The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/rpc/auth_unix.c

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    1 /*      $NetBSD: auth_unix.c,v 1.18 2000/07/06 03:03:30 christos Exp $  */
    2 
    3 /*
    4  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
    5  * unrestricted use provided that this legend is included on all tape
    6  * media and as a part of the software program in whole or part.  Users
    7  * may copy or modify Sun RPC without charge, but are not authorized
    8  * to license or distribute it to anyone else except as part of a product or
    9  * program developed by the user.
   10  *
   11  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
   12  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
   13  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
   14  *
   15  * Sun RPC is provided with no support and without any obligation on the
   16  * part of Sun Microsystems, Inc. to assist in its use, correction,
   17  * modification or enhancement.
   18  *
   19  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
   20  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
   21  * OR ANY PART THEREOF.
   22  *
   23  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
   24  * or profits or other special, indirect and consequential damages, even if
   25  * Sun has been advised of the possibility of such damages.
   26  *
   27  * Sun Microsystems, Inc.
   28  * 2550 Garcia Avenue
   29  * Mountain View, California  94043
   30  */
   31 
   32 #if defined(LIBC_SCCS) && !defined(lint)
   33 static char *sccsid2 = "@(#)auth_unix.c 1.19 87/08/11 Copyr 1984 Sun Micro";
   34 static char *sccsid = "@(#)auth_unix.c  2.2 88/08/01 4.0 RPCSRC";
   35 #endif
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD: releng/7.4/sys/rpc/auth_unix.c 181328 2008-08-05 10:35:51Z dfr $");
   38 
   39 /*
   40  * auth_unix.c, Implements UNIX style authentication parameters.
   41  *
   42  * Copyright (C) 1984, Sun Microsystems, Inc.
   43  *
   44  * The system is very weak.  The client uses no encryption for it's
   45  * credentials and only sends null verifiers.  The server sends backs
   46  * null verifiers or optionally a verifier that suggests a new short hand
   47  * for the credentials.
   48  *
   49  */
   50 
   51 #include <sys/param.h>
   52 #include <sys/systm.h>
   53 #include <sys/hash.h>
   54 #include <sys/kernel.h>
   55 #include <sys/lock.h>
   56 #include <sys/malloc.h>
   57 #include <sys/refcount.h>
   58 #include <sys/pcpu.h>
   59 #include <sys/sx.h>
   60 #include <sys/ucred.h>
   61 
   62 #include <rpc/types.h>
   63 #include <rpc/xdr.h>
   64 #include <rpc/auth.h>
   65 
   66 #include <rpc/rpc_com.h>
   67 
   68 /* auth_unix.c */
   69 static void authunix_nextverf (AUTH *);
   70 static bool_t authunix_marshal (AUTH *, XDR *);
   71 static bool_t authunix_validate (AUTH *, struct opaque_auth *);
   72 static bool_t authunix_refresh (AUTH *, void *);
   73 static void authunix_destroy (AUTH *);
   74 static void marshal_new_auth (AUTH *);
   75 
   76 static struct auth_ops authunix_ops = {
   77         .ah_nextverf =          authunix_nextverf,
   78         .ah_marshal =           authunix_marshal,
   79         .ah_validate =          authunix_validate,
   80         .ah_refresh =           authunix_refresh,
   81         .ah_destroy =           authunix_destroy
   82 };
   83 
   84 /*
   85  * This struct is pointed to by the ah_private field of an auth_handle.
   86  */
   87 struct audata {
   88         TAILQ_ENTRY(audata)     au_link;
   89         TAILQ_ENTRY(audata)     au_alllink;
   90         volatile u_int          au_refs;
   91         struct xucred           au_xcred;
   92         struct opaque_auth      au_origcred;    /* original credentials */
   93         struct opaque_auth      au_shcred;      /* short hand cred */
   94         u_long                  au_shfaults;    /* short hand cache faults */
   95         char                    au_marshed[MAX_AUTH_BYTES];
   96         u_int                   au_mpos;        /* xdr pos at end of marshed */
   97         AUTH                    *au_auth;       /* link back to AUTH */
   98 };
   99 TAILQ_HEAD(audata_list, audata);
  100 #define AUTH_PRIVATE(auth)      ((struct audata *)auth->ah_private)
  101 
  102 #define AUTH_UNIX_HASH_SIZE     16
  103 #define AUTH_UNIX_MAX           256
  104 static struct audata_list auth_unix_cache[AUTH_UNIX_HASH_SIZE];
  105 static struct audata_list auth_unix_all;
  106 static struct sx auth_unix_lock;
  107 static int auth_unix_count;
  108 
  109 static void
  110 authunix_init(void *dummy)
  111 {
  112         int i;
  113 
  114         for (i = 0; i < AUTH_UNIX_HASH_SIZE; i++)
  115                 TAILQ_INIT(&auth_unix_cache[i]);
  116         TAILQ_INIT(&auth_unix_all);
  117         sx_init(&auth_unix_lock, "auth_unix_lock");
  118 }
  119 SYSINIT(authunix_init, SI_SUB_KMEM, SI_ORDER_ANY, authunix_init, NULL);
  120 
  121 /*
  122  * Create a unix style authenticator.
  123  * Returns an auth handle with the given stuff in it.
  124  */
  125 AUTH *
  126 authunix_create(struct ucred *cred)
  127 {
  128         uint32_t h, th;
  129         struct xucred xcr;
  130         char mymem[MAX_AUTH_BYTES];
  131         XDR xdrs;
  132         AUTH *auth;
  133         struct audata *au, *tau;
  134         struct timeval now;
  135         uint32_t time;
  136         int len;
  137 
  138         if (auth_unix_count > AUTH_UNIX_MAX) {
  139                 while (auth_unix_count > AUTH_UNIX_MAX) {
  140                         sx_xlock(&auth_unix_lock);
  141                         tau = TAILQ_FIRST(&auth_unix_all);
  142                         th = HASHSTEP(HASHINIT, tau->au_xcred.cr_uid)
  143                                 % AUTH_UNIX_HASH_SIZE;
  144                         TAILQ_REMOVE(&auth_unix_cache[th], tau, au_link);
  145                         TAILQ_REMOVE(&auth_unix_all, tau, au_alllink);
  146                         auth_unix_count--;
  147                         sx_xunlock(&auth_unix_lock);
  148                         AUTH_DESTROY(tau->au_auth);
  149                 }
  150         }
  151 
  152         /*
  153          * Hash the uid to see if we already have an AUTH with this cred.
  154          */
  155         h = HASHSTEP(HASHINIT, cred->cr_uid) % AUTH_UNIX_HASH_SIZE;
  156         cru2x(cred, &xcr);
  157 again:
  158         sx_slock(&auth_unix_lock);
  159         TAILQ_FOREACH(au, &auth_unix_cache[h], au_link) {
  160                 if (!memcmp(&xcr, &au->au_xcred, sizeof(xcr))) {
  161                         refcount_acquire(&au->au_refs);
  162                         if (sx_try_upgrade(&auth_unix_lock)) {
  163                                 /*
  164                                  * Keep auth_unix_all LRU sorted.
  165                                  */
  166                                 TAILQ_REMOVE(&auth_unix_all, au, au_alllink);
  167                                 TAILQ_INSERT_TAIL(&auth_unix_all, au,
  168                                     au_alllink);
  169                                 sx_xunlock(&auth_unix_lock);
  170                         } else {
  171                                 sx_sunlock(&auth_unix_lock);
  172                         }
  173                         return (au->au_auth);
  174                 }
  175         }
  176 
  177         sx_sunlock(&auth_unix_lock);
  178 
  179         /*
  180          * Allocate and set up auth handle
  181          */
  182         au = NULL;
  183         auth = mem_alloc(sizeof(*auth));
  184         au = mem_alloc(sizeof(*au));
  185         auth->ah_ops = &authunix_ops;
  186         auth->ah_private = (caddr_t)au;
  187         auth->ah_verf = au->au_shcred = _null_auth;
  188         refcount_init(&au->au_refs, 1);
  189         au->au_xcred = xcr;
  190         au->au_shfaults = 0;
  191         au->au_origcred.oa_base = NULL;
  192         au->au_auth = auth;
  193 
  194         getmicrotime(&now);
  195         time = now.tv_sec;
  196 
  197         /*
  198          * Serialize the parameters into origcred
  199          */
  200         xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE);
  201         cru2x(cred, &xcr);
  202         if (! xdr_authunix_parms(&xdrs, &time, &xcr)) 
  203                 panic("authunix_create: failed to encode creds");
  204         au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs);
  205         au->au_origcred.oa_flavor = AUTH_UNIX;
  206         au->au_origcred.oa_base = mem_alloc((u_int) len);
  207         memcpy(au->au_origcred.oa_base, mymem, (size_t)len);
  208 
  209         /*
  210          * set auth handle to reflect new cred.
  211          */
  212         auth->ah_cred = au->au_origcred;
  213         marshal_new_auth(auth);
  214 
  215         sx_xlock(&auth_unix_lock);
  216         TAILQ_FOREACH(tau, &auth_unix_cache[h], au_link) {
  217                 if (!memcmp(&xcr, &tau->au_xcred, sizeof(xcr))) {
  218                         /*
  219                          * We lost a race to create the AUTH that
  220                          * matches this cred.
  221                          */
  222                         sx_xunlock(&auth_unix_lock);
  223                         AUTH_DESTROY(auth);
  224                         goto again;
  225                 }
  226         }
  227 
  228         auth_unix_count++;
  229         TAILQ_INSERT_TAIL(&auth_unix_cache[h], au, au_link);
  230         TAILQ_INSERT_TAIL(&auth_unix_all, au, au_alllink);
  231         refcount_acquire(&au->au_refs); /* one for the cache, one for user */
  232         sx_xunlock(&auth_unix_lock);
  233 
  234         return (auth);
  235 }
  236 
  237 /*
  238  * authunix operations
  239  */
  240 
  241 /* ARGSUSED */
  242 static void
  243 authunix_nextverf(AUTH *auth)
  244 {
  245         /* no action necessary */
  246 }
  247 
  248 static bool_t
  249 authunix_marshal(AUTH *auth, XDR *xdrs)
  250 {
  251         struct audata *au;
  252 
  253         au = AUTH_PRIVATE(auth);
  254         return (XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos));
  255 }
  256 
  257 static bool_t
  258 authunix_validate(AUTH *auth, struct opaque_auth *verf)
  259 {
  260         struct audata *au;
  261         XDR xdrs;
  262 
  263         if (verf->oa_flavor == AUTH_SHORT) {
  264                 au = AUTH_PRIVATE(auth);
  265                 xdrmem_create(&xdrs, verf->oa_base, verf->oa_length,
  266                     XDR_DECODE);
  267 
  268                 if (au->au_shcred.oa_base != NULL) {
  269                         mem_free(au->au_shcred.oa_base,
  270                             au->au_shcred.oa_length);
  271                         au->au_shcred.oa_base = NULL;
  272                 }
  273                 if (xdr_opaque_auth(&xdrs, &au->au_shcred)) {
  274                         auth->ah_cred = au->au_shcred;
  275                 } else {
  276                         xdrs.x_op = XDR_FREE;
  277                         (void)xdr_opaque_auth(&xdrs, &au->au_shcred);
  278                         au->au_shcred.oa_base = NULL;
  279                         auth->ah_cred = au->au_origcred;
  280                 }
  281                 marshal_new_auth(auth);
  282         }
  283         return (TRUE);
  284 }
  285 
  286 static bool_t
  287 authunix_refresh(AUTH *auth, void *dummy)
  288 {
  289         struct audata *au = AUTH_PRIVATE(auth);
  290         struct xucred xcr;
  291         uint32_t time;
  292         struct timeval now;
  293         XDR xdrs;
  294         int stat;
  295 
  296         if (auth->ah_cred.oa_base == au->au_origcred.oa_base) {
  297                 /* there is no hope.  Punt */
  298                 return (FALSE);
  299         }
  300         au->au_shfaults ++;
  301 
  302         /* first deserialize the creds back into a struct ucred */
  303         xdrmem_create(&xdrs, au->au_origcred.oa_base,
  304             au->au_origcred.oa_length, XDR_DECODE);
  305         stat = xdr_authunix_parms(&xdrs, &time, &xcr);
  306         if (! stat)
  307                 goto done;
  308 
  309         /* update the time and serialize in place */
  310         getmicrotime(&now);
  311         time = now.tv_sec;
  312         xdrs.x_op = XDR_ENCODE;
  313         XDR_SETPOS(&xdrs, 0);
  314 
  315         stat = xdr_authunix_parms(&xdrs, &time, &xcr);
  316         if (! stat)
  317                 goto done;
  318         auth->ah_cred = au->au_origcred;
  319         marshal_new_auth(auth);
  320 done:
  321         XDR_DESTROY(&xdrs);
  322         return (stat);
  323 }
  324 
  325 static void
  326 authunix_destroy(AUTH *auth)
  327 {
  328         struct audata *au;
  329 
  330         au = AUTH_PRIVATE(auth);
  331 
  332         if (!refcount_release(&au->au_refs))
  333                 return;
  334 
  335         mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length);
  336 
  337         if (au->au_shcred.oa_base != NULL)
  338                 mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length);
  339 
  340         mem_free(auth->ah_private, sizeof(struct audata));
  341 
  342         if (auth->ah_verf.oa_base != NULL)
  343                 mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length);
  344 
  345         mem_free(auth, sizeof(*auth));
  346 }
  347 
  348 /*
  349  * Marshals (pre-serializes) an auth struct.
  350  * sets private data, au_marshed and au_mpos
  351  */
  352 static void
  353 marshal_new_auth(AUTH *auth)
  354 {
  355         XDR     xdr_stream;
  356         XDR     *xdrs = &xdr_stream;
  357         struct audata *au;
  358 
  359         au = AUTH_PRIVATE(auth);
  360         xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE);
  361         if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) ||
  362             (! xdr_opaque_auth(xdrs, &(auth->ah_verf))))
  363                 printf("auth_none.c - Fatal marshalling problem");
  364         else
  365                 au->au_mpos = XDR_GETPOS(xdrs);
  366         XDR_DESTROY(xdrs);
  367 }

Cache object: 7c81194501beee4b0134a9d2ed11cfbe


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