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CIFS: Add support for setting owner info, dos attributes, and create …
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…time

This is needed for backup/restore scenarios among others.

Add extended attribute "system.cifs_ntsd" (and alias "system.smb3_ntsd")
to allow for setting owner and DACL in the security descriptor. This is in
addition to the existing "system.cifs_acl" and "system.smb3_acl" attributes
that allow for setting DACL only. Add support for setting creation time and
dos attributes using set_file_info() calls to complement the existing
support for getting these attributes via query_path_info() calls.

Signed-off-by: Boris Protopopov <bprotopopov@hotmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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@bprotopopov
bprotopopov authored and Steve French committed Jan 27, 2020
1 parent c4985c3 commit 438471b
Showing 1 changed file with 117 additions and 11 deletions.
128 changes: 117 additions & 11 deletions fs/cifs/xattr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,20 +32,71 @@
#include "cifs_unicode.h"

#define MAX_EA_VALUE_SIZE CIFSMaxBufSize
#define CIFS_XATTR_CIFS_ACL "system.cifs_acl"
#define CIFS_XATTR_CIFS_ACL "system.cifs_acl" /* DACL only */
#define CIFS_XATTR_CIFS_NTSD "system.cifs_ntsd" /* owner plus DACL */
#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_CIFS_ACL "system.smb3_acl" /* DACL only */
#define SMB3_XATTR_CIFS_NTSD "system.smb3_ntsd" /* owner plus DACL */
#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 };
enum { XATTR_USER, XATTR_CIFS_ACL, XATTR_ACL_ACCESS, XATTR_ACL_DEFAULT,
XATTR_CIFS_NTSD };

static int cifs_attrib_set(unsigned int xid, struct cifs_tcon *pTcon,
struct inode *inode, char *full_path,
const void *value, size_t size)
{
ssize_t rc = -EOPNOTSUPP;
__u32 *pattrib = (__u32 *)value;
__u32 attrib;
FILE_BASIC_INFO info_buf;

if ((value == NULL) || (size != sizeof(__u32)))
return -ERANGE;

memset(&info_buf, 0, sizeof(info_buf));
attrib = *pattrib;
info_buf.Attributes = cpu_to_le32(attrib);
if (pTcon->ses->server->ops->set_file_info)
rc = pTcon->ses->server->ops->set_file_info(inode, full_path,
&info_buf, xid);
if (rc == 0)
CIFS_I(inode)->cifsAttrs = attrib;

return rc;
}

static int cifs_creation_time_set(unsigned int xid, struct cifs_tcon *pTcon,
struct inode *inode, char *full_path,
const void *value, size_t size)
{
ssize_t rc = -EOPNOTSUPP;
__u64 *pcreation_time = (__u64 *)value;
__u64 creation_time;
FILE_BASIC_INFO info_buf;

if ((value == NULL) || (size != sizeof(__u64)))
return -ERANGE;

memset(&info_buf, 0, sizeof(info_buf));
creation_time = *pcreation_time;
info_buf.CreationTime = cpu_to_le64(creation_time);
if (pTcon->ses->server->ops->set_file_info)
rc = pTcon->ses->server->ops->set_file_info(inode, full_path,
&info_buf, xid);
if (rc == 0)
CIFS_I(inode)->createtime = creation_time;

return rc;
}

static int cifs_xattr_set(const struct xattr_handler *handler,
struct dentry *dentry, struct inode *inode,
Expand Down Expand Up @@ -86,6 +137,23 @@ static int cifs_xattr_set(const struct xattr_handler *handler,

switch (handler->flags) {
case XATTR_USER:
cifs_dbg(FYI, "%s:setting user xattr %s\n", __func__, name);
if ((strcmp(name, CIFS_XATTR_ATTRIB) == 0) ||
(strcmp(name, SMB3_XATTR_ATTRIB) == 0)) {
rc = cifs_attrib_set(xid, pTcon, inode, full_path,
value, size);
if (rc == 0) /* force revalidate of the inode */
CIFS_I(inode)->time = 0;
break;
} else if ((strcmp(name, CIFS_XATTR_CREATETIME) == 0) ||
(strcmp(name, SMB3_XATTR_CREATETIME) == 0)) {
rc = cifs_creation_time_set(xid, pTcon, inode,
full_path, value, size);
if (rc == 0) /* force revalidate of the inode */
CIFS_I(inode)->time = 0;
break;
}

if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto out;

Expand All @@ -95,7 +163,8 @@ static int cifs_xattr_set(const struct xattr_handler *handler,
cifs_sb->local_nls, cifs_sb);
break;

case XATTR_CIFS_ACL: {
case XATTR_CIFS_ACL:
case XATTR_CIFS_NTSD: {
struct cifs_ntsd *pacl;

if (!value)
Expand All @@ -106,12 +175,25 @@ static int cifs_xattr_set(const struct xattr_handler *handler,
} 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
pTcon->ses->server->ops->set_acl) {
rc = 0;
if (handler->flags == XATTR_CIFS_NTSD) {
/* set owner and DACL */
rc = pTcon->ses->server->ops->set_acl(
pacl, size, inode,
full_path,
CIFS_ACL_OWNER);
}
if (rc == 0) {
/* set DACL */
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);
Expand Down Expand Up @@ -179,7 +261,7 @@ static int cifs_creation_time_get(struct dentry *dentry, struct inode *inode,
void *value, size_t size)
{
ssize_t rc;
__u64 * pcreatetime;
__u64 *pcreatetime;

rc = cifs_revalidate_dentry_attr(dentry);
if (rc)
Expand Down Expand Up @@ -244,7 +326,9 @@ static int cifs_xattr_get(const struct xattr_handler *handler,
full_path, name, value, size, cifs_sb);
break;

case XATTR_CIFS_ACL: {
case XATTR_CIFS_ACL:
case XATTR_CIFS_NTSD: {
/* the whole ntsd is fetched regardless */
u32 acllen;
struct cifs_ntsd *pacl;

Expand Down Expand Up @@ -382,6 +466,26 @@ static const struct xattr_handler smb3_acl_xattr_handler = {
.set = cifs_xattr_set,
};

static const struct xattr_handler cifs_cifs_ntsd_xattr_handler = {
.name = CIFS_XATTR_CIFS_NTSD,
.flags = XATTR_CIFS_NTSD,
.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_ntsd_xattr_handler = {
.name = SMB3_XATTR_CIFS_NTSD,
.flags = XATTR_CIFS_NTSD,
.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,
Expand All @@ -401,6 +505,8 @@ const struct xattr_handler *cifs_xattr_handlers[] = {
&cifs_os2_xattr_handler,
&cifs_cifs_acl_xattr_handler,
&smb3_acl_xattr_handler, /* alias for above since avoiding "cifs" */
&cifs_cifs_ntsd_xattr_handler,
&smb3_ntsd_xattr_handler, /* alias for above since avoiding "cifs" */
&cifs_posix_acl_access_xattr_handler,
&cifs_posix_acl_default_xattr_handler,
NULL
Expand Down

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