[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_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_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_trace.h"
#include "xfs_error.h"
#include "xfs_acl.h"
#include "xfs_trans.h"
#include "xfs_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(
	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);
	}

	kvfree(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_change(&args, XFS_ATTRUPDATE_UPSERT);
		kvfree(args.value);
	} else {
		error = xfs_attr_change(&args, XFS_ATTRUPDATE_REMOVE);
		/*
		 * 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_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_set_ctime_current(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 mnt_idmap *idmap, struct dentry *dentry,
	    struct posix_acl *acl, int type)
{
	umode_t mode;
	bool set_mode = false;
	int error = 0;
	struct inode *inode = d_inode(dentry);

	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(idmap, 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"
e0c41089 DC	13	#include "xfs_da_format.h"
e0c41089 DC	14	#include "xfs_da_btree.h"
a4fbe6ab	15	#include "xfs_attr.h"
0b1b213f	16	#include "xfs_trace.h"
a5155b87	17	#include "xfs_error.h"
5f213ddb	18	#include "xfs_acl.h"
5d24ec4c	19	#include "xfs_trans.h"
efc2efeb	20	#include "xfs_xattr.h"
ef14f0c1	21
5f213ddb	22	#include <linux/posix_acl_xattr.h>
ef14f0c1	23
ef14f0c1 CH	24	/*
	25	* Locking scheme:
	26	* - all ACL updates are protected by inode->i_mutex, which is taken before
	27	* calling into this file.
ef14f0c1 CH	28	*/
	29
	30	STATIC struct posix_acl *
0a8aa193	31	xfs_acl_from_disk(
a5155b87	32	struct xfs_mount *mp,
86a21c79 AG	33	const struct xfs_acl *aclp,
	34	int len,
	35	int max_entries)
ef14f0c1 CH	36	{
	37	struct posix_acl_entry *acl_e;
	38	struct posix_acl *acl;
86a21c79	39	const struct xfs_acl_entry *ace;
093019cf	40	unsigned int count, i;
ef14f0c1	41
a5155b87 DW	42	if (len < sizeof(*aclp)) {
	43	XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
	44	len);
86a21c79	45	return ERR_PTR(-EFSCORRUPTED);
a5155b87 DW	46	}
a5155b87 DW	47
ef14f0c1	48	count = be32_to_cpu(aclp->acl_cnt);
a5155b87 DW	49	if (count > max_entries \|\| XFS_ACL_SIZE(count) != len) {
	50	XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
	51	len);
fa8b18ed	52	return ERR_PTR(-EFSCORRUPTED);
a5155b87	53	}
ef14f0c1 CH	54
	55	acl = posix_acl_alloc(count, GFP_KERNEL);
	56	if (!acl)
	57	return ERR_PTR(-ENOMEM);
	58
	59	for (i = 0; i < count; i++) {
	60	acl_e = &acl->a_entries[i];
	61	ace = &aclp->acl_entry[i];
	62
	63	/*
	64	* The tag is 32 bits on disk and 16 bits in core.
	65	*
	66	* Because every access to it goes through the core
	67	* format first this is not a problem.
	68	*/
	69	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	70	acl_e->e_perm = be16_to_cpu(ace->ae_perm);
	71
	72	switch (acl_e->e_tag) {
	73	case ACL_USER:
ba8adad5 CH	74	acl_e->e_uid = make_kuid(&init_user_ns,
ba8adad5 CH	75	be32_to_cpu(ace->ae_id));
288bbe0e	76	break;
ef14f0c1	77	case ACL_GROUP:
ba8adad5 CH	78	acl_e->e_gid = make_kgid(&init_user_ns,
ba8adad5 CH	79	be32_to_cpu(ace->ae_id));
ef14f0c1 CH	80	break;
	81	case ACL_USER_OBJ:
	82	case ACL_GROUP_OBJ:
	83	case ACL_MASK:
	84	case ACL_OTHER:
ef14f0c1 CH	85	break;
	86	default:
	87	goto fail;
	88	}
	89	}
	90	return acl;
	91
	92	fail:
	93	posix_acl_release(acl);
	94	return ERR_PTR(-EINVAL);
	95	}
	96
	97	STATIC void
	98	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	99	{
	100	const struct posix_acl_entry *acl_e;
	101	struct xfs_acl_entry *ace;
	102	int i;
	103
	104	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	105	for (i = 0; i < acl->a_count; i++) {
	106	ace = &aclp->acl_entry[i];
	107	acl_e = &acl->a_entries[i];
	108
	109	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
288bbe0e DE	110	switch (acl_e->e_tag) {
288bbe0e DE	111	case ACL_USER:
ba8adad5 CH	112	ace->ae_id = cpu_to_be32(
ba8adad5 CH	113	from_kuid(&init_user_ns, acl_e->e_uid));
288bbe0e DE	114	break;
288bbe0e DE	115	case ACL_GROUP:
ba8adad5 CH	116	ace->ae_id = cpu_to_be32(
ba8adad5 CH	117	from_kgid(&init_user_ns, acl_e->e_gid));
288bbe0e DE	118	break;
	119	default:
	120	ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
	121	break;
	122	}
	123
ef14f0c1 CH	124	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	125	}
	126	}
	127
ef14f0c1	128	struct posix_acl *
0cad6246	129	xfs_get_acl(struct inode *inode, int type, bool rcu)
ef14f0c1	130	{
e5171d7e CH	131	struct xfs_inode *ip = XFS_I(inode);
	132	struct xfs_mount *mp = ip->i_mount;
	133	struct posix_acl *acl = NULL;
	134	struct xfs_da_args args = {
	135	.dp = ip,
d5f0f49a	136	.attr_filter = XFS_ATTR_ROOT,
e5171d7e CH	137	.valuelen = XFS_ACL_MAX_SIZE(mp),
	138	};
	139	int error;
ef14f0c1	140
0cad6246 MS	141	if (rcu)
	142	return ERR_PTR(-ECHILD);
	143
4e34e719 CH	144	trace_xfs_get_acl(ip);
4e34e719 CH	145
ef14f0c1 CH	146	switch (type) {
ef14f0c1 CH	147	case ACL_TYPE_ACCESS:
e5171d7e	148	args.name = SGI_ACL_FILE;
ef14f0c1 CH	149	break;
ef14f0c1 CH	150	case ACL_TYPE_DEFAULT:
e5171d7e	151	args.name = SGI_ACL_DEFAULT;
ef14f0c1 CH	152	break;
ef14f0c1 CH	153	default:
1cbd20d8	154	BUG();
ef14f0c1	155	}
e5171d7e	156	args.namelen = strlen(args.name);
ef14f0c1	157
d49db18b CH	158	/*
	159	* If the attribute doesn't exist make sure we have a negative cache
	160	* entry, for any other error assume it is transient.
	161	*/
e5171d7e	162	error = xfs_attr_get(&args);
d49db18b	163	if (!error) {
e5171d7e CH	164	acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
e5171d7e CH	165	XFS_ACL_MAX_ENTRIES(mp));
d49db18b CH	166	} else if (error != -ENOATTR) {
d49db18b CH	167	acl = ERR_PTR(error);
ef14f0c1	168	}
d49db18b	169
49292576	170	kvfree(args.value);
ef14f0c1 CH	171	return acl;
	172	}
	173
8ba35875 JK	174	int
8ba35875 JK	175	__xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
ef14f0c1	176	{
a2544622 CH	177	struct xfs_inode *ip = XFS_I(inode);
	178	struct xfs_da_args args = {
	179	.dp = ip,
d5f0f49a	180	.attr_filter = XFS_ATTR_ROOT,
a2544622 CH	181	};
a2544622 CH	182	int error;
ef14f0c1	183
ef14f0c1 CH	184	switch (type) {
ef14f0c1 CH	185	case ACL_TYPE_ACCESS:
a2544622	186	args.name = SGI_ACL_FILE;
ef14f0c1 CH	187	break;
	188	case ACL_TYPE_DEFAULT:
	189	if (!S_ISDIR(inode->i_mode))
	190	return acl ? -EACCES : 0;
a2544622	191	args.name = SGI_ACL_DEFAULT;
ef14f0c1 CH	192	break;
	193	default:
	194	return -EINVAL;
	195	}
a2544622	196	args.namelen = strlen(args.name);
ef14f0c1 CH	197
ef14f0c1 CH	198	if (acl) {
ed02d13f	199	args.valuelen = XFS_ACL_SIZE(acl->a_count);
8ca79df8	200	args.value = kvzalloc(args.valuelen, GFP_KERNEL);
a2544622	201	if (!args.value)
fdd3ccee	202	return -ENOMEM;
a2544622	203	xfs_acl_to_disk(args.value, acl);
c27411d4 DW	204	error = xfs_attr_change(&args, XFS_ATTRUPDATE_UPSERT);
	205	kvfree(args.value);
	206	} else {
	207	error = xfs_attr_change(&args, XFS_ATTRUPDATE_REMOVE);
	208	/*
	209	* If the attribute didn't exist to start with that's fine.
	210	*/
	211	if (error == -ENOATTR)
	212	error = 0;
ef14f0c1 CH	213	}
	214
	215	if (!error)
1cbd20d8	216	set_cached_acl(inode, type, acl);
ef14f0c1 CH	217	return error;
	218	}
	219
ef14f0c1	220	static int
5d24ec4c CH	221	xfs_acl_set_mode(
	222	struct inode *inode,
	223	umode_t mode)
ef14f0c1	224	{
5d24ec4c CH	225	struct xfs_inode *ip = XFS_I(inode);
	226	struct xfs_mount *mp = ip->i_mount;
	227	struct xfs_trans *tp;
	228	int error;
ef14f0c1	229
5d24ec4c CH	230	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
	231	if (error)
	232	return error;
ef14f0c1	233
5d24ec4c CH	234	xfs_ilock(ip, XFS_ILOCK_EXCL);
	235	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	236	inode->i_mode = mode;
a0a415e3	237	inode_set_ctime_current(inode);
5d24ec4c	238	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
ef14f0c1	239
0560f31a	240	if (xfs_has_wsync(mp))
5d24ec4c CH	241	xfs_trans_set_sync(tp);
5d24ec4c CH	242	return xfs_trans_commit(tp);
ef14f0c1 CH	243	}
ef14f0c1 CH	244
ef14f0c1	245	int
13e83a49	246	xfs_set_acl(struct mnt_idmap idmap, struct dentry dentry,
549c7297	247	struct posix_acl *acl, int type)
ef14f0c1	248	{
67f2ffe3 DC	249	umode_t mode;
67f2ffe3 DC	250	bool set_mode = false;
431547b3	251	int error = 0;
138060ba	252	struct inode *inode = d_inode(dentry);
ef14f0c1	253
2401dc29	254	if (!acl)
ef14f0c1 CH	255	goto set_acl;
ef14f0c1 CH	256
4ae69fea	257	error = -E2BIG;
0a8aa193	258	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
2401dc29	259	return error;
ef14f0c1 CH	260
ef14f0c1 CH	261	if (type == ACL_TYPE_ACCESS) {
700b7940	262	error = posix_acl_update_mode(idmap, inode, &mode, &acl);
07393101 JK	263	if (error)
07393101 JK	264	return error;
67f2ffe3	265	set_mode = true;
ef14f0c1 CH	266	}
	267
	268	set_acl:
67f2ffe3 DC	269	/*
	270	* We set the mode after successfully updating the ACL xattr because the
	271	* xattr update can fail at ENOSPC and we don't want to change the mode
	272	* if the ACL update hasn't been applied.
	273	*/
5d24ec4c CH	274	error = __xfs_set_acl(inode, acl, type);
	275	if (!error && set_mode && mode != inode->i_mode)
	276	error = xfs_acl_set_mode(inode, mode);
67f2ffe3	277	return error;
ef14f0c1	278	}
5a3930e2 CH	279
	280	/*
	281	* Invalidate any cached ACLs if the user has bypassed the ACL interface.
	282	* We don't validate the content whatsoever so it is caller responsibility to
	283	* provide data in valid format and ensure i_mode is consistent.
	284	*/
	285	void
	286	xfs_forget_acl(
	287	struct inode *inode,
	288	const char *name)
	289	{
	290	if (!strcmp(name, SGI_ACL_FILE))
	291	forget_cached_acl(inode, ACL_TYPE_ACCESS);
	292	else if (!strcmp(name, SGI_ACL_DEFAULT))
	293	forget_cached_acl(inode, ACL_TYPE_DEFAULT);
	294	}