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1 | /* | |
2 | * ircd-ratbox: A slightly useful ircd. | |
3 | * m_challenge.c: Allows an IRC Operator to securely authenticate. | |
4 | * | |
5 | * Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center | |
6 | * Copyright (C) 1996-2002 Hybrid Development Team | |
7 | * Copyright (C) 2002-2005 ircd-ratbox development team | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, write to the Free Software | |
21 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 | |
22 | * USA | |
23 | */ | |
24 | ||
25 | #include "stdinc.h" | |
26 | ||
27 | #ifdef HAVE_LIBCRYPTO | |
28 | #include <openssl/pem.h> | |
29 | #include <openssl/rand.h> | |
30 | #include <openssl/rsa.h> | |
31 | #include <openssl/md5.h> | |
32 | #include <openssl/bn.h> | |
33 | #include <openssl/evp.h> | |
34 | #include <openssl/err.h> | |
35 | #endif | |
36 | ||
37 | #include "client.h" | |
38 | #include "ircd.h" | |
39 | #include "modules.h" | |
40 | #include "numeric.h" | |
41 | #include "send.h" | |
42 | #include "s_conf.h" | |
43 | #include "msg.h" | |
44 | #include "parse.h" | |
45 | #include "match.h" | |
46 | #include "logger.h" | |
47 | #include "s_user.h" | |
48 | #include "cache.h" | |
49 | #include "s_newconf.h" | |
50 | ||
51 | #define CHALLENGE_WIDTH BUFSIZE - (NICKLEN + HOSTLEN + 12) | |
52 | #define CHALLENGE_EXPIRES 180 /* 180 seconds should be more than long enough */ | |
53 | #define CHALLENGE_SECRET_LENGTH 128 /* how long our challenge secret should be */ | |
54 | ||
55 | #ifndef HAVE_LIBCRYPTO | |
56 | /* Maybe this should be an error or something?-davidt */ | |
57 | /* now it is -larne */ | |
58 | static int challenge_load(void) | |
59 | { | |
60 | #ifndef STATIC_MODULES | |
61 | sendto_realops_snomask(SNO_GENERAL, L_ALL, | |
62 | "Challenge module not loaded because OpenSSL is not available."); | |
63 | ilog(L_MAIN, "Challenge module not loaded because OpenSSL is not available."); | |
64 | return -1; | |
65 | #else | |
66 | return 0; | |
67 | #endif | |
68 | } | |
69 | ||
70 | static const char challenge_desc[] = "Does nothing as OpenSSL was not enabled."; | |
71 | ||
72 | DECLARE_MODULE_AV2(challenge, challenge_load, NULL, NULL, NULL, NULL, NULL, NULL, challenge_desc); | |
73 | #else | |
74 | ||
75 | static int m_challenge(struct MsgBuf *, struct Client *, struct Client *, int, const char **); | |
76 | ||
77 | /* We have openssl support, so include /CHALLENGE */ | |
78 | struct Message challenge_msgtab = { | |
79 | "CHALLENGE", 0, 0, 0, 0, | |
80 | {mg_unreg, {m_challenge, 2}, mg_ignore, mg_ignore, mg_ignore, {m_challenge, 2}} | |
81 | }; | |
82 | ||
83 | mapi_clist_av1 challenge_clist[] = { &challenge_msgtab, NULL }; | |
84 | ||
85 | static const char challenge_desc[] = | |
86 | "Provides the challenge-response facility used for becoming an IRC operator"; | |
87 | ||
88 | ||
89 | DECLARE_MODULE_AV2(challenge, NULL, NULL, challenge_clist, NULL, NULL, NULL, NULL, challenge_desc); | |
90 | ||
91 | static int generate_challenge(char **r_challenge, char **r_response, RSA * key); | |
92 | ||
93 | static void | |
94 | cleanup_challenge(struct Client *target_p) | |
95 | { | |
96 | if(target_p->localClient == NULL) | |
97 | return; | |
98 | ||
99 | rb_free(target_p->localClient->challenge); | |
100 | rb_free(target_p->localClient->opername); | |
101 | target_p->localClient->challenge = NULL; | |
102 | target_p->localClient->opername = NULL; | |
103 | target_p->localClient->chal_time = 0; | |
104 | } | |
105 | ||
106 | /* | |
107 | * m_challenge - generate RSA challenge for wouldbe oper | |
108 | * parv[1] = operator to challenge for, or +response | |
109 | */ | |
110 | static int | |
111 | m_challenge(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, int parc, const char *parv[]) | |
112 | { | |
113 | struct oper_conf *oper_p; | |
114 | char *challenge = NULL; /* to placate gcc */ | |
115 | char chal_line[CHALLENGE_WIDTH]; | |
116 | unsigned char *b_response; | |
117 | size_t cnt; | |
118 | int len = 0; | |
119 | ||
120 | /* if theyre an oper, reprint oper motd and ignore */ | |
121 | if(IsOper(source_p)) | |
122 | { | |
123 | sendto_one(source_p, form_str(RPL_YOUREOPER), me.name, source_p->name); | |
124 | send_oper_motd(source_p); | |
125 | return 0; | |
126 | } | |
127 | ||
128 | if(*parv[1] == '+') | |
129 | { | |
130 | /* Ignore it if we aren't expecting this... -A1kmm */ | |
131 | if(!source_p->localClient->challenge) | |
132 | return 0; | |
133 | ||
134 | if((rb_current_time() - source_p->localClient->chal_time) > CHALLENGE_EXPIRES) | |
135 | { | |
136 | sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name); | |
137 | ilog(L_FOPER, "EXPIRED CHALLENGE (%s) by (%s!%s@%s) (%s)", | |
138 | source_p->localClient->opername, source_p->name, | |
139 | source_p->username, source_p->host, source_p->sockhost); | |
140 | ||
141 | if(ConfigFileEntry.failed_oper_notice) | |
142 | sendto_realops_snomask(SNO_GENERAL, L_NETWIDE, | |
143 | "Expired CHALLENGE attempt by %s (%s@%s)", | |
144 | source_p->name, source_p->username, | |
145 | source_p->host); | |
146 | cleanup_challenge(source_p); | |
147 | return 0; | |
148 | } | |
149 | ||
150 | parv[1]++; | |
151 | b_response = rb_base64_decode((const unsigned char *)parv[1], strlen(parv[1]), &len); | |
152 | ||
153 | if(len != SHA_DIGEST_LENGTH || | |
154 | memcmp(source_p->localClient->challenge, b_response, SHA_DIGEST_LENGTH)) | |
155 | { | |
156 | sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name); | |
157 | ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s)", | |
158 | source_p->localClient->opername, source_p->name, | |
159 | source_p->username, source_p->host, source_p->sockhost); | |
160 | ||
161 | if(ConfigFileEntry.failed_oper_notice) | |
162 | sendto_realops_snomask(SNO_GENERAL, L_NETWIDE, | |
163 | "Failed CHALLENGE attempt by %s (%s@%s)", | |
164 | source_p->name, source_p->username, | |
165 | source_p->host); | |
166 | ||
167 | rb_free(b_response); | |
168 | cleanup_challenge(source_p); | |
169 | return 0; | |
170 | } | |
171 | ||
172 | rb_free(b_response); | |
173 | ||
174 | oper_p = find_oper_conf(source_p->username, source_p->orighost, | |
175 | source_p->sockhost, | |
176 | source_p->localClient->opername); | |
177 | ||
178 | if(oper_p == NULL) | |
179 | { | |
180 | sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST)); | |
181 | ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)", | |
182 | source_p->localClient->opername, source_p->name, | |
183 | source_p->username, source_p->host, | |
184 | source_p->sockhost); | |
185 | ||
186 | if(ConfigFileEntry.failed_oper_notice) | |
187 | sendto_realops_snomask(SNO_GENERAL, L_NETWIDE, | |
188 | "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)", | |
189 | source_p->name, source_p->username, | |
190 | source_p->host); | |
191 | return 0; | |
192 | } | |
193 | ||
194 | cleanup_challenge(source_p); | |
195 | ||
196 | oper_up(source_p, oper_p); | |
197 | ||
198 | ilog(L_OPERED, "OPER %s by %s!%s@%s (%s)", | |
199 | source_p->localClient->opername, source_p->name, | |
200 | source_p->username, source_p->host, source_p->sockhost); | |
201 | return 0; | |
202 | } | |
203 | ||
204 | cleanup_challenge(source_p); | |
205 | ||
206 | oper_p = find_oper_conf(source_p->username, source_p->orighost, | |
207 | source_p->sockhost, parv[1]); | |
208 | ||
209 | if(oper_p == NULL) | |
210 | { | |
211 | sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST)); | |
212 | ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)", | |
213 | parv[1], source_p->name, | |
214 | source_p->username, source_p->host, source_p->sockhost); | |
215 | ||
216 | if(ConfigFileEntry.failed_oper_notice) | |
217 | sendto_realops_snomask(SNO_GENERAL, L_NETWIDE, | |
218 | "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)", | |
219 | source_p->name, source_p->username, source_p->host); | |
220 | return 0; | |
221 | } | |
222 | ||
223 | if(!oper_p->rsa_pubkey) | |
224 | { | |
225 | sendto_one_notice(source_p, ":I'm sorry, PK authentication is not enabled for your oper{} block."); | |
226 | return 0; | |
227 | } | |
228 | ||
229 | if(IsOperConfNeedSSL(oper_p) && !IsSSLClient(source_p)) | |
230 | { | |
231 | sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST)); | |
232 | ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s) -- requires SSL/TLS", | |
233 | parv[1], source_p->name, source_p->username, source_p->host, | |
234 | source_p->sockhost); | |
235 | ||
236 | if(ConfigFileEntry.failed_oper_notice) | |
237 | { | |
238 | sendto_realops_snomask(SNO_GENERAL, L_ALL, | |
239 | "Failed CHALLENGE attempt - missing SSL/TLS by %s (%s@%s)", | |
240 | source_p->name, source_p->username, source_p->host); | |
241 | } | |
242 | return 0; | |
243 | } | |
244 | ||
245 | if (oper_p->certfp != NULL) | |
246 | { | |
247 | if (source_p->certfp == NULL || strcasecmp(source_p->certfp, oper_p->certfp)) | |
248 | { | |
249 | sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST)); | |
250 | ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s) -- client certificate fingerprint mismatch", | |
251 | parv[1], source_p->name, | |
252 | source_p->username, source_p->host, source_p->sockhost); | |
253 | ||
254 | if(ConfigFileEntry.failed_oper_notice) | |
255 | { | |
256 | sendto_realops_snomask(SNO_GENERAL, L_ALL, | |
257 | "Failed OPER attempt - client certificate fingerprint mismatch by %s (%s@%s)", | |
258 | source_p->name, source_p->username, source_p->host); | |
259 | } | |
260 | return 0; | |
261 | } | |
262 | } | |
263 | ||
264 | if(!generate_challenge(&challenge, &(source_p->localClient->challenge), oper_p->rsa_pubkey)) | |
265 | { | |
266 | char *chal = challenge; | |
267 | source_p->localClient->chal_time = rb_current_time(); | |
268 | for(;;) | |
269 | { | |
270 | cnt = rb_strlcpy(chal_line, chal, CHALLENGE_WIDTH); | |
271 | sendto_one(source_p, form_str(RPL_RSACHALLENGE2), me.name, source_p->name, chal_line); | |
272 | if(cnt > CHALLENGE_WIDTH) | |
273 | chal += CHALLENGE_WIDTH - 1; | |
274 | else | |
275 | break; | |
276 | ||
277 | } | |
278 | sendto_one(source_p, form_str(RPL_ENDOFRSACHALLENGE2), | |
279 | me.name, source_p->name); | |
280 | rb_free(challenge); | |
281 | source_p->localClient->opername = rb_strdup(oper_p->name); | |
282 | } | |
283 | else | |
284 | sendto_one_notice(source_p, ":Failed to generate challenge."); | |
285 | ||
286 | return 0; | |
287 | } | |
288 | ||
289 | static int | |
290 | generate_challenge(char **r_challenge, char **r_response, RSA * rsa) | |
291 | { | |
292 | SHA_CTX ctx; | |
293 | unsigned char secret[CHALLENGE_SECRET_LENGTH], *tmp; | |
294 | unsigned long length; | |
295 | unsigned long e = 0; | |
296 | unsigned long cnt = 0; | |
297 | int ret; | |
298 | ||
299 | if(!rsa) | |
300 | return -1; | |
301 | if(rb_get_random(secret, CHALLENGE_SECRET_LENGTH)) | |
302 | { | |
303 | SHA1_Init(&ctx); | |
304 | SHA1_Update(&ctx, (uint8_t *)secret, CHALLENGE_SECRET_LENGTH); | |
305 | *r_response = malloc(SHA_DIGEST_LENGTH); | |
306 | SHA1_Final((uint8_t *)*r_response, &ctx); | |
307 | ||
308 | length = RSA_size(rsa); | |
309 | tmp = rb_malloc(length); | |
310 | ret = RSA_public_encrypt(CHALLENGE_SECRET_LENGTH, secret, tmp, rsa, RSA_PKCS1_OAEP_PADDING); | |
311 | ||
312 | if(ret >= 0) | |
313 | { | |
314 | *r_challenge = (char *)rb_base64_encode(tmp, ret); | |
315 | rb_free(tmp); | |
316 | return 0; | |
317 | } | |
318 | ||
319 | rb_free(tmp); | |
320 | rb_free(*r_response); | |
321 | *r_response = NULL; | |
322 | } | |
323 | ||
324 | ERR_load_crypto_strings(); | |
325 | while ((cnt < 100) && (e = ERR_get_error())) | |
326 | { | |
327 | ilog(L_MAIN, "SSL error: %s", ERR_error_string(e, 0)); | |
328 | cnt++; | |
329 | } | |
330 | ||
331 | return (-1); | |
332 | } | |
333 | ||
334 | #endif /* HAVE_LIBCRYPTO */ |