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xform_tcp.c (302408) xform_tcp.c (315514)
1/* $FreeBSD: stable/11/sys/netipsec/xform_tcp.c 302054 2016-06-21 13:48:49Z bz $ */
2
3/*-
4 * Copyright (c) 2003 Bruce M. Simpson <bms@spc.org>
1/*-
2 * Copyright (c) 2003 Bruce M. Simpson <bms@spc.org>
3 * Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright

--- 10 unchanged lines hidden (view full) ---

23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30/* TCP MD5 Signature Option (RFC2385) */
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright

--- 10 unchanged lines hidden (view full) ---

22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/* TCP MD5 Signature Option (RFC2385) */
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: stable/11/sys/netipsec/xform_tcp.c 315514 2017-03-18 22:04:20Z ae $");
32
31#include "opt_inet.h"
32#include "opt_inet6.h"
33#include "opt_inet.h"
34#include "opt_inet6.h"
35#include "opt_ipsec.h"
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/mbuf.h>
37#include <sys/lock.h>
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/mbuf.h>
40#include <sys/lock.h>
41#include <sys/md5.h>
42#include <sys/rmlock.h>
38#include <sys/socket.h>
43#include <sys/socket.h>
44#include <sys/sockopt.h>
39#include <sys/kernel.h>
45#include <sys/kernel.h>
46#include <sys/module.h>
40#include <sys/protosw.h>
47#include <sys/protosw.h>
41#include <sys/sysctl.h>
42
43#include <netinet/in.h>
48
49#include <netinet/in.h>
50#include <netinet/in_pcb.h>
44#include <netinet/in_systm.h>
45#include <netinet/ip.h>
46#include <netinet/ip_var.h>
47#include <netinet/tcp.h>
48#include <netinet/tcp_var.h>
49
50#include <net/vnet.h>
51
52#include <netipsec/ipsec.h>
51#include <netinet/in_systm.h>
52#include <netinet/ip.h>
53#include <netinet/ip_var.h>
54#include <netinet/tcp.h>
55#include <netinet/tcp_var.h>
56
57#include <net/vnet.h>
58
59#include <netipsec/ipsec.h>
60#include <netipsec/ipsec_support.h>
53#include <netipsec/xform.h>
54
55#ifdef INET6
56#include <netinet/ip6.h>
57#include <netipsec/ipsec6.h>
58#endif
59
60#include <netipsec/key.h>
61#include <netipsec/key_debug.h>
62
61#include <netipsec/xform.h>
62
63#ifdef INET6
64#include <netinet/ip6.h>
65#include <netipsec/ipsec6.h>
66#endif
67
68#include <netipsec/key.h>
69#include <netipsec/key_debug.h>
70
71#define TCP_SIGLEN 16 /* length of computed digest in bytes */
72#define TCP_KEYLEN_MIN 1 /* minimum length of TCP-MD5 key */
73#define TCP_KEYLEN_MAX 80 /* maximum length of TCP-MD5 key */
74
75static int
76tcp_ipsec_pcbctl(struct inpcb *inp, struct sockopt *sopt)
77{
78 struct tcpcb *tp;
79 int error, optval;
80
81 INP_WLOCK_ASSERT(inp);
82 if (sopt->sopt_name != TCP_MD5SIG) {
83 INP_WUNLOCK(inp);
84 return (ENOPROTOOPT);
85 }
86
87 tp = intotcpcb(inp);
88 if (sopt->sopt_dir == SOPT_GET) {
89 optval = (tp->t_flags & TF_SIGNATURE) ? 1 : 0;
90 INP_WUNLOCK(inp);
91
92 /* On success return with released INP_WLOCK */
93 return (sooptcopyout(sopt, &optval, sizeof(optval)));
94 }
95
96 INP_WUNLOCK(inp);
97
98 error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
99 if (error != 0)
100 return (error);
101
102 /* INP_WLOCK_RECHECK */
103 INP_WLOCK(inp);
104 if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
105 INP_WUNLOCK(inp);
106 return (ECONNRESET);
107 }
108 if (optval > 0)
109 tp->t_flags |= TF_SIGNATURE;
110 else
111 tp->t_flags &= ~TF_SIGNATURE;
112
113 /* On success return with acquired INP_WLOCK */
114 return (error);
115}
116
63/*
117/*
118 * Callback function invoked by m_apply() to digest TCP segment data
119 * contained within an mbuf chain.
120 */
121static int
122tcp_signature_apply(void *fstate, void *data, u_int len)
123{
124
125 MD5Update(fstate, (u_char *)data, len);
126 return (0);
127}
128
129#ifdef INET
130static int
131ip_pseudo_compute(struct mbuf *m, MD5_CTX *ctx)
132{
133 struct ippseudo ipp;
134 struct ip *ip;
135
136 ip = mtod(m, struct ip *);
137 ipp.ippseudo_src.s_addr = ip->ip_src.s_addr;
138 ipp.ippseudo_dst.s_addr = ip->ip_dst.s_addr;
139 ipp.ippseudo_p = IPPROTO_TCP;
140 ipp.ippseudo_pad = 0;
141 ipp.ippseudo_len = htons(m->m_pkthdr.len - (ip->ip_hl << 2));
142 MD5Update(ctx, (char *)&ipp, sizeof(ipp));
143 return (ip->ip_hl << 2);
144}
145#endif
146
147#ifdef INET6
148static int
149ip6_pseudo_compute(struct mbuf *m, MD5_CTX *ctx)
150{
151 struct ip6_pseudo {
152 struct in6_addr src, dst;
153 uint32_t len;
154 uint32_t nxt;
155 } ip6p __aligned(4);
156 struct ip6_hdr *ip6;
157
158 ip6 = mtod(m, struct ip6_hdr *);
159 ip6p.src = ip6->ip6_src;
160 ip6p.dst = ip6->ip6_dst;
161 ip6p.len = htonl(m->m_pkthdr.len - sizeof(*ip6)); /* XXX: ext headers */
162 ip6p.nxt = htonl(IPPROTO_TCP);
163 MD5Update(ctx, (char *)&ip6p, sizeof(ip6p));
164 return (sizeof(*ip6));
165}
166#endif
167
168static int
169tcp_signature_compute(struct mbuf *m, struct tcphdr *th,
170 struct secasvar *sav, u_char *buf)
171{
172 MD5_CTX ctx;
173 int len;
174 u_short csum;
175
176 MD5Init(&ctx);
177 /* Step 1: Update MD5 hash with IP(v6) pseudo-header. */
178 switch (sav->sah->saidx.dst.sa.sa_family) {
179#ifdef INET
180 case AF_INET:
181 len = ip_pseudo_compute(m, &ctx);
182 break;
183#endif
184#ifdef INET6
185 case AF_INET6:
186 len = ip6_pseudo_compute(m, &ctx);
187 break;
188#endif
189 default:
190 return (EAFNOSUPPORT);
191 }
192 /*
193 * Step 2: Update MD5 hash with TCP header, excluding options.
194 * The TCP checksum must be set to zero.
195 */
196 csum = th->th_sum;
197 th->th_sum = 0;
198 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr));
199 th->th_sum = csum;
200 /*
201 * Step 3: Update MD5 hash with TCP segment data.
202 * Use m_apply() to avoid an early m_pullup().
203 */
204 len += (th->th_off << 2);
205 if (m->m_pkthdr.len - len > 0)
206 m_apply(m, len, m->m_pkthdr.len - len,
207 tcp_signature_apply, &ctx);
208 /*
209 * Step 4: Update MD5 hash with shared secret.
210 */
211 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth));
212 MD5Final(buf, &ctx);
213 key_sa_recordxfer(sav, m);
214 return (0);
215}
216
217static void
218setsockaddrs(const struct mbuf *m, union sockaddr_union *src,
219 union sockaddr_union *dst)
220{
221 struct ip *ip;
222
223 IPSEC_ASSERT(m->m_len >= sizeof(*ip), ("unexpected mbuf len"));
224
225 ip = mtod(m, struct ip *);
226 switch (ip->ip_v) {
227#ifdef INET
228 case IPVERSION:
229 ipsec4_setsockaddrs(m, src, dst);
230 break;
231#endif
232#ifdef INET6
233 case (IPV6_VERSION >> 4):
234 ipsec6_setsockaddrs(m, src, dst);
235 break;
236#endif
237 default:
238 bzero(src, sizeof(*src));
239 bzero(dst, sizeof(*dst));
240 }
241}
242
243/*
244 * Compute TCP-MD5 hash of an *INBOUND* TCP segment.
245 * Parameters:
246 * m pointer to head of mbuf chain
247 * th pointer to TCP header
248 * buf pointer to storage for computed MD5 digest
249 *
250 * Return 0 if successful, otherwise return -1.
251 */
252static int
253tcp_ipsec_input(struct mbuf *m, struct tcphdr *th, u_char *buf)
254{
255 char tmpdigest[TCP_SIGLEN];
256 struct secasindex saidx;
257 struct secasvar *sav;
258
259 setsockaddrs(m, &saidx.src, &saidx.dst);
260 saidx.proto = IPPROTO_TCP;
261 saidx.mode = IPSEC_MODE_TCPMD5;
262 saidx.reqid = 0;
263 sav = key_allocsa_tcpmd5(&saidx);
264 if (sav == NULL) {
265 KMOD_TCPSTAT_INC(tcps_sig_err_buildsig);
266 return (EACCES);
267 }
268 /*
269 * tcp_input() operates with TCP header fields in host
270 * byte order. We expect them in network byte order.
271 */
272 tcp_fields_to_net(th);
273 tcp_signature_compute(m, th, sav, tmpdigest);
274 tcp_fields_to_host(th);
275 key_freesav(&sav);
276 if (bcmp(buf, tmpdigest, TCP_SIGLEN) != 0) {
277 KMOD_TCPSTAT_INC(tcps_sig_rcvbadsig);
278 return (EACCES);
279 }
280 KMOD_TCPSTAT_INC(tcps_sig_rcvgoodsig);
281 return (0);
282}
283
284/*
285 * Compute TCP-MD5 hash of an *OUTBOUND* TCP segment.
286 * Parameters:
287 * m pointer to head of mbuf chain
288 * th pointer to TCP header
289 * buf pointer to storage for computed MD5 digest
290 *
291 * Return 0 if successful, otherwise return error code.
292 */
293static int
294tcp_ipsec_output(struct mbuf *m, struct tcphdr *th, u_char *buf)
295{
296 struct secasindex saidx;
297 struct secasvar *sav;
298
299 setsockaddrs(m, &saidx.src, &saidx.dst);
300 saidx.proto = IPPROTO_TCP;
301 saidx.mode = IPSEC_MODE_TCPMD5;
302 saidx.reqid = 0;
303 sav = key_allocsa_tcpmd5(&saidx);
304 if (sav == NULL) {
305 KMOD_TCPSTAT_INC(tcps_sig_err_buildsig);
306 return (EACCES);
307 }
308 tcp_signature_compute(m, th, sav, buf);
309 key_freesav(&sav);
310 return (0);
311}
312
313/*
64 * Initialize a TCP-MD5 SA. Called when the SA is being set up.
65 *
66 * We don't need to set up the tdb prefixed fields, as we don't use the
67 * opencrypto code; we just perform a key length check.
68 *
314 * Initialize a TCP-MD5 SA. Called when the SA is being set up.
315 *
316 * We don't need to set up the tdb prefixed fields, as we don't use the
317 * opencrypto code; we just perform a key length check.
318 *
69 * XXX: Currently we only allow a single 'magic' SPI to be used.
319 * XXX: Currently we have used single 'magic' SPI and need to still
320 * support this.
70 *
71 * This allows per-host granularity without affecting the userland
72 * interface, which is a simple socket option toggle switch,
73 * TCP_SIGNATURE_ENABLE.
74 *
75 * To allow per-service granularity requires that we have a means
76 * of mapping port to SPI. The mandated way of doing this is to
77 * use SPD entries to specify packet flows which get the TCP-MD5
78 * treatment, however the code to do this is currently unstable
79 * and unsuitable for production use.
80 *
81 * Therefore we use this compromise in the meantime.
82 */
83static int
84tcpsignature_init(struct secasvar *sav, struct xformsw *xsp)
85{
86 int keylen;
87
321 *
322 * This allows per-host granularity without affecting the userland
323 * interface, which is a simple socket option toggle switch,
324 * TCP_SIGNATURE_ENABLE.
325 *
326 * To allow per-service granularity requires that we have a means
327 * of mapping port to SPI. The mandated way of doing this is to
328 * use SPD entries to specify packet flows which get the TCP-MD5
329 * treatment, however the code to do this is currently unstable
330 * and unsuitable for production use.
331 *
332 * Therefore we use this compromise in the meantime.
333 */
334static int
335tcpsignature_init(struct secasvar *sav, struct xformsw *xsp)
336{
337 int keylen;
338
88 if (sav->spi != htonl(TCP_SIG_SPI)) {
89 DPRINTF(("%s: SPI must be TCP_SIG_SPI (0x1000)\n",
90 __func__));
91 return (EINVAL);
92 }
93 if (sav->alg_auth != SADB_X_AALG_TCP_MD5) {
94 DPRINTF(("%s: unsupported authentication algorithm %u\n",
95 __func__, sav->alg_auth));
96 return (EINVAL);
97 }
98 if (sav->key_auth == NULL) {
99 DPRINTF(("%s: no authentication key present\n", __func__));
100 return (EINVAL);
101 }
102 keylen = _KEYLEN(sav->key_auth);
103 if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) {
104 DPRINTF(("%s: invalid key length %u\n", __func__, keylen));
105 return (EINVAL);
106 }
339 if (sav->alg_auth != SADB_X_AALG_TCP_MD5) {
340 DPRINTF(("%s: unsupported authentication algorithm %u\n",
341 __func__, sav->alg_auth));
342 return (EINVAL);
343 }
344 if (sav->key_auth == NULL) {
345 DPRINTF(("%s: no authentication key present\n", __func__));
346 return (EINVAL);
347 }
348 keylen = _KEYLEN(sav->key_auth);
349 if ((keylen < TCP_KEYLEN_MIN) || (keylen > TCP_KEYLEN_MAX)) {
350 DPRINTF(("%s: invalid key length %u\n", __func__, keylen));
351 return (EINVAL);
352 }
107
353 sav->tdb_xform = xsp;
108 return (0);
109}
110
111/*
354 return (0);
355}
356
357/*
112 * Paranoia.
113 *
114 * Called when the SA is deleted.
115 */
116static int
117tcpsignature_zeroize(struct secasvar *sav)
118{
119
358 * Called when the SA is deleted.
359 */
360static int
361tcpsignature_zeroize(struct secasvar *sav)
362{
363
120 if (sav->key_auth)
364 if (sav->key_auth != NULL)
121 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
365 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
122
123 sav->tdb_cryptoid = 0;
124 sav->tdb_authalgxform = NULL;
125 sav->tdb_xform = NULL;
366 sav->tdb_xform = NULL;
126
127 return (0);
128}
129
367 return (0);
368}
369
130/*
131 * Verify that an input packet passes authentication.
132 * Called from the ipsec layer.
133 * We do this from within tcp itself, so this routine is just a stub.
134 */
135static int
136tcpsignature_input(struct mbuf *m, struct secasvar *sav, int skip,
137 int protoff)
138{
370static struct xformsw tcpsignature_xformsw = {
371 .xf_type = XF_TCPSIGNATURE,
372 .xf_name = "TCP-MD5",
373 .xf_init = tcpsignature_init,
374 .xf_zeroize = tcpsignature_zeroize,
375};
139
376
140 return (0);
141}
377static const struct tcpmd5_methods tcpmd5_methods = {
378 .input = tcp_ipsec_input,
379 .output = tcp_ipsec_output,
380 .pcbctl = tcp_ipsec_pcbctl,
381};
142
382
143/*
144 * Prepend the authentication header.
145 * Called from the ipsec layer.
146 * We do this from within tcp itself, so this routine is just a stub.
147 */
383#ifndef KLD_MODULE
384/* TCP-MD5 support is build in the kernel */
385static const struct tcpmd5_support tcpmd5_ipsec = {
386 .enabled = IPSEC_MODULE_ENABLED,
387 .methods = &tcpmd5_methods
388};
389const struct tcpmd5_support * const tcp_ipsec_support = &tcpmd5_ipsec;
390#endif /* !KLD_MODULE */
391
148static int
392static int
149tcpsignature_output(struct mbuf *m, struct ipsecrequest *isr,
150 struct mbuf **mp, int skip, int protoff)
393tcpmd5_modevent(module_t mod, int type, void *data)
151{
152
394{
395
153 return (EINVAL);
396 switch (type) {
397 case MOD_LOAD:
398 xform_attach(&tcpsignature_xformsw);
399#ifdef KLD_MODULE
400 tcpmd5_support_enable(&tcpmd5_methods);
401#endif
402 break;
403 case MOD_UNLOAD:
404#ifdef KLD_MODULE
405 tcpmd5_support_disable();
406#endif
407 xform_detach(&tcpsignature_xformsw);
408 break;
409 default:
410 return (EOPNOTSUPP);
411 }
412 return (0);
154}
155
413}
414
156static struct xformsw tcpsignature_xformsw = {
157 XF_TCPSIGNATURE, XFT_AUTH, "TCPMD5",
158 tcpsignature_init, tcpsignature_zeroize,
159 tcpsignature_input, tcpsignature_output
415static moduledata_t tcpmd5_mod = {
416 "tcpmd5",
417 tcpmd5_modevent,
418 0
160};
161
419};
420
162static void
163tcpsignature_attach(void)
164{
165
166 xform_register(&tcpsignature_xformsw);
167}
168
169SYSINIT(tcpsignature_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
170 tcpsignature_attach, NULL);
421DECLARE_MODULE(tcpmd5, tcpmd5_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
422MODULE_VERSION(tcpmd5, 1);
423#ifdef KLD_MODULE
424MODULE_DEPEND(tcpmd5, ipsec_support, 1, 1, 1);
425#endif