diff options
Diffstat (limited to 'fs/nfs/nfs4namespace.c')
| -rw-r--r-- | fs/nfs/nfs4namespace.c | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c new file mode 100644 index 000000000..f59267237 --- /dev/null +++ b/fs/nfs/nfs4namespace.c @@ -0,0 +1,523 @@ +/* + * linux/fs/nfs/nfs4namespace.c + * + * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> + * - Modified by David Howells <dhowells@redhat.com> + * + * NFSv4 namespace + */ + +#include <linux/dcache.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/nfs_fs.h> +#include <linux/nfs_mount.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/sunrpc/clnt.h> +#include <linux/sunrpc/addr.h> +#include <linux/vfs.h> +#include <linux/inet.h> +#include "internal.h" +#include "nfs4_fs.h" +#include "dns_resolve.h" + +#define NFSDBG_FACILITY NFSDBG_VFS + +/* + * Convert the NFSv4 pathname components into a standard posix path. + * + * Note that the resulting string will be placed at the end of the buffer + */ +static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname, + char *buffer, ssize_t buflen) +{ + char *end = buffer + buflen; + int n; + + *--end = '\0'; + buflen--; + + n = pathname->ncomponents; + while (--n >= 0) { + const struct nfs4_string *component = &pathname->components[n]; + buflen -= component->len + 1; + if (buflen < 0) + goto Elong; + end -= component->len; + memcpy(end, component->data, component->len); + *--end = '/'; + } + return end; +Elong: + return ERR_PTR(-ENAMETOOLONG); +} + +/* + * return the path component of "<server>:<path>" + * nfspath - the "<server>:<path>" string + * end - one past the last char that could contain "<server>:" + * returns NULL on failure + */ +static char *nfs_path_component(const char *nfspath, const char *end) +{ + char *p; + + if (*nfspath == '[') { + /* parse [] escaped IPv6 addrs */ + p = strchr(nfspath, ']'); + if (p != NULL && ++p < end && *p == ':') + return p + 1; + } else { + /* otherwise split on first colon */ + p = strchr(nfspath, ':'); + if (p != NULL && p < end) + return p + 1; + } + return NULL; +} + +/* + * Determine the mount path as a string + */ +static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen) +{ + char *limit; + char *path = nfs_path(&limit, dentry, buffer, buflen, + NFS_PATH_CANONICAL); + if (!IS_ERR(path)) { + char *path_component = nfs_path_component(path, limit); + if (path_component) + return path_component; + } + return path; +} + +/* + * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we + * believe to be the server path to this dentry + */ +static int nfs4_validate_fspath(struct dentry *dentry, + const struct nfs4_fs_locations *locations, + char *page, char *page2) +{ + const char *path, *fs_path; + + path = nfs4_path(dentry, page, PAGE_SIZE); + if (IS_ERR(path)) + return PTR_ERR(path); + + fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); + if (IS_ERR(fs_path)) + return PTR_ERR(fs_path); + + if (strncmp(path, fs_path, strlen(fs_path)) != 0) { + dprintk("%s: path %s does not begin with fsroot %s\n", + __func__, path, fs_path); + return -ENOENT; + } + + return 0; +} + +static size_t nfs_parse_server_name(char *string, size_t len, + struct sockaddr *sa, size_t salen, struct net *net) +{ + ssize_t ret; + + ret = rpc_pton(net, string, len, sa, salen); + if (ret == 0) { + ret = nfs_dns_resolve_name(net, string, len, sa, salen); + if (ret < 0) + ret = 0; + } + return ret; +} + +/** + * nfs_find_best_sec - Find a security mechanism supported locally + * @server: NFS server struct + * @flavors: List of security tuples returned by SECINFO procedure + * + * Return an rpc client that uses the first security mechanism in + * "flavors" that is locally supported. The "flavors" array + * is searched in the order returned from the server, per RFC 3530 + * recommendation and each flavor is checked for membership in the + * sec= mount option list if it exists. + * + * Return -EPERM if no matching flavor is found in the array. + * + * Please call rpc_shutdown_client() when you are done with this rpc client. + * + */ +static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt, + struct nfs_server *server, + struct nfs4_secinfo_flavors *flavors) +{ + rpc_authflavor_t pflavor; + struct nfs4_secinfo4 *secinfo; + unsigned int i; + + for (i = 0; i < flavors->num_flavors; i++) { + secinfo = &flavors->flavors[i]; + + switch (secinfo->flavor) { + case RPC_AUTH_NULL: + case RPC_AUTH_UNIX: + case RPC_AUTH_GSS: + pflavor = rpcauth_get_pseudoflavor(secinfo->flavor, + &secinfo->flavor_info); + /* does the pseudoflavor match a sec= mount opt? */ + if (pflavor != RPC_AUTH_MAXFLAVOR && + nfs_auth_info_match(&server->auth_info, pflavor)) { + struct rpc_clnt *new; + struct rpc_cred *cred; + + /* Cloning creates an rpc_auth for the flavor */ + new = rpc_clone_client_set_auth(clnt, pflavor); + if (IS_ERR(new)) + continue; + /** + * Check that the user actually can use the + * flavor. This is mostly for RPC_AUTH_GSS + * where cr_init obtains a gss context + */ + cred = rpcauth_lookupcred(new->cl_auth, 0); + if (IS_ERR(cred)) { + rpc_shutdown_client(new); + continue; + } + put_rpccred(cred); + return new; + } + } + } + return ERR_PTR(-EPERM); +} + +/** + * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup, + * return an rpc_clnt that uses the best available security flavor with + * respect to the secinfo flavor list and the sec= mount options. + * + * @clnt: RPC client to clone + * @inode: directory inode + * @name: lookup name + * + * Please call rpc_shutdown_client() when you are done with this rpc client. + */ +struct rpc_clnt * +nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode, + struct qstr *name) +{ + struct page *page; + struct nfs4_secinfo_flavors *flavors; + struct rpc_clnt *new; + int err; + + page = alloc_page(GFP_KERNEL); + if (!page) + return ERR_PTR(-ENOMEM); + + flavors = page_address(page); + + err = nfs4_proc_secinfo(inode, name, flavors); + if (err < 0) { + new = ERR_PTR(err); + goto out; + } + + new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors); + +out: + put_page(page); + return new; +} + +static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, + char *page, char *page2, + const struct nfs4_fs_location *location) +{ + const size_t addr_bufsize = sizeof(struct sockaddr_storage); + struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client); + struct vfsmount *mnt = ERR_PTR(-ENOENT); + char *mnt_path; + unsigned int maxbuflen; + unsigned int s; + + mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); + if (IS_ERR(mnt_path)) + return ERR_CAST(mnt_path); + mountdata->mnt_path = mnt_path; + maxbuflen = mnt_path - 1 - page2; + + mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL); + if (mountdata->addr == NULL) + return ERR_PTR(-ENOMEM); + + for (s = 0; s < location->nservers; s++) { + const struct nfs4_string *buf = &location->servers[s]; + + if (buf->len <= 0 || buf->len >= maxbuflen) + continue; + + if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) + continue; + + mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len, + mountdata->addr, addr_bufsize, net); + if (mountdata->addrlen == 0) + continue; + + rpc_set_port(mountdata->addr, NFS_PORT); + + memcpy(page2, buf->data, buf->len); + page2[buf->len] = '\0'; + mountdata->hostname = page2; + + snprintf(page, PAGE_SIZE, "%s:%s", + mountdata->hostname, + mountdata->mnt_path); + + mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); + if (!IS_ERR(mnt)) + break; + } + kfree(mountdata->addr); + return mnt; +} + +/** + * nfs_follow_referral - set up mountpoint when hitting a referral on moved error + * @dentry - parent directory + * @locations - array of NFSv4 server location information + * + */ +static struct vfsmount *nfs_follow_referral(struct dentry *dentry, + const struct nfs4_fs_locations *locations) +{ + struct vfsmount *mnt = ERR_PTR(-ENOENT); + struct nfs_clone_mount mountdata = { + .sb = dentry->d_sb, + .dentry = dentry, + .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor, + }; + char *page = NULL, *page2 = NULL; + int loc, error; + + if (locations == NULL || locations->nlocations <= 0) + goto out; + + dprintk("%s: referral at %pd2\n", __func__, dentry); + + page = (char *) __get_free_page(GFP_USER); + if (!page) + goto out; + + page2 = (char *) __get_free_page(GFP_USER); + if (!page2) + goto out; + + /* Ensure fs path is a prefix of current dentry path */ + error = nfs4_validate_fspath(dentry, locations, page, page2); + if (error < 0) { + mnt = ERR_PTR(error); + goto out; + } + + for (loc = 0; loc < locations->nlocations; loc++) { + const struct nfs4_fs_location *location = &locations->locations[loc]; + + if (location == NULL || location->nservers <= 0 || + location->rootpath.ncomponents == 0) + continue; + + mnt = try_location(&mountdata, page, page2, location); + if (!IS_ERR(mnt)) + break; + } + +out: + free_page((unsigned long) page); + free_page((unsigned long) page2); + dprintk("%s: done\n", __func__); + return mnt; +} + +/* + * nfs_do_refmount - handle crossing a referral on server + * @dentry - dentry of referral + * + */ +static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry) +{ + struct vfsmount *mnt = ERR_PTR(-ENOMEM); + struct dentry *parent; + struct nfs4_fs_locations *fs_locations = NULL; + struct page *page; + int err; + + /* BUG_ON(IS_ROOT(dentry)); */ + dprintk("%s: enter\n", __func__); + + page = alloc_page(GFP_KERNEL); + if (page == NULL) + goto out; + + fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); + if (fs_locations == NULL) + goto out_free; + + /* Get locations */ + mnt = ERR_PTR(-ENOENT); + + parent = dget_parent(dentry); + dprintk("%s: getting locations for %pd2\n", + __func__, dentry); + + err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page); + dput(parent); + if (err != 0 || + fs_locations->nlocations <= 0 || + fs_locations->fs_path.ncomponents <= 0) + goto out_free; + + mnt = nfs_follow_referral(dentry, fs_locations); +out_free: + __free_page(page); + kfree(fs_locations); +out: + dprintk("%s: done\n", __func__); + return mnt; +} + +struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry, + struct nfs_fh *fh, struct nfs_fattr *fattr) +{ + rpc_authflavor_t flavor = server->client->cl_auth->au_flavor; + struct dentry *parent = dget_parent(dentry); + struct inode *dir = d_inode(parent); + struct qstr *name = &dentry->d_name; + struct rpc_clnt *client; + struct vfsmount *mnt; + + /* Look it up again to get its attributes and sec flavor */ + client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr); + dput(parent); + if (IS_ERR(client)) + return ERR_CAST(client); + + if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) { + mnt = nfs_do_refmount(client, dentry); + goto out; + } + + if (client->cl_auth->au_flavor != flavor) + flavor = client->cl_auth->au_flavor; + mnt = nfs_do_submount(dentry, fh, fattr, flavor); +out: + rpc_shutdown_client(client); + return mnt; +} + +/* + * Try one location from the fs_locations array. + * + * Returns zero on success, or a negative errno value. + */ +static int nfs4_try_replacing_one_location(struct nfs_server *server, + char *page, char *page2, + const struct nfs4_fs_location *location) +{ + const size_t addr_bufsize = sizeof(struct sockaddr_storage); + struct net *net = rpc_net_ns(server->client); + struct sockaddr *sap; + unsigned int s; + size_t salen; + int error; + + sap = kmalloc(addr_bufsize, GFP_KERNEL); + if (sap == NULL) + return -ENOMEM; + + error = -ENOENT; + for (s = 0; s < location->nservers; s++) { + const struct nfs4_string *buf = &location->servers[s]; + char *hostname; + + if (buf->len <= 0 || buf->len > PAGE_SIZE) + continue; + + if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL) + continue; + + salen = nfs_parse_server_name(buf->data, buf->len, + sap, addr_bufsize, net); + if (salen == 0) + continue; + rpc_set_port(sap, NFS_PORT); + + error = -ENOMEM; + hostname = kstrndup(buf->data, buf->len, GFP_KERNEL); + if (hostname == NULL) + break; + + error = nfs4_update_server(server, hostname, sap, salen, net); + kfree(hostname); + if (error == 0) + break; + } + + kfree(sap); + return error; +} + +/** + * nfs4_replace_transport - set up transport to destination server + * + * @server: export being migrated + * @locations: fs_locations array + * + * Returns zero on success, or a negative errno value. + * + * The client tries all the entries in the "locations" array, in the + * order returned by the server, until one works or the end of the + * array is reached. + */ +int nfs4_replace_transport(struct nfs_server *server, + const struct nfs4_fs_locations *locations) +{ + char *page = NULL, *page2 = NULL; + int loc, error; + + error = -ENOENT; + if (locations == NULL || locations->nlocations <= 0) + goto out; + + error = -ENOMEM; + page = (char *) __get_free_page(GFP_USER); + if (!page) + goto out; + page2 = (char *) __get_free_page(GFP_USER); + if (!page2) + goto out; + + for (loc = 0; loc < locations->nlocations; loc++) { + const struct nfs4_fs_location *location = + &locations->locations[loc]; + + if (location == NULL || location->nservers <= 0 || + location->rootpath.ncomponents == 0) + continue; + + error = nfs4_try_replacing_one_location(server, page, + page2, location); + if (error == 0) + break; + } + +out: + free_page((unsigned long)page); + free_page((unsigned long)page2); + return error; +} |