Add SMB 2 support for getting and setting SACLs

Fix passing of the additional security info via version
operations. Force new open when getting SACL and avoid
reuse of files that were previously open without
sufficient privileges to access SACLs.
Signed-off-by: Boris Protopopov <pboris@amazon.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb2ops.c

@@ -3369,9 +3369,9 @@ get_smb2_acl(struct cifs_sb_info *cifs_sb,
 	struct cifs_ntsd *pntsd = NULL;
 	struct cifsFileInfo *open_file = NULL;
 
-	if (inode)
+	if (inode && !(info & SACL_SECINFO))
 		open_file = find_readable_file(CIFS_I(inode), true);
-	if (!open_file)
+	if (!open_file || (info & SACL_SECINFO))
 		return get_smb2_acl_by_path(cifs_sb, path, pacllen, info);
 
 	pntsd = get_smb2_acl_by_fid(cifs_sb, &open_file->fid, pacllen, info);

fs/cifs/smb2pdu.c

@@ -3480,8 +3480,10 @@ SMB311_posix_query_info(const unsigned int xid, struct cifs_tcon *tcon,
 int
 SMB2_query_acl(const unsigned int xid, struct cifs_tcon *tcon,
 	       u64 persistent_fid, u64 volatile_fid,
-	       void **data, u32 *plen, u32 additional_info)
+	       void **data, u32 *plen, u32 extra_info)
 {
+	__u32 additional_info = OWNER_SECINFO | GROUP_SECINFO | DACL_SECINFO |
+				extra_info;
 	*plen = 0;
 
 	return query_info(xid, tcon, persistent_fid, volatile_fid,

fs/cifs/xattr.c

@@ -340,21 +340,19 @@ static int cifs_xattr_get(const struct xattr_handler *handler,
 		 * fetch owner, DACL, and SACL if asked for full descriptor,
 		 * fetch owner and DACL otherwise
 		 */
-		u32 acllen, additional_info = 0;
+		u32 acllen, extra_info;
 		struct cifs_ntsd *pacl;
 
 		if (pTcon->ses->server->ops->get_acl == NULL)
 			goto out; /* rc already EOPNOTSUPP */
 
 		if (handler->flags == XATTR_CIFS_NTSD_FULL) {
-			additional_info = OWNER_SECINFO | GROUP_SECINFO |
-				DACL_SECINFO | SACL_SECINFO;
+			extra_info = SACL_SECINFO;
 		} else {
-			additional_info = OWNER_SECINFO | GROUP_SECINFO |
-				DACL_SECINFO;
+			extra_info = 0;
 		}
 		pacl = pTcon->ses->server->ops->get_acl(cifs_sb,
-				inode, full_path, &acllen, additional_info);
+				inode, full_path, &acllen, extra_info);
 		if (IS_ERR(pacl)) {
 			rc = PTR_ERR(pacl);
 			cifs_dbg(VFS, "%s: error %zd getting sec desc\n",