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 nfs_server *server) 125 { 126 struct net *net = rpc_net_ns(server->client); 127 ssize_t ret; 128 129 ret = rpc_pton(net, string, len, sa, salen); 130 if (ret == 0) { 131 ret = nfs_dns_resolve_name(net, string, len, sa, salen); 132 if (ret < 0) 133 ret = 0; 134 } 135 return ret; 136 } 137 138 /** 139 * nfs_find_best_sec - Find a security mechanism supported locally 140 * @server: NFS server struct 141 * @flavors: List of security tuples returned by SECINFO procedure 142 * 143 * Return the pseudoflavor of the first security mechanism in 144 * "flavors" that is locally supported. Return RPC_AUTH_UNIX if 145 * no matching flavor is found in the array. The "flavors" array 146 * is searched in the order returned from the server, per RFC 3530 147 * recommendation. 148 */ 149 static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server, 150 struct nfs4_secinfo_flavors *flavors) 151 { 152 rpc_authflavor_t pseudoflavor; 153 struct nfs4_secinfo4 *secinfo; 154 unsigned int i; 155 156 for (i = 0; i < flavors->num_flavors; i++) { 157 secinfo = &flavors->flavors[i]; 158 159 switch (secinfo->flavor) { 160 case RPC_AUTH_NULL: 161 case RPC_AUTH_UNIX: 162 case RPC_AUTH_GSS: 163 pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor, 164 &secinfo->flavor_info); 165 /* make sure pseudoflavor matches sec= mount opt */ 166 if (pseudoflavor != RPC_AUTH_MAXFLAVOR && 167 nfs_auth_info_match(&server->auth_info, 168 pseudoflavor)) 169 return pseudoflavor; 170 break; 171 } 172 } 173 174 /* if there were any sec= options then nothing matched */ 175 if (server->auth_info.flavor_len > 0) 176 return -EPERM; 177 178 return RPC_AUTH_UNIX; 179 } 180 181 static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name) 182 { 183 struct page *page; 184 struct nfs4_secinfo_flavors *flavors; 185 rpc_authflavor_t flavor; 186 int err; 187 188 page = alloc_page(GFP_KERNEL); 189 if (!page) 190 return -ENOMEM; 191 flavors = page_address(page); 192 193 err = nfs4_proc_secinfo(inode, name, flavors); 194 if (err < 0) { 195 flavor = err; 196 goto out; 197 } 198 199 flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors); 200 201 out: 202 put_page(page); 203 return flavor; 204 } 205 206 /* 207 * Please call rpc_shutdown_client() when you are done with this client. 208 */ 209 struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode, 210 struct qstr *name) 211 { 212 rpc_authflavor_t flavor; 213 214 flavor = nfs4_negotiate_security(inode, name); 215 if ((int)flavor < 0) 216 return ERR_PTR((int)flavor); 217 218 return rpc_clone_client_set_auth(clnt, flavor); 219 } 220 221 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 222 char *page, char *page2, 223 const struct nfs4_fs_location *location) 224 { 225 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 226 struct vfsmount *mnt = ERR_PTR(-ENOENT); 227 char *mnt_path; 228 unsigned int maxbuflen; 229 unsigned int s; 230 231 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 232 if (IS_ERR(mnt_path)) 233 return ERR_CAST(mnt_path); 234 mountdata->mnt_path = mnt_path; 235 maxbuflen = mnt_path - 1 - page2; 236 237 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL); 238 if (mountdata->addr == NULL) 239 return ERR_PTR(-ENOMEM); 240 241 for (s = 0; s < location->nservers; s++) { 242 const struct nfs4_string *buf = &location->servers[s]; 243 244 if (buf->len <= 0 || buf->len >= maxbuflen) 245 continue; 246 247 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) 248 continue; 249 250 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len, 251 mountdata->addr, addr_bufsize, 252 NFS_SB(mountdata->sb)); 253 if (mountdata->addrlen == 0) 254 continue; 255 256 rpc_set_port(mountdata->addr, NFS_PORT); 257 258 memcpy(page2, buf->data, buf->len); 259 page2[buf->len] = '\0'; 260 mountdata->hostname = page2; 261 262 snprintf(page, PAGE_SIZE, "%s:%s", 263 mountdata->hostname, 264 mountdata->mnt_path); 265 266 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); 267 if (!IS_ERR(mnt)) 268 break; 269 } 270 kfree(mountdata->addr); 271 return mnt; 272 } 273 274 /** 275 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 276 * @dentry - parent directory 277 * @locations - array of NFSv4 server location information 278 * 279 */ 280 static struct vfsmount *nfs_follow_referral(struct dentry *dentry, 281 const struct nfs4_fs_locations *locations) 282 { 283 struct vfsmount *mnt = ERR_PTR(-ENOENT); 284 struct nfs_clone_mount mountdata = { 285 .sb = dentry->d_sb, 286 .dentry = dentry, 287 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor, 288 }; 289 char *page = NULL, *page2 = NULL; 290 int loc, error; 291 292 if (locations == NULL || locations->nlocations <= 0) 293 goto out; 294 295 dprintk("%s: referral at %pd2\n", __func__, dentry); 296 297 page = (char *) __get_free_page(GFP_USER); 298 if (!page) 299 goto out; 300 301 page2 = (char *) __get_free_page(GFP_USER); 302 if (!page2) 303 goto out; 304 305 /* Ensure fs path is a prefix of current dentry path */ 306 error = nfs4_validate_fspath(dentry, locations, page, page2); 307 if (error < 0) { 308 mnt = ERR_PTR(error); 309 goto out; 310 } 311 312 for (loc = 0; loc < locations->nlocations; loc++) { 313 const struct nfs4_fs_location *location = &locations->locations[loc]; 314 315 if (location == NULL || location->nservers <= 0 || 316 location->rootpath.ncomponents == 0) 317 continue; 318 319 mnt = try_location(&mountdata, page, page2, location); 320 if (!IS_ERR(mnt)) 321 break; 322 } 323 324 out: 325 free_page((unsigned long) page); 326 free_page((unsigned long) page2); 327 dprintk("%s: done\n", __func__); 328 return mnt; 329 } 330 331 /* 332 * nfs_do_refmount - handle crossing a referral on server 333 * @dentry - dentry of referral 334 * 335 */ 336 static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry) 337 { 338 struct vfsmount *mnt = ERR_PTR(-ENOMEM); 339 struct dentry *parent; 340 struct nfs4_fs_locations *fs_locations = NULL; 341 struct page *page; 342 int err; 343 344 /* BUG_ON(IS_ROOT(dentry)); */ 345 dprintk("%s: enter\n", __func__); 346 347 page = alloc_page(GFP_KERNEL); 348 if (page == NULL) 349 goto out; 350 351 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 352 if (fs_locations == NULL) 353 goto out_free; 354 355 /* Get locations */ 356 mnt = ERR_PTR(-ENOENT); 357 358 parent = dget_parent(dentry); 359 dprintk("%s: getting locations for %pd2\n", 360 __func__, dentry); 361 362 err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page); 363 dput(parent); 364 if (err != 0 || 365 fs_locations->nlocations <= 0 || 366 fs_locations->fs_path.ncomponents <= 0) 367 goto out_free; 368 369 mnt = nfs_follow_referral(dentry, fs_locations); 370 out_free: 371 __free_page(page); 372 kfree(fs_locations); 373 out: 374 dprintk("%s: done\n", __func__); 375 return mnt; 376 } 377 378 struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry, 379 struct nfs_fh *fh, struct nfs_fattr *fattr) 380 { 381 rpc_authflavor_t flavor = server->client->cl_auth->au_flavor; 382 struct dentry *parent = dget_parent(dentry); 383 struct inode *dir = parent->d_inode; 384 struct qstr *name = &dentry->d_name; 385 struct rpc_clnt *client; 386 struct vfsmount *mnt; 387 388 /* Look it up again to get its attributes and sec flavor */ 389 client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr); 390 dput(parent); 391 if (IS_ERR(client)) 392 return ERR_CAST(client); 393 394 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) { 395 mnt = nfs_do_refmount(client, dentry); 396 goto out; 397 } 398 399 if (client->cl_auth->au_flavor != flavor) 400 flavor = client->cl_auth->au_flavor; 401 else { 402 rpc_authflavor_t new = nfs4_negotiate_security(dir, name); 403 if ((int)new >= 0) 404 flavor = new; 405 } 406 mnt = nfs_do_submount(dentry, fh, fattr, flavor); 407 out: 408 rpc_shutdown_client(client); 409 return mnt; 410 } 411 412 /* 413 * Try one location from the fs_locations array. 414 * 415 * Returns zero on success, or a negative errno value. 416 */ 417 static int nfs4_try_replacing_one_location(struct nfs_server *server, 418 char *page, char *page2, 419 const struct nfs4_fs_location *location) 420 { 421 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 422 struct sockaddr *sap; 423 unsigned int s; 424 size_t salen; 425 int error; 426 427 sap = kmalloc(addr_bufsize, GFP_KERNEL); 428 if (sap == NULL) 429 return -ENOMEM; 430 431 error = -ENOENT; 432 for (s = 0; s < location->nservers; s++) { 433 const struct nfs4_string *buf = &location->servers[s]; 434 char *hostname; 435 436 if (buf->len <= 0 || buf->len > PAGE_SIZE) 437 continue; 438 439 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL) 440 continue; 441 442 salen = nfs_parse_server_name(buf->data, buf->len, 443 sap, addr_bufsize, server); 444 if (salen == 0) 445 continue; 446 rpc_set_port(sap, NFS_PORT); 447 448 error = -ENOMEM; 449 hostname = kstrndup(buf->data, buf->len, GFP_KERNEL); 450 if (hostname == NULL) 451 break; 452 453 error = nfs4_update_server(server, hostname, sap, salen); 454 kfree(hostname); 455 if (error == 0) 456 break; 457 } 458 459 kfree(sap); 460 return error; 461 } 462 463 /** 464 * nfs4_replace_transport - set up transport to destination server 465 * 466 * @server: export being migrated 467 * @locations: fs_locations array 468 * 469 * Returns zero on success, or a negative errno value. 470 * 471 * The client tries all the entries in the "locations" array, in the 472 * order returned by the server, until one works or the end of the 473 * array is reached. 474 */ 475 int nfs4_replace_transport(struct nfs_server *server, 476 const struct nfs4_fs_locations *locations) 477 { 478 char *page = NULL, *page2 = NULL; 479 int loc, error; 480 481 error = -ENOENT; 482 if (locations == NULL || locations->nlocations <= 0) 483 goto out; 484 485 error = -ENOMEM; 486 page = (char *) __get_free_page(GFP_USER); 487 if (!page) 488 goto out; 489 page2 = (char *) __get_free_page(GFP_USER); 490 if (!page2) 491 goto out; 492 493 for (loc = 0; loc < locations->nlocations; loc++) { 494 const struct nfs4_fs_location *location = 495 &locations->locations[loc]; 496 497 if (location == NULL || location->nservers <= 0 || 498 location->rootpath.ncomponents == 0) 499 continue; 500 501 error = nfs4_try_replacing_one_location(server, page, 502 page2, location); 503 if (error == 0) 504 break; 505 } 506 507 out: 508 free_page((unsigned long)page); 509 free_page((unsigned long)page2); 510 return error; 511 } 512