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/vfs.h> 18 #include <linux/inet.h> 19 #include "internal.h" 20 #include "nfs4_fs.h" 21 #include "dns_resolve.h" 22 23 #define NFSDBG_FACILITY NFSDBG_VFS 24 25 /* 26 * Convert the NFSv4 pathname components into a standard posix path. 27 * 28 * Note that the resulting string will be placed at the end of the buffer 29 */ 30 static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname, 31 char *buffer, ssize_t buflen) 32 { 33 char *end = buffer + buflen; 34 int n; 35 36 *--end = '\0'; 37 buflen--; 38 39 n = pathname->ncomponents; 40 while (--n >= 0) { 41 const struct nfs4_string *component = &pathname->components[n]; 42 buflen -= component->len + 1; 43 if (buflen < 0) 44 goto Elong; 45 end -= component->len; 46 memcpy(end, component->data, component->len); 47 *--end = '/'; 48 } 49 return end; 50 Elong: 51 return ERR_PTR(-ENAMETOOLONG); 52 } 53 54 /* 55 * return the path component of "<server>:<path>" 56 * nfspath - the "<server>:<path>" string 57 * end - one past the last char that could contain "<server>:" 58 * returns NULL on failure 59 */ 60 static char *nfs_path_component(const char *nfspath, const char *end) 61 { 62 char *p; 63 64 if (*nfspath == '[') { 65 /* parse [] escaped IPv6 addrs */ 66 p = strchr(nfspath, ']'); 67 if (p != NULL && ++p < end && *p == ':') 68 return p + 1; 69 } else { 70 /* otherwise split on first colon */ 71 p = strchr(nfspath, ':'); 72 if (p != NULL && p < end) 73 return p + 1; 74 } 75 return NULL; 76 } 77 78 /* 79 * Determine the mount path as a string 80 */ 81 static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen) 82 { 83 char *limit; 84 char *path = nfs_path(&limit, dentry, buffer, buflen, 85 NFS_PATH_CANONICAL); 86 if (!IS_ERR(path)) { 87 char *path_component = nfs_path_component(path, limit); 88 if (path_component) 89 return path_component; 90 } 91 return path; 92 } 93 94 /* 95 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we 96 * believe to be the server path to this dentry 97 */ 98 static int nfs4_validate_fspath(struct dentry *dentry, 99 const struct nfs4_fs_locations *locations, 100 char *page, char *page2) 101 { 102 const char *path, *fs_path; 103 104 path = nfs4_path(dentry, page, PAGE_SIZE); 105 if (IS_ERR(path)) 106 return PTR_ERR(path); 107 108 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); 109 if (IS_ERR(fs_path)) 110 return PTR_ERR(fs_path); 111 112 if (strncmp(path, fs_path, strlen(fs_path)) != 0) { 113 dprintk("%s: path %s does not begin with fsroot %s\n", 114 __func__, path, fs_path); 115 return -ENOENT; 116 } 117 118 return 0; 119 } 120 121 static size_t nfs_parse_server_name(char *string, size_t len, 122 struct sockaddr *sa, size_t salen, struct nfs_server *server) 123 { 124 struct net *net = rpc_net_ns(server->client); 125 ssize_t ret; 126 127 ret = rpc_pton(net, string, len, sa, salen); 128 if (ret == 0) { 129 ret = nfs_dns_resolve_name(net, string, len, sa, salen); 130 if (ret < 0) 131 ret = 0; 132 } 133 return ret; 134 } 135 136 rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors) 137 { 138 struct gss_api_mech *mech; 139 struct xdr_netobj oid; 140 int i; 141 rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX; 142 143 for (i = 0; i < flavors->num_flavors; i++) { 144 struct nfs4_secinfo_flavor *flavor; 145 flavor = &flavors->flavors[i]; 146 147 if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) { 148 pseudoflavor = flavor->flavor; 149 break; 150 } else if (flavor->flavor == RPC_AUTH_GSS) { 151 oid.len = flavor->gss.sec_oid4.len; 152 oid.data = flavor->gss.sec_oid4.data; 153 mech = gss_mech_get_by_OID(&oid); 154 if (!mech) 155 continue; 156 pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service); 157 gss_mech_put(mech); 158 break; 159 } 160 } 161 162 return pseudoflavor; 163 } 164 165 static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name) 166 { 167 struct page *page; 168 struct nfs4_secinfo_flavors *flavors; 169 rpc_authflavor_t flavor; 170 int err; 171 172 page = alloc_page(GFP_KERNEL); 173 if (!page) 174 return -ENOMEM; 175 flavors = page_address(page); 176 177 err = nfs4_proc_secinfo(inode, name, flavors); 178 if (err < 0) { 179 flavor = err; 180 goto out; 181 } 182 183 flavor = nfs_find_best_sec(flavors); 184 185 out: 186 put_page(page); 187 return flavor; 188 } 189 190 /* 191 * Please call rpc_shutdown_client() when you are done with this client. 192 */ 193 struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode, 194 struct qstr *name) 195 { 196 rpc_authflavor_t flavor; 197 198 flavor = nfs4_negotiate_security(inode, name); 199 if ((int)flavor < 0) 200 return ERR_PTR((int)flavor); 201 202 return rpc_clone_client_set_auth(clnt, flavor); 203 } 204 205 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 206 char *page, char *page2, 207 const struct nfs4_fs_location *location) 208 { 209 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 210 struct vfsmount *mnt = ERR_PTR(-ENOENT); 211 char *mnt_path; 212 unsigned int maxbuflen; 213 unsigned int s; 214 215 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 216 if (IS_ERR(mnt_path)) 217 return ERR_CAST(mnt_path); 218 mountdata->mnt_path = mnt_path; 219 maxbuflen = mnt_path - 1 - page2; 220 221 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL); 222 if (mountdata->addr == NULL) 223 return ERR_PTR(-ENOMEM); 224 225 for (s = 0; s < location->nservers; s++) { 226 const struct nfs4_string *buf = &location->servers[s]; 227 228 if (buf->len <= 0 || buf->len >= maxbuflen) 229 continue; 230 231 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) 232 continue; 233 234 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len, 235 mountdata->addr, addr_bufsize, 236 NFS_SB(mountdata->sb)); 237 if (mountdata->addrlen == 0) 238 continue; 239 240 rpc_set_port(mountdata->addr, NFS_PORT); 241 242 memcpy(page2, buf->data, buf->len); 243 page2[buf->len] = '\0'; 244 mountdata->hostname = page2; 245 246 snprintf(page, PAGE_SIZE, "%s:%s", 247 mountdata->hostname, 248 mountdata->mnt_path); 249 250 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); 251 if (!IS_ERR(mnt)) 252 break; 253 } 254 kfree(mountdata->addr); 255 return mnt; 256 } 257 258 /** 259 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 260 * @dentry - parent directory 261 * @locations - array of NFSv4 server location information 262 * 263 */ 264 static struct vfsmount *nfs_follow_referral(struct dentry *dentry, 265 const struct nfs4_fs_locations *locations) 266 { 267 struct vfsmount *mnt = ERR_PTR(-ENOENT); 268 struct nfs_clone_mount mountdata = { 269 .sb = dentry->d_sb, 270 .dentry = dentry, 271 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor, 272 }; 273 char *page = NULL, *page2 = NULL; 274 int loc, error; 275 276 if (locations == NULL || locations->nlocations <= 0) 277 goto out; 278 279 dprintk("%s: referral at %s/%s\n", __func__, 280 dentry->d_parent->d_name.name, dentry->d_name.name); 281 282 page = (char *) __get_free_page(GFP_USER); 283 if (!page) 284 goto out; 285 286 page2 = (char *) __get_free_page(GFP_USER); 287 if (!page2) 288 goto out; 289 290 /* Ensure fs path is a prefix of current dentry path */ 291 error = nfs4_validate_fspath(dentry, locations, page, page2); 292 if (error < 0) { 293 mnt = ERR_PTR(error); 294 goto out; 295 } 296 297 for (loc = 0; loc < locations->nlocations; loc++) { 298 const struct nfs4_fs_location *location = &locations->locations[loc]; 299 300 if (location == NULL || location->nservers <= 0 || 301 location->rootpath.ncomponents == 0) 302 continue; 303 304 mnt = try_location(&mountdata, page, page2, location); 305 if (!IS_ERR(mnt)) 306 break; 307 } 308 309 out: 310 free_page((unsigned long) page); 311 free_page((unsigned long) page2); 312 dprintk("%s: done\n", __func__); 313 return mnt; 314 } 315 316 /* 317 * nfs_do_refmount - handle crossing a referral on server 318 * @dentry - dentry of referral 319 * 320 */ 321 static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry) 322 { 323 struct vfsmount *mnt = ERR_PTR(-ENOMEM); 324 struct dentry *parent; 325 struct nfs4_fs_locations *fs_locations = NULL; 326 struct page *page; 327 int err; 328 329 /* BUG_ON(IS_ROOT(dentry)); */ 330 dprintk("%s: enter\n", __func__); 331 332 page = alloc_page(GFP_KERNEL); 333 if (page == NULL) 334 goto out; 335 336 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 337 if (fs_locations == NULL) 338 goto out_free; 339 340 /* Get locations */ 341 mnt = ERR_PTR(-ENOENT); 342 343 parent = dget_parent(dentry); 344 dprintk("%s: getting locations for %s/%s\n", 345 __func__, parent->d_name.name, dentry->d_name.name); 346 347 err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page); 348 dput(parent); 349 if (err != 0 || 350 fs_locations->nlocations <= 0 || 351 fs_locations->fs_path.ncomponents <= 0) 352 goto out_free; 353 354 mnt = nfs_follow_referral(dentry, fs_locations); 355 out_free: 356 __free_page(page); 357 kfree(fs_locations); 358 out: 359 dprintk("%s: done\n", __func__); 360 return mnt; 361 } 362 363 struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry, 364 struct nfs_fh *fh, struct nfs_fattr *fattr) 365 { 366 struct dentry *parent = dget_parent(dentry); 367 struct rpc_clnt *client; 368 struct vfsmount *mnt; 369 370 /* Look it up again to get its attributes and sec flavor */ 371 client = nfs4_proc_lookup_mountpoint(parent->d_inode, &dentry->d_name, fh, fattr); 372 dput(parent); 373 if (IS_ERR(client)) 374 return ERR_CAST(client); 375 376 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) 377 mnt = nfs_do_refmount(client, dentry); 378 else 379 mnt = nfs_do_submount(dentry, fh, fattr, client->cl_auth->au_flavor); 380 381 rpc_shutdown_client(client); 382 return mnt; 383 } 384