ksmbd: fill sids in SMB_FIND_FILE_POSIX_INFO response

This patch fill missing sids in SMB_FIND_FILE_POSIX_INFO response.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/smb2pdu.c

@@ -4722,7 +4722,11 @@ static int find_file_posix_info(struct smb2_query_info_rsp *rsp,
 {
 	struct smb311_posix_qinfo *file_info;
 	struct inode *inode = file_inode(fp->filp);
+	struct user_namespace *user_ns = file_mnt_user_ns(fp->filp);
+	vfsuid_t vfsuid = i_uid_into_vfsuid(user_ns, inode);
+	vfsgid_t vfsgid = i_gid_into_vfsgid(user_ns, inode);
 	u64 time;
+	int out_buf_len = sizeof(struct smb311_posix_qinfo) + 32;
 
 	file_info = (struct smb311_posix_qinfo *)rsp->Buffer;
 	file_info->CreationTime = cpu_to_le64(fp->create_time);
@@ -4739,10 +4743,20 @@ static int find_file_posix_info(struct smb2_query_info_rsp *rsp,
 	file_info->HardLinks = cpu_to_le32(inode->i_nlink);
 	file_info->Mode = cpu_to_le32(inode->i_mode & 0777);
 	file_info->DeviceId = cpu_to_le32(inode->i_rdev);
-	rsp->OutputBufferLength =
-		cpu_to_le32(sizeof(struct smb311_posix_qinfo));
-	inc_rfc1001_len(rsp_org, sizeof(struct smb311_posix_qinfo));
-	return 0;
+
+	/*
+	 * Sids(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, vfsuid_into_kuid(vfsuid)),
+		  SIDUNIX_USER, (struct smb_sid *)&file_info->Sids[0]);
+	id_to_sid(from_kgid_munged(&init_user_ns, vfsgid_into_kgid(vfsgid)),
+		  SIDUNIX_GROUP, (struct smb_sid *)&file_info->Sids[16]);
+
+	rsp->OutputBufferLength = cpu_to_le32(out_buf_len);
+	inc_rfc1001_len(rsp_org, out_buf_len);
+	return out_buf_len;
 }
 
 static int smb2_get_info_file(struct ksmbd_work *work,
@@ -4862,8 +4876,8 @@ static int smb2_get_info_file(struct ksmbd_work *work,
 			pr_err("client doesn't negotiate with SMB3.1.1 POSIX Extensions\n");
 			rc = -EOPNOTSUPP;
 		} else {
-			rc = find_file_posix_info(rsp, fp, work->response_buf);
-			file_infoclass_size = sizeof(struct smb311_posix_qinfo);
+			file_infoclass_size = find_file_posix_info(rsp, fp,
+					work->response_buf);
 		}
 		break;
 	default: