linux/fs/ceph/acl.c
Christian Brauner 700b794052
fs: port acl to mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:28 +01:00

264 lines
5.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/ceph/acl.c
*
* Copyright (C) 2013 Guangliang Zhao, <lucienchao@gmail.com>
*/
#include <linux/ceph/ceph_debug.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/posix_acl.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "super.h"
static inline void ceph_set_cached_acl(struct inode *inode,
int type, struct posix_acl *acl)
{
struct ceph_inode_info *ci = ceph_inode(inode);
spin_lock(&ci->i_ceph_lock);
if (__ceph_caps_issued_mask_metric(ci, CEPH_CAP_XATTR_SHARED, 0))
set_cached_acl(inode, type, acl);
else
forget_cached_acl(inode, type);
spin_unlock(&ci->i_ceph_lock);
}
struct posix_acl *ceph_get_acl(struct inode *inode, int type, bool rcu)
{
int size;
unsigned int retry_cnt = 0;
const char *name;
char *value = NULL;
struct posix_acl *acl;
if (rcu)
return ERR_PTR(-ECHILD);
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
break;
case ACL_TYPE_DEFAULT:
name = XATTR_NAME_POSIX_ACL_DEFAULT;
break;
default:
BUG();
}
retry:
size = __ceph_getxattr(inode, name, "", 0);
if (size > 0) {
value = kzalloc(size, GFP_NOFS);
if (!value)
return ERR_PTR(-ENOMEM);
size = __ceph_getxattr(inode, name, value, size);
}
if (size == -ERANGE && retry_cnt < 10) {
retry_cnt++;
kfree(value);
value = NULL;
goto retry;
}
if (size > 0) {
acl = posix_acl_from_xattr(&init_user_ns, value, size);
} else if (size == -ENODATA || size == 0) {
acl = NULL;
} else {
pr_err_ratelimited("get acl %llx.%llx failed, err=%d\n",
ceph_vinop(inode), size);
acl = ERR_PTR(-EIO);
}
kfree(value);
if (!IS_ERR(acl))
ceph_set_cached_acl(inode, type, acl);
return acl;
}
int ceph_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
struct posix_acl *acl, int type)
{
int ret = 0, size = 0;
const char *name = NULL;
char *value = NULL;
struct iattr newattrs;
struct inode *inode = d_inode(dentry);
struct timespec64 old_ctime = inode->i_ctime;
umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
if (ceph_snap(inode) != CEPH_NOSNAP) {
ret = -EROFS;
goto out;
}
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
if (acl) {
ret = posix_acl_update_mode(&nop_mnt_idmap, inode,
&new_mode, &acl);
if (ret)
goto out;
}
break;
case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode)) {
ret = acl ? -EINVAL : 0;
goto out;
}
name = XATTR_NAME_POSIX_ACL_DEFAULT;
break;
default:
ret = -EINVAL;
goto out;
}
if (acl) {
size = posix_acl_xattr_size(acl->a_count);
value = kmalloc(size, GFP_NOFS);
if (!value) {
ret = -ENOMEM;
goto out;
}
ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
if (ret < 0)
goto out_free;
}
if (new_mode != old_mode) {
newattrs.ia_ctime = current_time(inode);
newattrs.ia_mode = new_mode;
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
ret = __ceph_setattr(inode, &newattrs);
if (ret)
goto out_free;
}
ret = __ceph_setxattr(inode, name, value, size, 0);
if (ret) {
if (new_mode != old_mode) {
newattrs.ia_ctime = old_ctime;
newattrs.ia_mode = old_mode;
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
__ceph_setattr(inode, &newattrs);
}
goto out_free;
}
ceph_set_cached_acl(inode, type, acl);
out_free:
kfree(value);
out:
return ret;
}
int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
struct ceph_acl_sec_ctx *as_ctx)
{
struct posix_acl *acl, *default_acl;
size_t val_size1 = 0, val_size2 = 0;
struct ceph_pagelist *pagelist = NULL;
void *tmp_buf = NULL;
int err;
err = posix_acl_create(dir, mode, &default_acl, &acl);
if (err)
return err;
if (acl) {
err = posix_acl_equiv_mode(acl, mode);
if (err < 0)
goto out_err;
if (err == 0) {
posix_acl_release(acl);
acl = NULL;
}
}
if (!default_acl && !acl)
return 0;
if (acl)
val_size1 = posix_acl_xattr_size(acl->a_count);
if (default_acl)
val_size2 = posix_acl_xattr_size(default_acl->a_count);
err = -ENOMEM;
tmp_buf = kmalloc(max(val_size1, val_size2), GFP_KERNEL);
if (!tmp_buf)
goto out_err;
pagelist = ceph_pagelist_alloc(GFP_KERNEL);
if (!pagelist)
goto out_err;
err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
if (err)
goto out_err;
ceph_pagelist_encode_32(pagelist, acl && default_acl ? 2 : 1);
if (acl) {
size_t len = strlen(XATTR_NAME_POSIX_ACL_ACCESS);
err = ceph_pagelist_reserve(pagelist, len + val_size1 + 8);
if (err)
goto out_err;
ceph_pagelist_encode_string(pagelist, XATTR_NAME_POSIX_ACL_ACCESS,
len);
err = posix_acl_to_xattr(&init_user_ns, acl,
tmp_buf, val_size1);
if (err < 0)
goto out_err;
ceph_pagelist_encode_32(pagelist, val_size1);
ceph_pagelist_append(pagelist, tmp_buf, val_size1);
}
if (default_acl) {
size_t len = strlen(XATTR_NAME_POSIX_ACL_DEFAULT);
err = ceph_pagelist_reserve(pagelist, len + val_size2 + 8);
if (err)
goto out_err;
ceph_pagelist_encode_string(pagelist,
XATTR_NAME_POSIX_ACL_DEFAULT, len);
err = posix_acl_to_xattr(&init_user_ns, default_acl,
tmp_buf, val_size2);
if (err < 0)
goto out_err;
ceph_pagelist_encode_32(pagelist, val_size2);
ceph_pagelist_append(pagelist, tmp_buf, val_size2);
}
kfree(tmp_buf);
as_ctx->acl = acl;
as_ctx->default_acl = default_acl;
as_ctx->pagelist = pagelist;
return 0;
out_err:
posix_acl_release(acl);
posix_acl_release(default_acl);
kfree(tmp_buf);
if (pagelist)
ceph_pagelist_release(pagelist);
return err;
}
void ceph_init_inode_acls(struct inode *inode, struct ceph_acl_sec_ctx *as_ctx)
{
if (!inode)
return;
ceph_set_cached_acl(inode, ACL_TYPE_ACCESS, as_ctx->acl);
ceph_set_cached_acl(inode, ACL_TYPE_DEFAULT, as_ctx->default_acl);
}