Re: [PATCH 10/10] MLSXFRM-v02: Auto-labeling of child sockets

[Paul Moore <paul.moore@hp.com>]

Venkat Yekkirala wrote:
>>Hmmm.  I think we are having a bit of a disconnect here, 
>>perhaps I'm not
>>explaining myself very clearly so let me give it another shot.
>>
>>Please look at net/socket.c:sys_accept() and pay attention to what
>>happens to the child socket 'newsock' ...
>>
>> 1. The child 'newsock', 'struct socket' type, is allocated 
>>by a call to
>>    sock_alloc()
>> 2. 'newsock' inherits it's 'type' and 'ops' fields from it's parent,
>>    'struct socket' socket, 'sock'
>> 3. A new file descriptior is allocated for 'newsock', the file
>>    descriptior is called 'newfd'
>> 4. 'newfd' is associated with 'newsock'
>> 5. 'security_socket_accept()' is called
>> 6. ...
>>
>>Unless I'm mistaken, nowhere in the first four steps does the
>>'newsock->sk' field get populated by a 'struct sock *' from the accept
>>queue of 'sock'.  The result is that when
>>'{security,selinux}_socket_accept()' is called the child's 
>>'sk' field is
>>not yet valid meaning the inode associated with the child's 
>>socket will
>>be labeled with the parent socket's SID.
> 
> The sequence you mention is 100% correct. But you need to look past the
> above.
> Like I mentioned yesterday, this sid is replaced with the one from the
> child "sock" in selinux_sock_graft().

Thanks, that is what I was missing.  I misunderstood your comment
yesterday about sock_graft().  Sorry for the confusion on my part.

-- 
paul moore
linux security @ hp

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