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![Eric W. Biederman](/assets/img/avatar_default.png)
- Pass the user namespace the uid and gid values in the xattr are stored in into posix_acl_from_xattr. - Pass the user namespace kuid and kgid values should be converted into when storing uid and gid values in an xattr in posix_acl_to_xattr. - Modify all callers of posix_acl_from_xattr and posix_acl_to_xattr to pass in &init_user_ns. In the short term this change is not strictly needed but it makes the code clearer. In the longer term this change is necessary to be able to mount filesystems outside of the initial user namespace that natively store posix acls in the linux xattr format. Cc: Theodore Tso <tytso@mit.edu> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
422 lines
8.7 KiB
C
422 lines
8.7 KiB
C
/*
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* Copyright (c) 2008, Christoph Hellwig
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "xfs.h"
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#include "xfs_acl.h"
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#include "xfs_attr.h"
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#include "xfs_bmap_btree.h"
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#include "xfs_inode.h"
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#include "xfs_vnodeops.h"
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#include "xfs_trace.h"
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#include <linux/slab.h>
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#include <linux/xattr.h>
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#include <linux/posix_acl_xattr.h>
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/*
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* Locking scheme:
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* - all ACL updates are protected by inode->i_mutex, which is taken before
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* calling into this file.
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*/
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STATIC struct posix_acl *
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xfs_acl_from_disk(struct xfs_acl *aclp)
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{
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struct posix_acl_entry *acl_e;
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struct posix_acl *acl;
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struct xfs_acl_entry *ace;
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unsigned int count, i;
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count = be32_to_cpu(aclp->acl_cnt);
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if (count > XFS_ACL_MAX_ENTRIES)
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return ERR_PTR(-EFSCORRUPTED);
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acl = posix_acl_alloc(count, GFP_KERNEL);
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if (!acl)
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return ERR_PTR(-ENOMEM);
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for (i = 0; i < count; i++) {
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acl_e = &acl->a_entries[i];
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ace = &aclp->acl_entry[i];
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/*
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* The tag is 32 bits on disk and 16 bits in core.
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*
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* Because every access to it goes through the core
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* format first this is not a problem.
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*/
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acl_e->e_tag = be32_to_cpu(ace->ae_tag);
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acl_e->e_perm = be16_to_cpu(ace->ae_perm);
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switch (acl_e->e_tag) {
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case ACL_USER:
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case ACL_GROUP:
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acl_e->e_id = be32_to_cpu(ace->ae_id);
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break;
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case ACL_USER_OBJ:
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case ACL_GROUP_OBJ:
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case ACL_MASK:
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case ACL_OTHER:
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acl_e->e_id = ACL_UNDEFINED_ID;
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break;
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default:
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goto fail;
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}
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}
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return acl;
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fail:
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posix_acl_release(acl);
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return ERR_PTR(-EINVAL);
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}
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STATIC void
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xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
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{
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const struct posix_acl_entry *acl_e;
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struct xfs_acl_entry *ace;
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int i;
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aclp->acl_cnt = cpu_to_be32(acl->a_count);
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for (i = 0; i < acl->a_count; i++) {
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ace = &aclp->acl_entry[i];
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acl_e = &acl->a_entries[i];
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ace->ae_tag = cpu_to_be32(acl_e->e_tag);
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ace->ae_id = cpu_to_be32(acl_e->e_id);
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ace->ae_perm = cpu_to_be16(acl_e->e_perm);
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}
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}
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struct posix_acl *
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xfs_get_acl(struct inode *inode, int type)
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{
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struct xfs_inode *ip = XFS_I(inode);
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struct posix_acl *acl;
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struct xfs_acl *xfs_acl;
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int len = sizeof(struct xfs_acl);
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unsigned char *ea_name;
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int error;
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acl = get_cached_acl(inode, type);
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if (acl != ACL_NOT_CACHED)
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return acl;
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trace_xfs_get_acl(ip);
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switch (type) {
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case ACL_TYPE_ACCESS:
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ea_name = SGI_ACL_FILE;
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break;
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case ACL_TYPE_DEFAULT:
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ea_name = SGI_ACL_DEFAULT;
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break;
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default:
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BUG();
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}
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/*
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* If we have a cached ACLs value just return it, not need to
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* go out to the disk.
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*/
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xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
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if (!xfs_acl)
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return ERR_PTR(-ENOMEM);
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error = -xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
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&len, ATTR_ROOT);
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if (error) {
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/*
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* If the attribute doesn't exist make sure we have a negative
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* cache entry, for any other error assume it is transient and
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* leave the cache entry as ACL_NOT_CACHED.
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*/
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if (error == -ENOATTR) {
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acl = NULL;
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goto out_update_cache;
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}
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goto out;
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}
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acl = xfs_acl_from_disk(xfs_acl);
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if (IS_ERR(acl))
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goto out;
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out_update_cache:
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set_cached_acl(inode, type, acl);
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out:
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kfree(xfs_acl);
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return acl;
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}
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STATIC int
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xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
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{
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struct xfs_inode *ip = XFS_I(inode);
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unsigned char *ea_name;
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int error;
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if (S_ISLNK(inode->i_mode))
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return -EOPNOTSUPP;
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switch (type) {
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case ACL_TYPE_ACCESS:
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ea_name = SGI_ACL_FILE;
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break;
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case ACL_TYPE_DEFAULT:
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if (!S_ISDIR(inode->i_mode))
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return acl ? -EACCES : 0;
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ea_name = SGI_ACL_DEFAULT;
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break;
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default:
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return -EINVAL;
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}
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if (acl) {
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struct xfs_acl *xfs_acl;
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int len;
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xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
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if (!xfs_acl)
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return -ENOMEM;
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xfs_acl_to_disk(xfs_acl, acl);
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len = sizeof(struct xfs_acl) -
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(sizeof(struct xfs_acl_entry) *
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(XFS_ACL_MAX_ENTRIES - acl->a_count));
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error = -xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
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len, ATTR_ROOT);
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kfree(xfs_acl);
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} else {
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/*
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* A NULL ACL argument means we want to remove the ACL.
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*/
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error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT);
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/*
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* If the attribute didn't exist to start with that's fine.
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*/
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if (error == -ENOATTR)
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error = 0;
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}
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if (!error)
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set_cached_acl(inode, type, acl);
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return error;
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}
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static int
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xfs_set_mode(struct inode *inode, umode_t mode)
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{
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int error = 0;
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if (mode != inode->i_mode) {
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struct iattr iattr;
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iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
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iattr.ia_mode = mode;
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iattr.ia_ctime = current_fs_time(inode->i_sb);
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error = -xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
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}
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return error;
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}
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static int
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xfs_acl_exists(struct inode *inode, unsigned char *name)
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{
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int len = sizeof(struct xfs_acl);
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return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
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ATTR_ROOT|ATTR_KERNOVAL) == 0);
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}
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int
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posix_acl_access_exists(struct inode *inode)
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{
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return xfs_acl_exists(inode, SGI_ACL_FILE);
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}
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int
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posix_acl_default_exists(struct inode *inode)
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{
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if (!S_ISDIR(inode->i_mode))
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return 0;
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return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
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}
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/*
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* No need for i_mutex because the inode is not yet exposed to the VFS.
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*/
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int
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xfs_inherit_acl(struct inode *inode, struct posix_acl *acl)
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{
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umode_t mode = inode->i_mode;
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int error = 0, inherit = 0;
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if (S_ISDIR(inode->i_mode)) {
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error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
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if (error)
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goto out;
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}
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error = posix_acl_create(&acl, GFP_KERNEL, &mode);
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if (error < 0)
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return error;
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/*
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* If posix_acl_create returns a positive value we need to
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* inherit a permission that can't be represented using the Unix
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* mode bits and we actually need to set an ACL.
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*/
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if (error > 0)
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inherit = 1;
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error = xfs_set_mode(inode, mode);
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if (error)
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goto out;
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if (inherit)
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error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
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out:
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posix_acl_release(acl);
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return error;
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}
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int
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xfs_acl_chmod(struct inode *inode)
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{
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struct posix_acl *acl;
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int error;
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if (S_ISLNK(inode->i_mode))
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return -EOPNOTSUPP;
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acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
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if (IS_ERR(acl) || !acl)
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return PTR_ERR(acl);
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error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
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if (error)
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return error;
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error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
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posix_acl_release(acl);
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return error;
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}
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static int
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xfs_xattr_acl_get(struct dentry *dentry, const char *name,
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void *value, size_t size, int type)
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{
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struct posix_acl *acl;
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int error;
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acl = xfs_get_acl(dentry->d_inode, type);
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if (IS_ERR(acl))
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return PTR_ERR(acl);
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if (acl == NULL)
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return -ENODATA;
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error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
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posix_acl_release(acl);
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return error;
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}
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static int
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xfs_xattr_acl_set(struct dentry *dentry, const char *name,
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const void *value, size_t size, int flags, int type)
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{
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struct inode *inode = dentry->d_inode;
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struct posix_acl *acl = NULL;
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int error = 0;
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if (flags & XATTR_CREATE)
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return -EINVAL;
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if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
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return value ? -EACCES : 0;
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if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
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return -EPERM;
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if (!value)
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goto set_acl;
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acl = posix_acl_from_xattr(&init_user_ns, value, size);
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if (!acl) {
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/*
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* acl_set_file(3) may request that we set default ACLs with
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* zero length -- defend (gracefully) against that here.
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*/
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goto out;
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}
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if (IS_ERR(acl)) {
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error = PTR_ERR(acl);
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goto out;
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}
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error = posix_acl_valid(acl);
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if (error)
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goto out_release;
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error = -EINVAL;
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if (acl->a_count > XFS_ACL_MAX_ENTRIES)
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goto out_release;
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if (type == ACL_TYPE_ACCESS) {
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umode_t mode = inode->i_mode;
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error = posix_acl_equiv_mode(acl, &mode);
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if (error <= 0) {
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posix_acl_release(acl);
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acl = NULL;
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if (error < 0)
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return error;
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}
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error = xfs_set_mode(inode, mode);
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if (error)
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goto out_release;
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}
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set_acl:
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error = xfs_set_acl(inode, type, acl);
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out_release:
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posix_acl_release(acl);
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out:
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return error;
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}
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const struct xattr_handler xfs_xattr_acl_access_handler = {
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.prefix = POSIX_ACL_XATTR_ACCESS,
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.flags = ACL_TYPE_ACCESS,
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.get = xfs_xattr_acl_get,
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.set = xfs_xattr_acl_set,
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};
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const struct xattr_handler xfs_xattr_acl_default_handler = {
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.prefix = POSIX_ACL_XATTR_DEFAULT,
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.flags = ACL_TYPE_DEFAULT,
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.get = xfs_xattr_acl_get,
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.set = xfs_xattr_acl_set,
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};
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