[mirror_ubuntu-bionic-kernel.git] / fs / ext4 / acl.c

/*
 * linux/fs/ext4/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/capability.h>
#include <linux/fs.h>
#include "ext4_jbd2.h"
#include "ext4.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_NOFS);
	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);
			break;

		case ACL_USER:
			value = (char *)value + sizeof(ext4_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(ext4_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 *
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_NOFS);
	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++) {
		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
		ext4_acl_entry *entry = (ext4_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(ext4_acl_entry);
			break;
		case ACL_GROUP:
			entry->e_id = cpu_to_le32(
				from_kgid(&init_user_ns, acl_e->e_gid));
			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);
}

/*
 * Inode operation get_posix_acl().
 *
 * inode->i_mutex: don't care
 */
struct posix_acl *
ext4_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 = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_NOFS);
		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))
		set_cached_acl(inode, type, acl);

	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)
{
	int name_index;
	void *value = NULL;
	size_t size = 0;
	int error;

	switch (type) {
	case ACL_TYPE_ACCESS:
		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
		if (acl) {
			error = posix_acl_equiv_mode(acl, &inode->i_mode);
			if (error < 0)
				return error;
			else {
				inode->i_ctime = ext4_current_time(inode);
				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)
		set_cached_acl(inode, type, acl);

	return error;
}

int
ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	handle_t *handle;
	int error, retries = 0;

retry:
	handle = ext4_journal_start(inode, EXT4_HT_XATTR,
				    ext4_jbd2_credits_xattr(inode));
	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;
	return error;
}

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

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

	if (default_acl) {
		error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
				       default_acl);
		posix_acl_release(default_acl);
	}
	if (acl) {
		if (!error)
			error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
					       acl);
		posix_acl_release(acl);
	}
	return error;
}
Commit	Line	Data
ac27a0ec	1	/*
617ba13b	2	* linux/fs/ext4/acl.c
ac27a0ec DK	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/capability.h>
	11	#include <linux/fs.h>
3dcf5451 CH	12	#include "ext4_jbd2.h"
3dcf5451 CH	13	#include "ext4.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;
216553c4	40	acl = posix_acl_alloc(count, GFP_NOFS);
ac27a0ec DK	41	if (!acl)
ac27a0ec DK	42	return ERR_PTR(-ENOMEM);
2b2d6d01	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);
2b2d6d01 TT	50
	51	switch (acl->a_entries[n].e_tag) {
	52	case ACL_USER_OBJ:
	53	case ACL_GROUP_OBJ:
	54	case ACL_MASK:
	55	case ACL_OTHER:
	56	value = (char *)value +
	57	sizeof(ext4_acl_entry_short);
2b2d6d01 TT	58	break;
	59
	60	case ACL_USER:
af84df93 EB	61	value = (char *)value + sizeof(ext4_acl_entry);
	62	if ((char *)value > end)
	63	goto fail;
	64	acl->a_entries[n].e_uid =
	65	make_kuid(&init_user_ns,
	66	le32_to_cpu(entry->e_id));
	67	break;
2b2d6d01 TT	68	case ACL_GROUP:
	69	value = (char *)value + sizeof(ext4_acl_entry);
	70	if ((char *)value > end)
ac27a0ec	71	goto fail;
af84df93 EB	72	acl->a_entries[n].e_gid =
	73	make_kgid(&init_user_ns,
	74	le32_to_cpu(entry->e_id));
2b2d6d01 TT	75	break;
	76
	77	default:
	78	goto fail;
ac27a0ec DK	79	}
	80	}
	81	if (value != end)
	82	goto fail;
	83	return acl;
	84
	85	fail:
	86	posix_acl_release(acl);
	87	return ERR_PTR(-EINVAL);
	88	}
	89
	90	/*
	91	* Convert from in-memory to filesystem representation.
	92	*/
	93	static void *
617ba13b	94	ext4_acl_to_disk(const struct posix_acl acl, size_t size)
ac27a0ec	95	{
617ba13b	96	ext4_acl_header *ext_acl;
ac27a0ec DK	97	char *e;
	98	size_t n;
	99
617ba13b MC	100	*size = ext4_acl_size(acl->a_count);
617ba13b MC	101	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
216553c4	102	sizeof(ext4_acl_entry), GFP_NOFS);
ac27a0ec DK	103	if (!ext_acl)
ac27a0ec DK	104	return ERR_PTR(-ENOMEM);
617ba13b MC	105	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
617ba13b MC	106	e = (char *)ext_acl + sizeof(ext4_acl_header);
2b2d6d01	107	for (n = 0; n < acl->a_count; n++) {
af84df93	108	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
617ba13b	109	ext4_acl_entry entry = (ext4_acl_entry )e;
af84df93 EB	110	entry->e_tag = cpu_to_le16(acl_e->e_tag);
	111	entry->e_perm = cpu_to_le16(acl_e->e_perm);
	112	switch (acl_e->e_tag) {
2b2d6d01	113	case ACL_USER:
af84df93 EB	114	entry->e_id = cpu_to_le32(
	115	from_kuid(&init_user_ns, acl_e->e_uid));
	116	e += sizeof(ext4_acl_entry);
	117	break;
2b2d6d01	118	case ACL_GROUP:
af84df93 EB	119	entry->e_id = cpu_to_le32(
af84df93 EB	120	from_kgid(&init_user_ns, acl_e->e_gid));
2b2d6d01 TT	121	e += sizeof(ext4_acl_entry);
	122	break;
	123
	124	case ACL_USER_OBJ:
	125	case ACL_GROUP_OBJ:
	126	case ACL_MASK:
	127	case ACL_OTHER:
	128	e += sizeof(ext4_acl_entry_short);
	129	break;
	130
	131	default:
	132	goto fail;
ac27a0ec DK	133	}
	134	}
	135	return (char *)ext_acl;
	136
	137	fail:
	138	kfree(ext_acl);
	139	return ERR_PTR(-EINVAL);
	140	}
	141
ac27a0ec DK	142	/*
	143	* Inode operation get_posix_acl().
	144	*
	145	* inode->i_mutex: don't care
	146	*/
4e34e719	147	struct posix_acl *
617ba13b	148	ext4_get_acl(struct inode *inode, int type)
ac27a0ec	149	{
ac27a0ec DK	150	int name_index;
	151	char *value = NULL;
	152	struct posix_acl *acl;
	153	int retval;
	154
2b2d6d01 TT	155	switch (type) {
2b2d6d01 TT	156	case ACL_TYPE_ACCESS:
2b2d6d01 TT	157	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
2b2d6d01 TT	158	break;
2b2d6d01	159	case ACL_TYPE_DEFAULT:
2b2d6d01 TT	160	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
2b2d6d01 TT	161	break;
2b2d6d01	162	default:
073aaa1b	163	BUG();
ac27a0ec	164	}
617ba13b	165	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
ac27a0ec	166	if (retval > 0) {
216553c4	167	value = kmalloc(retval, GFP_NOFS);
ac27a0ec DK	168	if (!value)
ac27a0ec DK	169	return ERR_PTR(-ENOMEM);
617ba13b	170	retval = ext4_xattr_get(inode, name_index, "", value, retval);
ac27a0ec DK	171	}
ac27a0ec DK	172	if (retval > 0)
617ba13b	173	acl = ext4_acl_from_disk(value, retval);
ac27a0ec DK	174	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	175	acl = NULL;
	176	else
	177	acl = ERR_PTR(retval);
	178	kfree(value);
	179
073aaa1b AV	180	if (!IS_ERR(acl))
073aaa1b AV	181	set_cached_acl(inode, type, acl);
2b2d6d01	182
ac27a0ec DK	183	return acl;
	184	}
	185
	186	/*
	187	* Set the access or default ACL of an inode.
	188	*
617ba13b	189	* inode->i_mutex: down unless called from ext4_new_inode
ac27a0ec DK	190	*/
ac27a0ec DK	191	static int
64e178a7	192	__ext4_set_acl(handle_t handle, struct inode inode, int type,
ac27a0ec DK	193	struct posix_acl *acl)
ac27a0ec DK	194	{
ac27a0ec DK	195	int name_index;
	196	void *value = NULL;
	197	size_t size = 0;
	198	int error;
	199
2b2d6d01 TT	200	switch (type) {
	201	case ACL_TYPE_ACCESS:
	202	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
	203	if (acl) {
d6952123	204	error = posix_acl_equiv_mode(acl, &inode->i_mode);
2b2d6d01 TT	205	if (error < 0)
	206	return error;
	207	else {
c6ac12a6	208	inode->i_ctime = ext4_current_time(inode);
2b2d6d01 TT	209	ext4_mark_inode_dirty(handle, inode);
	210	if (error == 0)
	211	acl = NULL;
ac27a0ec	212	}
2b2d6d01 TT	213	}
2b2d6d01 TT	214	break;
ac27a0ec	215
2b2d6d01 TT	216	case ACL_TYPE_DEFAULT:
	217	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
	218	if (!S_ISDIR(inode->i_mode))
	219	return acl ? -EACCES : 0;
	220	break;
ac27a0ec	221
2b2d6d01 TT	222	default:
2b2d6d01 TT	223	return -EINVAL;
ac27a0ec DK	224	}
ac27a0ec DK	225	if (acl) {
617ba13b	226	value = ext4_acl_to_disk(acl, &size);
ac27a0ec DK	227	if (IS_ERR(value))
	228	return (int)PTR_ERR(value);
	229	}
	230
617ba13b	231	error = ext4_xattr_set_handle(handle, inode, name_index, "",
ac27a0ec DK	232	value, size, 0);
	233
	234	kfree(value);
073aaa1b AV	235	if (!error)
073aaa1b AV	236	set_cached_acl(inode, type, acl);
2b2d6d01	237
ac27a0ec DK	238	return error;
	239	}
	240
ac27a0ec	241	int
64e178a7	242	ext4_set_acl(struct inode inode, struct posix_acl acl, int type)
ac27a0ec	243	{
bc26ab5f	244	handle_t *handle;
64e178a7	245	int error, retries = 0;
bc26ab5f	246
bc26ab5f	247	retry:
9924a92a	248	handle = ext4_journal_start(inode, EXT4_HT_XATTR,
95eaefbd	249	ext4_jbd2_credits_xattr(inode));
64e178a7 CH	250	if (IS_ERR(handle))
	251	return PTR_ERR(handle);
	252
	253	error = __ext4_set_acl(handle, inode, type, acl);
bc26ab5f	254	ext4_journal_stop(handle);
64e178a7	255	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
bc26ab5f	256	goto retry;
ac27a0ec DK	257	return error;
	258	}
	259
	260	/*
64e178a7 CH	261	* Initialize the ACLs of a new inode. Called from ext4_new_inode.
	262	*
	263	* dir->i_mutex: down
	264	* inode->i_mutex: up (access to inode is still exclusive)
ac27a0ec	265	*/
64e178a7 CH	266	int
64e178a7 CH	267	ext4_init_acl(handle_t handle, struct inode inode, struct inode *dir)
ac27a0ec	268	{
64e178a7	269	struct posix_acl default_acl, acl;
ac27a0ec DK	270	int error;
ac27a0ec DK	271
64e178a7 CH	272	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	273	if (error)
	274	return error;
ac27a0ec	275
64e178a7 CH	276	if (default_acl) {
	277	error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
	278	default_acl);
	279	posix_acl_release(default_acl);
	280	}
	281	if (acl) {
	282	if (!error)
	283	error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
	284	acl);
	285	posix_acl_release(acl);
24ec19b0	286	}
ac27a0ec DK	287	return error;
ac27a0ec DK	288	}