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1 | /* modules/m_sasl.c | |
2 | * Copyright (C) 2006 Michael Tharp <gxti@partiallystapled.com> | |
3 | * Copyright (C) 2006 charybdis development team | |
4 | * Copyright (C) 2016 ChatLounge IRC Network Development Team | |
5 | * | |
6 | * Redistribution and use in source and binary forms, with or without | |
7 | * modification, are permitted provided that the following conditions are | |
8 | * met: | |
9 | * | |
10 | * 1.Redistributions of source code must retain the above copyright notice, | |
11 | * this list of conditions and the following disclaimer. | |
12 | * 2.Redistributions in binary form must reproduce the above copyright | |
13 | * notice, this list of conditions and the following disclaimer in the | |
14 | * documentation and/or other materials provided with the distribution. | |
15 | * 3.The name of the author may not be used to endorse or promote products | |
16 | * derived from this software without specific prior written permission. | |
17 | * | |
18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED | |
20 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | |
21 | * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, | |
22 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | |
23 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR | |
24 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
25 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
26 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING | |
27 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
28 | * POSSIBILITY OF SUCH DAMAGE. | |
29 | */ | |
30 | ||
31 | #include "stdinc.h" | |
32 | ||
33 | #include "client.h" | |
34 | #include "hash.h" | |
35 | #include "send.h" | |
36 | #include "msg.h" | |
37 | #include "modules.h" | |
38 | #include "numeric.h" | |
39 | #include "reject.h" | |
40 | #include "s_serv.h" | |
41 | #include "s_stats.h" | |
42 | #include "string.h" | |
43 | #include "s_newconf.h" | |
44 | #include "s_conf.h" | |
45 | ||
46 | static const char sasl_desc[] = "Provides SASL authentication support"; | |
47 | ||
48 | static void m_authenticate(struct MsgBuf *, struct Client *, struct Client *, int, const char **); | |
49 | static void me_sasl(struct MsgBuf *, struct Client *, struct Client *, int, const char **); | |
50 | static void me_mechlist(struct MsgBuf *, struct Client *, struct Client *, int, const char **); | |
51 | ||
52 | static void abort_sasl(void *); | |
53 | static void abort_sasl_exit(void *); | |
54 | ||
55 | static unsigned int CLICAP_SASL = 0; | |
56 | static char mechlist_buf[BUFSIZE]; | |
57 | ||
58 | struct Message authenticate_msgtab = { | |
59 | "AUTHENTICATE", 0, 0, 0, 0, | |
60 | {{m_authenticate, 2}, {m_authenticate, 2}, mg_ignore, mg_ignore, mg_ignore, {m_authenticate, 2}} | |
61 | }; | |
62 | struct Message sasl_msgtab = { | |
63 | "SASL", 0, 0, 0, 0, | |
64 | {mg_ignore, mg_ignore, mg_ignore, mg_ignore, {me_sasl, 5}, mg_ignore} | |
65 | }; | |
66 | struct Message mechlist_msgtab = { | |
67 | "MECHLIST", 0, 0, 0, 0, | |
68 | {mg_ignore, mg_ignore, mg_ignore, mg_ignore, {me_mechlist, 2}, mg_ignore} | |
69 | }; | |
70 | ||
71 | mapi_clist_av1 sasl_clist[] = { | |
72 | &authenticate_msgtab, &sasl_msgtab, &mechlist_msgtab, NULL | |
73 | }; | |
74 | mapi_hfn_list_av1 sasl_hfnlist[] = { | |
75 | { "client_exit", abort_sasl_exit }, | |
76 | { NULL, NULL } | |
77 | }; | |
78 | ||
79 | static const char * | |
80 | sasl_data(struct Client *client_p) | |
81 | { | |
82 | return *mechlist_buf != 0 ? mechlist_buf : NULL; | |
83 | } | |
84 | ||
85 | static struct ClientCapability capdata_sasl = { | |
86 | .data = sasl_data, | |
87 | .flags = CLICAP_FLAGS_STICKY | CLICAP_FLAGS_PRIORITY, | |
88 | }; | |
89 | ||
90 | mapi_cap_list_av2 sasl_cap_list[] = { | |
91 | { MAPI_CAP_CLIENT, "sasl", &capdata_sasl, &CLICAP_SASL }, | |
92 | { 0, NULL, NULL, NULL }, | |
93 | }; | |
94 | ||
95 | static int | |
96 | _modinit(void) | |
97 | { | |
98 | memset(mechlist_buf, 0, sizeof mechlist_buf); | |
99 | return 0; | |
100 | } | |
101 | ||
102 | DECLARE_MODULE_AV2(sasl, _modinit, NULL, sasl_clist, NULL, sasl_hfnlist, sasl_cap_list, NULL, sasl_desc); | |
103 | ||
104 | static void | |
105 | m_authenticate(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, | |
106 | int parc, const char *parv[]) | |
107 | { | |
108 | struct Client *agent_p = NULL; | |
109 | struct Client *saslserv_p = NULL; | |
110 | ||
111 | /* They really should use CAP for their own sake. */ | |
112 | if(!IsCapable(source_p, CLICAP_SASL)) | |
113 | return; | |
114 | ||
115 | if(source_p->localClient->sasl_next_retry > rb_current_time()) | |
116 | { | |
117 | sendto_one(source_p, form_str(RPL_LOAD2HI), me.name, EmptyString(source_p->name) ? "*" : source_p->name, msgbuf_p->cmd); | |
118 | return; | |
119 | } | |
120 | ||
121 | if (strlen(client_p->id) == 3 || (source_p->preClient && !EmptyString(source_p->preClient->id))) | |
122 | { | |
123 | exit_client(client_p, client_p, client_p, "Mixing client and server protocol"); | |
124 | return; | |
125 | } | |
126 | ||
127 | if (*parv[1] == ':' || strchr(parv[1], ' ')) | |
128 | { | |
129 | exit_client(client_p, client_p, client_p, "Malformed AUTHENTICATE"); | |
130 | return; | |
131 | } | |
132 | ||
133 | saslserv_p = find_named_client(ConfigFileEntry.sasl_service); | |
134 | if(saslserv_p == NULL || !IsService(saslserv_p)) | |
135 | { | |
136 | sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name); | |
137 | return; | |
138 | } | |
139 | ||
140 | if(source_p->localClient->sasl_complete) | |
141 | { | |
142 | *source_p->localClient->sasl_agent = '\0'; | |
143 | source_p->localClient->sasl_complete = 0; | |
144 | } | |
145 | ||
146 | if(strlen(parv[1]) > 400) | |
147 | { | |
148 | sendto_one(source_p, form_str(ERR_SASLTOOLONG), me.name, EmptyString(source_p->name) ? "*" : source_p->name); | |
149 | return; | |
150 | } | |
151 | ||
152 | if(!*source_p->id) | |
153 | { | |
154 | /* Allocate a UID. */ | |
155 | rb_strlcpy(source_p->id, generate_uid(), sizeof(source_p->id)); | |
156 | add_to_id_hash(source_p->id, source_p); | |
157 | } | |
158 | ||
159 | if(*source_p->localClient->sasl_agent) | |
160 | agent_p = find_id(source_p->localClient->sasl_agent); | |
161 | ||
162 | if(agent_p == NULL) | |
163 | { | |
164 | if (!strcmp(parv[1], "*")) | |
165 | { | |
166 | sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name); | |
167 | source_p->localClient->sasl_out = 0; | |
168 | return; | |
169 | } | |
170 | ||
171 | sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s H %s %s %c", | |
172 | me.id, saslserv_p->servptr->name, source_p->id, saslserv_p->id, | |
173 | source_p->host, source_p->sockhost, | |
174 | IsSecure(source_p) ? 'S' : 'P'); | |
175 | ||
176 | if (source_p->certfp != NULL) | |
177 | sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s S %s %s", | |
178 | me.id, saslserv_p->servptr->name, source_p->id, saslserv_p->id, | |
179 | parv[1], source_p->certfp); | |
180 | else | |
181 | sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s S %s", | |
182 | me.id, saslserv_p->servptr->name, source_p->id, saslserv_p->id, | |
183 | parv[1]); | |
184 | ||
185 | rb_strlcpy(source_p->localClient->sasl_agent, saslserv_p->id, IDLEN); | |
186 | } | |
187 | else | |
188 | { | |
189 | if (!strcmp(parv[1], "*")) | |
190 | { | |
191 | sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name); | |
192 | sendto_one(agent_p, ":%s ENCAP %s SASL %s %s D A", me.id, agent_p->servptr->name, source_p->id, agent_p->id); | |
193 | source_p->localClient->sasl_out = 0; | |
194 | return; | |
195 | } | |
196 | ||
197 | sendto_one(agent_p, ":%s ENCAP %s SASL %s %s C %s", | |
198 | me.id, agent_p->servptr->name, source_p->id, agent_p->id, | |
199 | parv[1]); | |
200 | } | |
201 | ||
202 | source_p->localClient->sasl_out++; | |
203 | } | |
204 | ||
205 | static void | |
206 | me_sasl(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, | |
207 | int parc, const char *parv[]) | |
208 | { | |
209 | struct Client *target_p, *agent_p; | |
210 | bool in_progress; | |
211 | ||
212 | /* Let propagate if not addressed to us, or if broadcast. | |
213 | * Only SASL agents can answer global requests. | |
214 | */ | |
215 | if(strncmp(parv[2], me.id, 3)) | |
216 | return; | |
217 | ||
218 | if((target_p = find_id(parv[2])) == NULL) | |
219 | return; | |
220 | ||
221 | if((agent_p = find_id(parv[1])) == NULL) | |
222 | return; | |
223 | ||
224 | if(source_p != agent_p->servptr) /* WTF?! */ | |
225 | return; | |
226 | ||
227 | /* We only accept messages from SASL agents; these must have umode +S | |
228 | * (so the server must be listed in a service{} block). | |
229 | */ | |
230 | if(!IsService(agent_p)) | |
231 | return; | |
232 | ||
233 | /* If SASL has been aborted, we only want to track authentication failures. */ | |
234 | in_progress = target_p->localClient->sasl_out != 0; | |
235 | ||
236 | /* Reject if someone has already answered. */ | |
237 | if(*target_p->localClient->sasl_agent && strncmp(parv[1], target_p->localClient->sasl_agent, IDLEN)) | |
238 | return; | |
239 | else if(!*target_p->localClient->sasl_agent && in_progress) | |
240 | rb_strlcpy(target_p->localClient->sasl_agent, parv[1], IDLEN); | |
241 | ||
242 | if(*parv[3] == 'C') | |
243 | { | |
244 | if (in_progress) { | |
245 | sendto_one(target_p, "AUTHENTICATE %s", parv[4]); | |
246 | target_p->localClient->sasl_messages++; | |
247 | } | |
248 | } | |
249 | else if(*parv[3] == 'D') | |
250 | { | |
251 | if(*parv[4] == 'F') | |
252 | { | |
253 | if (in_progress) { | |
254 | sendto_one(target_p, form_str(ERR_SASLFAIL), me.name, EmptyString(target_p->name) ? "*" : target_p->name); | |
255 | } | |
256 | /* Failures with zero messages are just "unknown mechanism" errors; don't count those. */ | |
257 | if(target_p->localClient->sasl_messages > 0) | |
258 | { | |
259 | if(*target_p->name) | |
260 | { | |
261 | /* Allow 2 tries before rate-limiting as some clients try EXTERNAL | |
262 | * then PLAIN right after it if the auth failed, causing the client to be | |
263 | * rate-limited immediately and not being able to login with SASL. | |
264 | */ | |
265 | if (target_p->localClient->sasl_failures++ > 0) | |
266 | target_p->localClient->sasl_next_retry = rb_current_time() + (1 << MIN(target_p->localClient->sasl_failures + 1, 8)); | |
267 | } | |
268 | else if(throttle_add((struct sockaddr*)&target_p->localClient->ip)) | |
269 | { | |
270 | exit_client(target_p, target_p, &me, "Too many failed authentication attempts"); | |
271 | return; | |
272 | } | |
273 | } | |
274 | } | |
275 | else if(*parv[4] == 'S') | |
276 | { | |
277 | if (in_progress) { | |
278 | sendto_one(target_p, form_str(RPL_SASLSUCCESS), me.name, EmptyString(target_p->name) ? "*" : target_p->name); | |
279 | target_p->localClient->sasl_failures = 0; | |
280 | target_p->localClient->sasl_complete = 1; | |
281 | ServerStats.is_ssuc++; | |
282 | } | |
283 | } | |
284 | *target_p->localClient->sasl_agent = '\0'; /* Blank the stored agent so someone else can answer */ | |
285 | target_p->localClient->sasl_messages = 0; | |
286 | } | |
287 | else if(*parv[3] == 'M') | |
288 | { | |
289 | if (in_progress) { | |
290 | sendto_one(target_p, form_str(RPL_SASLMECHS), me.name, EmptyString(target_p->name) ? "*" : target_p->name, parv[4]); | |
291 | } | |
292 | } | |
293 | } | |
294 | ||
295 | static void | |
296 | me_mechlist(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, | |
297 | int parc, const char *parv[]) | |
298 | { | |
299 | rb_strlcpy(mechlist_buf, parv[1], sizeof mechlist_buf); | |
300 | } | |
301 | ||
302 | static void | |
303 | abort_sasl(void *data_) | |
304 | { | |
305 | struct Client *data = data_; | |
306 | if(data->localClient->sasl_out == 0 || data->localClient->sasl_complete) | |
307 | return; | |
308 | ||
309 | data->localClient->sasl_out = data->localClient->sasl_complete = 0; | |
310 | ServerStats.is_sbad++; | |
311 | ||
312 | if(!IsClosing(data)) | |
313 | sendto_one(data, form_str(ERR_SASLABORTED), me.name, EmptyString(data->name) ? "*" : data->name); | |
314 | ||
315 | if(*data->localClient->sasl_agent) | |
316 | { | |
317 | struct Client *agent_p = find_id(data->localClient->sasl_agent); | |
318 | if(agent_p) | |
319 | { | |
320 | sendto_one(agent_p, ":%s ENCAP %s SASL %s %s D A", me.id, agent_p->servptr->name, | |
321 | data->id, agent_p->id); | |
322 | return; | |
323 | } | |
324 | } | |
325 | ||
326 | sendto_server(NULL, NULL, CAP_TS6|CAP_ENCAP, NOCAPS, ":%s ENCAP * SASL %s * D A", me.id, | |
327 | data->id); | |
328 | } | |
329 | ||
330 | static void | |
331 | abort_sasl_exit(void *data_) | |
332 | { | |
333 | hook_data_client_exit *data = data_; | |
334 | if (data->target->localClient) | |
335 | abort_sasl(data->target); | |
336 | } |