Re: [PATCH v4] secilc/docs: document expandtypeattribute

From: James Carter <jwcart2@gmail.com>
To: Dominick Grift <dominick.grift@defensec.nl>
Cc: SElinux list <selinux@vger.kernel.org>
Subject: Re: [PATCH v4] secilc/docs: document expandtypeattribute
Date: Tue, 4 Aug 2020 10:45:06 -0400	[thread overview]
Message-ID: <CAP+JOzRgJmD8NE-_nY118G_h7B70Y70=jT1n8TimcMGPjDYFxw@mail.gmail.com> (raw)
In-Reply-To: <ypjlft9298vi.fsf@defensec.nl>

On Tue, Aug 4, 2020 at 3:18 AM Dominick Grift
<dominick.grift@defensec.nl> wrote:
>
> James Carter <jwcart2@gmail.com> writes:
>
> > On Sun, Aug 2, 2020 at 8:39 AM Dominick Grift
> > <dominick.grift@defensec.nl> wrote:
> >>
> >> This was added for Androids Treble in 2017.
> >>
> >> Signed-off-by: Dominick Grift <dominick.grift@defensec.nl>
> >> ---
> >> v2: overriden is overridden
> >> v3: add link to README.md
> >> v4: rephrase and add another example
> >>
> >>  secilc/docs/README.md              |  1 +
> >>  secilc/docs/cil_type_statements.md | 44 ++++++++++++++++++++++++++++++
> >>  2 files changed, 45 insertions(+)
> >>
> >> diff --git a/secilc/docs/README.md b/secilc/docs/README.md
> >> index 3f1838e6..efab2a71 100644
> >> --- a/secilc/docs/README.md
> >> +++ b/secilc/docs/README.md
> >> @@ -126,6 +126,7 @@ CIL (Common Intermediate Language)
> >>    * [typealiasactual](cil_type_statements.md#typealiasactual)
> >>    * [typeattribute](cil_type_statements.md#typeattribute)
> >>    * [typeattributeset](cil_type_statements.md#typeattributeset)
> >> +  * [expandtypeattribute](cil_type_statements.md#expandtypeattribute)
> >>    * [typebounds](cil_type_statements.md#typebounds)
> >>    * [typechange](cil_type_statements.md#typechange)
> >>    * [typemember](cil_type_statements.md#typemember)
> >> diff --git a/secilc/docs/cil_type_statements.md b/secilc/docs/cil_type_statements.md
> >> index f9dd3a76..41f0f01a 100644
> >> --- a/secilc/docs/cil_type_statements.md
> >> +++ b/secilc/docs/cil_type_statements.md
> >> @@ -213,6 +213,50 @@ This example is equivalent to `{ domain -kernel.process -ueventd.process -init.p
> >>          )
> >>      )
> >>
> >> +expandtypeattribute
> >> +-------------------
> >> +
> >> +Overrides the compiler defaults for the expansion of one or more previously declared [`typeattribute`](cil_type_statements.md#typeattribute) identifiers.
> >> +
> >> +Note that this statement can be overridden at compile-time with `secilc -X SIZE` and that this functionality is not intended to override `secilc -X SIZE` for individual type attributes!
> >> +
>
> <snip>
> > When the value
> > is false, the type attribute will not be removed from the policy, even
> > if the default expand rules or "-X" option cause the rules involving
> > the type attribute to be expanded.
>
> Yes but I cannot produce that. In my earlier test the type attribute
> was expanded regardless of the -X option.
>
> In my test I instructed secilc to expand all attributes with more than 3
> members (-X 4), then I added a expandtypeattribute statement telling
> secilc to not expand pets and colors.
>
> The result was that it expanded pets and colors anyway.
>

I see the source of your confusion now. "-X 4" means that all
attributes with LESS than 4 types associated with it will be expanded.

Jim

> >
> > Thanks,
> > Jim
> >
> >> +**Statement definition:**
> >> +
> >> +    (expandtypeattribute typeattribute_id true|false)
> >> +
> >> +**Where:**
> >> +
> >> +<table>
> >> +<colgroup>
> >> +<col width="25%" />
> >> +<col width="75%" />
> >> +</colgroup>
> >> +<tbody>
> >> +<tr class="odd">
> >> +<td align="left"><p><code>expandtypeattribute</code></p></td>
> >> +<td align="left"><p>The <code>expandtypeattribute</code> keyword.</p></td>
> >> +</tr>
> >> +<tr class="even">
> >> +<td align="left"><p><code>typeattribute_id</code></p></td>
> >> +<td align="left"><p>One or more previously declared
> >> <code>typeattribute</code> identifiers. Multiple entries consist of
> >> a space separated list enclosed in parentheses '()'.</p></td>
> >> +</tr>
> >> +<tr class="odd">
> >> +<td align="left"><p><code>true | false</code></p></td>
> >> +<td align="left"><p>Either true or false.</p></td>
> >> +</tr>
> >> +</tbody>
> >> +</table>
> >> +
> >> +**Examples:**
> >> +
> >> +This example uses the expandtypeattribute statement to forcibly expand a previously declared `domain` type attribute.
> >> +
> >> +    (expandtypeattribute domain true)
> >> +
> >> +This example uses the expandtypeattribute statement to not expand
> >> previously declared `file_type` and `port_type` type attributes
> >> regardless of compiler defaults.
> >> +
> >> +    (expandtypeattribute (file_type port_type) false)
> >> +
> >>  typebounds
> >>  ----------
> >>
> >> --
> >> 2.28.0
> >>
>
> --
> gpg --locate-keys dominick.grift@defensec.nl
> Key fingerprint = FCD2 3660 5D6B 9D27 7FC6  E0FF DA7E 521F 10F6 4098
> https://sks-keyservers.net/pks/lookup?op=get&search=0xDA7E521F10F64098
> Dominick Grift