/* * 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/string.h> #include <linux/sunrpc/clnt.h> #include <linux/vfs.h> #include <linux/inet.h> #include "internal.h" #include "nfs4_fs.h" #define NFSDBG_FACILITY NFSDBG_VFS /* * Check if fs_root is valid */ 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); } /* * Determine the mount path as a string */ static char *nfs4_path(const struct vfsmount *mnt_parent, const struct dentry *dentry, char *buffer, ssize_t buflen) { const char *srvpath; srvpath = strchr(mnt_parent->mnt_devname, ':'); if (srvpath) srvpath++; else srvpath = mnt_parent->mnt_devname; return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen); } /* * 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(const struct vfsmount *mnt_parent, const struct dentry *dentry, const struct nfs4_fs_locations *locations, char *page, char *page2) { const char *path, *fs_path; path = nfs4_path(mnt_parent, 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; } /* * Check if the string represents a "valid" IPv4 address */ static inline int valid_ipaddr4(const char *buf) { int rc, count, in[4]; rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]); if (rc != 4) return -EINVAL; for (count = 0; count < 4; count++) { if (in[count] > 255) return -EINVAL; } return 0; } /** * nfs_follow_referral - set up mountpoint when hitting a referral on moved error * @mnt_parent - mountpoint of parent directory * @dentry - parent directory * @locations - array of NFSv4 server location information * */ static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, const struct dentry *dentry, const struct nfs4_fs_locations *locations) { struct vfsmount *mnt = ERR_PTR(-ENOENT); struct nfs_clone_mount mountdata = { .sb = mnt_parent->mnt_sb, .dentry = dentry, .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor, }; char *page = NULL, *page2 = NULL; unsigned int s; int loc, error; if (locations == NULL || locations->nlocations <= 0) goto out; dprintk("%s: referral at %s/%s\n", __func__, dentry->d_parent->d_name.name, dentry->d_name.name); 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(mnt_parent, dentry, locations, page, page2); if (error < 0) { mnt = ERR_PTR(error); goto out; } loc = 0; while (loc < locations->nlocations && IS_ERR(mnt)) { const struct nfs4_fs_location *location = &locations->locations[loc]; char *mnt_path; if (location == NULL || location->nservers <= 0 || location->rootpath.ncomponents == 0) { loc++; continue; } mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); if (IS_ERR(mnt_path)) { loc++; continue; } mountdata.mnt_path = mnt_path; s = 0; while (s < location->nservers) { struct sockaddr_in addr = { .sin_family = AF_INET, .sin_port = htons(NFS_PORT), }; if (location->servers[s].len <= 0 || valid_ipaddr4(location->servers[s].data) < 0) { s++; continue; } mountdata.hostname = location->servers[s].data; addr.sin_addr.s_addr = in_aton(mountdata.hostname), mountdata.addr = (struct sockaddr *)&addr; mountdata.addrlen = sizeof(addr); 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; } s++; } loc++; } 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 * @nd - nameidata info * */ struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, 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 %s/%s\n", __func__, parent->d_name.name, dentry->d_name.name); err = nfs4_proc_fs_locations(parent->d_inode, &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(mnt_parent, dentry, fs_locations); out_free: __free_page(page); kfree(fs_locations); out: dprintk("%s: done\n", __func__); return mnt; }