[linux.git] / fs / posix_acl.c

/*
 * Copyright (C) 2002,2003 by Andreas Gruenbacher <[email protected]>
 *
 * Fixes from William Schumacher incorporated on 15 March 2001.
 *    (Reported by Charles Bertsch, <[email protected]>).
 */

/*
 *  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/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
#include <linux/export.h>
#include <linux/user_namespace.h>

EXPORT_SYMBOL(posix_acl_init);
EXPORT_SYMBOL(posix_acl_alloc);
EXPORT_SYMBOL(posix_acl_valid);
EXPORT_SYMBOL(posix_acl_equiv_mode);
EXPORT_SYMBOL(posix_acl_from_mode);

struct posix_acl *get_acl(struct inode *inode, int type)
{
	struct posix_acl *acl;

	acl = get_cached_acl(inode, type);
	if (acl != ACL_NOT_CACHED)
		return acl;

	if (!IS_POSIXACL(inode))
		return NULL;

	/*
	 * A filesystem can force a ACL callback by just never filling the
	 * ACL cache. But normally you'd fill the cache either at inode
	 * instantiation time, or on the first ->get_acl call.
	 *
	 * 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;
	}
	return inode->i_op->get_acl(inode, type);
}
EXPORT_SYMBOL(get_acl);

/*
 * Init a fresh posix_acl
 */
void
posix_acl_init(struct posix_acl *acl, int count)
{
	atomic_set(&acl->a_refcount, 1);
	acl->a_count = count;
}

/*
 * 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;
}

/*
 * 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)
			atomic_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(const struct posix_acl *acl)
{
	const struct posix_acl_entry *pa, *pe;
	int state = ACL_USER_OBJ;
	kuid_t prev_uid = INVALID_UID;
	kgid_t prev_gid = INVALID_GID;
	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 (!uid_valid(pa->e_uid))
					return -EINVAL;
				if (uid_valid(prev_uid) &&
				    uid_lte(pa->e_uid, prev_uid))
					return -EINVAL;
				prev_uid = pa->e_uid;
				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 (!gid_valid(pa->e_gid))
					return -EINVAL;
				if (gid_valid(prev_gid) &&
				    gid_lte(pa->e_gid, prev_gid))
					return -EINVAL;
				prev_gid = pa->e_gid;
				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;
}

/*
 * 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;

	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;
}

/*
 * 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;
}

/*
 * 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 | MAY_NOT_BLOCK;

	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))
		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;
	int ret;

	if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
		goto no_acl;

	p = get_acl(dir, ACL_TYPE_DEFAULT);
	if (IS_ERR(p))
		return PTR_ERR(p);

	if (!p) {
		*mode &= ~current_umask();
		goto no_acl;
	}

	*acl = posix_acl_clone(p, GFP_NOFS);
	if (!*acl)
		return -ENOMEM;

	ret = posix_acl_create_masq(*acl, mode);
	if (ret < 0) {
		posix_acl_release(*acl);
		return -ENOMEM;
	}

	if (ret == 0) {
		posix_acl_release(*acl);
		*acl = NULL;
	}

	if (!S_ISDIR(*mode)) {
		posix_acl_release(p);
		*default_acl = NULL;
	} else {
		*default_acl = p;
	}
	return 0;

no_acl:
	*default_acl = NULL;
	*acl = NULL;
	return 0;
}
EXPORT_SYMBOL_GPL(posix_acl_create);

/*
 * 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)
{
	posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
	posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
	int count;
	kuid_t uid;
	kgid_t gid;

	if (!value)
		return;
	if (size < sizeof(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)
{
	posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
	posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
	int count;
	struct posix_acl *acl;
	struct posix_acl_entry *acl_e;

	if (!value)
		return NULL;
	if (size < sizeof(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)
{
	posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
	posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
	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_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(struct dentry *dentry, const char *name,
		void *value, size_t size, int type)
{
	struct posix_acl *acl;
	int error;

	if (!IS_POSIXACL(dentry->d_inode))
		return -EOPNOTSUPP;
	if (S_ISLNK(dentry->d_inode->i_mode))
		return -EOPNOTSUPP;

	acl = get_acl(dentry->d_inode, type);
	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;
}

static int
posix_acl_xattr_set(struct dentry *dentry, const char *name,
		const void *value, size_t size, int flags, int type)
{
	struct inode *inode = dentry->d_inode;
	struct posix_acl *acl = NULL;
	int ret;

	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 value ? -EACCES : 0;
	if (!inode_owner_or_capable(inode))
		return -EPERM;

	if (value) {
		acl = posix_acl_from_xattr(&init_user_ns, value, size);
		if (IS_ERR(acl))
			return PTR_ERR(acl);

		if (acl) {
			ret = posix_acl_valid(acl);
			if (ret)
				goto out;
		}
	}

	ret = inode->i_op->set_acl(inode, acl, type);
out:
	posix_acl_release(acl);
	return ret;
}

static size_t
posix_acl_xattr_list(struct dentry *dentry, char *list, size_t list_size,
		const char *name, size_t name_len, int type)
{
	const char *xname;
	size_t size;

	if (!IS_POSIXACL(dentry->d_inode))
		return -EOPNOTSUPP;
	if (S_ISLNK(dentry->d_inode->i_mode))
		return -EOPNOTSUPP;

	if (type == ACL_TYPE_ACCESS)
		xname = POSIX_ACL_XATTR_ACCESS;
	else
		xname = POSIX_ACL_XATTR_DEFAULT;

	size = strlen(xname) + 1;
	if (list && size <= list_size)
		memcpy(list, xname, size);
	return size;
}

const struct xattr_handler posix_acl_access_xattr_handler = {
	.prefix = POSIX_ACL_XATTR_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 = {
	.prefix = POSIX_ACL_XATTR_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_equiv_mode(acl, &inode->i_mode);
		if (error < 0)
			return 0;
		if (error == 0)
			acl = NULL;
	}

	inode->i_ctime = CURRENT_TIME;
	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;
}
Commit	Line	Data
1da177e4	1	/*
5c8ebd57	2	* Copyright (C) 2002,2003 by Andreas Gruenbacher <[email protected]>
1da177e4	3	*
5c8ebd57 CH	4	* Fixes from William Schumacher incorporated on 15 March 2001.
5c8ebd57 CH	5	* (Reported by Charles Bertsch, <[email protected]>).
1da177e4 LT	6	*/
	7
	8	/*
	9	* This file contains generic functions for manipulating
	10	* POSIX 1003.1e draft standard 17 ACLs.
	11	*/
	12
	13	#include <linux/kernel.h>
	14	#include <linux/slab.h>
60063497	15	#include <linux/atomic.h>
1da177e4 LT	16	#include <linux/fs.h>
	17	#include <linux/sched.h>
	18	#include <linux/posix_acl.h>
5c8ebd57	19	#include <linux/posix_acl_xattr.h>
2aeccbe9	20	#include <linux/xattr.h>
630d9c47	21	#include <linux/export.h>
5c8ebd57	22	#include <linux/user_namespace.h>
1da177e4	23
f61f6da0	24	EXPORT_SYMBOL(posix_acl_init);
1da177e4	25	EXPORT_SYMBOL(posix_acl_alloc);
1da177e4 LT	26	EXPORT_SYMBOL(posix_acl_valid);
	27	EXPORT_SYMBOL(posix_acl_equiv_mode);
	28	EXPORT_SYMBOL(posix_acl_from_mode);
1da177e4	29
2982baa2 CH	30	struct posix_acl get_acl(struct inode inode, int type)
	31	{
	32	struct posix_acl *acl;
	33
	34	acl = get_cached_acl(inode, type);
	35	if (acl != ACL_NOT_CACHED)
	36	return acl;
	37
	38	if (!IS_POSIXACL(inode))
	39	return NULL;
	40
	41	/*
	42	* A filesystem can force a ACL callback by just never filling the
	43	* ACL cache. But normally you'd fill the cache either at inode
	44	* instantiation time, or on the first ->get_acl call.
	45	*
	46	* If the filesystem doesn't have a get_acl() function at all, we'll
	47	* just create the negative cache entry.
	48	*/
	49	if (!inode->i_op->get_acl) {
	50	set_cached_acl(inode, type, NULL);
	51	return NULL;
	52	}
	53	return inode->i_op->get_acl(inode, type);
	54	}
	55	EXPORT_SYMBOL(get_acl);
	56
f61f6da0 CL	57	/*
	58	* Init a fresh posix_acl
	59	*/
	60	void
	61	posix_acl_init(struct posix_acl *acl, int count)
	62	{
	63	atomic_set(&acl->a_refcount, 1);
	64	acl->a_count = count;
	65	}
	66
1da177e4 LT	67	/*
	68	* Allocate a new ACL with the specified number of entries.
	69	*/
	70	struct posix_acl *
dd0fc66f	71	posix_acl_alloc(int count, gfp_t flags)
1da177e4 LT	72	{
	73	const size_t size = sizeof(struct posix_acl) +
	74	count * sizeof(struct posix_acl_entry);
	75	struct posix_acl *acl = kmalloc(size, flags);
f61f6da0 CL	76	if (acl)
f61f6da0 CL	77	posix_acl_init(acl, count);
1da177e4 LT	78	return acl;
	79	}
	80
	81	/*
	82	* Clone an ACL.
	83	*/
edde854e	84	static struct posix_acl *
dd0fc66f	85	posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
1da177e4 LT	86	{
	87	struct posix_acl *clone = NULL;
	88
	89	if (acl) {
	90	int size = sizeof(struct posix_acl) + acl->a_count *
	91	sizeof(struct posix_acl_entry);
52978be6 AD	92	clone = kmemdup(acl, size, flags);
52978be6 AD	93	if (clone)
1da177e4	94	atomic_set(&clone->a_refcount, 1);
1da177e4 LT	95	}
	96	return clone;
	97	}
	98
	99	/*
	100	* Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
	101	*/
	102	int
	103	posix_acl_valid(const struct posix_acl *acl)
	104	{
	105	const struct posix_acl_entry pa, pe;
	106	int state = ACL_USER_OBJ;
2f6f0654 EB	107	kuid_t prev_uid = INVALID_UID;
2f6f0654 EB	108	kgid_t prev_gid = INVALID_GID;
1da177e4 LT	109	int needs_mask = 0;
	110
	111	FOREACH_ACL_ENTRY(pa, acl, pe) {
	112	if (pa->e_perm & ~(ACL_READ\|ACL_WRITE\|ACL_EXECUTE))
	113	return -EINVAL;
	114	switch (pa->e_tag) {
	115	case ACL_USER_OBJ:
	116	if (state == ACL_USER_OBJ) {
1da177e4 LT	117	state = ACL_USER;
	118	break;
	119	}
	120	return -EINVAL;
	121
	122	case ACL_USER:
	123	if (state != ACL_USER)
	124	return -EINVAL;
2f6f0654	125	if (!uid_valid(pa->e_uid))
1da177e4	126	return -EINVAL;
2f6f0654 EB	127	if (uid_valid(prev_uid) &&
	128	uid_lte(pa->e_uid, prev_uid))
	129	return -EINVAL;
	130	prev_uid = pa->e_uid;
1da177e4 LT	131	needs_mask = 1;
	132	break;
	133
	134	case ACL_GROUP_OBJ:
	135	if (state == ACL_USER) {
1da177e4 LT	136	state = ACL_GROUP;
	137	break;
	138	}
	139	return -EINVAL;
	140
	141	case ACL_GROUP:
	142	if (state != ACL_GROUP)
	143	return -EINVAL;
2f6f0654 EB	144	if (!gid_valid(pa->e_gid))
	145	return -EINVAL;
	146	if (gid_valid(prev_gid) &&
	147	gid_lte(pa->e_gid, prev_gid))
1da177e4	148	return -EINVAL;
2f6f0654	149	prev_gid = pa->e_gid;
1da177e4 LT	150	needs_mask = 1;
	151	break;
	152
	153	case ACL_MASK:
	154	if (state != ACL_GROUP)
	155	return -EINVAL;
	156	state = ACL_OTHER;
	157	break;
	158
	159	case ACL_OTHER:
	160	if (state == ACL_OTHER \|\|
	161	(state == ACL_GROUP && !needs_mask)) {
	162	state = 0;
	163	break;
	164	}
	165	return -EINVAL;
	166
	167	default:
	168	return -EINVAL;
	169	}
	170	}
	171	if (state == 0)
	172	return 0;
	173	return -EINVAL;
	174	}
	175
	176	/*
	177	* Returns 0 if the acl can be exactly represented in the traditional
	178	* file mode permission bits, or else 1. Returns -E... on error.
	179	*/
	180	int
d6952123	181	posix_acl_equiv_mode(const struct posix_acl acl, umode_t mode_p)
1da177e4 LT	182	{
1da177e4 LT	183	const struct posix_acl_entry pa, pe;
d6952123	184	umode_t mode = 0;
1da177e4 LT	185	int not_equiv = 0;
	186
	187	FOREACH_ACL_ENTRY(pa, acl, pe) {
	188	switch (pa->e_tag) {
	189	case ACL_USER_OBJ:
	190	mode \|= (pa->e_perm & S_IRWXO) << 6;
	191	break;
	192	case ACL_GROUP_OBJ:
	193	mode \|= (pa->e_perm & S_IRWXO) << 3;
	194	break;
	195	case ACL_OTHER:
	196	mode \|= pa->e_perm & S_IRWXO;
	197	break;
	198	case ACL_MASK:
	199	mode = (mode & ~S_IRWXG) \|
	200	((pa->e_perm & S_IRWXO) << 3);
	201	not_equiv = 1;
	202	break;
	203	case ACL_USER:
	204	case ACL_GROUP:
	205	not_equiv = 1;
	206	break;
	207	default:
	208	return -EINVAL;
	209	}
	210	}
	211	if (mode_p)
	212	mode_p = (mode_p & ~S_IRWXUGO) \| mode;
	213	return not_equiv;
	214	}
	215
	216	/*
	217	* Create an ACL representing the file mode permission bits of an inode.
	218	*/
	219	struct posix_acl *
3a5fba19	220	posix_acl_from_mode(umode_t mode, gfp_t flags)
1da177e4 LT	221	{
	222	struct posix_acl *acl = posix_acl_alloc(3, flags);
	223	if (!acl)
	224	return ERR_PTR(-ENOMEM);
	225
	226	acl->a_entries[0].e_tag = ACL_USER_OBJ;
1da177e4 LT	227	acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
	228
	229	acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
1da177e4 LT	230	acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
	231
	232	acl->a_entries[2].e_tag = ACL_OTHER;
1da177e4 LT	233	acl->a_entries[2].e_perm = (mode & S_IRWXO);
	234	return acl;
	235	}
	236
	237	/*
	238	* Return 0 if current is granted want access to the inode
	239	* by the acl. Returns -E... otherwise.
	240	*/
	241	int
	242	posix_acl_permission(struct inode inode, const struct posix_acl acl, int want)
	243	{
	244	const struct posix_acl_entry pa, pe, *mask_obj;
	245	int found = 0;
	246
d124b60a AG	247	want &= MAY_READ \| MAY_WRITE \| MAY_EXEC \| MAY_NOT_BLOCK;
d124b60a AG	248
1da177e4 LT	249	FOREACH_ACL_ENTRY(pa, acl, pe) {
	250	switch(pa->e_tag) {
	251	case ACL_USER_OBJ:
	252	/* (May have been checked already) */
2f6f0654	253	if (uid_eq(inode->i_uid, current_fsuid()))
1da177e4 LT	254	goto check_perm;
	255	break;
	256	case ACL_USER:
2f6f0654	257	if (uid_eq(pa->e_uid, current_fsuid()))
1da177e4 LT	258	goto mask;
	259	break;
	260	case ACL_GROUP_OBJ:
	261	if (in_group_p(inode->i_gid)) {
	262	found = 1;
	263	if ((pa->e_perm & want) == want)
	264	goto mask;
	265	}
	266	break;
	267	case ACL_GROUP:
2f6f0654	268	if (in_group_p(pa->e_gid)) {
1da177e4 LT	269	found = 1;
	270	if ((pa->e_perm & want) == want)
	271	goto mask;
	272	}
	273	break;
	274	case ACL_MASK:
	275	break;
	276	case ACL_OTHER:
	277	if (found)
	278	return -EACCES;
	279	else
	280	goto check_perm;
	281	default:
	282	return -EIO;
	283	}
	284	}
	285	return -EIO;
	286
	287	mask:
	288	for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
	289	if (mask_obj->e_tag == ACL_MASK) {
	290	if ((pa->e_perm & mask_obj->e_perm & want) == want)
	291	return 0;
	292	return -EACCES;
	293	}
	294	}
	295
	296	check_perm:
	297	if ((pa->e_perm & want) == want)
	298	return 0;
	299	return -EACCES;
	300	}
	301
	302	/*
	303	* Modify acl when creating a new inode. The caller must ensure the acl is
	304	* only referenced once.
	305	*
	306	* mode_p initially must contain the mode parameter to the open() / creat()
	307	* system calls. All permissions that are not granted by the acl are removed.
	308	* The permissions in the acl are changed to reflect the mode_p parameter.
	309	*/
d3fb6120	310	static int posix_acl_create_masq(struct posix_acl acl, umode_t mode_p)
1da177e4 LT	311	{
	312	struct posix_acl_entry pa, pe;
	313	struct posix_acl_entry group_obj = NULL, mask_obj = NULL;
d3fb6120	314	umode_t mode = *mode_p;
1da177e4 LT	315	int not_equiv = 0;
	316
	317	/* assert(atomic_read(acl->a_refcount) == 1); */
	318
	319	FOREACH_ACL_ENTRY(pa, acl, pe) {
	320	switch(pa->e_tag) {
	321	case ACL_USER_OBJ:
	322	pa->e_perm &= (mode >> 6) \| ~S_IRWXO;
	323	mode &= (pa->e_perm << 6) \| ~S_IRWXU;
	324	break;
	325
	326	case ACL_USER:
	327	case ACL_GROUP:
	328	not_equiv = 1;
	329	break;
	330
	331	case ACL_GROUP_OBJ:
	332	group_obj = pa;
	333	break;
	334
	335	case ACL_OTHER:
	336	pa->e_perm &= mode \| ~S_IRWXO;
	337	mode &= pa->e_perm \| ~S_IRWXO;
	338	break;
	339
	340	case ACL_MASK:
	341	mask_obj = pa;
	342	not_equiv = 1;
	343	break;
	344
	345	default:
	346	return -EIO;
	347	}
	348	}
	349
	350	if (mask_obj) {
	351	mask_obj->e_perm &= (mode >> 3) \| ~S_IRWXO;
	352	mode &= (mask_obj->e_perm << 3) \| ~S_IRWXG;
	353	} else {
	354	if (!group_obj)
	355	return -EIO;
	356	group_obj->e_perm &= (mode >> 3) \| ~S_IRWXO;
	357	mode &= (group_obj->e_perm << 3) \| ~S_IRWXG;
	358	}
	359
	360	mode_p = (mode_p & ~S_IRWXUGO) \| mode;
	361	return not_equiv;
	362	}
	363
	364	/*
	365	* Modify the ACL for the chmod syscall.
	366	*/
5bf3258f	367	static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
1da177e4 LT	368	{
	369	struct posix_acl_entry group_obj = NULL, mask_obj = NULL;
	370	struct posix_acl_entry pa, pe;
	371
	372	/* assert(atomic_read(acl->a_refcount) == 1); */
	373
	374	FOREACH_ACL_ENTRY(pa, acl, pe) {
	375	switch(pa->e_tag) {
	376	case ACL_USER_OBJ:
	377	pa->e_perm = (mode & S_IRWXU) >> 6;
	378	break;
	379
	380	case ACL_USER:
	381	case ACL_GROUP:
	382	break;
	383
	384	case ACL_GROUP_OBJ:
	385	group_obj = pa;
	386	break;
	387
	388	case ACL_MASK:
	389	mask_obj = pa;
	390	break;
	391
	392	case ACL_OTHER:
	393	pa->e_perm = (mode & S_IRWXO);
	394	break;
	395
	396	default:
	397	return -EIO;
	398	}
	399	}
	400
	401	if (mask_obj) {
	402	mask_obj->e_perm = (mode & S_IRWXG) >> 3;
	403	} else {
	404	if (!group_obj)
	405	return -EIO;
	406	group_obj->e_perm = (mode & S_IRWXG) >> 3;
	407	}
	408
	409	return 0;
	410	}
bc26ab5f	411
826cae2f	412	int
37bc1539	413	__posix_acl_create(struct posix_acl *acl, gfp_t gfp, umode_t mode_p)
826cae2f AV	414	{
	415	struct posix_acl clone = posix_acl_clone(acl, gfp);
	416	int err = -ENOMEM;
	417	if (clone) {
	418	err = posix_acl_create_masq(clone, mode_p);
	419	if (err < 0) {
	420	posix_acl_release(clone);
	421	clone = NULL;
	422	}
	423	}
	424	posix_acl_release(*acl);
	425	*acl = clone;
	426	return err;
	427	}
37bc1539	428	EXPORT_SYMBOL(__posix_acl_create);
826cae2f	429
bc26ab5f	430	int
5bf3258f	431	__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
bc26ab5f AV	432	{
	433	struct posix_acl clone = posix_acl_clone(acl, gfp);
	434	int err = -ENOMEM;
	435	if (clone) {
5bf3258f	436	err = __posix_acl_chmod_masq(clone, mode);
bc26ab5f AV	437	if (err) {
	438	posix_acl_release(clone);
	439	clone = NULL;
	440	}
	441	}
	442	posix_acl_release(*acl);
	443	*acl = clone;
	444	return err;
	445	}
5bf3258f CH	446	EXPORT_SYMBOL(__posix_acl_chmod);
	447
	448	int
37bc1539	449	posix_acl_chmod(struct inode *inode, umode_t mode)
5bf3258f CH	450	{
	451	struct posix_acl *acl;
	452	int ret = 0;
	453
	454	if (!IS_POSIXACL(inode))
	455	return 0;
	456	if (!inode->i_op->set_acl)
	457	return -EOPNOTSUPP;
	458
	459	acl = get_acl(inode, ACL_TYPE_ACCESS);
	460	if (IS_ERR_OR_NULL(acl))
	461	return PTR_ERR(acl);
	462
37bc1539	463	ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
5bf3258f CH	464	if (ret)
	465	return ret;
	466	ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS);
	467	posix_acl_release(acl);
	468	return ret;
	469	}
bc26ab5f	470	EXPORT_SYMBOL(posix_acl_chmod);
5c8ebd57	471
37bc1539 CH	472	int
	473	posix_acl_create(struct inode dir, umode_t mode,
	474	struct posix_acl default_acl, struct posix_acl acl)
	475	{
	476	struct posix_acl *p;
	477	int ret;
	478
	479	if (S_ISLNK(*mode) \|\| !IS_POSIXACL(dir))
	480	goto no_acl;
	481
	482	p = get_acl(dir, ACL_TYPE_DEFAULT);
	483	if (IS_ERR(p))
	484	return PTR_ERR(p);
	485
	486	if (!p) {
	487	*mode &= ~current_umask();
	488	goto no_acl;
	489	}
	490
	491	*acl = posix_acl_clone(p, GFP_NOFS);
	492	if (!*acl)
	493	return -ENOMEM;
	494
	495	ret = posix_acl_create_masq(*acl, mode);
	496	if (ret < 0) {
	497	posix_acl_release(*acl);
	498	return -ENOMEM;
	499	}
	500
	501	if (ret == 0) {
	502	posix_acl_release(*acl);
	503	*acl = NULL;
	504	}
	505
	506	if (!S_ISDIR(*mode)) {
	507	posix_acl_release(p);
	508	*default_acl = NULL;
	509	} else {
	510	*default_acl = p;
	511	}
	512	return 0;
	513
	514	no_acl:
	515	*default_acl = NULL;
	516	*acl = NULL;
	517	return 0;
	518	}
	519	EXPORT_SYMBOL_GPL(posix_acl_create);
	520
5c8ebd57 CH	521	/*
	522	* Fix up the uids and gids in posix acl extended attributes in place.
	523	*/
	524	static void posix_acl_fix_xattr_userns(
	525	struct user_namespace to, struct user_namespace from,
	526	void *value, size_t size)
	527	{
	528	posix_acl_xattr_header header = (posix_acl_xattr_header )value;
	529	posix_acl_xattr_entry entry = (posix_acl_xattr_entry )(header+1), *end;
	530	int count;
	531	kuid_t uid;
	532	kgid_t gid;
	533
	534	if (!value)
	535	return;
	536	if (size < sizeof(posix_acl_xattr_header))
	537	return;
	538	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
	539	return;
	540
	541	count = posix_acl_xattr_count(size);
	542	if (count < 0)
	543	return;
	544	if (count == 0)
	545	return;
	546
	547	for (end = entry + count; entry != end; entry++) {
	548	switch(le16_to_cpu(entry->e_tag)) {
	549	case ACL_USER:
	550	uid = make_kuid(from, le32_to_cpu(entry->e_id));
	551	entry->e_id = cpu_to_le32(from_kuid(to, uid));
	552	break;
	553	case ACL_GROUP:
	554	gid = make_kgid(from, le32_to_cpu(entry->e_id));
	555	entry->e_id = cpu_to_le32(from_kgid(to, gid));
	556	break;
	557	default:
	558	break;
	559	}
	560	}
	561	}
	562
	563	void posix_acl_fix_xattr_from_user(void *value, size_t size)
	564	{
	565	struct user_namespace *user_ns = current_user_ns();
	566	if (user_ns == &init_user_ns)
	567	return;
	568	posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
	569	}
	570
	571	void posix_acl_fix_xattr_to_user(void *value, size_t size)
	572	{
	573	struct user_namespace *user_ns = current_user_ns();
	574	if (user_ns == &init_user_ns)
	575	return;
	576	posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
	577	}
	578
	579	/*
	580	* Convert from extended attribute to in-memory representation.
	581	*/
	582	struct posix_acl *
	583	posix_acl_from_xattr(struct user_namespace *user_ns,
	584	const void *value, size_t size)
585	{
586	posix_acl_xattr_header header = (posix_acl_xattr_header )value;
587	posix_acl_xattr_entry entry = (posix_acl_xattr_entry )(header+1), *end;
588	int count;
589	struct posix_acl *acl;
590	struct posix_acl_entry *acl_e;
591
592	if (!value)
593	return NULL;
594	if (size < sizeof(posix_acl_xattr_header))
595	return ERR_PTR(-EINVAL);
596	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
597	return ERR_PTR(-EOPNOTSUPP);
598
599	count = posix_acl_xattr_count(size);
600	if (count < 0)
601	return ERR_PTR(-EINVAL);
602	if (count == 0)
603	return NULL;
604
605	acl = posix_acl_alloc(count, GFP_NOFS);
606	if (!acl)
607	return ERR_PTR(-ENOMEM);
608	acl_e = acl->a_entries;
609
610	for (end = entry + count; entry != end; acl_e++, entry++) {
611	acl_e->e_tag = le16_to_cpu(entry->e_tag);
612	acl_e->e_perm = le16_to_cpu(entry->e_perm);
613
614	switch(acl_e->e_tag) {
615	case ACL_USER_OBJ:
616	case ACL_GROUP_OBJ:
617	case ACL_MASK:
618	case ACL_OTHER:
619	break;
620
621	case ACL_USER:
622	acl_e->e_uid =
623	make_kuid(user_ns,
624	le32_to_cpu(entry->e_id));
625	if (!uid_valid(acl_e->e_uid))
626	goto fail;
627	break;
628	case ACL_GROUP:
629	acl_e->e_gid =
630	make_kgid(user_ns,
631	le32_to_cpu(entry->e_id));
632	if (!gid_valid(acl_e->e_gid))
633	goto fail;
634	break;
635
636	default:
637	goto fail;
638	}
639	}
640	return acl;
641
642	fail:
643	posix_acl_release(acl);
644	return ERR_PTR(-EINVAL);
645	}
646	EXPORT_SYMBOL (posix_acl_from_xattr);
647
648	/*
649	* Convert from in-memory to extended attribute representation.
650	*/
651	int
652	posix_acl_to_xattr(struct user_namespace user_ns, const struct posix_acl acl,
653	void *buffer, size_t size)
654	{
655	posix_acl_xattr_header ext_acl = (posix_acl_xattr_header )buffer;
656	posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
657	int real_size, n;
658
659	real_size = posix_acl_xattr_size(acl->a_count);
660	if (!buffer)
661	return real_size;
662	if (real_size > size)
663	return -ERANGE;
664
665	ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
666
667	for (n=0; n < acl->a_count; n++, ext_entry++) {
668	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
669	ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
670	ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
671	switch(acl_e->e_tag) {
672	case ACL_USER:
673	ext_entry->e_id =
674	cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
675	break;
676	case ACL_GROUP:
677	ext_entry->e_id =
678	cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
679	break;
680	default:
681	ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
682	break;
683	}
684	}
685	return real_size;
686	}
687	EXPORT_SYMBOL (posix_acl_to_xattr);
2aeccbe9 CH	688
	689	static int
	690	posix_acl_xattr_get(struct dentry dentry, const char name,
	691	void *value, size_t size, int type)
	692	{
	693	struct posix_acl *acl;
	694	int error;
	695
	696	if (!IS_POSIXACL(dentry->d_inode))
	697	return -EOPNOTSUPP;
	698	if (S_ISLNK(dentry->d_inode->i_mode))
	699	return -EOPNOTSUPP;
	700
	701	acl = get_acl(dentry->d_inode, type);
	702	if (IS_ERR(acl))
	703	return PTR_ERR(acl);
	704	if (acl == NULL)
	705	return -ENODATA;
	706
	707	error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
	708	posix_acl_release(acl);
	709
	710	return error;
	711	}
	712
	713	static int
	714	posix_acl_xattr_set(struct dentry dentry, const char name,
	715	const void *value, size_t size, int flags, int type)
	716	{
	717	struct inode *inode = dentry->d_inode;
	718	struct posix_acl *acl = NULL;
	719	int ret;
	720
	721	if (!IS_POSIXACL(inode))
	722	return -EOPNOTSUPP;
	723	if (!inode->i_op->set_acl)
	724	return -EOPNOTSUPP;
	725
	726	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
	727	return value ? -EACCES : 0;
	728	if (!inode_owner_or_capable(inode))
	729	return -EPERM;
	730
	731	if (value) {
	732	acl = posix_acl_from_xattr(&init_user_ns, value, size);
	733	if (IS_ERR(acl))
	734	return PTR_ERR(acl);
	735
	736	if (acl) {
	737	ret = posix_acl_valid(acl);
	738	if (ret)
	739	goto out;
	740	}
	741	}
	742
	743	ret = inode->i_op->set_acl(inode, acl, type);
	744	out:
	745	posix_acl_release(acl);
	746	return ret;
	747	}
	748
	749	static size_t
	750	posix_acl_xattr_list(struct dentry dentry, char list, size_t list_size,
	751	const char *name, size_t name_len, int type)
752	{
753	const char *xname;
754	size_t size;
755
756	if (!IS_POSIXACL(dentry->d_inode))
757	return -EOPNOTSUPP;
758	if (S_ISLNK(dentry->d_inode->i_mode))
759	return -EOPNOTSUPP;
760
761	if (type == ACL_TYPE_ACCESS)
762	xname = POSIX_ACL_XATTR_ACCESS;
763	else
764	xname = POSIX_ACL_XATTR_DEFAULT;
765
766	size = strlen(xname) + 1;
767	if (list && size <= list_size)
768	memcpy(list, xname, size);
769	return size;
770	}
771
772	const struct xattr_handler posix_acl_access_xattr_handler = {
773	.prefix = POSIX_ACL_XATTR_ACCESS,
774	.flags = ACL_TYPE_ACCESS,
775	.list = posix_acl_xattr_list,
776	.get = posix_acl_xattr_get,
777	.set = posix_acl_xattr_set,
778	};
779	EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
780
781	const struct xattr_handler posix_acl_default_xattr_handler = {
782	.prefix = POSIX_ACL_XATTR_DEFAULT,
783	.flags = ACL_TYPE_DEFAULT,
784	.list = posix_acl_xattr_list,
785	.get = posix_acl_xattr_get,
786	.set = posix_acl_xattr_set,
787	};
788	EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);
feda821e CH	789
	790	int simple_set_acl(struct inode inode, struct posix_acl acl, int type)
	791	{
	792	int error;
	793
	794	if (type == ACL_TYPE_ACCESS) {
	795	error = posix_acl_equiv_mode(acl, &inode->i_mode);
	796	if (error < 0)
	797	return 0;
	798	if (error == 0)
	799	acl = NULL;
	800	}
	801
	802	inode->i_ctime = CURRENT_TIME;
	803	set_cached_acl(inode, type, acl);
	804	return 0;
	805	}
	806
	807	int simple_acl_create(struct inode dir, struct inode inode)
	808	{
	809	struct posix_acl default_acl, acl;
	810	int error;
	811
	812	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	813	if (error)
	814	return error;
	815
	816	set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
	817	set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
	818
	819	if (default_acl)
	820	posix_acl_release(default_acl);
	821	if (acl)
	822	posix_acl_release(acl);
	823	return 0;
	824	}