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 * Determine the mount path as a string 56 */ 57 static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen) 58 { 59 char *limit; 60 char *path = nfs_path(&limit, dentry, buffer, buflen); 61 if (!IS_ERR(path)) { 62 char *colon = strchr(path, ':'); 63 if (colon && colon < limit) 64 path = colon + 1; 65 } 66 return path; 67 } 68 69 /* 70 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we 71 * believe to be the server path to this dentry 72 */ 73 static int nfs4_validate_fspath(struct dentry *dentry, 74 const struct nfs4_fs_locations *locations, 75 char *page, char *page2) 76 { 77 const char *path, *fs_path; 78 79 path = nfs4_path(dentry, page, PAGE_SIZE); 80 if (IS_ERR(path)) 81 return PTR_ERR(path); 82 83 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); 84 if (IS_ERR(fs_path)) 85 return PTR_ERR(fs_path); 86 87 if (strncmp(path, fs_path, strlen(fs_path)) != 0) { 88 dprintk("%s: path %s does not begin with fsroot %s\n", 89 __func__, path, fs_path); 90 return -ENOENT; 91 } 92 93 return 0; 94 } 95 96 static size_t nfs_parse_server_name(char *string, size_t len, 97 struct sockaddr *sa, size_t salen, struct nfs_server *server) 98 { 99 struct net *net = rpc_net_ns(server->client); 100 ssize_t ret; 101 102 ret = rpc_pton(net, string, len, sa, salen); 103 if (ret == 0) { 104 ret = nfs_dns_resolve_name(net, string, len, sa, salen); 105 if (ret < 0) 106 ret = 0; 107 } 108 return ret; 109 } 110 111 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 112 char *page, char *page2, 113 const struct nfs4_fs_location *location) 114 { 115 const size_t addr_bufsize = sizeof(struct sockaddr_storage); 116 struct vfsmount *mnt = ERR_PTR(-ENOENT); 117 char *mnt_path; 118 unsigned int maxbuflen; 119 unsigned int s; 120 121 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 122 if (IS_ERR(mnt_path)) 123 return ERR_CAST(mnt_path); 124 mountdata->mnt_path = mnt_path; 125 maxbuflen = mnt_path - 1 - page2; 126 127 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL); 128 if (mountdata->addr == NULL) 129 return ERR_PTR(-ENOMEM); 130 131 for (s = 0; s < location->nservers; s++) { 132 const struct nfs4_string *buf = &location->servers[s]; 133 134 if (buf->len <= 0 || buf->len >= maxbuflen) 135 continue; 136 137 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) 138 continue; 139 140 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len, 141 mountdata->addr, addr_bufsize, 142 NFS_SB(mountdata->sb)); 143 if (mountdata->addrlen == 0) 144 continue; 145 146 rpc_set_port(mountdata->addr, NFS_PORT); 147 148 memcpy(page2, buf->data, buf->len); 149 page2[buf->len] = '\0'; 150 mountdata->hostname = page2; 151 152 snprintf(page, PAGE_SIZE, "%s:%s", 153 mountdata->hostname, 154 mountdata->mnt_path); 155 156 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); 157 if (!IS_ERR(mnt)) 158 break; 159 } 160 kfree(mountdata->addr); 161 return mnt; 162 } 163 164 /** 165 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 166 * @dentry - parent directory 167 * @locations - array of NFSv4 server location information 168 * 169 */ 170 static struct vfsmount *nfs_follow_referral(struct dentry *dentry, 171 const struct nfs4_fs_locations *locations) 172 { 173 struct vfsmount *mnt = ERR_PTR(-ENOENT); 174 struct nfs_clone_mount mountdata = { 175 .sb = dentry->d_sb, 176 .dentry = dentry, 177 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor, 178 }; 179 char *page = NULL, *page2 = NULL; 180 int loc, error; 181 182 if (locations == NULL || locations->nlocations <= 0) 183 goto out; 184 185 dprintk("%s: referral at %s/%s\n", __func__, 186 dentry->d_parent->d_name.name, dentry->d_name.name); 187 188 page = (char *) __get_free_page(GFP_USER); 189 if (!page) 190 goto out; 191 192 page2 = (char *) __get_free_page(GFP_USER); 193 if (!page2) 194 goto out; 195 196 /* Ensure fs path is a prefix of current dentry path */ 197 error = nfs4_validate_fspath(dentry, locations, page, page2); 198 if (error < 0) { 199 mnt = ERR_PTR(error); 200 goto out; 201 } 202 203 for (loc = 0; loc < locations->nlocations; loc++) { 204 const struct nfs4_fs_location *location = &locations->locations[loc]; 205 206 if (location == NULL || location->nservers <= 0 || 207 location->rootpath.ncomponents == 0) 208 continue; 209 210 mnt = try_location(&mountdata, page, page2, location); 211 if (!IS_ERR(mnt)) 212 break; 213 } 214 215 out: 216 free_page((unsigned long) page); 217 free_page((unsigned long) page2); 218 dprintk("%s: done\n", __func__); 219 return mnt; 220 } 221 222 /* 223 * nfs_do_refmount - handle crossing a referral on server 224 * @dentry - dentry of referral 225 * 226 */ 227 struct vfsmount *nfs_do_refmount(struct dentry *dentry) 228 { 229 struct vfsmount *mnt = ERR_PTR(-ENOMEM); 230 struct dentry *parent; 231 struct nfs4_fs_locations *fs_locations = NULL; 232 struct page *page; 233 int err; 234 235 /* BUG_ON(IS_ROOT(dentry)); */ 236 dprintk("%s: enter\n", __func__); 237 238 page = alloc_page(GFP_KERNEL); 239 if (page == NULL) 240 goto out; 241 242 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 243 if (fs_locations == NULL) 244 goto out_free; 245 246 /* Get locations */ 247 mnt = ERR_PTR(-ENOENT); 248 249 parent = dget_parent(dentry); 250 dprintk("%s: getting locations for %s/%s\n", 251 __func__, parent->d_name.name, dentry->d_name.name); 252 253 err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page); 254 dput(parent); 255 if (err != 0 || 256 fs_locations->nlocations <= 0 || 257 fs_locations->fs_path.ncomponents <= 0) 258 goto out_free; 259 260 mnt = nfs_follow_referral(dentry, fs_locations); 261 out_free: 262 __free_page(page); 263 kfree(fs_locations); 264 out: 265 dprintk("%s: done\n", __func__); 266 return mnt; 267 } 268