1 /* 2 * linux/fs/nfsd/nfs4recover.c 3 * 4 * Copyright (c) 2004 The Regents of the University of Michigan. 5 * All rights reserved. 6 * 7 * Andy Adamson <andros@citi.umich.edu> 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its 19 * contributors may be used to endorse or promote products derived 20 * from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 25 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 29 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 30 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 31 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 32 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 * 34 */ 35 36 #include <linux/err.h> 37 #include <linux/sunrpc/svc.h> 38 #include <linux/nfsd/nfsd.h> 39 #include <linux/nfs4.h> 40 #include <linux/nfsd/state.h> 41 #include <linux/nfsd/xdr4.h> 42 #include <linux/param.h> 43 #include <linux/file.h> 44 #include <linux/namei.h> 45 #include <asm/uaccess.h> 46 #include <linux/scatterlist.h> 47 #include <linux/crypto.h> 48 #include <linux/sched.h> 49 #include <linux/mount.h> 50 51 #define NFSDDBG_FACILITY NFSDDBG_PROC 52 53 /* Globals */ 54 static struct path rec_dir; 55 static int rec_dir_init = 0; 56 57 static int 58 nfs4_save_creds(const struct cred **original_creds) 59 { 60 struct cred *new; 61 62 new = prepare_creds(); 63 if (!new) 64 return -ENOMEM; 65 66 new->fsuid = 0; 67 new->fsgid = 0; 68 *original_creds = override_creds(new); 69 put_cred(new); 70 return 0; 71 } 72 73 static void 74 nfs4_reset_creds(const struct cred *original) 75 { 76 revert_creds(original); 77 } 78 79 static void 80 md5_to_hex(char *out, char *md5) 81 { 82 int i; 83 84 for (i=0; i<16; i++) { 85 unsigned char c = md5[i]; 86 87 *out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1); 88 *out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1); 89 } 90 *out = '\0'; 91 } 92 93 __be32 94 nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname) 95 { 96 struct xdr_netobj cksum; 97 struct hash_desc desc; 98 struct scatterlist sg; 99 __be32 status = nfserr_resource; 100 101 dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n", 102 clname->len, clname->data); 103 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 104 desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 105 if (IS_ERR(desc.tfm)) 106 goto out_no_tfm; 107 cksum.len = crypto_hash_digestsize(desc.tfm); 108 cksum.data = kmalloc(cksum.len, GFP_KERNEL); 109 if (cksum.data == NULL) 110 goto out; 111 112 sg_init_one(&sg, clname->data, clname->len); 113 114 if (crypto_hash_digest(&desc, &sg, sg.length, cksum.data)) 115 goto out; 116 117 md5_to_hex(dname, cksum.data); 118 119 status = nfs_ok; 120 out: 121 kfree(cksum.data); 122 crypto_free_hash(desc.tfm); 123 out_no_tfm: 124 return status; 125 } 126 127 static void 128 nfsd4_sync_rec_dir(void) 129 { 130 mutex_lock(&rec_dir.dentry->d_inode->i_mutex); 131 nfsd_sync_dir(rec_dir.dentry); 132 mutex_unlock(&rec_dir.dentry->d_inode->i_mutex); 133 } 134 135 int 136 nfsd4_create_clid_dir(struct nfs4_client *clp) 137 { 138 const struct cred *original_cred; 139 char *dname = clp->cl_recdir; 140 struct dentry *dentry; 141 int status; 142 143 dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname); 144 145 if (!rec_dir_init || clp->cl_firststate) 146 return 0; 147 148 status = nfs4_save_creds(&original_cred); 149 if (status < 0) 150 return status; 151 152 /* lock the parent */ 153 mutex_lock(&rec_dir.dentry->d_inode->i_mutex); 154 155 dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1); 156 if (IS_ERR(dentry)) { 157 status = PTR_ERR(dentry); 158 goto out_unlock; 159 } 160 status = -EEXIST; 161 if (dentry->d_inode) { 162 dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n"); 163 goto out_put; 164 } 165 status = mnt_want_write(rec_dir.mnt); 166 if (status) 167 goto out_put; 168 status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU); 169 mnt_drop_write(rec_dir.mnt); 170 out_put: 171 dput(dentry); 172 out_unlock: 173 mutex_unlock(&rec_dir.dentry->d_inode->i_mutex); 174 if (status == 0) { 175 clp->cl_firststate = 1; 176 nfsd4_sync_rec_dir(); 177 } 178 nfs4_reset_creds(original_cred); 179 dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status); 180 return status; 181 } 182 183 typedef int (recdir_func)(struct dentry *, struct dentry *); 184 185 struct dentry_list { 186 struct dentry *dentry; 187 struct list_head list; 188 }; 189 190 struct dentry_list_arg { 191 struct list_head dentries; 192 struct dentry *parent; 193 }; 194 195 static int 196 nfsd4_build_dentrylist(void *arg, const char *name, int namlen, 197 loff_t offset, u64 ino, unsigned int d_type) 198 { 199 struct dentry_list_arg *dla = arg; 200 struct list_head *dentries = &dla->dentries; 201 struct dentry *parent = dla->parent; 202 struct dentry *dentry; 203 struct dentry_list *child; 204 205 if (name && isdotent(name, namlen)) 206 return 0; 207 dentry = lookup_one_len(name, parent, namlen); 208 if (IS_ERR(dentry)) 209 return PTR_ERR(dentry); 210 child = kmalloc(sizeof(*child), GFP_KERNEL); 211 if (child == NULL) 212 return -ENOMEM; 213 child->dentry = dentry; 214 list_add(&child->list, dentries); 215 return 0; 216 } 217 218 static int 219 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f) 220 { 221 const struct cred *original_cred; 222 struct file *filp; 223 struct dentry_list_arg dla = { 224 .parent = dir, 225 }; 226 struct list_head *dentries = &dla.dentries; 227 struct dentry_list *child; 228 int status; 229 230 if (!rec_dir_init) 231 return 0; 232 233 status = nfs4_save_creds(&original_cred); 234 if (status < 0) 235 return status; 236 INIT_LIST_HEAD(dentries); 237 238 filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY, 239 current_cred()); 240 status = PTR_ERR(filp); 241 if (IS_ERR(filp)) 242 goto out; 243 INIT_LIST_HEAD(dentries); 244 status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla); 245 fput(filp); 246 while (!list_empty(dentries)) { 247 child = list_entry(dentries->next, struct dentry_list, list); 248 status = f(dir, child->dentry); 249 if (status) 250 goto out; 251 list_del(&child->list); 252 dput(child->dentry); 253 kfree(child); 254 } 255 out: 256 while (!list_empty(dentries)) { 257 child = list_entry(dentries->next, struct dentry_list, list); 258 list_del(&child->list); 259 dput(child->dentry); 260 kfree(child); 261 } 262 nfs4_reset_creds(original_cred); 263 return status; 264 } 265 266 static int 267 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry) 268 { 269 int status; 270 271 if (!S_ISREG(dir->d_inode->i_mode)) { 272 printk("nfsd4: non-file found in client recovery directory\n"); 273 return -EINVAL; 274 } 275 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); 276 status = vfs_unlink(dir->d_inode, dentry); 277 mutex_unlock(&dir->d_inode->i_mutex); 278 return status; 279 } 280 281 static int 282 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry) 283 { 284 int status; 285 286 /* For now this directory should already be empty, but we empty it of 287 * any regular files anyway, just in case the directory was created by 288 * a kernel from the future.... */ 289 nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file); 290 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); 291 status = vfs_rmdir(dir->d_inode, dentry); 292 mutex_unlock(&dir->d_inode->i_mutex); 293 return status; 294 } 295 296 static int 297 nfsd4_unlink_clid_dir(char *name, int namlen) 298 { 299 struct dentry *dentry; 300 int status; 301 302 dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name); 303 304 mutex_lock(&rec_dir.dentry->d_inode->i_mutex); 305 dentry = lookup_one_len(name, rec_dir.dentry, namlen); 306 mutex_unlock(&rec_dir.dentry->d_inode->i_mutex); 307 if (IS_ERR(dentry)) { 308 status = PTR_ERR(dentry); 309 return status; 310 } 311 status = -ENOENT; 312 if (!dentry->d_inode) 313 goto out; 314 315 status = nfsd4_clear_clid_dir(rec_dir.dentry, dentry); 316 out: 317 dput(dentry); 318 return status; 319 } 320 321 void 322 nfsd4_remove_clid_dir(struct nfs4_client *clp) 323 { 324 const struct cred *original_cred; 325 int status; 326 327 if (!rec_dir_init || !clp->cl_firststate) 328 return; 329 330 status = mnt_want_write(rec_dir.mnt); 331 if (status) 332 goto out; 333 clp->cl_firststate = 0; 334 335 status = nfs4_save_creds(&original_cred); 336 if (status < 0) 337 goto out; 338 339 status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1); 340 nfs4_reset_creds(original_cred); 341 if (status == 0) 342 nfsd4_sync_rec_dir(); 343 mnt_drop_write(rec_dir.mnt); 344 out: 345 if (status) 346 printk("NFSD: Failed to remove expired client state directory" 347 " %.*s\n", HEXDIR_LEN, clp->cl_recdir); 348 return; 349 } 350 351 static int 352 purge_old(struct dentry *parent, struct dentry *child) 353 { 354 int status; 355 356 if (nfs4_has_reclaimed_state(child->d_name.name)) 357 return 0; 358 359 status = nfsd4_clear_clid_dir(parent, child); 360 if (status) 361 printk("failed to remove client recovery directory %s\n", 362 child->d_name.name); 363 /* Keep trying, success or failure: */ 364 return 0; 365 } 366 367 void 368 nfsd4_recdir_purge_old(void) { 369 int status; 370 371 if (!rec_dir_init) 372 return; 373 status = mnt_want_write(rec_dir.mnt); 374 if (status) 375 goto out; 376 status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old); 377 if (status == 0) 378 nfsd4_sync_rec_dir(); 379 mnt_drop_write(rec_dir.mnt); 380 out: 381 if (status) 382 printk("nfsd4: failed to purge old clients from recovery" 383 " directory %s\n", rec_dir.dentry->d_name.name); 384 } 385 386 static int 387 load_recdir(struct dentry *parent, struct dentry *child) 388 { 389 if (child->d_name.len != HEXDIR_LEN - 1) { 390 printk("nfsd4: illegal name %s in recovery directory\n", 391 child->d_name.name); 392 /* Keep trying; maybe the others are OK: */ 393 return 0; 394 } 395 nfs4_client_to_reclaim(child->d_name.name); 396 return 0; 397 } 398 399 int 400 nfsd4_recdir_load(void) { 401 int status; 402 403 status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir); 404 if (status) 405 printk("nfsd4: failed loading clients from recovery" 406 " directory %s\n", rec_dir.dentry->d_name.name); 407 return status; 408 } 409 410 /* 411 * Hold reference to the recovery directory. 412 */ 413 414 void 415 nfsd4_init_recdir(char *rec_dirname) 416 { 417 const struct cred *original_cred; 418 int status; 419 420 printk("NFSD: Using %s as the NFSv4 state recovery directory\n", 421 rec_dirname); 422 423 BUG_ON(rec_dir_init); 424 425 status = nfs4_save_creds(&original_cred); 426 if (status < 0) { 427 printk("NFSD: Unable to change credentials to find recovery" 428 " directory: error %d\n", 429 status); 430 return; 431 } 432 433 status = kern_path(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, 434 &rec_dir); 435 if (status) 436 printk("NFSD: unable to find recovery directory %s\n", 437 rec_dirname); 438 439 if (!status) 440 rec_dir_init = 1; 441 nfs4_reset_creds(original_cred); 442 } 443 444 void 445 nfsd4_shutdown_recdir(void) 446 { 447 if (!rec_dir_init) 448 return; 449 rec_dir_init = 0; 450 path_put(&rec_dir); 451 } 452