selinux/secilc/docs/cil_container_statements.md

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Container Statements
====================
block
-----
Start a new namespace.
Not allowed in [`macro`](cil_call_macro_statements.md#macro) and [`optional`](cil_container_statements.md#optional) blocks.
[`sensitivity`](cil_mls_labeling_statements.md#sensitivity) and [`category`](cil_mls_labeling_statements.md#category) statements are not allowed in [`block`](cil_container_statements.md#block) blocks.
**Statement definition:**
```secil
(block block_id
cil_statement
...
)
```
**Where:**
<table>
<colgroup>
<col width="25%" />
<col width="75%" />
</colgroup>
<tbody>
<tr class="odd">
<td align="left"><p><code>block</code></p></td>
<td align="left"><p>The <code>block</code> keyword.</p></td>
</tr>
<tr class="even">
<td align="left"><p><code>block_id</code></p></td>
<td align="left"><p>The namespace identifier.</p></td>
</tr>
<tr class="odd">
<td align="left"><p><code>cil_statement</code></p></td>
<td align="left"><p>Zero or more valid CIL statements.</p></td>
</tr>
</tbody>
</table>
**Example:**
See the [`blockinherit`](cil_container_statements.md#blockinherit) statement for an example.
blockabstract
-------------
Declares the namespace as a 'template' and does not generate code until instantiated by another namespace that has a [`blockinherit`](cil_container_statements.md#blockinherit) statement.
Not allowed in [`macro`](cil_call_macro_statements.md#macro) and [`optional`](cil_container_statements.md#optional) blocks.
**Statement definition:**
```secil
(block block_id
(blockabstract template_id)
cil_statement
...
)
```
**Where:**
<table>
<colgroup>
<col width="25%" />
<col width="75%" />
</colgroup>
<tbody>
<tr class="odd">
<td align="left"><p><code>block</code></p></td>
<td align="left"><p>The <code>block</code> keyword.</p></td>
</tr>
<tr class="even">
<td align="left"><p><code>block_id</code></p></td>
<td align="left"><p>The namespace identifier.</p></td>
</tr>
<tr class="odd">
<td align="left"><p><code>blockabstract</code></p></td>
<td align="left"><p>The <code>blockabstract</code> keyword.</p></td>
</tr>
<tr class="even">
<td align="left"><p><code>template_id</code></p></td>
<td align="left"><p>The abstract namespace identifier. This must match the <code>block_id</code> entry.</p></td>
</tr>
<tr class="odd">
<td align="left"><p><code>cil_statement</code></p></td>
<td align="left"><p>Zero or more valid CIL statements forming the abstract block.</p></td>
</tr>
</tbody>
</table>
**Example:**
See the [`blockinherit`](cil_container_statements.md#blockinherit) statement for an example.
blockinherit
------------
Used to add common policy rules to the current namespace via a template that has been defined with the [`blockabstract`](cil_container_statements.md#blockabstract) statement. All [`blockinherit`](cil_container_statements.md#blockinherit) statements are resolved first and then the contents of the block are copied. This is so that inherited blocks will not be inherited. For a concrete example, please see the examples section.
Inherited rules are resolved by searching namespaces in the following order:
- The parent namespaces (if any) where the [`blockinherit`](cil_container_statements.md#blockinherit) rule is located with the exception of the global namespace.
- The parent namespaces of the block being inherited (but not that block's namespace) with the exception of the global namespace.
- The global namespace.
Not allowed in [`macro`](cil_call_macro_statements.md#macro) blocks.
**Statement definition:**
```secil
(block block_id
(blockinherit template_id)
cil_statement
...
)
```
**Where:**
<table>
<colgroup>
<col width="25%" />
<col width="75%" />
</colgroup>
<tbody>
<tr class="odd">
<td align="left"><p><code>block</code></p></td>
<td align="left"><p>The <code>block</code> keyword.</p></td>
</tr>
<tr class="even">
<td align="left"><p><code>block_id</code></p></td>
<td align="left"><p>The namespace identifier.</p></td>
</tr>
<tr class="odd">
<td align="left"><p><code>blockinherit</code></p></td>
<td align="left"><p>The <code>blockinherit</code> keyword.</p></td>
</tr>
<tr class="even">
<td align="left"><p><code>template_id</code></p></td>
<td align="left"><p>The inherited namespace identifier.</p></td>
</tr>
<tr class="odd">
<td align="left"><p><code>cil_statement</code></p></td>
<td align="left"><p>Zero or more valid CIL statements.</p></td>
</tr>
</tbody>
</table>
**Example:**
This example contains a template `client_server` that is instantiated in two blocks (`netserver_app` and `netclient_app`):
```secil
; This is the template block:
(block client_server
(blockabstract client_server)
; Log file labeling
(type log_file)
(typeattributeset file_type (log_file))
(typeattributeset data_file_type (log_file))
(allow process log_file (dir (write search create setattr add_name)))
(allow process log_file (file (create open append getattr setattr)))
(roletype object_r log_file)
(context log_file_context (u object_r log_file low_low))
; Process labeling
(type process)
(typeattributeset domain (process))
(call app_domain (process))
(call net_domain (process))
)
; This is a policy block that will inherit the abstract block above:
(block netclient_app
; Add common policy rules to namespace:
(blockinherit client_server)
; Label the log files
(filecon "/data/data/com.se4android.netclient/.*" file log_file_context)
)
; This is another policy block that will inherit the abstract block above:
(block netserver_app
; Add common policy rules to namespace:
(blockinherit client_server)
; Label the log files
(filecon "/data/data/com.se4android.netserver/.*" file log_file_context)
)
; This is an example of how blockinherits resolve inherits before copying
(block a
(type one))
(block b
; Notice that block a is declared here as well
(block a
(type two)))
; This will first copy the contents of block b, which results in type b.a.two being copied.
; Next, the contents of block a will be copied which will result in type a.one.
(block ab
(blockinherit b)
(blockinherit a))
```
optional
--------
Declare an [`optional`](cil_container_statements.md#optional) namespace. All CIL statements in the optional block must be satisfied before instantiation in the binary policy.
Not allowed in [`booleanif`](cil_conditional_statements.md#booleanif) blocks.
[`tunable`](cil_conditional_statements.md#tunable), [`in`](cil_container_statements.md#in), [`block`](cil_container_statements.md#block), [`blockabstract`](cil_container_statements.md#blockabstract), and [`macro`](cil_call_macro_statements.md#macro) statements are not allowed in [`optional`](cil_container_statements.md#optional) blocks.
**Statement definition:**
```secil
(optional optional_id
cil_statement
...
)
```
**Where:**
<table>
<colgroup>
<col width="25%" />
<col width="75%" />
</colgroup>
<tbody>
<tr class="odd">
<td align="left"><p><code>optional</code></p></td>
<td align="left"><p>The <code>optional</code> keyword.</p></td>
</tr>
<tr class="even">
<td align="left"><p><code>optional_id</code></p></td>
<td align="left"><p>The <code>optional</code> namespace identifier.</p></td>
</tr>
<tr class="odd">
<td align="left"><p><code>cil_statement</code></p></td>
<td align="left"><p>Zero or more valid CIL statements.</p></td>
</tr>
</tbody>
</table>
**Example:**
This example will instantiate the optional block `ext_gateway.move_file` into policy providing all optional CIL statements can be resolved:
```secil
(block ext_gateway
......
(optional move_file
(typetransition process msg_filter.move_file.in_queue file msg_filter.move_file.in_file)
(allow process msg_filter.move_file.in_queue (dir (read getattr write search add_name)))
(allow process msg_filter.move_file.in_file (file (write create getattr)))
(allow msg_filter.move_file.in_file unconfined.object (filesystem (associate)))
(typetransition msg_filter.int_gateway.process msg_filter.move_file.out_queue file
msg_filter.move_file.out_file)
(allow msg_filter.int_gateway.process msg_filter.move_file.out_queue (dir (read write search)))
(allow msg_filter.int_gateway.process msg_filter.move_file.out_file (file (read getattr unlink)))
) ; End optional block
.....
) ; End block
```
in
--
Allows the insertion of CIL statements into a named container ([`block`](cil_container_statements.md#block), [`optional`](cil_container_statements.md#optional) or [`macro`](cil_call_macro_statements.md#macro)).
Not allowed in [`macro`](cil_call_macro_statements.md#macro), [`booleanif`](cil_conditional_statements.md#booleanif), and other [`in`](cil_container_statements.md#in) blocks.
[`tunable`](cil_conditional_statements.md#tunable) and [`in`](cil_container_statements.md#in) statements are not allowed in [`in`](cil_container_statements.md#in) blocks.
**Statement definition:**
```secil
(in container_id
cil_statement
...
)
```
**Where:**
<table>
<colgroup>
<col width="25%" />
<col width="75%" />
</colgroup>
<tbody>
<tr class="odd">
<td align="left"><p><code>in</code></p></td>
<td align="left"><p>The <code>in</code> keyword.</p></td>
</tr>
<tr class="even">
<td align="left"><p><code>container_id</code></p></td>
<td align="left"><p>A valid <code>block</code>, <code>optional</code> or <code>macro</code> namespace identifier.</p></td>
</tr>
<tr class="odd">
<td align="left"><p><code>cil_statement</code></p></td>
<td align="left"><p>Zero or more valid CIL statements.</p></td>
</tr>
</tbody>
</table>
**Example:**
This will add rules to the container named `system_server`:
```secil
(in system_server
(dontaudit process secmark_demo.dns_packet (packet (send recv)))
(allow process secmark_demo.dns_packet (packet (send recv)))
)
```