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 the pseudoflavor of the first security mechanism in 143 * "flavors" that is locally supported. Return RPC_AUTH_UNIX if 144 * no matching flavor is found in the array. The "flavors" array 145 * is searched in the order returned from the server, per RFC 3530 146 * recommendation. 147 */ 148 static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server, 149 struct nfs4_secinfo_flavors *flavors) 150 { 151 rpc_authflavor_t pseudoflavor; 152 struct nfs4_secinfo4 *secinfo; 153 unsigned int i; 154 155 for (i = 0; i < flavors->num_flavors; i++) { 156 secinfo = &flavors->flavors[i]; 157 158 switch (secinfo->flavor) { 159 case RPC_AUTH_NULL: 160 case RPC_AUTH_UNIX: 161 case RPC_AUTH_GSS: 162 pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor, 163 &secinfo->flavor_info); 164 /* make sure pseudoflavor matches sec= mount opt */ 165 if (pseudoflavor != RPC_AUTH_MAXFLAVOR && 166 nfs_auth_info_match(&server->auth_info, 167 pseudoflavor)) 168 return pseudoflavor; 169 break; 170 } 171 } 172 173 /* if there were any sec= options then nothing matched */ 174 if (server->auth_info.flavor_len > 0) 175 return -EPERM; 176 177 return RPC_AUTH_UNIX; 178 } 179 180 static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name) 181 { 182 struct page *page; 183 struct nfs4_secinfo_flavors *flavors; 184 rpc_authflavor_t flavor; 185 int err; 186 187 page = alloc_page(GFP_KERNEL); 188 if (!page) 189 return -ENOMEM; 190 flavors = page_address(page); 191 192 err = nfs4_proc_secinfo(inode, name, flavors); 193 if (err < 0) { 194 flavor = err; 195 goto out; 196 } 197 198 flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors); 199 200 out: 201 put_page(page); 202 return flavor; 203 } 204 205 /* 206 * Please call rpc_shutdown_client() when you are done with this client. 207 */ 208 struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode, 209 struct qstr *name) 210 { 211 rpc_authflavor_t flavor; 212 213 flavor = nfs4_negotiate_security(inode, name); 214 if ((int)flavor < 0) 215 return ERR_PTR((int)flavor); 216 217 return rpc_clone_client_set_auth(clnt, flavor); 218 } 219 220 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 221 char *page, char *page2, 222 const struct nfs4_fs_location *location) 223 { 224 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 225 struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client); 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, net); 252 if (mountdata->addrlen == 0) 253 continue; 254 255 rpc_set_port(mountdata->addr, NFS_PORT); 256 257 memcpy(page2, buf->data, buf->len); 258 page2[buf->len] = '\0'; 259 mountdata->hostname = page2; 260 261 snprintf(page, PAGE_SIZE, "%s:%s", 262 mountdata->hostname, 263 mountdata->mnt_path); 264 265 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); 266 if (!IS_ERR(mnt)) 267 break; 268 } 269 kfree(mountdata->addr); 270 return mnt; 271 } 272 273 /** 274 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 275 * @dentry - parent directory 276 * @locations - array of NFSv4 server location information 277 * 278 */ 279 static struct vfsmount *nfs_follow_referral(struct dentry *dentry, 280 const struct nfs4_fs_locations *locations) 281 { 282 struct vfsmount *mnt = ERR_PTR(-ENOENT); 283 struct nfs_clone_mount mountdata = { 284 .sb = dentry->d_sb, 285 .dentry = dentry, 286 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor, 287 }; 288 char *page = NULL, *page2 = NULL; 289 int loc, error; 290 291 if (locations == NULL || locations->nlocations <= 0) 292 goto out; 293 294 dprintk("%s: referral at %pd2\n", __func__, dentry); 295 296 page = (char *) __get_free_page(GFP_USER); 297 if (!page) 298 goto out; 299 300 page2 = (char *) __get_free_page(GFP_USER); 301 if (!page2) 302 goto out; 303 304 /* Ensure fs path is a prefix of current dentry path */ 305 error = nfs4_validate_fspath(dentry, locations, page, page2); 306 if (error < 0) { 307 mnt = ERR_PTR(error); 308 goto out; 309 } 310 311 for (loc = 0; loc < locations->nlocations; loc++) { 312 const struct nfs4_fs_location *location = &locations->locations[loc]; 313 314 if (location == NULL || location->nservers <= 0 || 315 location->rootpath.ncomponents == 0) 316 continue; 317 318 mnt = try_location(&mountdata, page, page2, location); 319 if (!IS_ERR(mnt)) 320 break; 321 } 322 323 out: 324 free_page((unsigned long) page); 325 free_page((unsigned long) page2); 326 dprintk("%s: done\n", __func__); 327 return mnt; 328 } 329 330 /* 331 * nfs_do_refmount - handle crossing a referral on server 332 * @dentry - dentry of referral 333 * 334 */ 335 static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry) 336 { 337 struct vfsmount *mnt = ERR_PTR(-ENOMEM); 338 struct dentry *parent; 339 struct nfs4_fs_locations *fs_locations = NULL; 340 struct page *page; 341 int err; 342 343 /* BUG_ON(IS_ROOT(dentry)); */ 344 dprintk("%s: enter\n", __func__); 345 346 page = alloc_page(GFP_KERNEL); 347 if (page == NULL) 348 goto out; 349 350 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 351 if (fs_locations == NULL) 352 goto out_free; 353 354 /* Get locations */ 355 mnt = ERR_PTR(-ENOENT); 356 357 parent = dget_parent(dentry); 358 dprintk("%s: getting locations for %pd2\n", 359 __func__, dentry); 360 361 err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page); 362 dput(parent); 363 if (err != 0 || 364 fs_locations->nlocations <= 0 || 365 fs_locations->fs_path.ncomponents <= 0) 366 goto out_free; 367 368 mnt = nfs_follow_referral(dentry, fs_locations); 369 out_free: 370 __free_page(page); 371 kfree(fs_locations); 372 out: 373 dprintk("%s: done\n", __func__); 374 return mnt; 375 } 376 377 struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry, 378 struct nfs_fh *fh, struct nfs_fattr *fattr) 379 { 380 rpc_authflavor_t flavor = server->client->cl_auth->au_flavor; 381 struct dentry *parent = dget_parent(dentry); 382 struct inode *dir = parent->d_inode; 383 struct qstr *name = &dentry->d_name; 384 struct rpc_clnt *client; 385 struct vfsmount *mnt; 386 387 /* Look it up again to get its attributes and sec flavor */ 388 client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr); 389 dput(parent); 390 if (IS_ERR(client)) 391 return ERR_CAST(client); 392 393 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) { 394 mnt = nfs_do_refmount(client, dentry); 395 goto out; 396 } 397 398 if (client->cl_auth->au_flavor != flavor) 399 flavor = client->cl_auth->au_flavor; 400 else { 401 rpc_authflavor_t new = nfs4_negotiate_security(dir, name); 402 if ((int)new >= 0) 403 flavor = new; 404 } 405 mnt = nfs_do_submount(dentry, fh, fattr, flavor); 406 out: 407 rpc_shutdown_client(client); 408 return mnt; 409 } 410 411 /* 412 * Try one location from the fs_locations array. 413 * 414 * Returns zero on success, or a negative errno value. 415 */ 416 static int nfs4_try_replacing_one_location(struct nfs_server *server, 417 char *page, char *page2, 418 const struct nfs4_fs_location *location) 419 { 420 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 421 struct net *net = rpc_net_ns(server->client); 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, net); 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, net); 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