sunrpc/svc_unix.c

   1 /*
   2  * svc_unix.c, Server side for TCP/IP based RPC.
   3  *
   4  * Copyright (C) 2012-2017 Free Software Foundation, Inc.
   5  * This file is part of the GNU C Library.
   6  *
   7  * The GNU C Library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * The GNU C Library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with the GNU C Library; if not, see
  19  * <http://www.gnu.org/licenses/>.
  20  *
  21  * Copyright (c) 2010, Oracle America, Inc.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions are
  25  * met:
  26  *
  27  *     * Redistributions of source code must retain the above copyright
  28  *       notice, this list of conditions and the following disclaimer.
  29  *     * Redistributions in binary form must reproduce the above
  30  *       copyright notice, this list of conditions and the following
  31  *       disclaimer in the documentation and/or other materials
  32  *       provided with the distribution.
  33  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  34  *       contributors may be used to endorse or promote products derived
  35  *       from this software without specific prior written permission.
  36  *
  37  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  38  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  39  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  40  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  41  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  42  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  43  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  44  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  45  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  46  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  47  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  48  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  49  *
  50  * Actually implements two flavors of transporter -
  51  * a unix rendezvouser (a listener and connection establisher)
  52  * and a record/unix stream.
  53  */
  54
  55 #include <stdio.h>
  56 #include <unistd.h>
  57 #include <string.h>
  58 #include <rpc/rpc.h>
  59 #include <rpc/svc.h>
  60 #include <sys/socket.h>
  61 #include <sys/uio.h>
  62 #include <sys/poll.h>
  63 #include <errno.h>
  64 #include <stdlib.h>
  65 #include <libintl.h>
  66 #include <wchar.h>
  67 #include <shlib-compat.h>
  68
  69 /*
  70  * Ops vector for AF_UNIX based rpc service handle
  71  */
  72 static bool_t svcunix_recv (SVCXPRT *, struct rpc_msg *);
  73 static enum xprt_stat svcunix_stat (SVCXPRT *);
  74 static bool_t svcunix_getargs (SVCXPRT *, xdrproc_t, caddr_t);
  75 static bool_t svcunix_reply (SVCXPRT *, struct rpc_msg *);
  76 static bool_t svcunix_freeargs (SVCXPRT *, xdrproc_t, caddr_t);
  77 static void svcunix_destroy (SVCXPRT *);
  78
  79 static const struct xp_ops svcunix_op =
  80 {
  81   svcunix_recv,
  82   svcunix_stat,
  83   svcunix_getargs,
  84   svcunix_reply,
  85   svcunix_freeargs,
  86   svcunix_destroy
  87 };
  88
  89 /*
  90  * Ops vector for AF_UNIX rendezvous handler
  91  */
  92 static bool_t rendezvous_request (SVCXPRT *, struct rpc_msg *);
  93 static enum xprt_stat rendezvous_stat (SVCXPRT *);
  94 static void svcunix_rendezvous_abort (void) __attribute__ ((__noreturn__));
  95
  96 /* This function makes sure abort() relocation goes through PLT
  97    and thus can be lazy bound.  */
  98 static void
  99 svcunix_rendezvous_abort (void)
 100 {
 101   abort ();
 102 };
 103
 104 static const struct xp_ops svcunix_rendezvous_op =
 105 {
 106   rendezvous_request,
 107   rendezvous_stat,
 108   (bool_t (*) (SVCXPRT *, xdrproc_t, caddr_t)) svcunix_rendezvous_abort,
 109   (bool_t (*) (SVCXPRT *, struct rpc_msg *)) svcunix_rendezvous_abort,
 110   (bool_t (*) (SVCXPRT *, xdrproc_t, caddr_t)) svcunix_rendezvous_abort,
 111   svcunix_destroy
 112 };
 113
 114 static int readunix (char*, char *, int);
 115 static int writeunix (char *, char *, int);
 116 static SVCXPRT *makefd_xprt (int, u_int, u_int);
 117
 118 struct unix_rendezvous {        /* kept in xprt->xp_p1 */
 119   u_int sendsize;
 120   u_int recvsize;
 121 };
 122
 123 struct unix_conn {              /* kept in xprt->xp_p1 */
 124   enum xprt_stat strm_stat;
 125   u_long x_id;
 126   XDR xdrs;
 127   char verf_body[MAX_AUTH_BYTES];
 128 };
 129
 130 /*
 131  * Usage:
 132  *      xprt = svcunix_create(sock, send_buf_size, recv_buf_size);
 133  *
 134  * Creates, registers, and returns a (rpc) unix based transporter.
 135  * Once *xprt is initialized, it is registered as a transporter
 136  * see (svc.h, xprt_register).  This routine returns
 137  * a NULL if a problem occurred.
 138  *
 139  * If sock<0 then a socket is created, else sock is used.
 140  * If the socket, sock is not bound to a port then svcunix_create
 141  * binds it to an arbitrary port.  The routine then starts a unix
 142  * listener on the socket's associated port.  In any (successful) case,
 143  * xprt->xp_sock is the registered socket number and xprt->xp_port is the
 144  * associated port number.
 145  *
 146  * Since unix streams do buffered io similar to stdio, the caller can specify
 147  * how big the send and receive buffers are via the second and third parms;
 148  * 0 => use the system default.
 149  */
 150 SVCXPRT *
 151 svcunix_create (int sock, u_int sendsize, u_int recvsize, char *path)
 152 {
 153   bool_t madesock = FALSE;
 154   SVCXPRT *xprt;
 155   struct unix_rendezvous *r;
 156   struct sockaddr_un addr;
 157   socklen_t len = sizeof (struct sockaddr_in);
 158
 159   if (sock == RPC_ANYSOCK)
 160     {
 161       if ((sock = __socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 162         {
 163           perror (_("svc_unix.c - AF_UNIX socket creation problem"));
 164           return (SVCXPRT *) NULL;
 165         }
 166       madesock = TRUE;
 167     }
 168   memset (&addr, '\0', sizeof (addr));
 169   addr.sun_family = AF_UNIX;
 170   len = strlen (path) + 1;
 171   memcpy (addr.sun_path, path, len);
 172   len += sizeof (addr.sun_family);
 173
 174   __bind (sock, (struct sockaddr *) &addr, len);
 175
 176   if (__getsockname (sock, (struct sockaddr *) &addr, &len) != 0
 177       || __listen (sock, SOMAXCONN) != 0)
 178     {
 179       perror (_("svc_unix.c - cannot getsockname or listen"));
 180       if (madesock)
 181         __close (sock);
 182       return (SVCXPRT *) NULL;
 183     }
 184
 185   r = (struct unix_rendezvous *) mem_alloc (sizeof (*r));
 186   xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));
 187   if (r == NULL || xprt == NULL)
 188     {
 189       __fxprintf (NULL, "%s: %s", __func__, _("out of memory\n"));
 190       mem_free (r, sizeof (*r));
 191       mem_free (xprt, sizeof (SVCXPRT));
 192       return NULL;
 193     }
 194   r->sendsize = sendsize;
 195   r->recvsize = recvsize;
 196   xprt->xp_p2 = NULL;
 197   xprt->xp_p1 = (caddr_t) r;
 198   xprt->xp_verf = _null_auth;
 199   xprt->xp_ops = &svcunix_rendezvous_op;
 200   xprt->xp_port = -1;
 201   xprt->xp_sock = sock;
 202   xprt_register (xprt);
 203   return xprt;
 204 }
 205 libc_hidden_nolink_sunrpc (svcunix_create, GLIBC_2_1)
 206
 207 /*
 208  * Like svunix_create(), except the routine takes any *open* UNIX file
 209  * descriptor as its first input.
 210  */
 211 SVCXPRT *
 212 svcunixfd_create (int fd, u_int sendsize, u_int recvsize)
 213 {
 214   return makefd_xprt (fd, sendsize, recvsize);
 215 }
 216 libc_hidden_nolink_sunrpc (svcunixfd_create, GLIBC_2_1)
 217
 218 static SVCXPRT *
 219 makefd_xprt (int fd, u_int sendsize, u_int recvsize)
 220 {
 221   SVCXPRT *xprt;
 222   struct unix_conn *cd;
 223
 224   xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));
 225   cd = (struct unix_conn *) mem_alloc (sizeof (struct unix_conn));
 226   if (xprt == (SVCXPRT *) NULL || cd == (struct unix_conn *) NULL)
 227     {
 228       (void) __fxprintf (NULL, "%s: %s", "svc_unix: makefd_xprt",
 229                          _("out of memory\n"));
 230       mem_free (xprt, sizeof (SVCXPRT));
 231       mem_free (cd, sizeof (struct unix_conn));
 232       return NULL;
 233     }
 234   cd->strm_stat = XPRT_IDLE;
 235   xdrrec_create (&(cd->xdrs), sendsize, recvsize,
 236                  (caddr_t) xprt, readunix, writeunix);
 237   xprt->xp_p2 = NULL;
 238   xprt->xp_p1 = (caddr_t) cd;
 239   xprt->xp_verf.oa_base = cd->verf_body;
 240   xprt->xp_addrlen = 0;
 241   xprt->xp_ops = &svcunix_op;   /* truly deals with calls */
 242   xprt->xp_port = 0;            /* this is a connection, not a rendezvouser */
 243   xprt->xp_sock = fd;
 244   xprt_register (xprt);
 245   return xprt;
 246 }
 247
 248 static bool_t
 249 rendezvous_request (SVCXPRT *xprt, struct rpc_msg *errmsg)
 250 {
 251   int sock;
 252   struct unix_rendezvous *r;
 253   struct sockaddr_un addr;
 254   struct sockaddr_in in_addr;
 255   socklen_t len;
 256
 257   r = (struct unix_rendezvous *) xprt->xp_p1;
 258 again:
 259   len = sizeof (struct sockaddr_un);
 260   if ((sock = accept (xprt->xp_sock, (struct sockaddr *) &addr, &len)) < 0)
 261     {
 262       if (errno == EINTR)
 263         goto again;
 264       __svc_accept_failed ();
 265       return FALSE;
 266     }
 267   /*
 268    * make a new transporter (re-uses xprt)
 269    */
 270   memset (&in_addr, '\0', sizeof (in_addr));
 271   in_addr.sin_family = AF_UNIX;
 272   xprt = makefd_xprt (sock, r->sendsize, r->recvsize);
 273   memcpy (&xprt->xp_raddr, &in_addr, sizeof (in_addr));
 274   xprt->xp_addrlen = len;
 275   return FALSE;         /* there is never an rpc msg to be processed */
 276 }
 277
 278 static enum xprt_stat
 279 rendezvous_stat (SVCXPRT *xprt)
 280 {
 281   return XPRT_IDLE;
 282 }
 283
 284 static void
 285 svcunix_destroy (SVCXPRT *xprt)
 286 {
 287   struct unix_conn *cd = (struct unix_conn *) xprt->xp_p1;
 288
 289   xprt_unregister (xprt);
 290   __close (xprt->xp_sock);
 291   if (xprt->xp_port != 0)
 292     {
 293       /* a rendezvouser socket */
 294       xprt->xp_port = 0;
 295     }
 296   else
 297     {
 298       /* an actual connection socket */
 299       XDR_DESTROY (&(cd->xdrs));
 300     }
 301   mem_free ((caddr_t) cd, sizeof (struct unix_conn));
 302   mem_free ((caddr_t) xprt, sizeof (SVCXPRT));
 303 }
 304
 305 #ifdef SCM_CREDENTIALS
 306 struct cmessage {
 307   struct cmsghdr cmsg;
 308   struct ucred cmcred;
 309   /* hack to make sure we have enough memory */
 310   char dummy[(CMSG_ALIGN (sizeof (struct ucred)) - sizeof (struct ucred) + sizeof (long))];
 311 };
 312
 313 /* XXX This is not thread safe, but since the main functions in svc.c
 314    and the rpcgen generated *_svc functions for the daemon are also not
 315    thread safe and uses static global variables, it doesn't matter. */
 316 static struct cmessage cm;
 317 #endif
 318
 319 static int
 320 __msgread (int sock, void *data, size_t cnt)
 321 {
 322   struct iovec iov;
 323   struct msghdr msg;
 324   int len;
 325
 326   iov.iov_base = data;
 327   iov.iov_len = cnt;
 328
 329   msg.msg_iov = &iov;
 330   msg.msg_iovlen = 1;
 331   msg.msg_name = NULL;
 332   msg.msg_namelen = 0;
 333 #ifdef SCM_CREDENTIALS
 334   msg.msg_control = (caddr_t) &cm;
 335   msg.msg_controllen = sizeof (struct cmessage);
 336 #endif
 337   msg.msg_flags = 0;
 338
 339 #ifdef SO_PASSCRED
 340   {
 341     int on = 1;
 342     if (__setsockopt (sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof (on)))
 343       return -1;
 344   }
 345 #endif
 346
 347  restart:
 348   len = __recvmsg (sock, &msg, 0);
 349   if (len >= 0)
 350     {
 351       if (msg.msg_flags & MSG_CTRUNC || len == 0)
 352         return 0;
 353       else
 354         return len;
 355     }
 356   if (errno == EINTR)
 357     goto restart;
 358   return -1;
 359 }
 360
 361 static int
 362 __msgwrite (int sock, void *data, size_t cnt)
 363 {
 364 #ifndef SCM_CREDENTIALS
 365   /* We cannot implement this reliably.  */
 366   __set_errno (ENOSYS);
 367   return -1;
 368 #else
 369   struct iovec iov;
 370   struct msghdr msg;
 371   struct cmsghdr *cmsg = &cm.cmsg;
 372   struct ucred cred;
 373   int len;
 374
 375   /* XXX I'm not sure, if gete?id() is always correct, or if we should use
 376      get?id(). But since keyserv needs geteuid(), we have no other chance.
 377      It would be much better, if the kernel could pass both to the server. */
 378   cred.pid = __getpid ();
 379   cred.uid = __geteuid ();
 380   cred.gid = __getegid ();
 381
 382   memcpy (CMSG_DATA(cmsg), &cred, sizeof (struct ucred));
 383   cmsg->cmsg_level = SOL_SOCKET;
 384   cmsg->cmsg_type = SCM_CREDENTIALS;
 385   cmsg->cmsg_len = sizeof(*cmsg) + sizeof(struct ucred);
 386
 387   iov.iov_base = data;
 388   iov.iov_len = cnt;
 389
 390   msg.msg_iov = &iov;
 391   msg.msg_iovlen = 1;
 392   msg.msg_name = NULL;
 393   msg.msg_namelen = 0;
 394   msg.msg_control = cmsg;
 395   msg.msg_controllen = CMSG_ALIGN(cmsg->cmsg_len);
 396   msg.msg_flags = 0;
 397
 398  restart:
 399   len = __sendmsg (sock, &msg, 0);
 400   if (len >= 0)
 401     return len;
 402   if (errno == EINTR)
 403     goto restart;
 404   return -1;
 405
 406 #endif
 407 }
 408
 409 /*
 410  * reads data from the unix connection.
 411  * any error is fatal and the connection is closed.
 412  * (And a read of zero bytes is a half closed stream => error.)
 413  */
 414 static int
 415 readunix (char *xprtptr, char *buf, int len)
 416 {
 417   SVCXPRT *xprt = (SVCXPRT *) xprtptr;
 418   int sock = xprt->xp_sock;
 419   int milliseconds = 35 * 1000;
 420   struct pollfd pollfd;
 421
 422   do
 423     {
 424       pollfd.fd = sock;
 425       pollfd.events = POLLIN;
 426       switch (__poll (&pollfd, 1, milliseconds))
 427         {
 428         case -1:
 429           if (errno == EINTR)
 430             continue;
 431           /*FALLTHROUGH*/
 432         case 0:
 433           goto fatal_err;
 434         default:
 435           if ((pollfd.revents & POLLERR) || (pollfd.revents & POLLHUP)
 436               || (pollfd.revents & POLLNVAL))
 437             goto fatal_err;
 438           break;
 439         }
 440     }
 441   while ((pollfd.revents & POLLIN) == 0);
 442
 443   if ((len = __msgread (sock, buf, len)) > 0)
 444     return len;
 445
 446  fatal_err:
 447   ((struct unix_conn *) (xprt->xp_p1))->strm_stat = XPRT_DIED;
 448   return -1;
 449 }
 450
 451 /*
 452  * writes data to the unix connection.
 453  * Any error is fatal and the connection is closed.
 454  */
 455 static int
 456 writeunix (char *xprtptr, char * buf, int len)
 457 {
 458   SVCXPRT *xprt = (SVCXPRT *) xprtptr;
 459   int i, cnt;
 460
 461   for (cnt = len; cnt > 0; cnt -= i, buf += i)
 462     {
 463       if ((i = __msgwrite (xprt->xp_sock, buf, cnt)) < 0)
 464         {
 465           ((struct unix_conn *) (xprt->xp_p1))->strm_stat = XPRT_DIED;
 466           return -1;
 467         }
 468     }
 469   return len;
 470 }
 471
 472 static enum xprt_stat
 473 svcunix_stat (SVCXPRT *xprt)
 474 {
 475   struct unix_conn *cd =
 476   (struct unix_conn *) (xprt->xp_p1);
 477
 478   if (cd->strm_stat == XPRT_DIED)
 479     return XPRT_DIED;
 480   if (!xdrrec_eof (&(cd->xdrs)))
 481     return XPRT_MOREREQS;
 482   return XPRT_IDLE;
 483 }
 484
 485 static bool_t
 486 svcunix_recv (SVCXPRT *xprt, struct rpc_msg *msg)
 487 {
 488   struct unix_conn *cd = (struct unix_conn *) (xprt->xp_p1);
 489   XDR *xdrs = &(cd->xdrs);
 490
 491   xdrs->x_op = XDR_DECODE;
 492   xdrrec_skiprecord (xdrs);
 493   if (xdr_callmsg (xdrs, msg))
 494     {
 495       cd->x_id = msg->rm_xid;
 496       /* set up verifiers */
 497 #ifdef SCM_CREDENTIALS
 498       msg->rm_call.cb_verf.oa_flavor = AUTH_UNIX;
 499       msg->rm_call.cb_verf.oa_base = (caddr_t) &cm;
 500       msg->rm_call.cb_verf.oa_length = sizeof (cm);
 501 #endif
 502       return TRUE;
 503     }
 504   cd->strm_stat = XPRT_DIED;    /* XXXX */
 505   return FALSE;
 506 }
 507
 508 static bool_t
 509 svcunix_getargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
 510 {
 511   return (*xdr_args) (&(((struct unix_conn *) (xprt->xp_p1))->xdrs),
 512                       args_ptr);
 513 }
 514
 515 static bool_t
 516 svcunix_freeargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
 517 {
 518   XDR *xdrs = &(((struct unix_conn *) (xprt->xp_p1))->xdrs);
 519
 520   xdrs->x_op = XDR_FREE;
 521   return (*xdr_args) (xdrs, args_ptr);
 522 }
 523
 524 static bool_t
 525 svcunix_reply (SVCXPRT *xprt, struct rpc_msg *msg)
 526 {
 527   struct unix_conn *cd = (struct unix_conn *) (xprt->xp_p1);
 528   XDR *xdrs = &(cd->xdrs);
 529   bool_t stat;
 530
 531   xdrs->x_op = XDR_ENCODE;
 532   msg->rm_xid = cd->x_id;
 533   stat = xdr_replymsg (xdrs, msg);
 534   (void) xdrrec_endofrecord (xdrs, TRUE);
 535   return stat;
 536 }