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linux-next/fs/orangefs/acl.c
Mike Marshall 476af91933 orangefs: posix acl fix...
Al Viro pointed out that I broke some acl functionality...

 * ACLs could not be fully removed
 * posix_acl_chmod would be called while the old ACL was still cached
 * new mode propagated to orangefs server before ACL.

... when I tried to make sure that modes that got changed as a
result of ACL-sets would be sent back to the orangefs server.

Not wanting to try and change the code without having some cases to
test it with, I began to hunt for setfacl examples that were expressible
in pure mode. Along the way I found examples like the following
which confused me:

  user A had a file (/home/A/asdf) with mode 740
  user B was in user A's group
  user C was not in user A's group

  setfacl -m u:C:rwx /home/A/asdf

  The above setfacl caused ls -l /home/A/asdf to show a mode of 770,
  making it appear that all users in user A's group now had full access
  to /home/A/asdf, however, user B still only had read acces. Madness.

Anywho, I finally found that the above (whacky as it is) appears to
be "posixly on purpose" and explained in acl(5):

  If the ACL has an ACL_MASK entry, the group permissions correspond
  to the permissions of the ACL_MASK entry.

Signed-off-by: Mike Marshall <hubcap@omnibond.com>
2020-07-28 12:52:53 -04:00

194 lines
4.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* (C) 2001 Clemson University and The University of Chicago
*
* See COPYING in top-level directory.
*/
#include "protocol.h"
#include "orangefs-kernel.h"
#include "orangefs-bufmap.h"
#include <linux/posix_acl_xattr.h>
struct posix_acl *orangefs_get_acl(struct inode *inode, int type)
{
struct posix_acl *acl;
int ret;
char *key = NULL, *value = NULL;
switch (type) {
case ACL_TYPE_ACCESS:
key = XATTR_NAME_POSIX_ACL_ACCESS;
break;
case ACL_TYPE_DEFAULT:
key = XATTR_NAME_POSIX_ACL_DEFAULT;
break;
default:
gossip_err("orangefs_get_acl: bogus value of type %d\n", type);
return ERR_PTR(-EINVAL);
}
/*
* Rather than incurring a network call just to determine the exact
* length of the attribute, I just allocate a max length to save on
* the network call. Conceivably, we could pass NULL to
* orangefs_inode_getxattr() to probe the length of the value, but
* I don't do that for now.
*/
value = kmalloc(ORANGEFS_MAX_XATTR_VALUELEN, GFP_KERNEL);
if (!value)
return ERR_PTR(-ENOMEM);
gossip_debug(GOSSIP_ACL_DEBUG,
"inode %pU, key %s, type %d\n",
get_khandle_from_ino(inode),
key,
type);
ret = orangefs_inode_getxattr(inode, key, value,
ORANGEFS_MAX_XATTR_VALUELEN);
/* if the key exists, convert it to an in-memory rep */
if (ret > 0) {
acl = posix_acl_from_xattr(&init_user_ns, value, ret);
} else if (ret == -ENODATA || ret == -ENOSYS) {
acl = NULL;
} else {
gossip_err("inode %pU retrieving acl's failed with error %d\n",
get_khandle_from_ino(inode),
ret);
acl = ERR_PTR(ret);
}
/* kfree(NULL) is safe, so don't worry if value ever got used */
kfree(value);
return acl;
}
static int __orangefs_set_acl(struct inode *inode, struct posix_acl *acl,
int type)
{
int error = 0;
void *value = NULL;
size_t size = 0;
const char *name = NULL;
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:
gossip_err("%s: invalid type %d!\n", __func__, type);
return -EINVAL;
}
gossip_debug(GOSSIP_ACL_DEBUG,
"%s: inode %pU, key %s type %d\n",
__func__, get_khandle_from_ino(inode),
name,
type);
if (acl) {
size = posix_acl_xattr_size(acl->a_count);
value = kmalloc(size, GFP_KERNEL);
if (!value)
return -ENOMEM;
error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
if (error < 0)
goto out;
}
gossip_debug(GOSSIP_ACL_DEBUG,
"%s: name %s, value %p, size %zd, acl %p\n",
__func__, name, value, size, acl);
/*
* Go ahead and set the extended attribute now. NOTE: Suppose acl
* was NULL, then value will be NULL and size will be 0 and that
* will xlate to a removexattr. However, we don't want removexattr
* complain if attributes does not exist.
*/
error = orangefs_inode_setxattr(inode, name, value, size, 0);
out:
kfree(value);
if (!error)
set_cached_acl(inode, type, acl);
return error;
}
int orangefs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
int error;
struct iattr iattr;
int rc;
memset(&iattr, 0, sizeof iattr);
if (type == ACL_TYPE_ACCESS && acl) {
/*
* posix_acl_update_mode checks to see if the permissions
* described by the ACL can be encoded into the
* object's mode. If so, it sets "acl" to NULL
* and "mode" to the new desired value. It is up to
* us to propagate the new mode back to the server...
*/
error = posix_acl_update_mode(inode, &iattr.ia_mode, &acl);
if (error) {
gossip_err("%s: posix_acl_update_mode err: %d\n",
__func__,
error);
return error;
}
if (inode->i_mode != iattr.ia_mode)
iattr.ia_valid = ATTR_MODE;
}
rc = __orangefs_set_acl(inode, acl, type);
if (!rc && (iattr.ia_valid == ATTR_MODE))
rc = __orangefs_setattr(inode, &iattr);
return rc;
}
int orangefs_init_acl(struct inode *inode, struct inode *dir)
{
struct posix_acl *default_acl, *acl;
umode_t mode = inode->i_mode;
struct iattr iattr;
int error = 0;
error = posix_acl_create(dir, &mode, &default_acl, &acl);
if (error)
return error;
if (default_acl) {
error = __orangefs_set_acl(inode, default_acl,
ACL_TYPE_DEFAULT);
posix_acl_release(default_acl);
} else {
inode->i_default_acl = NULL;
}
if (acl) {
if (!error)
error = __orangefs_set_acl(inode, acl, ACL_TYPE_ACCESS);
posix_acl_release(acl);
} else {
inode->i_acl = NULL;
}
/* If mode of the inode was changed, then do a forcible ->setattr */
if (mode != inode->i_mode) {
memset(&iattr, 0, sizeof iattr);
inode->i_mode = mode;
iattr.ia_mode = mode;
iattr.ia_valid |= ATTR_MODE;
__orangefs_setattr(inode, &iattr);
}
return error;
}