1 /* 2 * linux/fs/nfs/nfs4namespace.c 3 * 4 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> 5 * - Modified by David Howells <dhowells@redhat.com> 6 * 7 * NFSv4 namespace 8 */ 9 10 #include <linux/dcache.h> 11 #include <linux/mount.h> 12 #include <linux/namei.h> 13 #include <linux/nfs_fs.h> 14 #include <linux/nfs_mount.h> 15 #include <linux/slab.h> 16 #include <linux/string.h> 17 #include <linux/sunrpc/clnt.h> 18 #include <linux/sunrpc/addr.h> 19 #include <linux/vfs.h> 20 #include <linux/inet.h> 21 #include "internal.h" 22 #include "nfs4_fs.h" 23 #include "dns_resolve.h" 24 25 #define NFSDBG_FACILITY NFSDBG_VFS 26 27 /* 28 * Convert the NFSv4 pathname components into a standard posix path. 29 * 30 * Note that the resulting string will be placed at the end of the buffer 31 */ 32 static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname, 33 char *buffer, ssize_t buflen) 34 { 35 char *end = buffer + buflen; 36 int n; 37 38 *--end = '\0'; 39 buflen--; 40 41 n = pathname->ncomponents; 42 while (--n >= 0) { 43 const struct nfs4_string *component = &pathname->components[n]; 44 buflen -= component->len + 1; 45 if (buflen < 0) 46 goto Elong; 47 end -= component->len; 48 memcpy(end, component->data, component->len); 49 *--end = '/'; 50 } 51 return end; 52 Elong: 53 return ERR_PTR(-ENAMETOOLONG); 54 } 55 56 /* 57 * return the path component of "<server>:<path>" 58 * nfspath - the "<server>:<path>" string 59 * end - one past the last char that could contain "<server>:" 60 * returns NULL on failure 61 */ 62 static char *nfs_path_component(const char *nfspath, const char *end) 63 { 64 char *p; 65 66 if (*nfspath == '[') { 67 /* parse [] escaped IPv6 addrs */ 68 p = strchr(nfspath, ']'); 69 if (p != NULL && ++p < end && *p == ':') 70 return p + 1; 71 } else { 72 /* otherwise split on first colon */ 73 p = strchr(nfspath, ':'); 74 if (p != NULL && p < end) 75 return p + 1; 76 } 77 return NULL; 78 } 79 80 /* 81 * Determine the mount path as a string 82 */ 83 static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen) 84 { 85 char *limit; 86 char *path = nfs_path(&limit, dentry, buffer, buflen, 87 NFS_PATH_CANONICAL); 88 if (!IS_ERR(path)) { 89 char *path_component = nfs_path_component(path, limit); 90 if (path_component) 91 return path_component; 92 } 93 return path; 94 } 95 96 /* 97 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we 98 * believe to be the server path to this dentry 99 */ 100 static int nfs4_validate_fspath(struct dentry *dentry, 101 const struct nfs4_fs_locations *locations, 102 char *page, char *page2) 103 { 104 const char *path, *fs_path; 105 106 path = nfs4_path(dentry, page, PAGE_SIZE); 107 if (IS_ERR(path)) 108 return PTR_ERR(path); 109 110 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); 111 if (IS_ERR(fs_path)) 112 return PTR_ERR(fs_path); 113 114 if (strncmp(path, fs_path, strlen(fs_path)) != 0) { 115 dprintk("%s: path %s does not begin with fsroot %s\n", 116 __func__, path, fs_path); 117 return -ENOENT; 118 } 119 120 return 0; 121 } 122 123 static size_t nfs_parse_server_name(char *string, size_t len, 124 struct sockaddr *sa, size_t salen, struct net *net) 125 { 126 ssize_t ret; 127 128 ret = rpc_pton(net, string, len, sa, salen); 129 if (ret == 0) { 130 ret = nfs_dns_resolve_name(net, string, len, sa, salen); 131 if (ret < 0) 132 ret = 0; 133 } 134 return ret; 135 } 136 137 /** 138 * nfs_find_best_sec - Find a security mechanism supported locally 139 * @server: NFS server struct 140 * @flavors: List of security tuples returned by SECINFO procedure 141 * 142 * Return an rpc client that uses the first security mechanism in 143 * "flavors" that is locally supported. The "flavors" array 144 * is searched in the order returned from the server, per RFC 3530 145 * recommendation and each flavor is checked for membership in the 146 * sec= mount option list if it exists. 147 * 148 * Return -EPERM if no matching flavor is found in the array. 149 * 150 * Please call rpc_shutdown_client() when you are done with this rpc client. 151 * 152 */ 153 static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt, 154 struct nfs_server *server, 155 struct nfs4_secinfo_flavors *flavors) 156 { 157 rpc_authflavor_t pflavor; 158 struct nfs4_secinfo4 *secinfo; 159 unsigned int i; 160 161 for (i = 0; i < flavors->num_flavors; i++) { 162 secinfo = &flavors->flavors[i]; 163 164 switch (secinfo->flavor) { 165 case RPC_AUTH_NULL: 166 case RPC_AUTH_UNIX: 167 case RPC_AUTH_GSS: 168 pflavor = rpcauth_get_pseudoflavor(secinfo->flavor, 169 &secinfo->flavor_info); 170 /* does the pseudoflavor match a sec= mount opt? */ 171 if (pflavor != RPC_AUTH_MAXFLAVOR && 172 nfs_auth_info_match(&server->auth_info, pflavor)) { 173 struct rpc_clnt *new; 174 struct rpc_cred *cred; 175 176 /* Cloning creates an rpc_auth for the flavor */ 177 new = rpc_clone_client_set_auth(clnt, pflavor); 178 if (IS_ERR(new)) 179 continue; 180 /** 181 * Check that the user actually can use the 182 * flavor. This is mostly for RPC_AUTH_GSS 183 * where cr_init obtains a gss context 184 */ 185 cred = rpcauth_lookupcred(new->cl_auth, 0); 186 if (IS_ERR(cred)) { 187 rpc_shutdown_client(new); 188 continue; 189 } 190 put_rpccred(cred); 191 return new; 192 } 193 } 194 } 195 return ERR_PTR(-EPERM); 196 } 197 198 /** 199 * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup, 200 * return an rpc_clnt that uses the best available security flavor with 201 * respect to the secinfo flavor list and the sec= mount options. 202 * 203 * @clnt: RPC client to clone 204 * @inode: directory inode 205 * @name: lookup name 206 * 207 * Please call rpc_shutdown_client() when you are done with this rpc client. 208 */ 209 struct rpc_clnt * 210 nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode, 211 const struct qstr *name) 212 { 213 struct page *page; 214 struct nfs4_secinfo_flavors *flavors; 215 struct rpc_clnt *new; 216 int err; 217 218 page = alloc_page(GFP_KERNEL); 219 if (!page) 220 return ERR_PTR(-ENOMEM); 221 222 flavors = page_address(page); 223 224 err = nfs4_proc_secinfo(inode, name, flavors); 225 if (err < 0) { 226 new = ERR_PTR(err); 227 goto out; 228 } 229 230 new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors); 231 232 out: 233 put_page(page); 234 return new; 235 } 236 237 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 238 char *page, char *page2, 239 const struct nfs4_fs_location *location) 240 { 241 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 242 struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client); 243 struct vfsmount *mnt = ERR_PTR(-ENOENT); 244 char *mnt_path; 245 unsigned int maxbuflen; 246 unsigned int s; 247 248 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 249 if (IS_ERR(mnt_path)) 250 return ERR_CAST(mnt_path); 251 mountdata->mnt_path = mnt_path; 252 maxbuflen = mnt_path - 1 - page2; 253 254 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL); 255 if (mountdata->addr == NULL) 256 return ERR_PTR(-ENOMEM); 257 258 for (s = 0; s < location->nservers; s++) { 259 const struct nfs4_string *buf = &location->servers[s]; 260 261 if (buf->len <= 0 || buf->len >= maxbuflen) 262 continue; 263 264 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) 265 continue; 266 267 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len, 268 mountdata->addr, addr_bufsize, net); 269 if (mountdata->addrlen == 0) 270 continue; 271 272 rpc_set_port(mountdata->addr, NFS_PORT); 273 274 memcpy(page2, buf->data, buf->len); 275 page2[buf->len] = '\0'; 276 mountdata->hostname = page2; 277 278 snprintf(page, PAGE_SIZE, "%s:%s", 279 mountdata->hostname, 280 mountdata->mnt_path); 281 282 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); 283 if (!IS_ERR(mnt)) 284 break; 285 } 286 kfree(mountdata->addr); 287 return mnt; 288 } 289 290 /** 291 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 292 * @dentry - parent directory 293 * @locations - array of NFSv4 server location information 294 * 295 */ 296 static struct vfsmount *nfs_follow_referral(struct dentry *dentry, 297 const struct nfs4_fs_locations *locations) 298 { 299 struct vfsmount *mnt = ERR_PTR(-ENOENT); 300 struct nfs_clone_mount mountdata = { 301 .sb = dentry->d_sb, 302 .dentry = dentry, 303 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor, 304 }; 305 char *page = NULL, *page2 = NULL; 306 int loc, error; 307 308 if (locations == NULL || locations->nlocations <= 0) 309 goto out; 310 311 dprintk("%s: referral at %pd2\n", __func__, dentry); 312 313 page = (char *) __get_free_page(GFP_USER); 314 if (!page) 315 goto out; 316 317 page2 = (char *) __get_free_page(GFP_USER); 318 if (!page2) 319 goto out; 320 321 /* Ensure fs path is a prefix of current dentry path */ 322 error = nfs4_validate_fspath(dentry, locations, page, page2); 323 if (error < 0) { 324 mnt = ERR_PTR(error); 325 goto out; 326 } 327 328 for (loc = 0; loc < locations->nlocations; loc++) { 329 const struct nfs4_fs_location *location = &locations->locations[loc]; 330 331 if (location == NULL || location->nservers <= 0 || 332 location->rootpath.ncomponents == 0) 333 continue; 334 335 mnt = try_location(&mountdata, page, page2, location); 336 if (!IS_ERR(mnt)) 337 break; 338 } 339 340 out: 341 free_page((unsigned long) page); 342 free_page((unsigned long) page2); 343 dprintk("%s: done\n", __func__); 344 return mnt; 345 } 346 347 /* 348 * nfs_do_refmount - handle crossing a referral on server 349 * @dentry - dentry of referral 350 * 351 */ 352 static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry) 353 { 354 struct vfsmount *mnt = ERR_PTR(-ENOMEM); 355 struct dentry *parent; 356 struct nfs4_fs_locations *fs_locations = NULL; 357 struct page *page; 358 int err; 359 360 /* BUG_ON(IS_ROOT(dentry)); */ 361 dprintk("%s: enter\n", __func__); 362 363 page = alloc_page(GFP_KERNEL); 364 if (page == NULL) 365 goto out; 366 367 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 368 if (fs_locations == NULL) 369 goto out_free; 370 371 /* Get locations */ 372 mnt = ERR_PTR(-ENOENT); 373 374 parent = dget_parent(dentry); 375 dprintk("%s: getting locations for %pd2\n", 376 __func__, dentry); 377 378 err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page); 379 dput(parent); 380 if (err != 0 || 381 fs_locations->nlocations <= 0 || 382 fs_locations->fs_path.ncomponents <= 0) 383 goto out_free; 384 385 mnt = nfs_follow_referral(dentry, fs_locations); 386 out_free: 387 __free_page(page); 388 kfree(fs_locations); 389 out: 390 dprintk("%s: done\n", __func__); 391 return mnt; 392 } 393 394 struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry, 395 struct nfs_fh *fh, struct nfs_fattr *fattr) 396 { 397 rpc_authflavor_t flavor = server->client->cl_auth->au_flavor; 398 struct dentry *parent = dget_parent(dentry); 399 struct inode *dir = d_inode(parent); 400 const struct qstr *name = &dentry->d_name; 401 struct rpc_clnt *client; 402 struct vfsmount *mnt; 403 404 /* Look it up again to get its attributes and sec flavor */ 405 client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr); 406 dput(parent); 407 if (IS_ERR(client)) 408 return ERR_CAST(client); 409 410 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) { 411 mnt = nfs_do_refmount(client, dentry); 412 goto out; 413 } 414 415 if (client->cl_auth->au_flavor != flavor) 416 flavor = client->cl_auth->au_flavor; 417 mnt = nfs_do_submount(dentry, fh, fattr, flavor); 418 out: 419 rpc_shutdown_client(client); 420 return mnt; 421 } 422 423 /* 424 * Try one location from the fs_locations array. 425 * 426 * Returns zero on success, or a negative errno value. 427 */ 428 static int nfs4_try_replacing_one_location(struct nfs_server *server, 429 char *page, char *page2, 430 const struct nfs4_fs_location *location) 431 { 432 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 433 struct net *net = rpc_net_ns(server->client); 434 struct sockaddr *sap; 435 unsigned int s; 436 size_t salen; 437 int error; 438 439 sap = kmalloc(addr_bufsize, GFP_KERNEL); 440 if (sap == NULL) 441 return -ENOMEM; 442 443 error = -ENOENT; 444 for (s = 0; s < location->nservers; s++) { 445 const struct nfs4_string *buf = &location->servers[s]; 446 char *hostname; 447 448 if (buf->len <= 0 || buf->len > PAGE_SIZE) 449 continue; 450 451 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL) 452 continue; 453 454 salen = nfs_parse_server_name(buf->data, buf->len, 455 sap, addr_bufsize, net); 456 if (salen == 0) 457 continue; 458 rpc_set_port(sap, NFS_PORT); 459 460 error = -ENOMEM; 461 hostname = kstrndup(buf->data, buf->len, GFP_KERNEL); 462 if (hostname == NULL) 463 break; 464 465 error = nfs4_update_server(server, hostname, sap, salen, net); 466 kfree(hostname); 467 if (error == 0) 468 break; 469 } 470 471 kfree(sap); 472 return error; 473 } 474 475 /** 476 * nfs4_replace_transport - set up transport to destination server 477 * 478 * @server: export being migrated 479 * @locations: fs_locations array 480 * 481 * Returns zero on success, or a negative errno value. 482 * 483 * The client tries all the entries in the "locations" array, in the 484 * order returned by the server, until one works or the end of the 485 * array is reached. 486 */ 487 int nfs4_replace_transport(struct nfs_server *server, 488 const struct nfs4_fs_locations *locations) 489 { 490 char *page = NULL, *page2 = NULL; 491 int loc, error; 492 493 error = -ENOENT; 494 if (locations == NULL || locations->nlocations <= 0) 495 goto out; 496 497 error = -ENOMEM; 498 page = (char *) __get_free_page(GFP_USER); 499 if (!page) 500 goto out; 501 page2 = (char *) __get_free_page(GFP_USER); 502 if (!page2) 503 goto out; 504 505 for (loc = 0; loc < locations->nlocations; loc++) { 506 const struct nfs4_fs_location *location = 507 &locations->locations[loc]; 508 509 if (location == NULL || location->nservers <= 0 || 510 location->rootpath.ncomponents == 0) 511 continue; 512 513 error = nfs4_try_replacing_one_location(server, page, 514 page2, location); 515 if (error == 0) 516 break; 517 } 518 519 out: 520 free_page((unsigned long)page); 521 free_page((unsigned long)page2); 522 return error; 523 } 524