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 <libc-lock.h>
  52 #include <shlib-compat.h>
  53
  54 #define KEY_TIMEOUT     5       /* per-try timeout in seconds */
  55 #define KEY_NRETRY      12      /* number of retries */
  56
  57 #define debug(msg)              /* turn off debugging */
  58
  59 #ifndef SO_PASSCRED
  60 extern int _openchild (const char *command, FILE **fto, FILE **ffrom);
  61 #endif
  62
  63 static int key_call (u_long, xdrproc_t xdr_arg, char *,
  64                      xdrproc_t xdr_rslt, char *);
  65
  66 static const struct timeval trytimeout = {KEY_TIMEOUT, 0};
  67 static const struct timeval tottimeout = {KEY_TIMEOUT *KEY_NRETRY, 0};
  68
  69 int
  70 key_setsecret (char *secretkey)
  71 {
  72   keystatus status;
  73
  74   if (!key_call ((u_long) KEY_SET, (xdrproc_t) xdr_keybuf, secretkey,
  75                  (xdrproc_t) xdr_keystatus, (char *) &status))
  76     return -1;
  77   if (status != KEY_SUCCESS)
  78     {
  79       debug ("set status is nonzero");
  80       return -1;
  81     }
  82   return 0;
  83 }
  84 libc_hidden_nolink_sunrpc (key_setsecret, GLIBC_2_1)
  85
  86 /* key_secretkey_is_set() returns 1 if the keyserver has a secret key
  87  * stored for the caller's effective uid; it returns 0 otherwise
  88  *
  89  * N.B.:  The KEY_NET_GET key call is undocumented.  Applications shouldn't
  90  * be using it, because it allows them to get the user's secret key.
  91  */
  92 int
  93 key_secretkey_is_set (void)
  94 {
  95   struct key_netstres kres;
  96
  97   memset (&kres, 0, sizeof (kres));
  98   if (key_call ((u_long) KEY_NET_GET, (xdrproc_t) xdr_void,
  99                 (char *) NULL, (xdrproc_t) xdr_key_netstres,
 100                 (char *) &kres) &&
 101       (kres.status == KEY_SUCCESS) &&
 102       (kres.key_netstres_u.knet.st_priv_key[0] != 0))
 103     {
 104       /* avoid leaving secret key in memory */
 105       memset (kres.key_netstres_u.knet.st_priv_key, 0, HEXKEYBYTES);
 106       return 1;
 107     }
 108   return 0;
 109 }
 110 #ifdef EXPORT_RPC_SYMBOLS
 111 libc_hidden_def (key_secretkey_is_set)
 112 #else
 113 libc_hidden_nolink_sunrpc (key_secretkey_is_set, GLIBC_2_1)
 114 #endif
 115
 116 int
 117 key_encryptsession (char *remotename, des_block *deskey)
 118 {
 119   cryptkeyarg arg;
 120   cryptkeyres res;
 121
 122   arg.remotename = remotename;
 123   arg.deskey = *deskey;
 124   if (!key_call ((u_long) KEY_ENCRYPT, (xdrproc_t) xdr_cryptkeyarg,
 125                  (char *) &arg, (xdrproc_t) xdr_cryptkeyres,
 126                  (char *) &res))
 127     return -1;
 128
 129   if (res.status != KEY_SUCCESS)
 130     {
 131       debug ("encrypt status is nonzero");
 132       return -1;
 133     }
 134   *deskey = res.cryptkeyres_u.deskey;
 135   return 0;
 136 }
 137 libc_hidden_nolink_sunrpc (key_encryptsession, GLIBC_2_1)
 138
 139 int
 140 key_decryptsession (char *remotename, des_block *deskey)
 141 {
 142   cryptkeyarg arg;
 143   cryptkeyres res;
 144
 145   arg.remotename = remotename;
 146   arg.deskey = *deskey;
 147   if (!key_call ((u_long) KEY_DECRYPT, (xdrproc_t) xdr_cryptkeyarg,
 148                  (char *) &arg, (xdrproc_t) xdr_cryptkeyres,
 149                  (char *) &res))
 150     return -1;
 151   if (res.status != KEY_SUCCESS)
 152     {
 153       debug ("decrypt status is nonzero");
 154       return -1;
 155     }
 156   *deskey = res.cryptkeyres_u.deskey;
 157   return 0;
 158 }
 159 libc_hidden_nolink_sunrpc (key_decryptsession, GLIBC_2_1)
 160
 161 int
 162 key_encryptsession_pk (char *remotename, netobj *remotekey,
 163                        des_block *deskey)
 164 {
 165   cryptkeyarg2 arg;
 166   cryptkeyres res;
 167
 168   arg.remotename = remotename;
 169   arg.remotekey = *remotekey;
 170   arg.deskey = *deskey;
 171   if (!key_call ((u_long) KEY_ENCRYPT_PK, (xdrproc_t) xdr_cryptkeyarg2,
 172                  (char *) &arg, (xdrproc_t) xdr_cryptkeyres,
 173                  (char *) &res))
 174     return -1;
 175
 176   if (res.status != KEY_SUCCESS)
 177     {
 178       debug ("encrypt status is nonzero");
 179       return -1;
 180     }
 181   *deskey = res.cryptkeyres_u.deskey;
 182   return 0;
 183 }
 184 libc_hidden_nolink_sunrpc (key_encryptsession_pk, GLIBC_2_1)
 185
 186 int
 187 key_decryptsession_pk (char *remotename, netobj *remotekey,
 188                        des_block *deskey)
 189 {
 190   cryptkeyarg2 arg;
 191   cryptkeyres res;
 192
 193   arg.remotename = remotename;
 194   arg.remotekey = *remotekey;
 195   arg.deskey = *deskey;
 196   if (!key_call ((u_long) KEY_DECRYPT_PK, (xdrproc_t) xdr_cryptkeyarg2,
 197                  (char *) &arg, (xdrproc_t) xdr_cryptkeyres,
 198                  (char *) &res))
 199     return -1;
 200
 201   if (res.status != KEY_SUCCESS)
 202     {
 203       debug ("decrypt status is nonzero");
 204       return -1;
 205     }
 206   *deskey = res.cryptkeyres_u.deskey;
 207   return 0;
 208 }
 209 libc_hidden_nolink_sunrpc (key_decryptsession_pk, GLIBC_2_1)
 210
 211 int
 212 key_gendes (des_block *key)
 213 {
 214   struct sockaddr_in sin;
 215   CLIENT *client;
 216   int socket;
 217   enum clnt_stat stat;
 218
 219   sin.sin_family = AF_INET;
 220   sin.sin_port = 0;
 221   sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
 222   memset (sin.sin_zero, 0, sizeof (sin.sin_zero));
 223   socket = RPC_ANYSOCK;
 224   client = clntudp_bufcreate (&sin, (u_long) KEY_PROG, (u_long) KEY_VERS,
 225                               trytimeout, &socket, RPCSMALLMSGSIZE,
 226                               RPCSMALLMSGSIZE);
 227   if (client == NULL)
 228     return -1;
 229
 230   stat = clnt_call (client, KEY_GEN, (xdrproc_t) xdr_void, NULL,
 231                     (xdrproc_t) xdr_des_block, (caddr_t) key,
 232                     tottimeout);
 233   clnt_destroy (client);
 234   __close (socket);
 235   if (stat != RPC_SUCCESS)
 236     return -1;
 237
 238   return 0;
 239 }
 240 #ifdef EXPORT_RPC_SYMBOLS
 241 libc_hidden_def (key_gendes)
 242 #else
 243 libc_hidden_nolink_sunrpc (key_gendes, GLIBC_2_1)
 244 #endif
 245
 246 int
 247 key_setnet (struct key_netstarg *arg)
 248 {
 249   keystatus status;
 250
 251   if (!key_call ((u_long) KEY_NET_PUT, (xdrproc_t) xdr_key_netstarg,
 252                  (char *) arg,(xdrproc_t) xdr_keystatus,
 253                  (char *) &status))
 254     return -1;
 255
 256   if (status != KEY_SUCCESS)
 257     {
 258       debug ("key_setnet status is nonzero");
 259       return -1;
 260     }
 261   return 1;
 262 }
 263 libc_hidden_nolink_sunrpc (key_setnet, GLIBC_2_1)
 264
 265 int
 266 key_get_conv (char *pkey, des_block *deskey)
 267 {
 268   cryptkeyres res;
 269
 270   if (!key_call ((u_long) KEY_GET_CONV, (xdrproc_t) xdr_keybuf, pkey,
 271                  (xdrproc_t) xdr_cryptkeyres, (char *) &res))
 272     return -1;
 273
 274   if (res.status != KEY_SUCCESS)
 275     {
 276       debug ("get_conv status is nonzero");
 277       return -1;
 278     }
 279   *deskey = res.cryptkeyres_u.deskey;
 280   return 0;
 281 }
 282 libc_hidden_nolink_sunrpc (key_get_conv, GLIBC_2_1)
 283
 284 /*
 285  * Hack to allow the keyserver to use AUTH_DES (for authenticated
 286  * NIS+ calls, for example).  The only functions that get called
 287  * are key_encryptsession_pk, key_decryptsession_pk, and key_gendes.
 288  *
 289  * The approach is to have the keyserver fill in pointers to local
 290  * implementations of these functions, and to call those in key_call().
 291  */
 292
 293 cryptkeyres *(*__key_encryptsession_pk_LOCAL) (uid_t, char *);
 294 cryptkeyres *(*__key_decryptsession_pk_LOCAL) (uid_t, char *);
 295 des_block *(*__key_gendes_LOCAL) (uid_t, char *);
 296
 297 #ifndef SO_PASSCRED
 298 static int
 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   int 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 != 0)
 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 key_call_socket (u_long proc, xdrproc_t xdr_arg, char *arg,
 484                xdrproc_t xdr_rslt, char *rslt)
 485 {
 486   CLIENT *clnt;
 487   struct timeval wait_time;
 488   int result = 0;
 489
 490   __libc_lock_lock (keycall_lock);
 491   if ((proc == KEY_ENCRYPT_PK) || (proc == KEY_DECRYPT_PK) ||
 492       (proc == KEY_NET_GET) || (proc == KEY_NET_PUT) ||
 493       (proc == KEY_GET_CONV))
 494     clnt = getkeyserv_handle(2); /* talk to version 2 */
 495   else
 496     clnt = getkeyserv_handle(1); /* talk to version 1 */
 497
 498   if (clnt != NULL)
 499     {
 500       wait_time.tv_sec = TOTAL_TIMEOUT;
 501       wait_time.tv_usec = 0;
 502
 503       if (clnt_call (clnt, proc, xdr_arg, arg, xdr_rslt, rslt,
 504                      wait_time) == RPC_SUCCESS)
 505         result = 1;
 506     }
 507
 508   __libc_lock_unlock (keycall_lock);
 509
 510   return result;
 511 }
 512
 513
 514 /* returns 0 on failure, 1 on success */
 515 static int
 516 key_call (u_long proc, xdrproc_t xdr_arg, char *arg,
 517           xdrproc_t xdr_rslt, char *rslt)
 518 {
 519 #ifndef SO_PASSCRED
 520   static int use_keyenvoy;
 521 #endif
 522
 523   if (proc == KEY_ENCRYPT_PK && __key_encryptsession_pk_LOCAL)
 524     {
 525       cryptkeyres *res;
 526       res = (*__key_encryptsession_pk_LOCAL) (__geteuid (), arg);
 527       *(cryptkeyres *) rslt = *res;
 528       return 1;
 529     }
 530   else if (proc == KEY_DECRYPT_PK && __key_decryptsession_pk_LOCAL)
 531     {
 532       cryptkeyres *res;
 533       res = (*__key_decryptsession_pk_LOCAL) (__geteuid (), arg);
 534       *(cryptkeyres *) rslt = *res;
 535       return 1;
 536     }
 537   else if (proc == KEY_GEN && __key_gendes_LOCAL)
 538     {
 539       des_block *res;
 540       res = (*__key_gendes_LOCAL) (__geteuid (), 0);
 541       *(des_block *) rslt = *res;
 542       return 1;
 543     }
 544
 545 #ifdef SO_PASSCRED
 546   return key_call_socket (proc, xdr_arg, arg, xdr_rslt, rslt);
 547 #else
 548   if (!use_keyenvoy)
 549     {
 550       if (key_call_socket (proc, xdr_arg, arg, xdr_rslt, rslt))
 551         return 1;
 552       use_keyenvoy = 1;
 553     }
 554   return key_call_keyenvoy (proc, xdr_arg, arg, xdr_rslt, rslt);
 555 #endif
 556 }
 557
 558 #ifdef _RPC_THREAD_SAFE_
 559 void
 560 __rpc_thread_key_cleanup (void)
 561 {
 562         struct key_call_private *kcp = RPC_THREAD_VARIABLE(key_call_private_s);
 563
 564         if (kcp) {
 565                 if (kcp->client) {
 566                         if (kcp->client->cl_auth)
 567                                 auth_destroy (kcp->client->cl_auth);
 568                         clnt_destroy(kcp->client);
 569                 }
 570                 free (kcp);
 571         }
 572 }
 573 #endif /* _RPC_THREAD_SAFE_ */