[net-next-2.6.git] / fs / ext2 / acl.c

/*
 * linux/fs/ext2/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 "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_sem: 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);
	if (value)
		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_sem: 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;
	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);

	if (value)
		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_sem: down
 * inode->i_sem: 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_sem: 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, <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 "ext2.h"
	12	#include "xattr.h"
	13	#include "acl.h"
	14
	15	/*
	16	* Convert from filesystem to in-memory representation.
	17	*/
	18	static struct posix_acl *
	19	ext2_acl_from_disk(const void *value, size_t size)
	20	{
	21	const char end = (char )value + size;
	22	int n, count;
	23	struct posix_acl *acl;
	24
	25	if (!value)
	26	return NULL;
	27	if (size < sizeof(ext2_acl_header))
	28	return ERR_PTR(-EINVAL);
	29	if (((ext2_acl_header *)value)->a_version !=
	30	cpu_to_le32(EXT2_ACL_VERSION))
	31	return ERR_PTR(-EINVAL);
	32	value = (char *)value + sizeof(ext2_acl_header);
	33	count = ext2_acl_count(size);
	34	if (count < 0)
	35	return ERR_PTR(-EINVAL);
	36	if (count == 0)
	37	return NULL;
	38	acl = posix_acl_alloc(count, GFP_KERNEL);
	39	if (!acl)
	40	return ERR_PTR(-ENOMEM);
	41	for (n=0; n < count; n++) {
	42	ext2_acl_entry *entry =
	43	(ext2_acl_entry *)value;
	44	if ((char *)value + sizeof(ext2_acl_entry_short) > end)
	45	goto fail;
	46	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	47	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
	48	switch(acl->a_entries[n].e_tag) {
	49	case ACL_USER_OBJ:
	50	case ACL_GROUP_OBJ:
	51	case ACL_MASK:
	52	case ACL_OTHER:
	53	value = (char *)value +
	54	sizeof(ext2_acl_entry_short);
	55	acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
	56	break;
	57
	58	case ACL_USER:
	59	case ACL_GROUP:
	60	value = (char *)value + sizeof(ext2_acl_entry);
	61	if ((char *)value > end)
	62	goto fail;
	63	acl->a_entries[n].e_id =
	64	le32_to_cpu(entry->e_id);
65	break;
66
67	default:
68	goto fail;
69	}
70	}
71	if (value != end)
72	goto fail;
73	return acl;
74
75	fail:
76	posix_acl_release(acl);
77	return ERR_PTR(-EINVAL);
78	}
79
80	/*
81	* Convert from in-memory to filesystem representation.
82	*/
83	static void *
84	ext2_acl_to_disk(const struct posix_acl acl, size_t size)
85	{
86	ext2_acl_header *ext_acl;
87	char *e;
88	size_t n;
89
90	*size = ext2_acl_size(acl->a_count);
91	ext_acl = (ext2_acl_header *)kmalloc(sizeof(ext2_acl_header) +
92	acl->a_count * sizeof(ext2_acl_entry), GFP_KERNEL);
93	if (!ext_acl)
94	return ERR_PTR(-ENOMEM);
95	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
96	e = (char *)ext_acl + sizeof(ext2_acl_header);
97	for (n=0; n < acl->a_count; n++) {
98	ext2_acl_entry entry = (ext2_acl_entry )e;
99	entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
100	entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
101	switch(acl->a_entries[n].e_tag) {
102	case ACL_USER:
103	case ACL_GROUP:
104	entry->e_id =
105	cpu_to_le32(acl->a_entries[n].e_id);
106	e += sizeof(ext2_acl_entry);
107	break;
108
109	case ACL_USER_OBJ:
110	case ACL_GROUP_OBJ:
111	case ACL_MASK:
112	case ACL_OTHER:
113	e += sizeof(ext2_acl_entry_short);
114	break;
115
116	default:
117	goto fail;
118	}
119	}
120	return (char *)ext_acl;
121
122	fail:
123	kfree(ext_acl);
124	return ERR_PTR(-EINVAL);
125	}
126
127	static inline struct posix_acl *
128	ext2_iget_acl(struct inode inode, struct posix_acl *i_acl)
129	{
130	struct posix_acl *acl = EXT2_ACL_NOT_CACHED;
131
132	spin_lock(&inode->i_lock);
133	if (*i_acl != EXT2_ACL_NOT_CACHED)
134	acl = posix_acl_dup(*i_acl);
135	spin_unlock(&inode->i_lock);
136
137	return acl;
138	}
139
140	static inline void
141	ext2_iset_acl(struct inode inode, struct posix_acl *i_acl,
142	struct posix_acl *acl)
143	{
144	spin_lock(&inode->i_lock);
145	if (*i_acl != EXT2_ACL_NOT_CACHED)
146	posix_acl_release(*i_acl);
147	*i_acl = posix_acl_dup(acl);
148	spin_unlock(&inode->i_lock);
149	}
150
151	/*
152	* inode->i_sem: don't care
153	*/
154	static struct posix_acl *
155	ext2_get_acl(struct inode *inode, int type)
156	{
157	struct ext2_inode_info *ei = EXT2_I(inode);
158	int name_index;
159	char *value = NULL;
160	struct posix_acl *acl;
161	int retval;
162
163	if (!test_opt(inode->i_sb, POSIX_ACL))
164	return NULL;
165
166	switch(type) {
167	case ACL_TYPE_ACCESS:
168	acl = ext2_iget_acl(inode, &ei->i_acl);
169	if (acl != EXT2_ACL_NOT_CACHED)
170	return acl;
171	name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
172	break;
173
174	case ACL_TYPE_DEFAULT:
175	acl = ext2_iget_acl(inode, &ei->i_default_acl);
176	if (acl != EXT2_ACL_NOT_CACHED)
177	return acl;
178	name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
179	break;
180
181	default:
182	return ERR_PTR(-EINVAL);
183	}
184	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
185	if (retval > 0) {
186	value = kmalloc(retval, GFP_KERNEL);
187	if (!value)
188	return ERR_PTR(-ENOMEM);
189	retval = ext2_xattr_get(inode, name_index, "", value, retval);
190	}
191	if (retval > 0)
192	acl = ext2_acl_from_disk(value, retval);
193	else if (retval == -ENODATA \|\| retval == -ENOSYS)
194	acl = NULL;
195	else
196	acl = ERR_PTR(retval);
197	if (value)
198	kfree(value);
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	/*
215	* inode->i_sem: down
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;
223	size_t size;
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
265	if (value)
266	kfree(value);
267	if (!error) {
268	switch(type) {
269	case ACL_TYPE_ACCESS:
270	ext2_iset_acl(inode, &ei->i_acl, acl);
271	break;
272
273	case ACL_TYPE_DEFAULT:
274	ext2_iset_acl(inode, &ei->i_default_acl, acl);
275	break;
276	}
277	}
278	return error;
279	}
280
281	static int
282	ext2_check_acl(struct inode *inode, int mask)
283	{
284	struct posix_acl *acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
285
e493073d AM	286	if (IS_ERR(acl))
e493073d AM	287	return PTR_ERR(acl);
1da177e4 LT	288	if (acl) {
	289	int error = posix_acl_permission(inode, acl, mask);
	290	posix_acl_release(acl);
	291	return error;
	292	}
	293
	294	return -EAGAIN;
	295	}
	296
	297	int
	298	ext2_permission(struct inode inode, int mask, struct nameidata nd)
	299	{
	300	return generic_permission(inode, mask, ext2_check_acl);
	301	}
	302
	303	/*
	304	* Initialize the ACLs of a new inode. Called from ext2_new_inode.
	305	*
	306	* dir->i_sem: down
	307	* inode->i_sem: up (access to inode is still exclusive)
	308	*/
	309	int
	310	ext2_init_acl(struct inode inode, struct inode dir)
	311	{
	312	struct posix_acl *acl = NULL;
	313	int error = 0;
	314
	315	if (!S_ISLNK(inode->i_mode)) {
	316	if (test_opt(dir->i_sb, POSIX_ACL)) {
	317	acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT);
	318	if (IS_ERR(acl))
	319	return PTR_ERR(acl);
	320	}
	321	if (!acl)
	322	inode->i_mode &= ~current->fs->umask;
	323	}
	324	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
	325	struct posix_acl *clone;
	326	mode_t mode;
	327
	328	if (S_ISDIR(inode->i_mode)) {
	329	error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
	330	if (error)
	331	goto cleanup;
	332	}
	333	clone = posix_acl_clone(acl, GFP_KERNEL);
	334	error = -ENOMEM;
	335	if (!clone)
	336	goto cleanup;
	337	mode = inode->i_mode;
	338	error = posix_acl_create_masq(clone, &mode);
	339	if (error >= 0) {
	340	inode->i_mode = mode;
	341	if (error > 0) {
	342	/* This is an extended ACL */
	343	error = ext2_set_acl(inode,
	344	ACL_TYPE_ACCESS, clone);
	345	}
	346	}
	347	posix_acl_release(clone);
	348	}
	349	cleanup:
	350	posix_acl_release(acl);
	351	return error;
352	}
353
354	/*
355	* Does chmod for an inode that may have an Access Control List. The
356	* inode->i_mode field must be updated to the desired value by the caller
357	* before calling this function.
358	* Returns 0 on success, or a negative error number.
359	*
360	* We change the ACL rather than storing some ACL entries in the file
361	* mode permission bits (which would be more efficient), because that
362	* would break once additional permissions (like ACL_APPEND, ACL_DELETE
363	* for directories) are added. There are no more bits available in the
364	* file mode.
365	*
366	* inode->i_sem: down
367	*/
368	int
369	ext2_acl_chmod(struct inode *inode)
370	{
371	struct posix_acl acl, clone;
372	int error;
373
374	if (!test_opt(inode->i_sb, POSIX_ACL))
375	return 0;
376	if (S_ISLNK(inode->i_mode))
377	return -EOPNOTSUPP;
378	acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
379	if (IS_ERR(acl) \|\| !acl)
380	return PTR_ERR(acl);
381	clone = posix_acl_clone(acl, GFP_KERNEL);
382	posix_acl_release(acl);
383	if (!clone)
384	return -ENOMEM;
385	error = posix_acl_chmod_masq(clone, inode->i_mode);
386	if (!error)
387	error = ext2_set_acl(inode, ACL_TYPE_ACCESS, clone);
388	posix_acl_release(clone);
389	return error;
390	}
391
392	/*
393	* Extended attribut handlers
394	*/
395	static size_t
396	ext2_xattr_list_acl_access(struct inode inode, char list, size_t list_size,
397	const char *name, size_t name_len)
398	{
9a59f452	399	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
1da177e4 LT	400
	401	if (!test_opt(inode->i_sb, POSIX_ACL))
	402	return 0;
	403	if (list && size <= list_size)
9a59f452	404	memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
1da177e4 LT	405	return size;
	406	}
	407
	408	static size_t
	409	ext2_xattr_list_acl_default(struct inode inode, char list, size_t list_size,
	410	const char *name, size_t name_len)
	411	{
9a59f452	412	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
1da177e4 LT	413
	414	if (!test_opt(inode->i_sb, POSIX_ACL))
	415	return 0;
	416	if (list && size <= list_size)
9a59f452	417	memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
1da177e4 LT	418	return size;
	419	}
	420
	421	static int
	422	ext2_xattr_get_acl(struct inode inode, int type, void buffer, size_t size)
	423	{
	424	struct posix_acl *acl;
	425	int error;
	426
	427	if (!test_opt(inode->i_sb, POSIX_ACL))
	428	return -EOPNOTSUPP;
	429
	430	acl = ext2_get_acl(inode, type);
	431	if (IS_ERR(acl))
	432	return PTR_ERR(acl);
	433	if (acl == NULL)
	434	return -ENODATA;
	435	error = posix_acl_to_xattr(acl, buffer, size);
	436	posix_acl_release(acl);
	437
	438	return error;
	439	}
	440
	441	static int
	442	ext2_xattr_get_acl_access(struct inode inode, const char name,
	443	void *buffer, size_t size)
	444	{
	445	if (strcmp(name, "") != 0)
	446	return -EINVAL;
	447	return ext2_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
	448	}
	449
	450	static int
	451	ext2_xattr_get_acl_default(struct inode inode, const char name,
	452	void *buffer, size_t size)
	453	{
	454	if (strcmp(name, "") != 0)
	455	return -EINVAL;
	456	return ext2_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
	457	}
	458
	459	static int
	460	ext2_xattr_set_acl(struct inode inode, int type, const void value,
	461	size_t size)
	462	{
	463	struct posix_acl *acl;
	464	int error;
	465
	466	if (!test_opt(inode->i_sb, POSIX_ACL))
	467	return -EOPNOTSUPP;
	468	if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
	469	return -EPERM;
	470
	471	if (value) {
	472	acl = posix_acl_from_xattr(value, size);
	473	if (IS_ERR(acl))
	474	return PTR_ERR(acl);
	475	else if (acl) {
	476	error = posix_acl_valid(acl);
	477	if (error)
	478	goto release_and_out;
	479	}
	480	} else
	481	acl = NULL;
482
483	error = ext2_set_acl(inode, type, acl);
484
485	release_and_out:
486	posix_acl_release(acl);
487	return error;
488	}
489
490	static int
491	ext2_xattr_set_acl_access(struct inode inode, const char name,
492	const void *value, size_t size, int flags)
493	{
494	if (strcmp(name, "") != 0)
495	return -EINVAL;
496	return ext2_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
497	}
498
499	static int
500	ext2_xattr_set_acl_default(struct inode inode, const char name,
501	const void *value, size_t size, int flags)
502	{
503	if (strcmp(name, "") != 0)
504	return -EINVAL;
505	return ext2_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
506	}
507
508	struct xattr_handler ext2_xattr_acl_access_handler = {
9a59f452	509	.prefix = POSIX_ACL_XATTR_ACCESS,
1da177e4 LT	510	.list = ext2_xattr_list_acl_access,
	511	.get = ext2_xattr_get_acl_access,
	512	.set = ext2_xattr_set_acl_access,
	513	};
	514
	515	struct xattr_handler ext2_xattr_acl_default_handler = {
9a59f452	516	.prefix = POSIX_ACL_XATTR_DEFAULT,
1da177e4 LT	517	.list = ext2_xattr_list_acl_default,
	518	.get = ext2_xattr_get_acl_default,
	519	.set = ext2_xattr_set_acl_default,
	520	};