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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>
304 lines
6.7 KiB
C
304 lines
6.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/ext4/acl.c
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*
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* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
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*/
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#include <linux/quotaops.h>
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#include "ext4_jbd2.h"
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#include "ext4.h"
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#include "xattr.h"
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#include "acl.h"
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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 *
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ext4_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(ext4_acl_header))
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return ERR_PTR(-EINVAL);
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if (((ext4_acl_header *)value)->a_version !=
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cpu_to_le32(EXT4_ACL_VERSION))
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return ERR_PTR(-EINVAL);
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value = (char *)value + sizeof(ext4_acl_header);
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count = ext4_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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ext4_acl_entry *entry =
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(ext4_acl_entry *)value;
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if ((char *)value + sizeof(ext4_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(ext4_acl_entry_short);
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break;
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case ACL_USER:
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value = (char *)value + sizeof(ext4_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(ext4_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 *
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ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
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{
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ext4_acl_header *ext_acl;
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char *e;
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size_t n;
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*size = ext4_acl_size(acl->a_count);
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ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
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sizeof(ext4_acl_entry), 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(EXT4_ACL_VERSION);
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e = (char *)ext_acl + sizeof(ext4_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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ext4_acl_entry *entry = (ext4_acl_entry *)e;
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entry->e_tag = cpu_to_le16(acl_e->e_tag);
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entry->e_perm = cpu_to_le16(acl_e->e_perm);
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switch (acl_e->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(ext4_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(ext4_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(ext4_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_rwsem: don't care
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*/
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struct posix_acl *
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ext4_get_acl(struct inode *inode, int type, bool rcu)
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{
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int name_index;
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char *value = NULL;
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struct posix_acl *acl;
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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_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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name_index = EXT4_XATTR_INDEX_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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retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
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if (retval > 0) {
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value = kmalloc(retval, GFP_NOFS);
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if (!value)
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return ERR_PTR(-ENOMEM);
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retval = ext4_xattr_get(inode, name_index, "", value, retval);
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}
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if (retval > 0)
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acl = ext4_acl_from_disk(value, retval);
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else if (retval == -ENODATA || retval == -ENOSYS)
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acl = NULL;
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else
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acl = ERR_PTR(retval);
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kfree(value);
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return acl;
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}
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/*
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* Set the access or default ACL of an inode.
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*
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* inode->i_rwsem: down unless called from ext4_new_inode
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*/
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static int
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__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
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struct posix_acl *acl, int xattr_flags)
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{
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int name_index;
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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_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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name_index = EXT4_XATTR_INDEX_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 = ext4_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 = ext4_xattr_set_handle(handle, inode, name_index, "",
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value, size, xattr_flags);
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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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int
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ext4_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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handle_t *handle;
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int error, credits, retries = 0;
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size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 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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int update_mode = 0;
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error = dquot_initialize(inode);
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if (error)
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return error;
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retry:
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error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */,
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&credits);
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if (error)
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return error;
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handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
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if (IS_ERR(handle))
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return PTR_ERR(handle);
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if ((type == ACL_TYPE_ACCESS) && acl) {
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error = posix_acl_update_mode(idmap, inode, &mode, &acl);
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if (error)
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goto out_stop;
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if (mode != inode->i_mode)
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update_mode = 1;
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}
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error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
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if (!error && update_mode) {
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inode->i_mode = mode;
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inode->i_ctime = current_time(inode);
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error = ext4_mark_inode_dirty(handle, inode);
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}
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out_stop:
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ext4_journal_stop(handle);
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if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
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goto retry;
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return error;
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}
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/*
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* Initialize the ACLs of a new inode. Called from ext4_new_inode.
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*
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* dir->i_rwsem: down
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* inode->i_rwsem: up (access to inode is still exclusive)
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*/
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int
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ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
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{
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struct posix_acl *default_acl, *acl;
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int error;
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error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
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if (error)
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return error;
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if (default_acl) {
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error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
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default_acl, XATTR_CREATE);
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posix_acl_release(default_acl);
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} else {
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inode->i_default_acl = NULL;
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}
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if (acl) {
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if (!error)
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error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
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acl, XATTR_CREATE);
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posix_acl_release(acl);
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} else {
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inode->i_acl = NULL;
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}
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return error;
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}
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