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

[Dominick Grift <dominick.grift@defensec.nl>]

James Carter <jwcart2@gmail.com> writes:

> 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.

I think its important to clarify this in the documentation. ie:
expandattribute false will not work if you use -X (-X will override the
false statement)

I think that is unintuitive, I would actually want to be able to for
example expand all attributes with less then 4 members except a few
specific ones.

>
> 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
>> >>
>>
>> --
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>> Dominick Grift

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