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/slab.h> 15 #include <linux/string.h> 16 #include <linux/sunrpc/clnt.h> 17 #include <linux/sunrpc/addr.h> 18 #include <linux/vfs.h> 19 #include <linux/inet.h> 20 #include "internal.h" 21 #include "nfs4_fs.h" 22 #include "dns_resolve.h" 23 24 #define NFSDBG_FACILITY NFSDBG_VFS 25 26 /* 27 * Convert the NFSv4 pathname components into a standard posix path. 28 * 29 * Note that the resulting string will be placed at the end of the buffer 30 */ 31 static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname, 32 char *buffer, ssize_t buflen) 33 { 34 char *end = buffer + buflen; 35 int n; 36 37 *--end = '\0'; 38 buflen--; 39 40 n = pathname->ncomponents; 41 while (--n >= 0) { 42 const struct nfs4_string *component = &pathname->components[n]; 43 buflen -= component->len + 1; 44 if (buflen < 0) 45 goto Elong; 46 end -= component->len; 47 memcpy(end, component->data, component->len); 48 *--end = '/'; 49 } 50 return end; 51 Elong: 52 return ERR_PTR(-ENAMETOOLONG); 53 } 54 55 /* 56 * return the path component of "<server>:<path>" 57 * nfspath - the "<server>:<path>" string 58 * end - one past the last char that could contain "<server>:" 59 * returns NULL on failure 60 */ 61 static char *nfs_path_component(const char *nfspath, const char *end) 62 { 63 char *p; 64 65 if (*nfspath == '[') { 66 /* parse [] escaped IPv6 addrs */ 67 p = strchr(nfspath, ']'); 68 if (p != NULL && ++p < end && *p == ':') 69 return p + 1; 70 } else { 71 /* otherwise split on first colon */ 72 p = strchr(nfspath, ':'); 73 if (p != NULL && p < end) 74 return p + 1; 75 } 76 return NULL; 77 } 78 79 /* 80 * Determine the mount path as a string 81 */ 82 static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen) 83 { 84 char *limit; 85 char *path = nfs_path(&limit, dentry, buffer, buflen, 86 NFS_PATH_CANONICAL); 87 if (!IS_ERR(path)) { 88 char *path_component = nfs_path_component(path, limit); 89 if (path_component) 90 return path_component; 91 } 92 return path; 93 } 94 95 /* 96 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we 97 * believe to be the server path to this dentry 98 */ 99 static int nfs4_validate_fspath(struct dentry *dentry, 100 const struct nfs4_fs_locations *locations, 101 char *page, char *page2) 102 { 103 const char *path, *fs_path; 104 105 path = nfs4_path(dentry, page, PAGE_SIZE); 106 if (IS_ERR(path)) 107 return PTR_ERR(path); 108 109 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); 110 if (IS_ERR(fs_path)) 111 return PTR_ERR(fs_path); 112 113 if (strncmp(path, fs_path, strlen(fs_path)) != 0) { 114 dprintk("%s: path %s does not begin with fsroot %s\n", 115 __func__, path, fs_path); 116 return -ENOENT; 117 } 118 119 return 0; 120 } 121 122 static size_t nfs_parse_server_name(char *string, size_t len, 123 struct sockaddr *sa, size_t salen, struct nfs_server *server) 124 { 125 struct net *net = rpc_net_ns(server->client); 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 rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors) 138 { 139 struct gss_api_mech *mech; 140 struct xdr_netobj oid; 141 int i; 142 rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX; 143 144 for (i = 0; i < flavors->num_flavors; i++) { 145 struct nfs4_secinfo_flavor *flavor; 146 flavor = &flavors->flavors[i]; 147 148 if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) { 149 pseudoflavor = flavor->flavor; 150 break; 151 } else if (flavor->flavor == RPC_AUTH_GSS) { 152 oid.len = flavor->gss.sec_oid4.len; 153 oid.data = flavor->gss.sec_oid4.data; 154 mech = gss_mech_get_by_OID(&oid); 155 if (!mech) 156 continue; 157 pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service); 158 gss_mech_put(mech); 159 break; 160 } 161 } 162 163 return pseudoflavor; 164 } 165 166 static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name) 167 { 168 struct page *page; 169 struct nfs4_secinfo_flavors *flavors; 170 rpc_authflavor_t flavor; 171 int err; 172 173 page = alloc_page(GFP_KERNEL); 174 if (!page) 175 return -ENOMEM; 176 flavors = page_address(page); 177 178 err = nfs4_proc_secinfo(inode, name, flavors); 179 if (err < 0) { 180 flavor = err; 181 goto out; 182 } 183 184 flavor = nfs_find_best_sec(flavors); 185 186 out: 187 put_page(page); 188 return flavor; 189 } 190 191 /* 192 * Please call rpc_shutdown_client() when you are done with this client. 193 */ 194 struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode, 195 struct qstr *name) 196 { 197 rpc_authflavor_t flavor; 198 199 flavor = nfs4_negotiate_security(inode, name); 200 if ((int)flavor < 0) 201 return ERR_PTR((int)flavor); 202 203 return rpc_clone_client_set_auth(clnt, flavor); 204 } 205 206 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 207 char *page, char *page2, 208 const struct nfs4_fs_location *location) 209 { 210 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 211 struct vfsmount *mnt = ERR_PTR(-ENOENT); 212 char *mnt_path; 213 unsigned int maxbuflen; 214 unsigned int s; 215 216 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 217 if (IS_ERR(mnt_path)) 218 return ERR_CAST(mnt_path); 219 mountdata->mnt_path = mnt_path; 220 maxbuflen = mnt_path - 1 - page2; 221 222 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL); 223 if (mountdata->addr == NULL) 224 return ERR_PTR(-ENOMEM); 225 226 for (s = 0; s < location->nservers; s++) { 227 const struct nfs4_string *buf = &location->servers[s]; 228 229 if (buf->len <= 0 || buf->len >= maxbuflen) 230 continue; 231 232 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) 233 continue; 234 235 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len, 236 mountdata->addr, addr_bufsize, 237 NFS_SB(mountdata->sb)); 238 if (mountdata->addrlen == 0) 239 continue; 240 241 rpc_set_port(mountdata->addr, NFS_PORT); 242 243 memcpy(page2, buf->data, buf->len); 244 page2[buf->len] = '\0'; 245 mountdata->hostname = page2; 246 247 snprintf(page, PAGE_SIZE, "%s:%s", 248 mountdata->hostname, 249 mountdata->mnt_path); 250 251 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); 252 if (!IS_ERR(mnt)) 253 break; 254 } 255 kfree(mountdata->addr); 256 return mnt; 257 } 258 259 /** 260 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 261 * @dentry - parent directory 262 * @locations - array of NFSv4 server location information 263 * 264 */ 265 static struct vfsmount *nfs_follow_referral(struct dentry *dentry, 266 const struct nfs4_fs_locations *locations) 267 { 268 struct vfsmount *mnt = ERR_PTR(-ENOENT); 269 struct nfs_clone_mount mountdata = { 270 .sb = dentry->d_sb, 271 .dentry = dentry, 272 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor, 273 }; 274 char *page = NULL, *page2 = NULL; 275 int loc, error; 276 277 if (locations == NULL || locations->nlocations <= 0) 278 goto out; 279 280 dprintk("%s: referral at %s/%s\n", __func__, 281 dentry->d_parent->d_name.name, dentry->d_name.name); 282 283 page = (char *) __get_free_page(GFP_USER); 284 if (!page) 285 goto out; 286 287 page2 = (char *) __get_free_page(GFP_USER); 288 if (!page2) 289 goto out; 290 291 /* Ensure fs path is a prefix of current dentry path */ 292 error = nfs4_validate_fspath(dentry, locations, page, page2); 293 if (error < 0) { 294 mnt = ERR_PTR(error); 295 goto out; 296 } 297 298 for (loc = 0; loc < locations->nlocations; loc++) { 299 const struct nfs4_fs_location *location = &locations->locations[loc]; 300 301 if (location == NULL || location->nservers <= 0 || 302 location->rootpath.ncomponents == 0) 303 continue; 304 305 mnt = try_location(&mountdata, page, page2, location); 306 if (!IS_ERR(mnt)) 307 break; 308 } 309 310 out: 311 free_page((unsigned long) page); 312 free_page((unsigned long) page2); 313 dprintk("%s: done\n", __func__); 314 return mnt; 315 } 316 317 /* 318 * nfs_do_refmount - handle crossing a referral on server 319 * @dentry - dentry of referral 320 * 321 */ 322 static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry) 323 { 324 struct vfsmount *mnt = ERR_PTR(-ENOMEM); 325 struct dentry *parent; 326 struct nfs4_fs_locations *fs_locations = NULL; 327 struct page *page; 328 int err; 329 330 /* BUG_ON(IS_ROOT(dentry)); */ 331 dprintk("%s: enter\n", __func__); 332 333 page = alloc_page(GFP_KERNEL); 334 if (page == NULL) 335 goto out; 336 337 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 338 if (fs_locations == NULL) 339 goto out_free; 340 341 /* Get locations */ 342 mnt = ERR_PTR(-ENOENT); 343 344 parent = dget_parent(dentry); 345 dprintk("%s: getting locations for %s/%s\n", 346 __func__, parent->d_name.name, dentry->d_name.name); 347 348 err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page); 349 dput(parent); 350 if (err != 0 || 351 fs_locations->nlocations <= 0 || 352 fs_locations->fs_path.ncomponents <= 0) 353 goto out_free; 354 355 mnt = nfs_follow_referral(dentry, fs_locations); 356 out_free: 357 __free_page(page); 358 kfree(fs_locations); 359 out: 360 dprintk("%s: done\n", __func__); 361 return mnt; 362 } 363 364 struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry, 365 struct nfs_fh *fh, struct nfs_fattr *fattr) 366 { 367 struct dentry *parent = dget_parent(dentry); 368 struct rpc_clnt *client; 369 struct vfsmount *mnt; 370 371 /* Look it up again to get its attributes and sec flavor */ 372 client = nfs4_proc_lookup_mountpoint(parent->d_inode, &dentry->d_name, fh, fattr); 373 dput(parent); 374 if (IS_ERR(client)) 375 return ERR_CAST(client); 376 377 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) 378 mnt = nfs_do_refmount(client, dentry); 379 else 380 mnt = nfs_do_submount(dentry, fh, fattr, client->cl_auth->au_flavor); 381 382 rpc_shutdown_client(client); 383 return mnt; 384 } 385