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 /* 39 * auth_unix.c, Implements UNIX style authentication parameters. 40 * 41 * Copyright (C) 1984, Sun Microsystems, Inc. 42 * 43 * The system is very weak. The client uses no encryption for it's 44 * credentials and only sends null verifiers. The server sends backs 45 * null verifiers or optionally a verifier that suggests a new short hand 46 * for the credentials. 47 * 48 */ 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/hash.h> 53 #include <sys/kernel.h> 54 #include <sys/lock.h> 55 #include <sys/malloc.h> 56 #include <sys/pcpu.h> 57 #include <sys/refcount.h> 58 #include <sys/sx.h> 59 #include <sys/ucred.h> 60 61 #include <rpc/types.h> 62 #include <rpc/xdr.h> 63 #include <rpc/auth.h> 64 #include <rpc/clnt.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 *, uint32_t, XDR *, struct mbuf *); 71 static bool_t authunix_validate (AUTH *, uint32_t, struct opaque_auth *, 72 struct mbuf **); 73 static bool_t authunix_refresh (AUTH *, void *); 74 static void authunix_destroy (AUTH *); 75 static void marshal_new_auth (AUTH *); 76 77 static const struct auth_ops authunix_ops = { 78 .ah_nextverf = authunix_nextverf, 79 .ah_marshal = authunix_marshal, 80 .ah_validate = authunix_validate, 81 .ah_refresh = authunix_refresh, 82 .ah_destroy = authunix_destroy, 83 }; 84 85 /* 86 * This struct is pointed to by the ah_private field of an auth_handle. 87 */ 88 struct audata { 89 TAILQ_ENTRY(audata) au_link; 90 TAILQ_ENTRY(audata) au_alllink; 91 volatile u_int au_refs; 92 struct xucred au_xcred; 93 struct opaque_auth au_origcred; /* original credentials */ 94 struct opaque_auth au_shcred; /* short hand cred */ 95 u_long au_shfaults; /* short hand cache faults */ 96 char au_marshed[MAX_AUTH_BYTES]; 97 u_int au_mpos; /* xdr pos at end of marshed */ 98 AUTH *au_auth; /* link back to AUTH */ 99 }; 100 TAILQ_HEAD(audata_list, audata); 101 #define AUTH_PRIVATE(auth) ((struct audata *)auth->ah_private) 102 103 #define AUTH_UNIX_HASH_SIZE 16 104 #define AUTH_UNIX_MAX 256 105 static struct audata_list auth_unix_cache[AUTH_UNIX_HASH_SIZE]; 106 static struct audata_list auth_unix_all; 107 static struct sx auth_unix_lock; 108 static int auth_unix_count; 109 110 static void 111 authunix_init(void *dummy) 112 { 113 int i; 114 115 for (i = 0; i < AUTH_UNIX_HASH_SIZE; i++) 116 TAILQ_INIT(&auth_unix_cache[i]); 117 TAILQ_INIT(&auth_unix_all); 118 sx_init(&auth_unix_lock, "auth_unix_lock"); 119 } 120 SYSINIT(authunix_init, SI_SUB_KMEM, SI_ORDER_ANY, authunix_init, NULL); 121 122 /* 123 * Create a unix style authenticator. 124 * Returns an auth handle with the given stuff in it. 125 */ 126 AUTH * 127 authunix_create(struct ucred *cred) 128 { 129 uint32_t h, th; 130 struct xucred xcr; 131 char mymem[MAX_AUTH_BYTES]; 132 XDR xdrs; 133 AUTH *auth; 134 struct audata *au, *tau; 135 struct timeval now; 136 uint32_t time; 137 int len; 138 139 if (auth_unix_count > AUTH_UNIX_MAX) { 140 while (auth_unix_count > AUTH_UNIX_MAX) { 141 sx_xlock(&auth_unix_lock); 142 tau = TAILQ_FIRST(&auth_unix_all); 143 th = HASHSTEP(HASHINIT, tau->au_xcred.cr_uid) 144 % AUTH_UNIX_HASH_SIZE; 145 TAILQ_REMOVE(&auth_unix_cache[th], tau, au_link); 146 TAILQ_REMOVE(&auth_unix_all, tau, au_alllink); 147 auth_unix_count--; 148 sx_xunlock(&auth_unix_lock); 149 AUTH_DESTROY(tau->au_auth); 150 } 151 } 152 153 /* 154 * Hash the uid to see if we already have an AUTH with this cred. 155 */ 156 h = HASHSTEP(HASHINIT, cred->cr_uid) % AUTH_UNIX_HASH_SIZE; 157 cru2x(cred, &xcr); 158 again: 159 sx_slock(&auth_unix_lock); 160 TAILQ_FOREACH(au, &auth_unix_cache[h], au_link) { 161 if (!memcmp(&xcr, &au->au_xcred, sizeof(xcr))) { 162 refcount_acquire(&au->au_refs); 163 if (sx_try_upgrade(&auth_unix_lock)) { 164 /* 165 * Keep auth_unix_all LRU sorted. 166 */ 167 TAILQ_REMOVE(&auth_unix_all, au, au_alllink); 168 TAILQ_INSERT_TAIL(&auth_unix_all, au, 169 au_alllink); 170 sx_xunlock(&auth_unix_lock); 171 } else { 172 sx_sunlock(&auth_unix_lock); 173 } 174 return (au->au_auth); 175 } 176 } 177 178 sx_sunlock(&auth_unix_lock); 179 180 /* 181 * Allocate and set up auth handle 182 */ 183 au = NULL; 184 auth = mem_alloc(sizeof(*auth)); 185 au = mem_alloc(sizeof(*au)); 186 auth->ah_ops = &authunix_ops; 187 auth->ah_private = (caddr_t)au; 188 auth->ah_verf = au->au_shcred = _null_auth; 189 refcount_init(&au->au_refs, 1); 190 au->au_xcred = xcr; 191 au->au_shfaults = 0; 192 au->au_origcred.oa_base = NULL; 193 au->au_auth = auth; 194 195 getmicrotime(&now); 196 time = now.tv_sec; 197 198 /* 199 * Serialize the parameters into origcred 200 */ 201 xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE); 202 cru2x(cred, &xcr); 203 if (! xdr_authunix_parms(&xdrs, &time, &xcr)) 204 panic("authunix_create: failed to encode creds"); 205 au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs); 206 au->au_origcred.oa_flavor = AUTH_UNIX; 207 au->au_origcred.oa_base = mem_alloc((u_int) len); 208 memcpy(au->au_origcred.oa_base, mymem, (size_t)len); 209 210 /* 211 * set auth handle to reflect new cred. 212 */ 213 auth->ah_cred = au->au_origcred; 214 marshal_new_auth(auth); 215 216 sx_xlock(&auth_unix_lock); 217 TAILQ_FOREACH(tau, &auth_unix_cache[h], au_link) { 218 if (!memcmp(&xcr, &tau->au_xcred, sizeof(xcr))) { 219 /* 220 * We lost a race to create the AUTH that 221 * matches this cred. 222 */ 223 sx_xunlock(&auth_unix_lock); 224 AUTH_DESTROY(auth); 225 goto again; 226 } 227 } 228 229 auth_unix_count++; 230 TAILQ_INSERT_TAIL(&auth_unix_cache[h], au, au_link); 231 TAILQ_INSERT_TAIL(&auth_unix_all, au, au_alllink); 232 refcount_acquire(&au->au_refs); /* one for the cache, one for user */ 233 sx_xunlock(&auth_unix_lock); 234 235 return (auth); 236 } 237 238 /* 239 * authunix operations 240 */ 241 242 /* ARGSUSED */ 243 static void 244 authunix_nextverf(AUTH *auth) 245 { 246 /* no action necessary */ 247 } 248 249 static bool_t 250 authunix_marshal(AUTH *auth, uint32_t xid, XDR *xdrs, struct mbuf *args) 251 { 252 struct audata *au; 253 254 au = AUTH_PRIVATE(auth); 255 if (!XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos)) 256 return (FALSE); 257 258 xdrmbuf_append(xdrs, args); 259 260 return (TRUE); 261 } 262 263 static bool_t 264 authunix_validate(AUTH *auth, uint32_t xid, struct opaque_auth *verf, 265 struct mbuf **mrepp) 266 { 267 struct audata *au; 268 XDR txdrs; 269 270 if (!verf) 271 return (TRUE); 272 273 if (verf->oa_flavor == AUTH_SHORT) { 274 au = AUTH_PRIVATE(auth); 275 xdrmem_create(&txdrs, verf->oa_base, verf->oa_length, 276 XDR_DECODE); 277 278 if (au->au_shcred.oa_base != NULL) { 279 mem_free(au->au_shcred.oa_base, 280 au->au_shcred.oa_length); 281 au->au_shcred.oa_base = NULL; 282 } 283 if (xdr_opaque_auth(&txdrs, &au->au_shcred)) { 284 auth->ah_cred = au->au_shcred; 285 } else { 286 txdrs.x_op = XDR_FREE; 287 (void)xdr_opaque_auth(&txdrs, &au->au_shcred); 288 au->au_shcred.oa_base = NULL; 289 auth->ah_cred = au->au_origcred; 290 } 291 marshal_new_auth(auth); 292 } 293 294 return (TRUE); 295 } 296 297 static bool_t 298 authunix_refresh(AUTH *auth, void *dummy) 299 { 300 struct audata *au = AUTH_PRIVATE(auth); 301 struct xucred xcr; 302 uint32_t time; 303 struct timeval now; 304 XDR xdrs; 305 int stat; 306 307 if (auth->ah_cred.oa_base == au->au_origcred.oa_base) { 308 /* there is no hope. Punt */ 309 return (FALSE); 310 } 311 au->au_shfaults ++; 312 313 /* first deserialize the creds back into a struct ucred */ 314 xdrmem_create(&xdrs, au->au_origcred.oa_base, 315 au->au_origcred.oa_length, XDR_DECODE); 316 stat = xdr_authunix_parms(&xdrs, &time, &xcr); 317 if (! stat) 318 goto done; 319 320 /* update the time and serialize in place */ 321 getmicrotime(&now); 322 time = now.tv_sec; 323 xdrs.x_op = XDR_ENCODE; 324 XDR_SETPOS(&xdrs, 0); 325 326 stat = xdr_authunix_parms(&xdrs, &time, &xcr); 327 if (! stat) 328 goto done; 329 auth->ah_cred = au->au_origcred; 330 marshal_new_auth(auth); 331 done: 332 XDR_DESTROY(&xdrs); 333 return (stat); 334 } 335 336 static void 337 authunix_destroy(AUTH *auth) 338 { 339 struct audata *au; 340 341 au = AUTH_PRIVATE(auth); 342 343 if (!refcount_release(&au->au_refs)) 344 return; 345 346 mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length); 347 348 if (au->au_shcred.oa_base != NULL) 349 mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length); 350 351 mem_free(auth->ah_private, sizeof(struct audata)); 352 353 if (auth->ah_verf.oa_base != NULL) 354 mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length); 355 356 mem_free(auth, sizeof(*auth)); 357 } 358 359 /* 360 * Marshals (pre-serializes) an auth struct. 361 * sets private data, au_marshed and au_mpos 362 */ 363 static void 364 marshal_new_auth(AUTH *auth) 365 { 366 XDR xdr_stream; 367 XDR *xdrs = &xdr_stream; 368 struct audata *au; 369 370 au = AUTH_PRIVATE(auth); 371 xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE); 372 if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) || 373 (! xdr_opaque_auth(xdrs, &(auth->ah_verf)))) 374 printf("auth_none.c - Fatal marshalling problem"); 375 else 376 au->au_mpos = XDR_GETPOS(xdrs); 377 XDR_DESTROY(xdrs); 378 } 379