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 21 #define NFSDBG_FACILITY NFSDBG_VFS 22 23 /* 24 * Check if fs_root is valid 25 */ 26 static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname, 27 char *buffer, ssize_t buflen) 28 { 29 char *end = buffer + buflen; 30 int n; 31 32 *--end = '\0'; 33 buflen--; 34 35 n = pathname->ncomponents; 36 while (--n >= 0) { 37 const struct nfs4_string *component = &pathname->components[n]; 38 buflen -= component->len + 1; 39 if (buflen < 0) 40 goto Elong; 41 end -= component->len; 42 memcpy(end, component->data, component->len); 43 *--end = '/'; 44 } 45 return end; 46 Elong: 47 return ERR_PTR(-ENAMETOOLONG); 48 } 49 50 /* 51 * Determine the mount path as a string 52 */ 53 static char *nfs4_path(const struct vfsmount *mnt_parent, 54 const struct dentry *dentry, 55 char *buffer, ssize_t buflen) 56 { 57 const char *srvpath; 58 59 srvpath = strchr(mnt_parent->mnt_devname, ':'); 60 if (srvpath) 61 srvpath++; 62 else 63 srvpath = mnt_parent->mnt_devname; 64 65 return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen); 66 } 67 68 /* 69 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we 70 * believe to be the server path to this dentry 71 */ 72 static int nfs4_validate_fspath(const struct vfsmount *mnt_parent, 73 const 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(mnt_parent, 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 __FUNCTION__, path, fs_path); 90 return -ENOENT; 91 } 92 93 return 0; 94 } 95 96 /* 97 * Check if the string represents a "valid" IPv4 address 98 */ 99 static inline int valid_ipaddr4(const char *buf) 100 { 101 int rc, count, in[4]; 102 103 rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]); 104 if (rc != 4) 105 return -EINVAL; 106 for (count = 0; count < 4; count++) { 107 if (in[count] > 255) 108 return -EINVAL; 109 } 110 return 0; 111 } 112 113 /** 114 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 115 * @mnt_parent - mountpoint of parent directory 116 * @dentry - parent directory 117 * @fspath - fs path returned in fs_locations 118 * @mntpath - mount path to new server 119 * @hostname - hostname of new server 120 * @addr - host addr of new server 121 * 122 */ 123 static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, 124 const struct dentry *dentry, 125 const struct nfs4_fs_locations *locations) 126 { 127 struct vfsmount *mnt = ERR_PTR(-ENOENT); 128 struct nfs_clone_mount mountdata = { 129 .sb = mnt_parent->mnt_sb, 130 .dentry = dentry, 131 .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor, 132 }; 133 char *page = NULL, *page2 = NULL; 134 int loc, s, error; 135 136 if (locations == NULL || locations->nlocations <= 0) 137 goto out; 138 139 dprintk("%s: referral at %s/%s\n", __FUNCTION__, 140 dentry->d_parent->d_name.name, dentry->d_name.name); 141 142 page = (char *) __get_free_page(GFP_USER); 143 if (!page) 144 goto out; 145 146 page2 = (char *) __get_free_page(GFP_USER); 147 if (!page2) 148 goto out; 149 150 /* Ensure fs path is a prefix of current dentry path */ 151 error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2); 152 if (error < 0) { 153 mnt = ERR_PTR(error); 154 goto out; 155 } 156 157 loc = 0; 158 while (loc < locations->nlocations && IS_ERR(mnt)) { 159 const struct nfs4_fs_location *location = &locations->locations[loc]; 160 char *mnt_path; 161 162 if (location == NULL || location->nservers <= 0 || 163 location->rootpath.ncomponents == 0) { 164 loc++; 165 continue; 166 } 167 168 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 169 if (IS_ERR(mnt_path)) { 170 loc++; 171 continue; 172 } 173 mountdata.mnt_path = mnt_path; 174 175 s = 0; 176 while (s < location->nservers) { 177 struct sockaddr_in addr = {}; 178 179 if (location->servers[s].len <= 0 || 180 valid_ipaddr4(location->servers[s].data) < 0) { 181 s++; 182 continue; 183 } 184 185 mountdata.hostname = location->servers[s].data; 186 addr.sin_addr.s_addr = in_aton(mountdata.hostname); 187 addr.sin_family = AF_INET; 188 addr.sin_port = htons(NFS_PORT); 189 mountdata.addr = &addr; 190 191 snprintf(page, PAGE_SIZE, "%s:%s", 192 mountdata.hostname, 193 mountdata.mnt_path); 194 195 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, &mountdata); 196 if (!IS_ERR(mnt)) { 197 break; 198 } 199 s++; 200 } 201 loc++; 202 } 203 204 out: 205 free_page((unsigned long) page); 206 free_page((unsigned long) page2); 207 dprintk("%s: done\n", __FUNCTION__); 208 return mnt; 209 } 210 211 /* 212 * nfs_do_refmount - handle crossing a referral on server 213 * @dentry - dentry of referral 214 * @nd - nameidata info 215 * 216 */ 217 struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry) 218 { 219 struct vfsmount *mnt = ERR_PTR(-ENOMEM); 220 struct dentry *parent; 221 struct nfs4_fs_locations *fs_locations = NULL; 222 struct page *page; 223 int err; 224 225 /* BUG_ON(IS_ROOT(dentry)); */ 226 dprintk("%s: enter\n", __FUNCTION__); 227 228 page = alloc_page(GFP_KERNEL); 229 if (page == NULL) 230 goto out; 231 232 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 233 if (fs_locations == NULL) 234 goto out_free; 235 236 /* Get locations */ 237 mnt = ERR_PTR(-ENOENT); 238 239 parent = dget_parent(dentry); 240 dprintk("%s: getting locations for %s/%s\n", 241 __FUNCTION__, parent->d_name.name, dentry->d_name.name); 242 243 err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page); 244 dput(parent); 245 if (err != 0 || 246 fs_locations->nlocations <= 0 || 247 fs_locations->fs_path.ncomponents <= 0) 248 goto out_free; 249 250 mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations); 251 out_free: 252 __free_page(page); 253 kfree(fs_locations); 254 out: 255 dprintk("%s: done\n", __FUNCTION__); 256 return mnt; 257 } 258