sunrpc/key_call.c

   1 /*
   2  * Copyright (c) 2010, Oracle America, Inc.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  *     * Redistributions of source code must retain the above copyright
   9  *       notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  *       copyright notice, this list of conditions and the following
  12  *       disclaimer in the documentation and/or other materials
  13  *       provided with the distribution.
  14  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  15  *       contributors may be used to endorse or promote products derived
  16  *       from this software without specific prior written permission.
  17  *
  18  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  21  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  22  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  23  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  25  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  27  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  28  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31 /*
  32  * The original source is from the RPCSRC 4.0 package from Sun Microsystems.
  33  * The Interface to keyserver protocoll 2, RPC over AF_UNIX and Linux/doors
  34  * was added by Thorsten Kukuk <kukuk@suse.de>
  35  * Since the Linux/doors project was stopped, I doubt that this code will
  36  * ever be useful <kukuk@suse.de>.
  37  */
  38
  39 #include <stdio.h>
  40 #include <errno.h>
  41 #include <fcntl.h>
  42 #include <signal.h>
  43 #include <unistd.h>
  44 #include <string.h>
  45 #include <rpc/rpc.h>
  46 #include <rpc/auth.h>
  47 #include <sys/wait.h>
  48 #include <sys/param.h>
  49 #include <sys/socket.h>
  50 #include <rpc/key_prot.h>
  51 #include <bits/libc-lock.h>
  52
  53 #define KEY_TIMEOUT     5       /* per-try timeout in seconds */
  54 #define KEY_NRETRY      12      /* number of retries */
  55
  56 #define debug(msg)              /* turn off debugging */
  57
  58 #ifndef SO_PASSCRED
  59 extern int _openchild (const char *command, FILE **fto, FILE **ffrom);
  60 #endif
  61
  62 static int key_call (u_long, xdrproc_t xdr_arg, char *,
  63                      xdrproc_t xdr_rslt, char *) internal_function;
  64
  65 static const struct timeval trytimeout = {KEY_TIMEOUT, 0};
  66 static const struct timeval tottimeout = {KEY_TIMEOUT *KEY_NRETRY, 0};
  67
  68 int
  69 key_setsecret (char *secretkey)
  70 {
  71   keystatus status;
  72
  73   if (!key_call ((u_long) KEY_SET, (xdrproc_t) xdr_keybuf, secretkey,
  74                  (xdrproc_t) xdr_keystatus, (char *) &status))
  75     return -1;
  76   if (status != KEY_SUCCESS)
  77     {
  78       debug ("set status is nonzero");
  79       return -1;
  80     }
  81   return 0;
  82 }
  83 libc_hidden_nolink (key_setsecret, GLIBC_2_1)
  84
  85 /* key_secretkey_is_set() returns 1 if the keyserver has a secret key
  86  * stored for the caller's effective uid; it returns 0 otherwise
  87  *
  88  * N.B.:  The KEY_NET_GET key call is undocumented.  Applications shouldn't
  89  * be using it, because it allows them to get the user's secret key.
  90  */
  91 int
  92 key_secretkey_is_set (void)
  93 {
  94   struct key_netstres kres;
  95
  96   memset (&kres, 0, sizeof (kres));
  97   if (key_call ((u_long) KEY_NET_GET, (xdrproc_t) xdr_void,
  98                 (char *) NULL, (xdrproc_t) xdr_key_netstres,
  99                 (char *) &kres) &&
 100       (kres.status == KEY_SUCCESS) &&
 101       (kres.key_netstres_u.knet.st_priv_key[0] != 0))
 102     {
 103       /* avoid leaving secret key in memory */
 104       memset (kres.key_netstres_u.knet.st_priv_key, 0, HEXKEYBYTES);
 105       return 1;
 106     }
 107   return 0;
 108 }
 109 #ifdef EXPORT_RPC_SYMBOLS
 110 libc_hidden_def (key_secretkey_is_set)
 111 #else
 112 libc_hidden_nolink (key_secretkey_is_set, GLIBC_2_1)
 113 #endif
 114
 115 int
 116 key_encryptsession (char *remotename, des_block *deskey)
 117 {
 118   cryptkeyarg arg;
 119   cryptkeyres res;
 120
 121   arg.remotename = remotename;
 122   arg.deskey = *deskey;
 123   if (!key_call ((u_long) KEY_ENCRYPT, (xdrproc_t) xdr_cryptkeyarg,
 124                  (char *) &arg, (xdrproc_t) xdr_cryptkeyres,
 125                  (char *) &res))
 126     return -1;
 127
 128   if (res.status != KEY_SUCCESS)
 129     {
 130       debug ("encrypt status is nonzero");
 131       return -1;
 132     }
 133   *deskey = res.cryptkeyres_u.deskey;
 134   return 0;
 135 }
 136 libc_hidden_nolink (key_encryptsession, GLIBC_2_1)
 137
 138 int
 139 key_decryptsession (char *remotename, des_block *deskey)
 140 {
 141   cryptkeyarg arg;
 142   cryptkeyres res;
 143
 144   arg.remotename = remotename;
 145   arg.deskey = *deskey;
 146   if (!key_call ((u_long) KEY_DECRYPT, (xdrproc_t) xdr_cryptkeyarg,
 147                  (char *) &arg, (xdrproc_t) xdr_cryptkeyres,
 148                  (char *) &res))
 149     return -1;
 150   if (res.status != KEY_SUCCESS)
 151     {
 152       debug ("decrypt status is nonzero");
 153       return -1;
 154     }
 155   *deskey = res.cryptkeyres_u.deskey;
 156   return 0;
 157 }
 158 libc_hidden_nolink (key_decryptsession, GLIBC_2_1)
 159
 160 int
 161 key_encryptsession_pk (char *remotename, netobj *remotekey,
 162                        des_block *deskey)
 163 {
 164   cryptkeyarg2 arg;
 165   cryptkeyres res;
 166
 167   arg.remotename = remotename;
 168   arg.remotekey = *remotekey;
 169   arg.deskey = *deskey;
 170   if (!key_call ((u_long) KEY_ENCRYPT_PK, (xdrproc_t) xdr_cryptkeyarg2,
 171                  (char *) &arg, (xdrproc_t) xdr_cryptkeyres,
 172                  (char *) &res))
 173     return -1;
 174
 175   if (res.status != KEY_SUCCESS)
 176     {
 177       debug ("encrypt status is nonzero");
 178       return -1;
 179     }
 180   *deskey = res.cryptkeyres_u.deskey;
 181   return 0;
 182 }
 183 libc_hidden_nolink (key_encryptsession_pk, GLIBC_2_1)
 184
 185 int
 186 key_decryptsession_pk (char *remotename, netobj *remotekey,
 187                        des_block *deskey)
 188 {
 189   cryptkeyarg2 arg;
 190   cryptkeyres res;
 191
 192   arg.remotename = remotename;
 193   arg.remotekey = *remotekey;
 194   arg.deskey = *deskey;
 195   if (!key_call ((u_long) KEY_DECRYPT_PK, (xdrproc_t) xdr_cryptkeyarg2,
 196                  (char *) &arg, (xdrproc_t) xdr_cryptkeyres,
 197                  (char *) &res))
 198     return -1;
 199
 200   if (res.status != KEY_SUCCESS)
 201     {
 202       debug ("decrypt status is nonzero");
 203       return -1;
 204     }
 205   *deskey = res.cryptkeyres_u.deskey;
 206   return 0;
 207 }
 208 libc_hidden_nolink (key_decryptsession_pk, GLIBC_2_1)
 209
 210 int
 211 key_gendes (des_block *key)
 212 {
 213   struct sockaddr_in sin;
 214   CLIENT *client;
 215   int socket;
 216   enum clnt_stat stat;
 217
 218   sin.sin_family = AF_INET;
 219   sin.sin_port = 0;
 220   sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
 221   __bzero (sin.sin_zero, sizeof (sin.sin_zero));
 222   socket = RPC_ANYSOCK;
 223   client = clntudp_bufcreate (&sin, (u_long) KEY_PROG, (u_long) KEY_VERS,
 224                               trytimeout, &socket, RPCSMALLMSGSIZE,
 225                               RPCSMALLMSGSIZE);
 226   if (client == NULL)
 227     return -1;
 228
 229   stat = clnt_call (client, KEY_GEN, (xdrproc_t) xdr_void, NULL,
 230                     (xdrproc_t) xdr_des_block, (caddr_t) key,
 231                     tottimeout);
 232   clnt_destroy (client);
 233   __close (socket);
 234   if (stat != RPC_SUCCESS)
 235     return -1;
 236
 237   return 0;
 238 }
 239 #ifdef EXPORT_RPC_SYMBOLS
 240 libc_hidden_def (key_gendes)
 241 #else
 242 libc_hidden_nolink (key_gendes, GLIBC_2_1)
 243 #endif
 244
 245 int
 246 key_setnet (struct key_netstarg *arg)
 247 {
 248   keystatus status;
 249
 250   if (!key_call ((u_long) KEY_NET_PUT, (xdrproc_t) xdr_key_netstarg,
 251                  (char *) arg,(xdrproc_t) xdr_keystatus,
 252                  (char *) &status))
 253     return -1;
 254
 255   if (status != KEY_SUCCESS)
 256     {
 257       debug ("key_setnet status is nonzero");
 258       return -1;
 259     }
 260   return 1;
 261 }
 262 libc_hidden_nolink (key_setnet, GLIBC_2_1)
 263
 264 int
 265 key_get_conv (char *pkey, des_block *deskey)
 266 {
 267   cryptkeyres res;
 268
 269   if (!key_call ((u_long) KEY_GET_CONV, (xdrproc_t) xdr_keybuf, pkey,
 270                  (xdrproc_t) xdr_cryptkeyres, (char *) &res))
 271     return -1;
 272
 273   if (res.status != KEY_SUCCESS)
 274     {
 275       debug ("get_conv status is nonzero");
 276       return -1;
 277     }
 278   *deskey = res.cryptkeyres_u.deskey;
 279   return 0;
 280 }
 281 libc_hidden_nolink (key_get_conv, GLIBC_2_1)
 282
 283 /*
 284  * Hack to allow the keyserver to use AUTH_DES (for authenticated
 285  * NIS+ calls, for example).  The only functions that get called
 286  * are key_encryptsession_pk, key_decryptsession_pk, and key_gendes.
 287  *
 288  * The approach is to have the keyserver fill in pointers to local
 289  * implementations of these functions, and to call those in key_call().
 290  */
 291
 292 cryptkeyres *(*__key_encryptsession_pk_LOCAL) (uid_t, char *);
 293 cryptkeyres *(*__key_decryptsession_pk_LOCAL) (uid_t, char *);
 294 des_block *(*__key_gendes_LOCAL) (uid_t, char *);
 295
 296 #ifndef SO_PASSCRED
 297 static int
 298 internal_function
 299 key_call_keyenvoy (u_long proc, xdrproc_t xdr_arg, char *arg,
 300                    xdrproc_t xdr_rslt, char *rslt)
 301 {
 302   XDR xdrargs;
 303   XDR xdrrslt;
 304   FILE *fargs;
 305   FILE *frslt;
 306   sigset_t oldmask, mask;
 307   union wait status;
 308   int pid;
 309   int success;
 310   uid_t ruid;
 311   uid_t euid;
 312   static const char MESSENGER[] = "/usr/etc/keyenvoy";
 313
 314   success = 1;
 315   sigemptyset (&mask);
 316   sigaddset (&mask, SIGCHLD);
 317   __sigprocmask (SIG_BLOCK, &mask, &oldmask);
 318
 319   /*
 320    * We are going to exec a set-uid program which makes our effective uid
 321    * zero, and authenticates us with our real uid. We need to make the
 322    * effective uid be the real uid for the setuid program, and
 323    * the real uid be the effective uid so that we can change things back.
 324    */
 325   euid = __geteuid ();
 326   ruid = __getuid ();
 327   __setreuid (euid, ruid);
 328   pid = _openchild (MESSENGER, &fargs, &frslt);
 329   __setreuid (ruid, euid);
 330   if (pid < 0)
 331     {
 332       debug ("open_streams");
 333       __sigprocmask (SIG_SETMASK, &oldmask, NULL);
 334       return (0);
 335     }
 336   xdrstdio_create (&xdrargs, fargs, XDR_ENCODE);
 337   xdrstdio_create (&xdrrslt, frslt, XDR_DECODE);
 338
 339   if (!xdr_u_long (&xdrargs, &proc) || !(*xdr_arg) (&xdrargs, arg))
 340     {
 341       debug ("xdr args");
 342       success = 0;
 343     }
 344   fclose (fargs);
 345
 346   if (success && !(*xdr_rslt) (&xdrrslt, rslt))
 347     {
 348       debug ("xdr rslt");
 349       success = 0;
 350     }
 351   fclose(frslt);
 352
 353  wait_again:
 354   if (__wait4 (pid, &status, 0, NULL) < 0)
 355     {
 356       if (errno == EINTR)
 357         goto wait_again;
 358       debug ("wait4");
 359       if (errno == ECHILD || errno == ESRCH)
 360         perror ("wait");
 361       else
 362         success = 0;
 363     }
 364   else
 365     if (status.w_retcode)
 366       {
 367         debug ("wait4 1");
 368         success = 0;
 369       }
 370   __sigprocmask (SIG_SETMASK, &oldmask, NULL);
 371
 372   return success;
 373 }
 374 #endif
 375
 376 struct  key_call_private {
 377   CLIENT  *client;        /* Client handle */
 378   pid_t   pid;            /* process-id at moment of creation */
 379   uid_t   uid;            /* user-id at last authorization */
 380 };
 381 #ifdef _RPC_THREAD_SAFE_
 382 #define key_call_private_main RPC_THREAD_VARIABLE(key_call_private_s)
 383 #else
 384 static struct key_call_private *key_call_private_main;
 385 #endif
 386 __libc_lock_define_initialized (static, keycall_lock)
 387
 388 /*
 389  * Keep the handle cached.  This call may be made quite often.
 390  */
 391 static CLIENT *
 392 getkeyserv_handle (int vers)
 393 {
 394   struct key_call_private *kcp = key_call_private_main;
 395   struct timeval wait_time;
 396   int fd;
 397   struct sockaddr_un name;
 398   socklen_t namelen = sizeof(struct sockaddr_un);
 399
 400 #define TOTAL_TIMEOUT   30      /* total timeout talking to keyserver */
 401 #define TOTAL_TRIES     5       /* Number of tries */
 402
 403   if (kcp == (struct key_call_private *)NULL)
 404     {
 405       kcp = (struct key_call_private *)malloc (sizeof (*kcp));
 406       if (kcp == (struct key_call_private *)NULL)
 407         return (CLIENT *) NULL;
 408
 409       key_call_private_main = kcp;
 410       kcp->client = NULL;
 411     }
 412
 413   /* if pid has changed, destroy client and rebuild */
 414   if (kcp->client != NULL && kcp->pid != __getpid ())
 415     {
 416       auth_destroy (kcp->client->cl_auth);
 417       clnt_destroy (kcp->client);
 418       kcp->client = NULL;
 419     }
 420
 421   if (kcp->client != NULL)
 422     {
 423       /* if other side closed socket, build handle again */
 424       clnt_control (kcp->client, CLGET_FD, (char *)&fd);
 425       if (__getpeername (fd,(struct sockaddr *)&name,&namelen) == -1)
 426         {
 427           auth_destroy (kcp->client->cl_auth);
 428           clnt_destroy (kcp->client);
 429           kcp->client = NULL;
 430         }
 431     }
 432
 433   if (kcp->client != NULL)
 434     {
 435       /* if uid has changed, build client handle again */
 436       if (kcp->uid != __geteuid ())
 437         {
 438         kcp->uid = __geteuid ();
 439         auth_destroy (kcp->client->cl_auth);
 440         kcp->client->cl_auth =
 441           authunix_create ((char *)"", kcp->uid, 0, 0, NULL);
 442         if (kcp->client->cl_auth == NULL)
 443           {
 444             clnt_destroy (kcp->client);
 445             kcp->client = NULL;
 446             return ((CLIENT *) NULL);
 447           }
 448         }
 449       /* Change the version number to the new one */
 450       clnt_control (kcp->client, CLSET_VERS, (void *)&vers);
 451       return kcp->client;
 452     }
 453
 454   if ((kcp->client == (CLIENT *) NULL))
 455     /* Use the AF_UNIX transport */
 456     kcp->client = clnt_create ("/var/run/keyservsock", KEY_PROG, vers, "unix");
 457
 458   if (kcp->client == (CLIENT *) NULL)
 459     return (CLIENT *) NULL;
 460
 461   kcp->uid = __geteuid ();
 462   kcp->pid = __getpid ();
 463   kcp->client->cl_auth = authunix_create ((char *)"", kcp->uid, 0, 0, NULL);
 464   if (kcp->client->cl_auth == NULL)
 465     {
 466       clnt_destroy (kcp->client);
 467       kcp->client = NULL;
 468       return (CLIENT *) NULL;
 469     }
 470
 471   wait_time.tv_sec = TOTAL_TIMEOUT/TOTAL_TRIES;
 472   wait_time.tv_usec = 0;
 473   clnt_control (kcp->client, CLSET_RETRY_TIMEOUT,
 474                 (char *)&wait_time);
 475   if (clnt_control (kcp->client, CLGET_FD, (char *)&fd))
 476     __fcntl (fd, F_SETFD, FD_CLOEXEC);  /* make it "close on exec" */
 477
 478   return kcp->client;
 479 }
 480
 481 /* returns  0 on failure, 1 on success */
 482 static int
 483 internal_function
 484 key_call_socket (u_long proc, xdrproc_t xdr_arg, char *arg,
 485                xdrproc_t xdr_rslt, char *rslt)
 486 {
 487   CLIENT *clnt;
 488   struct timeval wait_time;
 489   int result = 0;
 490
 491   __libc_lock_lock (keycall_lock);
 492   if ((proc == KEY_ENCRYPT_PK) || (proc == KEY_DECRYPT_PK) ||
 493       (proc == KEY_NET_GET) || (proc == KEY_NET_PUT) ||
 494       (proc == KEY_GET_CONV))
 495     clnt = getkeyserv_handle(2); /* talk to version 2 */
 496   else
 497     clnt = getkeyserv_handle(1); /* talk to version 1 */
 498
 499   if (clnt != NULL)
 500     {
 501       wait_time.tv_sec = TOTAL_TIMEOUT;
 502       wait_time.tv_usec = 0;
 503
 504       if (clnt_call (clnt, proc, xdr_arg, arg, xdr_rslt, rslt,
 505                      wait_time) == RPC_SUCCESS)
 506         result = 1;
 507     }
 508
 509   __libc_lock_unlock (keycall_lock);
 510
 511   return result;
 512 }
 513
 514
 515 /* returns 0 on failure, 1 on success */
 516 static int
 517 internal_function
 518 key_call (u_long proc, xdrproc_t xdr_arg, char *arg,
 519           xdrproc_t xdr_rslt, char *rslt)
 520 {
 521 #ifndef SO_PASSCRED
 522   static int use_keyenvoy;
 523 #endif
 524
 525   if (proc == KEY_ENCRYPT_PK && __key_encryptsession_pk_LOCAL)
 526     {
 527       cryptkeyres *res;
 528       res = (*__key_encryptsession_pk_LOCAL) (__geteuid (), arg);
 529       *(cryptkeyres *) rslt = *res;
 530       return 1;
 531     }
 532   else if (proc == KEY_DECRYPT_PK && __key_decryptsession_pk_LOCAL)
 533     {
 534       cryptkeyres *res;
 535       res = (*__key_decryptsession_pk_LOCAL) (__geteuid (), arg);
 536       *(cryptkeyres *) rslt = *res;
 537       return 1;
 538     }
 539   else if (proc == KEY_GEN && __key_gendes_LOCAL)
 540     {
 541       des_block *res;
 542       res = (*__key_gendes_LOCAL) (__geteuid (), 0);
 543       *(des_block *) rslt = *res;
 544       return 1;
 545     }
 546
 547 #ifdef SO_PASSCRED
 548   return key_call_socket (proc, xdr_arg, arg, xdr_rslt, rslt);
 549 #else
 550   if (!use_keyenvoy)
 551     {
 552       if (key_call_socket (proc, xdr_arg, arg, xdr_rslt, rslt))
 553         return 1;
 554       use_keyenvoy = 1;
 555     }
 556   return key_call_keyenvoy (proc, xdr_arg, arg, xdr_rslt, rslt);
 557 #endif
 558 }
 559
 560 #ifdef _RPC_THREAD_SAFE_
 561 void
 562 __rpc_thread_key_cleanup (void)
 563 {
 564         struct key_call_private *kcp = RPC_THREAD_VARIABLE(key_call_private_s);
 565
 566         if (kcp) {
 567                 if (kcp->client) {
 568                         if (kcp->client->cl_auth)
 569                                 auth_destroy (kcp->client->cl_auth);
 570                         clnt_destroy(kcp->client);
 571                 }
 572                 free (kcp);
 573         }
 574 }
 575 #endif /* _RPC_THREAD_SAFE_ */