1 /* $OpenBSD: auth_unix.c,v 1.22 2010/09/01 14:43:34 millert 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 /* 35 * auth_unix.c, Implements UNIX style authentication parameters. 36 * 37 * The system is very weak. The client uses no encryption for it's 38 * credentials and only sends null verifiers. The server sends backs 39 * null verifiers or optionally a verifier that suggests a new short hand 40 * for the credentials. 41 * 42 */ 43 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <unistd.h> 47 #include <string.h> 48 49 #include <rpc/types.h> 50 #include <rpc/xdr.h> 51 #include <rpc/rpc.h> 52 #include <rpc/auth.h> 53 #include <rpc/auth_unix.h> 54 55 /* 56 * Unix authenticator operations vector 57 */ 58 static void authunix_nextverf(struct __rpc_auth *); 59 static bool_t authunix_marshal(struct __rpc_auth *, XDR *); 60 static bool_t authunix_validate(struct __rpc_auth *, struct opaque_auth *); 61 static bool_t authunix_refresh(struct __rpc_auth *); 62 static void authunix_destroy(struct __rpc_auth *); 63 64 static struct auth_ops auth_unix_ops = { 65 authunix_nextverf, 66 authunix_marshal, 67 authunix_validate, 68 authunix_refresh, 69 authunix_destroy 70 }; 71 72 /* 73 * This struct is pointed to by the ah_private field of an auth_handle. 74 */ 75 struct audata { 76 struct opaque_auth au_origcred; /* original credentials */ 77 struct opaque_auth au_shcred; /* short hand cred */ 78 u_long au_shfaults; /* short hand cache faults */ 79 char au_marshed[MAX_AUTH_BYTES]; 80 u_int au_mpos; /* xdr pos at end of marshed */ 81 }; 82 #define AUTH_PRIVATE(auth) ((struct audata *)auth->ah_private) 83 84 static void marshal_new_auth(AUTH *auth); 85 86 87 /* 88 * Create a unix style authenticator. 89 * Returns an auth handle with the given stuff in it. 90 */ 91 AUTH * 92 authunix_create(char *machname, int uid, int gid, int len, int *aup_gids) 93 { 94 struct authunix_parms aup; 95 char mymem[MAX_AUTH_BYTES]; 96 struct timeval now; 97 XDR xdrs; 98 AUTH *auth; 99 struct audata *au; 100 101 /* 102 * Allocate and set up auth handle 103 */ 104 auth = (AUTH *)mem_alloc(sizeof(*auth)); 105 #ifndef KERNEL 106 if (auth == NULL) { 107 (void)fprintf(stderr, "authunix_create: out of memory\n"); 108 return (NULL); 109 } 110 #endif 111 au = (struct audata *)mem_alloc(sizeof(*au)); 112 #ifndef KERNEL 113 if (au == NULL) { 114 (void)fprintf(stderr, "authunix_create: out of memory\n"); 115 free(auth); 116 return (NULL); 117 } 118 #endif 119 auth->ah_ops = &auth_unix_ops; 120 auth->ah_private = (caddr_t)au; 121 auth->ah_verf = au->au_shcred = _null_auth; 122 au->au_shfaults = 0; 123 124 /* 125 * fill in param struct from the given params 126 */ 127 (void)gettimeofday(&now, NULL); 128 aup.aup_time = now.tv_sec; 129 aup.aup_machname = machname; 130 aup.aup_uid = uid; 131 aup.aup_gid = gid; 132 aup.aup_len = (u_int)len; 133 aup.aup_gids = aup_gids; 134 135 /* 136 * Serialize the parameters into origcred 137 */ 138 xdrmem_create(&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE); 139 if (!xdr_authunix_parms(&xdrs, &aup)) 140 goto authfail; 141 au->au_origcred.oa_length = len = XDR_GETPOS(&xdrs); 142 au->au_origcred.oa_flavor = AUTH_UNIX; 143 #ifdef KERNEL 144 au->au_origcred.oa_base = mem_alloc((u_int) len); 145 #else 146 if ((au->au_origcred.oa_base = mem_alloc((u_int) len)) == NULL) { 147 (void)fprintf(stderr, "authunix_create: out of memory\n"); 148 goto authfail; 149 } 150 #endif 151 memcpy(au->au_origcred.oa_base, mymem, (u_int)len); 152 153 /* 154 * set auth handle to reflect new cred. 155 */ 156 auth->ah_cred = au->au_origcred; 157 marshal_new_auth(auth); 158 return (auth); 159 160 authfail: 161 XDR_DESTROY(&xdrs); 162 free(au); 163 free(auth); 164 return (NULL); 165 } 166 167 168 /* 169 * Some servers will refuse mounts if the group list is larger 170 * than it expects (like 8). This allows the application to set 171 * the maximum size of the group list that will be sent. 172 */ 173 static int maxgrplist = NGRPS; 174 175 void 176 set_rpc_maxgrouplist(int num) 177 { 178 if (num < NGRPS) 179 maxgrplist = num; 180 } 181 182 /* 183 * Returns an auth handle with parameters determined by doing lots of 184 * syscalls. 185 */ 186 AUTH * 187 authunix_create_default(void) 188 { 189 int len, i; 190 char machname[MAX_MACHINE_NAME + 1]; 191 uid_t uid; 192 gid_t gid; 193 gid_t gids[NGRPS]; 194 int gids2[NGRPS]; 195 196 if (gethostname(machname, sizeof machname) == -1) 197 return (NULL); 198 machname[MAX_MACHINE_NAME] = 0; 199 uid = geteuid(); 200 gid = getegid(); 201 if ((len = getgroups(NGRPS, gids)) < 0) 202 return (NULL); 203 if (len > maxgrplist) 204 len = maxgrplist; 205 for (i = 0; i < len; i++) 206 gids2[i] = gids[i]; 207 return (authunix_create(machname, uid, gid, len, gids2)); 208 } 209 210 /* 211 * authunix operations 212 */ 213 /* ARGSUSED */ 214 static void 215 authunix_nextverf(AUTH *auth) 216 { 217 /* no action necessary */ 218 } 219 220 static bool_t 221 authunix_marshal(AUTH *auth, XDR *xdrs) 222 { 223 struct audata *au = AUTH_PRIVATE(auth); 224 225 return (XDR_PUTBYTES(xdrs, au->au_marshed, au->au_mpos)); 226 } 227 228 static bool_t 229 authunix_validate(AUTH *auth, struct opaque_auth *verf) 230 { 231 struct audata *au; 232 XDR xdrs; 233 234 if (verf->oa_flavor == AUTH_SHORT) { 235 au = AUTH_PRIVATE(auth); 236 xdrmem_create(&xdrs, verf->oa_base, verf->oa_length, XDR_DECODE); 237 238 if (au->au_shcred.oa_base != NULL) { 239 mem_free(au->au_shcred.oa_base, 240 au->au_shcred.oa_length); 241 au->au_shcred.oa_base = NULL; 242 } 243 if (xdr_opaque_auth(&xdrs, &au->au_shcred)) { 244 auth->ah_cred = au->au_shcred; 245 } else { 246 xdrs.x_op = XDR_FREE; 247 (void)xdr_opaque_auth(&xdrs, &au->au_shcred); 248 au->au_shcred.oa_base = NULL; 249 auth->ah_cred = au->au_origcred; 250 } 251 marshal_new_auth(auth); 252 } 253 return (TRUE); 254 } 255 256 static bool_t 257 authunix_refresh(AUTH *auth) 258 { 259 struct audata *au = AUTH_PRIVATE(auth); 260 struct authunix_parms aup; 261 struct timeval now; 262 XDR xdrs; 263 int stat; 264 265 if (auth->ah_cred.oa_base == au->au_origcred.oa_base) { 266 /* there is no hope. Punt */ 267 return (FALSE); 268 } 269 au->au_shfaults ++; 270 271 /* first deserialize the creds back into a struct authunix_parms */ 272 aup.aup_machname = NULL; 273 aup.aup_gids = NULL; 274 xdrmem_create(&xdrs, au->au_origcred.oa_base, 275 au->au_origcred.oa_length, XDR_DECODE); 276 stat = xdr_authunix_parms(&xdrs, &aup); 277 if (! stat) 278 goto done; 279 280 /* update the time and serialize in place */ 281 (void)gettimeofday(&now, NULL); 282 aup.aup_time = now.tv_sec; 283 xdrs.x_op = XDR_ENCODE; 284 XDR_SETPOS(&xdrs, 0); 285 stat = xdr_authunix_parms(&xdrs, &aup); 286 if (! stat) 287 goto done; 288 auth->ah_cred = au->au_origcred; 289 marshal_new_auth(auth); 290 done: 291 /* free the struct authunix_parms created by deserializing */ 292 xdrs.x_op = XDR_FREE; 293 (void)xdr_authunix_parms(&xdrs, &aup); 294 XDR_DESTROY(&xdrs); 295 return (stat); 296 } 297 298 static void 299 authunix_destroy(AUTH *auth) 300 { 301 struct audata *au = AUTH_PRIVATE(auth); 302 303 mem_free(au->au_origcred.oa_base, au->au_origcred.oa_length); 304 305 if (au->au_shcred.oa_base != NULL) 306 mem_free(au->au_shcred.oa_base, au->au_shcred.oa_length); 307 308 mem_free(auth->ah_private, sizeof(struct audata)); 309 310 if (auth->ah_verf.oa_base != NULL) 311 mem_free(auth->ah_verf.oa_base, auth->ah_verf.oa_length); 312 313 mem_free((caddr_t)auth, sizeof(*auth)); 314 } 315 316 /* 317 * Marshals (pre-serializes) an auth struct. 318 * sets private data, au_marshed and au_mpos 319 */ 320 static void 321 marshal_new_auth(AUTH *auth) 322 { 323 XDR xdr_stream; 324 XDR *xdrs = &xdr_stream; 325 struct audata *au = AUTH_PRIVATE(auth); 326 327 xdrmem_create(xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE); 328 if ((! xdr_opaque_auth(xdrs, &(auth->ah_cred))) || 329 (! xdr_opaque_auth(xdrs, &(auth->ah_verf)))) { 330 perror("auth_none.c - Fatal marshalling problem"); 331 } else { 332 au->au_mpos = XDR_GETPOS(xdrs); 333 } 334 XDR_DESTROY(xdrs); 335 } 336