[linux.git] / fs / ext2 / acl.c

/*
 * linux/fs/ext2/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
 */

#include <linux/capability.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include "ext2.h"
#include "xattr.h"
#include "acl.h"

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *
ext2_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(ext2_acl_header))
		 return ERR_PTR(-EINVAL);
	if (((ext2_acl_header *)value)->a_version !=
	    cpu_to_le32(EXT2_ACL_VERSION))
		return ERR_PTR(-EINVAL);
	value = (char *)value + sizeof(ext2_acl_header);
	count = ext2_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++) {
		ext2_acl_entry *entry =
			(ext2_acl_entry *)value;
		if ((char *)value + sizeof(ext2_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(ext2_acl_entry_short);
				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
				break;

			case ACL_USER:
			case ACL_GROUP:
				value = (char *)value + sizeof(ext2_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 *
ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
	ext2_acl_header *ext_acl;
	char *e;
	size_t n;

	*size = ext2_acl_size(acl->a_count);
	ext_acl = (ext2_acl_header *)kmalloc(sizeof(ext2_acl_header) +
		acl->a_count * sizeof(ext2_acl_entry), GFP_KERNEL);
	if (!ext_acl)
		return ERR_PTR(-ENOMEM);
	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
	e = (char *)ext_acl + sizeof(ext2_acl_header);
	for (n=0; n < acl->a_count; n++) {
		ext2_acl_entry *entry = (ext2_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(ext2_acl_entry);
				break;

			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				e += sizeof(ext2_acl_entry_short);
				break;

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

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

static inline struct posix_acl *
ext2_iget_acl(struct inode *inode, struct posix_acl **i_acl)
{
	struct posix_acl *acl = EXT2_ACL_NOT_CACHED;

	spin_lock(&inode->i_lock);
	if (*i_acl != EXT2_ACL_NOT_CACHED)
		acl = posix_acl_dup(*i_acl);
	spin_unlock(&inode->i_lock);

	return acl;
}

static inline void
ext2_iset_acl(struct inode *inode, struct posix_acl **i_acl,
		   struct posix_acl *acl)
{
	spin_lock(&inode->i_lock);
	if (*i_acl != EXT2_ACL_NOT_CACHED)
		posix_acl_release(*i_acl);
	*i_acl = posix_acl_dup(acl);
	spin_unlock(&inode->i_lock);
}

/*
 * inode->i_mutex: don't care
 */
static struct posix_acl *
ext2_get_acl(struct inode *inode, int type)
{
	struct ext2_inode_info *ei = EXT2_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 = ext2_iget_acl(inode, &ei->i_acl);
			if (acl != EXT2_ACL_NOT_CACHED)
				return acl;
			name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
			break;

		case ACL_TYPE_DEFAULT:
			acl = ext2_iget_acl(inode, &ei->i_default_acl);
			if (acl != EXT2_ACL_NOT_CACHED)
				return acl;
			name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
			break;

		default:
			return ERR_PTR(-EINVAL);
	}
	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_KERNEL);
		if (!value)
			return ERR_PTR(-ENOMEM);
		retval = ext2_xattr_get(inode, name_index, "", value, retval);
	}
	if (retval > 0)
		acl = ext2_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:
				ext2_iset_acl(inode, &ei->i_acl, acl);
				break;

			case ACL_TYPE_DEFAULT:
				ext2_iset_acl(inode, &ei->i_default_acl, acl);
				break;
		}
	}
	return acl;
}

/*
 * inode->i_mutex: down
 */
static int
ext2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
	struct ext2_inode_info *ei = EXT2_I(inode);
	int name_index;
	void *value = NULL;
	size_t size = 0;
	int error;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;

	switch(type) {
		case ACL_TYPE_ACCESS:
			name_index = EXT2_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;
					mark_inode_dirty(inode);
					if (error == 0)
						acl = NULL;
				}
			}
			break;

		case ACL_TYPE_DEFAULT:
			name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
			if (!S_ISDIR(inode->i_mode))
				return acl ? -EACCES : 0;
			break;

		default:
			return -EINVAL;
	}
 	if (acl) {
		value = ext2_acl_to_disk(acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext2_xattr_set(inode, name_index, "", value, size, 0);

	kfree(value);
	if (!error) {
		switch(type) {
			case ACL_TYPE_ACCESS:
				ext2_iset_acl(inode, &ei->i_acl, acl);
				break;

			case ACL_TYPE_DEFAULT:
				ext2_iset_acl(inode, &ei->i_default_acl, acl);
				break;
		}
	}
	return error;
}

static int
ext2_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl = ext2_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
ext2_permission(struct inode *inode, int mask, struct nameidata *nd)
{
	return generic_permission(inode, mask, ext2_check_acl);
}

/*
 * Initialize the ACLs of a new inode. Called from ext2_new_inode.
 *
 * dir->i_mutex: down
 * inode->i_mutex: up (access to inode is still exclusive)
 */
int
ext2_init_acl(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 = ext2_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 = ext2_set_acl(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 = ext2_set_acl(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
ext2_acl_chmod(struct inode *inode)
{
	struct posix_acl *acl, *clone;
        int error;

	if (!test_opt(inode->i_sb, POSIX_ACL))
		return 0;
	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	acl = ext2_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)
		error = ext2_set_acl(inode, ACL_TYPE_ACCESS, clone);
	posix_acl_release(clone);
	return error;
}

/*
 * Extended attribut handlers
 */
static size_t
ext2_xattr_list_acl_access(struct inode *inode, char *list, size_t list_size,
			   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_size)
		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
	return size;
}

static size_t
ext2_xattr_list_acl_default(struct inode *inode, char *list, size_t list_size,
			    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_size)
		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
	return size;
}

static int
ext2_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 = ext2_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
ext2_xattr_get_acl_access(struct inode *inode, const char *name,
			  void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext2_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
}

static int
ext2_xattr_get_acl_default(struct inode *inode, const char *name,
			   void *buffer, size_t size)
{
	if (strcmp(name, "") != 0)
		return -EINVAL;
	return ext2_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
}

static int
ext2_xattr_set_acl(struct inode *inode, int type, const void *value,
		   size_t size)
{
	struct posix_acl *acl;
	int error;

	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;

	error = ext2_set_acl(inode, type, acl);

release_and_out:
	posix_acl_release(acl);
	return error;
}

static int
ext2_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 ext2_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
}

static int
ext2_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 ext2_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
}

struct xattr_handler ext2_xattr_acl_access_handler = {
	.prefix	= POSIX_ACL_XATTR_ACCESS,
	.list	= ext2_xattr_list_acl_access,
	.get	= ext2_xattr_get_acl_access,
	.set	= ext2_xattr_set_acl_access,
};

struct xattr_handler ext2_xattr_acl_default_handler = {
	.prefix	= POSIX_ACL_XATTR_DEFAULT,
	.list	= ext2_xattr_list_acl_default,
	.get	= ext2_xattr_get_acl_default,
	.set	= ext2_xattr_set_acl_default,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/ext2/acl.c
	3	*
	4	* Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
	5	*/
	6
16f7e0fe	7	#include <linux/capability.h>
1da177e4 LT	8	#include <linux/init.h>
	9	#include <linux/sched.h>
	10	#include <linux/slab.h>
	11	#include <linux/fs.h>
	12	#include "ext2.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	ext2_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(ext2_acl_header))
	29	return ERR_PTR(-EINVAL);
	30	if (((ext2_acl_header *)value)->a_version !=
	31	cpu_to_le32(EXT2_ACL_VERSION))
	32	return ERR_PTR(-EINVAL);
	33	value = (char *)value + sizeof(ext2_acl_header);
	34	count = ext2_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	ext2_acl_entry *entry =
	44	(ext2_acl_entry *)value;
	45	if ((char *)value + sizeof(ext2_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(ext2_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(ext2_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	ext2_acl_to_disk(const struct posix_acl acl, size_t size)
86	{
87	ext2_acl_header *ext_acl;
88	char *e;
89	size_t n;
90
91	*size = ext2_acl_size(acl->a_count);
92	ext_acl = (ext2_acl_header *)kmalloc(sizeof(ext2_acl_header) +
93	acl->a_count * sizeof(ext2_acl_entry), GFP_KERNEL);
94	if (!ext_acl)
95	return ERR_PTR(-ENOMEM);
96	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
97	e = (char *)ext_acl + sizeof(ext2_acl_header);
98	for (n=0; n < acl->a_count; n++) {
99	ext2_acl_entry entry = (ext2_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(ext2_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(ext2_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	ext2_iget_acl(struct inode inode, struct posix_acl *i_acl)
130	{
131	struct posix_acl *acl = EXT2_ACL_NOT_CACHED;
132
133	spin_lock(&inode->i_lock);
134	if (*i_acl != EXT2_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	ext2_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 != EXT2_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	/*
1b1dcc1b	153	* inode->i_mutex: don't care
1da177e4 LT	154	*/
	155	static struct posix_acl *
	156	ext2_get_acl(struct inode *inode, int type)
	157	{
	158	struct ext2_inode_info *ei = EXT2_I(inode);
	159	int name_index;
	160	char *value = NULL;
	161	struct posix_acl *acl;
	162	int retval;
	163
	164	if (!test_opt(inode->i_sb, POSIX_ACL))
	165	return NULL;
	166
	167	switch(type) {
	168	case ACL_TYPE_ACCESS:
	169	acl = ext2_iget_acl(inode, &ei->i_acl);
	170	if (acl != EXT2_ACL_NOT_CACHED)
	171	return acl;
	172	name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
	173	break;
	174
	175	case ACL_TYPE_DEFAULT:
	176	acl = ext2_iget_acl(inode, &ei->i_default_acl);
	177	if (acl != EXT2_ACL_NOT_CACHED)
	178	return acl;
	179	name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
	180	break;
	181
	182	default:
	183	return ERR_PTR(-EINVAL);
	184	}
	185	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
	186	if (retval > 0) {
	187	value = kmalloc(retval, GFP_KERNEL);
	188	if (!value)
	189	return ERR_PTR(-ENOMEM);
	190	retval = ext2_xattr_get(inode, name_index, "", value, retval);
	191	}
	192	if (retval > 0)
	193	acl = ext2_acl_from_disk(value, retval);
	194	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	195	acl = NULL;
	196	else
	197	acl = ERR_PTR(retval);
f99d49ad	198	kfree(value);
1da177e4 LT	199
	200	if (!IS_ERR(acl)) {
	201	switch(type) {
	202	case ACL_TYPE_ACCESS:
	203	ext2_iset_acl(inode, &ei->i_acl, acl);
	204	break;
	205
	206	case ACL_TYPE_DEFAULT:
	207	ext2_iset_acl(inode, &ei->i_default_acl, acl);
	208	break;
	209	}
	210	}
	211	return acl;
	212	}
	213
	214	/*
1b1dcc1b	215	* inode->i_mutex: down
1da177e4 LT	216	*/
	217	static int
	218	ext2_set_acl(struct inode inode, int type, struct posix_acl acl)
	219	{
	220	struct ext2_inode_info *ei = EXT2_I(inode);
	221	int name_index;
	222	void *value = NULL;
dfa08592	223	size_t size = 0;
1da177e4 LT	224	int error;
	225
	226	if (S_ISLNK(inode->i_mode))
	227	return -EOPNOTSUPP;
	228	if (!test_opt(inode->i_sb, POSIX_ACL))
	229	return 0;
	230
	231	switch(type) {
	232	case ACL_TYPE_ACCESS:
	233	name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
	234	if (acl) {
	235	mode_t mode = inode->i_mode;
	236	error = posix_acl_equiv_mode(acl, &mode);
	237	if (error < 0)
	238	return error;
	239	else {
	240	inode->i_mode = mode;
	241	mark_inode_dirty(inode);
	242	if (error == 0)
	243	acl = NULL;
	244	}
	245	}
	246	break;
	247
	248	case ACL_TYPE_DEFAULT:
	249	name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
	250	if (!S_ISDIR(inode->i_mode))
	251	return acl ? -EACCES : 0;
	252	break;
	253
	254	default:
	255	return -EINVAL;
	256	}
	257	if (acl) {
	258	value = ext2_acl_to_disk(acl, &size);
	259	if (IS_ERR(value))
	260	return (int)PTR_ERR(value);
	261	}
	262
	263	error = ext2_xattr_set(inode, name_index, "", value, size, 0);
	264
f99d49ad	265	kfree(value);
1da177e4 LT	266	if (!error) {
	267	switch(type) {
	268	case ACL_TYPE_ACCESS:
	269	ext2_iset_acl(inode, &ei->i_acl, acl);
	270	break;
	271
	272	case ACL_TYPE_DEFAULT:
	273	ext2_iset_acl(inode, &ei->i_default_acl, acl);
	274	break;
	275	}
	276	}
	277	return error;
	278	}
	279
	280	static int
	281	ext2_check_acl(struct inode *inode, int mask)
	282	{
	283	struct posix_acl *acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
	284
e493073d	285	if (IS_ERR(acl))
e493073d	286	return PTR_ERR(acl);
1da177e4 LT	287	if (acl) {
	288	int error = posix_acl_permission(inode, acl, mask);
	289	posix_acl_release(acl);
	290	return error;
	291	}
	292
	293	return -EAGAIN;
	294	}
	295
	296	int
	297	ext2_permission(struct inode inode, int mask, struct nameidata nd)
	298	{
	299	return generic_permission(inode, mask, ext2_check_acl);
	300	}
	301
	302	/*
	303	* Initialize the ACLs of a new inode. Called from ext2_new_inode.
	304	*
1b1dcc1b JS	305	* dir->i_mutex: down
1b1dcc1b JS	306	* inode->i_mutex: up (access to inode is still exclusive)
1da177e4 LT	307	*/
	308	int
	309	ext2_init_acl(struct inode inode, struct inode dir)
	310	{
	311	struct posix_acl *acl = NULL;
	312	int error = 0;
	313
	314	if (!S_ISLNK(inode->i_mode)) {
	315	if (test_opt(dir->i_sb, POSIX_ACL)) {
	316	acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT);
	317	if (IS_ERR(acl))
	318	return PTR_ERR(acl);
	319	}
	320	if (!acl)
	321	inode->i_mode &= ~current->fs->umask;
	322	}
	323	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
	324	struct posix_acl *clone;
	325	mode_t mode;
	326
	327	if (S_ISDIR(inode->i_mode)) {
	328	error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
	329	if (error)
	330	goto cleanup;
	331	}
	332	clone = posix_acl_clone(acl, GFP_KERNEL);
	333	error = -ENOMEM;
	334	if (!clone)
	335	goto cleanup;
	336	mode = inode->i_mode;
	337	error = posix_acl_create_masq(clone, &mode);
	338	if (error >= 0) {
	339	inode->i_mode = mode;
	340	if (error > 0) {
	341	/* This is an extended ACL */
	342	error = ext2_set_acl(inode,
	343	ACL_TYPE_ACCESS, clone);
	344	}
	345	}
	346	posix_acl_release(clone);
	347	}
	348	cleanup:
	349	posix_acl_release(acl);
	350	return error;
	351	}
	352
	353	/*
	354	* Does chmod for an inode that may have an Access Control List. The
	355	* inode->i_mode field must be updated to the desired value by the caller
	356	* before calling this function.
	357	* Returns 0 on success, or a negative error number.
	358	*
	359	* We change the ACL rather than storing some ACL entries in the file
	360	* mode permission bits (which would be more efficient), because that
	361	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
	362	* for directories) are added. There are no more bits available in the
	363	* file mode.
	364	*
1b1dcc1b	365	* inode->i_mutex: down
1da177e4 LT	366	*/
	367	int
	368	ext2_acl_chmod(struct inode *inode)
	369	{
	370	struct posix_acl acl, clone;
	371	int error;
	372
	373	if (!test_opt(inode->i_sb, POSIX_ACL))
	374	return 0;
	375	if (S_ISLNK(inode->i_mode))
	376	return -EOPNOTSUPP;
	377	acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
	378	if (IS_ERR(acl) \|\| !acl)
	379	return PTR_ERR(acl);
	380	clone = posix_acl_clone(acl, GFP_KERNEL);
	381	posix_acl_release(acl);
	382	if (!clone)
	383	return -ENOMEM;
	384	error = posix_acl_chmod_masq(clone, inode->i_mode);
	385	if (!error)
	386	error = ext2_set_acl(inode, ACL_TYPE_ACCESS, clone);
	387	posix_acl_release(clone);
	388	return error;
	389	}
	390
	391	/*
	392	* Extended attribut handlers
	393	*/
	394	static size_t
	395	ext2_xattr_list_acl_access(struct inode inode, char list, size_t list_size,
	396	const char *name, size_t name_len)
	397	{
9a59f452	398	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
1da177e4 LT	399
	400	if (!test_opt(inode->i_sb, POSIX_ACL))
	401	return 0;
	402	if (list && size <= list_size)
9a59f452	403	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
1da177e4 LT	404	return size;
	405	}
	406
	407	static size_t
	408	ext2_xattr_list_acl_default(struct inode inode, char list, size_t list_size,
	409	const char *name, size_t name_len)
	410	{
9a59f452	411	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
1da177e4 LT	412
	413	if (!test_opt(inode->i_sb, POSIX_ACL))
	414	return 0;
	415	if (list && size <= list_size)
9a59f452	416	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
1da177e4 LT	417	return size;
	418	}
	419
	420	static int
	421	ext2_xattr_get_acl(struct inode inode, int type, void buffer, size_t size)
	422	{
	423	struct posix_acl *acl;
	424	int error;
	425
	426	if (!test_opt(inode->i_sb, POSIX_ACL))
	427	return -EOPNOTSUPP;
	428
	429	acl = ext2_get_acl(inode, type);
	430	if (IS_ERR(acl))
	431	return PTR_ERR(acl);
	432	if (acl == NULL)
	433	return -ENODATA;
	434	error = posix_acl_to_xattr(acl, buffer, size);
	435	posix_acl_release(acl);
	436
	437	return error;
	438	}
	439
	440	static int
	441	ext2_xattr_get_acl_access(struct inode inode, const char name,
	442	void *buffer, size_t size)
	443	{
	444	if (strcmp(name, "") != 0)
	445	return -EINVAL;
	446	return ext2_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
	447	}
	448
	449	static int
	450	ext2_xattr_get_acl_default(struct inode inode, const char name,
	451	void *buffer, size_t size)
	452	{
	453	if (strcmp(name, "") != 0)
	454	return -EINVAL;
	455	return ext2_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
	456	}
	457
	458	static int
	459	ext2_xattr_set_acl(struct inode inode, int type, const void value,
	460	size_t size)
	461	{
	462	struct posix_acl *acl;
	463	int error;
	464
	465	if (!test_opt(inode->i_sb, POSIX_ACL))
	466	return -EOPNOTSUPP;
	467	if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
	468	return -EPERM;
	469
	470	if (value) {
	471	acl = posix_acl_from_xattr(value, size);
	472	if (IS_ERR(acl))
	473	return PTR_ERR(acl);
	474	else if (acl) {
	475	error = posix_acl_valid(acl);
	476	if (error)
	477	goto release_and_out;
	478	}
	479	} else
	480	acl = NULL;
481
482	error = ext2_set_acl(inode, type, acl);
483
484	release_and_out:
485	posix_acl_release(acl);
486	return error;
487	}
488
489	static int
490	ext2_xattr_set_acl_access(struct inode inode, const char name,
491	const void *value, size_t size, int flags)
492	{
493	if (strcmp(name, "") != 0)
494	return -EINVAL;
495	return ext2_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
496	}
497
498	static int
499	ext2_xattr_set_acl_default(struct inode inode, const char name,
500	const void *value, size_t size, int flags)
501	{
502	if (strcmp(name, "") != 0)
503	return -EINVAL;
504	return ext2_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
505	}
506
507	struct xattr_handler ext2_xattr_acl_access_handler = {
9a59f452	508	.prefix = POSIX_ACL_XATTR_ACCESS,
1da177e4 LT	509	.list = ext2_xattr_list_acl_access,
	510	.get = ext2_xattr_get_acl_access,
	511	.set = ext2_xattr_set_acl_access,
	512	};
	513
	514	struct xattr_handler ext2_xattr_acl_default_handler = {
9a59f452	515	.prefix = POSIX_ACL_XATTR_DEFAULT,
1da177e4 LT	516	.list = ext2_xattr_list_acl_default,
	517	.get = ext2_xattr_get_acl_default,
	518	.set = ext2_xattr_set_acl_default,
	519	};