90 lines
2.7 KiB
Plaintext
90 lines
2.7 KiB
Plaintext
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=====================================================
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RELOCATING THE CACHE WITH SELINUX ENFORCEMENT ENABLED
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=====================================================
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If the cache is being used on a system on which SELinux is active and running
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in enforcing mode, then the security policy installed by the cachefilesd RPM
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needs to be updated to permit the CacheFiles module and daemon to access the
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cache if the cache is moved.
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The simplest way to do this is to add an auxiliary policy to mark out the
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location of the new cache, whilst leaving the old location still available for
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caching. If anything more is required, then it will be necessary to modify the
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policy that is installed.
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Example sources for the installed policy will be themselves installed by the
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cachefilesd RPM in:
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/usr/share/doc/cachefilesd/
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See the files named:
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cachefilesd.te
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cachefilesd.fc
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cachefilesd.if
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The policy actually used for the defaults, however, is part of the SELinux
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package.
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==========================
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ADDING AN AUXILIARY POLICY
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==========================
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Creating and adding an auxiliary policy is very easy. Follow the following
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steps:
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(0) Check that checkpolicy and selinux-policy* packages are installed. These
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are needed to build your policy.
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(1) Create a new directory and go into it.
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(2) Create a source file to reference the security ID already set up for files
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in the cache as you'll need these to label your own cache directory.
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Assuming you're going to name your policy "mycache", this would have to be
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called "mycache.te":
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[mycache.te]
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policy_module(mycache,1.0.0)
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require { type cachefiles_var_t; }
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(3) Create a source file to note the directory in which you wish your cache to
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reside. This file should be named for your policy, plus a ".fc" suffix:
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[mycache.fc]
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/mycache(/.*)? gen_context(system_u:object_r:cachefiles_var_t,s0)
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This specifies the security ID for the directory in which your cache will
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live and all its descendents. Replace "/mycache" with the path to your
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cache's directory.
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(4) Build the policy:
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make -f /usr/share/selinux/devel/Makefile
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(5) And install it:
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semodule -i mycache.pp
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(6) Create your directory and tell SELinux to label it appropriately:
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mkdir /mycache
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restorecon /mycache
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(7) Check that the directory is labelled appropriately:
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ls -dZ /mycache
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(8) Modify /etc/cachefilesd.conf to point to the correct directory and then
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start the cachefilesd service.
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The auxiliary policy can be later removed by:
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semodule -r mycache.pp
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If the policy is updated, then the version number in policy_module() in
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mycache.te should be increased and the module upgraded:
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semodule -u mycache.pp
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