lib/libc/rpc/auth_unix.c

   1 /*      $NetBSD: auth_unix.c,v 1.26 2014/10/18 08:33:23 snj Exp $       */
   2
   3 /*
   4  * Copyright (c) 2010, Oracle America, Inc.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are
   8  * met:
   9  *
  10  *     * Redistributions of source code must retain the above copyright
  11  *       notice, this list of conditions and the following disclaimer.
  12  *     * Redistributions in binary form must reproduce the above
  13  *       copyright notice, this list of conditions and the following
  14  *       disclaimer in the documentation and/or other materials
  15  *       provided with the distribution.
  16  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  17  *       contributors may be used to endorse or promote products derived
  18  *       from this software without specific prior written permission.
  19  *
  20  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  23  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  24  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  25  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  27  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  29  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  30  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <sys/cdefs.h>
  35 #if defined(LIBC_SCCS) && !defined(lint)
  36 #if 0
  37 static char *sccsid = "@(#)auth_unix.c 1.19 87/08/11 Copyr 1984 Sun Micro";
  38 static char *sccsid = "@(#)auth_unix.c  2.2 88/08/01 4.0 RPCSRC";
  39 #else
  40 __RCSID("$NetBSD: auth_unix.c,v 1.26 2014/10/18 08:33:23 snj Exp $");
  41 #endif
  42 #endif
  43
  44 /*
  45  * auth_unix.c, Implements UNIX style authentication parameters.
  46  *
  47  * Copyright (C) 1984, Sun Microsystems, Inc.
  48  *
  49  * The system is very weak.  The client uses no encryption for its
  50  * credentials and only sends null verifiers.  The server sends backs
  51  * null verifiers or optionally a verifier that suggests a new short hand
  52  * for the credentials.
  53  *
  54  */
  55
  56 #include "namespace.h"
  57 #include "reentrant.h"
  58 #include <sys/param.h>
  59
  60 #include <assert.h>
  61 #include <err.h>
  62 #include <stdio.h>
  63 #include <stdlib.h>
  64 #include <string.h>
  65 #include <unistd.h>
  66
  67 #include <rpc/types.h>
  68 #include <rpc/xdr.h>
  69 #include <rpc/auth.h>
  70 #include <rpc/auth_unix.h>
  71
  72 #ifdef __weak_alias
  73 __weak_alias(authunix_create,_authunix_create)
  74 __weak_alias(authunix_create_default,_authunix_create_default)
  75 #endif
  76
  77
  78 /* auth_unix.c */
  79 static void authunix_nextverf(AUTH *);
  80 static bool_t authunix_marshal(AUTH *, XDR *);
  81 static bool_t authunix_validate(AUTH *, struct opaque_auth *);
  82 static bool_t authunix_refresh(AUTH *);
  83 static void authunix_destroy(AUTH *);
  84 static void marshal_new_auth(AUTH *);
  85 static const struct auth_ops *authunix_ops(void);
  86
  87 /*
  88  * This struct is pointed to by the ah_private field of an auth_handle.
  89  */
  90 struct audata {
  91         struct opaque_auth      au_origcred;    /* original credentials */
  92         struct opaque_auth      au_shcred;      /* short hand cred */
  93         u_long                  au_shfaults;    /* short hand cache faults */
  94         char                    au_marshed[MAX_AUTH_BYTES];
  95         u_int                   au_mpos;        /* xdr pos at end of marshed */
  96 };
  97 #define AUTH_PRIVATE(auth)      ((struct audata *)auth->ah_private)
  98
  99 /*
 100  * Create a unix style authenticator.
 101  * Returns an auth handle with the given stuff in it.
 102  */
 103 AUTH *
 104 authunix_create(char *machname, int uid, int gid, int len, int *aup_gids)
 105 {
 106         struct authunix_parms aup;
 107         char mymem[MAX_AUTH_BYTES];
 108         struct timeval now;
 109         XDR xdrs;
 110         AUTH *auth;
 111         struct audata *au;
 112
 113         /*
 114          * Allocate and set up auth handle
 115          */
 116         au = NULL;
 117         auth = mem_alloc(sizeof(*auth));
 118 #ifndef KERNEL
 119         if (auth == NULL) {
 120                 warn("%s: out of memory", __func__);
 121                 goto cleanup_authunix_create;
 122         }
 123 #endif
 124         au = mem_alloc(sizeof(*au));
 125 #ifndef KERNEL
 126         if (au == NULL) {
 127                 warn("%s: out of memory", __func__);
 128                 goto cleanup_authunix_create;
 129         }
 130 #endif
 131         auth->ah_ops = authunix_ops();
 132         auth->ah_private = au;
 133         auth->ah_verf = au->au_shcred = _null_auth;
 134         au->au_shfaults = 0;
 135         au->au_origcred.oa_base = NULL;
 136
 137         /*
 138          * fill in param struct from the given params
 139          */
 140         (void)gettimeofday(&now, NULL);
 141         aup.aup_time = (u_long)now.tv_sec;      /* XXX: truncate on 32 bit */
 142         aup.aup_machname = machname;
 143         aup.aup_uid = uid;
 144         aup.aup_gid = gid;
 145         aup.aup_len = (u_int)len;
 146         aup.aup_gids = aup_gids;
 147
 148         /*
 149          * Serialize the parameters into origcred
 150          */
 151         xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE);
 152         if (! xdr_authunix_parms(&xdrs, &aup))
 153                 abort();
 154         au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs);
 155         au->au_origcred.oa_flavor = AUTH_UNIX;
 156 #ifdef KERNEL
 157         au->au_origcred.oa_base = mem_alloc((size_t)len);
 158 #else
 159         if ((au->au_origcred.oa_base = mem_alloc((size_t)len)) == NULL) {
 160                 warn("%s: out of memory", __func__);
 161                 goto cleanup_authunix_create;
 162         }
 163 #endif
 164         memmove(au->au_origcred.oa_base, mymem, (size_t)len);
 165
 166         /*
 167          * set auth handle to reflect new cred.
 168          */
 169         auth->ah_cred = au->au_origcred;
 170         marshal_new_auth(auth);
 171         return (auth);
 172 #ifndef KERNEL
 173  cleanup_authunix_create:
 174         if (auth)
 175                 mem_free(auth, sizeof(*auth));
 176         if (au) {
 177                 if (au->au_origcred.oa_base)
 178                         mem_free(au->au_origcred.oa_base, (u_int)len);
 179                 mem_free(au, sizeof(*au));
 180         }
 181         return (NULL);
 182 #endif
 183 }
 184
 185 /*
 186  * Returns an auth handle with parameters determined by doing lots of
 187  * syscalls.
 188  */
 189 AUTH *
 190 authunix_create_default(void)
 191 {
 192         int len;
 193         char machname[MAXHOSTNAMELEN + 1];
 194         uid_t uid;
 195         gid_t gid;
 196         gid_t gids[NGRPS];
 197
 198         if (gethostname(machname, sizeof machname) == -1)
 199                 abort();
 200         machname[sizeof(machname) - 1] = 0;
 201         uid = geteuid();
 202         gid = getegid();
 203         if ((len = getgroups(NGRPS, gids)) < 0)
 204                 abort();
 205         /* XXX: interface problem; those should all have been unsigned */
 206         return (authunix_create(machname, (int)uid, (int)gid, len,
 207             (int *)gids));
 208 }
 209
 210 /*
 211  * authunix operations
 212  */
 213
 214 /* ARGSUSED */
 215 static void
 216 authunix_nextverf(AUTH *auth)
 217 {
 218         /* no action necessary */
 219 }
 220
 221 static bool_t
 222 authunix_marshal(AUTH *auth, XDR *xdrs)
 223 {
 224         struct audata *au;
 225
 226         _DIAGASSERT(auth != NULL);
 227         _DIAGASSERT(xdrs != NULL);
 228
 229         au = AUTH_PRIVATE(auth);
 230         return (XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos));
 231 }
 232
 233 static bool_t
 234 authunix_validate(AUTH *auth, struct opaque_auth *verf)
 235 {
 236         struct audata *au;
 237         XDR xdrs;
 238
 239         _DIAGASSERT(auth != NULL);
 240         _DIAGASSERT(verf != NULL);
 241
 242         if (verf->oa_flavor == AUTH_SHORT) {
 243                 au = AUTH_PRIVATE(auth);
 244                 xdrmem_create(&xdrs, verf->oa_base, verf->oa_length,
 245                     XDR_DECODE);
 246
 247                 if (au->au_shcred.oa_base != NULL) {
 248                         mem_free(au->au_shcred.oa_base,
 249                             au->au_shcred.oa_length);
 250                         au->au_shcred.oa_base = NULL;
 251                 }
 252                 if (xdr_opaque_auth(&xdrs, &au->au_shcred)) {
 253                         auth->ah_cred = au->au_shcred;
 254                 } else {
 255                         xdrs.x_op = XDR_FREE;
 256                         (void)xdr_opaque_auth(&xdrs, &au->au_shcred);
 257                         au->au_shcred.oa_base = NULL;
 258                         auth->ah_cred = au->au_origcred;
 259                 }
 260                 marshal_new_auth(auth);
 261         }
 262         return (TRUE);
 263 }
 264
 265 static bool_t
 266 authunix_refresh(AUTH *auth)
 267 {
 268         struct audata *au = AUTH_PRIVATE(auth);
 269         struct authunix_parms aup;
 270         struct timeval now;
 271         XDR xdrs;
 272         int stat;
 273
 274         _DIAGASSERT(auth != NULL);
 275
 276         if (auth->ah_cred.oa_base == au->au_origcred.oa_base) {
 277                 /* there is no hope.  Punt */
 278                 return (FALSE);
 279         }
 280         au->au_shfaults++;
 281
 282         /* first deserialize the creds back into a struct authunix_parms */
 283         aup.aup_machname = NULL;
 284         aup.aup_gids = NULL;
 285         xdrmem_create(&xdrs, au->au_origcred.oa_base,
 286             au->au_origcred.oa_length, XDR_DECODE);
 287         stat = xdr_authunix_parms(&xdrs, &aup);
 288         if (! stat)
 289                 goto done;
 290
 291         /* update the time and serialize in place */
 292         (void)gettimeofday(&now, NULL);
 293         aup.aup_time = (u_long)now.tv_sec;      /* XXX: truncate on 32 bit */
 294         xdrs.x_op = XDR_ENCODE;
 295         XDR_SETPOS(&xdrs, 0);
 296         stat = xdr_authunix_parms(&xdrs, &aup);
 297         if (! stat)
 298                 goto done;
 299         auth->ah_cred = au->au_origcred;
 300         marshal_new_auth(auth);
 301 done:
 302         /* free the struct authunix_parms created by deserializing */
 303         xdrs.x_op = XDR_FREE;
 304         (void)xdr_authunix_parms(&xdrs, &aup);
 305         XDR_DESTROY(&xdrs);
 306         return (stat);
 307 }
 308
 309 static void
 310 authunix_destroy(AUTH *auth)
 311 {
 312         struct audata *au;
 313
 314         _DIAGASSERT(auth != NULL);
 315
 316         au = AUTH_PRIVATE(auth);
 317         mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length);
 318
 319         if (au->au_shcred.oa_base != NULL)
 320                 mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length);
 321
 322         mem_free(auth->ah_private, sizeof(struct audata));
 323
 324         if (auth->ah_verf.oa_base != NULL)
 325                 mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length);
 326
 327         mem_free(auth, sizeof(*auth));
 328 }
 329
 330 /*
 331  * Marshals (pre-serializes) an auth struct.
 332  * sets private data, au_marshed and au_mpos
 333  */
 334 static void
 335 marshal_new_auth(AUTH *auth)
 336 {
 337         XDR     xdr_stream;
 338         XDR     *xdrs = &xdr_stream;
 339         struct audata *au;
 340
 341         _DIAGASSERT(auth != NULL);
 342
 343         au = AUTH_PRIVATE(auth);
 344         xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE);
 345         if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) ||
 346             (! xdr_opaque_auth(xdrs, &(auth->ah_verf))))
 347                 warnx("%s: Fatal marshalling problem", __func__);
 348         else
 349                 au->au_mpos = XDR_GETPOS(xdrs);
 350         XDR_DESTROY(xdrs);
 351 }
 352
 353 static const struct auth_ops *
 354 authunix_ops(void)
 355 {
 356         static struct auth_ops ops;
 357 #ifdef _REENTRANT
 358         extern mutex_t ops_lock;
 359 #endif
 360
 361         /* VARIABLES PROTECTED BY ops_lock: ops */
 362
 363         mutex_lock(&ops_lock);
 364         if (ops.ah_nextverf == NULL) {
 365                 ops.ah_nextverf = authunix_nextverf;
 366                 ops.ah_marshal = authunix_marshal;
 367                 ops.ah_validate = authunix_validate;
 368                 ops.ah_refresh = authunix_refresh;
 369                 ops.ah_destroy = authunix_destroy;
 370         }
 371         mutex_unlock(&ops_lock);
 372         return (&ops);
 373 }