1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
5 * Authors: Doug Rabson <dfr@rabson.org>
6 * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 /* Modified from the kernel GSSAPI code for RPC-over-TLS. */
31
32 #include <sys/cdefs.h>
33 #include "opt_kern_tls.h"
34
35 #include <sys/param.h>
36 #include <sys/capsicum.h>
37 #include <sys/file.h>
38 #include <sys/filedesc.h>
39 #include <sys/jail.h>
40 #include <sys/kernel.h>
41 #include <sys/lock.h>
42 #include <sys/malloc.h>
43 #include <sys/mbuf.h>
44 #include <sys/mutex.h>
45 #include <sys/priv.h>
46 #include <sys/proc.h>
47 #include <sys/socketvar.h>
48 #include <sys/syscall.h>
49 #include <sys/syscallsubr.h>
50 #include <sys/sysent.h>
51 #include <sys/sysproto.h>
52 #include <sys/tree.h>
53
54 #include <net/vnet.h>
55
56 #include <rpc/rpc.h>
57 #include <rpc/rpc_com.h>
58 #include <rpc/krpc.h>
59 #include <rpc/rpcsec_tls.h>
60
61 #include <vm/vm.h>
62 #include <vm/pmap.h>
63 #include <vm/vm_param.h>
64
65 #include "rpctlscd.h"
66 #include "rpctlssd.h"
67
68 /*
69 * Syscall hooks
70 */
71 static struct syscall_helper_data rpctls_syscalls[] = {
72 SYSCALL_INIT_HELPER(rpctls_syscall),
73 SYSCALL_INIT_LAST
74 };
75
76 static struct opaque_auth rpctls_null_verf;
77
78 KRPC_VNET_DECLARE(uint64_t, svc_vc_tls_handshake_success);
79 KRPC_VNET_DECLARE(uint64_t, svc_vc_tls_handshake_failed);
80
81 static CLIENT *rpctls_connect_handle;
82 static CLIENT *rpctls_server_handle;
83
84 struct upsock {
85 RB_ENTRY(upsock) tree;
86 struct socket *so;
87 union {
88 CLIENT *cl;
89 SVCXPRT *xp;
90 };
91 bool server;
92 };
93
94 static RB_HEAD(upsock_t, upsock) upcall_sockets;
95 static intptr_t
upsock_compare(const struct upsock * a,const struct upsock * b)96 upsock_compare(const struct upsock *a, const struct upsock *b)
97 {
98 return ((intptr_t)((uintptr_t)a->so/2 - (uintptr_t)b->so/2));
99 }
100 RB_GENERATE_STATIC(upsock_t, upsock, tree, upsock_compare);
101 static struct mtx rpctls_lock;
102
103 static enum clnt_stat rpctls_server(SVCXPRT *xprt, uint32_t *flags,
104 uid_t *uid, int *ngrps, gid_t **gids);
105
106 static CLIENT *
rpctls_client_nl_create(const char * group,const rpcprog_t program,const rpcvers_t version)107 rpctls_client_nl_create(const char *group, const rpcprog_t program,
108 const rpcvers_t version)
109 {
110 CLIENT *cl;
111
112 cl = client_nl_create(group, program, version);
113 KASSERT(cl, ("%s: netlink client already exist", __func__));
114 /*
115 * Set the try_count to 1 so that no retries of the RPC occur. Since
116 * it is an upcall to a local daemon, requests should not be lost and
117 * doing one of these RPCs multiple times is not correct. If the
118 * server is not working correctly, the daemon can get stuck in
119 * SSL_connect() trying to read data from the socket during the upcall.
120 * Set a timeout (currently 15sec) and assume the daemon is hung when
121 * the timeout occurs.
122 */
123 clnt_control(cl, CLSET_RETRIES, &(int){1});
124 clnt_control(cl, CLSET_TIMEOUT, &(struct timeval){.tv_sec = 15});
125 clnt_control(cl, CLSET_WAITCHAN, __DECONST(char *, group));
126
127 return (cl);
128 }
129
130 int
rpctls_init(void)131 rpctls_init(void)
132 {
133 int error;
134
135 error = syscall_helper_register(rpctls_syscalls, SY_THR_STATIC_KLD);
136 if (error != 0) {
137 printf("rpctls_init: cannot register syscall\n");
138 return (error);
139 }
140 mtx_init(&rpctls_lock, "rpctls lock", NULL, MTX_DEF);
141 rpctls_null_verf.oa_flavor = AUTH_NULL;
142 rpctls_null_verf.oa_base = RPCTLS_START_STRING;
143 rpctls_null_verf.oa_length = strlen(RPCTLS_START_STRING);
144 rpctls_connect_handle = rpctls_client_nl_create("tlsclnt",
145 RPCTLSCD, RPCTLSCDVERS);
146 rpctls_server_handle = rpctls_client_nl_create("tlsserv",
147 RPCTLSSD, RPCTLSSDVERS);
148 return (0);
149 }
150
151 int
sys_rpctls_syscall(struct thread * td,struct rpctls_syscall_args * uap)152 sys_rpctls_syscall(struct thread *td, struct rpctls_syscall_args *uap)
153 {
154 struct file *fp;
155 struct upsock *upsp, ups;
156 int fd = -1, error;
157
158 error = priv_check(td, PRIV_NFS_DAEMON);
159 if (error != 0)
160 return (error);
161
162 KRPC_CURVNET_SET(KRPC_TD_TO_VNET(td));
163 mtx_lock(&rpctls_lock);
164 upsp = RB_FIND(upsock_t, &upcall_sockets,
165 &(struct upsock){
166 .so = __DECONST(struct socket *, uap->socookie) });
167 if (__predict_true(upsp != NULL)) {
168 RB_REMOVE(upsock_t, &upcall_sockets, upsp);
169 /*
170 * The upsp points to stack of NFS mounting thread. Even
171 * though we removed it from the tree, we still don't own it.
172 * Make a copy before releasing the lock. The mounting thread
173 * may timeout the RPC and unroll its stack.
174 */
175 ups = *upsp;
176 }
177 mtx_unlock(&rpctls_lock);
178 if (upsp == NULL) {
179 KRPC_CURVNET_RESTORE();
180 printf("%s: socket lookup failed\n", __func__);
181 return (EPERM);
182 }
183 if ((error = falloc(td, &fp, &fd, 0)) != 0) {
184 /*
185 * The socket will not be acquired by the daemon,
186 * but has been removed from the upcall socket RB.
187 * As such, it needs to be closed here.
188 */
189 soclose(ups.so);
190 KRPC_CURVNET_RESTORE();
191 return (error);
192 }
193 soref(ups.so);
194 if (ups.server) {
195 /*
196 * Once this file descriptor is associated
197 * with the socket, it cannot be closed by
198 * the server side krpc code (svc_vc.c).
199 */
200 sx_xlock(&ups.xp->xp_lock);
201 ups.xp->xp_tls = RPCTLS_FLAGS_HANDSHFAIL;
202 sx_xunlock(&ups.xp->xp_lock);
203 } else {
204 /*
205 * Initialize TLS state so that clnt_vc_destroy() will
206 * not close the socket and will leave that for the
207 * daemon to do.
208 */
209 CLNT_CONTROL(ups.cl, CLSET_TLS, &(int){RPCTLS_INHANDSHAKE});
210 }
211 finit(fp, FREAD | FWRITE, DTYPE_SOCKET, ups.so, &socketops);
212 fdrop(fp, td); /* Drop fp reference. */
213 td->td_retval[0] = fd;
214 KRPC_CURVNET_RESTORE();
215
216 return (error);
217 }
218
219 /* Error handling for both client and server failed RPC upcalls. */
220 static void
rpctls_rpc_failed(struct upsock * ups,struct socket * so)221 rpctls_rpc_failed(struct upsock *ups, struct socket *so)
222 {
223
224 mtx_lock(&rpctls_lock);
225 if (RB_FIND(upsock_t, &upcall_sockets, ups)) {
226 struct upsock *removed __diagused;
227
228 removed = RB_REMOVE(upsock_t, &upcall_sockets, ups);
229 mtx_unlock(&rpctls_lock);
230 MPASS(removed == ups);
231 /*
232 * Since the socket was still in the RB tree when
233 * this function was called, the daemon will not
234 * close it. As such, it needs to be closed here.
235 */
236 soclose(so);
237 } else {
238 /*
239 * The daemon has taken the socket from the tree, but
240 * failed to do the handshake.
241 */
242 mtx_unlock(&rpctls_lock);
243 }
244 }
245
246 /* Do an upcall for a new socket connect using TLS. */
247 enum clnt_stat
rpctls_connect(CLIENT * newclient,char * certname,struct socket * so,uint32_t * reterr)248 rpctls_connect(CLIENT *newclient, char *certname, struct socket *so,
249 uint32_t *reterr)
250 {
251 struct rpctlscd_connect_arg arg;
252 struct rpctlscd_connect_res res;
253 struct rpc_callextra ext;
254 enum clnt_stat stat;
255 struct upsock ups = {
256 .so = so,
257 .cl = newclient,
258 .server = false,
259 };
260
261 /* First, do the AUTH_TLS NULL RPC. */
262 memset(&ext, 0, sizeof(ext));
263 ext.rc_auth = authtls_create();
264 stat = clnt_call_private(newclient, &ext, NULLPROC, (xdrproc_t)xdr_void,
265 NULL, (xdrproc_t)xdr_void, NULL, (struct timeval){ .tv_sec = 30 });
266 AUTH_DESTROY(ext.rc_auth);
267 if (stat == RPC_AUTHERROR)
268 return (stat);
269 if (stat != RPC_SUCCESS)
270 return (RPC_SYSTEMERROR);
271
272 mtx_lock(&rpctls_lock);
273 RB_INSERT(upsock_t, &upcall_sockets, &ups);
274 mtx_unlock(&rpctls_lock);
275
276 /* Temporarily block reception during the handshake upcall. */
277 CLNT_CONTROL(newclient, CLSET_BLOCKRCV, &(int){1});
278
279 /* Do the connect handshake upcall. */
280 if (certname != NULL) {
281 arg.certname.certname_len = strlen(certname);
282 arg.certname.certname_val = certname;
283 } else
284 arg.certname.certname_len = 0;
285 arg.socookie = (uint64_t)so;
286 stat = rpctlscd_connect_2(&arg, &res, rpctls_connect_handle);
287 if (stat == RPC_SUCCESS)
288 *reterr = res.reterr;
289 else
290 rpctls_rpc_failed(&ups, so);
291
292 /* Unblock reception. */
293 CLNT_CONTROL(newclient, CLSET_BLOCKRCV, &(int){0});
294
295 #ifdef INVARIANTS
296 mtx_lock(&rpctls_lock);
297 MPASS((RB_FIND(upsock_t, &upcall_sockets, &ups) == NULL));
298 mtx_unlock(&rpctls_lock);
299 #endif
300
301 return (stat);
302 }
303
304 /* Do an upcall to handle an non-application data record using TLS. */
305 enum clnt_stat
rpctls_cl_handlerecord(void * socookie,uint32_t * reterr)306 rpctls_cl_handlerecord(void *socookie, uint32_t *reterr)
307 {
308 struct rpctlscd_handlerecord_arg arg;
309 struct rpctlscd_handlerecord_res res;
310 enum clnt_stat stat;
311
312 /* Do the handlerecord upcall. */
313 arg.socookie = (uint64_t)socookie;
314 stat = rpctlscd_handlerecord_2(&arg, &res, rpctls_connect_handle);
315 if (stat == RPC_SUCCESS)
316 *reterr = res.reterr;
317 return (stat);
318 }
319
320 enum clnt_stat
rpctls_srv_handlerecord(void * socookie,uint32_t * reterr)321 rpctls_srv_handlerecord(void *socookie, uint32_t *reterr)
322 {
323 struct rpctlssd_handlerecord_arg arg;
324 struct rpctlssd_handlerecord_res res;
325 enum clnt_stat stat;
326
327 /* Do the handlerecord upcall. */
328 arg.socookie = (uint64_t)socookie;
329 stat = rpctlssd_handlerecord_2(&arg, &res, rpctls_server_handle);
330 if (stat == RPC_SUCCESS)
331 *reterr = res.reterr;
332 return (stat);
333 }
334
335 /* Do an upcall to shut down a socket using TLS. */
336 enum clnt_stat
rpctls_cl_disconnect(void * socookie,uint32_t * reterr)337 rpctls_cl_disconnect(void *socookie, uint32_t *reterr)
338 {
339 struct rpctlscd_disconnect_arg arg;
340 struct rpctlscd_disconnect_res res;
341 enum clnt_stat stat;
342
343 /* Do the disconnect upcall. */
344 arg.socookie = (uint64_t)socookie;
345 stat = rpctlscd_disconnect_2(&arg, &res, rpctls_connect_handle);
346 if (stat == RPC_SUCCESS)
347 *reterr = res.reterr;
348 return (stat);
349 }
350
351 enum clnt_stat
rpctls_srv_disconnect(void * socookie,uint32_t * reterr)352 rpctls_srv_disconnect(void *socookie, uint32_t *reterr)
353 {
354 struct rpctlssd_disconnect_arg arg;
355 struct rpctlssd_disconnect_res res;
356 enum clnt_stat stat;
357
358 /* Do the disconnect upcall. */
359 arg.socookie = (uint64_t)socookie;
360 stat = rpctlssd_disconnect_2(&arg, &res, rpctls_server_handle);
361 if (stat == RPC_SUCCESS)
362 *reterr = res.reterr;
363 return (stat);
364 }
365
366 /* Do an upcall for a new server socket using TLS. */
367 static enum clnt_stat
rpctls_server(SVCXPRT * xprt,uint32_t * flags,uid_t * uid,int * ngrps,gid_t ** gids)368 rpctls_server(SVCXPRT *xprt, uint32_t *flags, uid_t *uid, int *ngrps,
369 gid_t **gids)
370 {
371 enum clnt_stat stat;
372 struct upsock ups = {
373 .so = xprt->xp_socket,
374 .xp = xprt,
375 .server = true,
376 };
377 struct rpctlssd_connect_arg arg;
378 struct rpctlssd_connect_res res;
379 gid_t *gidp;
380 uint32_t *gidv;
381 int i;
382
383 mtx_lock(&rpctls_lock);
384 RB_INSERT(upsock_t, &upcall_sockets, &ups);
385 mtx_unlock(&rpctls_lock);
386
387 /* Do the server upcall. */
388 res.gid.gid_val = NULL;
389 arg.socookie = (uint64_t)xprt->xp_socket;
390 stat = rpctlssd_connect_2(&arg, &res, rpctls_server_handle);
391 if (stat == RPC_SUCCESS) {
392 *flags = res.flags;
393 if ((*flags & (RPCTLS_FLAGS_CERTUSER |
394 RPCTLS_FLAGS_DISABLED)) == RPCTLS_FLAGS_CERTUSER) {
395 *ngrps = res.gid.gid_len;
396 *uid = res.uid;
397 *gids = gidp = mem_alloc(*ngrps * sizeof(gid_t));
398 gidv = res.gid.gid_val;
399 for (i = 0; i < *ngrps; i++)
400 *gidp++ = *gidv++;
401 }
402 } else
403 rpctls_rpc_failed(&ups, xprt->xp_socket);
404
405 mem_free(res.gid.gid_val, 0);
406
407 #ifdef INVARIANTS
408 mtx_lock(&rpctls_lock);
409 MPASS((RB_FIND(upsock_t, &upcall_sockets, &ups) == NULL));
410 mtx_unlock(&rpctls_lock);
411 #endif
412
413 return (stat);
414 }
415
416 /*
417 * Handle the NULL RPC with authentication flavor of AUTH_TLS.
418 * This is a STARTTLS command, so do the upcall to the rpctlssd daemon,
419 * which will do the TLS handshake.
420 */
421 enum auth_stat
_svcauth_rpcsec_tls(struct svc_req * rqst,struct rpc_msg * msg)422 _svcauth_rpcsec_tls(struct svc_req *rqst, struct rpc_msg *msg)
423
424 {
425 bool_t call_stat;
426 enum clnt_stat stat;
427 SVCXPRT *xprt;
428 uint32_t flags;
429 int ngrps;
430 uid_t uid;
431 gid_t *gidp;
432 #ifdef KERN_TLS
433 u_int maxlen;
434 #endif
435
436 KRPC_CURVNET_SET_QUIET(KRPC_TD_TO_VNET(curthread));
437 KRPC_VNET(svc_vc_tls_handshake_failed)++;
438 /* Initialize reply. */
439 rqst->rq_verf = rpctls_null_verf;
440
441 /* Check client credentials. */
442 if (rqst->rq_cred.oa_length != 0 ||
443 msg->rm_call.cb_verf.oa_length != 0 ||
444 msg->rm_call.cb_verf.oa_flavor != AUTH_NULL) {
445 KRPC_CURVNET_RESTORE();
446 return (AUTH_BADCRED);
447 }
448
449 if (rqst->rq_proc != NULLPROC) {
450 KRPC_CURVNET_RESTORE();
451 return (AUTH_REJECTEDCRED);
452 }
453
454 call_stat = FALSE;
455 #ifdef KERN_TLS
456 if (rpctls_getinfo(&maxlen, false, true))
457 call_stat = TRUE;
458 #endif
459 if (!call_stat) {
460 KRPC_CURVNET_RESTORE();
461 return (AUTH_REJECTEDCRED);
462 }
463
464 /*
465 * Disable reception for the krpc so that the TLS handshake can
466 * be done on the socket in the rpctlssd daemon.
467 */
468 xprt = rqst->rq_xprt;
469 sx_xlock(&xprt->xp_lock);
470 xprt->xp_dontrcv = TRUE;
471 sx_xunlock(&xprt->xp_lock);
472
473 /*
474 * Send the reply to the NULL RPC with AUTH_TLS, which is the
475 * STARTTLS command for Sun RPC.
476 */
477 call_stat = svc_sendreply(rqst, (xdrproc_t)xdr_void, NULL);
478 if (!call_stat) {
479 sx_xlock(&xprt->xp_lock);
480 xprt->xp_dontrcv = FALSE;
481 sx_xunlock(&xprt->xp_lock);
482 xprt_active(xprt); /* Harmless if already active. */
483 KRPC_CURVNET_RESTORE();
484 return (AUTH_REJECTEDCRED);
485 }
486
487 /* Do an upcall to do the TLS handshake. */
488 stat = rpctls_server(xprt, &flags, &uid, &ngrps, &gidp);
489
490 /* Re-enable reception on the socket within the krpc. */
491 sx_xlock(&xprt->xp_lock);
492 xprt->xp_dontrcv = FALSE;
493 if (stat == RPC_SUCCESS) {
494 xprt->xp_tls = flags;
495 if ((flags & (RPCTLS_FLAGS_CERTUSER |
496 RPCTLS_FLAGS_DISABLED)) == RPCTLS_FLAGS_CERTUSER) {
497 xprt->xp_ngrps = ngrps;
498 xprt->xp_uid = uid;
499 xprt->xp_gidp = gidp;
500 }
501 KRPC_VNET(svc_vc_tls_handshake_failed)--;
502 KRPC_VNET(svc_vc_tls_handshake_success)++;
503 }
504 sx_xunlock(&xprt->xp_lock);
505 xprt_active(xprt); /* Harmless if already active. */
506 KRPC_CURVNET_RESTORE();
507
508 return (RPCSEC_GSS_NODISPATCH);
509 }
510
511 /*
512 * Get kern.ipc.tls.enable and kern.ipc.tls.maxlen.
513 */
514 bool
rpctls_getinfo(u_int * maxlenp,bool rpctlscd_run,bool rpctlssd_run)515 rpctls_getinfo(u_int *maxlenp, bool rpctlscd_run, bool rpctlssd_run)
516 {
517 u_int maxlen;
518 bool enable;
519 int error;
520 size_t siz;
521
522 if (!mb_use_ext_pgs)
523 return (false);
524 siz = sizeof(enable);
525 error = kernel_sysctlbyname(curthread, "kern.ipc.tls.enable",
526 &enable, &siz, NULL, 0, NULL, 0);
527 if (error != 0)
528 return (false);
529 siz = sizeof(maxlen);
530 error = kernel_sysctlbyname(curthread, "kern.ipc.tls.maxlen",
531 &maxlen, &siz, NULL, 0, NULL, 0);
532 if (error != 0)
533 return (false);
534 *maxlenp = maxlen;
535 return (enable);
536 }
537