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