git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/acl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #ifdef CONFIG_BCACHEFS_POSIX_ACL
   3
   4 #include "bcachefs.h"
   5
   6 #include <linux/fs.h>
   7 #include <linux/posix_acl.h>
   8 #include <linux/posix_acl_xattr.h>
   9 #include <linux/sched.h>
  10 #include <linux/slab.h>
  11
  12 #include "acl.h"
  13 #include "fs.h"
  14 #include "xattr.h"
  15
  16 static inline size_t bch2_acl_size(unsigned nr_short, unsigned nr_long)
  17 {
  18         return sizeof(bch_acl_header) +
  19                 sizeof(bch_acl_entry_short) * nr_short +
  20                 sizeof(bch_acl_entry) * nr_long;
  21 }
  22
  23 static inline int acl_to_xattr_type(int type)
  24 {
  25         switch (type) {
  26         case ACL_TYPE_ACCESS:
  27                 return KEY_TYPE_XATTR_INDEX_POSIX_ACL_ACCESS;
  28         case ACL_TYPE_DEFAULT:
  29                 return KEY_TYPE_XATTR_INDEX_POSIX_ACL_DEFAULT;
  30         default:
  31                 BUG();
  32         }
  33 }
  34
  35 /*
  36  * Convert from filesystem to in-memory representation.
  37  */
  38 static struct posix_acl *bch2_acl_from_disk(struct btree_trans *trans,
  39                                             const void *value, size_t size)
  40 {
  41         const void *p, *end = value + size;
  42         struct posix_acl *acl;
  43         struct posix_acl_entry *out;
  44         unsigned count = 0;
  45         int ret;
  46
  47         if (!value)
  48                 return NULL;
  49         if (size < sizeof(bch_acl_header))
  50                 goto invalid;
  51         if (((bch_acl_header *)value)->a_version !=
  52             cpu_to_le32(BCH_ACL_VERSION))
  53                 goto invalid;
  54
  55         p = value + sizeof(bch_acl_header);
  56         while (p < end) {
  57                 const bch_acl_entry *entry = p;
  58
  59                 if (p + sizeof(bch_acl_entry_short) > end)
  60                         goto invalid;
  61
  62                 switch (le16_to_cpu(entry->e_tag)) {
  63                 case ACL_USER_OBJ:
  64                 case ACL_GROUP_OBJ:
  65                 case ACL_MASK:
  66                 case ACL_OTHER:
  67                         p += sizeof(bch_acl_entry_short);
  68                         break;
  69                 case ACL_USER:
  70                 case ACL_GROUP:
  71                         p += sizeof(bch_acl_entry);
  72                         break;
  73                 default:
  74                         goto invalid;
  75                 }
  76
  77                 count++;
  78         }
  79
  80         if (p > end)
  81                 goto invalid;
  82
  83         if (!count)
  84                 return NULL;
  85
  86         acl = allocate_dropping_locks(trans, ret,
  87                         posix_acl_alloc(count, _gfp));
  88         if (!acl)
  89                 return ERR_PTR(-ENOMEM);
  90         if (ret) {
  91                 kfree(acl);
  92                 return ERR_PTR(ret);
  93         }
  94
  95         out = acl->a_entries;
  96
  97         p = value + sizeof(bch_acl_header);
  98         while (p < end) {
  99                 const bch_acl_entry *in = p;
 100
 101                 out->e_tag  = le16_to_cpu(in->e_tag);
 102                 out->e_perm = le16_to_cpu(in->e_perm);
 103
 104                 switch (out->e_tag) {
 105                 case ACL_USER_OBJ:
 106                 case ACL_GROUP_OBJ:
 107                 case ACL_MASK:
 108                 case ACL_OTHER:
 109                         p += sizeof(bch_acl_entry_short);
 110                         break;
 111                 case ACL_USER:
 112                         out->e_uid = make_kuid(&init_user_ns,
 113                                                le32_to_cpu(in->e_id));
 114                         p += sizeof(bch_acl_entry);
 115                         break;
 116                 case ACL_GROUP:
 117                         out->e_gid = make_kgid(&init_user_ns,
 118                                                le32_to_cpu(in->e_id));
 119                         p += sizeof(bch_acl_entry);
 120                         break;
 121                 }
 122
 123                 out++;
 124         }
 125
 126         BUG_ON(out != acl->a_entries + acl->a_count);
 127
 128         return acl;
 129 invalid:
 130         pr_err("invalid acl entry");
 131         return ERR_PTR(-EINVAL);
 132 }
 133
 134 #define acl_for_each_entry(acl, acl_e)                  \
 135         for (acl_e = acl->a_entries;                    \
 136              acl_e < acl->a_entries + acl->a_count;     \
 137              acl_e++)
 138
 139 /*
 140  * Convert from in-memory to filesystem representation.
 141  */
 142 static struct bkey_i_xattr *
 143 bch2_acl_to_xattr(struct btree_trans *trans,
 144                   const struct posix_acl *acl,
 145                   int type)
 146 {
 147         struct bkey_i_xattr *xattr;
 148         bch_acl_header *acl_header;
 149         const struct posix_acl_entry *acl_e;
 150         void *outptr;
 151         unsigned nr_short = 0, nr_long = 0, acl_len, u64s;
 152
 153         acl_for_each_entry(acl, acl_e) {
 154                 switch (acl_e->e_tag) {
 155                 case ACL_USER:
 156                 case ACL_GROUP:
 157                         nr_long++;
 158                         break;
 159                 case ACL_USER_OBJ:
 160                 case ACL_GROUP_OBJ:
 161                 case ACL_MASK:
 162                 case ACL_OTHER:
 163                         nr_short++;
 164                         break;
 165                 default:
 166                         return ERR_PTR(-EINVAL);
 167                 }
 168         }
 169
 170         acl_len = bch2_acl_size(nr_short, nr_long);
 171         u64s = BKEY_U64s + xattr_val_u64s(0, acl_len);
 172
 173         if (u64s > U8_MAX)
 174                 return ERR_PTR(-E2BIG);
 175
 176         xattr = bch2_trans_kmalloc(trans, u64s * sizeof(u64));
 177         if (IS_ERR(xattr))
 178                 return xattr;
 179
 180         bkey_xattr_init(&xattr->k_i);
 181         xattr->k.u64s           = u64s;
 182         xattr->v.x_type         = acl_to_xattr_type(type);
 183         xattr->v.x_name_len     = 0;
 184         xattr->v.x_val_len      = cpu_to_le16(acl_len);
 185
 186         acl_header = xattr_val(&xattr->v);
 187         acl_header->a_version = cpu_to_le32(BCH_ACL_VERSION);
 188
 189         outptr = (void *) acl_header + sizeof(*acl_header);
 190
 191         acl_for_each_entry(acl, acl_e) {
 192                 bch_acl_entry *entry = outptr;
 193
 194                 entry->e_tag = cpu_to_le16(acl_e->e_tag);
 195                 entry->e_perm = cpu_to_le16(acl_e->e_perm);
 196                 switch (acl_e->e_tag) {
 197                 case ACL_USER:
 198                         entry->e_id = cpu_to_le32(
 199                                 from_kuid(&init_user_ns, acl_e->e_uid));
 200                         outptr += sizeof(bch_acl_entry);
 201                         break;
 202                 case ACL_GROUP:
 203                         entry->e_id = cpu_to_le32(
 204                                 from_kgid(&init_user_ns, acl_e->e_gid));
 205                         outptr += sizeof(bch_acl_entry);
 206                         break;
 207
 208                 case ACL_USER_OBJ:
 209                 case ACL_GROUP_OBJ:
 210                 case ACL_MASK:
 211                 case ACL_OTHER:
 212                         outptr += sizeof(bch_acl_entry_short);
 213                         break;
 214                 }
 215         }
 216
 217         BUG_ON(outptr != xattr_val(&xattr->v) + acl_len);
 218
 219         return xattr;
 220 }
 221
 222 struct posix_acl *bch2_get_acl(struct mnt_idmap *idmap,
 223                                struct dentry *dentry, int type)
 224 {
 225         struct bch_inode_info *inode = to_bch_ei(dentry->d_inode);
 226         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 227         struct bch_hash_info hash = bch2_hash_info_init(c, &inode->ei_inode);
 228         struct xattr_search_key search = X_SEARCH(acl_to_xattr_type(type), "", 0);
 229         struct btree_trans trans;
 230         struct btree_iter iter = { NULL };
 231         struct bkey_s_c_xattr xattr;
 232         struct posix_acl *acl = NULL;
 233         struct bkey_s_c k;
 234         int ret;
 235
 236         bch2_trans_init(&trans, c, 0, 0);
 237 retry:
 238         bch2_trans_begin(&trans);
 239
 240         ret = bch2_hash_lookup(&trans, &iter, bch2_xattr_hash_desc,
 241                         &hash, inode_inum(inode), &search, 0);
 242         if (ret) {
 243                 if (!bch2_err_matches(ret, ENOENT))
 244                         acl = ERR_PTR(ret);
 245                 goto out;
 246         }
 247
 248         k = bch2_btree_iter_peek_slot(&iter);
 249         ret = bkey_err(k);
 250         if (ret) {
 251                 acl = ERR_PTR(ret);
 252                 goto out;
 253         }
 254
 255         xattr = bkey_s_c_to_xattr(k);
 256         acl = bch2_acl_from_disk(&trans, xattr_val(xattr.v),
 257                         le16_to_cpu(xattr.v->x_val_len));
 258
 259         if (!IS_ERR(acl))
 260                 set_cached_acl(&inode->v, type, acl);
 261 out:
 262         if (bch2_err_matches(PTR_ERR_OR_ZERO(acl), BCH_ERR_transaction_restart))
 263                 goto retry;
 264
 265         bch2_trans_iter_exit(&trans, &iter);
 266         bch2_trans_exit(&trans);
 267         return acl;
 268 }
 269
 270 int bch2_set_acl_trans(struct btree_trans *trans, subvol_inum inum,
 271                        struct bch_inode_unpacked *inode_u,
 272                        struct posix_acl *acl, int type)
 273 {
 274         struct bch_hash_info hash_info = bch2_hash_info_init(trans->c, inode_u);
 275         int ret;
 276
 277         if (type == ACL_TYPE_DEFAULT &&
 278             !S_ISDIR(inode_u->bi_mode))
 279                 return acl ? -EACCES : 0;
 280
 281         if (acl) {
 282                 struct bkey_i_xattr *xattr =
 283                         bch2_acl_to_xattr(trans, acl, type);
 284                 if (IS_ERR(xattr))
 285                         return PTR_ERR(xattr);
 286
 287                 ret = bch2_hash_set(trans, bch2_xattr_hash_desc, &hash_info,
 288                                     inum, &xattr->k_i, 0);
 289         } else {
 290                 struct xattr_search_key search =
 291                         X_SEARCH(acl_to_xattr_type(type), "", 0);
 292
 293                 ret = bch2_hash_delete(trans, bch2_xattr_hash_desc, &hash_info,
 294                                        inum, &search);
 295         }
 296
 297         return bch2_err_matches(ret, ENOENT) ? 0 : ret;
 298 }
 299
 300 int bch2_set_acl(struct mnt_idmap *idmap,
 301                  struct dentry *dentry,
 302                  struct posix_acl *_acl, int type)
 303 {
 304         struct bch_inode_info *inode = to_bch_ei(dentry->d_inode);
 305         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 306         struct btree_trans trans;
 307         struct btree_iter inode_iter = { NULL };
 308         struct bch_inode_unpacked inode_u;
 309         struct posix_acl *acl;
 310         umode_t mode;
 311         int ret;
 312
 313         mutex_lock(&inode->ei_update_lock);
 314         bch2_trans_init(&trans, c, 0, 0);
 315 retry:
 316         bch2_trans_begin(&trans);
 317         acl = _acl;
 318
 319         ret = bch2_inode_peek(&trans, &inode_iter, &inode_u, inode_inum(inode),
 320                               BTREE_ITER_INTENT);
 321         if (ret)
 322                 goto btree_err;
 323
 324         mode = inode_u.bi_mode;
 325
 326         if (type == ACL_TYPE_ACCESS) {
 327                 ret = posix_acl_update_mode(idmap, &inode->v, &mode, &acl);
 328                 if (ret)
 329                         goto btree_err;
 330         }
 331
 332         ret = bch2_set_acl_trans(&trans, inode_inum(inode), &inode_u, acl, type);
 333         if (ret)
 334                 goto btree_err;
 335
 336         inode_u.bi_ctime        = bch2_current_time(c);
 337         inode_u.bi_mode         = mode;
 338
 339         ret =   bch2_inode_write(&trans, &inode_iter, &inode_u) ?:
 340                 bch2_trans_commit(&trans, NULL, NULL, 0);
 341 btree_err:
 342         bch2_trans_iter_exit(&trans, &inode_iter);
 343
 344         if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 345                 goto retry;
 346         if (unlikely(ret))
 347                 goto err;
 348
 349         bch2_inode_update_after_write(&trans, inode, &inode_u,
 350                                       ATTR_CTIME|ATTR_MODE);
 351
 352         set_cached_acl(&inode->v, type, acl);
 353 err:
 354         bch2_trans_exit(&trans);
 355         mutex_unlock(&inode->ei_update_lock);
 356
 357         return ret;
 358 }
 359
 360 int bch2_acl_chmod(struct btree_trans *trans, subvol_inum inum,
 361                    struct bch_inode_unpacked *inode,
 362                    umode_t mode,
 363                    struct posix_acl **new_acl)
 364 {
 365         struct bch_hash_info hash_info = bch2_hash_info_init(trans->c, inode);
 366         struct xattr_search_key search = X_SEARCH(KEY_TYPE_XATTR_INDEX_POSIX_ACL_ACCESS, "", 0);
 367         struct btree_iter iter;
 368         struct bkey_s_c_xattr xattr;
 369         struct bkey_i_xattr *new;
 370         struct posix_acl *acl;
 371         struct bkey_s_c k;
 372         int ret;
 373
 374         ret = bch2_hash_lookup(trans, &iter, bch2_xattr_hash_desc,
 375                                &hash_info, inum, &search, BTREE_ITER_INTENT);
 376         if (ret)
 377                 return bch2_err_matches(ret, ENOENT) ? 0 : ret;
 378
 379         k = bch2_btree_iter_peek_slot(&iter);
 380         xattr = bkey_s_c_to_xattr(k);
 381         if (ret)
 382                 goto err;
 383
 384         acl = bch2_acl_from_disk(trans, xattr_val(xattr.v),
 385                         le16_to_cpu(xattr.v->x_val_len));
 386         ret = PTR_ERR_OR_ZERO(acl);
 387         if (IS_ERR_OR_NULL(acl))
 388                 goto err;
 389
 390         ret = allocate_dropping_locks_errcode(trans,
 391                                 __posix_acl_chmod(&acl, _gfp, mode));
 392         if (ret)
 393                 goto err;
 394
 395         new = bch2_acl_to_xattr(trans, acl, ACL_TYPE_ACCESS);
 396         if (IS_ERR(new)) {
 397                 ret = PTR_ERR(new);
 398                 goto err;
 399         }
 400
 401         new->k.p = iter.pos;
 402         ret = bch2_trans_update(trans, &iter, &new->k_i, 0);
 403         *new_acl = acl;
 404         acl = NULL;
 405 err:
 406         bch2_trans_iter_exit(trans, &iter);
 407         if (!IS_ERR_OR_NULL(acl))
 408                 kfree(acl);
 409         return ret;
 410 }
 411
 412 #endif /* CONFIG_BCACHEFS_POSIX_ACL */