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linux/fs/cifs/xattr.c
Shirish Pargaonkar a5ff376966 cifs: Call id to SID mapping functions to change owner/group (try #4 repost) 
Now build security descriptor to change either owner or group at the
server.  Initially security descriptor was built to change only
(D)ACL, that functionality has been extended.

When either an Owner or a Group of a file object at the server is changed,
rest of security descriptor remains same (DACL etc.).

To set security descriptor, it is necessary to open that file
with permission bits of either WRITE_DAC if DACL is being modified or
WRITE_OWNER (Take Ownership) if Owner or Group is being changed.

It is the server that decides whether a set security descriptor with
either owner or group change succeeds or not.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2011-10-17 09:11:11 -05:00

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/*
* 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 "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#define MAX_EA_VALUE_SIZE 65535
#define CIFS_XATTR_DOS_ATTRIB "user.DosAttrib"
#define CIFS_XATTR_CIFS_ACL "system.cifs_acl"
#define CIFS_XATTR_USER_PREFIX "user."
#define CIFS_XATTR_SYSTEM_PREFIX "system."
#define CIFS_XATTR_OS2_PREFIX "os2."
#define CIFS_XATTR_SECURITY_PREFIX "security."
#define CIFS_XATTR_TRUSTED_PREFIX "trusted."
#define XATTR_TRUSTED_PREFIX_LEN 8
#define XATTR_SECURITY_PREFIX_LEN 9
/* BB need to add server (Samba e.g) support for security and trusted prefix */
int cifs_removexattr(struct dentry *direntry, const char *ea_name)
{
int rc = -EOPNOTSUPP;
#ifdef CONFIG_CIFS_XATTR
int xid;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
struct super_block *sb;
char *full_path = NULL;
if (direntry == NULL)
return -EIO;
if (direntry->d_inode == NULL)
return -EIO;
sb = direntry->d_inode->i_sb;
if (sb == NULL)
return -EIO;
cifs_sb = CIFS_SB(sb);
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = GetXid();
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
goto remove_ea_exit;
}
if (ea_name == NULL) {
cFYI(1, "Null xattr names not supported");
} else if (strncmp(ea_name, CIFS_XATTR_USER_PREFIX, 5)
&& (strncmp(ea_name, CIFS_XATTR_OS2_PREFIX, 4))) {
cFYI(1,
"illegal xattr request %s (only user namespace supported)",
ea_name);
/* BB what if no namespace prefix? */
/* Should we just pass them to server, except for
system and perhaps security prefixes? */
} else {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto remove_ea_exit;
ea_name += 5; /* skip past user. prefix */
rc = CIFSSMBSetEA(xid, pTcon, full_path, ea_name, NULL,
(__u16)0, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
}
remove_ea_exit:
kfree(full_path);
FreeXid(xid);
cifs_put_tlink(tlink);
#endif
return rc;
}
int cifs_setxattr(struct dentry *direntry, const char *ea_name,
const void *ea_value, size_t value_size, int flags)
{
int rc = -EOPNOTSUPP;
#ifdef CONFIG_CIFS_XATTR
int xid;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
struct super_block *sb;
char *full_path;
struct cifs_ntsd *pacl;
if (direntry == NULL)
return -EIO;
if (direntry->d_inode == NULL)
return -EIO;
sb = direntry->d_inode->i_sb;
if (sb == NULL)
return -EIO;
cifs_sb = CIFS_SB(sb);
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = GetXid();
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
goto set_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 (value_size > MAX_EA_VALUE_SIZE) {
cFYI(1, "size of EA value too large");
rc = -EOPNOTSUPP;
goto set_ea_exit;
}
if (ea_name == NULL) {
cFYI(1, "Null xattr names not supported");
} else if (strncmp(ea_name, CIFS_XATTR_USER_PREFIX, 5) == 0) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto set_ea_exit;
if (strncmp(ea_name, CIFS_XATTR_DOS_ATTRIB, 14) == 0)
cFYI(1, "attempt to set cifs inode metadata");
ea_name += 5; /* skip past user. prefix */
rc = CIFSSMBSetEA(xid, pTcon, full_path, ea_name, ea_value,
(__u16)value_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
} else if (strncmp(ea_name, CIFS_XATTR_OS2_PREFIX, 4) == 0) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto set_ea_exit;
ea_name += 4; /* skip past os2. prefix */
rc = CIFSSMBSetEA(xid, pTcon, full_path, ea_name, ea_value,
(__u16)value_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
} else if (strncmp(ea_name, CIFS_XATTR_CIFS_ACL,
strlen(CIFS_XATTR_CIFS_ACL)) == 0) {
pacl = kmalloc(value_size, GFP_KERNEL);
if (!pacl) {
cFYI(1, "%s: Can't allocate memory for ACL",
__func__);
rc = -ENOMEM;
} else {
#ifdef CONFIG_CIFS_ACL
memcpy(pacl, ea_value, value_size);
rc = set_cifs_acl(pacl, value_size,
direntry->d_inode, full_path, CIFS_ACL_DACL);
if (rc == 0) /* force revalidate of the inode */
CIFS_I(direntry->d_inode)->time = 0;
kfree(pacl);
#else
cFYI(1, "Set CIFS ACL not supported yet");
#endif /* CONFIG_CIFS_ACL */
}
} else {
int temp;
temp = strncmp(ea_name, POSIX_ACL_XATTR_ACCESS,
strlen(POSIX_ACL_XATTR_ACCESS));
if (temp == 0) {
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & MS_POSIXACL)
rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
ea_value, (const int)value_size,
ACL_TYPE_ACCESS, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
cFYI(1, "set POSIX ACL rc %d", rc);
#else
cFYI(1, "set POSIX ACL not supported");
#endif
} else if (strncmp(ea_name, POSIX_ACL_XATTR_DEFAULT,
strlen(POSIX_ACL_XATTR_DEFAULT)) == 0) {
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & MS_POSIXACL)
rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
ea_value, (const int)value_size,
ACL_TYPE_DEFAULT, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
cFYI(1, "set POSIX default ACL rc %d", rc);
#else
cFYI(1, "set default POSIX ACL not supported");
#endif
} else {
cFYI(1, "illegal xattr request %s (only user namespace"
" supported)", ea_name);
/* BB what if no namespace prefix? */
/* Should we just pass them to server, except for
system and perhaps security prefixes? */
}
}
set_ea_exit:
kfree(full_path);
FreeXid(xid);
cifs_put_tlink(tlink);
#endif
return rc;
}
ssize_t cifs_getxattr(struct dentry *direntry, const char *ea_name,
void *ea_value, size_t buf_size)
{
ssize_t rc = -EOPNOTSUPP;
#ifdef CONFIG_CIFS_XATTR
int xid;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
struct super_block *sb;
char *full_path;
if (direntry == NULL)
return -EIO;
if (direntry->d_inode == NULL)
return -EIO;
sb = direntry->d_inode->i_sb;
if (sb == NULL)
return -EIO;
cifs_sb = CIFS_SB(sb);
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = GetXid();
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
goto get_ea_exit;
}
/* return dos attributes as pseudo xattr */
/* return alt name if available as pseudo attr */
if (ea_name == NULL) {
cFYI(1, "Null xattr names not supported");
} else if (strncmp(ea_name, CIFS_XATTR_USER_PREFIX, 5) == 0) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto get_ea_exit;
if (strncmp(ea_name, CIFS_XATTR_DOS_ATTRIB, 14) == 0) {
cFYI(1, "attempt to query cifs inode metadata");
/* revalidate/getattr then populate from inode */
} /* BB add else when above is implemented */
ea_name += 5; /* skip past user. prefix */
rc = CIFSSMBQAllEAs(xid, pTcon, full_path, ea_name, ea_value,
buf_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
} else if (strncmp(ea_name, CIFS_XATTR_OS2_PREFIX, 4) == 0) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto get_ea_exit;
ea_name += 4; /* skip past os2. prefix */
rc = CIFSSMBQAllEAs(xid, pTcon, full_path, ea_name, ea_value,
buf_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
} else if (strncmp(ea_name, POSIX_ACL_XATTR_ACCESS,
strlen(POSIX_ACL_XATTR_ACCESS)) == 0) {
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & MS_POSIXACL)
rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
ea_value, buf_size, ACL_TYPE_ACCESS,
cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
#else
cFYI(1, "Query POSIX ACL not supported yet");
#endif /* CONFIG_CIFS_POSIX */
} else if (strncmp(ea_name, POSIX_ACL_XATTR_DEFAULT,
strlen(POSIX_ACL_XATTR_DEFAULT)) == 0) {
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & MS_POSIXACL)
rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
ea_value, buf_size, ACL_TYPE_DEFAULT,
cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
#else
cFYI(1, "Query POSIX default ACL not supported yet");
#endif /* CONFIG_CIFS_POSIX */
} else if (strncmp(ea_name, CIFS_XATTR_CIFS_ACL,
strlen(CIFS_XATTR_CIFS_ACL)) == 0) {
#ifdef CONFIG_CIFS_ACL
u32 acllen;
struct cifs_ntsd *pacl;
pacl = get_cifs_acl(cifs_sb, direntry->d_inode,
full_path, &acllen);
if (IS_ERR(pacl)) {
rc = PTR_ERR(pacl);
cERROR(1, "%s: error %zd getting sec desc",
__func__, rc);
} else {
if (ea_value) {
if (acllen > buf_size)
acllen = -ERANGE;
else
memcpy(ea_value, pacl, acllen);
}
rc = acllen;
kfree(pacl);
}
#else
cFYI(1, "Query CIFS ACL not supported yet");
#endif /* CONFIG_CIFS_ACL */
} else if (strncmp(ea_name,
CIFS_XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) == 0) {
cFYI(1, "Trusted xattr namespace not supported yet");
} else if (strncmp(ea_name,
CIFS_XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) == 0) {
cFYI(1, "Security xattr namespace not supported yet");
} else
cFYI(1,
"illegal xattr request %s (only user namespace supported)",
ea_name);
/* 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;
get_ea_exit:
kfree(full_path);
FreeXid(xid);
cifs_put_tlink(tlink);
#endif
return rc;
}
ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
{
ssize_t rc = -EOPNOTSUPP;
#ifdef CONFIG_CIFS_XATTR
int xid;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
struct super_block *sb;
char *full_path;
if (direntry == NULL)
return -EIO;
if (direntry->d_inode == NULL)
return -EIO;
sb = direntry->d_inode->i_sb;
if (sb == NULL)
return -EIO;
cifs_sb = CIFS_SB(sb);
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 = GetXid();
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 */
rc = CIFSSMBQAllEAs(xid, pTcon, full_path, NULL, data,
buf_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
list_ea_exit:
kfree(full_path);
FreeXid(xid);
cifs_put_tlink(tlink);
#endif
return rc;
}
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