1 /* $NetBSD: auth_unix.c,v 1.18 2000/07/06 03:03:30 christos Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-3-Clause 5 * 6 * Copyright (c) 2009, Sun Microsystems, Inc. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions are met: 11 * - Redistributions of source code must retain the above copyright notice, 12 * this list of conditions and the following disclaimer. 13 * - Redistributions in binary form must reproduce the above copyright notice, 14 * this list of conditions and the following disclaimer in the documentation 15 * and/or other materials provided with the distribution. 16 * - Neither the name of Sun Microsystems, 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 "AS IS" 21 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char *sccsid2 = "@(#)auth_unix.c 1.19 87/08/11 Copyr 1984 Sun Micro"; 35 static char *sccsid = "@(#)auth_unix.c 2.2 88/08/01 4.0 RPCSRC"; 36 #endif 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 /* 41 * auth_unix.c, Implements UNIX style authentication parameters. 42 * 43 * Copyright (C) 1984, Sun Microsystems, Inc. 44 * 45 * The system is very weak. The client uses no encryption for it's 46 * credentials and only sends null verifiers. The server sends backs 47 * null verifiers or optionally a verifier that suggests a new short hand 48 * for the credentials. 49 * 50 */ 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/hash.h> 55 #include <sys/kernel.h> 56 #include <sys/lock.h> 57 #include <sys/malloc.h> 58 #include <sys/pcpu.h> 59 #include <sys/refcount.h> 60 #include <sys/sx.h> 61 #include <sys/ucred.h> 62 63 #include <rpc/types.h> 64 #include <rpc/xdr.h> 65 #include <rpc/auth.h> 66 #include <rpc/clnt.h> 67 68 #include <rpc/rpc_com.h> 69 70 /* auth_unix.c */ 71 static void authunix_nextverf (AUTH *); 72 static bool_t authunix_marshal (AUTH *, uint32_t, XDR *, struct mbuf *); 73 static bool_t authunix_validate (AUTH *, uint32_t, struct opaque_auth *, 74 struct mbuf **); 75 static bool_t authunix_refresh (AUTH *, void *); 76 static void authunix_destroy (AUTH *); 77 static void marshal_new_auth (AUTH *); 78 79 static const struct auth_ops authunix_ops = { 80 .ah_nextverf = authunix_nextverf, 81 .ah_marshal = authunix_marshal, 82 .ah_validate = authunix_validate, 83 .ah_refresh = authunix_refresh, 84 .ah_destroy = authunix_destroy, 85 }; 86 87 /* 88 * This struct is pointed to by the ah_private field of an auth_handle. 89 */ 90 struct audata { 91 TAILQ_ENTRY(audata) au_link; 92 TAILQ_ENTRY(audata) au_alllink; 93 volatile u_int au_refs; 94 struct xucred au_xcred; 95 struct opaque_auth au_origcred; /* original credentials */ 96 struct opaque_auth au_shcred; /* short hand cred */ 97 u_long au_shfaults; /* short hand cache faults */ 98 char au_marshed[MAX_AUTH_BYTES]; 99 u_int au_mpos; /* xdr pos at end of marshed */ 100 AUTH *au_auth; /* link back to AUTH */ 101 }; 102 TAILQ_HEAD(audata_list, audata); 103 #define AUTH_PRIVATE(auth) ((struct audata *)auth->ah_private) 104 105 #define AUTH_UNIX_HASH_SIZE 16 106 #define AUTH_UNIX_MAX 256 107 static struct audata_list auth_unix_cache[AUTH_UNIX_HASH_SIZE]; 108 static struct audata_list auth_unix_all; 109 static struct sx auth_unix_lock; 110 static int auth_unix_count; 111 112 static void 113 authunix_init(void *dummy) 114 { 115 int i; 116 117 for (i = 0; i < AUTH_UNIX_HASH_SIZE; i++) 118 TAILQ_INIT(&auth_unix_cache[i]); 119 TAILQ_INIT(&auth_unix_all); 120 sx_init(&auth_unix_lock, "auth_unix_lock"); 121 } 122 SYSINIT(authunix_init, SI_SUB_KMEM, SI_ORDER_ANY, authunix_init, NULL); 123 124 /* 125 * Create a unix style authenticator. 126 * Returns an auth handle with the given stuff in it. 127 */ 128 AUTH * 129 authunix_create(struct ucred *cred) 130 { 131 uint32_t h, th; 132 struct xucred xcr; 133 char mymem[MAX_AUTH_BYTES]; 134 XDR xdrs; 135 AUTH *auth; 136 struct audata *au, *tau; 137 struct timeval now; 138 uint32_t time; 139 int len; 140 141 if (auth_unix_count > AUTH_UNIX_MAX) { 142 while (auth_unix_count > AUTH_UNIX_MAX) { 143 sx_xlock(&auth_unix_lock); 144 tau = TAILQ_FIRST(&auth_unix_all); 145 th = HASHSTEP(HASHINIT, tau->au_xcred.cr_uid) 146 % AUTH_UNIX_HASH_SIZE; 147 TAILQ_REMOVE(&auth_unix_cache[th], tau, au_link); 148 TAILQ_REMOVE(&auth_unix_all, tau, au_alllink); 149 auth_unix_count--; 150 sx_xunlock(&auth_unix_lock); 151 AUTH_DESTROY(tau->au_auth); 152 } 153 } 154 155 /* 156 * Hash the uid to see if we already have an AUTH with this cred. 157 */ 158 h = HASHSTEP(HASHINIT, cred->cr_uid) % AUTH_UNIX_HASH_SIZE; 159 cru2x(cred, &xcr); 160 again: 161 sx_slock(&auth_unix_lock); 162 TAILQ_FOREACH(au, &auth_unix_cache[h], au_link) { 163 if (!memcmp(&xcr, &au->au_xcred, sizeof(xcr))) { 164 refcount_acquire(&au->au_refs); 165 if (sx_try_upgrade(&auth_unix_lock)) { 166 /* 167 * Keep auth_unix_all LRU sorted. 168 */ 169 TAILQ_REMOVE(&auth_unix_all, au, au_alllink); 170 TAILQ_INSERT_TAIL(&auth_unix_all, au, 171 au_alllink); 172 sx_xunlock(&auth_unix_lock); 173 } else { 174 sx_sunlock(&auth_unix_lock); 175 } 176 return (au->au_auth); 177 } 178 } 179 180 sx_sunlock(&auth_unix_lock); 181 182 /* 183 * Allocate and set up auth handle 184 */ 185 au = NULL; 186 auth = mem_alloc(sizeof(*auth)); 187 au = mem_alloc(sizeof(*au)); 188 auth->ah_ops = &authunix_ops; 189 auth->ah_private = (caddr_t)au; 190 auth->ah_verf = au->au_shcred = _null_auth; 191 refcount_init(&au->au_refs, 1); 192 au->au_xcred = xcr; 193 au->au_shfaults = 0; 194 au->au_origcred.oa_base = NULL; 195 au->au_auth = auth; 196 197 getmicrotime(&now); 198 time = now.tv_sec; 199 200 /* 201 * Serialize the parameters into origcred 202 */ 203 xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE); 204 cru2x(cred, &xcr); 205 if (! xdr_authunix_parms(&xdrs, &time, &xcr)) 206 panic("authunix_create: failed to encode creds"); 207 au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs); 208 au->au_origcred.oa_flavor = AUTH_UNIX; 209 au->au_origcred.oa_base = mem_alloc((u_int) len); 210 memcpy(au->au_origcred.oa_base, mymem, (size_t)len); 211 212 /* 213 * set auth handle to reflect new cred. 214 */ 215 auth->ah_cred = au->au_origcred; 216 marshal_new_auth(auth); 217 218 sx_xlock(&auth_unix_lock); 219 TAILQ_FOREACH(tau, &auth_unix_cache[h], au_link) { 220 if (!memcmp(&xcr, &tau->au_xcred, sizeof(xcr))) { 221 /* 222 * We lost a race to create the AUTH that 223 * matches this cred. 224 */ 225 sx_xunlock(&auth_unix_lock); 226 AUTH_DESTROY(auth); 227 goto again; 228 } 229 } 230 231 auth_unix_count++; 232 TAILQ_INSERT_TAIL(&auth_unix_cache[h], au, au_link); 233 TAILQ_INSERT_TAIL(&auth_unix_all, au, au_alllink); 234 refcount_acquire(&au->au_refs); /* one for the cache, one for user */ 235 sx_xunlock(&auth_unix_lock); 236 237 return (auth); 238 } 239 240 /* 241 * authunix operations 242 */ 243 244 /* ARGSUSED */ 245 static void 246 authunix_nextverf(AUTH *auth) 247 { 248 /* no action necessary */ 249 } 250 251 static bool_t 252 authunix_marshal(AUTH *auth, uint32_t xid, XDR *xdrs, struct mbuf *args) 253 { 254 struct audata *au; 255 256 au = AUTH_PRIVATE(auth); 257 if (!XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos)) 258 return (FALSE); 259 260 xdrmbuf_append(xdrs, args); 261 262 return (TRUE); 263 } 264 265 static bool_t 266 authunix_validate(AUTH *auth, uint32_t xid, struct opaque_auth *verf, 267 struct mbuf **mrepp) 268 { 269 struct audata *au; 270 XDR txdrs; 271 272 if (!verf) 273 return (TRUE); 274 275 if (verf->oa_flavor == AUTH_SHORT) { 276 au = AUTH_PRIVATE(auth); 277 xdrmem_create(&txdrs, verf->oa_base, verf->oa_length, 278 XDR_DECODE); 279 280 if (au->au_shcred.oa_base != NULL) { 281 mem_free(au->au_shcred.oa_base, 282 au->au_shcred.oa_length); 283 au->au_shcred.oa_base = NULL; 284 } 285 if (xdr_opaque_auth(&txdrs, &au->au_shcred)) { 286 auth->ah_cred = au->au_shcred; 287 } else { 288 txdrs.x_op = XDR_FREE; 289 (void)xdr_opaque_auth(&txdrs, &au->au_shcred); 290 au->au_shcred.oa_base = NULL; 291 auth->ah_cred = au->au_origcred; 292 } 293 marshal_new_auth(auth); 294 } 295 296 return (TRUE); 297 } 298 299 static bool_t 300 authunix_refresh(AUTH *auth, void *dummy) 301 { 302 struct audata *au = AUTH_PRIVATE(auth); 303 struct xucred xcr; 304 uint32_t time; 305 struct timeval now; 306 XDR xdrs; 307 int stat; 308 309 if (auth->ah_cred.oa_base == au->au_origcred.oa_base) { 310 /* there is no hope. Punt */ 311 return (FALSE); 312 } 313 au->au_shfaults ++; 314 315 /* first deserialize the creds back into a struct ucred */ 316 xdrmem_create(&xdrs, au->au_origcred.oa_base, 317 au->au_origcred.oa_length, XDR_DECODE); 318 stat = xdr_authunix_parms(&xdrs, &time, &xcr); 319 if (! stat) 320 goto done; 321 322 /* update the time and serialize in place */ 323 getmicrotime(&now); 324 time = now.tv_sec; 325 xdrs.x_op = XDR_ENCODE; 326 XDR_SETPOS(&xdrs, 0); 327 328 stat = xdr_authunix_parms(&xdrs, &time, &xcr); 329 if (! stat) 330 goto done; 331 auth->ah_cred = au->au_origcred; 332 marshal_new_auth(auth); 333 done: 334 XDR_DESTROY(&xdrs); 335 return (stat); 336 } 337 338 static void 339 authunix_destroy(AUTH *auth) 340 { 341 struct audata *au; 342 343 au = AUTH_PRIVATE(auth); 344 345 if (!refcount_release(&au->au_refs)) 346 return; 347 348 mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length); 349 350 if (au->au_shcred.oa_base != NULL) 351 mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length); 352 353 mem_free(auth->ah_private, sizeof(struct audata)); 354 355 if (auth->ah_verf.oa_base != NULL) 356 mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length); 357 358 mem_free(auth, sizeof(*auth)); 359 } 360 361 /* 362 * Marshals (pre-serializes) an auth struct. 363 * sets private data, au_marshed and au_mpos 364 */ 365 static void 366 marshal_new_auth(AUTH *auth) 367 { 368 XDR xdr_stream; 369 XDR *xdrs = &xdr_stream; 370 struct audata *au; 371 372 au = AUTH_PRIVATE(auth); 373 xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE); 374 if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) || 375 (! xdr_opaque_auth(xdrs, &(auth->ah_verf)))) 376 printf("auth_none.c - Fatal marshalling problem"); 377 else 378 au->au_mpos = XDR_GETPOS(xdrs); 379 XDR_DESTROY(xdrs); 380 } 381