[mirror_ubuntu-zesty-kernel.git] / fs / ext3 / acl.c

/*
 * linux/fs/ext3/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 */

#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/ext3_jbd.h>
#include <linux/ext3_fs.h>
#include "xattr.h"
#include "acl.h"

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *
ext3_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(ext3_acl_header))
		 return ERR_PTR(-EINVAL);
	if (((ext3_acl_header *)value)->a_version !=
	    cpu_to_le32(EXT3_ACL_VERSION))
		return ERR_PTR(-EINVAL);
	value = (char *)value + sizeof(ext3_acl_header);
	count = ext3_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++) {
		ext3_acl_entry *entry =
			(ext3_acl_entry *)value;
		if ((char *)value + sizeof(ext3_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(ext3_acl_entry_short);
				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
				break;

			case ACL_USER:
			case ACL_GROUP:
				value = (char *)value + sizeof(ext3_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 *
ext3_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
	ext3_acl_header *ext_acl;
	char *e;
	size_t n;

	*size = ext3_acl_size(acl->a_count);
	ext_acl = (ext3_acl_header *)kmalloc(sizeof(ext3_acl_header) +
		acl->a_count * sizeof(ext3_acl_entry), GFP_KERNEL);
	if (!ext_acl)
		return ERR_PTR(-ENOMEM);
	ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
	e = (char *)ext_acl + sizeof(ext3_acl_header);
	for (n=0; n < acl->a_count; n++) {
		ext3_acl_entry *entry = (ext3_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(ext3_acl_entry);
				break;

			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				e += sizeof(ext3_acl_entry_short);
				break;

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

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

static inline struct posix_acl *
ext3_iget_acl(struct inode *inode, struct posix_acl **i_acl)
{
	struct posix_acl *acl = EXT3_ACL_NOT_CACHED;

	spin_lock(&inode->i_lock);
	if (*i_acl != EXT3_ACL_NOT_CACHED)
		acl = posix_acl_dup(*i_acl);
	spin_unlock(&inode->i_lock);

	return acl;
}

static inline void
ext3_iset_acl(struct inode *inode, struct posix_acl **i_acl,
                  struct posix_acl *acl)
{
	spin_lock(&inode->i_lock);
	if (*i_acl != EXT3_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 *
ext3_get_acl(struct inode *inode, int type)
{
	struct ext3_inode_info *ei = EXT3_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 = ext3_iget_acl(inode, &ei->i_acl);
			if (acl != EXT3_ACL_NOT_CACHED)
				return acl;
			name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
			break;

		case ACL_TYPE_DEFAULT:
			acl = ext3_iget_acl(inode, &ei->i_default_acl);
			if (acl != EXT3_ACL_NOT_CACHED)
				return acl;
			name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
			break;

		default:
			return ERR_PTR(-EINVAL);
	}
	retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_KERNEL);
		if (!value)
			return ERR_PTR(-ENOMEM);
		retval = ext3_xattr_get(inode, name_index, "", value, retval);
	}
	if (retval > 0)
		acl = ext3_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:
				ext3_iset_acl(inode, &ei->i_acl, acl);
				break;

			case ACL_TYPE_DEFAULT:
				ext3_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 ext3_new_inode
 */
static int
ext3_set_acl(handle_t *handle, struct inode *inode, int type,
	     struct posix_acl *acl)
{
	struct ext3_inode_info *ei = EXT3_I(inode);
	int name_index;
	void *value = NULL;
	size_t size;
	int error;

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

	switch(type) {
		case ACL_TYPE_ACCESS:
			name_index = EXT3_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;
					ext3_mark_inode_dirty(handle, inode);
					if (error == 0)
						acl = NULL;
				}
			}
			break;

		case ACL_TYPE_DEFAULT:
			name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
			if (!S_ISDIR(inode->i_mode))
				return acl ? -EACCES : 0;
			break;

		default:
			return -EINVAL;
	}
 	if (acl) {
		value = ext3_acl_to_disk(acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext3_xattr_set_handle(handle, inode, name_index, "",
				      value, size, 0);

	kfree(value);
	if (!error) {
		switch(type) {
			case ACL_TYPE_ACCESS:
				ext3_iset_acl(inode, &ei->i_acl, acl);
				break;

			case ACL_TYPE_DEFAULT:
				ext3_iset_acl(inode, &ei->i_default_acl, acl);
				break;
		}
	}
	return error;
}

static int
ext3_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl = ext3_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
ext3_permission(struct inode *inode, int mask, struct nameidata *nd)
{
	return generic_permission(inode, mask, ext3_check_acl);
}

/*
 * Initialize the ACLs of a new inode. Called from ext3_new_inode.
 *
 * dir->i_mutex: down
 * inode->i_mutex: up (access to inode is still exclusive)
 */
int
ext3_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 = ext3_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 = ext3_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 = ext3_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
ext3_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 = ext3_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 = ext3_journal_start(inode,
				EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			ext3_std_error(inode->i_sb, error);
			goto out;
		}
		error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
		ext3_journal_stop(handle);
		if (error == -ENOSPC &&
		    ext3_should_retry_alloc(inode->i_sb, &retries))
			goto retry;
	}
out:
	posix_acl_release(clone);
	return error;
}

/*
 * Extended attribute handlers
 */
static size_t
ext3_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
ext3_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
ext3_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 = ext3_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
ext3_xattr_get_acl_access(struct inode *inode, const char *name,
			  void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext3_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
}

static int
ext3_xattr_get_acl_default(struct inode *inode, const char *name,
			   void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext3_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
}

static int
ext3_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 = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
	if (IS_ERR(handle))
		return PTR_ERR(handle);
	error = ext3_set_acl(handle, inode, type, acl);
	ext3_journal_stop(handle);
	if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
		goto retry;

release_and_out:
	posix_acl_release(acl);
	return error;
}

static int
ext3_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 ext3_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
}

static int
ext3_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 ext3_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
}

struct xattr_handler ext3_xattr_acl_access_handler = {
	.prefix	= POSIX_ACL_XATTR_ACCESS,
	.list	= ext3_xattr_list_acl_access,
	.get	= ext3_xattr_get_acl_access,
	.set	= ext3_xattr_set_acl_access,
};

struct xattr_handler ext3_xattr_acl_default_handler = {
	.prefix	= POSIX_ACL_XATTR_DEFAULT,
	.list	= ext3_xattr_list_acl_default,
	.get	= ext3_xattr_get_acl_default,
	.set	= ext3_xattr_set_acl_default,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/ext3/acl.c
	3	*
	4	* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
	5	*/
	6
	7	#include <linux/init.h>
	8	#include <linux/sched.h>
	9	#include <linux/slab.h>
	10	#include <linux/fs.h>
	11	#include <linux/ext3_jbd.h>
	12	#include <linux/ext3_fs.h>
	13	#include "xattr.h"
	14	#include "acl.h"
	15
	16	/*
	17	* Convert from filesystem to in-memory representation.
	18	*/
	19	static struct posix_acl *
	20	ext3_acl_from_disk(const void *value, size_t size)
	21	{
	22	const char end = (char )value + size;
	23	int n, count;
	24	struct posix_acl *acl;
	25
	26	if (!value)
	27	return NULL;
	28	if (size < sizeof(ext3_acl_header))
	29	return ERR_PTR(-EINVAL);
	30	if (((ext3_acl_header *)value)->a_version !=
	31	cpu_to_le32(EXT3_ACL_VERSION))
	32	return ERR_PTR(-EINVAL);
	33	value = (char *)value + sizeof(ext3_acl_header);
	34	count = ext3_acl_count(size);
	35	if (count < 0)
	36	return ERR_PTR(-EINVAL);
	37	if (count == 0)
	38	return NULL;
	39	acl = posix_acl_alloc(count, GFP_KERNEL);
	40	if (!acl)
	41	return ERR_PTR(-ENOMEM);
	42	for (n=0; n < count; n++) {
	43	ext3_acl_entry *entry =
	44	(ext3_acl_entry *)value;
	45	if ((char *)value + sizeof(ext3_acl_entry_short) > end)
	46	goto fail;
	47	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	48	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
	49	switch(acl->a_entries[n].e_tag) {
	50	case ACL_USER_OBJ:
	51	case ACL_GROUP_OBJ:
	52	case ACL_MASK:
	53	case ACL_OTHER:
	54	value = (char *)value +
	55	sizeof(ext3_acl_entry_short);
	56	acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
	57	break;
	58
	59	case ACL_USER:
	60	case ACL_GROUP:
	61	value = (char *)value + sizeof(ext3_acl_entry);
	62	if ((char *)value > end)
	63	goto fail;
	64	acl->a_entries[n].e_id =
65	le32_to_cpu(entry->e_id);
66	break;
67
68	default:
69	goto fail;
70	}
71	}
72	if (value != end)
73	goto fail;
74	return acl;
75
76	fail:
77	posix_acl_release(acl);
78	return ERR_PTR(-EINVAL);
79	}
80
81	/*
82	* Convert from in-memory to filesystem representation.
83	*/
84	static void *
85	ext3_acl_to_disk(const struct posix_acl acl, size_t size)
86	{
87	ext3_acl_header *ext_acl;
88	char *e;
89	size_t n;
90
91	*size = ext3_acl_size(acl->a_count);
92	ext_acl = (ext3_acl_header *)kmalloc(sizeof(ext3_acl_header) +
93	acl->a_count * sizeof(ext3_acl_entry), GFP_KERNEL);
94	if (!ext_acl)
95	return ERR_PTR(-ENOMEM);
96	ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
97	e = (char *)ext_acl + sizeof(ext3_acl_header);
98	for (n=0; n < acl->a_count; n++) {
99	ext3_acl_entry entry = (ext3_acl_entry )e;
100	entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
101	entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
102	switch(acl->a_entries[n].e_tag) {
103	case ACL_USER:
104	case ACL_GROUP:
105	entry->e_id =
106	cpu_to_le32(acl->a_entries[n].e_id);
107	e += sizeof(ext3_acl_entry);
108	break;
109
110	case ACL_USER_OBJ:
111	case ACL_GROUP_OBJ:
112	case ACL_MASK:
113	case ACL_OTHER:
114	e += sizeof(ext3_acl_entry_short);
115	break;
116
117	default:
118	goto fail;
119	}
120	}
121	return (char *)ext_acl;
122
123	fail:
124	kfree(ext_acl);
125	return ERR_PTR(-EINVAL);
126	}
127
128	static inline struct posix_acl *
129	ext3_iget_acl(struct inode inode, struct posix_acl *i_acl)
130	{
131	struct posix_acl *acl = EXT3_ACL_NOT_CACHED;
132
133	spin_lock(&inode->i_lock);
134	if (*i_acl != EXT3_ACL_NOT_CACHED)
135	acl = posix_acl_dup(*i_acl);
136	spin_unlock(&inode->i_lock);
137
138	return acl;
139	}
140
141	static inline void
142	ext3_iset_acl(struct inode inode, struct posix_acl *i_acl,
143	struct posix_acl *acl)
144	{
145	spin_lock(&inode->i_lock);
146	if (*i_acl != EXT3_ACL_NOT_CACHED)
147	posix_acl_release(*i_acl);
148	*i_acl = posix_acl_dup(acl);
149	spin_unlock(&inode->i_lock);
150	}
151
152	/*
153	* Inode operation get_posix_acl().
154	*
1b1dcc1b	155	* inode->i_mutex: don't care
1da177e4 LT	156	*/
	157	static struct posix_acl *
	158	ext3_get_acl(struct inode *inode, int type)
	159	{
	160	struct ext3_inode_info *ei = EXT3_I(inode);
	161	int name_index;
	162	char *value = NULL;
	163	struct posix_acl *acl;
	164	int retval;
	165
	166	if (!test_opt(inode->i_sb, POSIX_ACL))
	167	return NULL;
	168
	169	switch(type) {
	170	case ACL_TYPE_ACCESS:
	171	acl = ext3_iget_acl(inode, &ei->i_acl);
	172	if (acl != EXT3_ACL_NOT_CACHED)
	173	return acl;
	174	name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
	175	break;
	176
	177	case ACL_TYPE_DEFAULT:
	178	acl = ext3_iget_acl(inode, &ei->i_default_acl);
	179	if (acl != EXT3_ACL_NOT_CACHED)
	180	return acl;
	181	name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
	182	break;
	183
	184	default:
	185	return ERR_PTR(-EINVAL);
	186	}
	187	retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
	188	if (retval > 0) {
	189	value = kmalloc(retval, GFP_KERNEL);
	190	if (!value)
	191	return ERR_PTR(-ENOMEM);
	192	retval = ext3_xattr_get(inode, name_index, "", value, retval);
	193	}
	194	if (retval > 0)
	195	acl = ext3_acl_from_disk(value, retval);
	196	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	197	acl = NULL;
	198	else
	199	acl = ERR_PTR(retval);
	200	kfree(value);
	201
	202	if (!IS_ERR(acl)) {
	203	switch(type) {
	204	case ACL_TYPE_ACCESS:
	205	ext3_iset_acl(inode, &ei->i_acl, acl);
	206	break;
	207
	208	case ACL_TYPE_DEFAULT:
	209	ext3_iset_acl(inode, &ei->i_default_acl, acl);
	210	break;
	211	}
	212	}
	213	return acl;
	214	}
	215
	216	/*
	217	* Set the access or default ACL of an inode.
	218	*
1b1dcc1b	219	* inode->i_mutex: down unless called from ext3_new_inode
1da177e4 LT	220	*/
	221	static int
	222	ext3_set_acl(handle_t handle, struct inode inode, int type,
	223	struct posix_acl *acl)
	224	{
	225	struct ext3_inode_info *ei = EXT3_I(inode);
	226	int name_index;
	227	void *value = NULL;
	228	size_t size;
	229	int error;
	230
	231	if (S_ISLNK(inode->i_mode))
	232	return -EOPNOTSUPP;
	233
	234	switch(type) {
	235	case ACL_TYPE_ACCESS:
	236	name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
	237	if (acl) {
	238	mode_t mode = inode->i_mode;
	239	error = posix_acl_equiv_mode(acl, &mode);
	240	if (error < 0)
	241	return error;
	242	else {
	243	inode->i_mode = mode;
	244	ext3_mark_inode_dirty(handle, inode);
	245	if (error == 0)
	246	acl = NULL;
	247	}
	248	}
	249	break;
	250
	251	case ACL_TYPE_DEFAULT:
	252	name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
	253	if (!S_ISDIR(inode->i_mode))
	254	return acl ? -EACCES : 0;
	255	break;
	256
	257	default:
	258	return -EINVAL;
	259	}
	260	if (acl) {
	261	value = ext3_acl_to_disk(acl, &size);
	262	if (IS_ERR(value))
	263	return (int)PTR_ERR(value);
	264	}
	265
	266	error = ext3_xattr_set_handle(handle, inode, name_index, "",
	267	value, size, 0);
	268
	269	kfree(value);
	270	if (!error) {
	271	switch(type) {
	272	case ACL_TYPE_ACCESS:
	273	ext3_iset_acl(inode, &ei->i_acl, acl);
	274	break;
	275
	276	case ACL_TYPE_DEFAULT:
	277	ext3_iset_acl(inode, &ei->i_default_acl, acl);
	278	break;
	279	}
	280	}
	281	return error;
	282	}
	283
284	static int
285	ext3_check_acl(struct inode *inode, int mask)
286	{
287	struct posix_acl *acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
288
e493073d	289	if (IS_ERR(acl))
e493073d	290	return PTR_ERR(acl);
1da177e4 LT	291	if (acl) {
	292	int error = posix_acl_permission(inode, acl, mask);
	293	posix_acl_release(acl);
	294	return error;
	295	}
	296
	297	return -EAGAIN;
	298	}
	299
	300	int
	301	ext3_permission(struct inode inode, int mask, struct nameidata nd)
	302	{
	303	return generic_permission(inode, mask, ext3_check_acl);
	304	}
	305
	306	/*
	307	* Initialize the ACLs of a new inode. Called from ext3_new_inode.
	308	*
1b1dcc1b JS	309	* dir->i_mutex: down
1b1dcc1b JS	310	* inode->i_mutex: up (access to inode is still exclusive)
1da177e4 LT	311	*/
	312	int
	313	ext3_init_acl(handle_t handle, struct inode inode, struct inode *dir)
	314	{
	315	struct posix_acl *acl = NULL;
	316	int error = 0;
	317
	318	if (!S_ISLNK(inode->i_mode)) {
	319	if (test_opt(dir->i_sb, POSIX_ACL)) {
	320	acl = ext3_get_acl(dir, ACL_TYPE_DEFAULT);
	321	if (IS_ERR(acl))
	322	return PTR_ERR(acl);
	323	}
	324	if (!acl)
	325	inode->i_mode &= ~current->fs->umask;
	326	}
	327	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
	328	struct posix_acl *clone;
	329	mode_t mode;
	330
	331	if (S_ISDIR(inode->i_mode)) {
	332	error = ext3_set_acl(handle, inode,
	333	ACL_TYPE_DEFAULT, acl);
	334	if (error)
	335	goto cleanup;
	336	}
	337	clone = posix_acl_clone(acl, GFP_KERNEL);
	338	error = -ENOMEM;
	339	if (!clone)
	340	goto cleanup;
	341
	342	mode = inode->i_mode;
	343	error = posix_acl_create_masq(clone, &mode);
	344	if (error >= 0) {
	345	inode->i_mode = mode;
	346	if (error > 0) {
	347	/* This is an extended ACL */
	348	error = ext3_set_acl(handle, inode,
	349	ACL_TYPE_ACCESS, clone);
	350	}
	351	}
	352	posix_acl_release(clone);
	353	}
	354	cleanup:
	355	posix_acl_release(acl);
	356	return error;
	357	}
	358
	359	/*
	360	* Does chmod for an inode that may have an Access Control List. The
	361	* inode->i_mode field must be updated to the desired value by the caller
	362	* before calling this function.
	363	* Returns 0 on success, or a negative error number.
	364	*
	365	* We change the ACL rather than storing some ACL entries in the file
	366	* mode permission bits (which would be more efficient), because that
	367	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
	368	* for directories) are added. There are no more bits available in the
	369	* file mode.
	370	*
1b1dcc1b	371	* inode->i_mutex: down
1da177e4 LT	372	*/
	373	int
	374	ext3_acl_chmod(struct inode *inode)
	375	{
	376	struct posix_acl acl, clone;
	377	int error;
	378
	379	if (S_ISLNK(inode->i_mode))
	380	return -EOPNOTSUPP;
	381	if (!test_opt(inode->i_sb, POSIX_ACL))
	382	return 0;
	383	acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
	384	if (IS_ERR(acl) \|\| !acl)
	385	return PTR_ERR(acl);
	386	clone = posix_acl_clone(acl, GFP_KERNEL);
	387	posix_acl_release(acl);
	388	if (!clone)
	389	return -ENOMEM;
	390	error = posix_acl_chmod_masq(clone, inode->i_mode);
	391	if (!error) {
	392	handle_t *handle;
	393	int retries = 0;
	394
	395	retry:
1f54587b JK	396	handle = ext3_journal_start(inode,
1f54587b JK	397	EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
1da177e4 LT	398	if (IS_ERR(handle)) {
	399	error = PTR_ERR(handle);
	400	ext3_std_error(inode->i_sb, error);
	401	goto out;
	402	}
	403	error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
	404	ext3_journal_stop(handle);
	405	if (error == -ENOSPC &&
	406	ext3_should_retry_alloc(inode->i_sb, &retries))
	407	goto retry;
	408	}
	409	out:
	410	posix_acl_release(clone);
	411	return error;
	412	}
	413
	414	/*
	415	* Extended attribute handlers
	416	*/
	417	static size_t
	418	ext3_xattr_list_acl_access(struct inode inode, char list, size_t list_len,
	419	const char *name, size_t name_len)
	420	{
9a59f452	421	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
1da177e4 LT	422
	423	if (!test_opt(inode->i_sb, POSIX_ACL))
	424	return 0;
	425	if (list && size <= list_len)
9a59f452	426	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
1da177e4 LT	427	return size;
	428	}
	429
	430	static size_t
	431	ext3_xattr_list_acl_default(struct inode inode, char list, size_t list_len,
	432	const char *name, size_t name_len)
	433	{
9a59f452	434	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
1da177e4 LT	435
	436	if (!test_opt(inode->i_sb, POSIX_ACL))
	437	return 0;
	438	if (list && size <= list_len)
9a59f452	439	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
1da177e4 LT	440	return size;
	441	}
	442
	443	static int
	444	ext3_xattr_get_acl(struct inode inode, int type, void buffer, size_t size)
	445	{
	446	struct posix_acl *acl;
	447	int error;
	448
	449	if (!test_opt(inode->i_sb, POSIX_ACL))
	450	return -EOPNOTSUPP;
	451
	452	acl = ext3_get_acl(inode, type);
	453	if (IS_ERR(acl))
	454	return PTR_ERR(acl);
	455	if (acl == NULL)
	456	return -ENODATA;
	457	error = posix_acl_to_xattr(acl, buffer, size);
	458	posix_acl_release(acl);
	459
	460	return error;
	461	}
	462
	463	static int
	464	ext3_xattr_get_acl_access(struct inode inode, const char name,
	465	void *buffer, size_t size)
	466	{
	467	if (strcmp(name, "") != 0)
	468	return -EINVAL;
	469	return ext3_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
	470	}
	471
	472	static int
	473	ext3_xattr_get_acl_default(struct inode inode, const char name,
	474	void *buffer, size_t size)
	475	{
	476	if (strcmp(name, "") != 0)
	477	return -EINVAL;
	478	return ext3_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
	479	}
	480
	481	static int
	482	ext3_xattr_set_acl(struct inode inode, int type, const void value,
	483	size_t size)
	484	{
	485	handle_t *handle;
	486	struct posix_acl *acl;
	487	int error, retries = 0;
	488
	489	if (!test_opt(inode->i_sb, POSIX_ACL))
	490	return -EOPNOTSUPP;
	491	if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
	492	return -EPERM;
	493
	494	if (value) {
	495	acl = posix_acl_from_xattr(value, size);
	496	if (IS_ERR(acl))
	497	return PTR_ERR(acl);
	498	else if (acl) {
	499	error = posix_acl_valid(acl);
	500	if (error)
	501	goto release_and_out;
	502	}
	503	} else
504	acl = NULL;
505
506	retry:
1f54587b	507	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
1da177e4 LT	508	if (IS_ERR(handle))
	509	return PTR_ERR(handle);
	510	error = ext3_set_acl(handle, inode, type, acl);
	511	ext3_journal_stop(handle);
	512	if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
	513	goto retry;
	514
	515	release_and_out:
	516	posix_acl_release(acl);
	517	return error;
	518	}
	519
	520	static int
	521	ext3_xattr_set_acl_access(struct inode inode, const char name,
	522	const void *value, size_t size, int flags)
	523	{
	524	if (strcmp(name, "") != 0)
	525	return -EINVAL;
	526	return ext3_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
	527	}
	528
	529	static int
	530	ext3_xattr_set_acl_default(struct inode inode, const char name,
	531	const void *value, size_t size, int flags)
	532	{
	533	if (strcmp(name, "") != 0)
	534	return -EINVAL;
	535	return ext3_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
	536	}
	537
	538	struct xattr_handler ext3_xattr_acl_access_handler = {
9a59f452	539	.prefix = POSIX_ACL_XATTR_ACCESS,
1da177e4 LT	540	.list = ext3_xattr_list_acl_access,
	541	.get = ext3_xattr_get_acl_access,
	542	.set = ext3_xattr_set_acl_access,
	543	};
	544
	545	struct xattr_handler ext3_xattr_acl_default_handler = {
9a59f452	546	.prefix = POSIX_ACL_XATTR_DEFAULT,
1da177e4 LT	547	.list = ext3_xattr_list_acl_default,
	548	.get = ext3_xattr_get_acl_default,
	549	.set = ext3_xattr_set_acl_default,
	550	};