lkml.org 
[lkml]   [2012]   [Dec]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] Document how capability bits work
On Fri, Dec 7, 2012 at 5:10 PM, Rob Landley <rob@landley.net> wrote:
> On 12/07/2012 01:32:18 PM, Andy Lutomirski wrote:
>>
>> On Fri, Dec 7, 2012 at 11:21 AM, Serge Hallyn
>> <serge.hallyn@canonical.com> wrote:
>> > Quoting Andy Lutomirski (luto@amacapital.net):
>> >> Signed-off-by: Andy Lutomirski <luto@amacapital.net>
>> >> ---
>> >> Documentation/security/capabilities.txt | 161
>> >> ++++++++++++++++++++++++++++++++
>> >> 1 file changed, 161 insertions(+)
>> >> create mode 100644 Documentation/security/capabilities.txt
>> >
>> > TBH, I think a pointer to the capabilities.7 man page would be better.
>> > (plus, if you feel they are needed, updates to the man page)
>>
>> Updating capabilities.7 wouldn't be a bad idea, but IMO it certainly
>> needs work. For example, it says:
>
> ...
>
>> I would be happy to revise this patch to reference capabilities.7.
>
>
> The capabilities.7 man page is existing maintained documentation on how to
> use this from userspace, which seems to be the point of your document.
> Having include/linux/uapi/capability.h mention its existence might be good.
> Feeding fixes to the documentation we've already got would be good.
>
> I read your document having largely ignored capabilities for years, and
> don't feel I have a better understanding of them after reading it. (I'm
> aware they exist, I'm aware they're used as a justification for extended
> attributes, I'm aware people think breaking a fireplace into a bunch of
> candleflames increases fire safety. I'm aware of
> http://forums.grsecurity.net/viewtopic.php?f=7&t=2522 and I _used_ to be
> aware of
> http://userweb.kernel.org/~morgan/sendmail-capabilities-war-story.html but
> kernel.org never bothered putting most of itself back together after the
> breakin last year and archive.org doesn't have a copy. I'm aware that a
> decade ago at Atlanta Linux Showcase in california Ted Tso was sad nobody
> was using them yet. But I haven't hugely been tracking changes over the last
> 5 years in how they work. It looks like figuring out who has what involves
> working through exercises in set theory that cannot be explained using a 127
> bit ascii set. Personally, I prefer "more dangerous" security setups that
> don't require I pull out scratch paper to reason about the state of the
> system, so perhaps I'm biased here.)

Heh. I agree this stuff is shockingly complicated. (And this
document isn't wriiten in ASCII...)

I actually wrote this file because I was reading the code and trying
to figure out wtf was going on. This is the result :) I'll see if I
can improve capabilities.7.

Any pointers to things you wanted to understand?

--Andy


\
 
 \ /
  Last update: 2012-12-08 02:41    [W:0.059 / U:2.508 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site