// 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);
}
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