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