[linux-block.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 "xfs_error.h"
#include "xfs_acl.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_trans.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(
	struct xfs_mount	*mp,
	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)) {
		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
				len);
		return ERR_PTR(-EFSCORRUPTED);
	}

	count = be32_to_cpu(aclp->acl_cnt);
	if (count > max_entries || XFS_ACL_SIZE(count) != len) {
		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
				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 = make_kuid(&init_user_ns,
						 be32_to_cpu(ace->ae_id));
			break;
		case ACL_GROUP:
			acl_e->e_gid = make_kgid(&init_user_ns,
						 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(
					from_kuid(&init_user_ns, acl_e->e_uid));
			break;
		case ACL_GROUP:
			ace->ae_id = cpu_to_be32(
					from_kgid(&init_user_ns, 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, bool rcu)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	struct posix_acl	*acl = NULL;
	struct xfs_da_args	args = {
		.dp		= ip,
		.attr_filter	= XFS_ATTR_ROOT,
		.valuelen	= XFS_ACL_MAX_SIZE(mp),
	};
	int			error;

	if (rcu)
		return ERR_PTR(-ECHILD);

	trace_xfs_get_acl(ip);

	switch (type) {
	case ACL_TYPE_ACCESS:
		args.name = SGI_ACL_FILE;
		break;
	case ACL_TYPE_DEFAULT:
		args.name = SGI_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	args.namelen = strlen(args.name);

	/*
	 * If the attribute doesn't exist make sure we have a negative cache
	 * entry, for any other error assume it is transient.
	 */
	error = xfs_attr_get(&args);
	if (!error) {
		acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
					XFS_ACL_MAX_ENTRIES(mp));
	} else if (error != -ENOATTR) {
		acl = ERR_PTR(error);
	}

	kmem_free(args.value);
	return acl;
}

int
__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_da_args	args = {
		.dp		= ip,
		.attr_filter	= XFS_ATTR_ROOT,
	};
	int			error;

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

	if (acl) {
		args.valuelen = XFS_ACL_SIZE(acl->a_count);
		args.value = kvzalloc(args.valuelen, GFP_KERNEL);
		if (!args.value)
			return -ENOMEM;
		xfs_acl_to_disk(args.value, acl);
	}

	error = xfs_attr_set(&args);
	kmem_free(args.value);

	/*
	 * If the attribute didn't exist to start with that's fine.
	 */
	if (!acl && error == -ENOATTR)
		error = 0;
	if (!error)
		set_cached_acl(inode, type, acl);
	return error;
}

static int
xfs_acl_set_mode(
	struct inode		*inode,
	umode_t			mode)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	struct xfs_trans	*tp;
	int			error;

	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
	if (error)
		return error;

	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	inode->i_mode = mode;
	inode->i_ctime = current_time(inode);
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

	if (xfs_has_wsync(mp))
		xfs_trans_set_sync(tp);
	return xfs_trans_commit(tp);
}

int
xfs_set_acl(struct user_namespace *mnt_userns, 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(mnt_userns, inode, &mode, &acl);
		if (error)
			return error;
		set_mode = true;
	}

 set_acl:
	/*
	 * 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.
	 */
	error =  __xfs_set_acl(inode, acl, type);
	if (!error && set_mode && mode != inode->i_mode)
		error = xfs_acl_set_mode(inode, mode);
	return error;
}

/*
 * Invalidate any cached ACLs if the user has bypassed the ACL interface.
 * We don't validate the content whatsoever so it is caller responsibility to
 * provide data in valid format and ensure i_mode is consistent.
 */
void
xfs_forget_acl(
	struct inode		*inode,
	const char		*name)
{
	if (!strcmp(name, SGI_ACL_FILE))
		forget_cached_acl(inode, ACL_TYPE_ACCESS);
	else if (!strcmp(name, SGI_ACL_DEFAULT))
		forget_cached_acl(inode, ACL_TYPE_DEFAULT);
}
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"
a5155b87	15	#include "xfs_error.h"
5f213ddb	16	#include "xfs_acl.h"
a2544622 CH	17	#include "xfs_da_format.h"
a2544622 CH	18	#include "xfs_da_btree.h"
5d24ec4c	19	#include "xfs_trans.h"
ef14f0c1	20
5f213ddb	21	#include <linux/posix_acl_xattr.h>
ef14f0c1	22
ef14f0c1 CH	23	/*
	24	* Locking scheme:
	25	* - all ACL updates are protected by inode->i_mutex, which is taken before
	26	* calling into this file.
ef14f0c1 CH	27	*/
	28
	29	STATIC struct posix_acl *
0a8aa193	30	xfs_acl_from_disk(
a5155b87	31	struct xfs_mount *mp,
86a21c79 AG	32	const struct xfs_acl *aclp,
	33	int len,
	34	int max_entries)
ef14f0c1 CH	35	{
	36	struct posix_acl_entry *acl_e;
	37	struct posix_acl *acl;
86a21c79	38	const struct xfs_acl_entry *ace;
093019cf	39	unsigned int count, i;
ef14f0c1	40
a5155b87 DW	41	if (len < sizeof(*aclp)) {
	42	XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
	43	len);
86a21c79	44	return ERR_PTR(-EFSCORRUPTED);
a5155b87 DW	45	}
a5155b87 DW	46
ef14f0c1	47	count = be32_to_cpu(aclp->acl_cnt);
a5155b87 DW	48	if (count > max_entries \|\| XFS_ACL_SIZE(count) != len) {
	49	XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
	50	len);
fa8b18ed	51	return ERR_PTR(-EFSCORRUPTED);
a5155b87	52	}
ef14f0c1 CH	53
	54	acl = posix_acl_alloc(count, GFP_KERNEL);
	55	if (!acl)
	56	return ERR_PTR(-ENOMEM);
	57
	58	for (i = 0; i < count; i++) {
	59	acl_e = &acl->a_entries[i];
	60	ace = &aclp->acl_entry[i];
	61
	62	/*
	63	* The tag is 32 bits on disk and 16 bits in core.
	64	*
	65	* Because every access to it goes through the core
	66	* format first this is not a problem.
	67	*/
	68	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	69	acl_e->e_perm = be16_to_cpu(ace->ae_perm);
	70
	71	switch (acl_e->e_tag) {
	72	case ACL_USER:
ba8adad5 CH	73	acl_e->e_uid = make_kuid(&init_user_ns,
ba8adad5 CH	74	be32_to_cpu(ace->ae_id));
288bbe0e	75	break;
ef14f0c1	76	case ACL_GROUP:
ba8adad5 CH	77	acl_e->e_gid = make_kgid(&init_user_ns,
ba8adad5 CH	78	be32_to_cpu(ace->ae_id));
ef14f0c1 CH	79	break;
	80	case ACL_USER_OBJ:
	81	case ACL_GROUP_OBJ:
	82	case ACL_MASK:
	83	case ACL_OTHER:
ef14f0c1 CH	84	break;
	85	default:
	86	goto fail;
	87	}
	88	}
	89	return acl;
	90
	91	fail:
	92	posix_acl_release(acl);
	93	return ERR_PTR(-EINVAL);
	94	}
	95
	96	STATIC void
	97	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	98	{
	99	const struct posix_acl_entry *acl_e;
	100	struct xfs_acl_entry *ace;
	101	int i;
	102
	103	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	104	for (i = 0; i < acl->a_count; i++) {
	105	ace = &aclp->acl_entry[i];
	106	acl_e = &acl->a_entries[i];
	107
	108	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
288bbe0e DE	109	switch (acl_e->e_tag) {
288bbe0e DE	110	case ACL_USER:
ba8adad5 CH	111	ace->ae_id = cpu_to_be32(
ba8adad5 CH	112	from_kuid(&init_user_ns, acl_e->e_uid));
288bbe0e DE	113	break;
288bbe0e DE	114	case ACL_GROUP:
ba8adad5 CH	115	ace->ae_id = cpu_to_be32(
ba8adad5 CH	116	from_kgid(&init_user_ns, acl_e->e_gid));
288bbe0e DE	117	break;
	118	default:
	119	ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
	120	break;
	121	}
	122
ef14f0c1 CH	123	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	124	}
	125	}
	126
ef14f0c1	127	struct posix_acl *
0cad6246	128	xfs_get_acl(struct inode *inode, int type, bool rcu)
ef14f0c1	129	{
e5171d7e CH	130	struct xfs_inode *ip = XFS_I(inode);
	131	struct xfs_mount *mp = ip->i_mount;
	132	struct posix_acl *acl = NULL;
	133	struct xfs_da_args args = {
	134	.dp = ip,
d5f0f49a	135	.attr_filter = XFS_ATTR_ROOT,
e5171d7e CH	136	.valuelen = XFS_ACL_MAX_SIZE(mp),
	137	};
	138	int error;
ef14f0c1	139
0cad6246 MS	140	if (rcu)
	141	return ERR_PTR(-ECHILD);
	142
4e34e719 CH	143	trace_xfs_get_acl(ip);
4e34e719 CH	144
ef14f0c1 CH	145	switch (type) {
ef14f0c1 CH	146	case ACL_TYPE_ACCESS:
e5171d7e	147	args.name = SGI_ACL_FILE;
ef14f0c1 CH	148	break;
ef14f0c1 CH	149	case ACL_TYPE_DEFAULT:
e5171d7e	150	args.name = SGI_ACL_DEFAULT;
ef14f0c1 CH	151	break;
ef14f0c1 CH	152	default:
1cbd20d8	153	BUG();
ef14f0c1	154	}
e5171d7e	155	args.namelen = strlen(args.name);
ef14f0c1	156
d49db18b CH	157	/*
	158	* If the attribute doesn't exist make sure we have a negative cache
	159	* entry, for any other error assume it is transient.
	160	*/
e5171d7e	161	error = xfs_attr_get(&args);
d49db18b	162	if (!error) {
e5171d7e CH	163	acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
e5171d7e CH	164	XFS_ACL_MAX_ENTRIES(mp));
d49db18b CH	165	} else if (error != -ENOATTR) {
d49db18b CH	166	acl = ERR_PTR(error);
ef14f0c1	167	}
d49db18b CH	168
d49db18b CH	169	kmem_free(args.value);
ef14f0c1 CH	170	return acl;
	171	}
	172
8ba35875 JK	173	int
8ba35875 JK	174	__xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
ef14f0c1	175	{
a2544622 CH	176	struct xfs_inode *ip = XFS_I(inode);
	177	struct xfs_da_args args = {
	178	.dp = ip,
d5f0f49a	179	.attr_filter = XFS_ATTR_ROOT,
a2544622 CH	180	};
a2544622 CH	181	int error;
ef14f0c1	182
ef14f0c1 CH	183	switch (type) {
ef14f0c1 CH	184	case ACL_TYPE_ACCESS:
a2544622	185	args.name = SGI_ACL_FILE;
ef14f0c1 CH	186	break;
	187	case ACL_TYPE_DEFAULT:
	188	if (!S_ISDIR(inode->i_mode))
	189	return acl ? -EACCES : 0;
a2544622	190	args.name = SGI_ACL_DEFAULT;
ef14f0c1 CH	191	break;
	192	default:
	193	return -EINVAL;
	194	}
a2544622	195	args.namelen = strlen(args.name);
ef14f0c1 CH	196
ef14f0c1 CH	197	if (acl) {
ed02d13f	198	args.valuelen = XFS_ACL_SIZE(acl->a_count);
8ca79df8	199	args.value = kvzalloc(args.valuelen, GFP_KERNEL);
a2544622	200	if (!args.value)
fdd3ccee	201	return -ENOMEM;
a2544622	202	xfs_acl_to_disk(args.value, acl);
ef14f0c1 CH	203	}
ef14f0c1 CH	204
a2544622 CH	205	error = xfs_attr_set(&args);
a2544622 CH	206	kmem_free(args.value);
0eb81a5f CH	207
	208	/*
	209	* If the attribute didn't exist to start with that's fine.
	210	*/
	211	if (!acl && error == -ENOATTR)
	212	error = 0;
ef14f0c1	213	if (!error)
1cbd20d8	214	set_cached_acl(inode, type, acl);
ef14f0c1 CH	215	return error;
	216	}
	217
ef14f0c1	218	static int
5d24ec4c CH	219	xfs_acl_set_mode(
	220	struct inode *inode,
	221	umode_t mode)
ef14f0c1	222	{
5d24ec4c CH	223	struct xfs_inode *ip = XFS_I(inode);
	224	struct xfs_mount *mp = ip->i_mount;
	225	struct xfs_trans *tp;
	226	int error;
ef14f0c1	227
5d24ec4c CH	228	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
	229	if (error)
	230	return error;
ef14f0c1	231
5d24ec4c CH	232	xfs_ilock(ip, XFS_ILOCK_EXCL);
	233	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	234	inode->i_mode = mode;
	235	inode->i_ctime = current_time(inode);
	236	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
ef14f0c1	237
0560f31a	238	if (xfs_has_wsync(mp))
5d24ec4c CH	239	xfs_trans_set_sync(tp);
5d24ec4c CH	240	return xfs_trans_commit(tp);
ef14f0c1 CH	241	}
ef14f0c1 CH	242
ef14f0c1	243	int
549c7297 CB	244	xfs_set_acl(struct user_namespace mnt_userns, struct inode inode,
549c7297 CB	245	struct posix_acl *acl, int type)
ef14f0c1	246	{
67f2ffe3 DC	247	umode_t mode;
67f2ffe3 DC	248	bool set_mode = false;
431547b3	249	int error = 0;
ef14f0c1	250
2401dc29	251	if (!acl)
ef14f0c1 CH	252	goto set_acl;
ef14f0c1 CH	253
4ae69fea	254	error = -E2BIG;
0a8aa193	255	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
2401dc29	256	return error;
ef14f0c1 CH	257
ef14f0c1 CH	258	if (type == ACL_TYPE_ACCESS) {
f736d93d	259	error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl);
07393101 JK	260	if (error)
07393101 JK	261	return error;
67f2ffe3	262	set_mode = true;
ef14f0c1 CH	263	}
	264
	265	set_acl:
67f2ffe3 DC	266	/*
	267	* We set the mode after successfully updating the ACL xattr because the
	268	* xattr update can fail at ENOSPC and we don't want to change the mode
	269	* if the ACL update hasn't been applied.
	270	*/
5d24ec4c CH	271	error = __xfs_set_acl(inode, acl, type);
	272	if (!error && set_mode && mode != inode->i_mode)
	273	error = xfs_acl_set_mode(inode, mode);
67f2ffe3	274	return error;
ef14f0c1	275	}
5a3930e2 CH	276
	277	/*
	278	* Invalidate any cached ACLs if the user has bypassed the ACL interface.
	279	* We don't validate the content whatsoever so it is caller responsibility to
	280	* provide data in valid format and ensure i_mode is consistent.
	281	*/
	282	void
	283	xfs_forget_acl(
	284	struct inode *inode,
	285	const char *name)
	286	{
	287	if (!strcmp(name, SGI_ACL_FILE))
	288	forget_cached_acl(inode, ACL_TYPE_ACCESS);
	289	else if (!strcmp(name, SGI_ACL_DEFAULT))
	290	forget_cached_acl(inode, ACL_TYPE_DEFAULT);
	291	}