diff options
Diffstat (limited to 'fs/bcachefs/acl.c')
| -rw-r--r-- | fs/bcachefs/acl.c | 387 |
1 files changed, 387 insertions, 0 deletions
diff --git a/fs/bcachefs/acl.c b/fs/bcachefs/acl.c new file mode 100644 index 000000000000..eaf5c8e138fb --- /dev/null +++ b/fs/bcachefs/acl.c @@ -0,0 +1,387 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifdef CONFIG_BCACHEFS_POSIX_ACL + +#include "bcachefs.h" + +#include <linux/fs.h> +#include <linux/posix_acl.h> +#include <linux/posix_acl_xattr.h> +#include <linux/sched.h> +#include <linux/slab.h> + +#include "acl.h" +#include "fs.h" +#include "xattr.h" + +static inline size_t bch2_acl_size(unsigned nr_short, unsigned nr_long) +{ + return sizeof(bch_acl_header) + + sizeof(bch_acl_entry_short) * nr_short + + sizeof(bch_acl_entry) * nr_long; +} + +static inline int acl_to_xattr_type(int type) +{ + switch (type) { + case ACL_TYPE_ACCESS: + return BCH_XATTR_INDEX_POSIX_ACL_ACCESS; + case ACL_TYPE_DEFAULT: + return BCH_XATTR_INDEX_POSIX_ACL_DEFAULT; + default: + BUG(); + } +} + +/* + * Convert from filesystem to in-memory representation. + */ +static struct posix_acl *bch2_acl_from_disk(const void *value, size_t size) +{ + const void *p, *end = value + size; + struct posix_acl *acl; + struct posix_acl_entry *out; + unsigned count = 0; + + if (!value) + return NULL; + if (size < sizeof(bch_acl_header)) + goto invalid; + if (((bch_acl_header *)value)->a_version != + cpu_to_le32(BCH_ACL_VERSION)) + goto invalid; + + p = value + sizeof(bch_acl_header); + while (p < end) { + const bch_acl_entry *entry = p; + + if (p + sizeof(bch_acl_entry_short) > end) + goto invalid; + + switch (le16_to_cpu(entry->e_tag)) { + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + p += sizeof(bch_acl_entry_short); + break; + case ACL_USER: + case ACL_GROUP: + p += sizeof(bch_acl_entry); + break; + default: + goto invalid; + } + + count++; + } + + if (p > end) + goto invalid; + + if (!count) + return NULL; + + acl = posix_acl_alloc(count, GFP_KERNEL); + if (!acl) + return ERR_PTR(-ENOMEM); + + out = acl->a_entries; + + p = value + sizeof(bch_acl_header); + while (p < end) { + const bch_acl_entry *in = p; + + out->e_tag = le16_to_cpu(in->e_tag); + out->e_perm = le16_to_cpu(in->e_perm); + + switch (out->e_tag) { + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + p += sizeof(bch_acl_entry_short); + break; + case ACL_USER: + out->e_uid = make_kuid(&init_user_ns, + le32_to_cpu(in->e_id)); + p += sizeof(bch_acl_entry); + break; + case ACL_GROUP: + out->e_gid = make_kgid(&init_user_ns, + le32_to_cpu(in->e_id)); + p += sizeof(bch_acl_entry); + break; + } + + out++; + } + + BUG_ON(out != acl->a_entries + acl->a_count); + + return acl; +invalid: + pr_err("invalid acl entry"); + return ERR_PTR(-EINVAL); +} + +#define acl_for_each_entry(acl, acl_e) \ + for (acl_e = acl->a_entries; \ + acl_e < acl->a_entries + acl->a_count; \ + acl_e++) + +/* + * Convert from in-memory to filesystem representation. + */ +static struct bkey_i_xattr * +bch2_acl_to_xattr(struct btree_trans *trans, + const struct posix_acl *acl, + int type) +{ + struct bkey_i_xattr *xattr; + bch_acl_header *acl_header; + const struct posix_acl_entry *acl_e; + void *outptr; + unsigned nr_short = 0, nr_long = 0, acl_len, u64s; + + acl_for_each_entry(acl, acl_e) { + switch (acl_e->e_tag) { + case ACL_USER: + case ACL_GROUP: + nr_long++; + break; + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + nr_short++; + break; + default: + return ERR_PTR(-EINVAL); + } + } + + acl_len = bch2_acl_size(nr_short, nr_long); + u64s = BKEY_U64s + xattr_val_u64s(0, acl_len); + + if (u64s > U8_MAX) + return ERR_PTR(-E2BIG); + + xattr = bch2_trans_kmalloc(trans, u64s * sizeof(u64)); + if (IS_ERR(xattr)) + return xattr; + + bkey_xattr_init(&xattr->k_i); + xattr->k.u64s = u64s; + xattr->v.x_type = acl_to_xattr_type(type); + xattr->v.x_name_len = 0, + xattr->v.x_val_len = cpu_to_le16(acl_len); + + acl_header = xattr_val(&xattr->v); + acl_header->a_version = cpu_to_le32(BCH_ACL_VERSION); + + outptr = (void *) acl_header + sizeof(*acl_header); + + acl_for_each_entry(acl, acl_e) { + bch_acl_entry *entry = outptr; + + entry->e_tag = cpu_to_le16(acl_e->e_tag); + entry->e_perm = cpu_to_le16(acl_e->e_perm); + switch (acl_e->e_tag) { + case ACL_USER: + entry->e_id = cpu_to_le32( + from_kuid(&init_user_ns, acl_e->e_uid)); + outptr += sizeof(bch_acl_entry); + break; + case ACL_GROUP: + entry->e_id = cpu_to_le32( + from_kgid(&init_user_ns, acl_e->e_gid)); + outptr += sizeof(bch_acl_entry); + break; + + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + outptr += sizeof(bch_acl_entry_short); + break; + } + } + + BUG_ON(outptr != xattr_val(&xattr->v) + acl_len); + + return xattr; +} + +struct posix_acl *bch2_get_acl(struct mnt_idmap *idmap, + struct dentry *dentry, int type) +{ + struct bch_inode_info *inode = to_bch_ei(dentry->d_inode); + struct bch_fs *c = inode->v.i_sb->s_fs_info; + struct btree_trans trans; + struct btree_iter *iter; + struct bkey_s_c_xattr xattr; + struct posix_acl *acl = NULL; + + bch2_trans_init(&trans, c); +retry: + bch2_trans_begin(&trans); + + iter = bch2_hash_lookup(&trans, bch2_xattr_hash_desc, + &inode->ei_str_hash, inode->v.i_ino, + &X_SEARCH(acl_to_xattr_type(type), "", 0), + 0); + if (IS_ERR(iter)) { + if (PTR_ERR(iter) == -EINTR) + goto retry; + + if (PTR_ERR(iter) != -ENOENT) + acl = ERR_CAST(iter); + goto out; + } + + xattr = bkey_s_c_to_xattr(bch2_btree_iter_peek_slot(iter)); + + acl = bch2_acl_from_disk(xattr_val(xattr.v), + le16_to_cpu(xattr.v->x_val_len)); + + if (!IS_ERR(acl)) + set_cached_acl(&inode->v, type, acl); +out: + bch2_trans_exit(&trans); + return acl; +} + +int bch2_set_acl_trans(struct btree_trans *trans, + struct bch_inode_unpacked *inode_u, + const struct bch_hash_info *hash_info, + struct posix_acl *acl, int type) +{ + int ret; + + if (type == ACL_TYPE_DEFAULT && + !S_ISDIR(inode_u->bi_mode)) + return acl ? -EACCES : 0; + + if (acl) { + struct bkey_i_xattr *xattr = + bch2_acl_to_xattr(trans, acl, type); + if (IS_ERR(xattr)) + return PTR_ERR(xattr); + + ret = __bch2_hash_set(trans, bch2_xattr_hash_desc, hash_info, + inode_u->bi_inum, &xattr->k_i, 0); + } else { + struct xattr_search_key search = + X_SEARCH(acl_to_xattr_type(type), "", 0); + + ret = bch2_hash_delete(trans, bch2_xattr_hash_desc, hash_info, + inode_u->bi_inum, &search); + } + + return ret == -ENOENT ? 0 : ret; +} + +static int inode_update_for_set_acl_fn(struct bch_inode_info *inode, + struct bch_inode_unpacked *bi, + void *p) +{ + struct bch_fs *c = inode->v.i_sb->s_fs_info; + struct timespec64 now = current_time(&inode->v); + umode_t mode = (unsigned long) p; + + bi->bi_ctime = timespec_to_bch2_time(c, now); + bi->bi_mode = mode; + return 0; +} + +int bch2_set_acl(struct mnt_idmap *idmap, + struct dentry *dentry, + struct posix_acl *acl, int type) +{ + struct bch_inode_info *inode = to_bch_ei(dentry->d_inode); + struct bch_fs *c = inode->v.i_sb->s_fs_info; + struct btree_trans trans; + struct bch_inode_unpacked inode_u; + umode_t mode = inode->v.i_mode; + int ret; + + if (type == ACL_TYPE_ACCESS && acl) { + ret = posix_acl_update_mode(idmap, &inode->v, &mode, &acl); + if (ret) + return ret; + } + + bch2_trans_init(&trans, c); +retry: + bch2_trans_begin(&trans); + + ret = bch2_set_acl_trans(&trans, + &inode->ei_inode, + &inode->ei_str_hash, + acl, type) ?: + bch2_write_inode_trans(&trans, inode, &inode_u, + inode_update_for_set_acl_fn, + (void *)(unsigned long) mode) ?: + bch2_trans_commit(&trans, NULL, NULL, + &inode->ei_journal_seq, + BTREE_INSERT_ATOMIC| + BTREE_INSERT_NOUNLOCK); + if (ret == -EINTR) + goto retry; + if (unlikely(ret)) + goto err; + + bch2_inode_update_after_write(c, inode, &inode_u, + ATTR_CTIME|ATTR_MODE); + + set_cached_acl(&inode->v, type, acl); +err: + bch2_trans_exit(&trans); + + return ret; +} + +int bch2_acl_chmod(struct btree_trans *trans, + struct bch_inode_info *inode, + umode_t mode, + struct posix_acl **new_acl) +{ + struct btree_iter *iter; + struct bkey_s_c_xattr xattr; + struct bkey_i_xattr *new; + struct posix_acl *acl; + int ret = 0; + + iter = bch2_hash_lookup(trans, bch2_xattr_hash_desc, + &inode->ei_str_hash, inode->v.i_ino, + &X_SEARCH(BCH_XATTR_INDEX_POSIX_ACL_ACCESS, "", 0), + BTREE_ITER_INTENT); + if (IS_ERR(iter)) + return PTR_ERR(iter) != -ENOENT ? PTR_ERR(iter) : 0; + + xattr = bkey_s_c_to_xattr(bch2_btree_iter_peek_slot(iter)); + + acl = bch2_acl_from_disk(xattr_val(xattr.v), + le16_to_cpu(xattr.v->x_val_len)); + if (IS_ERR_OR_NULL(acl)) + return PTR_ERR(acl); + + ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); + if (ret) + goto err; + + new = bch2_acl_to_xattr(trans, acl, ACL_TYPE_ACCESS); + if (IS_ERR(new)) { + ret = PTR_ERR(new); + goto err; + } + + bch2_trans_update(trans, iter, &new->k_i, 0); + *new_acl = acl; + acl = NULL; +err: + kfree(acl); + return ret; +} + +#endif /* CONFIG_BCACHEFS_POSIX_ACL */ |