Re: [PATCH] capabilities: Ambient capability set V2

From: Christoph Lameter
Date: Mon Mar 02 2015 - 10:43:29 EST


On Sat, 28 Feb 2015, Serge E. Hallyn wrote:

> Your example program is not filling in pI though?

The setcap sets the inheritance bit. When the binary runs the i bits
should be set.

> Ah, i see why. In get_file_caps() you are still assigning
>
> fP = pA
>
> if the file has no file capabilities. so then you are actually
> doing
>
> pP' = (X & (fP | pA)) | (pI & (fI | pA))
> rather than
> pP' = (X & fP) | (pI & (fI | pA))


I thought that fP, fI and pI = {} since the file has no caps
so this comes out as

pP' = pA

> Other than that, the patch is looking good to me. We should
> consider emitting an audit record when a task fills in its

How do I do that?

> pA, and I do still wonder whether we should be requiring
> CAP_SETFCAP (unsure how best to think of it). But assuming the
> fP = pA was not intended, I think this largely does the right
> thing.
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