[PATCH] Add support for setting owner info, dos attributes, and create time

From: Boris Protopopov
Date: Thu Dec 19 2019 - 11:53:03 EST


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@xxxxxxxxxxx>
---
fs/cifs/xattr.c | 128 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 117 insertions(+), 11 deletions(-)

diff --git a/fs/cifs/xattr.c b/fs/cifs/xattr.c
index 9076150758d8..c41856e6fa22 100644
--- a/fs/cifs/xattr.c
+++ b/fs/cifs/xattr.c
@@ -32,7 +32,8 @@
#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 */
/*
@@ -40,12 +41,62 @@
* 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));
+ info_buf.Attributes = attrib = cpu_to_le32(*pattrib);
+
+ 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));
+ info_buf.CreationTime = creation_time = cpu_to_le64(*pcreation_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,
@@ -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;

@@ -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)
@@ -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);
@@ -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)
@@ -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;

@@ -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,
@@ -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
--
2.14.5