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/string.h> 15 #include <linux/sunrpc/clnt.h> 16 #include <linux/vfs.h> 17 #include <linux/inet.h> 18 #include "internal.h" 19 #include "nfs4_fs.h" 20 #include "dns_resolve.h" 21 22 #define NFSDBG_FACILITY NFSDBG_VFS 23 24 /* 25 * Convert the NFSv4 pathname components into a standard posix path. 26 * 27 * Note that the resulting string will be placed at the end of the buffer 28 */ 29 static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname, 30 char *buffer, ssize_t buflen) 31 { 32 char *end = buffer + buflen; 33 int n; 34 35 *--end = '\0'; 36 buflen--; 37 38 n = pathname->ncomponents; 39 while (--n >= 0) { 40 const struct nfs4_string *component = &pathname->components[n]; 41 buflen -= component->len + 1; 42 if (buflen < 0) 43 goto Elong; 44 end -= component->len; 45 memcpy(end, component->data, component->len); 46 *--end = '/'; 47 } 48 return end; 49 Elong: 50 return ERR_PTR(-ENAMETOOLONG); 51 } 52 53 /* 54 * Determine the mount path as a string 55 */ 56 static char *nfs4_path(const struct vfsmount *mnt_parent, 57 const struct dentry *dentry, 58 char *buffer, ssize_t buflen) 59 { 60 const char *srvpath; 61 62 srvpath = strchr(mnt_parent->mnt_devname, ':'); 63 if (srvpath) 64 srvpath++; 65 else 66 srvpath = mnt_parent->mnt_devname; 67 68 return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen); 69 } 70 71 /* 72 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we 73 * believe to be the server path to this dentry 74 */ 75 static int nfs4_validate_fspath(const struct vfsmount *mnt_parent, 76 const struct dentry *dentry, 77 const struct nfs4_fs_locations *locations, 78 char *page, char *page2) 79 { 80 const char *path, *fs_path; 81 82 path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE); 83 if (IS_ERR(path)) 84 return PTR_ERR(path); 85 86 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); 87 if (IS_ERR(fs_path)) 88 return PTR_ERR(fs_path); 89 90 if (strncmp(path, fs_path, strlen(fs_path)) != 0) { 91 dprintk("%s: path %s does not begin with fsroot %s\n", 92 __func__, path, fs_path); 93 return -ENOENT; 94 } 95 96 return 0; 97 } 98 99 static size_t nfs_parse_server_name(char *string, size_t len, 100 struct sockaddr *sa, size_t salen) 101 { 102 ssize_t ret; 103 104 ret = rpc_pton(string, len, sa, salen); 105 if (ret == 0) { 106 ret = nfs_dns_resolve_name(string, len, sa, salen); 107 if (ret < 0) 108 ret = 0; 109 } 110 return ret; 111 } 112 113 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 114 char *page, char *page2, 115 const struct nfs4_fs_location *location) 116 { 117 struct vfsmount *mnt = ERR_PTR(-ENOENT); 118 char *mnt_path; 119 unsigned int maxbuflen; 120 unsigned int s; 121 122 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 123 if (IS_ERR(mnt_path)) 124 return ERR_CAST(mnt_path); 125 mountdata->mnt_path = mnt_path; 126 maxbuflen = mnt_path - 1 - page2; 127 128 for (s = 0; s < location->nservers; s++) { 129 const struct nfs4_string *buf = &location->servers[s]; 130 struct sockaddr_storage addr; 131 132 if (buf->len <= 0 || buf->len >= maxbuflen) 133 continue; 134 135 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) 136 continue; 137 138 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len, 139 (struct sockaddr *)&addr, sizeof(addr)); 140 if (mountdata->addrlen == 0) 141 continue; 142 143 mountdata->addr = (struct sockaddr *)&addr; 144 rpc_set_port(mountdata->addr, NFS_PORT); 145 146 memcpy(page2, buf->data, buf->len); 147 page2[buf->len] = '\0'; 148 mountdata->hostname = page2; 149 150 snprintf(page, PAGE_SIZE, "%s:%s", 151 mountdata->hostname, 152 mountdata->mnt_path); 153 154 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); 155 if (!IS_ERR(mnt)) 156 break; 157 } 158 return mnt; 159 } 160 161 /** 162 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 163 * @mnt_parent - mountpoint of parent directory 164 * @dentry - parent directory 165 * @locations - array of NFSv4 server location information 166 * 167 */ 168 static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, 169 const struct dentry *dentry, 170 const struct nfs4_fs_locations *locations) 171 { 172 struct vfsmount *mnt = ERR_PTR(-ENOENT); 173 struct nfs_clone_mount mountdata = { 174 .sb = mnt_parent->mnt_sb, 175 .dentry = dentry, 176 .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor, 177 }; 178 char *page = NULL, *page2 = NULL; 179 int loc, error; 180 181 if (locations == NULL || locations->nlocations <= 0) 182 goto out; 183 184 dprintk("%s: referral at %s/%s\n", __func__, 185 dentry->d_parent->d_name.name, dentry->d_name.name); 186 187 page = (char *) __get_free_page(GFP_USER); 188 if (!page) 189 goto out; 190 191 page2 = (char *) __get_free_page(GFP_USER); 192 if (!page2) 193 goto out; 194 195 /* Ensure fs path is a prefix of current dentry path */ 196 error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2); 197 if (error < 0) { 198 mnt = ERR_PTR(error); 199 goto out; 200 } 201 202 for (loc = 0; loc < locations->nlocations; loc++) { 203 const struct nfs4_fs_location *location = &locations->locations[loc]; 204 205 if (location == NULL || location->nservers <= 0 || 206 location->rootpath.ncomponents == 0) 207 continue; 208 209 mnt = try_location(&mountdata, page, page2, location); 210 if (!IS_ERR(mnt)) 211 break; 212 } 213 214 out: 215 free_page((unsigned long) page); 216 free_page((unsigned long) page2); 217 dprintk("%s: done\n", __func__); 218 return mnt; 219 } 220 221 /* 222 * nfs_do_refmount - handle crossing a referral on server 223 * @dentry - dentry of referral 224 * @nd - nameidata info 225 * 226 */ 227 struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, 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(mnt_parent, 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