linux/fs/reiserfs/xattr_acl.c
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   1#include <linux/capability.h>
   2#include <linux/fs.h>
   3#include <linux/posix_acl.h>
   4#include "reiserfs.h"
   5#include <linux/errno.h>
   6#include <linux/pagemap.h>
   7#include <linux/xattr.h>
   8#include <linux/slab.h>
   9#include <linux/posix_acl_xattr.h>
  10#include "xattr.h"
  11#include "acl.h"
  12#include <asm/uaccess.h>
  13
  14static int reiserfs_set_acl(struct reiserfs_transaction_handle *th,
  15                            struct inode *inode, int type,
  16                            struct posix_acl *acl);
  17
  18static int
  19posix_acl_set(struct dentry *dentry, const char *name, const void *value,
  20                size_t size, int flags, int type)
  21{
  22        struct inode *inode = dentry->d_inode;
  23        struct posix_acl *acl;
  24        int error, error2;
  25        struct reiserfs_transaction_handle th;
  26        size_t jcreate_blocks;
  27        if (!reiserfs_posixacl(inode->i_sb))
  28                return -EOPNOTSUPP;
  29        if (!inode_owner_or_capable(inode))
  30                return -EPERM;
  31
  32        if (value) {
  33                acl = posix_acl_from_xattr(value, size);
  34                if (IS_ERR(acl)) {
  35                        return PTR_ERR(acl);
  36                } else if (acl) {
  37                        error = posix_acl_valid(acl);
  38                        if (error)
  39                                goto release_and_out;
  40                }
  41        } else
  42                acl = NULL;
  43
  44        /* Pessimism: We can't assume that anything from the xattr root up
  45         * has been created. */
  46
  47        jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  48                         reiserfs_xattr_nblocks(inode, size) * 2;
  49
  50        reiserfs_write_lock(inode->i_sb);
  51        error = journal_begin(&th, inode->i_sb, jcreate_blocks);
  52        if (error == 0) {
  53                error = reiserfs_set_acl(&th, inode, type, acl);
  54                error2 = journal_end(&th, inode->i_sb, jcreate_blocks);
  55                if (error2)
  56                        error = error2;
  57        }
  58        reiserfs_write_unlock(inode->i_sb);
  59
  60      release_and_out:
  61        posix_acl_release(acl);
  62        return error;
  63}
  64
  65static int
  66posix_acl_get(struct dentry *dentry, const char *name, void *buffer,
  67                size_t size, int type)
  68{
  69        struct posix_acl *acl;
  70        int error;
  71
  72        if (!reiserfs_posixacl(dentry->d_sb))
  73                return -EOPNOTSUPP;
  74
  75        acl = reiserfs_get_acl(dentry->d_inode, type);
  76        if (IS_ERR(acl))
  77                return PTR_ERR(acl);
  78        if (acl == NULL)
  79                return -ENODATA;
  80        error = posix_acl_to_xattr(acl, buffer, size);
  81        posix_acl_release(acl);
  82
  83        return error;
  84}
  85
  86/*
  87 * Convert from filesystem to in-memory representation.
  88 */
  89static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
  90{
  91        const char *end = (char *)value + size;
  92        int n, count;
  93        struct posix_acl *acl;
  94
  95        if (!value)
  96                return NULL;
  97        if (size < sizeof(reiserfs_acl_header))
  98                return ERR_PTR(-EINVAL);
  99        if (((reiserfs_acl_header *) value)->a_version !=
 100            cpu_to_le32(REISERFS_ACL_VERSION))
 101                return ERR_PTR(-EINVAL);
 102        value = (char *)value + sizeof(reiserfs_acl_header);
 103        count = reiserfs_acl_count(size);
 104        if (count < 0)
 105                return ERR_PTR(-EINVAL);
 106        if (count == 0)
 107                return NULL;
 108        acl = posix_acl_alloc(count, GFP_NOFS);
 109        if (!acl)
 110                return ERR_PTR(-ENOMEM);
 111        for (n = 0; n < count; n++) {
 112                reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
 113                if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
 114                        goto fail;
 115                acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
 116                acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
 117                switch (acl->a_entries[n].e_tag) {
 118                case ACL_USER_OBJ:
 119                case ACL_GROUP_OBJ:
 120                case ACL_MASK:
 121                case ACL_OTHER:
 122                        value = (char *)value +
 123                            sizeof(reiserfs_acl_entry_short);
 124                        acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
 125                        break;
 126
 127                case ACL_USER:
 128                case ACL_GROUP:
 129                        value = (char *)value + sizeof(reiserfs_acl_entry);
 130                        if ((char *)value > end)
 131                                goto fail;
 132                        acl->a_entries[n].e_id = le32_to_cpu(entry->e_id);
 133                        break;
 134
 135                default:
 136                        goto fail;
 137                }
 138        }
 139        if (value != end)
 140                goto fail;
 141        return acl;
 142
 143      fail:
 144        posix_acl_release(acl);
 145        return ERR_PTR(-EINVAL);
 146}
 147
 148/*
 149 * Convert from in-memory to filesystem representation.
 150 */
 151static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
 152{
 153        reiserfs_acl_header *ext_acl;
 154        char *e;
 155        int n;
 156
 157        *size = reiserfs_acl_size(acl->a_count);
 158        ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
 159                                                  acl->a_count *
 160                                                  sizeof(reiserfs_acl_entry),
 161                                                  GFP_NOFS);
 162        if (!ext_acl)
 163                return ERR_PTR(-ENOMEM);
 164        ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
 165        e = (char *)ext_acl + sizeof(reiserfs_acl_header);
 166        for (n = 0; n < acl->a_count; n++) {
 167                reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
 168                entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
 169                entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
 170                switch (acl->a_entries[n].e_tag) {
 171                case ACL_USER:
 172                case ACL_GROUP:
 173                        entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
 174                        e += sizeof(reiserfs_acl_entry);
 175                        break;
 176
 177                case ACL_USER_OBJ:
 178                case ACL_GROUP_OBJ:
 179                case ACL_MASK:
 180                case ACL_OTHER:
 181                        e += sizeof(reiserfs_acl_entry_short);
 182                        break;
 183
 184                default:
 185                        goto fail;
 186                }
 187        }
 188        return (char *)ext_acl;
 189
 190      fail:
 191        kfree(ext_acl);
 192        return ERR_PTR(-EINVAL);
 193}
 194
 195/*
 196 * Inode operation get_posix_acl().
 197 *
 198 * inode->i_mutex: down
 199 * BKL held [before 2.5.x]
 200 */
 201struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
 202{
 203        char *name, *value;
 204        struct posix_acl *acl;
 205        int size;
 206        int retval;
 207
 208        acl = get_cached_acl(inode, type);
 209        if (acl != ACL_NOT_CACHED)
 210                return acl;
 211
 212        switch (type) {
 213        case ACL_TYPE_ACCESS:
 214                name = POSIX_ACL_XATTR_ACCESS;
 215                break;
 216        case ACL_TYPE_DEFAULT:
 217                name = POSIX_ACL_XATTR_DEFAULT;
 218                break;
 219        default:
 220                BUG();
 221        }
 222
 223        size = reiserfs_xattr_get(inode, name, NULL, 0);
 224        if (size < 0) {
 225                if (size == -ENODATA || size == -ENOSYS) {
 226                        set_cached_acl(inode, type, NULL);
 227                        return NULL;
 228                }
 229                return ERR_PTR(size);
 230        }
 231
 232        value = kmalloc(size, GFP_NOFS);
 233        if (!value)
 234                return ERR_PTR(-ENOMEM);
 235
 236        retval = reiserfs_xattr_get(inode, name, value, size);
 237        if (retval == -ENODATA || retval == -ENOSYS) {
 238                /* This shouldn't actually happen as it should have
 239                   been caught above.. but just in case */
 240                acl = NULL;
 241        } else if (retval < 0) {
 242                acl = ERR_PTR(retval);
 243        } else {
 244                acl = posix_acl_from_disk(value, retval);
 245        }
 246        if (!IS_ERR(acl))
 247                set_cached_acl(inode, type, acl);
 248
 249        kfree(value);
 250        return acl;
 251}
 252
 253/*
 254 * Inode operation set_posix_acl().
 255 *
 256 * inode->i_mutex: down
 257 * BKL held [before 2.5.x]
 258 */
 259static int
 260reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
 261                 int type, struct posix_acl *acl)
 262{
 263        char *name;
 264        void *value = NULL;
 265        size_t size = 0;
 266        int error;
 267
 268        if (S_ISLNK(inode->i_mode))
 269                return -EOPNOTSUPP;
 270
 271        switch (type) {
 272        case ACL_TYPE_ACCESS:
 273                name = POSIX_ACL_XATTR_ACCESS;
 274                if (acl) {
 275                        error = posix_acl_equiv_mode(acl, &inode->i_mode);
 276                        if (error < 0)
 277                                return error;
 278                        else {
 279                                if (error == 0)
 280                                        acl = NULL;
 281                        }
 282                }
 283                break;
 284        case ACL_TYPE_DEFAULT:
 285                name = POSIX_ACL_XATTR_DEFAULT;
 286                if (!S_ISDIR(inode->i_mode))
 287                        return acl ? -EACCES : 0;
 288                break;
 289        default:
 290                return -EINVAL;
 291        }
 292
 293        if (acl) {
 294                value = posix_acl_to_disk(acl, &size);
 295                if (IS_ERR(value))
 296                        return (int)PTR_ERR(value);
 297        }
 298
 299        error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
 300
 301        /*
 302         * Ensure that the inode gets dirtied if we're only using
 303         * the mode bits and an old ACL didn't exist. We don't need
 304         * to check if the inode is hashed here since we won't get
 305         * called by reiserfs_inherit_default_acl().
 306         */
 307        if (error == -ENODATA) {
 308                error = 0;
 309                if (type == ACL_TYPE_ACCESS) {
 310                        inode->i_ctime = CURRENT_TIME_SEC;
 311                        mark_inode_dirty(inode);
 312                }
 313        }
 314
 315        kfree(value);
 316
 317        if (!error)
 318                set_cached_acl(inode, type, acl);
 319
 320        return error;
 321}
 322
 323/* dir->i_mutex: locked,
 324 * inode is new and not released into the wild yet */
 325int
 326reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
 327                             struct inode *dir, struct dentry *dentry,
 328                             struct inode *inode)
 329{
 330        struct posix_acl *acl;
 331        int err = 0;
 332
 333        /* ACLs only get applied to files and directories */
 334        if (S_ISLNK(inode->i_mode))
 335                return 0;
 336
 337        /* ACLs can only be used on "new" objects, so if it's an old object
 338         * there is nothing to inherit from */
 339        if (get_inode_sd_version(dir) == STAT_DATA_V1)
 340                goto apply_umask;
 341
 342        /* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
 343         * would be useless since permissions are ignored, and a pain because
 344         * it introduces locking cycles */
 345        if (IS_PRIVATE(dir)) {
 346                inode->i_flags |= S_PRIVATE;
 347                goto apply_umask;
 348        }
 349
 350        acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
 351        if (IS_ERR(acl))
 352                return PTR_ERR(acl);
 353
 354        if (acl) {
 355                /* Copy the default ACL to the default ACL of a new directory */
 356                if (S_ISDIR(inode->i_mode)) {
 357                        err = reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
 358                                               acl);
 359                        if (err)
 360                                goto cleanup;
 361                }
 362
 363                /* Now we reconcile the new ACL and the mode,
 364                   potentially modifying both */
 365                err = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
 366                if (err < 0)
 367                        return err;
 368
 369                /* If we need an ACL.. */
 370                if (err > 0)
 371                        err = reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS, acl);
 372              cleanup:
 373                posix_acl_release(acl);
 374        } else {
 375              apply_umask:
 376                /* no ACL, apply umask */
 377                inode->i_mode &= ~current_umask();
 378        }
 379
 380        return err;
 381}
 382
 383/* This is used to cache the default acl before a new object is created.
 384 * The biggest reason for this is to get an idea of how many blocks will
 385 * actually be required for the create operation if we must inherit an ACL.
 386 * An ACL write can add up to 3 object creations and an additional file write
 387 * so we'd prefer not to reserve that many blocks in the journal if we can.
 388 * It also has the advantage of not loading the ACL with a transaction open,
 389 * this may seem silly, but if the owner of the directory is doing the
 390 * creation, the ACL may not be loaded since the permissions wouldn't require
 391 * it.
 392 * We return the number of blocks required for the transaction.
 393 */
 394int reiserfs_cache_default_acl(struct inode *inode)
 395{
 396        struct posix_acl *acl;
 397        int nblocks = 0;
 398
 399        if (IS_PRIVATE(inode))
 400                return 0;
 401
 402        acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
 403
 404        if (acl && !IS_ERR(acl)) {
 405                int size = reiserfs_acl_size(acl->a_count);
 406
 407                /* Other xattrs can be created during inode creation. We don't
 408                 * want to claim too many blocks, so we check to see if we
 409                 * we need to create the tree to the xattrs, and then we
 410                 * just want two files. */
 411                nblocks = reiserfs_xattr_jcreate_nblocks(inode);
 412                nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
 413
 414                REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 415
 416                /* We need to account for writes + bitmaps for two files */
 417                nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
 418                posix_acl_release(acl);
 419        }
 420
 421        return nblocks;
 422}
 423
 424int reiserfs_acl_chmod(struct inode *inode)
 425{
 426        struct reiserfs_transaction_handle th;
 427        struct posix_acl *acl;
 428        size_t size;
 429        int depth;
 430        int error;
 431
 432        if (S_ISLNK(inode->i_mode))
 433                return -EOPNOTSUPP;
 434
 435        if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
 436            !reiserfs_posixacl(inode->i_sb)) {
 437                return 0;
 438        }
 439
 440        reiserfs_write_unlock(inode->i_sb);
 441        acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
 442        reiserfs_write_lock(inode->i_sb);
 443        if (!acl)
 444                return 0;
 445        if (IS_ERR(acl))
 446                return PTR_ERR(acl);
 447        error = posix_acl_chmod(&acl, GFP_NOFS, inode->i_mode);
 448        if (error)
 449                return error;
 450
 451        size = reiserfs_xattr_nblocks(inode, reiserfs_acl_size(acl->a_count));
 452        depth = reiserfs_write_lock_once(inode->i_sb);
 453        error = journal_begin(&th, inode->i_sb, size * 2);
 454        if (!error) {
 455                int error2;
 456                error = reiserfs_set_acl(&th, inode, ACL_TYPE_ACCESS, acl);
 457                error2 = journal_end(&th, inode->i_sb, size * 2);
 458                if (error2)
 459                        error = error2;
 460        }
 461        reiserfs_write_unlock_once(inode->i_sb, depth);
 462        posix_acl_release(acl);
 463        return error;
 464}
 465
 466static size_t posix_acl_access_list(struct dentry *dentry, char *list,
 467                                    size_t list_size, const char *name,
 468                                    size_t name_len, int type)
 469{
 470        const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
 471        if (!reiserfs_posixacl(dentry->d_sb))
 472                return 0;
 473        if (list && size <= list_size)
 474                memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
 475        return size;
 476}
 477
 478const struct xattr_handler reiserfs_posix_acl_access_handler = {
 479        .prefix = POSIX_ACL_XATTR_ACCESS,
 480        .flags = ACL_TYPE_ACCESS,
 481        .get = posix_acl_get,
 482        .set = posix_acl_set,
 483        .list = posix_acl_access_list,
 484};
 485
 486static size_t posix_acl_default_list(struct dentry *dentry, char *list,
 487                                     size_t list_size, const char *name,
 488                                     size_t name_len, int type)
 489{
 490        const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
 491        if (!reiserfs_posixacl(dentry->d_sb))
 492                return 0;
 493        if (list && size <= list_size)
 494                memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
 495        return size;
 496}
 497
 498const struct xattr_handler reiserfs_posix_acl_default_handler = {
 499        .prefix = POSIX_ACL_XATTR_DEFAULT,
 500        .flags = ACL_TYPE_DEFAULT,
 501        .get = posix_acl_get,
 502        .set = posix_acl_set,
 503        .list = posix_acl_default_list,
 504};
 505
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