Re: [PATCH] scaled-back caps, take 4

[Andy Lutomirski <luto@myrealbox.com>]

Chris Wright wrote:
> * Olaf Dietsche (olaf+list.linux-kernel@olafdietsche.de) wrote:
> 
>>Andy Lutomirski <luto@myrealbox.com> writes:
>>
>>
>>>cap_2.6.6-mm2_4.patch: New stripped-back capabilities.
>>>
>>> fs/exec.c               |   15 ++++-
>>> include/linux/binfmts.h |    9 ++-
>>> security/commoncap.c    |  130 ++++++++++++++++++++++++++++++++++++++++++------
>>> 3 files changed, 136 insertions(+), 18 deletions(-)
>>
>>[patch]
>>
>>Why don't you provide this as a configurable andycap.c module?
>>I think, this is the whole point of LSM.
> 
> 
> I agree, if we can't find a clean way to do it.  However, note this
> includes changes to core.  And it's nice to fix this for the base case.

On the other hand, this version has minimal changes to core (it adds a new 
field to linux_binprm and makes fs/exec.c fill in some extra information). 
  These changes shouldn't break any existing code, as the current behavior 
is for bprm->cap_* to be undefined when bprm_set_security is called.  None 
of this is strictly necessary for my patch, but it makes it a lot cleaner.

So, if the core changes were merged, my caps semantics could be maintained 
as a (fairly simple) separate LSM.  That prevents it working with SELinux 
or other (non-stacking) LSMs loaded.

--Andy