[mirror_ubuntu-eoan-kernel.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_shared.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_attr.h"
#include "xfs_trace.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"
5467b34b	7	#include "xfs_shared.h"
a4fbe6ab	8	#include "xfs_format.h"
69432832	9	#include "xfs_log_format.h"
7fd36c44	10	#include "xfs_trans_resv.h"
0a8aa193	11	#include "xfs_mount.h"
a4fbe6ab	12	#include "xfs_inode.h"
a4fbe6ab	13	#include "xfs_attr.h"
0b1b213f	14	#include "xfs_trace.h"
ef14f0c1 CH	15	#include <linux/posix_acl_xattr.h>
	16
	17
ef14f0c1 CH	18	/*
	19	* Locking scheme:
	20	* - all ACL updates are protected by inode->i_mutex, which is taken before
	21	* calling into this file.
ef14f0c1 CH	22	*/
	23
	24	STATIC struct posix_acl *
0a8aa193	25	xfs_acl_from_disk(
86a21c79 AG	26	const struct xfs_acl *aclp,
	27	int len,
	28	int max_entries)
ef14f0c1 CH	29	{
	30	struct posix_acl_entry *acl_e;
	31	struct posix_acl *acl;
86a21c79	32	const struct xfs_acl_entry *ace;
093019cf	33	unsigned int count, i;
ef14f0c1	34
86a21c79 AG	35	if (len < sizeof(*aclp))
86a21c79 AG	36	return ERR_PTR(-EFSCORRUPTED);
ef14f0c1	37	count = be32_to_cpu(aclp->acl_cnt);
86a21c79	38	if (count > max_entries \|\| XFS_ACL_SIZE(count) != len)
fa8b18ed	39	return ERR_PTR(-EFSCORRUPTED);
ef14f0c1 CH	40
	41	acl = posix_acl_alloc(count, GFP_KERNEL);
	42	if (!acl)
	43	return ERR_PTR(-ENOMEM);
	44
	45	for (i = 0; i < count; i++) {
	46	acl_e = &acl->a_entries[i];
	47	ace = &aclp->acl_entry[i];
	48
	49	/*
	50	* The tag is 32 bits on disk and 16 bits in core.
	51	*
	52	* Because every access to it goes through the core
	53	* format first this is not a problem.
	54	*/
	55	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	56	acl_e->e_perm = be16_to_cpu(ace->ae_perm);
	57
	58	switch (acl_e->e_tag) {
	59	case ACL_USER:
288bbe0e DE	60	acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
288bbe0e DE	61	break;
ef14f0c1	62	case ACL_GROUP:
288bbe0e	63	acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
ef14f0c1 CH	64	break;
	65	case ACL_USER_OBJ:
	66	case ACL_GROUP_OBJ:
	67	case ACL_MASK:
	68	case ACL_OTHER:
ef14f0c1 CH	69	break;
	70	default:
	71	goto fail;
	72	}
	73	}
	74	return acl;
	75
	76	fail:
	77	posix_acl_release(acl);
	78	return ERR_PTR(-EINVAL);
	79	}
	80
	81	STATIC void
	82	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	83	{
	84	const struct posix_acl_entry *acl_e;
	85	struct xfs_acl_entry *ace;
	86	int i;
	87
	88	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	89	for (i = 0; i < acl->a_count; i++) {
	90	ace = &aclp->acl_entry[i];
	91	acl_e = &acl->a_entries[i];
	92
	93	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
288bbe0e DE	94	switch (acl_e->e_tag) {
	95	case ACL_USER:
	96	ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
	97	break;
	98	case ACL_GROUP:
	99	ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
	100	break;
	101	default:
	102	ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
	103	break;
	104	}
	105
ef14f0c1 CH	106	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	107	}
	108	}
	109
ef14f0c1 CH	110	struct posix_acl *
	111	xfs_get_acl(struct inode *inode, int type)
	112	{
	113	struct xfs_inode *ip = XFS_I(inode);
2401dc29	114	struct posix_acl *acl = NULL;
ef14f0c1	115	struct xfs_acl *xfs_acl;
a9273ca5	116	unsigned char *ea_name;
ef14f0c1	117	int error;
0a8aa193	118	int len;
ef14f0c1	119
4e34e719 CH	120	trace_xfs_get_acl(ip);
4e34e719 CH	121
ef14f0c1 CH	122	switch (type) {
	123	case ACL_TYPE_ACCESS:
	124	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	125	break;
	126	case ACL_TYPE_DEFAULT:
	127	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	128	break;
ef14f0c1 CH	129	default:
1cbd20d8	130	BUG();
ef14f0c1 CH	131	}
ef14f0c1 CH	132
ef14f0c1 CH	133	/*
	134	* If we have a cached ACLs value just return it, not need to
	135	* go out to the disk.
	136	*/
0a8aa193	137	len = XFS_ACL_MAX_SIZE(ip->i_mount);
fdd3ccee DC	138	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	139	if (!xfs_acl)
	140	return ERR_PTR(-ENOMEM);
ef14f0c1	141
2451337d	142	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
a9273ca5	143	&len, ATTR_ROOT);
ef14f0c1 CH	144	if (error) {
	145	/*
	146	* If the attribute doesn't exist make sure we have a negative
b8a7a3a6	147	* cache entry, for any other error assume it is transient.
ef14f0c1	148	*/
b8a7a3a6 AG	149	if (error != -ENOATTR)
	150	acl = ERR_PTR(error);
	151	} else {
	152	acl = xfs_acl_from_disk(xfs_acl, len,
	153	XFS_ACL_MAX_ENTRIES(ip->i_mount));
ef14f0c1	154	}
fdd3ccee	155	kmem_free(xfs_acl);
ef14f0c1 CH	156	return acl;
	157	}
	158
8ba35875 JK	159	int
8ba35875 JK	160	__xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
ef14f0c1 CH	161	{
ef14f0c1 CH	162	struct xfs_inode *ip = XFS_I(inode);
a9273ca5	163	unsigned char *ea_name;
ef14f0c1 CH	164	int error;
ef14f0c1 CH	165
ef14f0c1 CH	166	switch (type) {
	167	case ACL_TYPE_ACCESS:
	168	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	169	break;
	170	case ACL_TYPE_DEFAULT:
	171	if (!S_ISDIR(inode->i_mode))
	172	return acl ? -EACCES : 0;
	173	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	174	break;
	175	default:
	176	return -EINVAL;
	177	}
	178
	179	if (acl) {
	180	struct xfs_acl *xfs_acl;
0a8aa193	181	int len = XFS_ACL_MAX_SIZE(ip->i_mount);
ef14f0c1	182
fdd3ccee DC	183	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	184	if (!xfs_acl)
	185	return -ENOMEM;
ef14f0c1 CH	186
ef14f0c1 CH	187	xfs_acl_to_disk(xfs_acl, acl);
0a8aa193 DC	188
	189	/* subtract away the unused acl entries */
	190	len -= sizeof(struct xfs_acl_entry) *
	191	(XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
ef14f0c1	192
2451337d	193	error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
ef14f0c1 CH	194	len, ATTR_ROOT);
ef14f0c1 CH	195
fdd3ccee	196	kmem_free(xfs_acl);
ef14f0c1 CH	197	} else {
	198	/*
	199	* A NULL ACL argument means we want to remove the ACL.
	200	*/
2451337d	201	error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);
ef14f0c1 CH	202
	203	/*
	204	* If the attribute didn't exist to start with that's fine.
	205	*/
	206	if (error == -ENOATTR)
	207	error = 0;
	208	}
	209
	210	if (!error)
1cbd20d8	211	set_cached_acl(inode, type, acl);
ef14f0c1 CH	212	return error;
	213	}
	214
ef14f0c1	215	static int
d3fb6120	216	xfs_set_mode(struct inode *inode, umode_t mode)
ef14f0c1 CH	217	{
	218	int error = 0;
	219
	220	if (mode != inode->i_mode) {
	221	struct iattr iattr;
	222
d6d59bad	223	iattr.ia_valid = ATTR_MODE \| ATTR_CTIME;
ef14f0c1	224	iattr.ia_mode = mode;
c2050a45	225	iattr.ia_ctime = current_time(inode);
ef14f0c1	226
2451337d	227	error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
ef14f0c1 CH	228	}
	229
	230	return error;
	231	}
	232
ef14f0c1	233	int
2401dc29	234	xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
ef14f0c1	235	{
67f2ffe3 DC	236	umode_t mode;
67f2ffe3 DC	237	bool set_mode = false;
431547b3	238	int error = 0;
ef14f0c1	239
2401dc29	240	if (!acl)
ef14f0c1 CH	241	goto set_acl;
ef14f0c1 CH	242
4ae69fea	243	error = -E2BIG;
0a8aa193	244	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
2401dc29	245	return error;
ef14f0c1 CH	246
ef14f0c1 CH	247	if (type == ACL_TYPE_ACCESS) {
07393101 JK	248	error = posix_acl_update_mode(inode, &mode, &acl);
	249	if (error)
	250	return error;
67f2ffe3	251	set_mode = true;
ef14f0c1 CH	252	}
	253
	254	set_acl:
67f2ffe3 DC	255	error = __xfs_set_acl(inode, acl, type);
	256	if (error)
	257	return error;
	258
	259	/*
	260	* We set the mode after successfully updating the ACL xattr because the
	261	* xattr update can fail at ENOSPC and we don't want to change the mode
	262	* if the ACL update hasn't been applied.
	263	*/
	264	if (set_mode)
	265	error = xfs_set_mode(inode, mode);
	266
	267	return error;
ef14f0c1	268	}