[linux.git] / fs / ext4 / acl.c

/*
 * linux/fs/ext4/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
 */

#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/ext4_jbd2.h>
#include <linux/ext4_fs.h>
#include "xattr.h"
#include "acl.h"

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *
ext4_acl_from_disk(const void *value, size_t size)
{
	const char *end = (char *)value + size;
	int n, count;
	struct posix_acl *acl;

	if (!value)
		return NULL;
	if (size < sizeof(ext4_acl_header))
		 return ERR_PTR(-EINVAL);
	if (((ext4_acl_header *)value)->a_version !=
	    cpu_to_le32(EXT4_ACL_VERSION))
		return ERR_PTR(-EINVAL);
	value = (char *)value + sizeof(ext4_acl_header);
	count = ext4_acl_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);
	if (count == 0)
		return NULL;
	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);
	for (n=0; n < count; n++) {
		ext4_acl_entry *entry =
			(ext4_acl_entry *)value;
		if ((char *)value + sizeof(ext4_acl_entry_short) > end)
			goto fail;
		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
		switch(acl->a_entries[n].e_tag) {
			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				value = (char *)value +
					sizeof(ext4_acl_entry_short);
				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
				break;

			case ACL_USER:
			case ACL_GROUP:
				value = (char *)value + sizeof(ext4_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_id =
					le32_to_cpu(entry->e_id);
				break;

			default:
				goto fail;
		}
	}
	if (value != end)
		goto fail;
	return acl;

fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
}

/*
 * Convert from in-memory to filesystem representation.
 */
static void *
ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
	ext4_acl_header *ext_acl;
	char *e;
	size_t n;

	*size = ext4_acl_size(acl->a_count);
	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
			sizeof(ext4_acl_entry), GFP_KERNEL);
	if (!ext_acl)
		return ERR_PTR(-ENOMEM);
	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
	e = (char *)ext_acl + sizeof(ext4_acl_header);
	for (n=0; n < acl->a_count; n++) {
		ext4_acl_entry *entry = (ext4_acl_entry *)e;
		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
		switch(acl->a_entries[n].e_tag) {
			case ACL_USER:
			case ACL_GROUP:
				entry->e_id =
					cpu_to_le32(acl->a_entries[n].e_id);
				e += sizeof(ext4_acl_entry);
				break;

			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				e += sizeof(ext4_acl_entry_short);
				break;

			default:
				goto fail;
		}
	}
	return (char *)ext_acl;

fail:
	kfree(ext_acl);
	return ERR_PTR(-EINVAL);
}

static inline struct posix_acl *
ext4_iget_acl(struct inode *inode, struct posix_acl **i_acl)
{
	struct posix_acl *acl = EXT4_ACL_NOT_CACHED;

	spin_lock(&inode->i_lock);
	if (*i_acl != EXT4_ACL_NOT_CACHED)
		acl = posix_acl_dup(*i_acl);
	spin_unlock(&inode->i_lock);

	return acl;
}

static inline void
ext4_iset_acl(struct inode *inode, struct posix_acl **i_acl,
                  struct posix_acl *acl)
{
	spin_lock(&inode->i_lock);
	if (*i_acl != EXT4_ACL_NOT_CACHED)
		posix_acl_release(*i_acl);
	*i_acl = posix_acl_dup(acl);
	spin_unlock(&inode->i_lock);
}

/*
 * Inode operation get_posix_acl().
 *
 * inode->i_mutex: don't care
 */
static struct posix_acl *
ext4_get_acl(struct inode *inode, int type)
{
	struct ext4_inode_info *ei = EXT4_I(inode);
	int name_index;
	char *value = NULL;
	struct posix_acl *acl;
	int retval;

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return NULL;

	switch(type) {
		case ACL_TYPE_ACCESS:
			acl = ext4_iget_acl(inode, &ei->i_acl);
			if (acl != EXT4_ACL_NOT_CACHED)
				return acl;
			name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
			break;

		case ACL_TYPE_DEFAULT:
			acl = ext4_iget_acl(inode, &ei->i_default_acl);
			if (acl != EXT4_ACL_NOT_CACHED)
				return acl;
			name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
			break;

		default:
			return ERR_PTR(-EINVAL);
	}
	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_KERNEL);
		if (!value)
			return ERR_PTR(-ENOMEM);
		retval = ext4_xattr_get(inode, name_index, "", value, retval);
	}
	if (retval > 0)
		acl = ext4_acl_from_disk(value, retval);
	else if (retval == -ENODATA || retval == -ENOSYS)
		acl = NULL;
	else
		acl = ERR_PTR(retval);
	kfree(value);

	if (!IS_ERR(acl)) {
		switch(type) {
			case ACL_TYPE_ACCESS:
				ext4_iset_acl(inode, &ei->i_acl, acl);
				break;

			case ACL_TYPE_DEFAULT:
				ext4_iset_acl(inode, &ei->i_default_acl, acl);
				break;
		}
	}
	return acl;
}

/*
 * Set the access or default ACL of an inode.
 *
 * inode->i_mutex: down unless called from ext4_new_inode
 */
static int
ext4_set_acl(handle_t *handle, struct inode *inode, int type,
	     struct posix_acl *acl)
{
	struct ext4_inode_info *ei = EXT4_I(inode);
	int name_index;
	void *value = NULL;
	size_t size = 0;
	int error;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;

	switch(type) {
		case ACL_TYPE_ACCESS:
			name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
			if (acl) {
				mode_t mode = inode->i_mode;
				error = posix_acl_equiv_mode(acl, &mode);
				if (error < 0)
					return error;
				else {
					inode->i_mode = mode;
					ext4_mark_inode_dirty(handle, inode);
					if (error == 0)
						acl = NULL;
				}
			}
			break;

		case ACL_TYPE_DEFAULT:
			name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
			if (!S_ISDIR(inode->i_mode))
				return acl ? -EACCES : 0;
			break;

		default:
			return -EINVAL;
	}
	if (acl) {
		value = ext4_acl_to_disk(acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext4_xattr_set_handle(handle, inode, name_index, "",
				      value, size, 0);

	kfree(value);
	if (!error) {
		switch(type) {
			case ACL_TYPE_ACCESS:
				ext4_iset_acl(inode, &ei->i_acl, acl);
				break;

			case ACL_TYPE_DEFAULT:
				ext4_iset_acl(inode, &ei->i_default_acl, acl);
				break;
		}
	}
	return error;
}

static int
ext4_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);

	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl) {
		int error = posix_acl_permission(inode, acl, mask);
		posix_acl_release(acl);
		return error;
	}

	return -EAGAIN;
}

int
ext4_permission(struct inode *inode, int mask, struct nameidata *nd)
{
	return generic_permission(inode, mask, ext4_check_acl);
}

/*
 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
 *
 * dir->i_mutex: down
 * inode->i_mutex: up (access to inode is still exclusive)
 */
int
ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
{
	struct posix_acl *acl = NULL;
	int error = 0;

	if (!S_ISLNK(inode->i_mode)) {
		if (test_opt(dir->i_sb, POSIX_ACL)) {
			acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
			if (IS_ERR(acl))
				return PTR_ERR(acl);
		}
		if (!acl)
			inode->i_mode &= ~current->fs->umask;
	}
	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
		struct posix_acl *clone;
		mode_t mode;

		if (S_ISDIR(inode->i_mode)) {
			error = ext4_set_acl(handle, inode,
					     ACL_TYPE_DEFAULT, acl);
			if (error)
				goto cleanup;
		}
		clone = posix_acl_clone(acl, GFP_KERNEL);
		error = -ENOMEM;
		if (!clone)
			goto cleanup;

		mode = inode->i_mode;
		error = posix_acl_create_masq(clone, &mode);
		if (error >= 0) {
			inode->i_mode = mode;
			if (error > 0) {
				/* This is an extended ACL */
				error = ext4_set_acl(handle, inode,
						     ACL_TYPE_ACCESS, clone);
			}
		}
		posix_acl_release(clone);
	}
cleanup:
	posix_acl_release(acl);
	return error;
}

/*
 * Does chmod for an inode that may have an Access Control List. The
 * inode->i_mode field must be updated to the desired value by the caller
 * before calling this function.
 * Returns 0 on success, or a negative error number.
 *
 * We change the ACL rather than storing some ACL entries in the file
 * mode permission bits (which would be more efficient), because that
 * would break once additional permissions (like  ACL_APPEND, ACL_DELETE
 * for directories) are added. There are no more bits available in the
 * file mode.
 *
 * inode->i_mutex: down
 */
int
ext4_acl_chmod(struct inode *inode)
{
	struct posix_acl *acl, *clone;
        int error;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;
	acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
	if (IS_ERR(acl) || !acl)
		return PTR_ERR(acl);
	clone = posix_acl_clone(acl, GFP_KERNEL);
	posix_acl_release(acl);
	if (!clone)
		return -ENOMEM;
	error = posix_acl_chmod_masq(clone, inode->i_mode);
	if (!error) {
		handle_t *handle;
		int retries = 0;

	retry:
		handle = ext4_journal_start(inode,
				EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			ext4_std_error(inode->i_sb, error);
			goto out;
		}
		error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
		ext4_journal_stop(handle);
		if (error == -ENOSPC &&
		    ext4_should_retry_alloc(inode->i_sb, &retries))
			goto retry;
	}
out:
	posix_acl_release(clone);
	return error;
}

/*
 * Extended attribute handlers
 */
static size_t
ext4_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len,
			   const char *name, size_t name_len)
{
	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;
	if (list && size <= list_len)
		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
	return size;
}

static size_t
ext4_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len,
			    const char *name, size_t name_len)
{
	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;
	if (list && size <= list_len)
		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
	return size;
}

static int
ext4_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
{
	struct posix_acl *acl;
	int error;

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return -EOPNOTSUPP;

	acl = ext4_get_acl(inode, type);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl == NULL)
		return -ENODATA;
	error = posix_acl_to_xattr(acl, buffer, size);
	posix_acl_release(acl);

	return error;
}

static int
ext4_xattr_get_acl_access(struct inode *inode, const char *name,
			  void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext4_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
}

static int
ext4_xattr_get_acl_default(struct inode *inode, const char *name,
			   void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext4_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
}

static int
ext4_xattr_set_acl(struct inode *inode, int type, const void *value,
		   size_t size)
{
	handle_t *handle;
	struct posix_acl *acl;
	int error, retries = 0;

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return -EOPNOTSUPP;
	if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
		return -EPERM;

	if (value) {
		acl = posix_acl_from_xattr(value, size);
		if (IS_ERR(acl))
			return PTR_ERR(acl);
		else if (acl) {
			error = posix_acl_valid(acl);
			if (error)
				goto release_and_out;
		}
	} else
		acl = NULL;

retry:
	handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
	if (IS_ERR(handle))
		return PTR_ERR(handle);
	error = ext4_set_acl(handle, inode, type, acl);
	ext4_journal_stop(handle);
	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
		goto retry;

release_and_out:
	posix_acl_release(acl);
	return error;
}

static int
ext4_xattr_set_acl_access(struct inode *inode, const char *name,
			  const void *value, size_t size, int flags)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext4_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
}

static int
ext4_xattr_set_acl_default(struct inode *inode, const char *name,
			   const void *value, size_t size, int flags)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext4_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
}

struct xattr_handler ext4_xattr_acl_access_handler = {
	.prefix	= POSIX_ACL_XATTR_ACCESS,
	.list	= ext4_xattr_list_acl_access,
	.get	= ext4_xattr_get_acl_access,
	.set	= ext4_xattr_set_acl_access,
};

struct xattr_handler ext4_xattr_acl_default_handler = {
	.prefix	= POSIX_ACL_XATTR_DEFAULT,
	.list	= ext4_xattr_list_acl_default,
	.get	= ext4_xattr_get_acl_default,
	.set	= ext4_xattr_set_acl_default,
};
Commit	Line	Data
ac27a0ec	1	/*
617ba13b	2	* linux/fs/ext4/acl.c
ac27a0ec DK	3	*
	4	* Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
	5	*/
	6
	7	#include <linux/init.h>
	8	#include <linux/sched.h>
	9	#include <linux/slab.h>
	10	#include <linux/capability.h>
	11	#include <linux/fs.h>
dab291af	12	#include <linux/ext4_jbd2.h>
617ba13b	13	#include <linux/ext4_fs.h>
ac27a0ec DK	14	#include "xattr.h"
	15	#include "acl.h"
	16
	17	/*
	18	* Convert from filesystem to in-memory representation.
	19	*/
	20	static struct posix_acl *
617ba13b	21	ext4_acl_from_disk(const void *value, size_t size)
ac27a0ec DK	22	{
	23	const char end = (char )value + size;
	24	int n, count;
	25	struct posix_acl *acl;
	26
	27	if (!value)
	28	return NULL;
617ba13b	29	if (size < sizeof(ext4_acl_header))
ac27a0ec	30	return ERR_PTR(-EINVAL);
617ba13b MC	31	if (((ext4_acl_header *)value)->a_version !=
617ba13b MC	32	cpu_to_le32(EXT4_ACL_VERSION))
ac27a0ec	33	return ERR_PTR(-EINVAL);
617ba13b MC	34	value = (char *)value + sizeof(ext4_acl_header);
617ba13b MC	35	count = ext4_acl_count(size);
ac27a0ec DK	36	if (count < 0)
	37	return ERR_PTR(-EINVAL);
	38	if (count == 0)
	39	return NULL;
	40	acl = posix_acl_alloc(count, GFP_KERNEL);
	41	if (!acl)
	42	return ERR_PTR(-ENOMEM);
	43	for (n=0; n < count; n++) {
617ba13b MC	44	ext4_acl_entry *entry =
	45	(ext4_acl_entry *)value;
	46	if ((char *)value + sizeof(ext4_acl_entry_short) > end)
ac27a0ec DK	47	goto fail;
	48	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	49	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
	50	switch(acl->a_entries[n].e_tag) {
	51	case ACL_USER_OBJ:
	52	case ACL_GROUP_OBJ:
	53	case ACL_MASK:
	54	case ACL_OTHER:
	55	value = (char *)value +
617ba13b	56	sizeof(ext4_acl_entry_short);
ac27a0ec DK	57	acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
	58	break;
	59
	60	case ACL_USER:
	61	case ACL_GROUP:
617ba13b	62	value = (char *)value + sizeof(ext4_acl_entry);
ac27a0ec DK	63	if ((char *)value > end)
	64	goto fail;
	65	acl->a_entries[n].e_id =
	66	le32_to_cpu(entry->e_id);
	67	break;
	68
	69	default:
	70	goto fail;
	71	}
	72	}
	73	if (value != end)
	74	goto fail;
	75	return acl;
	76
	77	fail:
	78	posix_acl_release(acl);
	79	return ERR_PTR(-EINVAL);
	80	}
	81
	82	/*
	83	* Convert from in-memory to filesystem representation.
	84	*/
	85	static void *
617ba13b	86	ext4_acl_to_disk(const struct posix_acl acl, size_t size)
ac27a0ec	87	{
617ba13b	88	ext4_acl_header *ext_acl;
ac27a0ec DK	89	char *e;
	90	size_t n;
	91
617ba13b MC	92	*size = ext4_acl_size(acl->a_count);
	93	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
	94	sizeof(ext4_acl_entry), GFP_KERNEL);
ac27a0ec DK	95	if (!ext_acl)
ac27a0ec DK	96	return ERR_PTR(-ENOMEM);
617ba13b MC	97	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
617ba13b MC	98	e = (char *)ext_acl + sizeof(ext4_acl_header);
ac27a0ec	99	for (n=0; n < acl->a_count; n++) {
617ba13b	100	ext4_acl_entry entry = (ext4_acl_entry )e;
ac27a0ec DK	101	entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
	102	entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
	103	switch(acl->a_entries[n].e_tag) {
	104	case ACL_USER:
	105	case ACL_GROUP:
	106	entry->e_id =
	107	cpu_to_le32(acl->a_entries[n].e_id);
617ba13b	108	e += sizeof(ext4_acl_entry);
ac27a0ec DK	109	break;
	110
	111	case ACL_USER_OBJ:
	112	case ACL_GROUP_OBJ:
	113	case ACL_MASK:
	114	case ACL_OTHER:
617ba13b	115	e += sizeof(ext4_acl_entry_short);
ac27a0ec DK	116	break;
	117
	118	default:
	119	goto fail;
	120	}
	121	}
	122	return (char *)ext_acl;
	123
	124	fail:
	125	kfree(ext_acl);
	126	return ERR_PTR(-EINVAL);
	127	}
	128
	129	static inline struct posix_acl *
617ba13b	130	ext4_iget_acl(struct inode inode, struct posix_acl *i_acl)
ac27a0ec	131	{
617ba13b	132	struct posix_acl *acl = EXT4_ACL_NOT_CACHED;
ac27a0ec DK	133
ac27a0ec DK	134	spin_lock(&inode->i_lock);
617ba13b	135	if (*i_acl != EXT4_ACL_NOT_CACHED)
ac27a0ec DK	136	acl = posix_acl_dup(*i_acl);
	137	spin_unlock(&inode->i_lock);
	138
	139	return acl;
	140	}
	141
	142	static inline void
617ba13b	143	ext4_iset_acl(struct inode inode, struct posix_acl *i_acl,
ac27a0ec DK	144	struct posix_acl *acl)
	145	{
	146	spin_lock(&inode->i_lock);
617ba13b	147	if (*i_acl != EXT4_ACL_NOT_CACHED)
ac27a0ec DK	148	posix_acl_release(*i_acl);
	149	*i_acl = posix_acl_dup(acl);
	150	spin_unlock(&inode->i_lock);
	151	}
	152
	153	/*
	154	* Inode operation get_posix_acl().
	155	*
	156	* inode->i_mutex: don't care
	157	*/
	158	static struct posix_acl *
617ba13b	159	ext4_get_acl(struct inode *inode, int type)
ac27a0ec	160	{
617ba13b	161	struct ext4_inode_info *ei = EXT4_I(inode);
ac27a0ec DK	162	int name_index;
	163	char *value = NULL;
	164	struct posix_acl *acl;
	165	int retval;
	166
	167	if (!test_opt(inode->i_sb, POSIX_ACL))
	168	return NULL;
	169
	170	switch(type) {
	171	case ACL_TYPE_ACCESS:
617ba13b MC	172	acl = ext4_iget_acl(inode, &ei->i_acl);
617ba13b MC	173	if (acl != EXT4_ACL_NOT_CACHED)
ac27a0ec	174	return acl;
617ba13b	175	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
ac27a0ec DK	176	break;
	177
	178	case ACL_TYPE_DEFAULT:
617ba13b MC	179	acl = ext4_iget_acl(inode, &ei->i_default_acl);
617ba13b MC	180	if (acl != EXT4_ACL_NOT_CACHED)
ac27a0ec	181	return acl;
617ba13b	182	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
ac27a0ec DK	183	break;
	184
	185	default:
	186	return ERR_PTR(-EINVAL);
	187	}
617ba13b	188	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
ac27a0ec DK	189	if (retval > 0) {
	190	value = kmalloc(retval, GFP_KERNEL);
	191	if (!value)
	192	return ERR_PTR(-ENOMEM);
617ba13b	193	retval = ext4_xattr_get(inode, name_index, "", value, retval);
ac27a0ec DK	194	}
ac27a0ec DK	195	if (retval > 0)
617ba13b	196	acl = ext4_acl_from_disk(value, retval);
ac27a0ec DK	197	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	198	acl = NULL;
	199	else
	200	acl = ERR_PTR(retval);
	201	kfree(value);
	202
	203	if (!IS_ERR(acl)) {
	204	switch(type) {
	205	case ACL_TYPE_ACCESS:
617ba13b	206	ext4_iset_acl(inode, &ei->i_acl, acl);
ac27a0ec DK	207	break;
	208
	209	case ACL_TYPE_DEFAULT:
617ba13b	210	ext4_iset_acl(inode, &ei->i_default_acl, acl);
ac27a0ec DK	211	break;
	212	}
	213	}
	214	return acl;
	215	}
	216
	217	/*
	218	* Set the access or default ACL of an inode.
	219	*
617ba13b	220	* inode->i_mutex: down unless called from ext4_new_inode
ac27a0ec DK	221	*/
ac27a0ec DK	222	static int
617ba13b	223	ext4_set_acl(handle_t handle, struct inode inode, int type,
ac27a0ec DK	224	struct posix_acl *acl)
ac27a0ec DK	225	{
617ba13b	226	struct ext4_inode_info *ei = EXT4_I(inode);
ac27a0ec DK	227	int name_index;
	228	void *value = NULL;
	229	size_t size = 0;
	230	int error;
	231
	232	if (S_ISLNK(inode->i_mode))
	233	return -EOPNOTSUPP;
	234
	235	switch(type) {
	236	case ACL_TYPE_ACCESS:
617ba13b	237	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
ac27a0ec DK	238	if (acl) {
	239	mode_t mode = inode->i_mode;
	240	error = posix_acl_equiv_mode(acl, &mode);
	241	if (error < 0)
	242	return error;
	243	else {
	244	inode->i_mode = mode;
617ba13b	245	ext4_mark_inode_dirty(handle, inode);
ac27a0ec DK	246	if (error == 0)
	247	acl = NULL;
	248	}
	249	}
	250	break;
	251
	252	case ACL_TYPE_DEFAULT:
617ba13b	253	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
ac27a0ec DK	254	if (!S_ISDIR(inode->i_mode))
	255	return acl ? -EACCES : 0;
	256	break;
	257
	258	default:
	259	return -EINVAL;
	260	}
	261	if (acl) {
617ba13b	262	value = ext4_acl_to_disk(acl, &size);
ac27a0ec DK	263	if (IS_ERR(value))
	264	return (int)PTR_ERR(value);
	265	}
	266
617ba13b	267	error = ext4_xattr_set_handle(handle, inode, name_index, "",
ac27a0ec DK	268	value, size, 0);
	269
	270	kfree(value);
	271	if (!error) {
	272	switch(type) {
	273	case ACL_TYPE_ACCESS:
617ba13b	274	ext4_iset_acl(inode, &ei->i_acl, acl);
ac27a0ec DK	275	break;
	276
	277	case ACL_TYPE_DEFAULT:
617ba13b	278	ext4_iset_acl(inode, &ei->i_default_acl, acl);
ac27a0ec DK	279	break;
	280	}
	281	}
	282	return error;
	283	}
	284
	285	static int
617ba13b	286	ext4_check_acl(struct inode *inode, int mask)
ac27a0ec	287	{
617ba13b	288	struct posix_acl *acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec DK	289
	290	if (IS_ERR(acl))
	291	return PTR_ERR(acl);
	292	if (acl) {
	293	int error = posix_acl_permission(inode, acl, mask);
	294	posix_acl_release(acl);
	295	return error;
	296	}
	297
	298	return -EAGAIN;
	299	}
	300
	301	int
617ba13b	302	ext4_permission(struct inode inode, int mask, struct nameidata nd)
ac27a0ec	303	{
617ba13b	304	return generic_permission(inode, mask, ext4_check_acl);
ac27a0ec DK	305	}
	306
	307	/*
617ba13b	308	* Initialize the ACLs of a new inode. Called from ext4_new_inode.
ac27a0ec DK	309	*
	310	* dir->i_mutex: down
	311	* inode->i_mutex: up (access to inode is still exclusive)
	312	*/
	313	int
617ba13b	314	ext4_init_acl(handle_t handle, struct inode inode, struct inode *dir)
ac27a0ec DK	315	{
	316	struct posix_acl *acl = NULL;
	317	int error = 0;
	318
	319	if (!S_ISLNK(inode->i_mode)) {
	320	if (test_opt(dir->i_sb, POSIX_ACL)) {
617ba13b	321	acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
ac27a0ec DK	322	if (IS_ERR(acl))
	323	return PTR_ERR(acl);
	324	}
	325	if (!acl)
	326	inode->i_mode &= ~current->fs->umask;
	327	}
	328	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
	329	struct posix_acl *clone;
	330	mode_t mode;
	331
	332	if (S_ISDIR(inode->i_mode)) {
617ba13b	333	error = ext4_set_acl(handle, inode,
ac27a0ec DK	334	ACL_TYPE_DEFAULT, acl);
	335	if (error)
	336	goto cleanup;
	337	}
	338	clone = posix_acl_clone(acl, GFP_KERNEL);
	339	error = -ENOMEM;
	340	if (!clone)
	341	goto cleanup;
	342
	343	mode = inode->i_mode;
	344	error = posix_acl_create_masq(clone, &mode);
	345	if (error >= 0) {
	346	inode->i_mode = mode;
	347	if (error > 0) {
	348	/* This is an extended ACL */
617ba13b	349	error = ext4_set_acl(handle, inode,
ac27a0ec DK	350	ACL_TYPE_ACCESS, clone);
	351	}
	352	}
	353	posix_acl_release(clone);
	354	}
	355	cleanup:
	356	posix_acl_release(acl);
	357	return error;
	358	}
	359
	360	/*
	361	* Does chmod for an inode that may have an Access Control List. The
	362	* inode->i_mode field must be updated to the desired value by the caller
	363	* before calling this function.
	364	* Returns 0 on success, or a negative error number.
	365	*
	366	* We change the ACL rather than storing some ACL entries in the file
	367	* mode permission bits (which would be more efficient), because that
	368	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
	369	* for directories) are added. There are no more bits available in the
	370	* file mode.
	371	*
	372	* inode->i_mutex: down
	373	*/
	374	int
617ba13b	375	ext4_acl_chmod(struct inode *inode)
ac27a0ec DK	376	{
	377	struct posix_acl acl, clone;
	378	int error;
	379
	380	if (S_ISLNK(inode->i_mode))
	381	return -EOPNOTSUPP;
	382	if (!test_opt(inode->i_sb, POSIX_ACL))
	383	return 0;
617ba13b	384	acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
ac27a0ec DK	385	if (IS_ERR(acl) \|\| !acl)
	386	return PTR_ERR(acl);
	387	clone = posix_acl_clone(acl, GFP_KERNEL);
	388	posix_acl_release(acl);
	389	if (!clone)
	390	return -ENOMEM;
	391	error = posix_acl_chmod_masq(clone, inode->i_mode);
	392	if (!error) {
	393	handle_t *handle;
	394	int retries = 0;
	395
	396	retry:
617ba13b MC	397	handle = ext4_journal_start(inode,
617ba13b MC	398	EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec DK	399	if (IS_ERR(handle)) {
ac27a0ec DK	400	error = PTR_ERR(handle);
617ba13b	401	ext4_std_error(inode->i_sb, error);
ac27a0ec DK	402	goto out;
ac27a0ec DK	403	}
617ba13b MC	404	error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
617ba13b MC	405	ext4_journal_stop(handle);
ac27a0ec	406	if (error == -ENOSPC &&
617ba13b	407	ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec DK	408	goto retry;
	409	}
	410	out:
	411	posix_acl_release(clone);
	412	return error;
	413	}
	414
	415	/*
	416	* Extended attribute handlers
	417	*/
	418	static size_t
617ba13b	419	ext4_xattr_list_acl_access(struct inode inode, char list, size_t list_len,
ac27a0ec DK	420	const char *name, size_t name_len)
	421	{
	422	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
	423
	424	if (!test_opt(inode->i_sb, POSIX_ACL))
	425	return 0;
	426	if (list && size <= list_len)
	427	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
	428	return size;
	429	}
	430
	431	static size_t
617ba13b	432	ext4_xattr_list_acl_default(struct inode inode, char list, size_t list_len,
ac27a0ec DK	433	const char *name, size_t name_len)
	434	{
	435	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
	436
	437	if (!test_opt(inode->i_sb, POSIX_ACL))
	438	return 0;
	439	if (list && size <= list_len)
	440	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
	441	return size;
	442	}
	443
	444	static int
617ba13b	445	ext4_xattr_get_acl(struct inode inode, int type, void buffer, size_t size)
ac27a0ec DK	446	{
	447	struct posix_acl *acl;
	448	int error;
	449
	450	if (!test_opt(inode->i_sb, POSIX_ACL))
	451	return -EOPNOTSUPP;
	452
617ba13b	453	acl = ext4_get_acl(inode, type);
ac27a0ec DK	454	if (IS_ERR(acl))
	455	return PTR_ERR(acl);
	456	if (acl == NULL)
	457	return -ENODATA;
	458	error = posix_acl_to_xattr(acl, buffer, size);
	459	posix_acl_release(acl);
	460
	461	return error;
	462	}
	463
	464	static int
617ba13b	465	ext4_xattr_get_acl_access(struct inode inode, const char name,
ac27a0ec DK	466	void *buffer, size_t size)
	467	{
	468	if (strcmp(name, "") != 0)
	469	return -EINVAL;
617ba13b	470	return ext4_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
ac27a0ec DK	471	}
	472
	473	static int
617ba13b	474	ext4_xattr_get_acl_default(struct inode inode, const char name,
ac27a0ec DK	475	void *buffer, size_t size)
	476	{
	477	if (strcmp(name, "") != 0)
	478	return -EINVAL;
617ba13b	479	return ext4_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
ac27a0ec DK	480	}
	481
	482	static int
617ba13b	483	ext4_xattr_set_acl(struct inode inode, int type, const void value,
ac27a0ec DK	484	size_t size)
	485	{
	486	handle_t *handle;
	487	struct posix_acl *acl;
	488	int error, retries = 0;
	489
	490	if (!test_opt(inode->i_sb, POSIX_ACL))
	491	return -EOPNOTSUPP;
	492	if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
	493	return -EPERM;
	494
	495	if (value) {
	496	acl = posix_acl_from_xattr(value, size);
	497	if (IS_ERR(acl))
	498	return PTR_ERR(acl);
	499	else if (acl) {
	500	error = posix_acl_valid(acl);
	501	if (error)
	502	goto release_and_out;
	503	}
	504	} else
	505	acl = NULL;
	506
	507	retry:
617ba13b	508	handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
ac27a0ec DK	509	if (IS_ERR(handle))
ac27a0ec DK	510	return PTR_ERR(handle);
617ba13b MC	511	error = ext4_set_acl(handle, inode, type, acl);
	512	ext4_journal_stop(handle);
	513	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
ac27a0ec DK	514	goto retry;
	515
	516	release_and_out:
	517	posix_acl_release(acl);
	518	return error;
	519	}
	520
	521	static int
617ba13b	522	ext4_xattr_set_acl_access(struct inode inode, const char name,
ac27a0ec DK	523	const void *value, size_t size, int flags)
	524	{
	525	if (strcmp(name, "") != 0)
	526	return -EINVAL;
617ba13b	527	return ext4_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
ac27a0ec DK	528	}
	529
	530	static int
617ba13b	531	ext4_xattr_set_acl_default(struct inode inode, const char name,
ac27a0ec DK	532	const void *value, size_t size, int flags)
	533	{
	534	if (strcmp(name, "") != 0)
	535	return -EINVAL;
617ba13b	536	return ext4_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
ac27a0ec DK	537	}
ac27a0ec DK	538
617ba13b	539	struct xattr_handler ext4_xattr_acl_access_handler = {
ac27a0ec	540	.prefix = POSIX_ACL_XATTR_ACCESS,
617ba13b MC	541	.list = ext4_xattr_list_acl_access,
	542	.get = ext4_xattr_get_acl_access,
	543	.set = ext4_xattr_set_acl_access,
ac27a0ec DK	544	};
ac27a0ec DK	545
617ba13b	546	struct xattr_handler ext4_xattr_acl_default_handler = {
ac27a0ec	547	.prefix = POSIX_ACL_XATTR_DEFAULT,
617ba13b MC	548	.list = ext4_xattr_list_acl_default,
	549	.get = ext4_xattr_get_acl_default,
	550	.set = ext4_xattr_set_acl_default,
ac27a0ec	551	};