xref: /illumos-gate/usr/src/uts/common/inet/ipf/netinet/ip_ipsec_pxy.c (revision 33f2fefd46350ca5992567761c46a5b70f864340)
1 /*
2  * Copyright (C) 2001-2003 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: ip_ipsec_pxy.c,v 2.20.2.7 2005/07/15 21:56:50 darrenr Exp $
10  *
11  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
12  * Use is subject to license terms.
13  */
14 
15 #define	IPF_IPSEC_PROXY
16 
17 typedef struct ifs_ipsecpxy {
18 	frentry_t		ipsecfr;
19 	ipftq_t			*ipsecnattqe;
20 	ipftq_t			*ipsecstatetqe;
21 	char			ipsec_buffer[1500];
22 	int			ipsec_proxy_init;
23 	int			ipsec_proxy_ttl;
24 } ifs_ipsecpxy_t;
25 
26 int ippr_ipsec_init __P((void **, ipf_stack_t *));
27 void ippr_ipsec_fini __P((void **, ipf_stack_t *));
28 int ippr_ipsec_new __P((fr_info_t *, ap_session_t *, nat_t *, void *));
29 void ippr_ipsec_del __P((ap_session_t *, void *, ipf_stack_t *));
30 int ippr_ipsec_inout __P((fr_info_t *, ap_session_t *, nat_t *, void *));
31 int ippr_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *, void *));
32 
33 /*
34  * IPSec application proxy initialization.
35  */
ippr_ipsec_init(private,ifs)36 int ippr_ipsec_init(private, ifs)
37 void **private;
38 ipf_stack_t *ifs;
39 {
40 	ifs_ipsecpxy_t *ifsipsec;
41 
42 	KMALLOC(ifsipsec, ifs_ipsecpxy_t *);
43 	if (ifsipsec == NULL)
44 		return -1;
45 
46 	bzero((char *)&ifsipsec->ipsecfr, sizeof(ifsipsec->ipsecfr));
47 	ifsipsec->ipsecfr.fr_ref = 1;
48 	ifsipsec->ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
49 	MUTEX_INIT(&ifsipsec->ipsecfr.fr_lock, "IPsec proxy rule lock");
50 	ifsipsec->ipsec_proxy_init = 1;
51 	ifsipsec->ipsec_proxy_ttl = 60;
52 
53 	ifsipsec->ipsecnattqe = fr_addtimeoutqueue(&ifs->ifs_nat_utqe, ifsipsec->ipsec_proxy_ttl, ifs);
54 	if (ifsipsec->ipsecnattqe == NULL) {
55 		MUTEX_DESTROY(&ifsipsec->ipsecfr.fr_lock);
56 		KFREE(ifsipsec);
57 		return -1;
58 	}
59 	ifsipsec->ipsecstatetqe = fr_addtimeoutqueue(&ifs->ifs_ips_utqe, ifsipsec->ipsec_proxy_ttl, ifs);
60 	if (ifsipsec->ipsecstatetqe == NULL) {
61 		if (fr_deletetimeoutqueue(ifsipsec->ipsecnattqe) == 0)
62 			fr_freetimeoutqueue(ifsipsec->ipsecnattqe, ifs);
63 		ifsipsec->ipsecnattqe = NULL;
64 		MUTEX_DESTROY(&ifsipsec->ipsecfr.fr_lock);
65 		KFREE(ifsipsec);
66 		return -1;
67 	}
68 
69 	ifsipsec->ipsecnattqe->ifq_flags |= IFQF_PROXY;
70 	ifsipsec->ipsecstatetqe->ifq_flags |= IFQF_PROXY;
71 
72 	ifsipsec->ipsecfr.fr_age[0] = ifsipsec->ipsec_proxy_ttl;
73 	ifsipsec->ipsecfr.fr_age[1] = ifsipsec->ipsec_proxy_ttl;
74 
75 	*private = (void *)ifsipsec;
76 
77 	return 0;
78 }
79 
80 
ippr_ipsec_fini(private,ifs)81 void ippr_ipsec_fini(private, ifs)
82 void **private;
83 ipf_stack_t *ifs;
84 {
85 	ifs_ipsecpxy_t *ifsipsec = *((ifs_ipsecpxy_t **)private);
86 
87 	if (ifsipsec->ipsecnattqe != NULL) {
88 		if (fr_deletetimeoutqueue(ifsipsec->ipsecnattqe) == 0)
89 			fr_freetimeoutqueue(ifsipsec->ipsecnattqe, ifs);
90 	}
91 	ifsipsec->ipsecnattqe = NULL;
92 	if (ifsipsec->ipsecstatetqe != NULL) {
93 		if (fr_deletetimeoutqueue(ifsipsec->ipsecstatetqe) == 0)
94 			fr_freetimeoutqueue(ifsipsec->ipsecstatetqe, ifs);
95 	}
96 	ifsipsec->ipsecstatetqe = NULL;
97 
98 	if (ifsipsec->ipsec_proxy_init == 1) {
99 		MUTEX_DESTROY(&ifsipsec->ipsecfr.fr_lock);
100 		ifsipsec->ipsec_proxy_init = 0;
101 	}
102 
103 	KFREE(ifsipsec);
104 	*private = NULL;
105 }
106 
107 
108 /*
109  * Setup for a new IPSEC proxy.
110  */
ippr_ipsec_new(fin,aps,nat,private)111 int ippr_ipsec_new(fin, aps, nat, private)
112 fr_info_t *fin;
113 ap_session_t *aps;
114 nat_t *nat;
115 void *private;
116 {
117 	ipsec_pxy_t *ipsec;
118 	fr_info_t fi;
119 	ipnat_t *ipn;
120 	char *ptr;
121 	int p, off, dlen, ttl;
122 	mb_t *m;
123 	ip_t *ip;
124 	ipf_stack_t *ifs = fin->fin_ifs;
125 	ifs_ipsecpxy_t *ifsipsec = (ifs_ipsecpxy_t *)private;
126 
127 	off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
128 	bzero(ifsipsec->ipsec_buffer, sizeof(ifsipsec->ipsec_buffer));
129 	ip = fin->fin_ip;
130 	m = fin->fin_m;
131 
132 	dlen = M_LEN(m) - off;
133 	if (dlen < 16)
134 		return -1;
135 	COPYDATA(m, off, MIN(sizeof(ifsipsec->ipsec_buffer), dlen),
136 		 ifsipsec->ipsec_buffer);
137 
138 	if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
139 			  ip->ip_dst) != NULL)
140 		return -1;
141 
142 	aps->aps_psiz = sizeof(*ipsec);
143 	KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
144 	if (aps->aps_data == NULL)
145 		return -1;
146 
147 	ipsec = aps->aps_data;
148 	bzero((char *)ipsec, sizeof(*ipsec));
149 
150 	/*
151 	 * Create NAT rule against which the tunnel/transport mapping is
152 	 * created.  This is required because the current NAT rule does not
153 	 * describe ESP but UDP instead.
154 	 */
155 	ipn = &ipsec->ipsc_rule;
156 	ttl = IPF_TTLVAL(ifsipsec->ipsecnattqe->ifq_ttl);
157 	ipn->in_tqehead[0] = fr_addtimeoutqueue(&ifs->ifs_nat_utqe, ttl, ifs);
158 	ipn->in_tqehead[1] = fr_addtimeoutqueue(&ifs->ifs_nat_utqe, ttl, ifs);
159 	ipn->in_ifps[0] = fin->fin_ifp;
160 	ipn->in_apr = NULL;
161 	ipn->in_use = 1;
162 	ipn->in_hits = 1;
163 	ipn->in_nip = ntohl(nat->nat_outip.s_addr);
164 	ipn->in_ippip = 1;
165 	ipn->in_inip = nat->nat_inip.s_addr;
166 	ipn->in_inmsk = 0xffffffff;
167 	ipn->in_outip = fin->fin_saddr;
168 	ipn->in_outmsk = nat->nat_outip.s_addr;
169 	ipn->in_srcip = fin->fin_saddr;
170 	ipn->in_srcmsk = 0xffffffff;
171 	ipn->in_redir = NAT_MAP;
172 	bcopy(nat->nat_ptr->in_ifnames[0], ipn->in_ifnames[0],
173 	      sizeof(ipn->in_ifnames[0]));
174 	ipn->in_p = IPPROTO_ESP;
175 
176 	bcopy((char *)fin, (char *)&fi, sizeof(fi));
177 	fi.fin_fi.fi_p = IPPROTO_ESP;
178 	fi.fin_fr = &ifsipsec->ipsecfr;
179 	fi.fin_data[0] = 0;
180 	fi.fin_data[1] = 0;
181 	p = ip->ip_p;
182 	ip->ip_p = IPPROTO_ESP;
183 	fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
184 	fi.fin_flx |= FI_IGNORE;
185 
186 	ptr = ifsipsec->ipsec_buffer;
187 	bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
188 	ptr += sizeof(ipsec_cookie_t);
189 	bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
190 	/*
191 	 * The responder cookie should only be non-zero if the initiator
192 	 * cookie is non-zero.  Therefore, it is safe to assume(!) that the
193 	 * cookies are both set after copying if the responder is non-zero.
194 	 */
195 	if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
196 		ipsec->ipsc_rckset = 1;
197 
198 	ipsec->ipsc_nat = nat_new(&fi, ipn, &ipsec->ipsc_nat,
199 				  NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
200 	if (ipsec->ipsc_nat != NULL) {
201 		(void) nat_proto(&fi, ipsec->ipsc_nat, 0);
202 		nat_update(&fi, ipsec->ipsc_nat, ipn);
203 
204 		fi.fin_data[0] = 0;
205 		fi.fin_data[1] = 0;
206 		ipsec->ipsc_state = fr_addstate(&fi, &ipsec->ipsc_state,
207 						SI_WILDP);
208 	}
209 	ip->ip_p = p & 0xff;
210 	return 0;
211 }
212 
213 
214 /*
215  * For outgoing IKE packets.  refresh timeouts for NAT & state entries, if
216  * we can.  If they have disappeared, recreate them.
217  */
ippr_ipsec_inout(fin,aps,nat,private)218 int ippr_ipsec_inout(fin, aps, nat, private)
219 fr_info_t *fin;
220 ap_session_t *aps;
221 nat_t *nat;
222 void *private;
223 {
224 	ipsec_pxy_t *ipsec;
225 	fr_info_t fi;
226 	ip_t *ip;
227 	int p;
228 	ipf_stack_t *ifs = fin->fin_ifs;
229 	ifs_ipsecpxy_t *ifsipsec = (ifs_ipsecpxy_t *)private;
230 
231 	if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND))
232 		return 0;
233 
234 	if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND))
235 		return 0;
236 
237 	ipsec = aps->aps_data;
238 
239 	if (ipsec != NULL) {
240 		ip = fin->fin_ip;
241 		p = ip->ip_p;
242 
243 		if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) {
244 			bcopy((char *)fin, (char *)&fi, sizeof(fi));
245 			fi.fin_fi.fi_p = IPPROTO_ESP;
246 			fi.fin_fr = &ifsipsec->ipsecfr;
247 			fi.fin_data[0] = 0;
248 			fi.fin_data[1] = 0;
249 			ip->ip_p = IPPROTO_ESP;
250 			fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
251 			fi.fin_flx |= FI_IGNORE;
252 		}
253 
254 		/*
255 		 * Update NAT timeout/create NAT if missing.
256 		 */
257 		if (ipsec->ipsc_nat != NULL)
258 			fr_queueback(&ipsec->ipsc_nat->nat_tqe, ifs);
259 		else {
260 			ipsec->ipsc_nat = nat_new(&fi, &ipsec->ipsc_rule,
261 						  &ipsec->ipsc_nat,
262 						  NAT_SLAVE|SI_WILDP,
263 						  nat->nat_dir);
264 			if (ipsec->ipsc_nat != NULL) {
265 				(void) nat_proto(&fi, ipsec->ipsc_nat, 0);
266 				nat_update(&fi, ipsec->ipsc_nat,
267 					   &ipsec->ipsc_rule);
268 			}
269 		}
270 
271 		/*
272 		 * Update state timeout/create state if missing.
273 		 */
274 		READ_ENTER(&ifs->ifs_ipf_state);
275 		if (ipsec->ipsc_state != NULL) {
276 			fr_queueback(&ipsec->ipsc_state->is_sti, ifs);
277 			ipsec->ipsc_state->is_die = nat->nat_age;
278 			RWLOCK_EXIT(&ifs->ifs_ipf_state);
279 		} else {
280 			RWLOCK_EXIT(&ifs->ifs_ipf_state);
281 			fi.fin_data[0] = 0;
282 			fi.fin_data[1] = 0;
283 			ipsec->ipsc_state = fr_addstate(&fi,
284 							&ipsec->ipsc_state,
285 							SI_WILDP);
286 		}
287 		ip->ip_p = p;
288 	}
289 	return 0;
290 }
291 
292 
293 /*
294  * This extends the NAT matching to be based on the cookies associated with
295  * a session and found at the front of IKE packets.  The cookies are always
296  * in the same order (not reversed depending on packet flow direction as with
297  * UDP/TCP port numbers).
298  */
299 /*ARGSUSED*/
ippr_ipsec_match(fin,aps,nat,private)300 int ippr_ipsec_match(fin, aps, nat, private)
301 fr_info_t *fin;
302 ap_session_t *aps;
303 nat_t *nat;
304 void *private;
305 {
306 	ipsec_pxy_t *ipsec;
307 	u_32_t cookies[4];
308 	mb_t *m;
309 	int off;
310 
311 	nat = nat;	/* LINT */
312 
313 	if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG))
314 		return -1;
315 
316 	off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
317 	ipsec = aps->aps_data;
318 	m = fin->fin_m;
319 	COPYDATA(m, off, sizeof(cookies), (char *)cookies);
320 
321 	if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
322 	    (cookies[1] != ipsec->ipsc_icookie[1]))
323 		return -1;
324 
325 	if (ipsec->ipsc_rckset == 0) {
326 		if ((cookies[2]|cookies[3]) == 0) {
327 			return 0;
328 		}
329 		ipsec->ipsc_rckset = 1;
330 		ipsec->ipsc_rcookie[0] = cookies[2];
331 		ipsec->ipsc_rcookie[1] = cookies[3];
332 		return 0;
333 	}
334 
335 	if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
336 	    (cookies[3] != ipsec->ipsc_rcookie[1]))
337 		return -1;
338 	return 0;
339 }
340 
341 
342 /*
343  * clean up after ourselves.
344  */
345 /*ARGSUSED*/
ippr_ipsec_del(aps,private,ifs)346 void ippr_ipsec_del(aps, private, ifs)
347 ap_session_t *aps;
348 void *private;
349 ipf_stack_t *ifs;
350 {
351 	ipsec_pxy_t *ipsec;
352 
353 	ipsec = aps->aps_data;
354 
355 	if (ipsec != NULL) {
356 		/*
357 		 * Don't bother changing any of the NAT structure details,
358 		 * *_del() is on a callback from aps_free(), from nat_delete()
359 		 */
360 
361 		READ_ENTER(&ifs->ifs_ipf_state);
362 		if (ipsec->ipsc_state != NULL) {
363 			ipsec->ipsc_state->is_die = ifs->ifs_fr_ticks + 1;
364 			ipsec->ipsc_state->is_me = NULL;
365 			fr_queuefront(&ipsec->ipsc_state->is_sti);
366 		}
367 		RWLOCK_EXIT(&ifs->ifs_ipf_state);
368 
369 		ipsec->ipsc_state = NULL;
370 		ipsec->ipsc_nat = NULL;
371 	}
372 }
373