Fork a Process

When a child process is created by fork, its process sets are identical to the parent's process sets. This can be proven by querying the process privilege sets, forking a process, and querying the child process privilege sets:

Parent Process Privilege Sets

Before the fork, the parent process has the following privileges:

Forked Inheritable = proc_setid
Forked Saved = file_setpriv,proc_setid
Forked Permitted = file_setpriv,proc_setid
Forked Effective = none

System Call and Code

pid = fork();
if (pid > 0)
	exit(0);

PRIV_EMPTY(&priv_get);
retval = getppriv(PRIV_INHERITABLE, &priv_get);
printf("retval = %d errno = %d\n", retval, errno);
priv_set_to_str(&priv_get, ',', buffer, &length);
printf("Forked Inheritable = %s\n", buffer);

PRIV_EMPTY(&priv_get);
retval = getppriv(PRIV_SAVED, &priv_get);
printf("retval = %d errno = %d\n", retval, errno);
priv_set_to_str(&priv_get, ',', buffer, &length);
printf("Forked Saved = %s\n", buffer);

PRIV_EMPTY(&priv_get);
retval = getppriv(PRIV_PERMITTED, &priv_get);
printf("retval = %d errno = %d\n", retval, errno);
priv_set_to_str(&priv_get, ',', buffer, &length);
printf("Forked Permitted = %s\n", buffer);

PRIV_EMPTY(&priv_get);
retval = getppriv(PRIV_EFFECTIVE, &priv_get);
printf("retval = %d errno = %d\n", retval, errno);
priv_set_to_str(&priv_get, ',', buffer, &length);
printf("Forked Effective = %s\n", buffer);

New Process Privilege Sets

After the fork(2) system call, the printf statements print the following:

Forked Inheritable = proc_setid
Forked Saved = file_setpriv,proc_setid
Forked Permitted = file_setpriv,proc_setid
Forked Effective = none