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

   1 #ifdef CONFIG_BCACHEFS_POSIX_ACL
   2
   3 #include "bcachefs.h"
   4
   5 #include <linux/fs.h>
   6 #include <linux/posix_acl.h>
   7 #include <linux/posix_acl_xattr.h>
   8 #include <linux/sched.h>
   9 #include <linux/slab.h>
  10
  11 #include "acl.h"
  12 #include "fs.h"
  13 #include "xattr.h"
  14
  15 static inline size_t bch2_acl_size(unsigned nr_short, unsigned nr_long)
  16 {
  17         return sizeof(bch_acl_header) +
  18                 sizeof(bch_acl_entry_short) * nr_short +
  19                 sizeof(bch_acl_entry) * nr_long;
  20 }
  21
  22 static inline int acl_to_xattr_type(int type)
  23 {
  24         switch (type) {
  25         case ACL_TYPE_ACCESS:
  26                 return BCH_XATTR_INDEX_POSIX_ACL_ACCESS;
  27         case ACL_TYPE_DEFAULT:
  28                 return BCH_XATTR_INDEX_POSIX_ACL_DEFAULT;
  29         default:
  30                 BUG();
  31         }
  32 }
  33
  34 /*
  35  * Convert from filesystem to in-memory representation.
  36  */
  37 static struct posix_acl *bch2_acl_from_disk(const void *value, size_t size)
  38 {
  39         const void *p, *end = value + size;
  40         struct posix_acl *acl;
  41         struct posix_acl_entry *out;
  42         unsigned count = 0;
  43
  44         if (!value)
  45                 return NULL;
  46         if (size < sizeof(bch_acl_header))
  47                 goto invalid;
  48         if (((bch_acl_header *)value)->a_version !=
  49             cpu_to_le32(BCH_ACL_VERSION))
  50                 goto invalid;
  51
  52         p = value + sizeof(bch_acl_header);
  53         while (p < end) {
  54                 const bch_acl_entry *entry = p;
  55
  56                 if (p + sizeof(bch_acl_entry_short) > end)
  57                         goto invalid;
  58
  59                 switch (le16_to_cpu(entry->e_tag)) {
  60                 case ACL_USER_OBJ:
  61                 case ACL_GROUP_OBJ:
  62                 case ACL_MASK:
  63                 case ACL_OTHER:
  64                         p += sizeof(bch_acl_entry_short);
  65                         break;
  66                 case ACL_USER:
  67                 case ACL_GROUP:
  68                         p += sizeof(bch_acl_entry);
  69                         break;
  70                 default:
  71                         goto invalid;
  72                 }
  73
  74                 count++;
  75         }
  76
  77         if (p > end)
  78                 goto invalid;
  79
  80         if (!count)
  81                 return NULL;
  82
  83         acl = posix_acl_alloc(count, GFP_KERNEL);
  84         if (!acl)
  85                 return ERR_PTR(-ENOMEM);
  86
  87         out = acl->a_entries;
  88
  89         p = value + sizeof(bch_acl_header);
  90         while (p < end) {
  91                 const bch_acl_entry *in = p;
  92
  93                 out->e_tag  = le16_to_cpu(in->e_tag);
  94                 out->e_perm = le16_to_cpu(in->e_perm);
  95
  96                 switch (out->e_tag) {
  97                 case ACL_USER_OBJ:
  98                 case ACL_GROUP_OBJ:
  99                 case ACL_MASK:
 100                 case ACL_OTHER:
 101                         p += sizeof(bch_acl_entry_short);
 102                         break;
 103                 case ACL_USER:
 104                         out->e_uid = make_kuid(&init_user_ns,
 105                                                le32_to_cpu(in->e_id));
 106                         p += sizeof(bch_acl_entry);
 107                         break;
 108                 case ACL_GROUP:
 109                         out->e_gid = make_kgid(&init_user_ns,
 110                                                le32_to_cpu(in->e_id));
 111                         p += sizeof(bch_acl_entry);
 112                         break;
 113                 }
 114
 115                 out++;
 116         }
 117
 118         BUG_ON(out != acl->a_entries + acl->a_count);
 119
 120         return acl;
 121 invalid:
 122         pr_err("invalid acl entry");
 123         return ERR_PTR(-EINVAL);
 124 }
 125
 126 #define acl_for_each_entry(acl, acl_e)                  \
 127         for (acl_e = acl->a_entries;                    \
 128              acl_e < acl->a_entries + acl->a_count;     \
 129              acl_e++)
 130
 131 /*
 132  * Convert from in-memory to filesystem representation.
 133  */
 134 static struct bkey_i_xattr *
 135 bch2_acl_to_xattr(struct btree_trans *trans,
 136                   const struct posix_acl *acl,
 137                   int type)
 138 {
 139         struct bkey_i_xattr *xattr;
 140         bch_acl_header *acl_header;
 141         const struct posix_acl_entry *acl_e;
 142         void *outptr;
 143         unsigned nr_short = 0, nr_long = 0, acl_len, u64s;
 144
 145         acl_for_each_entry(acl, acl_e) {
 146                 switch (acl_e->e_tag) {
 147                 case ACL_USER:
 148                 case ACL_GROUP:
 149                         nr_long++;
 150                         break;
 151                 case ACL_USER_OBJ:
 152                 case ACL_GROUP_OBJ:
 153                 case ACL_MASK:
 154                 case ACL_OTHER:
 155                         nr_short++;
 156                         break;
 157                 default:
 158                         return ERR_PTR(-EINVAL);
 159                 }
 160         }
 161
 162         acl_len = bch2_acl_size(nr_short, nr_long);
 163         u64s = BKEY_U64s + xattr_val_u64s(0, acl_len);
 164
 165         if (u64s > U8_MAX)
 166                 return ERR_PTR(-E2BIG);
 167
 168         xattr = bch2_trans_kmalloc(trans, u64s * sizeof(u64));
 169         if (IS_ERR(xattr))
 170                 return xattr;
 171
 172         bkey_xattr_init(&xattr->k_i);
 173         xattr->k.u64s           = u64s;
 174         xattr->v.x_type         = acl_to_xattr_type(type);
 175         xattr->v.x_name_len     = 0,
 176         xattr->v.x_val_len      = cpu_to_le16(acl_len);
 177
 178         acl_header = xattr_val(&xattr->v);
 179         acl_header->a_version = cpu_to_le32(BCH_ACL_VERSION);
 180
 181         outptr = (void *) acl_header + sizeof(*acl_header);
 182
 183         acl_for_each_entry(acl, acl_e) {
 184                 bch_acl_entry *entry = outptr;
 185
 186                 entry->e_tag = cpu_to_le16(acl_e->e_tag);
 187                 entry->e_perm = cpu_to_le16(acl_e->e_perm);
 188                 switch (acl_e->e_tag) {
 189                 case ACL_USER:
 190                         entry->e_id = cpu_to_le32(
 191                                 from_kuid(&init_user_ns, acl_e->e_uid));
 192                         outptr += sizeof(bch_acl_entry);
 193                         break;
 194                 case ACL_GROUP:
 195                         entry->e_id = cpu_to_le32(
 196                                 from_kgid(&init_user_ns, acl_e->e_gid));
 197                         outptr += sizeof(bch_acl_entry);
 198                         break;
 199
 200                 case ACL_USER_OBJ:
 201                 case ACL_GROUP_OBJ:
 202                 case ACL_MASK:
 203                 case ACL_OTHER:
 204                         outptr += sizeof(bch_acl_entry_short);
 205                         break;
 206                 }
 207         }
 208
 209         BUG_ON(outptr != xattr_val(&xattr->v) + acl_len);
 210
 211         return xattr;
 212 }
 213
 214 struct posix_acl *bch2_get_acl(struct inode *vinode, int type)
 215 {
 216         struct bch_inode_info *inode = to_bch_ei(vinode);
 217         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 218         struct btree_trans trans;
 219         struct btree_iter *iter;
 220         struct bkey_s_c_xattr xattr;
 221         struct posix_acl *acl = NULL;
 222
 223         bch2_trans_init(&trans, c);
 224 retry:
 225         bch2_trans_begin(&trans);
 226
 227         iter = bch2_hash_lookup(&trans, bch2_xattr_hash_desc,
 228                         &inode->ei_str_hash, inode->v.i_ino,
 229                         &X_SEARCH(acl_to_xattr_type(type), "", 0),
 230                         0);
 231         if (IS_ERR(iter)) {
 232                 if (PTR_ERR(iter) == -EINTR)
 233                         goto retry;
 234
 235                 if (PTR_ERR(iter) != -ENOENT)
 236                         acl = ERR_CAST(iter);
 237                 goto out;
 238         }
 239
 240         xattr = bkey_s_c_to_xattr(bch2_btree_iter_peek_slot(iter));
 241
 242         acl = bch2_acl_from_disk(xattr_val(xattr.v),
 243                         le16_to_cpu(xattr.v->x_val_len));
 244
 245         if (!IS_ERR(acl))
 246                 set_cached_acl(&inode->v, type, acl);
 247 out:
 248         bch2_trans_exit(&trans);
 249         return acl;
 250 }
 251
 252 int bch2_set_acl_trans(struct btree_trans *trans,
 253                        struct bch_inode_unpacked *inode_u,
 254                        const struct bch_hash_info *hash_info,
 255                        struct posix_acl *acl, int type)
 256 {
 257         int ret;
 258
 259         if (type == ACL_TYPE_DEFAULT &&
 260             !S_ISDIR(inode_u->bi_mode))
 261                 return acl ? -EACCES : 0;
 262
 263         if (acl) {
 264                 struct bkey_i_xattr *xattr =
 265                         bch2_acl_to_xattr(trans, acl, type);
 266                 if (IS_ERR(xattr))
 267                         return PTR_ERR(xattr);
 268
 269                 ret = __bch2_hash_set(trans, bch2_xattr_hash_desc, hash_info,
 270                                       inode_u->bi_inum, &xattr->k_i, 0);
 271         } else {
 272                 struct xattr_search_key search =
 273                         X_SEARCH(acl_to_xattr_type(type), "", 0);
 274
 275                 ret = bch2_hash_delete(trans, bch2_xattr_hash_desc, hash_info,
 276                                        inode_u->bi_inum, &search);
 277         }
 278
 279         return ret == -ENOENT ? 0 : ret;
 280 }
 281
 282 static int inode_update_for_set_acl_fn(struct bch_inode_info *inode,
 283                                        struct bch_inode_unpacked *bi,
 284                                        void *p)
 285 {
 286         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 287         struct timespec now = current_time(&inode->v);
 288         umode_t mode = (unsigned long) p;
 289
 290         bi->bi_ctime    = timespec_to_bch2_time(c, now);
 291         bi->bi_mode     = mode;
 292         return 0;
 293 }
 294
 295 int bch2_set_acl(struct inode *vinode, struct posix_acl *acl, int type)
 296 {
 297         struct bch_inode_info *inode = to_bch_ei(vinode);
 298         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 299         struct btree_trans trans;
 300         struct bch_inode_unpacked inode_u;
 301         umode_t mode = inode->v.i_mode;
 302         int ret;
 303
 304         if (type == ACL_TYPE_ACCESS && acl) {
 305                 ret = posix_acl_update_mode(&inode->v, &mode, &acl);
 306                 if (ret)
 307                         return ret;
 308         }
 309
 310         bch2_trans_init(&trans, c);
 311 retry:
 312         bch2_trans_begin(&trans);
 313
 314         ret   = bch2_set_acl_trans(&trans,
 315                                    &inode->ei_inode,
 316                                    &inode->ei_str_hash,
 317                                    acl, type) ?:
 318                 bch2_write_inode_trans(&trans, inode, &inode_u,
 319                                        inode_update_for_set_acl_fn,
 320                                        (void *)(unsigned long) mode) ?:
 321                 bch2_trans_commit(&trans, NULL, NULL,
 322                                   &inode->ei_journal_seq,
 323                                   BTREE_INSERT_ATOMIC|
 324                                   BTREE_INSERT_NOUNLOCK);
 325         if (ret == -EINTR)
 326                 goto retry;
 327         if (unlikely(ret))
 328                 goto err;
 329
 330         bch2_inode_update_after_write(c, inode, &inode_u,
 331                                       ATTR_CTIME|ATTR_MODE);
 332
 333         set_cached_acl(&inode->v, type, acl);
 334 err:
 335         bch2_trans_exit(&trans);
 336
 337         return ret;
 338 }
 339
 340 int bch2_acl_chmod(struct btree_trans *trans,
 341                    struct bch_inode_info *inode,
 342                    umode_t mode,
 343                    struct posix_acl **new_acl)
 344 {
 345         struct btree_iter *iter;
 346         struct bkey_s_c_xattr xattr;
 347         struct bkey_i_xattr *new;
 348         struct posix_acl *acl;
 349         int ret = 0;
 350
 351         iter = bch2_hash_lookup(trans, bch2_xattr_hash_desc,
 352                         &inode->ei_str_hash, inode->v.i_ino,
 353                         &X_SEARCH(BCH_XATTR_INDEX_POSIX_ACL_ACCESS, "", 0),
 354                         BTREE_ITER_INTENT);
 355         if (IS_ERR(iter))
 356                 return PTR_ERR(iter) != -ENOENT ? PTR_ERR(iter) : 0;
 357
 358         xattr = bkey_s_c_to_xattr(bch2_btree_iter_peek_slot(iter));
 359
 360         acl = bch2_acl_from_disk(xattr_val(xattr.v),
 361                         le16_to_cpu(xattr.v->x_val_len));
 362         if (IS_ERR_OR_NULL(acl))
 363                 return PTR_ERR(acl);
 364
 365         ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
 366         if (ret)
 367                 goto err;
 368
 369         new = bch2_acl_to_xattr(trans, acl, ACL_TYPE_ACCESS);
 370         if (IS_ERR(new)) {
 371                 ret = PTR_ERR(new);
 372                 goto err;
 373         }
 374
 375         bch2_trans_update(trans, iter, &new->k_i, 0);
 376         *new_acl = acl;
 377         acl = NULL;
 378 err:
 379         kfree(acl);
 380         return ret;
 381 }
 382
 383 #endif /* CONFIG_BCACHEFS_POSIX_ACL */