1 // SPDX-License-Identifier: GPL-2.0
3 * linux/fs/nfs/nfs4namespace.c
5 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
6 * - Modified by David Howells <dhowells@redhat.com>
11 #include <linux/module.h>
12 #include <linux/dcache.h>
13 #include <linux/mount.h>
14 #include <linux/namei.h>
15 #include <linux/nfs_fs.h>
16 #include <linux/nfs_mount.h>
17 #include <linux/slab.h>
18 #include <linux/string.h>
19 #include <linux/sunrpc/clnt.h>
20 #include <linux/sunrpc/addr.h>
21 #include <linux/vfs.h>
22 #include <linux/inet.h>
26 #include "dns_resolve.h"
28 #define NFSDBG_FACILITY NFSDBG_VFS
31 * Work out the length that an NFSv4 path would render to as a standard posix
32 * path, with a leading slash but no terminating slash.
34 static ssize_t nfs4_pathname_len(const struct nfs4_pathname *pathname)
39 for (i = 0; i < pathname->ncomponents; i++) {
40 const struct nfs4_string *component = &pathname->components[i];
42 if (component->len > NAME_MAX)
44 len += 1 + component->len; /* Adding "/foo" */
55 * Convert the NFSv4 pathname components into a standard posix path.
57 static char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
64 len = nfs4_pathname_len(pathname);
69 p = buf = kmalloc(len + 1, GFP_KERNEL);
71 return ERR_PTR(-ENOMEM);
73 for (i = 0; i < pathname->ncomponents; i++) {
74 const struct nfs4_string *component = &pathname->components[i];
77 memcpy(p, component->data, component->len);
86 * return the path component of "<server>:<path>"
87 * nfspath - the "<server>:<path>" string
88 * end - one past the last char that could contain "<server>:"
89 * returns NULL on failure
91 static char *nfs_path_component(const char *nfspath, const char *end)
95 if (*nfspath == '[') {
96 /* parse [] escaped IPv6 addrs */
97 p = strchr(nfspath, ']');
98 if (p != NULL && ++p < end && *p == ':')
101 /* otherwise split on first colon */
102 p = strchr(nfspath, ':');
103 if (p != NULL && p < end)
110 * Determine the mount path as a string
112 static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
115 char *path = nfs_path(&limit, dentry, buffer, buflen,
118 char *path_component = nfs_path_component(path, limit);
120 return path_component;
126 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
127 * believe to be the server path to this dentry
129 static int nfs4_validate_fspath(struct dentry *dentry,
130 const struct nfs4_fs_locations *locations,
131 struct nfs_fs_context *ctx)
139 buf = kmalloc(4096, GFP_KERNEL);
140 path = nfs4_path(dentry, buf, 4096);
143 return PTR_ERR(path);
146 fs_path = nfs4_pathname_string(&locations->fs_path, &len);
147 if (IS_ERR(fs_path)) {
149 return PTR_ERR(fs_path);
152 n = strncmp(path, fs_path, len);
156 dprintk("%s: path %s does not begin with fsroot %s\n",
157 __func__, path, ctx->nfs_server.export_path);
164 static size_t nfs_parse_server_name(char *string, size_t len,
165 struct sockaddr *sa, size_t salen, struct net *net)
169 ret = rpc_pton(net, string, len, sa, salen);
171 ret = nfs_dns_resolve_name(net, string, len, sa, salen);
179 * nfs_find_best_sec - Find a security mechanism supported locally
180 * @clnt: pointer to rpc_clnt
181 * @server: NFS server struct
182 * @flavors: List of security tuples returned by SECINFO procedure
184 * Return an rpc client that uses the first security mechanism in
185 * "flavors" that is locally supported. The "flavors" array
186 * is searched in the order returned from the server, per RFC 3530
187 * recommendation and each flavor is checked for membership in the
188 * sec= mount option list if it exists.
190 * Return -EPERM if no matching flavor is found in the array.
192 * Please call rpc_shutdown_client() when you are done with this rpc client.
195 static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
196 struct nfs_server *server,
197 struct nfs4_secinfo_flavors *flavors)
199 rpc_authflavor_t pflavor;
200 struct nfs4_secinfo4 *secinfo;
203 for (i = 0; i < flavors->num_flavors; i++) {
204 secinfo = &flavors->flavors[i];
206 switch (secinfo->flavor) {
210 pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
211 &secinfo->flavor_info);
212 /* does the pseudoflavor match a sec= mount opt? */
213 if (pflavor != RPC_AUTH_MAXFLAVOR &&
214 nfs_auth_info_match(&server->auth_info, pflavor)) {
215 struct rpc_clnt *new;
216 struct rpc_cred *cred;
218 /* Cloning creates an rpc_auth for the flavor */
219 new = rpc_clone_client_set_auth(clnt, pflavor);
223 * Check that the user actually can use the
224 * flavor. This is mostly for RPC_AUTH_GSS
225 * where cr_init obtains a gss context
227 cred = rpcauth_lookupcred(new->cl_auth, 0);
229 rpc_shutdown_client(new);
237 return ERR_PTR(-EPERM);
241 * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
242 * return an rpc_clnt that uses the best available security flavor with
243 * respect to the secinfo flavor list and the sec= mount options.
245 * @clnt: RPC client to clone
246 * @inode: directory inode
249 * Please call rpc_shutdown_client() when you are done with this rpc client.
252 nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
253 const struct qstr *name)
256 struct nfs4_secinfo_flavors *flavors;
257 struct rpc_clnt *new;
260 page = alloc_page(GFP_KERNEL);
262 return ERR_PTR(-ENOMEM);
264 flavors = page_address(page);
266 err = nfs4_proc_secinfo(inode, name, flavors);
272 new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
279 static int try_location(struct fs_context *fc,
280 const struct nfs4_fs_location *location)
282 struct nfs_fs_context *ctx = nfs_fc2context(fc);
284 char *export_path, *source, *p;
287 /* Allocate a buffer big enough to hold any of the hostnames plus a
288 * terminating char and also a buffer big enough to hold the hostname
289 * plus a colon plus the path.
292 for (s = 0; s < location->nservers; s++) {
293 const struct nfs4_string *buf = &location->servers[s];
298 kfree(ctx->nfs_server.hostname);
299 ctx->nfs_server.hostname = kmalloc(len + 1, GFP_KERNEL);
300 if (!ctx->nfs_server.hostname)
303 export_path = nfs4_pathname_string(&location->rootpath,
304 &ctx->nfs_server.export_path_len);
305 if (IS_ERR(export_path))
306 return PTR_ERR(export_path);
308 ctx->nfs_server.export_path = export_path;
310 source = kmalloc(len + 1 + ctx->nfs_server.export_path_len + 1,
317 for (s = 0; s < location->nservers; s++) {
318 const struct nfs4_string *buf = &location->servers[s];
320 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
323 ctx->nfs_server.addrlen =
324 nfs_parse_server_name(buf->data, buf->len,
325 &ctx->nfs_server.address,
326 sizeof(ctx->nfs_server._address),
328 if (ctx->nfs_server.addrlen == 0)
331 rpc_set_port(&ctx->nfs_server.address, NFS_PORT);
333 memcpy(ctx->nfs_server.hostname, buf->data, buf->len);
334 ctx->nfs_server.hostname[buf->len] = '\0';
337 memcpy(p, buf->data, buf->len);
340 memcpy(p, ctx->nfs_server.export_path, ctx->nfs_server.export_path_len);
341 p += ctx->nfs_server.export_path_len;
344 ret = nfs4_get_referral_tree(fc);
353 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
354 * @dentry: parent directory
355 * @locations: array of NFSv4 server location information
358 static int nfs_follow_referral(struct fs_context *fc,
359 const struct nfs4_fs_locations *locations)
361 struct nfs_fs_context *ctx = nfs_fc2context(fc);
364 if (locations == NULL || locations->nlocations <= 0)
367 dprintk("%s: referral at %pd2\n", __func__, ctx->clone_data.dentry);
369 /* Ensure fs path is a prefix of current dentry path */
370 error = nfs4_validate_fspath(ctx->clone_data.dentry, locations, ctx);
375 for (loc = 0; loc < locations->nlocations; loc++) {
376 const struct nfs4_fs_location *location = &locations->locations[loc];
378 if (location == NULL || location->nservers <= 0 ||
379 location->rootpath.ncomponents == 0)
382 error = try_location(fc, location);
391 * nfs_do_refmount - handle crossing a referral on server
392 * @dentry - dentry of referral
395 static int nfs_do_refmount(struct fs_context *fc, struct rpc_clnt *client)
397 struct nfs_fs_context *ctx = nfs_fc2context(fc);
398 struct dentry *dentry, *parent;
399 struct nfs4_fs_locations *fs_locations = NULL;
403 /* BUG_ON(IS_ROOT(dentry)); */
404 page = alloc_page(GFP_KERNEL);
408 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
413 dentry = ctx->clone_data.dentry;
414 parent = dget_parent(dentry);
415 dprintk("%s: getting locations for %pd2\n",
418 err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page);
424 if (fs_locations->nlocations <= 0 ||
425 fs_locations->fs_path.ncomponents <= 0)
428 err = nfs_follow_referral(fc, fs_locations);
436 int nfs4_submount(struct fs_context *fc, struct nfs_server *server)
438 struct nfs_fs_context *ctx = nfs_fc2context(fc);
439 struct dentry *dentry = ctx->clone_data.dentry;
440 struct dentry *parent = dget_parent(dentry);
441 struct inode *dir = d_inode(parent);
442 const struct qstr *name = &dentry->d_name;
443 struct rpc_clnt *client;
446 /* Look it up again to get its attributes and sec flavor */
447 client = nfs4_proc_lookup_mountpoint(dir, name, ctx->mntfh,
448 ctx->clone_data.fattr);
451 return PTR_ERR(client);
453 ctx->selected_flavor = client->cl_auth->au_flavor;
454 if (ctx->clone_data.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
455 ret = nfs_do_refmount(fc, client);
457 ret = nfs_do_submount(fc);
460 rpc_shutdown_client(client);
465 * Try one location from the fs_locations array.
467 * Returns zero on success, or a negative errno value.
469 static int nfs4_try_replacing_one_location(struct nfs_server *server,
470 char *page, char *page2,
471 const struct nfs4_fs_location *location)
473 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
474 struct net *net = rpc_net_ns(server->client);
475 struct sockaddr *sap;
480 sap = kmalloc(addr_bufsize, GFP_KERNEL);
485 for (s = 0; s < location->nservers; s++) {
486 const struct nfs4_string *buf = &location->servers[s];
489 if (buf->len <= 0 || buf->len > PAGE_SIZE)
492 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
495 salen = nfs_parse_server_name(buf->data, buf->len,
496 sap, addr_bufsize, net);
499 rpc_set_port(sap, NFS_PORT);
502 hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
503 if (hostname == NULL)
506 error = nfs4_update_server(server, hostname, sap, salen, net);
517 * nfs4_replace_transport - set up transport to destination server
519 * @server: export being migrated
520 * @locations: fs_locations array
522 * Returns zero on success, or a negative errno value.
524 * The client tries all the entries in the "locations" array, in the
525 * order returned by the server, until one works or the end of the
528 int nfs4_replace_transport(struct nfs_server *server,
529 const struct nfs4_fs_locations *locations)
531 char *page = NULL, *page2 = NULL;
535 if (locations == NULL || locations->nlocations <= 0)
539 page = (char *) __get_free_page(GFP_USER);
542 page2 = (char *) __get_free_page(GFP_USER);
546 for (loc = 0; loc < locations->nlocations; loc++) {
547 const struct nfs4_fs_location *location =
548 &locations->locations[loc];
550 if (location == NULL || location->nservers <= 0 ||
551 location->rootpath.ncomponents == 0)
554 error = nfs4_try_replacing_one_location(server, page,
561 free_page((unsigned long)page);
562 free_page((unsigned long)page2);