/* * 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, const 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); const 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; }