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

// SPDX-License-Identifier: GPL-2.0
/*
 * linux/fs/ext2/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
 */

#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);
				break;

			case ACL_USER:
				value = (char *)value + sizeof(ext2_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_uid =
					make_kuid(&init_user_ns,
						  le32_to_cpu(entry->e_id));
				break;
			case ACL_GROUP:
				value = (char *)value + sizeof(ext2_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_gid =
					make_kgid(&init_user_ns,
						  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 = 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++) {
		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
		ext2_acl_entry *entry = (ext2_acl_entry *)e;
		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
		entry->e_perm = cpu_to_le16(acl_e->e_perm);
		switch(acl_e->e_tag) {
			case ACL_USER:
				entry->e_id = cpu_to_le32(
					from_kuid(&init_user_ns, acl_e->e_uid));
				e += sizeof(ext2_acl_entry);
				break;
			case ACL_GROUP:
				entry->e_id = cpu_to_le32(
					from_kgid(&init_user_ns, acl_e->e_gid));
				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);
}

/*
 * inode->i_mutex: don't care
 */
struct posix_acl *
ext2_get_acl(struct inode *inode, int type)
{
	int name_index;
	char *value = NULL;
	struct posix_acl *acl;
	int retval;

	switch (type) {
	case ACL_TYPE_ACCESS:
		name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	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);

	return acl;
}

static int
__ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	int name_index;
	void *value = NULL;
	size_t size = 0;
	int error;

	switch(type) {
		case ACL_TYPE_ACCESS:
			name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
			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)
		set_cached_acl(inode, type, acl);
	return error;
}

/*
 * inode->i_mutex: down
 */
int
ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	int error;
	int update_mode = 0;
	umode_t mode = inode->i_mode;

	if (type == ACL_TYPE_ACCESS && acl) {
		error = posix_acl_update_mode(inode, &mode, &acl);
		if (error)
			return error;
		update_mode = 1;
	}
	error = __ext2_set_acl(inode, acl, type);
	if (!error && update_mode) {
		inode->i_mode = mode;
		inode->i_ctime = current_time(inode);
		mark_inode_dirty(inode);
	}
	return error;
}

/*
 * 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 *default_acl, *acl;
	int error;

	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	if (error)
		return error;

	if (default_acl) {
		error = __ext2_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
		posix_acl_release(default_acl);
	} else {
		inode->i_default_acl = NULL;
	}
	if (acl) {
		if (!error)
			error = __ext2_set_acl(inode, acl, ACL_TYPE_ACCESS);
		posix_acl_release(acl);
	} else {
		inode->i_acl = NULL;
	}
	return error;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/ext2/acl.c
	4	*
	5	* Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
	6	*/
	7
	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);
1da177e4 LT	56	break;
	57
	58	case ACL_USER:
af84df93 EB	59	value = (char *)value + sizeof(ext2_acl_entry);
	60	if ((char *)value > end)
	61	goto fail;
	62	acl->a_entries[n].e_uid =
	63	make_kuid(&init_user_ns,
	64	le32_to_cpu(entry->e_id));
	65	break;
1da177e4 LT	66	case ACL_GROUP:
	67	value = (char *)value + sizeof(ext2_acl_entry);
	68	if ((char *)value > end)
	69	goto fail;
af84df93 EB	70	acl->a_entries[n].e_gid =
	71	make_kgid(&init_user_ns,
	72	le32_to_cpu(entry->e_id));
1da177e4 LT	73	break;
	74
	75	default:
	76	goto fail;
	77	}
	78	}
	79	if (value != end)
	80	goto fail;
	81	return acl;
	82
	83	fail:
	84	posix_acl_release(acl);
	85	return ERR_PTR(-EINVAL);
	86	}
	87
	88	/*
	89	* Convert from in-memory to filesystem representation.
	90	*/
	91	static void *
	92	ext2_acl_to_disk(const struct posix_acl acl, size_t size)
	93	{
	94	ext2_acl_header *ext_acl;
	95	char *e;
	96	size_t n;
	97
	98	*size = ext2_acl_size(acl->a_count);
f52720ca PI	99	ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
f52720ca PI	100	sizeof(ext2_acl_entry), GFP_KERNEL);
1da177e4 LT	101	if (!ext_acl)
	102	return ERR_PTR(-ENOMEM);
	103	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
	104	e = (char *)ext_acl + sizeof(ext2_acl_header);
	105	for (n=0; n < acl->a_count; n++) {
af84df93	106	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
1da177e4	107	ext2_acl_entry entry = (ext2_acl_entry )e;
af84df93 EB	108	entry->e_tag = cpu_to_le16(acl_e->e_tag);
	109	entry->e_perm = cpu_to_le16(acl_e->e_perm);
	110	switch(acl_e->e_tag) {
1da177e4	111	case ACL_USER:
af84df93 EB	112	entry->e_id = cpu_to_le32(
	113	from_kuid(&init_user_ns, acl_e->e_uid));
	114	e += sizeof(ext2_acl_entry);
	115	break;
1da177e4	116	case ACL_GROUP:
af84df93 EB	117	entry->e_id = cpu_to_le32(
af84df93 EB	118	from_kgid(&init_user_ns, acl_e->e_gid));
1da177e4 LT	119	e += sizeof(ext2_acl_entry);
	120	break;
	121
	122	case ACL_USER_OBJ:
	123	case ACL_GROUP_OBJ:
	124	case ACL_MASK:
	125	case ACL_OTHER:
	126	e += sizeof(ext2_acl_entry_short);
	127	break;
	128
	129	default:
	130	goto fail;
	131	}
	132	}
	133	return (char *)ext_acl;
	134
	135	fail:
	136	kfree(ext_acl);
	137	return ERR_PTR(-EINVAL);
	138	}
	139
1da177e4	140	/*
1b1dcc1b	141	* inode->i_mutex: don't care
1da177e4	142	*/
4e34e719	143	struct posix_acl *
1da177e4 LT	144	ext2_get_acl(struct inode *inode, int type)
1da177e4 LT	145	{
1da177e4 LT	146	int name_index;
	147	char *value = NULL;
	148	struct posix_acl *acl;
	149	int retval;
	150
073aaa1b AV	151	switch (type) {
	152	case ACL_TYPE_ACCESS:
	153	name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
	154	break;
	155	case ACL_TYPE_DEFAULT:
	156	name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
	157	break;
	158	default:
	159	BUG();
1da177e4 LT	160	}
	161	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
	162	if (retval > 0) {
	163	value = kmalloc(retval, GFP_KERNEL);
	164	if (!value)
	165	return ERR_PTR(-ENOMEM);
	166	retval = ext2_xattr_get(inode, name_index, "", value, retval);
	167	}
	168	if (retval > 0)
	169	acl = ext2_acl_from_disk(value, retval);
	170	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	171	acl = NULL;
	172	else
	173	acl = ERR_PTR(retval);
f99d49ad	174	kfree(value);
1da177e4	175
1da177e4 LT	176	return acl;
	177	}
	178
a992f2d3 JK	179	static int
a992f2d3 JK	180	__ext2_set_acl(struct inode inode, struct posix_acl acl, int type)
1da177e4	181	{
1da177e4 LT	182	int name_index;
1da177e4 LT	183	void *value = NULL;
dfa08592	184	size_t size = 0;
1da177e4 LT	185	int error;
1da177e4 LT	186
1da177e4 LT	187	switch(type) {
	188	case ACL_TYPE_ACCESS:
	189	name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
1da177e4 LT	190	break;
	191
	192	case ACL_TYPE_DEFAULT:
	193	name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
	194	if (!S_ISDIR(inode->i_mode))
	195	return acl ? -EACCES : 0;
	196	break;
	197
	198	default:
	199	return -EINVAL;
	200	}
	201	if (acl) {
	202	value = ext2_acl_to_disk(acl, &size);
	203	if (IS_ERR(value))
	204	return (int)PTR_ERR(value);
	205	}
	206
	207	error = ext2_xattr_set(inode, name_index, "", value, size, 0);
	208
f99d49ad	209	kfree(value);
073aaa1b AV	210	if (!error)
073aaa1b AV	211	set_cached_acl(inode, type, acl);
1da177e4 LT	212	return error;
	213	}
	214
a992f2d3 JK	215	/*
	216	* inode->i_mutex: down
	217	*/
	218	int
	219	ext2_set_acl(struct inode inode, struct posix_acl acl, int type)
	220	{
	221	int error;
fe26569e EF	222	int update_mode = 0;
fe26569e EF	223	umode_t mode = inode->i_mode;
a992f2d3 JK	224
a992f2d3 JK	225	if (type == ACL_TYPE_ACCESS && acl) {
fe26569e	226	error = posix_acl_update_mode(inode, &mode, &acl);
a992f2d3 JK	227	if (error)
a992f2d3 JK	228	return error;
fe26569e EF	229	update_mode = 1;
	230	}
	231	error = __ext2_set_acl(inode, acl, type);
	232	if (!error && update_mode) {
	233	inode->i_mode = mode;
a992f2d3 JK	234	inode->i_ctime = current_time(inode);
	235	mark_inode_dirty(inode);
	236	}
fe26569e	237	return error;
a992f2d3 JK	238	}
a992f2d3 JK	239
1da177e4 LT	240	/*
	241	* Initialize the ACLs of a new inode. Called from ext2_new_inode.
	242	*
1b1dcc1b JS	243	* dir->i_mutex: down
1b1dcc1b JS	244	* inode->i_mutex: up (access to inode is still exclusive)
1da177e4 LT	245	*/
	246	int
	247	ext2_init_acl(struct inode inode, struct inode dir)
	248	{
64e178a7 CH	249	struct posix_acl default_acl, acl;
64e178a7 CH	250	int error;
1da177e4	251
64e178a7	252	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
bc26ab5f AV	253	if (error)
bc26ab5f AV	254	return error;
1da177e4	255
64e178a7	256	if (default_acl) {
a992f2d3	257	error = __ext2_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
64e178a7	258	posix_acl_release(default_acl);
59fed3bf CX	259	} else {
59fed3bf CX	260	inode->i_default_acl = NULL;
64e178a7 CH	261	}
	262	if (acl) {
	263	if (!error)
a992f2d3	264	error = __ext2_set_acl(inode, acl, ACL_TYPE_ACCESS);
64e178a7	265	posix_acl_release(acl);
59fed3bf CX	266	} else {
59fed3bf CX	267	inode->i_acl = NULL;
64e178a7	268	}
1da177e4 LT	269	return error;
1da177e4 LT	270	}