linux-stable/include/linux/posix_acl.h
Christian Brauner e4cc916303
acl: add vfs_set_acl()
In previous patches we implemented get and set inode operations for all
non-stacking filesystems that support posix acls but didn't yet
implement get and/or set acl inode operations. This specifically
affected cifs and 9p.

Now we can build a posix acl api based solely on get and set inode
operations. We add a new vfs_set_acl() api that can be used to set posix
acls. This finally removes all type unsafety and type conversion issues
explained in detail in [1] that we aim to get rid of.

After we finished building the vfs api we can switch stacking
filesystems to rely on the new posix api and then finally switch the
xattr system calls themselves to rely on the posix acl api.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-20 10:13:29 +02:00

143 lines
3.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
File: linux/posix_acl.h
(C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
*/
#ifndef __LINUX_POSIX_ACL_H
#define __LINUX_POSIX_ACL_H
#include <linux/bug.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>
#include <linux/refcount.h>
#include <uapi/linux/posix_acl.h>
struct user_namespace;
struct posix_acl_entry {
short e_tag;
unsigned short e_perm;
union {
kuid_t e_uid;
kgid_t e_gid;
};
};
struct posix_acl {
refcount_t a_refcount;
struct rcu_head a_rcu;
unsigned int a_count;
struct posix_acl_entry a_entries[];
};
#define FOREACH_ACL_ENTRY(pa, acl, pe) \
for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
/*
* Duplicate an ACL handle.
*/
static inline struct posix_acl *
posix_acl_dup(struct posix_acl *acl)
{
if (acl)
refcount_inc(&acl->a_refcount);
return acl;
}
/*
* Free an ACL handle.
*/
static inline void
posix_acl_release(struct posix_acl *acl)
{
if (acl && refcount_dec_and_test(&acl->a_refcount))
kfree_rcu(acl, a_rcu);
}
/* posix_acl.c */
extern void posix_acl_init(struct posix_acl *, int);
extern struct posix_acl *posix_acl_alloc(int, gfp_t);
extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
extern int __posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
extern int __posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
extern struct posix_acl *get_posix_acl(struct inode *, int);
int set_posix_acl(struct user_namespace *, struct dentry *, int,
struct posix_acl *);
struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type);
struct posix_acl *posix_acl_clone(const struct posix_acl *acl, gfp_t flags);
#ifdef CONFIG_FS_POSIX_ACL
int posix_acl_chmod(struct user_namespace *, struct dentry *, umode_t);
extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **,
struct posix_acl **);
int posix_acl_update_mode(struct user_namespace *, struct inode *, umode_t *,
struct posix_acl **);
int simple_set_acl(struct user_namespace *, struct dentry *,
struct posix_acl *, int);
extern int simple_acl_create(struct inode *, struct inode *);
struct posix_acl *get_cached_acl(struct inode *inode, int type);
void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl);
void forget_cached_acl(struct inode *inode, int type);
void forget_all_cached_acls(struct inode *inode);
int posix_acl_valid(struct user_namespace *, const struct posix_acl *);
int posix_acl_permission(struct user_namespace *, struct inode *,
const struct posix_acl *, int);
static inline void cache_no_acl(struct inode *inode)
{
inode->i_acl = NULL;
inode->i_default_acl = NULL;
}
int vfs_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
const char *acl_name, struct posix_acl *kacl);
#else
static inline int posix_acl_chmod(struct user_namespace *mnt_userns,
struct dentry *dentry, umode_t mode)
{
return 0;
}
#define simple_set_acl NULL
static inline int simple_acl_create(struct inode *dir, struct inode *inode)
{
return 0;
}
static inline void cache_no_acl(struct inode *inode)
{
}
static inline int posix_acl_create(struct inode *inode, umode_t *mode,
struct posix_acl **default_acl, struct posix_acl **acl)
{
*default_acl = *acl = NULL;
return 0;
}
static inline void forget_all_cached_acls(struct inode *inode)
{
}
static inline int vfs_set_acl(struct user_namespace *mnt_userns,
struct dentry *dentry, const char *name,
struct posix_acl *acl)
{
return -EOPNOTSUPP;
}
#endif /* CONFIG_FS_POSIX_ACL */
struct posix_acl *get_inode_acl(struct inode *inode, int type);
#endif /* __LINUX_POSIX_ACL_H */