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 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 * 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 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 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 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 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 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 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 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 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 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 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 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