[mirror_ubuntu-artful-kernel.git] / fs / jffs2 / acl.c

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2006  NEC Corporation
 *
 * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/crc32.h>
#include <linux/jffs2.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/mtd/mtd.h>
#include "nodelist.h"

static size_t jffs2_acl_size(int count)
{
	if (count <= 4) {
		return sizeof(struct jffs2_acl_header)
		       + count * sizeof(struct jffs2_acl_entry_short);
	} else {
		return sizeof(struct jffs2_acl_header)
		       + 4 * sizeof(struct jffs2_acl_entry_short)
		       + (count - 4) * sizeof(struct jffs2_acl_entry);
	}
}

static int jffs2_acl_count(size_t size)
{
	size_t s;

	size -= sizeof(struct jffs2_acl_header);
	if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
		if (size % sizeof(struct jffs2_acl_entry_short))
			return -1;
		return size / sizeof(struct jffs2_acl_entry_short);
	} else {
		s = size - 4 * sizeof(struct jffs2_acl_entry_short);
		if (s % sizeof(struct jffs2_acl_entry))
			return -1;
		return s / sizeof(struct jffs2_acl_entry) + 4;
	}
}

static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
{
	void *end = value + size;
	struct jffs2_acl_header *header = value;
	struct jffs2_acl_entry *entry;
	struct posix_acl *acl;
	uint32_t ver;
	int i, count;

	if (!value)
		return NULL;
	if (size < sizeof(struct jffs2_acl_header))
		return ERR_PTR(-EINVAL);
	ver = je32_to_cpu(header->a_version);
	if (ver != JFFS2_ACL_VERSION) {
		JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
		return ERR_PTR(-EINVAL);
	}

	value += sizeof(struct jffs2_acl_header);
	count = jffs2_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 (i=0; i < count; i++) {
		entry = value;
		if (value + sizeof(struct jffs2_acl_entry_short) > end)
			goto fail;
		acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
		acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
		switch (acl->a_entries[i].e_tag) {
			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				value += sizeof(struct jffs2_acl_entry_short);
				break;

			case ACL_USER:
				value += sizeof(struct jffs2_acl_entry);
				if (value > end)
					goto fail;
				acl->a_entries[i].e_uid =
					make_kuid(&init_user_ns,
						  je32_to_cpu(entry->e_id));
				break;
			case ACL_GROUP:
				value += sizeof(struct jffs2_acl_entry);
				if (value > end)
					goto fail;
				acl->a_entries[i].e_gid =
					make_kgid(&init_user_ns,
						  je32_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);
}

static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
{
	struct jffs2_acl_header *header;
	struct jffs2_acl_entry *entry;
	void *e;
	size_t i;

	*size = jffs2_acl_size(acl->a_count);
	header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
	if (!header)
		return ERR_PTR(-ENOMEM);
	header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
	e = header + 1;
	for (i=0; i < acl->a_count; i++) {
		const struct posix_acl_entry *acl_e = &acl->a_entries[i];
		entry = e;
		entry->e_tag = cpu_to_je16(acl_e->e_tag);
		entry->e_perm = cpu_to_je16(acl_e->e_perm);
		switch(acl_e->e_tag) {
			case ACL_USER:
				entry->e_id = cpu_to_je32(
					from_kuid(&init_user_ns, acl_e->e_uid));
				e += sizeof(struct jffs2_acl_entry);
				break;
			case ACL_GROUP:
				entry->e_id = cpu_to_je32(
					from_kgid(&init_user_ns, acl_e->e_gid));
				e += sizeof(struct jffs2_acl_entry);
				break;

			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				e += sizeof(struct jffs2_acl_entry_short);
				break;

			default:
				goto fail;
		}
	}
	return header;
 fail:
	kfree(header);
	return ERR_PTR(-EINVAL);
}

struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
{
	struct posix_acl *acl;
	char *value = NULL;
	int rc, xprefix;

	switch (type) {
	case ACL_TYPE_ACCESS:
		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
	if (rc > 0) {
		value = kmalloc(rc, GFP_KERNEL);
		if (!value)
			return ERR_PTR(-ENOMEM);
		rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
	}
	if (rc > 0) {
		acl = jffs2_acl_from_medium(value, rc);
	} else if (rc == -ENODATA || rc == -ENOSYS) {
		acl = NULL;
	} else {
		acl = ERR_PTR(rc);
	}
	kfree(value);
	return acl;
}

static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
{
	char *value = NULL;
	size_t size = 0;
	int rc;

	if (acl) {
		value = jffs2_acl_to_medium(acl, &size);
		if (IS_ERR(value))
			return PTR_ERR(value);
	}
	rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
	if (!value && rc == -ENODATA)
		rc = 0;
	kfree(value);

	return rc;
}

int jffs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	int rc, xprefix;

	switch (type) {
	case ACL_TYPE_ACCESS:
		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
		if (acl) {
			umode_t mode;

			rc = posix_acl_update_mode(inode, &mode, &acl);
			if (rc)
				return rc;
			if (inode->i_mode != mode) {
				struct iattr attr;

				attr.ia_valid = ATTR_MODE | ATTR_CTIME;
				attr.ia_mode = mode;
				attr.ia_ctime = current_time(inode);
				rc = jffs2_do_setattr(inode, &attr);
				if (rc < 0)
					return rc;
			}
		}
		break;
	case ACL_TYPE_DEFAULT:
		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EACCES : 0;
		break;
	default:
		return -EINVAL;
	}
	rc = __jffs2_set_acl(inode, xprefix, acl);
	if (!rc)
		set_cached_acl(inode, type, acl);
	return rc;
}

int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode)
{
	struct posix_acl *default_acl, *acl;
	int rc;

	cache_no_acl(inode);

	rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl);
	if (rc)
		return rc;

	if (default_acl) {
		set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
		posix_acl_release(default_acl);
	}
	if (acl) {
		set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
		posix_acl_release(acl);
	}
	return 0;
}

int jffs2_init_acl_post(struct inode *inode)
{
	int rc;

	if (inode->i_default_acl) {
		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
		if (rc)
			return rc;
	}

	if (inode->i_acl) {
		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
		if (rc)
			return rc;
	}

	return 0;
}
Commit	Line	Data
652ecc20 KK	1	/*
652ecc20 KK	2	* JFFS2 -- Journalling Flash File System, Version 2.
aa98d7cf	3	*
c00c310e	4	* Copyright © 2006 NEC Corporation
aa98d7cf	5	*
652ecc20 KK	6	* Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
	7	*
	8	* For licensing information, see the file 'LICENCE' in this directory.
	9	*
	10	*/
c00c310e	11
5a528957 JP	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
5a528957 JP	13
aa98d7cf KK	14	#include <linux/kernel.h>
	15	#include <linux/slab.h>
	16	#include <linux/fs.h>
914e2637	17	#include <linux/sched.h>
aa98d7cf KK	18	#include <linux/time.h>
	19	#include <linux/crc32.h>
	20	#include <linux/jffs2.h>
	21	#include <linux/xattr.h>
	22	#include <linux/posix_acl_xattr.h>
	23	#include <linux/mtd/mtd.h>
	24	#include "nodelist.h"
	25
	26	static size_t jffs2_acl_size(int count)
	27	{
	28	if (count <= 4) {
de1f72fa KK	29	return sizeof(struct jffs2_acl_header)
de1f72fa KK	30	+ count * sizeof(struct jffs2_acl_entry_short);
aa98d7cf	31	} else {
de1f72fa KK	32	return sizeof(struct jffs2_acl_header)
	33	+ 4 * sizeof(struct jffs2_acl_entry_short)
	34	+ (count - 4) * sizeof(struct jffs2_acl_entry);
aa98d7cf KK	35	}
	36	}
	37
	38	static int jffs2_acl_count(size_t size)
	39	{
	40	size_t s;
	41
de1f72fa	42	size -= sizeof(struct jffs2_acl_header);
fc371a25	43	if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
de1f72fa	44	if (size % sizeof(struct jffs2_acl_entry_short))
aa98d7cf	45	return -1;
de1f72fa	46	return size / sizeof(struct jffs2_acl_entry_short);
aa98d7cf	47	} else {
fc371a25	48	s = size - 4 * sizeof(struct jffs2_acl_entry_short);
de1f72fa	49	if (s % sizeof(struct jffs2_acl_entry))
aa98d7cf	50	return -1;
de1f72fa	51	return s / sizeof(struct jffs2_acl_entry) + 4;
aa98d7cf KK	52	}
	53	}
	54
dea80134	55	static struct posix_acl jffs2_acl_from_medium(void value, size_t size)
aa98d7cf	56	{
dea80134 KK	57	void *end = value + size;
	58	struct jffs2_acl_header *header = value;
	59	struct jffs2_acl_entry *entry;
aa98d7cf KK	60	struct posix_acl *acl;
	61	uint32_t ver;
	62	int i, count;
	63
	64	if (!value)
	65	return NULL;
de1f72fa	66	if (size < sizeof(struct jffs2_acl_header))
aa98d7cf	67	return ERR_PTR(-EINVAL);
dea80134	68	ver = je32_to_cpu(header->a_version);
aa98d7cf KK	69	if (ver != JFFS2_ACL_VERSION) {
	70	JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
	71	return ERR_PTR(-EINVAL);
	72	}
	73
dea80134	74	value += sizeof(struct jffs2_acl_header);
aa98d7cf KK	75	count = jffs2_acl_count(size);
	76	if (count < 0)
	77	return ERR_PTR(-EINVAL);
	78	if (count == 0)
	79	return NULL;
	80
	81	acl = posix_acl_alloc(count, GFP_KERNEL);
	82	if (!acl)
	83	return ERR_PTR(-ENOMEM);
	84
	85	for (i=0; i < count; i++) {
dea80134 KK	86	entry = value;
dea80134 KK	87	if (value + sizeof(struct jffs2_acl_entry_short) > end)
aa98d7cf KK	88	goto fail;
	89	acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
	90	acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
	91	switch (acl->a_entries[i].e_tag) {
	92	case ACL_USER_OBJ:
	93	case ACL_GROUP_OBJ:
	94	case ACL_MASK:
	95	case ACL_OTHER:
dea80134	96	value += sizeof(struct jffs2_acl_entry_short);
aa98d7cf KK	97	break;
	98
	99	case ACL_USER:
0cfe53d3 EB	100	value += sizeof(struct jffs2_acl_entry);
	101	if (value > end)
	102	goto fail;
	103	acl->a_entries[i].e_uid =
	104	make_kuid(&init_user_ns,
	105	je32_to_cpu(entry->e_id));
	106	break;
aa98d7cf	107	case ACL_GROUP:
dea80134 KK	108	value += sizeof(struct jffs2_acl_entry);
dea80134 KK	109	if (value > end)
aa98d7cf	110	goto fail;
0cfe53d3 EB	111	acl->a_entries[i].e_gid =
	112	make_kgid(&init_user_ns,
	113	je32_to_cpu(entry->e_id));
aa98d7cf KK	114	break;
	115
	116	default:
	117	goto fail;
	118	}
	119	}
	120	if (value != end)
	121	goto fail;
	122	return acl;
	123	fail:
	124	posix_acl_release(acl);
	125	return ERR_PTR(-EINVAL);
	126	}
	127
	128	static void jffs2_acl_to_medium(const struct posix_acl acl, size_t *size)
	129	{
dea80134 KK	130	struct jffs2_acl_header *header;
	131	struct jffs2_acl_entry *entry;
	132	void *e;
aa98d7cf KK	133	size_t i;
	134
	135	*size = jffs2_acl_size(acl->a_count);
dea80134 KK	136	header = kmalloc(sizeof(header) + acl->a_count sizeof(*entry), GFP_KERNEL);
dea80134 KK	137	if (!header)
aa98d7cf	138	return ERR_PTR(-ENOMEM);
dea80134 KK	139	header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
dea80134 KK	140	e = header + 1;
aa98d7cf	141	for (i=0; i < acl->a_count; i++) {
0cfe53d3	142	const struct posix_acl_entry *acl_e = &acl->a_entries[i];
dea80134	143	entry = e;
0cfe53d3 EB	144	entry->e_tag = cpu_to_je16(acl_e->e_tag);
	145	entry->e_perm = cpu_to_je16(acl_e->e_perm);
	146	switch(acl_e->e_tag) {
aa98d7cf	147	case ACL_USER:
0cfe53d3 EB	148	entry->e_id = cpu_to_je32(
	149	from_kuid(&init_user_ns, acl_e->e_uid));
	150	e += sizeof(struct jffs2_acl_entry);
	151	break;
aa98d7cf	152	case ACL_GROUP:
0cfe53d3 EB	153	entry->e_id = cpu_to_je32(
0cfe53d3 EB	154	from_kgid(&init_user_ns, acl_e->e_gid));
de1f72fa	155	e += sizeof(struct jffs2_acl_entry);
aa98d7cf KK	156	break;
	157
	158	case ACL_USER_OBJ:
	159	case ACL_GROUP_OBJ:
	160	case ACL_MASK:
	161	case ACL_OTHER:
de1f72fa	162	e += sizeof(struct jffs2_acl_entry_short);
aa98d7cf KK	163	break;
	164
	165	default:
	166	goto fail;
	167	}
	168	}
dea80134	169	return header;
aa98d7cf	170	fail:
dea80134	171	kfree(header);
aa98d7cf KK	172	return ERR_PTR(-EINVAL);
	173	}
	174
4e34e719	175	struct posix_acl jffs2_get_acl(struct inode inode, int type)
aa98d7cf	176	{
aa98d7cf KK	177	struct posix_acl *acl;
	178	char *value = NULL;
	179	int rc, xprefix;
	180
	181	switch (type) {
	182	case ACL_TYPE_ACCESS:
aa98d7cf KK	183	xprefix = JFFS2_XPREFIX_ACL_ACCESS;
	184	break;
	185	case ACL_TYPE_DEFAULT:
aa98d7cf KK	186	xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
	187	break;
	188	default:
073aaa1b	189	BUG();
aa98d7cf KK	190	}
	191	rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
	192	if (rc > 0) {
	193	value = kmalloc(rc, GFP_KERNEL);
	194	if (!value)
	195	return ERR_PTR(-ENOMEM);
	196	rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
	197	}
	198	if (rc > 0) {
	199	acl = jffs2_acl_from_medium(value, rc);
	200	} else if (rc == -ENODATA \|\| rc == -ENOSYS) {
	201	acl = NULL;
	202	} else {
	203	acl = ERR_PTR(rc);
	204	}
b6861d0a	205	kfree(value);
aa98d7cf KK	206	return acl;
	207	}
	208
cfc8dc6f KK	209	static int __jffs2_set_acl(struct inode inode, int xprefix, struct posix_acl acl)
	210	{
	211	char *value = NULL;
	212	size_t size = 0;
	213	int rc;
	214
	215	if (acl) {
	216	value = jffs2_acl_to_medium(acl, &size);
	217	if (IS_ERR(value))
	218	return PTR_ERR(value);
	219	}
	220	rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
	221	if (!value && rc == -ENODATA)
	222	rc = 0;
	223	kfree(value);
	224
	225	return rc;
	226	}
	227
f2963d45	228	int jffs2_set_acl(struct inode inode, struct posix_acl acl, int type)
aa98d7cf	229	{
aa98d7cf KK	230	int rc, xprefix;
aa98d7cf KK	231
aa98d7cf KK	232	switch (type) {
	233	case ACL_TYPE_ACCESS:
	234	xprefix = JFFS2_XPREFIX_ACL_ACCESS;
	235	if (acl) {
07393101 JK	236	umode_t mode;
	237
	238	rc = posix_acl_update_mode(inode, &mode, &acl);
	239	if (rc)
aa98d7cf KK	240	return rc;
aa98d7cf KK	241	if (inode->i_mode != mode) {
9ed437c5 DW	242	struct iattr attr;
9ed437c5 DW	243
1c24d06f	244	attr.ia_valid = ATTR_MODE \| ATTR_CTIME;
9ed437c5	245	attr.ia_mode = mode;
02027d42	246	attr.ia_ctime = current_time(inode);
9ed437c5 DW	247	rc = jffs2_do_setattr(inode, &attr);
	248	if (rc < 0)
	249	return rc;
aa98d7cf	250	}
aa98d7cf KK	251	}
	252	break;
	253	case ACL_TYPE_DEFAULT:
	254	xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
	255	if (!S_ISDIR(inode->i_mode))
	256	return acl ? -EACCES : 0;
	257	break;
	258	default:
	259	return -EINVAL;
	260	}
cfc8dc6f	261	rc = __jffs2_set_acl(inode, xprefix, acl);
073aaa1b AV	262	if (!rc)
073aaa1b AV	263	set_cached_acl(inode, type, acl);
aa98d7cf KK	264	return rc;
	265	}
	266
d3fb6120	267	int jffs2_init_acl_pre(struct inode dir_i, struct inode inode, umode_t *i_mode)
aa98d7cf	268	{
f2963d45	269	struct posix_acl default_acl, acl;
cfc8dc6f	270	int rc;
aa98d7cf	271
72c04902	272	cache_no_acl(inode);
cfc8dc6f	273
f2963d45 CH	274	rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl);
	275	if (rc)
	276	return rc;
cfc8dc6f	277
f2963d45 CH	278	if (default_acl) {
	279	set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
	280	posix_acl_release(default_acl);
	281	}
	282	if (acl) {
	283	set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
826cae2f	284	posix_acl_release(acl);
aa98d7cf	285	}
cfc8dc6f KK	286	return 0;
	287	}
	288
	289	int jffs2_init_acl_post(struct inode *inode)
	290	{
cfc8dc6f KK	291	int rc;
cfc8dc6f KK	292
290c263b AV	293	if (inode->i_default_acl) {
290c263b AV	294	rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
cfc8dc6f KK	295	if (rc)
	296	return rc;
	297	}
	298
290c263b AV	299	if (inode->i_acl) {
290c263b AV	300	rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
cfc8dc6f KK	301	if (rc)
	302	return rc;
	303	}
	304
8d6ea587	305	return 0;
aa98d7cf	306	}