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 KRPC_CURVNET_RESTORE();
185 return (error);
186 }
187 soref(ups.so);
188 if (ups.server) {
189 /*
190 * Once this file descriptor is associated
191 * with the socket, it cannot be closed by
192 * the server side krpc code (svc_vc.c).
193 */
194 sx_xlock(&ups.xp->xp_lock);
195 ups.xp->xp_tls = RPCTLS_FLAGS_HANDSHFAIL;
196 sx_xunlock(&ups.xp->xp_lock);
197 } else {
198 /*
199 * Initialize TLS state so that clnt_vc_destroy() will
200 * not close the socket and will leave that for the
201 * daemon to do.
202 */
203 CLNT_CONTROL(ups.cl, CLSET_TLS, &(int){RPCTLS_INHANDSHAKE});
204 }
205 finit(fp, FREAD | FWRITE, DTYPE_SOCKET, ups.so, &socketops);
206 fdrop(fp, td); /* Drop fp reference. */
207 td->td_retval[0] = fd;
208 KRPC_CURVNET_RESTORE();
209
210 return (error);
211 }
212
213 /* Error handling for both client and server failed RPC upcalls. */
214 static void
rpctls_rpc_failed(struct upsock * ups,struct socket * so)215 rpctls_rpc_failed(struct upsock *ups, struct socket *so)
216 {
217
218 mtx_lock(&rpctls_lock);
219 if (RB_FIND(upsock_t, &upcall_sockets, ups)) {
220 struct upsock *removed __diagused;
221
222 removed = RB_REMOVE(upsock_t, &upcall_sockets, ups);
223 mtx_unlock(&rpctls_lock);
224 MPASS(removed == ups);
225 /*
226 * Do a shutdown on the socket, since the daemon is
227 * probably stuck in SSL_accept() trying to read the
228 * socket. Do not soclose() the socket, since the
229 * daemon will close() the socket after SSL_accept()
230 * returns an error.
231 */
232 soshutdown(so, SHUT_RD);
233 } else {
234 /*
235 * The daemon has taken the socket from the tree, but
236 * failed to do the handshake.
237 */
238 mtx_unlock(&rpctls_lock);
239 }
240 }
241
242 /* Do an upcall for a new socket connect using TLS. */
243 enum clnt_stat
rpctls_connect(CLIENT * newclient,char * certname,struct socket * so,uint32_t * reterr)244 rpctls_connect(CLIENT *newclient, char *certname, struct socket *so,
245 uint32_t *reterr)
246 {
247 struct rpctlscd_connect_arg arg;
248 struct rpctlscd_connect_res res;
249 struct rpc_callextra ext;
250 enum clnt_stat stat;
251 struct upsock ups = {
252 .so = so,
253 .cl = newclient,
254 .server = false,
255 };
256
257 /* First, do the AUTH_TLS NULL RPC. */
258 memset(&ext, 0, sizeof(ext));
259 ext.rc_auth = authtls_create();
260 stat = clnt_call_private(newclient, &ext, NULLPROC, (xdrproc_t)xdr_void,
261 NULL, (xdrproc_t)xdr_void, NULL, (struct timeval){ .tv_sec = 30 });
262 AUTH_DESTROY(ext.rc_auth);
263 if (stat == RPC_AUTHERROR)
264 return (stat);
265 if (stat != RPC_SUCCESS)
266 return (RPC_SYSTEMERROR);
267
268 mtx_lock(&rpctls_lock);
269 RB_INSERT(upsock_t, &upcall_sockets, &ups);
270 mtx_unlock(&rpctls_lock);
271
272 /* Temporarily block reception during the handshake upcall. */
273 CLNT_CONTROL(newclient, CLSET_BLOCKRCV, &(int){1});
274
275 /* Do the connect handshake upcall. */
276 if (certname != NULL) {
277 arg.certname.certname_len = strlen(certname);
278 arg.certname.certname_val = certname;
279 } else
280 arg.certname.certname_len = 0;
281 arg.socookie = (uint64_t)so;
282 stat = rpctlscd_connect_2(&arg, &res, rpctls_connect_handle);
283 if (stat == RPC_SUCCESS)
284 *reterr = res.reterr;
285 else
286 rpctls_rpc_failed(&ups, so);
287
288 /* Unblock reception. */
289 CLNT_CONTROL(newclient, CLSET_BLOCKRCV, &(int){0});
290
291 #ifdef INVARIANTS
292 mtx_lock(&rpctls_lock);
293 MPASS((RB_FIND(upsock_t, &upcall_sockets, &ups) == NULL));
294 mtx_unlock(&rpctls_lock);
295 #endif
296
297 return (stat);
298 }
299
300 /* Do an upcall to handle an non-application data record using TLS. */
301 enum clnt_stat
rpctls_cl_handlerecord(void * socookie,uint32_t * reterr)302 rpctls_cl_handlerecord(void *socookie, uint32_t *reterr)
303 {
304 struct rpctlscd_handlerecord_arg arg;
305 struct rpctlscd_handlerecord_res res;
306 enum clnt_stat stat;
307
308 /* Do the handlerecord upcall. */
309 arg.socookie = (uint64_t)socookie;
310 stat = rpctlscd_handlerecord_2(&arg, &res, rpctls_connect_handle);
311 if (stat == RPC_SUCCESS)
312 *reterr = res.reterr;
313 return (stat);
314 }
315
316 enum clnt_stat
rpctls_srv_handlerecord(void * socookie,uint32_t * reterr)317 rpctls_srv_handlerecord(void *socookie, uint32_t *reterr)
318 {
319 struct rpctlssd_handlerecord_arg arg;
320 struct rpctlssd_handlerecord_res res;
321 enum clnt_stat stat;
322
323 /* Do the handlerecord upcall. */
324 arg.socookie = (uint64_t)socookie;
325 stat = rpctlssd_handlerecord_2(&arg, &res, rpctls_server_handle);
326 if (stat == RPC_SUCCESS)
327 *reterr = res.reterr;
328 return (stat);
329 }
330
331 /* Do an upcall to shut down a socket using TLS. */
332 enum clnt_stat
rpctls_cl_disconnect(void * socookie,uint32_t * reterr)333 rpctls_cl_disconnect(void *socookie, uint32_t *reterr)
334 {
335 struct rpctlscd_disconnect_arg arg;
336 struct rpctlscd_disconnect_res res;
337 enum clnt_stat stat;
338
339 /* Do the disconnect upcall. */
340 arg.socookie = (uint64_t)socookie;
341 stat = rpctlscd_disconnect_2(&arg, &res, rpctls_connect_handle);
342 if (stat == RPC_SUCCESS)
343 *reterr = res.reterr;
344 return (stat);
345 }
346
347 enum clnt_stat
rpctls_srv_disconnect(void * socookie,uint32_t * reterr)348 rpctls_srv_disconnect(void *socookie, uint32_t *reterr)
349 {
350 struct rpctlssd_disconnect_arg arg;
351 struct rpctlssd_disconnect_res res;
352 enum clnt_stat stat;
353
354 /* Do the disconnect upcall. */
355 arg.socookie = (uint64_t)socookie;
356 stat = rpctlssd_disconnect_2(&arg, &res, rpctls_server_handle);
357 if (stat == RPC_SUCCESS)
358 *reterr = res.reterr;
359 return (stat);
360 }
361
362 /* Do an upcall for a new server socket using TLS. */
363 static enum clnt_stat
rpctls_server(SVCXPRT * xprt,uint32_t * flags,uid_t * uid,int * ngrps,gid_t ** gids)364 rpctls_server(SVCXPRT *xprt, uint32_t *flags, uid_t *uid, int *ngrps,
365 gid_t **gids)
366 {
367 enum clnt_stat stat;
368 struct upsock ups = {
369 .so = xprt->xp_socket,
370 .xp = xprt,
371 .server = true,
372 };
373 struct rpctlssd_connect_arg arg;
374 struct rpctlssd_connect_res res;
375 gid_t *gidp;
376 uint32_t *gidv;
377 int i;
378
379 mtx_lock(&rpctls_lock);
380 RB_INSERT(upsock_t, &upcall_sockets, &ups);
381 mtx_unlock(&rpctls_lock);
382
383 /* Do the server upcall. */
384 res.gid.gid_val = NULL;
385 arg.socookie = (uint64_t)xprt->xp_socket;
386 stat = rpctlssd_connect_2(&arg, &res, rpctls_server_handle);
387 if (stat == RPC_SUCCESS) {
388 *flags = res.flags;
389 if ((*flags & (RPCTLS_FLAGS_CERTUSER |
390 RPCTLS_FLAGS_DISABLED)) == RPCTLS_FLAGS_CERTUSER) {
391 *ngrps = res.gid.gid_len;
392 *uid = res.uid;
393 *gids = gidp = mem_alloc(*ngrps * sizeof(gid_t));
394 gidv = res.gid.gid_val;
395 for (i = 0; i < *ngrps; i++)
396 *gidp++ = *gidv++;
397 }
398 } else
399 rpctls_rpc_failed(&ups, xprt->xp_socket);
400
401 mem_free(res.gid.gid_val, 0);
402
403 #ifdef INVARIANTS
404 mtx_lock(&rpctls_lock);
405 MPASS((RB_FIND(upsock_t, &upcall_sockets, &ups) == NULL));
406 mtx_unlock(&rpctls_lock);
407 #endif
408
409 return (stat);
410 }
411
412 /*
413 * Handle the NULL RPC with authentication flavor of AUTH_TLS.
414 * This is a STARTTLS command, so do the upcall to the rpctlssd daemon,
415 * which will do the TLS handshake.
416 */
417 enum auth_stat
_svcauth_rpcsec_tls(struct svc_req * rqst,struct rpc_msg * msg)418 _svcauth_rpcsec_tls(struct svc_req *rqst, struct rpc_msg *msg)
419
420 {
421 bool_t call_stat;
422 enum clnt_stat stat;
423 SVCXPRT *xprt;
424 uint32_t flags;
425 int ngrps;
426 uid_t uid;
427 gid_t *gidp;
428 #ifdef KERN_TLS
429 u_int maxlen;
430 #endif
431
432 KRPC_CURVNET_SET_QUIET(KRPC_TD_TO_VNET(curthread));
433 KRPC_VNET(svc_vc_tls_handshake_failed)++;
434 /* Initialize reply. */
435 rqst->rq_verf = rpctls_null_verf;
436
437 /* Check client credentials. */
438 if (rqst->rq_cred.oa_length != 0 ||
439 msg->rm_call.cb_verf.oa_length != 0 ||
440 msg->rm_call.cb_verf.oa_flavor != AUTH_NULL) {
441 KRPC_CURVNET_RESTORE();
442 return (AUTH_BADCRED);
443 }
444
445 if (rqst->rq_proc != NULLPROC) {
446 KRPC_CURVNET_RESTORE();
447 return (AUTH_REJECTEDCRED);
448 }
449
450 call_stat = FALSE;
451 #ifdef KERN_TLS
452 if (rpctls_getinfo(&maxlen, false, true))
453 call_stat = TRUE;
454 #endif
455 if (!call_stat) {
456 KRPC_CURVNET_RESTORE();
457 return (AUTH_REJECTEDCRED);
458 }
459
460 /*
461 * Disable reception for the krpc so that the TLS handshake can
462 * be done on the socket in the rpctlssd daemon.
463 */
464 xprt = rqst->rq_xprt;
465 sx_xlock(&xprt->xp_lock);
466 xprt->xp_dontrcv = TRUE;
467 sx_xunlock(&xprt->xp_lock);
468
469 /*
470 * Send the reply to the NULL RPC with AUTH_TLS, which is the
471 * STARTTLS command for Sun RPC.
472 */
473 call_stat = svc_sendreply(rqst, (xdrproc_t)xdr_void, NULL);
474 if (!call_stat) {
475 sx_xlock(&xprt->xp_lock);
476 xprt->xp_dontrcv = FALSE;
477 sx_xunlock(&xprt->xp_lock);
478 xprt_active(xprt); /* Harmless if already active. */
479 KRPC_CURVNET_RESTORE();
480 return (AUTH_REJECTEDCRED);
481 }
482
483 /* Do an upcall to do the TLS handshake. */
484 stat = rpctls_server(xprt, &flags, &uid, &ngrps, &gidp);
485
486 /* Re-enable reception on the socket within the krpc. */
487 sx_xlock(&xprt->xp_lock);
488 xprt->xp_dontrcv = FALSE;
489 if (stat == RPC_SUCCESS) {
490 xprt->xp_tls = flags;
491 if ((flags & (RPCTLS_FLAGS_CERTUSER |
492 RPCTLS_FLAGS_DISABLED)) == RPCTLS_FLAGS_CERTUSER) {
493 xprt->xp_ngrps = ngrps;
494 xprt->xp_uid = uid;
495 xprt->xp_gidp = gidp;
496 }
497 KRPC_VNET(svc_vc_tls_handshake_failed)--;
498 KRPC_VNET(svc_vc_tls_handshake_success)++;
499 }
500 sx_xunlock(&xprt->xp_lock);
501 xprt_active(xprt); /* Harmless if already active. */
502 KRPC_CURVNET_RESTORE();
503
504 return (RPCSEC_GSS_NODISPATCH);
505 }
506
507 /*
508 * Get kern.ipc.tls.enable and kern.ipc.tls.maxlen.
509 */
510 bool
rpctls_getinfo(u_int * maxlenp,bool rpctlscd_run,bool rpctlssd_run)511 rpctls_getinfo(u_int *maxlenp, bool rpctlscd_run, bool rpctlssd_run)
512 {
513 u_int maxlen;
514 bool enable;
515 int error;
516 size_t siz;
517
518 if (!mb_use_ext_pgs)
519 return (false);
520 siz = sizeof(enable);
521 error = kernel_sysctlbyname(curthread, "kern.ipc.tls.enable",
522 &enable, &siz, NULL, 0, NULL, 0);
523 if (error != 0)
524 return (false);
525 siz = sizeof(maxlen);
526 error = kernel_sysctlbyname(curthread, "kern.ipc.tls.maxlen",
527 &maxlen, &siz, NULL, 0, NULL, 0);
528 if (error != 0)
529 return (false);
530 *maxlenp = maxlen;
531 return (enable);
532 }
533