Write to the File

The Secret process opens somefile for writing in the Confidential /export/home/heartyann single-level directory, performs a write operation, and closes the file.

filedes = open("/export/home/.MLD.heartyann/.SLD.1/somefile", O_WRONLY);
size = write(filedes, buffer, 14);
retval = close(filedes);

• Mandatory access checks on the open(2) system call - The process needs mandatory search access to /export/home/heartyann, and mandatory write access to somefile. The process running at Secret passes the mandatory search access check, but does not pass the mandatory write access check. For mandatory write access, somefile's sensitivity label must dominate the process sensitivity label and it does not (Confidential does not dominate Secret). The process can assert the file_mac_write privilege to override this restriction or assert an error.

• Discretionary access checks on the open(2) system call - The process needs discretionary search access to /export/home/heartyann, and discretionary write access to somefile. The permission bits for other on the directory path and somefile allow the discretionary search access, but do not pass the discretionary write access check. The process can assert the file_dac_write privilege to override this restriction or assert an error.

• Mandatory access checks on the write(2) system call - The mandatory access checks were performed when somefile opened. No other access checks are performed.

• Discretionary access checks on the write(2) system call - The discretionary access checks were performed when somefile was opened. No other access checks are performed.