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![Christian Brauner](/assets/img/avatar_default.png)
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b
("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
411 lines
9.8 KiB
C
411 lines
9.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/capability.h>
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#include <linux/fs.h>
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#include <linux/posix_acl.h>
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#include "reiserfs.h"
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#include <linux/errno.h>
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#include <linux/pagemap.h>
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#include <linux/xattr.h>
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#include <linux/slab.h>
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#include <linux/posix_acl_xattr.h>
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#include "xattr.h"
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#include "acl.h"
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#include <linux/uaccess.h>
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static int __reiserfs_set_acl(struct reiserfs_transaction_handle *th,
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struct inode *inode, int type,
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struct posix_acl *acl);
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int
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reiserfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
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struct posix_acl *acl, int type)
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{
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int error, error2;
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struct reiserfs_transaction_handle th;
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size_t jcreate_blocks;
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int size = acl ? posix_acl_xattr_size(acl->a_count) : 0;
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int update_mode = 0;
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struct inode *inode = d_inode(dentry);
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umode_t mode = inode->i_mode;
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/*
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* Pessimism: We can't assume that anything from the xattr root up
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* has been created.
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*/
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jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
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reiserfs_xattr_nblocks(inode, size) * 2;
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reiserfs_write_lock(inode->i_sb);
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error = journal_begin(&th, inode->i_sb, jcreate_blocks);
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reiserfs_write_unlock(inode->i_sb);
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if (error == 0) {
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if (type == ACL_TYPE_ACCESS && acl) {
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error = posix_acl_update_mode(&nop_mnt_idmap, inode,
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&mode, &acl);
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if (error)
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goto unlock;
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update_mode = 1;
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}
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error = __reiserfs_set_acl(&th, inode, type, acl);
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if (!error && update_mode)
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inode->i_mode = mode;
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unlock:
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reiserfs_write_lock(inode->i_sb);
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error2 = journal_end(&th);
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reiserfs_write_unlock(inode->i_sb);
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if (error2)
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error = error2;
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}
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return error;
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}
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/*
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* Convert from filesystem to in-memory representation.
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*/
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static struct posix_acl *reiserfs_posix_acl_from_disk(const void *value, size_t size)
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{
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const char *end = (char *)value + size;
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int n, count;
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struct posix_acl *acl;
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if (!value)
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return NULL;
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if (size < sizeof(reiserfs_acl_header))
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return ERR_PTR(-EINVAL);
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if (((reiserfs_acl_header *) value)->a_version !=
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cpu_to_le32(REISERFS_ACL_VERSION))
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return ERR_PTR(-EINVAL);
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value = (char *)value + sizeof(reiserfs_acl_header);
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count = reiserfs_acl_count(size);
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if (count < 0)
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return ERR_PTR(-EINVAL);
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if (count == 0)
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return NULL;
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acl = posix_acl_alloc(count, GFP_NOFS);
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if (!acl)
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return ERR_PTR(-ENOMEM);
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for (n = 0; n < count; n++) {
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reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
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if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
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goto fail;
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acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
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acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
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switch (acl->a_entries[n].e_tag) {
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case ACL_USER_OBJ:
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case ACL_GROUP_OBJ:
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case ACL_MASK:
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case ACL_OTHER:
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value = (char *)value +
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sizeof(reiserfs_acl_entry_short);
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break;
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case ACL_USER:
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value = (char *)value + sizeof(reiserfs_acl_entry);
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if ((char *)value > end)
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goto fail;
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acl->a_entries[n].e_uid =
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make_kuid(&init_user_ns,
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le32_to_cpu(entry->e_id));
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break;
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case ACL_GROUP:
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value = (char *)value + sizeof(reiserfs_acl_entry);
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if ((char *)value > end)
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goto fail;
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acl->a_entries[n].e_gid =
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make_kgid(&init_user_ns,
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le32_to_cpu(entry->e_id));
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break;
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default:
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goto fail;
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}
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}
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if (value != end)
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goto fail;
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return acl;
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fail:
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posix_acl_release(acl);
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return ERR_PTR(-EINVAL);
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}
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/*
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* Convert from in-memory to filesystem representation.
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*/
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static void *reiserfs_posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
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{
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reiserfs_acl_header *ext_acl;
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char *e;
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int n;
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*size = reiserfs_acl_size(acl->a_count);
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ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
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acl->a_count *
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sizeof(reiserfs_acl_entry),
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GFP_NOFS);
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if (!ext_acl)
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return ERR_PTR(-ENOMEM);
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ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
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e = (char *)ext_acl + sizeof(reiserfs_acl_header);
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for (n = 0; n < acl->a_count; n++) {
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const struct posix_acl_entry *acl_e = &acl->a_entries[n];
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reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
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entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
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entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
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switch (acl->a_entries[n].e_tag) {
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case ACL_USER:
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entry->e_id = cpu_to_le32(
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from_kuid(&init_user_ns, acl_e->e_uid));
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e += sizeof(reiserfs_acl_entry);
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break;
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case ACL_GROUP:
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entry->e_id = cpu_to_le32(
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from_kgid(&init_user_ns, acl_e->e_gid));
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e += sizeof(reiserfs_acl_entry);
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break;
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case ACL_USER_OBJ:
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case ACL_GROUP_OBJ:
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case ACL_MASK:
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case ACL_OTHER:
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e += sizeof(reiserfs_acl_entry_short);
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break;
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default:
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goto fail;
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}
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}
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return (char *)ext_acl;
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fail:
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kfree(ext_acl);
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return ERR_PTR(-EINVAL);
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}
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/*
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* Inode operation get_posix_acl().
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*
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* inode->i_mutex: down
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* BKL held [before 2.5.x]
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*/
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struct posix_acl *reiserfs_get_acl(struct inode *inode, int type, bool rcu)
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{
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char *name, *value;
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struct posix_acl *acl;
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int size;
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int retval;
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if (rcu)
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return ERR_PTR(-ECHILD);
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switch (type) {
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case ACL_TYPE_ACCESS:
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name = XATTR_NAME_POSIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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name = XATTR_NAME_POSIX_ACL_DEFAULT;
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break;
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default:
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BUG();
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}
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size = reiserfs_xattr_get(inode, name, NULL, 0);
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if (size < 0) {
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if (size == -ENODATA || size == -ENOSYS)
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return NULL;
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return ERR_PTR(size);
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}
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value = kmalloc(size, GFP_NOFS);
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if (!value)
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return ERR_PTR(-ENOMEM);
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retval = reiserfs_xattr_get(inode, name, value, size);
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if (retval == -ENODATA || retval == -ENOSYS) {
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/*
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* This shouldn't actually happen as it should have
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* been caught above.. but just in case
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*/
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acl = NULL;
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} else if (retval < 0) {
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acl = ERR_PTR(retval);
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} else {
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acl = reiserfs_posix_acl_from_disk(value, retval);
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}
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kfree(value);
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return acl;
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}
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/*
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* Inode operation set_posix_acl().
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*
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* inode->i_mutex: down
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* BKL held [before 2.5.x]
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*/
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static int
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__reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
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int type, struct posix_acl *acl)
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{
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char *name;
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void *value = NULL;
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size_t size = 0;
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int error;
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switch (type) {
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case ACL_TYPE_ACCESS:
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name = XATTR_NAME_POSIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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name = XATTR_NAME_POSIX_ACL_DEFAULT;
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if (!S_ISDIR(inode->i_mode))
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return acl ? -EACCES : 0;
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break;
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default:
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return -EINVAL;
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}
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if (acl) {
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value = reiserfs_posix_acl_to_disk(acl, &size);
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if (IS_ERR(value))
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return (int)PTR_ERR(value);
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}
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error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
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/*
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* Ensure that the inode gets dirtied if we're only using
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* the mode bits and an old ACL didn't exist. We don't need
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* to check if the inode is hashed here since we won't get
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* called by reiserfs_inherit_default_acl().
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*/
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if (error == -ENODATA) {
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error = 0;
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if (type == ACL_TYPE_ACCESS) {
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inode->i_ctime = current_time(inode);
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mark_inode_dirty(inode);
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}
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}
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kfree(value);
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if (!error)
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set_cached_acl(inode, type, acl);
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return error;
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}
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/*
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* dir->i_mutex: locked,
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* inode is new and not released into the wild yet
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*/
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int
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reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
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struct inode *dir, struct dentry *dentry,
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struct inode *inode)
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{
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struct posix_acl *default_acl, *acl;
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int err = 0;
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/* ACLs only get applied to files and directories */
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if (S_ISLNK(inode->i_mode))
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return 0;
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/*
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* ACLs can only be used on "new" objects, so if it's an old object
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* there is nothing to inherit from
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*/
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if (get_inode_sd_version(dir) == STAT_DATA_V1)
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goto apply_umask;
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/*
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* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
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* would be useless since permissions are ignored, and a pain because
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* it introduces locking cycles
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*/
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if (IS_PRIVATE(inode))
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goto apply_umask;
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err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
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if (err)
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return err;
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if (default_acl) {
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err = __reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
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default_acl);
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posix_acl_release(default_acl);
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}
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if (acl) {
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if (!err)
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err = __reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS,
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acl);
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posix_acl_release(acl);
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}
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return err;
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apply_umask:
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/* no ACL, apply umask */
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inode->i_mode &= ~current_umask();
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return err;
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}
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/* This is used to cache the default acl before a new object is created.
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* The biggest reason for this is to get an idea of how many blocks will
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* actually be required for the create operation if we must inherit an ACL.
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* An ACL write can add up to 3 object creations and an additional file write
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* so we'd prefer not to reserve that many blocks in the journal if we can.
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* It also has the advantage of not loading the ACL with a transaction open,
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* this may seem silly, but if the owner of the directory is doing the
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* creation, the ACL may not be loaded since the permissions wouldn't require
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* it.
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* We return the number of blocks required for the transaction.
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*/
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int reiserfs_cache_default_acl(struct inode *inode)
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{
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struct posix_acl *acl;
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int nblocks = 0;
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if (IS_PRIVATE(inode))
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return 0;
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acl = get_inode_acl(inode, ACL_TYPE_DEFAULT);
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if (acl && !IS_ERR(acl)) {
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int size = reiserfs_acl_size(acl->a_count);
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/* Other xattrs can be created during inode creation. We don't
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* want to claim too many blocks, so we check to see if we
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* need to create the tree to the xattrs, and then we
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* just want two files. */
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nblocks = reiserfs_xattr_jcreate_nblocks(inode);
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nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
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REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
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/* We need to account for writes + bitmaps for two files */
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nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
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posix_acl_release(acl);
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}
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return nblocks;
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}
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/*
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* Called under i_mutex
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*/
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int reiserfs_acl_chmod(struct dentry *dentry)
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{
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struct inode *inode = d_inode(dentry);
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if (IS_PRIVATE(inode))
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return 0;
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if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
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!reiserfs_posixacl(inode->i_sb))
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return 0;
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return posix_acl_chmod(&nop_mnt_idmap, dentry, inode->i_mode);
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}
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