1 /*
2 * Copyright (C) 2012 by Darren Reed.
3 *
4 * See the IPFILTER.LICENCE file for details on licencing.
5 *
6 * Simple ISAKMP transparent proxy for in-kernel use. For use with the NAT
7 * code.
8 *
9 * $Id$
10 *
11 */
12 #define IPF_IPSEC_PROXY
13
14
15 /*
16 * IPSec proxy
17 */
18 typedef struct ipf_ipsec_softc_s {
19 frentry_t ipsec_fr;
20 int ipsec_proxy_init;
21 int ipsec_proxy_ttl;
22 ipftq_t *ipsec_nat_tqe;
23 ipftq_t *ipsec_state_tqe;
24 char ipsec_buffer[1500];
25 } ipf_ipsec_softc_t;
26
27
28 void *ipf_p_ipsec_soft_create __P((ipf_main_softc_t *));
29 void ipf_p_ipsec_soft_destroy __P((ipf_main_softc_t *, void *));
30 int ipf_p_ipsec_soft_init __P((ipf_main_softc_t *, void *));
31 void ipf_p_ipsec_soft_fini __P((ipf_main_softc_t *, void *));
32 int ipf_p_ipsec_init __P((void));
33 void ipf_p_ipsec_fini __P((void));
34 int ipf_p_ipsec_new __P((void *, fr_info_t *, ap_session_t *, nat_t *));
35 void ipf_p_ipsec_del __P((ipf_main_softc_t *, ap_session_t *));
36 int ipf_p_ipsec_inout __P((void *, fr_info_t *, ap_session_t *, nat_t *));
37 int ipf_p_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *));
38
39
40 /*
41 * IPSec application proxy initialization.
42 */
43 void *
ipf_p_ipsec_soft_create(softc)44 ipf_p_ipsec_soft_create(softc)
45 ipf_main_softc_t *softc;
46 {
47 ipf_ipsec_softc_t *softi;
48
49 KMALLOC(softi, ipf_ipsec_softc_t *);
50 if (softi == NULL)
51 return NULL;
52
53 bzero((char *)softi, sizeof(*softi));
54 softi->ipsec_fr.fr_ref = 1;
55 softi->ipsec_fr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
56 MUTEX_INIT(&softi->ipsec_fr.fr_lock, "IPsec proxy rule lock");
57 softi->ipsec_proxy_init = 1;
58 softi->ipsec_proxy_ttl = 60;
59
60 return softi;
61 }
62
63
64 int
ipf_p_ipsec_soft_init(softc,arg)65 ipf_p_ipsec_soft_init(softc, arg)
66 ipf_main_softc_t *softc;
67 void *arg;
68 {
69 ipf_ipsec_softc_t *softi = arg;
70
71 softi->ipsec_nat_tqe = ipf_state_add_tq(softc, softi->ipsec_proxy_ttl);
72 if (softi->ipsec_nat_tqe == NULL)
73 return -1;
74 softi->ipsec_state_tqe = ipf_nat_add_tq(softc, softi->ipsec_proxy_ttl);
75 if (softi->ipsec_state_tqe == NULL) {
76 if (ipf_deletetimeoutqueue(softi->ipsec_nat_tqe) == 0)
77 ipf_freetimeoutqueue(softc, softi->ipsec_nat_tqe);
78 softi->ipsec_nat_tqe = NULL;
79 return -1;
80 }
81
82 softi->ipsec_nat_tqe->ifq_flags |= IFQF_PROXY;
83 softi->ipsec_state_tqe->ifq_flags |= IFQF_PROXY;
84 softi->ipsec_fr.fr_age[0] = softi->ipsec_proxy_ttl;
85 softi->ipsec_fr.fr_age[1] = softi->ipsec_proxy_ttl;
86 return 0;
87 }
88
89
90 void
ipf_p_ipsec_soft_fini(softc,arg)91 ipf_p_ipsec_soft_fini(softc, arg)
92 ipf_main_softc_t *softc;
93 void *arg;
94 {
95 ipf_ipsec_softc_t *softi = arg;
96
97 if (arg == NULL)
98 return;
99
100 if (softi->ipsec_nat_tqe != NULL) {
101 if (ipf_deletetimeoutqueue(softi->ipsec_nat_tqe) == 0)
102 ipf_freetimeoutqueue(softc, softi->ipsec_nat_tqe);
103 }
104 softi->ipsec_nat_tqe = NULL;
105 if (softi->ipsec_state_tqe != NULL) {
106 if (ipf_deletetimeoutqueue(softi->ipsec_state_tqe) == 0)
107 ipf_freetimeoutqueue(softc, softi->ipsec_state_tqe);
108 }
109 softi->ipsec_state_tqe = NULL;
110 }
111
112
113 void
ipf_p_ipsec_soft_destroy(softc,arg)114 ipf_p_ipsec_soft_destroy(softc, arg)
115 ipf_main_softc_t *softc;
116 void *arg;
117 {
118 ipf_ipsec_softc_t *softi = arg;
119
120 if (softi->ipsec_proxy_init == 1) {
121 MUTEX_DESTROY(&softi->ipsec_fr.fr_lock);
122 softi->ipsec_proxy_init = 0;
123 }
124
125 KFREE(softi);
126 }
127
128
129 /*
130 * Setup for a new IPSEC proxy.
131 */
132 int
ipf_p_ipsec_new(arg,fin,aps,nat)133 ipf_p_ipsec_new(arg, fin, aps, nat)
134 void *arg;
135 fr_info_t *fin;
136 ap_session_t *aps;
137 nat_t *nat;
138 {
139 ipf_ipsec_softc_t *softi = arg;
140 ipf_main_softc_t *softc = fin->fin_main_soft;
141 #ifdef USE_MUTEXES
142 ipf_nat_softc_t *softn = softc->ipf_nat_soft;
143 #endif
144 int p, off, dlen, ttl;
145 ipsec_pxy_t *ipsec;
146 ipnat_t *ipn, *np;
147 fr_info_t fi;
148 char *ptr;
149 int size;
150 ip_t *ip;
151 mb_t *m;
152
153 if (fin->fin_v != 4)
154 return -1;
155
156 off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
157 bzero(softi->ipsec_buffer, sizeof(softi->ipsec_buffer));
158 ip = fin->fin_ip;
159 m = fin->fin_m;
160
161 dlen = M_LEN(m) - off;
162 if (dlen < 16)
163 return -1;
164 COPYDATA(m, off, MIN(sizeof(softi->ipsec_buffer), dlen),
165 softi->ipsec_buffer);
166
167 if (ipf_nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_nsrcip,
168 ip->ip_dst) != NULL)
169 return -1;
170
171 np = nat->nat_ptr;
172 size = np->in_size;
173 KMALLOC(ipsec, ipsec_pxy_t *);
174 if (ipsec == NULL)
175 return -1;
176
177 KMALLOCS(ipn, ipnat_t *, size);
178 if (ipn == NULL) {
179 KFREE(ipsec);
180 return -1;
181 }
182
183 aps->aps_data = ipsec;
184 aps->aps_psiz = sizeof(*ipsec);
185 bzero((char *)ipsec, sizeof(*ipsec));
186 bzero((char *)ipn, size);
187 ipsec->ipsc_rule = ipn;
188
189 /*
190 * Create NAT rule against which the tunnel/transport mapping is
191 * created. This is required because the current NAT rule does not
192 * describe ESP but UDP instead.
193 */
194 ipn->in_size = size;
195 ttl = IPF_TTLVAL(softi->ipsec_nat_tqe->ifq_ttl);
196 ipn->in_tqehead[0] = ipf_nat_add_tq(softc, ttl);
197 ipn->in_tqehead[1] = ipf_nat_add_tq(softc, ttl);
198 ipn->in_ifps[0] = fin->fin_ifp;
199 ipn->in_apr = NULL;
200 ipn->in_use = 1;
201 ipn->in_hits = 1;
202 ipn->in_snip = ntohl(nat->nat_nsrcaddr);
203 ipn->in_ippip = 1;
204 ipn->in_osrcip = nat->nat_osrcip;
205 ipn->in_osrcmsk = 0xffffffff;
206 ipn->in_nsrcip = nat->nat_nsrcip;
207 ipn->in_nsrcmsk = 0xffffffff;
208 ipn->in_odstip = nat->nat_odstip;
209 ipn->in_odstmsk = 0xffffffff;
210 ipn->in_ndstip = nat->nat_ndstip;
211 ipn->in_ndstmsk = 0xffffffff;
212 ipn->in_redir = NAT_MAP;
213 ipn->in_pr[0] = IPPROTO_ESP;
214 ipn->in_pr[1] = IPPROTO_ESP;
215 ipn->in_flags = (np->in_flags | IPN_PROXYRULE);
216 MUTEX_INIT(&ipn->in_lock, "IPSec proxy NAT rule");
217
218 ipn->in_namelen = np->in_namelen;
219 bcopy(np->in_names, ipn->in_ifnames, ipn->in_namelen);
220 ipn->in_ifnames[0] = np->in_ifnames[0];
221 ipn->in_ifnames[1] = np->in_ifnames[1];
222
223 bcopy((char *)fin, (char *)&fi, sizeof(fi));
224 fi.fin_fi.fi_p = IPPROTO_ESP;
225 fi.fin_fr = &softi->ipsec_fr;
226 fi.fin_data[0] = 0;
227 fi.fin_data[1] = 0;
228 p = ip->ip_p;
229 ip->ip_p = IPPROTO_ESP;
230 fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
231 fi.fin_flx |= FI_IGNORE;
232
233 ptr = softi->ipsec_buffer;
234 bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
235 ptr += sizeof(ipsec_cookie_t);
236 bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
237 /*
238 * The responder cookie should only be non-zero if the initiator
239 * cookie is non-zero. Therefore, it is safe to assume(!) that the
240 * cookies are both set after copying if the responder is non-zero.
241 */
242 if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
243 ipsec->ipsc_rckset = 1;
244
245 MUTEX_ENTER(&softn->ipf_nat_new);
246 ipsec->ipsc_nat = ipf_nat_add(&fi, ipn, &ipsec->ipsc_nat,
247 NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
248 MUTEX_EXIT(&softn->ipf_nat_new);
249 if (ipsec->ipsc_nat != NULL) {
250 (void) ipf_nat_proto(&fi, ipsec->ipsc_nat, 0);
251 MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock);
252 ipf_nat_update(&fi, ipsec->ipsc_nat);
253 MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock);
254
255 fi.fin_data[0] = 0;
256 fi.fin_data[1] = 0;
257 (void) ipf_state_add(softc, &fi, &ipsec->ipsc_state, SI_WILDP);
258 }
259 ip->ip_p = p & 0xff;
260 return 0;
261 }
262
263
264 /*
265 * For outgoing IKE packets. refresh timeouts for NAT & state entries, if
266 * we can. If they have disappeared, recreate them.
267 */
268 int
ipf_p_ipsec_inout(arg,fin,aps,nat)269 ipf_p_ipsec_inout(arg, fin, aps, nat)
270 void *arg;
271 fr_info_t *fin;
272 ap_session_t *aps;
273 nat_t *nat;
274 {
275 ipf_ipsec_softc_t *softi = arg;
276 ipf_main_softc_t *softc = fin->fin_main_soft;
277 ipsec_pxy_t *ipsec;
278 fr_info_t fi;
279 ip_t *ip;
280 int p;
281
282 if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND))
283 return 0;
284
285 if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND))
286 return 0;
287
288 ipsec = aps->aps_data;
289
290 if (ipsec != NULL) {
291 ip = fin->fin_ip;
292 p = ip->ip_p;
293
294 if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) {
295 bcopy((char *)fin, (char *)&fi, sizeof(fi));
296 fi.fin_fi.fi_p = IPPROTO_ESP;
297 fi.fin_fr = &softi->ipsec_fr;
298 fi.fin_data[0] = 0;
299 fi.fin_data[1] = 0;
300 ip->ip_p = IPPROTO_ESP;
301 fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
302 fi.fin_flx |= FI_IGNORE;
303 }
304
305 /*
306 * Update NAT timeout/create NAT if missing.
307 */
308 if (ipsec->ipsc_nat != NULL)
309 ipf_queueback(softc->ipf_ticks,
310 &ipsec->ipsc_nat->nat_tqe);
311 else {
312 #ifdef USE_MUTEXES
313 ipf_nat_softc_t *softn = softc->ipf_nat_soft;
314 #endif
315
316 MUTEX_ENTER(&softn->ipf_nat_new);
317 ipsec->ipsc_nat = ipf_nat_add(&fi, ipsec->ipsc_rule,
318 &ipsec->ipsc_nat,
319 NAT_SLAVE|SI_WILDP,
320 nat->nat_dir);
321 MUTEX_EXIT(&softn->ipf_nat_new);
322 if (ipsec->ipsc_nat != NULL) {
323 (void) ipf_nat_proto(&fi, ipsec->ipsc_nat, 0);
324 MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock);
325 ipf_nat_update(&fi, ipsec->ipsc_nat);
326 MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock);
327 }
328 }
329
330 /*
331 * Update state timeout/create state if missing.
332 */
333 READ_ENTER(&softc->ipf_state);
334 if (ipsec->ipsc_state != NULL) {
335 ipf_queueback(softc->ipf_ticks,
336 &ipsec->ipsc_state->is_sti);
337 ipsec->ipsc_state->is_die = nat->nat_age;
338 RWLOCK_EXIT(&softc->ipf_state);
339 } else {
340 RWLOCK_EXIT(&softc->ipf_state);
341 fi.fin_data[0] = 0;
342 fi.fin_data[1] = 0;
343 (void) ipf_state_add(softc, &fi, &ipsec->ipsc_state,
344 SI_WILDP);
345 }
346 ip->ip_p = p;
347 }
348 return 0;
349 }
350
351
352 /*
353 * This extends the NAT matching to be based on the cookies associated with
354 * a session and found at the front of IKE packets. The cookies are always
355 * in the same order (not reversed depending on packet flow direction as with
356 * UDP/TCP port numbers).
357 */
358 int
ipf_p_ipsec_match(fin,aps,nat)359 ipf_p_ipsec_match(fin, aps, nat)
360 fr_info_t *fin;
361 ap_session_t *aps;
362 nat_t *nat;
363 {
364 ipsec_pxy_t *ipsec;
365 u_32_t cookies[4];
366 mb_t *m;
367 int off;
368
369 nat = nat; /* LINT */
370
371 if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG))
372 return -1;
373
374 off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
375 ipsec = aps->aps_data;
376 m = fin->fin_m;
377 COPYDATA(m, off, sizeof(cookies), (char *)cookies);
378
379 if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
380 (cookies[1] != ipsec->ipsc_icookie[1]))
381 return -1;
382
383 if (ipsec->ipsc_rckset == 0) {
384 if ((cookies[2]|cookies[3]) == 0) {
385 return 0;
386 }
387 ipsec->ipsc_rckset = 1;
388 ipsec->ipsc_rcookie[0] = cookies[2];
389 ipsec->ipsc_rcookie[1] = cookies[3];
390 return 0;
391 }
392
393 if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
394 (cookies[3] != ipsec->ipsc_rcookie[1]))
395 return -1;
396 return 0;
397 }
398
399
400 /*
401 * clean up after ourselves.
402 */
403 void
ipf_p_ipsec_del(softc,aps)404 ipf_p_ipsec_del(softc, aps)
405 ipf_main_softc_t *softc;
406 ap_session_t *aps;
407 {
408 ipsec_pxy_t *ipsec;
409
410 ipsec = aps->aps_data;
411
412 if (ipsec != NULL) {
413 /*
414 * Don't bother changing any of the NAT structure details,
415 * *_del() is on a callback from aps_free(), from nat_delete()
416 */
417
418 READ_ENTER(&softc->ipf_state);
419 if (ipsec->ipsc_state != NULL) {
420 ipsec->ipsc_state->is_die = softc->ipf_ticks + 1;
421 ipsec->ipsc_state->is_me = NULL;
422 ipf_queuefront(&ipsec->ipsc_state->is_sti);
423 }
424 RWLOCK_EXIT(&softc->ipf_state);
425
426 ipsec->ipsc_state = NULL;
427 ipsec->ipsc_nat = NULL;
428 ipsec->ipsc_rule->in_flags |= IPN_DELETE;
429 ipf_nat_rule_deref(softc, &ipsec->ipsc_rule);
430 }
431 }
432