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-rw-r--r--filters/gentoo-ldap-authentication.lua320
1 files changed, 320 insertions, 0 deletions
diff --git a/filters/gentoo-ldap-authentication.lua b/filters/gentoo-ldap-authentication.lua new file mode 100644 index 0000000..fce5632 --- /dev/null +++ b/filters/gentoo-ldap-authentication.lua
@@ -0,0 +1,320 @@
1-- This script may be used with the auth-filter. Be sure to configure it as you wish.
2--
3-- Requirements:
4-- luacrypto >= 0.3
5-- <http://mkottman.github.io/luacrypto/>
6-- lualdap >= 1.2
7-- <http://git.zx2c4.com/lualdap/about/>
8--
9
10
11--
12--
13-- Configure these variables for your settings.
14--
15--
16
17-- A list of password protected repositories, with which gentooAccess
18-- group is allowed to access each one.
19local protected_repos = {
20 glouglou = "infra",
21 portage = "dev"
22}
23
24
25-- All cookies will be authenticated based on this secret. Make it something
26-- totally random and impossible to guess. It should be large.
27local secret = "BE SURE TO CUSTOMIZE THIS STRING TO SOMETHING BIG AND RANDOM"
28
29
30
31--
32--
33-- Authentication functions follow below. Swap these out if you want different authentication semantics.
34--
35--
36
37-- Sets HTTP cookie headers based on post and sets up redirection.
38function authenticate_post()
39 local redirect = validate_value("redirect", post["redirect"])
40
41 if redirect == nil then
42 not_found()
43 return 0
44 end
45
46 redirect_to(redirect)
47
48 local groups = gentoo_ldap_user_groups(post["username"], post["password"])
49 if groups == nil then
50 set_cookie("cgitauth", "")
51 else
52 -- One week expiration time
53 set_cookie("cgitauth", secure_value("gentoogroups", table.concat(groups, ","), os.time() + 604800))
54 end
55
56 html("\n")
57 return 0
58end
59
60
61-- Returns 1 if the cookie is valid and 0 if it is not.
62function authenticate_cookie()
63 local required_group = protected_repos[cgit["repo"]]
64 if required_group == nil then
65 -- We return as valid if the repo is not protected.
66 return 1
67 end
68
69 local user_groups = validate_value("gentoogroups", get_cookie(http["cookie"], "cgitauth"))
70 if user_groups == nil or user_groups == "" then
71 return 0
72 end
73 for group in string.gmatch(user_groups, "[^,]+") do
74 if group == required_group then
75 return 1
76 end
77 end
78 return 0
79end
80
81-- Prints the html for the login form.
82function body()
83 html("<h2>Gentoo LDAP Authentication Required</h2>")
84 html("<form method='post' action='")
85 html_attr(cgit["login"])
86 html("'>")
87 html("<input type='hidden' name='redirect' value='")
88 html_attr(secure_value("redirect", cgit["url"], 0))
89 html("' />")
90 html("<table>")
91 html("<tr><td><label for='username'>Username:</label></td><td><input id='username' name='username' autofocus /></td></tr>")
92 html("<tr><td><label for='password'>Password:</label></td><td><input id='password' name='password' type='password' /></td></tr>")
93 html("<tr><td colspan='2'><input value='Login' type='submit' /></td></tr>")
94 html("</table></form>")
95
96 return 0
97end
98
99--
100--
101-- Gentoo LDAP support.
102--
103--
104
105local lualdap = require("lualdap")
106
107function gentoo_ldap_user_groups(username, password)
108 -- Ensure the user is alphanumeric
109 if username:match("%W") then
110 return nil
111 end
112
113 local who = "uid=" .. username .. ",ou=devs,dc=gentoo,dc=org"
114
115 local ldap, err = lualdap.open_simple {
116 uri = "ldap://ldap1.gentoo.org",
117 who = who,
118 password = password,
119 starttls = true,
120 certfile = "/var/www/uwsgi/cgit/gentoo-ldap/star.gentoo.org.crt",
121 keyfile = "/var/www/uwsgi/cgit/gentoo-ldap/star.gentoo.org.key",
122 cacertfile = "/var/www/uwsgi/cgit/gentoo-ldap/ca.pem"
123 }
124 if ldap == nil then
125 return nil
126 end
127
128 local group_suffix = ".group"
129 local group_suffix_len = group_suffix:len()
130 local groups = {}
131 for dn, attribs in ldap:search { base = who, scope = "subtree" } do
132 local access = attribs["gentooAccess"]
133 if dn == who and access ~= nil then
134 for i, v in ipairs(access) do
135 local vlen = v:len()
136 if vlen > group_suffix_len and v:sub(-group_suffix_len) == group_suffix then
137 table.insert(groups, v:sub(1, vlen - group_suffix_len))
138 end
139 end
140 end
141 end
142
143 ldap:close()
144
145 return groups
146end
147
148--
149--
150-- Wrapper around filter API, exposing the http table, the cgit table, and the post table to the above functions.
151--
152--
153
154local actions = {}
155actions["authenticate-post"] = authenticate_post
156actions["authenticate-cookie"] = authenticate_cookie
157actions["body"] = body
158
159function filter_open(...)
160 action = actions[select(1, ...)]
161
162 http = {}
163 http["cookie"] = select(2, ...)
164 http["method"] = select(3, ...)
165 http["query"] = select(4, ...)
166 http["referer"] = select(5, ...)
167 http["path"] = select(6, ...)
168 http["host"] = select(7, ...)
169 http["https"] = select(8, ...)
170
171 cgit = {}
172 cgit["repo"] = select(9, ...)
173 cgit["page"] = select(10, ...)
174 cgit["url"] = select(11, ...)
175 cgit["login"] = select(12, ...)
176
177end
178
179function filter_close()
180 return action()
181end
182
183function filter_write(str)
184 post = parse_qs(str)
185end
186
187
188--
189--
190-- Utility functions based on keplerproject/wsapi.
191--
192--
193
194function url_decode(str)
195 if not str then
196 return ""
197 end
198 str = string.gsub(str, "+", " ")
199 str = string.gsub(str, "%%(%x%x)", function(h) return string.char(tonumber(h, 16)) end)
200 str = string.gsub(str, "\r\n", "\n")
201 return str
202end
203
204function url_encode(str)
205 if not str then
206 return ""
207 end
208 str = string.gsub(str, "\n", "\r\n")
209 str = string.gsub(str, "([^%w ])", function(c) return string.format("%%%02X", string.byte(c)) end)
210 str = string.gsub(str, " ", "+")
211 return str
212end
213
214function parse_qs(qs)
215 local tab = {}
216 for key, val in string.gmatch(qs, "([^&=]+)=([^&=]*)&?") do
217 tab[url_decode(key)] = url_decode(val)
218 end
219 return tab
220end
221
222function get_cookie(cookies, name)
223 cookies = string.gsub(";" .. cookies .. ";", "%s*;%s*", ";")
224 return string.match(cookies, ";" .. name .. "=(.-);")
225end
226
227
228--
229--
230-- Cookie construction and validation helpers.
231--
232--
233
234local crypto = require("crypto")
235
236-- Returns value of cookie if cookie is valid. Otherwise returns nil.
237function validate_value(expected_field, cookie)
238 local i = 0
239 local value = ""
240 local field = ""
241 local expiration = 0
242 local salt = ""
243 local hmac = ""
244
245 if cookie == nil or cookie:len() < 3 or cookie:sub(1, 1) == "|" then
246 return nil
247 end
248
249 for component in string.gmatch(cookie, "[^|]+") do
250 if i == 0 then
251 field = component
252 elseif i == 1 then
253 value = component
254 elseif i == 2 then
255 expiration = tonumber(component)
256 if expiration == nil then
257 expiration = -1
258 end
259 elseif i == 3 then
260 salt = component
261 elseif i == 4 then
262 hmac = component
263 else
264 break
265 end
266 i = i + 1
267 end
268
269 if hmac == nil or hmac:len() == 0 then
270 return nil
271 end
272
273 -- Lua hashes strings, so these comparisons are time invariant.
274 if hmac ~= crypto.hmac.digest("sha1", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
275 return nil
276 end
277
278 if expiration == -1 or (expiration ~= 0 and expiration <= os.time()) then
279 return nil
280 end
281
282 if url_decode(field) ~= expected_field then
283 return nil
284 end
285
286 return url_decode(value)
287end
288
289function secure_value(field, value, expiration)
290 if value == nil or value:len() <= 0 then
291 return ""
292 end
293
294 local authstr = ""
295 local salt = crypto.hex(crypto.rand.bytes(16))
296 value = url_encode(value)
297 field = url_encode(field)
298 authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
299 authstr = authstr .. "|" .. crypto.hmac.digest("sha1", authstr, secret)
300 return authstr
301end
302
303function set_cookie(cookie, value)
304 html("Set-Cookie: " .. cookie .. "=" .. value .. "; HttpOnly")
305 if http["https"] == "yes" or http["https"] == "on" or http["https"] == "1" then
306 html("; secure")
307 end
308 html("\n")
309end
310
311function redirect_to(url)
312 html("Status: 302 Redirect\n")
313 html("Cache-Control: no-cache, no-store\n")
314 html("Location: " .. url .. "\n")
315end
316
317function not_found()
318 html("Status: 404 Not Found\n")
319 html("Cache-Control: no-cache, no-store\n\n")
320end