[linux.git] / fs / xfs / xfs_acl.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2008, Christoph Hellwig
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_acl.h"
#include "xfs_attr.h"
#include "xfs_trace.h"
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>


/*
 * Locking scheme:
 *  - all ACL updates are protected by inode->i_mutex, which is taken before
 *    calling into this file.
 */

STATIC struct posix_acl *
xfs_acl_from_disk(
	const struct xfs_acl	*aclp,
	int			len,
	int			max_entries)
{
	struct posix_acl_entry *acl_e;
	struct posix_acl *acl;
	const struct xfs_acl_entry *ace;
	unsigned int count, i;

	if (len < sizeof(*aclp))
		return ERR_PTR(-EFSCORRUPTED);
	count = be32_to_cpu(aclp->acl_cnt);
	if (count > max_entries || XFS_ACL_SIZE(count) != len)
		return ERR_PTR(-EFSCORRUPTED);

	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);

	for (i = 0; i < count; i++) {
		acl_e = &acl->a_entries[i];
		ace = &aclp->acl_entry[i];

		/*
		 * The tag is 32 bits on disk and 16 bits in core.
		 *
		 * Because every access to it goes through the core
		 * format first this is not a problem.
		 */
		acl_e->e_tag = be32_to_cpu(ace->ae_tag);
		acl_e->e_perm = be16_to_cpu(ace->ae_perm);

		switch (acl_e->e_tag) {
		case ACL_USER:
			acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
			break;
		case ACL_GROUP:
			acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
			break;
		case ACL_USER_OBJ:
		case ACL_GROUP_OBJ:
		case ACL_MASK:
		case ACL_OTHER:
			break;
		default:
			goto fail;
		}
	}
	return acl;

fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
}

STATIC void
xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
{
	const struct posix_acl_entry *acl_e;
	struct xfs_acl_entry *ace;
	int i;

	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	for (i = 0; i < acl->a_count; i++) {
		ace = &aclp->acl_entry[i];
		acl_e = &acl->a_entries[i];

		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
		switch (acl_e->e_tag) {
		case ACL_USER:
			ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
			break;
		case ACL_GROUP:
			ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
			break;
		default:
			ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
			break;
		}

		ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	}
}

struct posix_acl *
xfs_get_acl(struct inode *inode, int type)
{
	struct xfs_inode *ip = XFS_I(inode);
	struct posix_acl *acl = NULL;
	struct xfs_acl *xfs_acl;
	unsigned char *ea_name;
	int error;
	int len;

	trace_xfs_get_acl(ip);

	switch (type) {
	case ACL_TYPE_ACCESS:
		ea_name = SGI_ACL_FILE;
		break;
	case ACL_TYPE_DEFAULT:
		ea_name = SGI_ACL_DEFAULT;
		break;
	default:
		BUG();
	}

	/*
	 * If we have a cached ACLs value just return it, not need to
	 * go out to the disk.
	 */
	len = XFS_ACL_MAX_SIZE(ip->i_mount);
	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	if (!xfs_acl)
		return ERR_PTR(-ENOMEM);

	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
							&len, ATTR_ROOT);
	if (error) {
		/*
		 * If the attribute doesn't exist make sure we have a negative
		 * cache entry, for any other error assume it is transient.
		 */
		if (error != -ENOATTR)
			acl = ERR_PTR(error);
	} else  {
		acl = xfs_acl_from_disk(xfs_acl, len,
					XFS_ACL_MAX_ENTRIES(ip->i_mount));
	}
	kmem_free(xfs_acl);
	return acl;
}

int
__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	struct xfs_inode *ip = XFS_I(inode);
	unsigned char *ea_name;
	int error;

	switch (type) {
	case ACL_TYPE_ACCESS:
		ea_name = SGI_ACL_FILE;
		break;
	case ACL_TYPE_DEFAULT:
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EACCES : 0;
		ea_name = SGI_ACL_DEFAULT;
		break;
	default:
		return -EINVAL;
	}

	if (acl) {
		struct xfs_acl *xfs_acl;
		int len = XFS_ACL_MAX_SIZE(ip->i_mount);

		xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
		if (!xfs_acl)
			return -ENOMEM;

		xfs_acl_to_disk(xfs_acl, acl);

		/* subtract away the unused acl entries */
		len -= sizeof(struct xfs_acl_entry) *
			 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);

		error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
				len, ATTR_ROOT);

		kmem_free(xfs_acl);
	} else {
		/*
		 * A NULL ACL argument means we want to remove the ACL.
		 */
		error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);

		/*
		 * If the attribute didn't exist to start with that's fine.
		 */
		if (error == -ENOATTR)
			error = 0;
	}

	if (!error)
		set_cached_acl(inode, type, acl);
	return error;
}

static int
xfs_set_mode(struct inode *inode, umode_t mode)
{
	int error = 0;

	if (mode != inode->i_mode) {
		struct iattr iattr;

		iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
		iattr.ia_mode = mode;
		iattr.ia_ctime = current_time(inode);

		error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
	}

	return error;
}

int
xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	umode_t mode;
	bool set_mode = false;
	int error = 0;

	if (!acl)
		goto set_acl;

	error = -E2BIG;
	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
		return error;

	if (type == ACL_TYPE_ACCESS) {
		error = posix_acl_update_mode(inode, &mode, &acl);
		if (error)
			return error;
		set_mode = true;
	}

 set_acl:
	error =  __xfs_set_acl(inode, acl, type);
	if (error)
		return error;

	/*
	 * We set the mode after successfully updating the ACL xattr because the
	 * xattr update can fail at ENOSPC and we don't want to change the mode
	 * if the ACL update hasn't been applied.
	 */
	if (set_mode)
		error = xfs_set_mode(inode, mode);

	return error;
}
Commit	Line	Data
0b61f8a4	1	// SPDX-License-Identifier: GPL-2.0
ef14f0c1 CH	2	/*
	3	* Copyright (c) 2008, Christoph Hellwig
	4	* All Rights Reserved.
ef14f0c1 CH	5	*/
ef14f0c1 CH	6	#include "xfs.h"
a4fbe6ab	7	#include "xfs_format.h"
69432832	8	#include "xfs_log_format.h"
7fd36c44	9	#include "xfs_trans_resv.h"
0a8aa193	10	#include "xfs_mount.h"
a4fbe6ab DC	11	#include "xfs_inode.h"
	12	#include "xfs_acl.h"
	13	#include "xfs_attr.h"
0b1b213f	14	#include "xfs_trace.h"
5a0e3ad6	15	#include <linux/slab.h>
ef14f0c1 CH	16	#include <linux/xattr.h>
	17	#include <linux/posix_acl_xattr.h>
	18
	19
ef14f0c1 CH	20	/*
	21	* Locking scheme:
	22	* - all ACL updates are protected by inode->i_mutex, which is taken before
	23	* calling into this file.
ef14f0c1 CH	24	*/
	25
	26	STATIC struct posix_acl *
0a8aa193	27	xfs_acl_from_disk(
86a21c79 AG	28	const struct xfs_acl *aclp,
	29	int len,
	30	int max_entries)
ef14f0c1 CH	31	{
	32	struct posix_acl_entry *acl_e;
	33	struct posix_acl *acl;
86a21c79	34	const struct xfs_acl_entry *ace;
093019cf	35	unsigned int count, i;
ef14f0c1	36
86a21c79 AG	37	if (len < sizeof(*aclp))
86a21c79 AG	38	return ERR_PTR(-EFSCORRUPTED);
ef14f0c1	39	count = be32_to_cpu(aclp->acl_cnt);
86a21c79	40	if (count > max_entries \|\| XFS_ACL_SIZE(count) != len)
fa8b18ed	41	return ERR_PTR(-EFSCORRUPTED);
ef14f0c1 CH	42
	43	acl = posix_acl_alloc(count, GFP_KERNEL);
	44	if (!acl)
	45	return ERR_PTR(-ENOMEM);
	46
	47	for (i = 0; i < count; i++) {
	48	acl_e = &acl->a_entries[i];
	49	ace = &aclp->acl_entry[i];
	50
	51	/*
	52	* The tag is 32 bits on disk and 16 bits in core.
	53	*
	54	* Because every access to it goes through the core
	55	* format first this is not a problem.
	56	*/
	57	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	58	acl_e->e_perm = be16_to_cpu(ace->ae_perm);
	59
	60	switch (acl_e->e_tag) {
	61	case ACL_USER:
288bbe0e DE	62	acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
288bbe0e DE	63	break;
ef14f0c1	64	case ACL_GROUP:
288bbe0e	65	acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
ef14f0c1 CH	66	break;
	67	case ACL_USER_OBJ:
	68	case ACL_GROUP_OBJ:
	69	case ACL_MASK:
	70	case ACL_OTHER:
ef14f0c1 CH	71	break;
	72	default:
	73	goto fail;
	74	}
	75	}
	76	return acl;
	77
	78	fail:
	79	posix_acl_release(acl);
	80	return ERR_PTR(-EINVAL);
	81	}
	82
	83	STATIC void
	84	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	85	{
	86	const struct posix_acl_entry *acl_e;
	87	struct xfs_acl_entry *ace;
	88	int i;
	89
	90	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	91	for (i = 0; i < acl->a_count; i++) {
	92	ace = &aclp->acl_entry[i];
	93	acl_e = &acl->a_entries[i];
	94
	95	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
288bbe0e DE	96	switch (acl_e->e_tag) {
	97	case ACL_USER:
	98	ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
	99	break;
	100	case ACL_GROUP:
	101	ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
	102	break;
	103	default:
	104	ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
	105	break;
	106	}
	107
ef14f0c1 CH	108	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	109	}
	110	}
	111
ef14f0c1 CH	112	struct posix_acl *
	113	xfs_get_acl(struct inode *inode, int type)
	114	{
	115	struct xfs_inode *ip = XFS_I(inode);
2401dc29	116	struct posix_acl *acl = NULL;
ef14f0c1	117	struct xfs_acl *xfs_acl;
a9273ca5	118	unsigned char *ea_name;
ef14f0c1	119	int error;
0a8aa193	120	int len;
ef14f0c1	121
4e34e719 CH	122	trace_xfs_get_acl(ip);
4e34e719 CH	123
ef14f0c1 CH	124	switch (type) {
	125	case ACL_TYPE_ACCESS:
	126	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	127	break;
	128	case ACL_TYPE_DEFAULT:
	129	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	130	break;
ef14f0c1 CH	131	default:
1cbd20d8	132	BUG();
ef14f0c1 CH	133	}
ef14f0c1 CH	134
ef14f0c1 CH	135	/*
	136	* If we have a cached ACLs value just return it, not need to
	137	* go out to the disk.
	138	*/
0a8aa193	139	len = XFS_ACL_MAX_SIZE(ip->i_mount);
fdd3ccee DC	140	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	141	if (!xfs_acl)
	142	return ERR_PTR(-ENOMEM);
ef14f0c1	143
2451337d	144	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
a9273ca5	145	&len, ATTR_ROOT);
ef14f0c1 CH	146	if (error) {
	147	/*
	148	* If the attribute doesn't exist make sure we have a negative
b8a7a3a6	149	* cache entry, for any other error assume it is transient.
ef14f0c1	150	*/
b8a7a3a6 AG	151	if (error != -ENOATTR)
	152	acl = ERR_PTR(error);
	153	} else {
	154	acl = xfs_acl_from_disk(xfs_acl, len,
	155	XFS_ACL_MAX_ENTRIES(ip->i_mount));
ef14f0c1	156	}
fdd3ccee	157	kmem_free(xfs_acl);
ef14f0c1 CH	158	return acl;
	159	}
	160
8ba35875 JK	161	int
8ba35875 JK	162	__xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
ef14f0c1 CH	163	{
ef14f0c1 CH	164	struct xfs_inode *ip = XFS_I(inode);
a9273ca5	165	unsigned char *ea_name;
ef14f0c1 CH	166	int error;
ef14f0c1 CH	167
ef14f0c1 CH	168	switch (type) {
	169	case ACL_TYPE_ACCESS:
	170	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	171	break;
	172	case ACL_TYPE_DEFAULT:
	173	if (!S_ISDIR(inode->i_mode))
	174	return acl ? -EACCES : 0;
	175	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	176	break;
	177	default:
	178	return -EINVAL;
	179	}
	180
	181	if (acl) {
	182	struct xfs_acl *xfs_acl;
0a8aa193	183	int len = XFS_ACL_MAX_SIZE(ip->i_mount);
ef14f0c1	184
fdd3ccee DC	185	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	186	if (!xfs_acl)
	187	return -ENOMEM;
ef14f0c1 CH	188
ef14f0c1 CH	189	xfs_acl_to_disk(xfs_acl, acl);
0a8aa193 DC	190
	191	/* subtract away the unused acl entries */
	192	len -= sizeof(struct xfs_acl_entry) *
	193	(XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
ef14f0c1	194
2451337d	195	error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
ef14f0c1 CH	196	len, ATTR_ROOT);
ef14f0c1 CH	197
fdd3ccee	198	kmem_free(xfs_acl);
ef14f0c1 CH	199	} else {
	200	/*
	201	* A NULL ACL argument means we want to remove the ACL.
	202	*/
2451337d	203	error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);
ef14f0c1 CH	204
	205	/*
	206	* If the attribute didn't exist to start with that's fine.
	207	*/
	208	if (error == -ENOATTR)
	209	error = 0;
	210	}
	211
	212	if (!error)
1cbd20d8	213	set_cached_acl(inode, type, acl);
ef14f0c1 CH	214	return error;
	215	}
	216
ef14f0c1	217	static int
d3fb6120	218	xfs_set_mode(struct inode *inode, umode_t mode)
ef14f0c1 CH	219	{
	220	int error = 0;
	221
	222	if (mode != inode->i_mode) {
	223	struct iattr iattr;
	224
d6d59bad	225	iattr.ia_valid = ATTR_MODE \| ATTR_CTIME;
ef14f0c1	226	iattr.ia_mode = mode;
c2050a45	227	iattr.ia_ctime = current_time(inode);
ef14f0c1	228
2451337d	229	error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
ef14f0c1 CH	230	}
	231
	232	return error;
	233	}
	234
ef14f0c1	235	int
2401dc29	236	xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
ef14f0c1	237	{
67f2ffe3 DC	238	umode_t mode;
67f2ffe3 DC	239	bool set_mode = false;
431547b3	240	int error = 0;
ef14f0c1	241
2401dc29	242	if (!acl)
ef14f0c1 CH	243	goto set_acl;
ef14f0c1 CH	244
4ae69fea	245	error = -E2BIG;
0a8aa193	246	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
2401dc29	247	return error;
ef14f0c1 CH	248
ef14f0c1 CH	249	if (type == ACL_TYPE_ACCESS) {
07393101 JK	250	error = posix_acl_update_mode(inode, &mode, &acl);
	251	if (error)
	252	return error;
67f2ffe3	253	set_mode = true;
ef14f0c1 CH	254	}
	255
	256	set_acl:
67f2ffe3 DC	257	error = __xfs_set_acl(inode, acl, type);
	258	if (error)
	259	return error;
	260
	261	/*
	262	* We set the mode after successfully updating the ACL xattr because the
	263	* xattr update can fail at ENOSPC and we don't want to change the mode
	264	* if the ACL update hasn't been applied.
	265	*/
	266	if (set_mode)
	267	error = xfs_set_mode(inode, mode);
	268
	269	return error;
ef14f0c1	270	}