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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 | ||
57 | static const char challenge_desc[] = "Does nothing as OpenSSL was not enabled."; | |
58 | ||
59 | /* Maybe this should be an error or something?-davidt */ | |
60 | /* now it is -larne */ | |
61 | static int challenge_load(void) | |
62 | { | |
63 | sendto_realops_snomask(SNO_GENERAL, L_ALL, | |
64 | "Challenge module not loaded because OpenSSL is not available."); | |
65 | ilog(L_MAIN, "Challenge module not loaded because OpenSSL is not available."); | |
66 | return -1; | |
67 | } | |
68 | ||
69 | DECLARE_MODULE_AV2(challenge, challenge_load, NULL, NULL, NULL, NULL, NULL, NULL, challenge_desc); | |
70 | #else | |
71 | ||
72 | static const char challenge_desc[] = | |
73 | "Provides the challenge-response facility used for becoming an IRC operator"; | |
74 | ||
75 | static void 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 | DECLARE_MODULE_AV2(challenge, NULL, NULL, challenge_clist, NULL, NULL, NULL, NULL, challenge_desc); | |
86 | ||
87 | static bool generate_challenge(char **r_challenge, char **r_response, RSA * key); | |
88 | ||
89 | static void | |
90 | cleanup_challenge(struct Client *target_p) | |
91 | { | |
92 | if(target_p->localClient == NULL) | |
93 | return; | |
94 | ||
95 | rb_free(target_p->localClient->challenge); | |
96 | rb_free(target_p->localClient->opername); | |
97 | target_p->localClient->challenge = NULL; | |
98 | target_p->localClient->opername = NULL; | |
99 | target_p->localClient->chal_time = 0; | |
100 | } | |
101 | ||
102 | /* | |
103 | * m_challenge - generate RSA challenge for wouldbe oper | |
104 | * parv[1] = operator to challenge for, or +response | |
105 | */ | |
106 | static void | |
107 | m_challenge(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, int parc, const char *parv[]) | |
108 | { | |
109 | struct oper_conf *oper_p; | |
110 | char *challenge = NULL; /* to placate gcc */ | |
111 | char chal_line[CHALLENGE_WIDTH]; | |
112 | unsigned char *b_response; | |
113 | size_t cnt; | |
114 | int len = 0; | |
115 | ||
116 | /* if theyre an oper, reprint oper motd and ignore */ | |
117 | if(IsOper(source_p)) | |
118 | { | |
119 | sendto_one(source_p, form_str(RPL_YOUREOPER), me.name, source_p->name); | |
120 | send_oper_motd(source_p); | |
121 | return; | |
122 | } | |
123 | ||
124 | if(*parv[1] == '+') | |
125 | { | |
126 | /* Ignore it if we aren't expecting this... -A1kmm */ | |
127 | if(!source_p->localClient->challenge) | |
128 | return; | |
129 | ||
130 | if((rb_current_time() - source_p->localClient->chal_time) > CHALLENGE_EXPIRES) | |
131 | { | |
132 | sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name); | |
133 | ilog(L_FOPER, "EXPIRED CHALLENGE (%s) by (%s!%s@%s) (%s)", | |
134 | source_p->localClient->opername, source_p->name, | |
135 | source_p->username, source_p->host, source_p->sockhost); | |
136 | ||
137 | if(ConfigFileEntry.failed_oper_notice) | |
138 | sendto_realops_snomask(SNO_GENERAL, L_NETWIDE, | |
139 | "Expired CHALLENGE attempt by %s (%s@%s)", | |
140 | source_p->name, source_p->username, | |
141 | source_p->host); | |
142 | cleanup_challenge(source_p); | |
143 | return; | |
144 | } | |
145 | ||
146 | parv[1]++; | |
147 | b_response = rb_base64_decode((const unsigned char *)parv[1], strlen(parv[1]), &len); | |
148 | ||
149 | if(len != SHA_DIGEST_LENGTH || | |
150 | memcmp(source_p->localClient->challenge, b_response, SHA_DIGEST_LENGTH)) | |
151 | { | |
152 | sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name); | |
153 | ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s)", | |
154 | source_p->localClient->opername, source_p->name, | |
155 | source_p->username, source_p->host, source_p->sockhost); | |
156 | ||
157 | if(ConfigFileEntry.failed_oper_notice) | |
158 | sendto_realops_snomask(SNO_GENERAL, L_NETWIDE, | |
159 | "Failed CHALLENGE attempt by %s (%s@%s)", | |
160 | source_p->name, source_p->username, | |
161 | source_p->host); | |
162 | ||
163 | rb_free(b_response); | |
164 | cleanup_challenge(source_p); | |
165 | return; | |
166 | } | |
167 | ||
168 | rb_free(b_response); | |
169 | ||
170 | oper_p = find_oper_conf(source_p->username, source_p->orighost, | |
171 | source_p->sockhost, | |
172 | source_p->localClient->opername); | |
173 | ||
174 | if(oper_p == NULL) | |
175 | { | |
176 | sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST)); | |
177 | ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)", | |
178 | source_p->localClient->opername, source_p->name, | |
179 | source_p->username, source_p->host, | |
180 | source_p->sockhost); | |
181 | ||
182 | if(ConfigFileEntry.failed_oper_notice) | |
183 | sendto_realops_snomask(SNO_GENERAL, L_NETWIDE, | |
184 | "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)", | |
185 | source_p->name, source_p->username, | |
186 | source_p->host); | |
187 | return; | |
188 | } | |
189 | ||
190 | cleanup_challenge(source_p); | |
191 | ||
192 | oper_up(source_p, oper_p); | |
193 | ||
194 | ilog(L_OPERED, "OPER %s by %s!%s@%s (%s)", | |
195 | source_p->localClient->opername, source_p->name, | |
196 | source_p->username, source_p->host, source_p->sockhost); | |
197 | return; | |
198 | } | |
199 | ||
200 | cleanup_challenge(source_p); | |
201 | ||
202 | oper_p = find_oper_conf(source_p->username, source_p->orighost, | |
203 | source_p->sockhost, parv[1]); | |
204 | ||
205 | if(oper_p == NULL) | |
206 | { | |
207 | sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST)); | |
208 | ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)", | |
209 | parv[1], source_p->name, | |
210 | source_p->username, source_p->host, source_p->sockhost); | |
211 | ||
212 | if(ConfigFileEntry.failed_oper_notice) | |
213 | sendto_realops_snomask(SNO_GENERAL, L_NETWIDE, | |
214 | "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)", | |
215 | source_p->name, source_p->username, source_p->host); | |
216 | return; | |
217 | } | |
218 | ||
219 | if(!oper_p->rsa_pubkey) | |
220 | { | |
221 | sendto_one_notice(source_p, ":I'm sorry, PK authentication is not enabled for your oper{} block."); | |
222 | return; | |
223 | } | |
224 | ||
225 | if(IsOperConfNeedSSL(oper_p) && !IsSSLClient(source_p)) | |
226 | { | |
227 | sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST)); | |
228 | ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s) -- requires SSL/TLS", | |
229 | parv[1], source_p->name, source_p->username, source_p->host, | |
230 | source_p->sockhost); | |
231 | ||
232 | if(ConfigFileEntry.failed_oper_notice) | |
233 | { | |
234 | sendto_realops_snomask(SNO_GENERAL, L_ALL, | |
235 | "Failed CHALLENGE attempt - missing SSL/TLS by %s (%s@%s)", | |
236 | source_p->name, source_p->username, source_p->host); | |
237 | } | |
238 | return; | |
239 | } | |
240 | ||
241 | if (oper_p->certfp != NULL) | |
242 | { | |
243 | if (source_p->certfp == NULL || strcasecmp(source_p->certfp, oper_p->certfp)) | |
244 | { | |
245 | sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST)); | |
246 | ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s) -- client certificate fingerprint mismatch", | |
247 | parv[1], source_p->name, | |
248 | source_p->username, source_p->host, source_p->sockhost); | |
249 | ||
250 | if(ConfigFileEntry.failed_oper_notice) | |
251 | { | |
252 | sendto_realops_snomask(SNO_GENERAL, L_ALL, | |
253 | "Failed OPER attempt - client certificate fingerprint mismatch by %s (%s@%s)", | |
254 | source_p->name, source_p->username, source_p->host); | |
255 | } | |
256 | return; | |
257 | } | |
258 | } | |
259 | ||
260 | if(generate_challenge(&challenge, &(source_p->localClient->challenge), oper_p->rsa_pubkey)) | |
261 | { | |
262 | char *chal = challenge; | |
263 | source_p->localClient->chal_time = rb_current_time(); | |
264 | for(;;) | |
265 | { | |
266 | cnt = rb_strlcpy(chal_line, chal, CHALLENGE_WIDTH); | |
267 | sendto_one(source_p, form_str(RPL_RSACHALLENGE2), me.name, source_p->name, chal_line); | |
268 | if(cnt > CHALLENGE_WIDTH) | |
269 | chal += CHALLENGE_WIDTH - 1; | |
270 | else | |
271 | break; | |
272 | ||
273 | } | |
274 | sendto_one(source_p, form_str(RPL_ENDOFRSACHALLENGE2), | |
275 | me.name, source_p->name); | |
276 | rb_free(challenge); | |
277 | source_p->localClient->opername = rb_strdup(oper_p->name); | |
278 | } | |
279 | else | |
280 | sendto_one_notice(source_p, ":Failed to generate challenge."); | |
281 | } | |
282 | ||
283 | static bool | |
284 | generate_challenge(char **r_challenge, char **r_response, RSA * rsa) | |
285 | { | |
286 | SHA_CTX ctx; | |
287 | unsigned char secret[CHALLENGE_SECRET_LENGTH], *tmp; | |
288 | unsigned long length; | |
289 | unsigned long e = 0; | |
290 | unsigned long cnt = 0; | |
291 | int ret; | |
292 | ||
293 | if(!rsa) | |
294 | return false; | |
295 | if(rb_get_random(secret, CHALLENGE_SECRET_LENGTH)) | |
296 | { | |
297 | SHA1_Init(&ctx); | |
298 | SHA1_Update(&ctx, (uint8_t *)secret, CHALLENGE_SECRET_LENGTH); | |
299 | *r_response = malloc(SHA_DIGEST_LENGTH); | |
300 | SHA1_Final((uint8_t *)*r_response, &ctx); | |
301 | ||
302 | length = RSA_size(rsa); | |
303 | tmp = rb_malloc(length); | |
304 | ret = RSA_public_encrypt(CHALLENGE_SECRET_LENGTH, secret, tmp, rsa, RSA_PKCS1_OAEP_PADDING); | |
305 | ||
306 | if(ret >= 0) | |
307 | { | |
308 | *r_challenge = (char *)rb_base64_encode(tmp, ret); | |
309 | rb_free(tmp); | |
310 | return true; | |
311 | } | |
312 | ||
313 | rb_free(tmp); | |
314 | rb_free(*r_response); | |
315 | *r_response = NULL; | |
316 | } | |
317 | ||
318 | ERR_load_crypto_strings(); | |
319 | while ((cnt < 100) && (e = ERR_get_error())) | |
320 | { | |
321 | ilog(L_MAIN, "SSL error: %s", ERR_error_string(e, 0)); | |
322 | cnt++; | |
323 | } | |
324 | ||
325 | return false; | |
326 | } | |
327 | ||
328 | #endif /* HAVE_LIBCRYPTO */ |