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m_challenge: fix use of undefined behaviour.
[irc/rqf/shadowircd.git] / modules / m_challenge.c
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212380e3 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 *
212380e3 24 */
25
26#include "stdinc.h"
27
28#ifdef HAVE_LIBCRYPTO
29#include <openssl/pem.h>
30#include <openssl/rand.h>
31#include <openssl/rsa.h>
32#include <openssl/md5.h>
33#include <openssl/bn.h>
34#include <openssl/evp.h>
35#include <openssl/err.h>
36#endif
37
212380e3 38#include "client.h"
39#include "ircd.h"
40#include "modules.h"
41#include "numeric.h"
42#include "send.h"
43#include "s_conf.h"
44#include "msg.h"
45#include "parse.h"
13ae2f4b 46#include "match.h"
d3455e2c 47#include "logger.h"
212380e3 48#include "s_user.h"
49#include "cache.h"
50#include "s_newconf.h"
51
52#define CHALLENGE_WIDTH BUFSIZE - (NICKLEN + HOSTLEN + 12)
53#define CHALLENGE_EXPIRES 180 /* 180 seconds should be more than long enough */
54#define CHALLENGE_SECRET_LENGTH 128 /* how long our challenge secret should be */
55
56#ifndef HAVE_LIBCRYPTO
57/* Maybe this should be an error or something?-davidt */
58/* now it is -larne */
59static int challenge_load(void)
60{
61#ifndef STATIC_MODULES
62 sendto_realops_snomask(SNO_GENERAL, L_ALL,
63 "Challenge module not loaded because OpenSSL is not available.");
64 ilog(L_MAIN, "Challenge module not loaded because OpenSSL is not available.");
65 return -1;
66#else
67 return 0;
68#endif
69}
70
5366977b 71DECLARE_MODULE_AV1(challenge, challenge_load, NULL, NULL, NULL, NULL, "$Revision: 3161 $");
212380e3 72#else
73
74static int m_challenge(struct Client *, struct Client *, int, const char **);
75
76/* We have openssl support, so include /CHALLENGE */
77struct Message challenge_msgtab = {
78 "CHALLENGE", 0, 0, 0, MFLG_SLOW,
79 {mg_unreg, {m_challenge, 2}, mg_ignore, mg_ignore, mg_ignore, {m_challenge, 2}}
80};
81
82mapi_clist_av1 challenge_clist[] = { &challenge_msgtab, NULL };
5366977b 83DECLARE_MODULE_AV1(challenge, NULL, NULL, challenge_clist, NULL, NULL, "$Revision: 3161 $");
212380e3 84
85static int generate_challenge(char **r_challenge, char **r_response, RSA * key);
86
87static void
88cleanup_challenge(struct Client *target_p)
89{
90 if(target_p->localClient == NULL)
91 return;
92
90a3c35b
VY
93 rb_free(target_p->localClient->challenge);
94 rb_free(target_p->localClient->opername);
212380e3 95 target_p->localClient->challenge = NULL;
96 target_p->localClient->opername = NULL;
97 target_p->localClient->chal_time = 0;
98}
99
100/*
101 * m_challenge - generate RSA challenge for wouldbe oper
212380e3 102 * parv[1] = operator to challenge for, or +response
103 *
104 */
105static int
106m_challenge(struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
107{
108 struct oper_conf *oper_p;
109 char *challenge = NULL; /* to placate gcc */
110 char chal_line[CHALLENGE_WIDTH];
111 unsigned char *b_response;
112 size_t cnt;
113 int len = 0;
114
115 /* if theyre an oper, reprint oper motd and ignore */
116 if(IsOper(source_p))
117 {
118 sendto_one(source_p, form_str(RPL_YOUREOPER), me.name, source_p->name);
119 send_oper_motd(source_p);
120 return 0;
121 }
122
123 if(*parv[1] == '+')
124 {
125 /* Ignore it if we aren't expecting this... -A1kmm */
126 if(!source_p->localClient->challenge)
127 return 0;
128
9f6bbe3c 129 if((rb_current_time() - source_p->localClient->chal_time) > CHALLENGE_EXPIRES)
212380e3 130 {
131 sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
132 ilog(L_FOPER, "EXPIRED CHALLENGE (%s) by (%s!%s@%s) (%s)",
133 source_p->localClient->opername, source_p->name,
134 source_p->username, source_p->host, source_p->sockhost);
135
136 if(ConfigFileEntry.failed_oper_notice)
137 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
138 "Expired CHALLENGE attempt by %s (%s@%s)",
139 source_p->name, source_p->username,
140 source_p->host);
141 cleanup_challenge(source_p);
142 return 0;
143 }
144
d9c25796
EJM
145 parv[1]++;
146 b_response = rb_base64_decode((const unsigned char *)parv[1], strlen(parv[1]), &len);
212380e3 147
148 if(len != SHA_DIGEST_LENGTH ||
149 memcmp(source_p->localClient->challenge, b_response, SHA_DIGEST_LENGTH))
150 {
151 sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
152 ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s)",
153 source_p->localClient->opername, source_p->name,
154 source_p->username, source_p->host, source_p->sockhost);
155
156 if(ConfigFileEntry.failed_oper_notice)
157 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
158 "Failed CHALLENGE attempt by %s (%s@%s)",
159 source_p->name, source_p->username,
160 source_p->host);
161
90a3c35b 162 rb_free(b_response);
212380e3 163 cleanup_challenge(source_p);
164 return 0;
165 }
166
90a3c35b 167 rb_free(b_response);
212380e3 168
169 oper_p = find_oper_conf(source_p->username, source_p->orighost,
170 source_p->sockhost,
171 source_p->localClient->opername);
172
173 if(oper_p == NULL)
174 {
e4c72f79 175 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
212380e3 176 ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
177 source_p->localClient->opername, source_p->name,
178 source_p->username, source_p->host,
179 source_p->sockhost);
180
181 if(ConfigFileEntry.failed_oper_notice)
182 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
183 "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
184 source_p->name, source_p->username,
185 source_p->host);
186 return 0;
187 }
188
189 cleanup_challenge(source_p);
190
191 oper_up(source_p, oper_p);
192
193 ilog(L_OPERED, "OPER %s by %s!%s@%s (%s)",
194 source_p->localClient->opername, source_p->name,
195 source_p->username, source_p->host, source_p->sockhost);
196 return 0;
197 }
198
199 cleanup_challenge(source_p);
200
201 oper_p = find_oper_conf(source_p->username, source_p->orighost,
202 source_p->sockhost, parv[1]);
203
204 if(oper_p == NULL)
205 {
e4c72f79 206 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
212380e3 207 ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
208 parv[1], source_p->name,
209 source_p->username, source_p->host, source_p->sockhost);
210
211 if(ConfigFileEntry.failed_oper_notice)
212 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
213 "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
214 source_p->name, source_p->username, source_p->host);
215 return 0;
216 }
217
218 if(!oper_p->rsa_pubkey)
219 {
5366977b 220 sendto_one_notice(source_p, ":I'm sorry, PK authentication is not enabled for your oper{} block.");
212380e3 221 return 0;
222 }
223
663bbb28
JT
224 if(IsOperConfNeedSSL(oper_p) && !IsSSLClient(source_p))
225 {
e4c72f79 226 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
663bbb28
JT
227 ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s) -- requires SSL/TLS",
228 parv[1], source_p->name, source_p->username, source_p->host,
229 source_p->sockhost);
230
231 if(ConfigFileEntry.failed_oper_notice)
232 {
233 sendto_realops_snomask(SNO_GENERAL, L_ALL,
234 "Failed CHALLENGE attempt - missing SSL/TLS by %s (%s@%s)",
235 source_p->name, source_p->username, source_p->host);
236 }
237 return 0;
238 }
239
1c19179d
WP
240 if (oper_p->certfp != NULL)
241 {
242 if (source_p->certfp == NULL || strcasecmp(source_p->certfp, oper_p->certfp))
243 {
244 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
245 ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s) -- client certificate fingerprint mismatch",
8a64e49e 246 parv[1], source_p->name,
1c19179d
WP
247 source_p->username, source_p->host, source_p->sockhost);
248
249 if(ConfigFileEntry.failed_oper_notice)
250 {
251 sendto_realops_snomask(SNO_GENERAL, L_ALL,
252 "Failed OPER attempt - client certificate fingerprint mismatch by %s (%s@%s)",
253 source_p->name, source_p->username, source_p->host);
254 }
255 return 0;
256 }
257 }
258
212380e3 259 if(!generate_challenge(&challenge, &(source_p->localClient->challenge), oper_p->rsa_pubkey))
260 {
261 char *chal = challenge;
9f6bbe3c 262 source_p->localClient->chal_time = rb_current_time();
212380e3 263 for(;;)
264 {
907468c4 265 cnt = rb_strlcpy(chal_line, chal, CHALLENGE_WIDTH);
212380e3 266 sendto_one(source_p, form_str(RPL_RSACHALLENGE2), me.name, source_p->name, chal_line);
267 if(cnt > CHALLENGE_WIDTH)
268 chal += CHALLENGE_WIDTH - 1;
269 else
270 break;
271
272 }
273 sendto_one(source_p, form_str(RPL_ENDOFRSACHALLENGE2),
274 me.name, source_p->name);
90a3c35b 275 rb_free(challenge);
8e43b0b4 276 source_p->localClient->opername = rb_strdup(oper_p->name);
212380e3 277 }
278 else
279 sendto_one_notice(source_p, ":Failed to generate challenge.");
280
281 return 0;
282}
283
212380e3 284static int
285generate_challenge(char **r_challenge, char **r_response, RSA * rsa)
286{
287 SHA_CTX ctx;
288 unsigned char secret[CHALLENGE_SECRET_LENGTH], *tmp;
289 unsigned long length;
290 unsigned long e = 0;
291 unsigned long cnt = 0;
292 int ret;
293
294 if(!rsa)
295 return -1;
26673969 296 if(rb_get_random(secret, CHALLENGE_SECRET_LENGTH))
212380e3 297 {
298 SHA1_Init(&ctx);
26673969
VY
299 SHA1_Update(&ctx, (uint8_t *)secret, CHALLENGE_SECRET_LENGTH);
300 *r_response = malloc(SHA_DIGEST_LENGTH);
301 SHA1_Final((uint8_t *)*r_response, &ctx);
212380e3 302
303 length = RSA_size(rsa);
8e43b0b4 304 tmp = rb_malloc(length);
212380e3 305 ret = RSA_public_encrypt(CHALLENGE_SECRET_LENGTH, secret, tmp, rsa, RSA_PKCS1_OAEP_PADDING);
306
26673969 307 if(ret >= 0)
212380e3 308 {
26673969 309 *r_challenge = (char *)rb_base64_encode(tmp, ret);
90a3c35b 310 rb_free(tmp);
212380e3 311 return 0;
312 }
26673969 313
90a3c35b
VY
314 rb_free(tmp);
315 rb_free(*r_response);
212380e3 316 *r_response = NULL;
317 }
318
319 ERR_load_crypto_strings();
320 while ((cnt < 100) && (e = ERR_get_error()))
321 {
322 ilog(L_MAIN, "SSL error: %s", ERR_error_string(e, 0));
323 cnt++;
324 }
325
326 return (-1);
327}
328
329#endif /* HAVE_LIBCRYPTO */