost/wiki/ShareTest
279
280 Here, the resource "/wiki/ShareTest" on localhost is presented with the
281 message.
282
283 Fetching Messages
284 -----------------
285
286 To fetch messages from a message store associated with a page, the following
287 command can be used:
288
289 python tests/test_fetch.py 1C1AAF83 0891463A http://localhost/wiki/ShareTest \
290 RETR
291
292 This should retrieve all messages from the store associated with the
293 "/wiki/ShareTest" resource on localhost.
294
295 The Message Format
296 ------------------
297
298 Messages are MIME-encoded and consist of one or more update fragments. Where
299 the "Update-Type" header is present and set to a value of "collection", a
300 multipart message describes as many updates as there are parts. Otherwise,
301 only a single update is described by the message.
302
303 For each update, the "Update-Action" header indicates the action to be taken
304 with the update content. Where it is absent, the content is inserted into the
305 Wiki page specified in the request; where it is present and set to "replace",
306 the content replaces all content on the Wiki page; where it is set to "store",
307 the content is stored in a message store associated with the Wiki page.
308
309 Each update may describe multiple representations of some content by employing
310 a multipart/alternative section containing parts for each of the
311 representations. Alternatively, a single message part may describe a single
312 representation.
313
314 HTTP Methods
315 ------------
316
317 Since MoinMoin seems to reserve POST methods for request/entity bodies that
318 contain HTML form data, it is necessary to use alternative methods to post
319 messages to a site served by MoinMoin and to fetch messages from such a site.
320 Consequently, MoinMessage uses PUT to post messages and recommends GET to
321 fetch messages.