Re: audit2allow help to allow, but how to disallow

[Bhuvan Gupta <bhuvangu@xxxxxxxxx>]

Hello,

I am working with selinux sandbox "http://danwalsh.livejournal.com/28545.html".

Blog clearing mentions that the sandbox "Can not Open or Create any files on the system " except the the shared libraries.

But current sandbox allow to read dir stuff which i think should not be allowed:

currently i can successfully ran:
"sandbox ls /usr"

ls -Z for my /usr is:
drwxr-xr-x. root root system_u:object_r:usr_t:s0       usr

Now i used sesearch based policy analysis tool to find the allow rules and i have listed few which i can understand and think should not be there:
[1] allow sandbox_domain default_t : file { ioctl read write getattr lock append } ;   # sandbox_t is allow to read write to file having type as default_t, but it doesnt allow to open it..so whats the significance of {read write}
[2] allow domain usr_t : dir { ioctl read getattr lock search open }

Added my system details and here is the list of allowed rules "https://docs.google.com/document/d/1fwNXcaKUuYthiK_qEYuaZHuTzAnCTlMnWF713RgblVk/edit?usp=sharing"

I have started with selinux about 1 week back so there might be problem with my thinking model.

Does the above stuff make sense from logical point of view and should fixed ?

Initially i thought that i will just disallow what i dont want...but know i have realised that selinux is denial by default model and we can only allow stuff.

>>yum list installed | grep selinux
libselinux.x86_64                      2.2.2-6.el7             
libselinux-python.x86_64               2.2.2-6.el7            
libselinux-utils.x86_64                2.2.2-6.el7               
selinux-policy.noarch                  3.12.1-153.el7_0.13       
selinux-policy-devel.noarch            3.12.1-153.el7_0.13       
selinux-policy-sandbox.noarch          3.12.1-153.el7_0.13     
selinux-policy-targeted.noarch         3.12.1-153.el7_0.13               

>> yum list installed | grep sandbox
selinux-policy-sandbox.noarch          3.12.1-153.el7_0.13

Thanks

Thanks

On Tue, Jan 20, 2015 at 2:36 AM, Daniel J Walsh <dwalsh@xxxxxxxxxx> wrote:

What do you want to Disallow?

On 01/18/2015 06:34 AM, Bhuvan Gupta wrote:

Hello,

"Audit2allow" can add rule to allow some operation.

But let say we want to disallow some operation which is allowed by some policy module. let say open operation on some files.

Is there a easy way to achieve that ?

Or i do have to:

[1] get the policy source.

[2] edit it accordingly 

[3] build and reinstall the policy.

Thanks

Bhuvan

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