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<p style="text-align:right;">Last modified: $Date: 2013-03-04 22:48:51 +0900 (Mon, 04 Mar 2013) $</p>
<h1>TOMOYO Linux FAQ</h1>
<hr>
<h2><a name="general">General</a></h2>
<p>Q1: What is TOMOYO Linux?</p>
<p>A1: A Linux kernel that can automatically generate policies for Mandatory Access Control.</p>
<p>Q2: Who are the target users?</p>
<p>A2: Administrators who can't spend their energy for server security managements.</p>
<p>Q3: How much extra memory is consumed?</p>
<p>A3: Fixed part (code and data in the kernel) is about 100 KB, variant part (access permissions) is a few hundred KB.</p>
<p>Q4: How large is the performance loss?</p>
<p>A4: Not tested formally, but users won't recognize.</p>
<p>Q5: Which kernel versions are supported?</p>
<p>A5: 2.4.37 and 2.6.27 to 2.6.31 downloadable from <a href="https://www.kernel.org/">https://www.kernel.org/</a>.</p>
<p>Q6: Is it possible to support patched kernels from distributors?</p>
<p>A6: Yes, if you manually inserts hooks.</p>
<p>Q7: What is the license?</p>
<p>A7: It is GPL.</p>
<p>Q8: Does TOMOYO Linux have any usage other than Mandatory Access Control?</p>
<p>A8: You can create custom filesystem images with minimum files.</p>
<hr>
<h2><a name="management">Policy Management</a></h2>
<p>Q1: Is the policy syntax easy?</p>
<p>A1: Yes, it's very easy.</p>
<p>Q2: What is domain?</p>
<p>A2: The domain in TOMOYO Linux is a history of process execution.</p>
<p>Q3: What is profile?</p>
<p>A3: The profile in TOMOYO Linux is a configuration that defines what kind of MAC to use and what level to apply.</p>
<p>Q4: Can I update policies dynamically?</p>
<p>A4: Yes, but memory used by old policies are not freed.</p>
<p>Q5: Do I need to restart processes after updating policies?</p>
<p>A5: No unless you delete a domain and recreate it.</p>
<p>Q6: Will processes referring old policies crash by updating policies?</p>
<p>A6: No, processes won't crash because the old policies remains in the kernel.</p>
<p>Q7: What measures against tampering policies are there?</p>
<p>A7: Restrict programs or domains that can modify policies.</p>
<p>Q8: How can I edit policies?</p>
<p>A8: CUI editors are included. You may use arbitrary text editors.</p>
<p>Q9: What is "LEARNING mode"?</p>
<p>A9: A mode that access permissions are appended automatically.</p>
<p>Q10: Aren't there problems appending access permissions automatically?</p>
<p>A10: Almost no problem, for TOMOYO Linux uses absolute pathnames and fine-grained domain divisions.</p>
<p>Q11: Can I update packages while the Mandatory Access Control is enabled?</p>
<p>A11: Yes. You can do it by assigning different profiles to domains.</p>
<p>Q12: Can I protect only daemon processes like SELinux's Targeted Policy?</p>
<p>A12: Yes. You can do it by assigning different profiles to domains.</p>
<hr>
<h2><a name="implementation">Implementation</a></h2>
<p>Q1: What is the security model of TOMOYO Linux?</p>
<p>A1: Only DTE.</p>
<p>Q2: Are there concepts of users and roles?</p>
<p>A2: No, but it's possible to delegate a part of administration tasks.</p>
<p>Q3: Are patching to userland applications required?</p>
<p>A3: No.</p>
<p>Q4: TOMOYO Linux can't protect sshd from exploit codes, can it?</p>
<p>A4: No, but it's possible to countermeasure illegal logins by enforcing additional authentication.</p>
<p>Q5: Which division is TOMOYO Linux categorized in TCSEC?</p>
<p>A5: I don't know.</p>
<p>Q6: What security labels does TOMOYO Linux use?</p>
<p>A6: TOMOYO Linux uses absolute pathnames as security labels.</p>
<p>Q7: Can I use wildcards for pathnames?</p>
<p>A7: Yes.</p>
<p>Q8: Is MLS supported?</p>
<p>A8: No. Save in the different directories according to sensitivity level of the file.</p>
<p>Q9: Are there functions like LIDS's stateful ACL?</p>
<p>A9: No.</p>
<p>Q10: Is the correctness of security labels guaranteed?</p>
<p>A10: Since pathnames are used as security labels, the correctness of security labels is guaranteed unless the directory entry get corrupted.</p>
<p>Q11: Are resources other than files are protected?</p>
<p>A11: TOMOYO Linux supports network ports, signal transmissions, capability etc.</p>
<p>Q12: Are device files protected from being tampered with?</p>
<p>A12: You can use tamper-proof /dev filesystem.</p>

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