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 * @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 rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors) 149 { 150 rpc_authflavor_t pseudoflavor; 151 struct nfs4_secinfo4 *secinfo; 152 unsigned int i; 153 154 for (i = 0; i < flavors->num_flavors; i++) { 155 secinfo = &flavors->flavors[i]; 156 157 switch (secinfo->flavor) { 158 case RPC_AUTH_NULL: 159 case RPC_AUTH_UNIX: 160 case RPC_AUTH_GSS: 161 pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor, 162 &secinfo->flavor_info); 163 if (pseudoflavor != RPC_AUTH_MAXFLAVOR) 164 return pseudoflavor; 165 break; 166 } 167 } 168 169 return RPC_AUTH_UNIX; 170 } 171 172 static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name) 173 { 174 struct page *page; 175 struct nfs4_secinfo_flavors *flavors; 176 rpc_authflavor_t flavor; 177 int err; 178 179 page = alloc_page(GFP_KERNEL); 180 if (!page) 181 return -ENOMEM; 182 flavors = page_address(page); 183 184 err = nfs4_proc_secinfo(inode, name, flavors); 185 if (err < 0) { 186 flavor = err; 187 goto out; 188 } 189 190 flavor = nfs_find_best_sec(flavors); 191 192 out: 193 put_page(page); 194 return flavor; 195 } 196 197 /* 198 * Please call rpc_shutdown_client() when you are done with this client. 199 */ 200 struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode, 201 struct qstr *name) 202 { 203 rpc_authflavor_t flavor; 204 205 flavor = nfs4_negotiate_security(inode, name); 206 if ((int)flavor < 0) 207 return ERR_PTR((int)flavor); 208 209 return rpc_clone_client_set_auth(clnt, flavor); 210 } 211 212 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 213 char *page, char *page2, 214 const struct nfs4_fs_location *location) 215 { 216 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 217 struct vfsmount *mnt = ERR_PTR(-ENOENT); 218 char *mnt_path; 219 unsigned int maxbuflen; 220 unsigned int s; 221 222 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 223 if (IS_ERR(mnt_path)) 224 return ERR_CAST(mnt_path); 225 mountdata->mnt_path = mnt_path; 226 maxbuflen = mnt_path - 1 - page2; 227 228 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL); 229 if (mountdata->addr == NULL) 230 return ERR_PTR(-ENOMEM); 231 232 for (s = 0; s < location->nservers; s++) { 233 const struct nfs4_string *buf = &location->servers[s]; 234 235 if (buf->len <= 0 || buf->len >= maxbuflen) 236 continue; 237 238 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) 239 continue; 240 241 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len, 242 mountdata->addr, addr_bufsize, 243 NFS_SB(mountdata->sb)); 244 if (mountdata->addrlen == 0) 245 continue; 246 247 rpc_set_port(mountdata->addr, NFS_PORT); 248 249 memcpy(page2, buf->data, buf->len); 250 page2[buf->len] = '\0'; 251 mountdata->hostname = page2; 252 253 snprintf(page, PAGE_SIZE, "%s:%s", 254 mountdata->hostname, 255 mountdata->mnt_path); 256 257 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); 258 if (!IS_ERR(mnt)) 259 break; 260 } 261 kfree(mountdata->addr); 262 return mnt; 263 } 264 265 /** 266 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 267 * @dentry - parent directory 268 * @locations - array of NFSv4 server location information 269 * 270 */ 271 static struct vfsmount *nfs_follow_referral(struct dentry *dentry, 272 const struct nfs4_fs_locations *locations) 273 { 274 struct vfsmount *mnt = ERR_PTR(-ENOENT); 275 struct nfs_clone_mount mountdata = { 276 .sb = dentry->d_sb, 277 .dentry = dentry, 278 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor, 279 }; 280 char *page = NULL, *page2 = NULL; 281 int loc, error; 282 283 if (locations == NULL || locations->nlocations <= 0) 284 goto out; 285 286 dprintk("%s: referral at %s/%s\n", __func__, 287 dentry->d_parent->d_name.name, dentry->d_name.name); 288 289 page = (char *) __get_free_page(GFP_USER); 290 if (!page) 291 goto out; 292 293 page2 = (char *) __get_free_page(GFP_USER); 294 if (!page2) 295 goto out; 296 297 /* Ensure fs path is a prefix of current dentry path */ 298 error = nfs4_validate_fspath(dentry, locations, page, page2); 299 if (error < 0) { 300 mnt = ERR_PTR(error); 301 goto out; 302 } 303 304 for (loc = 0; loc < locations->nlocations; loc++) { 305 const struct nfs4_fs_location *location = &locations->locations[loc]; 306 307 if (location == NULL || location->nservers <= 0 || 308 location->rootpath.ncomponents == 0) 309 continue; 310 311 mnt = try_location(&mountdata, page, page2, location); 312 if (!IS_ERR(mnt)) 313 break; 314 } 315 316 out: 317 free_page((unsigned long) page); 318 free_page((unsigned long) page2); 319 dprintk("%s: done\n", __func__); 320 return mnt; 321 } 322 323 /* 324 * nfs_do_refmount - handle crossing a referral on server 325 * @dentry - dentry of referral 326 * 327 */ 328 static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry) 329 { 330 struct vfsmount *mnt = ERR_PTR(-ENOMEM); 331 struct dentry *parent; 332 struct nfs4_fs_locations *fs_locations = NULL; 333 struct page *page; 334 int err; 335 336 /* BUG_ON(IS_ROOT(dentry)); */ 337 dprintk("%s: enter\n", __func__); 338 339 page = alloc_page(GFP_KERNEL); 340 if (page == NULL) 341 goto out; 342 343 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 344 if (fs_locations == NULL) 345 goto out_free; 346 347 /* Get locations */ 348 mnt = ERR_PTR(-ENOENT); 349 350 parent = dget_parent(dentry); 351 dprintk("%s: getting locations for %s/%s\n", 352 __func__, parent->d_name.name, dentry->d_name.name); 353 354 err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page); 355 dput(parent); 356 if (err != 0 || 357 fs_locations->nlocations <= 0 || 358 fs_locations->fs_path.ncomponents <= 0) 359 goto out_free; 360 361 mnt = nfs_follow_referral(dentry, fs_locations); 362 out_free: 363 __free_page(page); 364 kfree(fs_locations); 365 out: 366 dprintk("%s: done\n", __func__); 367 return mnt; 368 } 369 370 struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry, 371 struct nfs_fh *fh, struct nfs_fattr *fattr) 372 { 373 rpc_authflavor_t flavor = server->client->cl_auth->au_flavor; 374 struct dentry *parent = dget_parent(dentry); 375 struct inode *dir = parent->d_inode; 376 struct qstr *name = &dentry->d_name; 377 struct rpc_clnt *client; 378 struct vfsmount *mnt; 379 380 /* Look it up again to get its attributes and sec flavor */ 381 client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr); 382 dput(parent); 383 if (IS_ERR(client)) 384 return ERR_CAST(client); 385 386 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) { 387 mnt = nfs_do_refmount(client, dentry); 388 goto out; 389 } 390 391 if (client->cl_auth->au_flavor != flavor) 392 flavor = client->cl_auth->au_flavor; 393 else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) { 394 rpc_authflavor_t new = nfs4_negotiate_security(dir, name); 395 if ((int)new >= 0) 396 flavor = new; 397 } 398 mnt = nfs_do_submount(dentry, fh, fattr, flavor); 399 out: 400 rpc_shutdown_client(client); 401 return mnt; 402 } 403