ksmbd: change security id to the one samba used for posix extension

Samba set SIDOWNER and SIDUNIX_GROUP in create posix context and
set SIDUNIX_USER/GROUP in other sids for posix extension.
This patch change security id to the one samba used.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/oplock.c

@@ -1616,7 +1616,11 @@ void create_posix_rsp_buf(char *cc, struct ksmbd_file *fp)
 	memset(buf, 0, sizeof(struct create_posix_rsp));
 	buf->ccontext.DataOffset = cpu_to_le16(offsetof
 			(struct create_posix_rsp, nlink));
-	buf->ccontext.DataLength = cpu_to_le32(52);
+	/*
+	 * DataLength = nlink(4) + reparse_tag(4) + mode(4) +
+	 * domain sid(28) + unix group sid(16).
+	 */
+	buf->ccontext.DataLength = cpu_to_le32(56);
 	buf->ccontext.NameOffset = cpu_to_le16(offsetof
 			(struct create_posix_rsp, Name));
 	buf->ccontext.NameLength = cpu_to_le16(POSIX_CTXT_DATA_LEN);
@@ -1641,10 +1645,17 @@ void create_posix_rsp_buf(char *cc, struct ksmbd_file *fp)
 	buf->nlink = cpu_to_le32(inode->i_nlink);
 	buf->reparse_tag = cpu_to_le32(fp->volatile_id);
 	buf->mode = cpu_to_le32(inode->i_mode);
+	/*
+	 * SidBuffer(44) contain two sids(Domain sid(28), UNIX group sid(16)).
+	 * Domain sid(28) = revision(1) + num_subauth(1) + authority(6) +
+	 *		    sub_auth(4 * 4(num_subauth)) + RID(4).
+	 * UNIX group id(16) = revision(1) + num_subauth(1) + authority(6) +
+	 *		       sub_auth(4 * 1(num_subauth)) + RID(4).
+	 */
 	id_to_sid(from_kuid_munged(&init_user_ns, vfsuid_into_kuid(vfsuid)),
-		  SIDNFS_USER, (struct smb_sid *)&buf->SidBuffer[0]);
+		  SIDOWNER, (struct smb_sid *)&buf->SidBuffer[0]);
 	id_to_sid(from_kgid_munged(&init_user_ns, vfsgid_into_kgid(vfsgid)),
-		  SIDNFS_GROUP, (struct smb_sid *)&buf->SidBuffer[20]);
+		  SIDUNIX_GROUP, (struct smb_sid *)&buf->SidBuffer[28]);
 }
 
 /*

fs/ksmbd/smb2pdu.c

@@ -3572,10 +3572,15 @@ static int smb2_populate_readdir_entry(struct ksmbd_conn *conn, int info_level,
 				FILE_ATTRIBUTE_DIRECTORY_LE : FILE_ATTRIBUTE_ARCHIVE_LE;
 		if (d_info->hide_dot_file && d_info->name[0] == '.')
 			posix_info->DosAttributes |= FILE_ATTRIBUTE_HIDDEN_LE;
+		/*
+		 * SidBuffer(32) contain two sids(Domain sid(16), UNIX group sid(16)).
+		 * UNIX sid(16) = revision(1) + num_subauth(1) + authority(6) +
+		 *		  sub_auth(4 * 1(num_subauth)) + RID(4).
+		 */
 		id_to_sid(from_kuid_munged(&init_user_ns, ksmbd_kstat->kstat->uid),
-			  SIDNFS_USER, (struct smb_sid *)&posix_info->SidBuffer[0]);
+			  SIDUNIX_USER, (struct smb_sid *)&posix_info->SidBuffer[0]);
 		id_to_sid(from_kgid_munged(&init_user_ns, ksmbd_kstat->kstat->gid),
-			  SIDNFS_GROUP, (struct smb_sid *)&posix_info->SidBuffer[20]);
+			  SIDUNIX_GROUP, (struct smb_sid *)&posix_info->SidBuffer[16]);
 		memcpy(posix_info->name, conv_name, conv_len);
 		posix_info->name_len = cpu_to_le32(conv_len);
 		posix_info->NextEntryOffset = cpu_to_le32(next_entry_offset);

fs/ksmbd/smb2pdu.h

@@ -158,7 +158,8 @@ struct create_posix_rsp {
 	__le32 nlink;
 	__le32 reparse_tag;
 	__le32 mode;
-	u8 SidBuffer[40];
+	/* SidBuffer contain two sids(Domain sid(28), UNIX group sid(16)) */
+	u8 SidBuffer[44];
 } __packed;
 
 struct smb2_buffer_desc_v1 {
@@ -439,7 +440,8 @@ struct smb2_posix_info {
 	__le32 HardLinks;
 	__le32 ReparseTag;
 	__le32 Mode;
-	u8 SidBuffer[40];
+	/* SidBuffer contain two sids (UNIX user sid(16), UNIX group sid(16)) */
+	u8 SidBuffer[32];
 	__le32 name_len;
 	u8 name[1];
 	/*