Re: "netstat -Z" reimplementation

[Eric Paris <eparis@redhat.com>]

On 07/27/2011 08:09 AM, Stephen Smalley wrote:
> On Wed, 2011-07-27 at 17:28 +0800, Rongqing Li wrote:
>> SELinux folks, Stephen:
>>
>> I have some thoughts about reimplementation of 'netstat -Z', but I do
>> not know if it is valuable, or if there are other risks. Could you
>> evaluate my implementation, or give me your valuable advice?
>>
>> 1. From kernel, print the socket labels to tcp, udp, raw, unix
>> files under /proc/net/.
>>
>> Now the /proc/net/tcp /proc/net/udp ... include many socket's
>> information, like local address, remote address, inode, I think we can
>> put the socket's security context to these files.
>>
>> To avoid to expose these information to non-privileged users, security
>> checking should be done when expose the socket security context to procfs.
> 
> We can already control the ability to read /proc/net files by labeling
> them via genfscon statements and then writing policy accordingly.  Do we
> think exposing the (raw) security context is any more of a concern than
> the rest of the information in the file?
> 
> Can we add a field to those files without breaking compatibility with
> existing userspace?

I tried once in the past and was told that no, I was not allowed to add
fields (seemed pretty stupid to me at the time and I don't remember if
the person who told me that actually knew what they were talking about)

I believe I was told (and you should believe that my memory for things
more than 10 minutes old stinks and this was about 4 years ago) that I
was supposed to use "tcp_diag" instead.  I never figured out what that
was, so I never got the patch in...

Just figured you should know up front....

-Eric



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