Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org>
 *
 * Fixes from William Schumacher incorporated on 15 March 2001.
 *    (Reported by Charles Bertsch, <CBertsch@microtest.com>).
 */
 
/*
 *  This file contains generic functions for manipulating
 *  POSIX 1003.1e draft standard 17 ACLs.
 */
 
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
#include <linux/export.h>
#include <linux/user_namespace.h>
 
static struct posix_acl **acl_by_type(struct inode *inode, int type)
{
<------>switch (type) {
<------>case ACL_TYPE_ACCESS:
<------><------>return &inode->i_acl;
<------>case ACL_TYPE_DEFAULT:
<------><------>return &inode->i_default_acl;
<------>default:
<------><------>BUG();
<------>}
}
 
struct posix_acl *get_cached_acl(struct inode *inode, int type)
{
<------>struct posix_acl **p = acl_by_type(inode, type);
<------>struct posix_acl *acl;
 
<------>for (;;) {
<------><------>rcu_read_lock();
<------><------>acl = rcu_dereference(*p);
<------><------>if (!acl || is_uncached_acl(acl) ||
<------><------>    refcount_inc_not_zero(&acl->a_refcount))
<------><------><------>break;
<------><------>rcu_read_unlock();
<------><------>cpu_relax();
<------>}
<------>rcu_read_unlock();
<------>return acl;
}
EXPORT_SYMBOL(get_cached_acl);
 
struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
{
<------>return rcu_dereference(*acl_by_type(inode, type));
}
EXPORT_SYMBOL(get_cached_acl_rcu);
 
void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
{
<------>struct posix_acl **p = acl_by_type(inode, type);
<------>struct posix_acl *old;
 
<------>old = xchg(p, posix_acl_dup(acl));
<------>if (!is_uncached_acl(old))
<------><------>posix_acl_release(old);
}
EXPORT_SYMBOL(set_cached_acl);
 
static void __forget_cached_acl(struct posix_acl **p)
{
<------>struct posix_acl *old;
 
<------>old = xchg(p, ACL_NOT_CACHED);
<------>if (!is_uncached_acl(old))
<------><------>posix_acl_release(old);
}
 
void forget_cached_acl(struct inode *inode, int type)
{
<------>__forget_cached_acl(acl_by_type(inode, type));
}
EXPORT_SYMBOL(forget_cached_acl);
 
void forget_all_cached_acls(struct inode *inode)
{
<------>__forget_cached_acl(&inode->i_acl);
<------>__forget_cached_acl(&inode->i_default_acl);
}
EXPORT_SYMBOL(forget_all_cached_acls);
 
struct posix_acl *get_acl(struct inode *inode, int type)
{
<------>void *sentinel;
<------>struct posix_acl **p;
<------>struct posix_acl *acl;
 
<------>/*
<------> * The sentinel is used to detect when another operation like
<------> * set_cached_acl() or forget_cached_acl() races with get_acl().
<------> * It is guaranteed that is_uncached_acl(sentinel) is true.
<------> */
 
<------>acl = get_cached_acl(inode, type);
<------>if (!is_uncached_acl(acl))
<------><------>return acl;
 
<------>if (!IS_POSIXACL(inode))
<------><------>return NULL;
 
<------>sentinel = uncached_acl_sentinel(current);
<------>p = acl_by_type(inode, type);
 
<------>/*
<------> * If the ACL isn't being read yet, set our sentinel.  Otherwise, the
<------> * current value of the ACL will not be ACL_NOT_CACHED and so our own
<------> * sentinel will not be set; another task will update the cache.  We
<------> * could wait for that other task to complete its job, but it's easier
<------> * to just call ->get_acl to fetch the ACL ourself.  (This is going to
<------> * be an unlikely race.)
<------> */
<------>if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED)
<------><------>/* fall through */ ;
 
<------>/*
<------> * Normally, the ACL returned by ->get_acl will be cached.
<------> * A filesystem can prevent that by calling
<------> * forget_cached_acl(inode, type) in ->get_acl.
<------> *
<------> * If the filesystem doesn't have a get_acl() function at all, we'll
<------> * just create the negative cache entry.
<------> */
<------>if (!inode->i_op->get_acl) {
<------><------>set_cached_acl(inode, type, NULL);
<------><------>return NULL;
<------>}
<------>acl = inode->i_op->get_acl(inode, type);
 
<------>if (IS_ERR(acl)) {
<------><------>/*
<------><------> * Remove our sentinel so that we don't block future attempts
<------><------> * to cache the ACL.
<------><------> */
<------><------>cmpxchg(p, sentinel, ACL_NOT_CACHED);
<------><------>return acl;
<------>}
 
<------>/*
<------> * Cache the result, but only if our sentinel is still in place.
<------> */
<------>posix_acl_dup(acl);
<------>if (unlikely(cmpxchg(p, sentinel, acl) != sentinel))
<------><------>posix_acl_release(acl);
<------>return acl;
}
EXPORT_SYMBOL(get_acl);
 
/*
 * Init a fresh posix_acl
 */
void
posix_acl_init(struct posix_acl *acl, int count)
{
<------>refcount_set(&acl->a_refcount, 1);
<------>acl->a_count = count;
}
EXPORT_SYMBOL(posix_acl_init);
 
/*
 * Allocate a new ACL with the specified number of entries.
 */
struct posix_acl *
posix_acl_alloc(int count, gfp_t flags)
{
<------>const size_t size = sizeof(struct posix_acl) +
<------>                    count * sizeof(struct posix_acl_entry);
<------>struct posix_acl *acl = kmalloc(size, flags);
<------>if (acl)
<------><------>posix_acl_init(acl, count);
<------>return acl;
}
EXPORT_SYMBOL(posix_acl_alloc);
 
/*
 * Clone an ACL.
 */
static struct posix_acl *
posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
{
<------>struct posix_acl *clone = NULL;
 
<------>if (acl) {
<------><------>int size = sizeof(struct posix_acl) + acl->a_count *
<------><------>           sizeof(struct posix_acl_entry);
<------><------>clone = kmemdup(acl, size, flags);
<------><------>if (clone)
<------><------><------>refcount_set(&clone->a_refcount, 1);
<------>}
<------>return clone;
}
 
/*
 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
 */
int
posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl)
{
<------>const struct posix_acl_entry *pa, *pe;
<------>int state = ACL_USER_OBJ;
<------>int needs_mask = 0;
 
<------>FOREACH_ACL_ENTRY(pa, acl, pe) {
<------><------>if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
<------><------><------>return -EINVAL;
<------><------>switch (pa->e_tag) {
<------><------><------>case ACL_USER_OBJ:
<------><------><------><------>if (state == ACL_USER_OBJ) {
<------><------><------><------><------>state = ACL_USER;
<------><------><------><------><------>break;
<------><------><------><------>}
<------><------><------><------>return -EINVAL;
 
<------><------><------>case ACL_USER:
<------><------><------><------>if (state != ACL_USER)
<------><------><------><------><------>return -EINVAL;
<------><------><------><------>if (!kuid_has_mapping(user_ns, pa->e_uid))
<------><------><------><------><------>return -EINVAL;
<------><------><------><------>needs_mask = 1;
<------><------><------><------>break;
 
<------><------><------>case ACL_GROUP_OBJ:
<------><------><------><------>if (state == ACL_USER) {
<------><------><------><------><------>state = ACL_GROUP;
<------><------><------><------><------>break;
<------><------><------><------>}
<------><------><------><------>return -EINVAL;
 
<------><------><------>case ACL_GROUP:
<------><------><------><------>if (state != ACL_GROUP)
<------><------><------><------><------>return -EINVAL;
<------><------><------><------>if (!kgid_has_mapping(user_ns, pa->e_gid))
<------><------><------><------><------>return -EINVAL;
<------><------><------><------>needs_mask = 1;
<------><------><------><------>break;
 
<------><------><------>case ACL_MASK:
<------><------><------><------>if (state != ACL_GROUP)
<------><------><------><------><------>return -EINVAL;
<------><------><------><------>state = ACL_OTHER;
<------><------><------><------>break;
 
<------><------><------>case ACL_OTHER:
<------><------><------><------>if (state == ACL_OTHER ||
<------><------><------><------>    (state == ACL_GROUP && !needs_mask)) {
<------><------><------><------><------>state = 0;
<------><------><------><------><------>break;
<------><------><------><------>}
<------><------><------><------>return -EINVAL;
 
<------><------><------>default:
<------><------><------><------>return -EINVAL;
<------><------>}
<------>}
<------>if (state == 0)
<------><------>return 0;
<------>return -EINVAL;
}
EXPORT_SYMBOL(posix_acl_valid);
 
/*
 * Returns 0 if the acl can be exactly represented in the traditional
 * file mode permission bits, or else 1. Returns -E... on error.
 */
int
posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
{
<------>const struct posix_acl_entry *pa, *pe;
<------>umode_t mode = 0;
<------>int not_equiv = 0;
 
<------>/*
<------> * A null ACL can always be presented as mode bits.
<------> */
<------>if (!acl)
<------><------>return 0;
 
<------>FOREACH_ACL_ENTRY(pa, acl, pe) {
<------><------>switch (pa->e_tag) {
<------><------><------>case ACL_USER_OBJ:
<------><------><------><------>mode |= (pa->e_perm & S_IRWXO) << 6;
<------><------><------><------>break;
<------><------><------>case ACL_GROUP_OBJ:
<------><------><------><------>mode |= (pa->e_perm & S_IRWXO) << 3;
<------><------><------><------>break;
<------><------><------>case ACL_OTHER:
<------><------><------><------>mode |= pa->e_perm & S_IRWXO;
<------><------><------><------>break;
<------><------><------>case ACL_MASK:
<------><------><------><------>mode = (mode & ~S_IRWXG) |
<------><------><------><------>       ((pa->e_perm & S_IRWXO) << 3);
<------><------><------><------>not_equiv = 1;
<------><------><------><------>break;
<------><------><------>case ACL_USER:
<------><------><------>case ACL_GROUP:
<------><------><------><------>not_equiv = 1;
<------><------><------><------>break;
<------><------><------>default:
<------><------><------><------>return -EINVAL;
<------><------>}
<------>}
        if (mode_p)
                *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
        return not_equiv;
}
EXPORT_SYMBOL(posix_acl_equiv_mode);
 
/*
 * Create an ACL representing the file mode permission bits of an inode.
 */
struct posix_acl *
posix_acl_from_mode(umode_t mode, gfp_t flags)
{
<------>struct posix_acl *acl = posix_acl_alloc(3, flags);
<------>if (!acl)
<------><------>return ERR_PTR(-ENOMEM);
 
<------>acl->a_entries[0].e_tag  = ACL_USER_OBJ;
<------>acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
 
<------>acl->a_entries[1].e_tag  = ACL_GROUP_OBJ;
<------>acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
 
<------>acl->a_entries[2].e_tag  = ACL_OTHER;
<------>acl->a_entries[2].e_perm = (mode & S_IRWXO);
<------>return acl;
}
EXPORT_SYMBOL(posix_acl_from_mode);
 
/*
 * Return 0 if current is granted want access to the inode
 * by the acl. Returns -E... otherwise.
 */
int
posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
{
<------>const struct posix_acl_entry *pa, *pe, *mask_obj;
<------>int found = 0;
 
<------>want &= MAY_READ | MAY_WRITE | MAY_EXEC;
 
<------>FOREACH_ACL_ENTRY(pa, acl, pe) {
                switch(pa->e_tag) {
                        case ACL_USER_OBJ:
<------><------><------><------>/* (May have been checked already) */
<------><------><------><------>if (uid_eq(inode->i_uid, current_fsuid()))
                                        goto check_perm;
                                break;
                        case ACL_USER:
<------><------><------><------>if (uid_eq(pa->e_uid, current_fsuid()))
                                        goto mask;
<------><------><------><------>break;
                        case ACL_GROUP_OBJ:
                                if (in_group_p(inode->i_gid)) {
<------><------><------><------><------>found = 1;
<------><------><------><------><------>if ((pa->e_perm & want) == want)
<------><------><------><------><------><------>goto mask;
                                }
<------><------><------><------>break;
                        case ACL_GROUP:
<------><------><------><------>if (in_group_p(pa->e_gid)) {
<------><------><------><------><------>found = 1;
<------><------><------><------><------>if ((pa->e_perm & want) == want)
<------><------><------><------><------><------>goto mask;
                                }
                                break;
                        case ACL_MASK:
                                break;
                        case ACL_OTHER:
<------><------><------><------>if (found)
<------><------><------><------><------>return -EACCES;
<------><------><------><------>else
<------><------><------><------><------>goto check_perm;
<------><------><------>default:
<------><------><------><------>return -EIO;
                }
        }
<------>return -EIO;
 
mask:
<------>for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
<------><------>if (mask_obj->e_tag == ACL_MASK) {
<------><------><------>if ((pa->e_perm & mask_obj->e_perm & want) == want)
<------><------><------><------>return 0;
<------><------><------>return -EACCES;
<------><------>}
<------>}
 
check_perm:
<------>if ((pa->e_perm & want) == want)
<------><------>return 0;
<------>return -EACCES;
}
 
/*
 * Modify acl when creating a new inode. The caller must ensure the acl is
 * only referenced once.
 *
 * mode_p initially must contain the mode parameter to the open() / creat()
 * system calls. All permissions that are not granted by the acl are removed.
 * The permissions in the acl are changed to reflect the mode_p parameter.
 */
static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
{
<------>struct posix_acl_entry *pa, *pe;
<------>struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
<------>umode_t mode = *mode_p;
<------>int not_equiv = 0;
 
<------>/* assert(atomic_read(acl->a_refcount) == 1); */
 
<------>FOREACH_ACL_ENTRY(pa, acl, pe) {
                switch(pa->e_tag) {
                        case ACL_USER_OBJ:
<------><------><------><------>pa->e_perm &= (mode >> 6) | ~S_IRWXO;
<------><------><------><------>mode &= (pa->e_perm << 6) | ~S_IRWXU;
<------><------><------><------>break;
 
<------><------><------>case ACL_USER:
<------><------><------>case ACL_GROUP:
<------><------><------><------>not_equiv = 1;
<------><------><------><------>break;
 
                        case ACL_GROUP_OBJ:
<------><------><------><------>group_obj = pa;
                                break;
 
                        case ACL_OTHER:
<------><------><------><------>pa->e_perm &= mode | ~S_IRWXO;
<------><------><------><------>mode &= pa->e_perm | ~S_IRWXO;
                                break;
 
                        case ACL_MASK:
<------><------><------><------>mask_obj = pa;
<------><------><------><------>not_equiv = 1;
                                break;
 
<------><------><------>default:
<------><------><------><------>return -EIO;
                }
        }
 
<------>if (mask_obj) {
<------><------>mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
<------><------>mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
<------>} else {
<------><------>if (!group_obj)
<------><------><------>return -EIO;
<------><------>group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
<------><------>mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
<------>}
 
<------>*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
        return not_equiv;
}
 
/*
 * Modify the ACL for the chmod syscall.
 */
static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
{
<------>struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
<------>struct posix_acl_entry *pa, *pe;
 
<------>/* assert(atomic_read(acl->a_refcount) == 1); */
 
<------>FOREACH_ACL_ENTRY(pa, acl, pe) {
<------><------>switch(pa->e_tag) {
<------><------><------>case ACL_USER_OBJ:
<------><------><------><------>pa->e_perm = (mode & S_IRWXU) >> 6;
<------><------><------><------>break;
 
<------><------><------>case ACL_USER:
<------><------><------>case ACL_GROUP:
<------><------><------><------>break;
 
<------><------><------>case ACL_GROUP_OBJ:
<------><------><------><------>group_obj = pa;
<------><------><------><------>break;
 
<------><------><------>case ACL_MASK:
<------><------><------><------>mask_obj = pa;
<------><------><------><------>break;
 
<------><------><------>case ACL_OTHER:
<------><------><------><------>pa->e_perm = (mode & S_IRWXO);
<------><------><------><------>break;
 
<------><------><------>default:
<------><------><------><------>return -EIO;
<------><------>}
<------>}
 
<------>if (mask_obj) {
<------><------>mask_obj->e_perm = (mode & S_IRWXG) >> 3;
<------>} else {
<------><------>if (!group_obj)
<------><------><------>return -EIO;
<------><------>group_obj->e_perm = (mode & S_IRWXG) >> 3;
<------>}
 
<------>return 0;
}
 
int
__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
{
<------>struct posix_acl *clone = posix_acl_clone(*acl, gfp);
<------>int err = -ENOMEM;
<------>if (clone) {
<------><------>err = posix_acl_create_masq(clone, mode_p);
<------><------>if (err < 0) {
<------><------><------>posix_acl_release(clone);
<------><------><------>clone = NULL;
<------><------>}
<------>}
<------>posix_acl_release(*acl);
<------>*acl = clone;
<------>return err;
}
EXPORT_SYMBOL(__posix_acl_create);
 
int
__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
{
<------>struct posix_acl *clone = posix_acl_clone(*acl, gfp);
<------>int err = -ENOMEM;
<------>if (clone) {
<------><------>err = __posix_acl_chmod_masq(clone, mode);
<------><------>if (err) {
<------><------><------>posix_acl_release(clone);
<------><------><------>clone = NULL;
<------><------>}
<------>}
<------>posix_acl_release(*acl);
<------>*acl = clone;
<------>return err;
}
EXPORT_SYMBOL(__posix_acl_chmod);
 
int
posix_acl_chmod(struct inode *inode, umode_t mode)
{
<------>struct posix_acl *acl;
<------>int ret = 0;
 
<------>if (!IS_POSIXACL(inode))
<------><------>return 0;
<------>if (!inode->i_op->set_acl)
<------><------>return -EOPNOTSUPP;
 
<------>acl = get_acl(inode, ACL_TYPE_ACCESS);
<------>if (IS_ERR_OR_NULL(acl)) {
<------><------>if (acl == ERR_PTR(-EOPNOTSUPP))
<------><------><------>return 0;
<------><------>return PTR_ERR(acl);
<------>}
 
<------>ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
<------>if (ret)
<------><------>return ret;
<------>ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS);
<------>posix_acl_release(acl);
<------>return ret;
}
EXPORT_SYMBOL(posix_acl_chmod);
 
int
posix_acl_create(struct inode *dir, umode_t *mode,
<------><------>struct posix_acl **default_acl, struct posix_acl **acl)
{
<------>struct posix_acl *p;
<------>struct posix_acl *clone;
<------>int ret;
 
<------>*acl = NULL;
<------>*default_acl = NULL;
 
<------>if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
<------><------>return 0;
 
<------>p = get_acl(dir, ACL_TYPE_DEFAULT);
<------>if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
<------><------>*mode &= ~current_umask();
<------><------>return 0;
<------>}
<------>if (IS_ERR(p))
<------><------>return PTR_ERR(p);
 
<------>ret = -ENOMEM;
<------>clone = posix_acl_clone(p, GFP_NOFS);
<------>if (!clone)
<------><------>goto err_release;
 
<------>ret = posix_acl_create_masq(clone, mode);
<------>if (ret < 0)
<------><------>goto err_release_clone;
 
<------>if (ret == 0)
<------><------>posix_acl_release(clone);
<------>else
<------><------>*acl = clone;
 
<------>if (!S_ISDIR(*mode))
<------><------>posix_acl_release(p);
<------>else
<------><------>*default_acl = p;
 
<------>return 0;
 
err_release_clone:
<------>posix_acl_release(clone);
err_release:
<------>posix_acl_release(p);
<------>return ret;
}
EXPORT_SYMBOL_GPL(posix_acl_create);
 
/**
 * posix_acl_update_mode  -  update mode in set_acl
 * @inode: target inode
 * @mode_p: mode (pointer) for update
 * @acl: acl pointer
 *
 * Update the file mode when setting an ACL: compute the new file permission
 * bits based on the ACL.  In addition, if the ACL is equivalent to the new
 * file mode, set *@acl to NULL to indicate that no ACL should be set.
 *
 * As with chmod, clear the setgid bit if the caller is not in the owning group
 * or capable of CAP_FSETID (see inode_change_ok).
 *
 * Called from set_acl inode operations.
 */
int posix_acl_update_mode(struct inode *inode, umode_t *mode_p,
<------><------><------>  struct posix_acl **acl)
{
<------>umode_t mode = inode->i_mode;
<------>int error;
 
<------>error = posix_acl_equiv_mode(*acl, &mode);
<------>if (error < 0)
<------><------>return error;
<------>if (error == 0)
<------><------>*acl = NULL;
<------>if (!in_group_p(inode->i_gid) &&
<------>    !capable_wrt_inode_uidgid(inode, CAP_FSETID))
<------><------>mode &= ~S_ISGID;
<------>*mode_p = mode;
<------>return 0;
}
EXPORT_SYMBOL(posix_acl_update_mode);
 
/*
 * Fix up the uids and gids in posix acl extended attributes in place.
 */
static void posix_acl_fix_xattr_userns(
<------>struct user_namespace *to, struct user_namespace *from,
<------>void *value, size_t size)
{
<------>struct posix_acl_xattr_header *header = value;
<------>struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end;
<------>int count;
<------>kuid_t uid;
<------>kgid_t gid;
 
<------>if (!value)
<------><------>return;
<------>if (size < sizeof(struct posix_acl_xattr_header))
<------><------>return;
<------>if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
<------><------>return;
 
<------>count = posix_acl_xattr_count(size);
<------>if (count < 0)
<------><------>return;
<------>if (count == 0)
<------><------>return;
 
<------>for (end = entry + count; entry != end; entry++) {
<------><------>switch(le16_to_cpu(entry->e_tag)) {
<------><------>case ACL_USER:
<------><------><------>uid = make_kuid(from, le32_to_cpu(entry->e_id));
<------><------><------>entry->e_id = cpu_to_le32(from_kuid(to, uid));
<------><------><------>break;
<------><------>case ACL_GROUP:
<------><------><------>gid = make_kgid(from, le32_to_cpu(entry->e_id));
<------><------><------>entry->e_id = cpu_to_le32(from_kgid(to, gid));
<------><------><------>break;
<------><------>default:
<------><------><------>break;
<------><------>}
<------>}
}
 
void posix_acl_fix_xattr_from_user(void *value, size_t size)
{
<------>struct user_namespace *user_ns = current_user_ns();
<------>if (user_ns == &init_user_ns)
<------><------>return;
<------>posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
}
 
void posix_acl_fix_xattr_to_user(void *value, size_t size)
{
<------>struct user_namespace *user_ns = current_user_ns();
<------>if (user_ns == &init_user_ns)
<------><------>return;
<------>posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
}
 
/*
 * Convert from extended attribute to in-memory representation.
 */
struct posix_acl *
posix_acl_from_xattr(struct user_namespace *user_ns,
<------><------>     const void *value, size_t size)
{
<------>const struct posix_acl_xattr_header *header = value;
<------>const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end;
<------>int count;
<------>struct posix_acl *acl;
<------>struct posix_acl_entry *acl_e;
 
<------>if (!value)
<------><------>return NULL;
<------>if (size < sizeof(struct posix_acl_xattr_header))
<------><------> return ERR_PTR(-EINVAL);
<------>if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
<------><------>return ERR_PTR(-EOPNOTSUPP);
 
<------>count = posix_acl_xattr_count(size);
<------>if (count < 0)
<------><------>return ERR_PTR(-EINVAL);
<------>if (count == 0)
<------><------>return NULL;
<------>
<------>acl = posix_acl_alloc(count, GFP_NOFS);
<------>if (!acl)
<------><------>return ERR_PTR(-ENOMEM);
<------>acl_e = acl->a_entries;
<------>
<------>for (end = entry + count; entry != end; acl_e++, entry++) {
<------><------>acl_e->e_tag  = le16_to_cpu(entry->e_tag);
<------><------>acl_e->e_perm = le16_to_cpu(entry->e_perm);
 
<------><------>switch(acl_e->e_tag) {
<------><------><------>case ACL_USER_OBJ:
<------><------><------>case ACL_GROUP_OBJ:
<------><------><------>case ACL_MASK:
<------><------><------>case ACL_OTHER:
<------><------><------><------>break;
 
<------><------><------>case ACL_USER:
<------><------><------><------>acl_e->e_uid =
<------><------><------><------><------>make_kuid(user_ns,
<------><------><------><------><------><------>  le32_to_cpu(entry->e_id));
<------><------><------><------>if (!uid_valid(acl_e->e_uid))
<------><------><------><------><------>goto fail;
<------><------><------><------>break;
<------><------><------>case ACL_GROUP:
<------><------><------><------>acl_e->e_gid =
<------><------><------><------><------>make_kgid(user_ns,
<------><------><------><------><------><------>  le32_to_cpu(entry->e_id));
<------><------><------><------>if (!gid_valid(acl_e->e_gid))
<------><------><------><------><------>goto fail;
<------><------><------><------>break;
 
<------><------><------>default:
<------><------><------><------>goto fail;
<------><------>}
<------>}
<------>return acl;
 
fail:
<------>posix_acl_release(acl);
<------>return ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL (posix_acl_from_xattr);
 
/*
 * Convert from in-memory to extended attribute representation.
 */
int
posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
<------><------>   void *buffer, size_t size)
{
<------>struct posix_acl_xattr_header *ext_acl = buffer;
<------>struct posix_acl_xattr_entry *ext_entry;
<------>int real_size, n;
 
<------>real_size = posix_acl_xattr_size(acl->a_count);
<------>if (!buffer)
<------><------>return real_size;
<------>if (real_size > size)
<------><------>return -ERANGE;
 
<------>ext_entry = (void *)(ext_acl + 1);
<------>ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
 
<------>for (n=0; n < acl->a_count; n++, ext_entry++) {
<------><------>const struct posix_acl_entry *acl_e = &acl->a_entries[n];
<------><------>ext_entry->e_tag  = cpu_to_le16(acl_e->e_tag);
<------><------>ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
<------><------>switch(acl_e->e_tag) {
<------><------>case ACL_USER:
<------><------><------>ext_entry->e_id =
<------><------><------><------>cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
<------><------><------>break;
<------><------>case ACL_GROUP:
<------><------><------>ext_entry->e_id =
<------><------><------><------>cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
<------><------><------>break;
<------><------>default:
<------><------><------>ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
<------><------><------>break;
<------><------>}
<------>}
<------>return real_size;
}
EXPORT_SYMBOL (posix_acl_to_xattr);
 
static int
posix_acl_xattr_get(const struct xattr_handler *handler,
<------><------>    struct dentry *unused, struct inode *inode,
<------><------>    const char *name, void *value, size_t size, int flags)
{
<------>struct posix_acl *acl;
<------>int error;
 
<------>if (!IS_POSIXACL(inode))
<------><------>return -EOPNOTSUPP;
<------>if (S_ISLNK(inode->i_mode))
<------><------>return -EOPNOTSUPP;
 
<------>acl = get_acl(inode, handler->flags);
<------>if (IS_ERR(acl))
<------><------>return PTR_ERR(acl);
<------>if (acl == NULL)
<------><------>return -ENODATA;
 
<------>error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
<------>posix_acl_release(acl);
 
<------>return error;
}
 
int
set_posix_acl(struct inode *inode, int type, struct posix_acl *acl)
{
<------>if (!IS_POSIXACL(inode))
<------><------>return -EOPNOTSUPP;
<------>if (!inode->i_op->set_acl)
<------><------>return -EOPNOTSUPP;
 
<------>if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
<------><------>return acl ? -EACCES : 0;
<------>if (!inode_owner_or_capable(inode))
<------><------>return -EPERM;
 
<------>if (acl) {
<------><------>int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl);
<------><------>if (ret)
<------><------><------>return ret;
<------>}
<------>return inode->i_op->set_acl(inode, acl, type);
}
EXPORT_SYMBOL(set_posix_acl);
 
static int
posix_acl_xattr_set(const struct xattr_handler *handler,
<------><------>    struct dentry *unused, struct inode *inode,
<------><------>    const char *name, const void *value,
<------><------>    size_t size, int flags)
{
<------>struct posix_acl *acl = NULL;
<------>int ret;
 
<------>if (value) {
<------><------>acl = posix_acl_from_xattr(&init_user_ns, value, size);
<------><------>if (IS_ERR(acl))
<------><------><------>return PTR_ERR(acl);
<------>}
<------>ret = set_posix_acl(inode, handler->flags, acl);
<------>posix_acl_release(acl);
<------>return ret;
}
 
static bool
posix_acl_xattr_list(struct dentry *dentry)
{
<------>return IS_POSIXACL(d_backing_inode(dentry));
}
 
const struct xattr_handler posix_acl_access_xattr_handler = {
<------>.name = XATTR_NAME_POSIX_ACL_ACCESS,
<------>.flags = ACL_TYPE_ACCESS,
<------>.list = posix_acl_xattr_list,
<------>.get = posix_acl_xattr_get,
<------>.set = posix_acl_xattr_set,
};
EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
 
const struct xattr_handler posix_acl_default_xattr_handler = {
<------>.name = XATTR_NAME_POSIX_ACL_DEFAULT,
<------>.flags = ACL_TYPE_DEFAULT,
<------>.list = posix_acl_xattr_list,
<------>.get = posix_acl_xattr_get,
<------>.set = posix_acl_xattr_set,
};
EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
 
int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
<------>int error;
 
<------>if (type == ACL_TYPE_ACCESS) {
<------><------>error = posix_acl_update_mode(inode,
<------><------><------><------>&inode->i_mode, &acl);
<------><------>if (error)
<------><------><------>return error;
<------>}
 
<------>inode->i_ctime = current_time(inode);
<------>set_cached_acl(inode, type, acl);
<------>return 0;
}
 
int simple_acl_create(struct inode *dir, struct inode *inode)
{
<------>struct posix_acl *default_acl, *acl;
<------>int error;
 
<------>error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
<------>if (error)
<------><------>return error;
 
<------>set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
<------>set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
 
<------>if (default_acl)
<------><------>posix_acl_release(default_acl);
<------>if (acl)
<------><------>posix_acl_release(acl);
<------>return 0;
}