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 #include <sys/cdefs.h> 34 /* 35 * auth_unix.c, Implements UNIX style authentication parameters. 36 * 37 * Copyright (C) 1984, Sun Microsystems, Inc. 38 * 39 * The system is very weak. The client uses no encryption for it's 40 * credentials and only sends null verifiers. The server sends backs 41 * null verifiers or optionally a verifier that suggests a new short hand 42 * for the credentials. 43 * 44 */ 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/hash.h> 49 #include <sys/kernel.h> 50 #include <sys/lock.h> 51 #include <sys/malloc.h> 52 #include <sys/pcpu.h> 53 #include <sys/refcount.h> 54 #include <sys/sx.h> 55 #include <sys/ucred.h> 56 57 #include <rpc/types.h> 58 #include <rpc/xdr.h> 59 #include <rpc/auth.h> 60 #include <rpc/clnt.h> 61 62 #include <rpc/rpc_com.h> 63 64 /* auth_unix.c */ 65 static void authunix_nextverf (AUTH *); 66 static bool_t authunix_marshal (AUTH *, uint32_t, XDR *, struct mbuf *); 67 static bool_t authunix_validate (AUTH *, uint32_t, struct opaque_auth *, 68 struct mbuf **); 69 static bool_t authunix_refresh (AUTH *, void *); 70 static void authunix_destroy (AUTH *); 71 static void marshal_new_auth (AUTH *); 72 73 static const struct auth_ops authunix_ops = { 74 .ah_nextverf = authunix_nextverf, 75 .ah_marshal = authunix_marshal, 76 .ah_validate = authunix_validate, 77 .ah_refresh = authunix_refresh, 78 .ah_destroy = authunix_destroy, 79 }; 80 81 /* 82 * This struct is pointed to by the ah_private field of an auth_handle. 83 */ 84 struct audata { 85 TAILQ_ENTRY(audata) au_link; 86 TAILQ_ENTRY(audata) au_alllink; 87 volatile u_int au_refs; 88 struct xucred au_xcred; 89 struct opaque_auth au_origcred; /* original credentials */ 90 struct opaque_auth au_shcred; /* short hand cred */ 91 u_long au_shfaults; /* short hand cache faults */ 92 char au_marshed[MAX_AUTH_BYTES]; 93 u_int au_mpos; /* xdr pos at end of marshed */ 94 AUTH *au_auth; /* link back to AUTH */ 95 }; 96 TAILQ_HEAD(audata_list, audata); 97 #define AUTH_PRIVATE(auth) ((struct audata *)auth->ah_private) 98 99 #define AUTH_UNIX_HASH_SIZE 16 100 #define AUTH_UNIX_MAX 256 101 static struct audata_list auth_unix_cache[AUTH_UNIX_HASH_SIZE]; 102 static struct audata_list auth_unix_all; 103 static struct sx auth_unix_lock; 104 static int auth_unix_count; 105 106 static void 107 authunix_init(void *dummy) 108 { 109 int i; 110 111 for (i = 0; i < AUTH_UNIX_HASH_SIZE; i++) 112 TAILQ_INIT(&auth_unix_cache[i]); 113 TAILQ_INIT(&auth_unix_all); 114 sx_init(&auth_unix_lock, "auth_unix_lock"); 115 } 116 SYSINIT(authunix_init, SI_SUB_KMEM, SI_ORDER_ANY, authunix_init, NULL); 117 118 /* 119 * Create a unix style authenticator. 120 * Returns an auth handle with the given stuff in it. 121 */ 122 AUTH * 123 authunix_create(struct ucred *cred) 124 { 125 uint32_t h, th; 126 struct xucred xcr; 127 char mymem[MAX_AUTH_BYTES]; 128 XDR xdrs; 129 AUTH *auth; 130 struct audata *au, *tau; 131 struct timeval now; 132 uint32_t time; 133 int len; 134 135 if (auth_unix_count > AUTH_UNIX_MAX) { 136 while (auth_unix_count > AUTH_UNIX_MAX) { 137 sx_xlock(&auth_unix_lock); 138 tau = TAILQ_FIRST(&auth_unix_all); 139 th = HASHSTEP(HASHINIT, tau->au_xcred.cr_uid) 140 % AUTH_UNIX_HASH_SIZE; 141 TAILQ_REMOVE(&auth_unix_cache[th], tau, au_link); 142 TAILQ_REMOVE(&auth_unix_all, tau, au_alllink); 143 auth_unix_count--; 144 sx_xunlock(&auth_unix_lock); 145 AUTH_DESTROY(tau->au_auth); 146 } 147 } 148 149 /* 150 * Hash the uid to see if we already have an AUTH with this cred. 151 */ 152 h = HASHSTEP(HASHINIT, cred->cr_uid) % AUTH_UNIX_HASH_SIZE; 153 cru2x(cred, &xcr); 154 again: 155 sx_slock(&auth_unix_lock); 156 TAILQ_FOREACH(au, &auth_unix_cache[h], au_link) { 157 if (!memcmp(&xcr, &au->au_xcred, sizeof(xcr))) { 158 refcount_acquire(&au->au_refs); 159 if (sx_try_upgrade(&auth_unix_lock)) { 160 /* 161 * Keep auth_unix_all LRU sorted. 162 */ 163 TAILQ_REMOVE(&auth_unix_all, au, au_alllink); 164 TAILQ_INSERT_TAIL(&auth_unix_all, au, 165 au_alllink); 166 sx_xunlock(&auth_unix_lock); 167 } else { 168 sx_sunlock(&auth_unix_lock); 169 } 170 return (au->au_auth); 171 } 172 } 173 174 sx_sunlock(&auth_unix_lock); 175 176 /* 177 * Allocate and set up auth handle 178 */ 179 au = NULL; 180 auth = mem_alloc(sizeof(*auth)); 181 au = mem_alloc(sizeof(*au)); 182 auth->ah_ops = &authunix_ops; 183 auth->ah_private = (caddr_t)au; 184 auth->ah_verf = au->au_shcred = _null_auth; 185 refcount_init(&au->au_refs, 1); 186 au->au_xcred = xcr; 187 au->au_shfaults = 0; 188 au->au_origcred.oa_base = NULL; 189 au->au_auth = auth; 190 191 getmicrotime(&now); 192 time = now.tv_sec; 193 194 /* 195 * Serialize the parameters into origcred 196 */ 197 xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE); 198 cru2x(cred, &xcr); 199 if (! xdr_authunix_parms(&xdrs, &time, &xcr)) 200 panic("authunix_create: failed to encode creds"); 201 au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs); 202 au->au_origcred.oa_flavor = AUTH_UNIX; 203 au->au_origcred.oa_base = mem_alloc((u_int) len); 204 memcpy(au->au_origcred.oa_base, mymem, (size_t)len); 205 206 /* 207 * set auth handle to reflect new cred. 208 */ 209 auth->ah_cred = au->au_origcred; 210 marshal_new_auth(auth); 211 212 sx_xlock(&auth_unix_lock); 213 TAILQ_FOREACH(tau, &auth_unix_cache[h], au_link) { 214 if (!memcmp(&xcr, &tau->au_xcred, sizeof(xcr))) { 215 /* 216 * We lost a race to create the AUTH that 217 * matches this cred. 218 */ 219 sx_xunlock(&auth_unix_lock); 220 AUTH_DESTROY(auth); 221 goto again; 222 } 223 } 224 225 auth_unix_count++; 226 TAILQ_INSERT_TAIL(&auth_unix_cache[h], au, au_link); 227 TAILQ_INSERT_TAIL(&auth_unix_all, au, au_alllink); 228 refcount_acquire(&au->au_refs); /* one for the cache, one for user */ 229 sx_xunlock(&auth_unix_lock); 230 231 return (auth); 232 } 233 234 /* 235 * authunix operations 236 */ 237 238 /* ARGSUSED */ 239 static void 240 authunix_nextverf(AUTH *auth) 241 { 242 /* no action necessary */ 243 } 244 245 static bool_t 246 authunix_marshal(AUTH *auth, uint32_t xid, XDR *xdrs, struct mbuf *args) 247 { 248 struct audata *au; 249 250 au = AUTH_PRIVATE(auth); 251 if (!XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos)) 252 return (FALSE); 253 254 xdrmbuf_append(xdrs, args); 255 256 return (TRUE); 257 } 258 259 static bool_t 260 authunix_validate(AUTH *auth, uint32_t xid, struct opaque_auth *verf, 261 struct mbuf **mrepp) 262 { 263 struct audata *au; 264 XDR txdrs; 265 266 if (!verf) 267 return (TRUE); 268 269 if (verf->oa_flavor == AUTH_SHORT) { 270 au = AUTH_PRIVATE(auth); 271 xdrmem_create(&txdrs, verf->oa_base, verf->oa_length, 272 XDR_DECODE); 273 274 if (au->au_shcred.oa_base != NULL) { 275 mem_free(au->au_shcred.oa_base, 276 au->au_shcred.oa_length); 277 au->au_shcred.oa_base = NULL; 278 } 279 if (xdr_opaque_auth(&txdrs, &au->au_shcred)) { 280 auth->ah_cred = au->au_shcred; 281 } else { 282 txdrs.x_op = XDR_FREE; 283 (void)xdr_opaque_auth(&txdrs, &au->au_shcred); 284 au->au_shcred.oa_base = NULL; 285 auth->ah_cred = au->au_origcred; 286 } 287 marshal_new_auth(auth); 288 } 289 290 return (TRUE); 291 } 292 293 static bool_t 294 authunix_refresh(AUTH *auth, void *dummy) 295 { 296 struct audata *au = AUTH_PRIVATE(auth); 297 struct xucred xcr; 298 uint32_t time; 299 struct timeval now; 300 XDR xdrs; 301 int stat; 302 303 if (auth->ah_cred.oa_base == au->au_origcred.oa_base) { 304 /* there is no hope. Punt */ 305 return (FALSE); 306 } 307 au->au_shfaults ++; 308 309 /* first deserialize the creds back into a struct ucred */ 310 xdrmem_create(&xdrs, au->au_origcred.oa_base, 311 au->au_origcred.oa_length, XDR_DECODE); 312 stat = xdr_authunix_parms(&xdrs, &time, &xcr); 313 if (! stat) 314 goto done; 315 316 /* update the time and serialize in place */ 317 getmicrotime(&now); 318 time = now.tv_sec; 319 xdrs.x_op = XDR_ENCODE; 320 XDR_SETPOS(&xdrs, 0); 321 322 stat = xdr_authunix_parms(&xdrs, &time, &xcr); 323 if (! stat) 324 goto done; 325 auth->ah_cred = au->au_origcred; 326 marshal_new_auth(auth); 327 done: 328 XDR_DESTROY(&xdrs); 329 return (stat); 330 } 331 332 static void 333 authunix_destroy(AUTH *auth) 334 { 335 struct audata *au; 336 337 au = AUTH_PRIVATE(auth); 338 339 if (!refcount_release(&au->au_refs)) 340 return; 341 342 mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length); 343 344 if (au->au_shcred.oa_base != NULL) 345 mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length); 346 347 mem_free(auth->ah_private, sizeof(struct audata)); 348 349 if (auth->ah_verf.oa_base != NULL) 350 mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length); 351 352 mem_free(auth, sizeof(*auth)); 353 } 354 355 /* 356 * Marshals (pre-serializes) an auth struct. 357 * sets private data, au_marshed and au_mpos 358 */ 359 static void 360 marshal_new_auth(AUTH *auth) 361 { 362 XDR xdr_stream; 363 XDR *xdrs = &xdr_stream; 364 struct audata *au; 365 366 au = AUTH_PRIVATE(auth); 367 xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE); 368 if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) || 369 (! xdr_opaque_auth(xdrs, &(auth->ah_verf)))) 370 printf("auth_none.c - Fatal marshalling problem"); 371 else 372 au->au_mpos = XDR_GETPOS(xdrs); 373 XDR_DESTROY(xdrs); 374 } 375