linux/fs/cifs/xattr.c
Steve French c4f7173ac3 smb3: create smb3 equivalent alias for cifs pseudo-xattrs
We really, really don't want to be encouraging people to use
cifs (the dialect) since it is insecure, so to avoid confusion
we want to move them to names which include 'smb3' instead of
'cifs' - so this simply creates an alias for the pseudo-xattrs

e.g. can now do:
getfattr -n user.smb3.creationtime /mnt1/file
and
getfattr -n user.smb3.dosattrib /mnt1/file
and
getfattr -n system.smb3_acl /mnt1/file

instead of forcing you to use the string 'cifs' in
these (e.g. getfattr -n system.cifs_acl /mnt1/file)

Signed-off-by: Steve French <stfrench@microsoft.com>
2018-08-10 18:46:58 -05:00

412 lines
10 KiB
C

/*
* fs/cifs/xattr.c
*
* Copyright (c) International Business Machines Corp., 2003, 2007
* Author(s): Steve French (sfrench@us.ibm.com)
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/posix_acl_xattr.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "cifs_unicode.h"
#define MAX_EA_VALUE_SIZE 65535
#define CIFS_XATTR_CIFS_ACL "system.cifs_acl"
#define CIFS_XATTR_ATTRIB "cifs.dosattrib" /* full name: user.cifs.dosattrib */
#define CIFS_XATTR_CREATETIME "cifs.creationtime" /* user.cifs.creationtime */
/*
* Although these three are just aliases for the above, need to move away from
* confusing users and using the 20+ year old term 'cifs' when it is no longer
* secure, replaced by SMB2 (then even more highly secure SMB3) many years ago
*/
#define SMB3_XATTR_CIFS_ACL "system.smb3_acl"
#define SMB3_XATTR_ATTRIB "smb3.dosattrib" /* full name: user.smb3.dosattrib */
#define SMB3_XATTR_CREATETIME "smb3.creationtime" /* user.smb3.creationtime */
/* BB need to add server (Samba e.g) support for security and trusted prefix */
enum { XATTR_USER, XATTR_CIFS_ACL, XATTR_ACL_ACCESS, XATTR_ACL_DEFAULT };
static int cifs_xattr_set(const struct xattr_handler *handler,
struct dentry *dentry, struct inode *inode,
const char *name, const void *value,
size_t size, int flags)
{
int rc = -EOPNOTSUPP;
unsigned int xid;
struct super_block *sb = dentry->d_sb;
struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
char *full_path;
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = get_xid();
full_path = build_path_from_dentry(dentry);
if (full_path == NULL) {
rc = -ENOMEM;
goto out;
}
/* return dos attributes as pseudo xattr */
/* return alt name if available as pseudo attr */
/* if proc/fs/cifs/streamstoxattr is set then
search server for EAs or streams to
returns as xattrs */
if (size > MAX_EA_VALUE_SIZE) {
cifs_dbg(FYI, "size of EA value too large\n");
rc = -EOPNOTSUPP;
goto out;
}
switch (handler->flags) {
case XATTR_USER:
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto out;
if (pTcon->ses->server->ops->set_EA)
rc = pTcon->ses->server->ops->set_EA(xid, pTcon,
full_path, name, value, (__u16)size,
cifs_sb->local_nls, cifs_sb);
break;
case XATTR_CIFS_ACL: {
#ifdef CONFIG_CIFS_ACL
struct cifs_ntsd *pacl;
if (!value)
goto out;
pacl = kmalloc(size, GFP_KERNEL);
if (!pacl) {
rc = -ENOMEM;
} else {
memcpy(pacl, value, size);
if (value &&
pTcon->ses->server->ops->set_acl)
rc = pTcon->ses->server->ops->set_acl(pacl,
size, inode,
full_path, CIFS_ACL_DACL);
else
rc = -EOPNOTSUPP;
if (rc == 0) /* force revalidate of the inode */
CIFS_I(inode)->time = 0;
kfree(pacl);
}
#endif /* CONFIG_CIFS_ACL */
break;
}
case XATTR_ACL_ACCESS:
#ifdef CONFIG_CIFS_POSIX
if (!value)
goto out;
if (sb->s_flags & SB_POSIXACL)
rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
value, (const int)size,
ACL_TYPE_ACCESS, cifs_sb->local_nls,
cifs_remap(cifs_sb));
#endif /* CONFIG_CIFS_POSIX */
break;
case XATTR_ACL_DEFAULT:
#ifdef CONFIG_CIFS_POSIX
if (!value)
goto out;
if (sb->s_flags & SB_POSIXACL)
rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
value, (const int)size,
ACL_TYPE_DEFAULT, cifs_sb->local_nls,
cifs_remap(cifs_sb));
#endif /* CONFIG_CIFS_POSIX */
break;
}
out:
kfree(full_path);
free_xid(xid);
cifs_put_tlink(tlink);
return rc;
}
static int cifs_attrib_get(struct dentry *dentry,
struct inode *inode, void *value,
size_t size)
{
ssize_t rc;
__u32 *pattribute;
rc = cifs_revalidate_dentry_attr(dentry);
if (rc)
return rc;
if ((value == NULL) || (size == 0))
return sizeof(__u32);
else if (size < sizeof(__u32))
return -ERANGE;
/* return dos attributes as pseudo xattr */
pattribute = (__u32 *)value;
*pattribute = CIFS_I(inode)->cifsAttrs;
return sizeof(__u32);
}
static int cifs_creation_time_get(struct dentry *dentry, struct inode *inode,
void *value, size_t size)
{
ssize_t rc;
__u64 * pcreatetime;
rc = cifs_revalidate_dentry_attr(dentry);
if (rc)
return rc;
if ((value == NULL) || (size == 0))
return sizeof(__u64);
else if (size < sizeof(__u64))
return -ERANGE;
/* return dos attributes as pseudo xattr */
pcreatetime = (__u64 *)value;
*pcreatetime = CIFS_I(inode)->createtime;
return sizeof(__u64);
}
static int cifs_xattr_get(const struct xattr_handler *handler,
struct dentry *dentry, struct inode *inode,
const char *name, void *value, size_t size)
{
ssize_t rc = -EOPNOTSUPP;
unsigned int xid;
struct super_block *sb = dentry->d_sb;
struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
char *full_path;
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = get_xid();
full_path = build_path_from_dentry(dentry);
if (full_path == NULL) {
rc = -ENOMEM;
goto out;
}
/* return alt name if available as pseudo attr */
switch (handler->flags) {
case XATTR_USER:
cifs_dbg(FYI, "%s:querying user xattr %s\n", __func__, name);
if ((strcmp(name, CIFS_XATTR_ATTRIB) == 0) ||
(strcmp(name, SMB3_XATTR_ATTRIB) == 0)) {
rc = cifs_attrib_get(dentry, inode, value, size);
break;
} else if ((strcmp(name, CIFS_XATTR_CREATETIME) == 0) ||
(strcmp(name, SMB3_XATTR_CREATETIME) == 0)) {
rc = cifs_creation_time_get(dentry, inode, value, size);
break;
}
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto out;
if (pTcon->ses->server->ops->query_all_EAs)
rc = pTcon->ses->server->ops->query_all_EAs(xid, pTcon,
full_path, name, value, size, cifs_sb);
break;
case XATTR_CIFS_ACL: {
#ifdef CONFIG_CIFS_ACL
u32 acllen;
struct cifs_ntsd *pacl;
if (pTcon->ses->server->ops->get_acl == NULL)
goto out; /* rc already EOPNOTSUPP */
pacl = pTcon->ses->server->ops->get_acl(cifs_sb,
inode, full_path, &acllen);
if (IS_ERR(pacl)) {
rc = PTR_ERR(pacl);
cifs_dbg(VFS, "%s: error %zd getting sec desc\n",
__func__, rc);
} else {
if (value) {
if (acllen > size)
acllen = -ERANGE;
else
memcpy(value, pacl, acllen);
}
rc = acllen;
kfree(pacl);
}
#endif /* CONFIG_CIFS_ACL */
break;
}
case XATTR_ACL_ACCESS:
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & SB_POSIXACL)
rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
value, size, ACL_TYPE_ACCESS,
cifs_sb->local_nls,
cifs_remap(cifs_sb));
#endif /* CONFIG_CIFS_POSIX */
break;
case XATTR_ACL_DEFAULT:
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & SB_POSIXACL)
rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
value, size, ACL_TYPE_DEFAULT,
cifs_sb->local_nls,
cifs_remap(cifs_sb));
#endif /* CONFIG_CIFS_POSIX */
break;
}
/* We could add an additional check for streams ie
if proc/fs/cifs/streamstoxattr is set then
search server for EAs or streams to
returns as xattrs */
if (rc == -EINVAL)
rc = -EOPNOTSUPP;
out:
kfree(full_path);
free_xid(xid);
cifs_put_tlink(tlink);
return rc;
}
ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
{
ssize_t rc = -EOPNOTSUPP;
unsigned int xid;
struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
char *full_path;
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
return -EOPNOTSUPP;
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = get_xid();
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
goto list_ea_exit;
}
/* return dos attributes as pseudo xattr */
/* return alt name if available as pseudo attr */
/* if proc/fs/cifs/streamstoxattr is set then
search server for EAs or streams to
returns as xattrs */
if (pTcon->ses->server->ops->query_all_EAs)
rc = pTcon->ses->server->ops->query_all_EAs(xid, pTcon,
full_path, NULL, data, buf_size, cifs_sb);
list_ea_exit:
kfree(full_path);
free_xid(xid);
cifs_put_tlink(tlink);
return rc;
}
static const struct xattr_handler cifs_user_xattr_handler = {
.prefix = XATTR_USER_PREFIX,
.flags = XATTR_USER,
.get = cifs_xattr_get,
.set = cifs_xattr_set,
};
/* os2.* attributes are treated like user.* attributes */
static const struct xattr_handler cifs_os2_xattr_handler = {
.prefix = XATTR_OS2_PREFIX,
.flags = XATTR_USER,
.get = cifs_xattr_get,
.set = cifs_xattr_set,
};
static const struct xattr_handler cifs_cifs_acl_xattr_handler = {
.name = CIFS_XATTR_CIFS_ACL,
.flags = XATTR_CIFS_ACL,
.get = cifs_xattr_get,
.set = cifs_xattr_set,
};
/*
* Although this is just an alias for the above, need to move away from
* confusing users and using the 20 year old term 'cifs' when it is no
* longer secure and was replaced by SMB2/SMB3 a long time ago, and
* SMB3 and later are highly secure.
*/
static const struct xattr_handler smb3_acl_xattr_handler = {
.name = SMB3_XATTR_CIFS_ACL,
.flags = XATTR_CIFS_ACL,
.get = cifs_xattr_get,
.set = cifs_xattr_set,
};
static const struct xattr_handler cifs_posix_acl_access_xattr_handler = {
.name = XATTR_NAME_POSIX_ACL_ACCESS,
.flags = XATTR_ACL_ACCESS,
.get = cifs_xattr_get,
.set = cifs_xattr_set,
};
static const struct xattr_handler cifs_posix_acl_default_xattr_handler = {
.name = XATTR_NAME_POSIX_ACL_DEFAULT,
.flags = XATTR_ACL_DEFAULT,
.get = cifs_xattr_get,
.set = cifs_xattr_set,
};
const struct xattr_handler *cifs_xattr_handlers[] = {
&cifs_user_xattr_handler,
&cifs_os2_xattr_handler,
&cifs_cifs_acl_xattr_handler,
&smb3_acl_xattr_handler, /* alias for above since avoiding "cifs" */
&cifs_posix_acl_access_xattr_handler,
&cifs_posix_acl_default_xattr_handler,
NULL
};