Re: [PATCH] libsepol: Fix building Xen policy with devicetreecon

[Steve Lawrence <slawrence@tresys.com>]

On 03/23/2015 11:58 AM, Richard Haines wrote:
> Problems fixed:
> 1) Fix core dump when building CIL policy (corrupted double-linked list)
>    by Steve Lawrence <slawrence@tresys.com>
> 2) Binary policy failed to read with devicetreecon statement.
> 3) Free path name - With a Xen policy running secilc/valgrind
>    there are no memory errors.
> 
> Also added devicetreecon statement to CIL policy.cil and updated the CIL
> Reference Guide.
> 
> Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>

Acked-by: Steve Lawrence <slawrence@tresys.com>

Thanks!

> ---
>  libsepol/cil/docs/cil_xen_statements.xml | 44 ++++++++++++++++++++++++++++++++
>  libsepol/cil/src/cil_build_ast.c         |  2 --
>  libsepol/cil/test/policy.cil             |  1 +
>  libsepol/src/policydb.c                  |  6 +++--
>  4 files changed, 49 insertions(+), 4 deletions(-)
> 
> diff --git a/libsepol/cil/docs/cil_xen_statements.xml b/libsepol/cil/docs/cil_xen_statements.xml
> index 1035b68..c72ef6c 100644
> --- a/libsepol/cil/docs/cil_xen_statements.xml
> +++ b/libsepol/cil/docs/cil_xen_statements.xml
> @@ -3,6 +3,7 @@
>  
>     <sect1>
>        <title>Xen Statements</title>
> +      <para>Policy version 30 introduced the <literal><link linkend="devicetreecon">devicetreecon</link></literal> statement and also expanded the existing I/O memory range to 64 bits in order to support hardware with more than 44 bits of physical address space (32-bit count of 4K pages).</para>
>        <para>See the <ulink url="http://xenbits.xen.org/docs/4.2-testing/misc/xsm-flask.txt">"XSM/FLASK Configuration"</ulink> document for further information (<ulink url="http://xenbits.xen.org/docs/4.2-testing/misc/xsm-flask.txt"></ulink>)</para>
>        <sect2 id="iomemcon">
>           <title>iomemcon</title>
> @@ -180,4 +181,47 @@
>           <programlisting><![CDATA[(pirqcon 33 (unconfined.user object_r unconfined.object low_low))]]></programlisting>
>        </sect2>
>  
> +      <sect2 id="devicetreecon">
> +         <title>devicetreecon</title>
> +         <para>Label device tree nodes.</para>
> +         <para><emphasis role="bold">Statement definition:</emphasis></para>
> +         <programlisting><![CDATA[(devicetreecon path context_id)]]></programlisting>
> +         <para><emphasis role="bold">Where:</emphasis></para>
> +         <informaltable frame="all">
> +            <tgroup cols="2">
> +            <colspec colwidth="2 *"/>
> +            <colspec colwidth="6 *"/>
> +               <tbody>
> +               <row>
> +                  <entry>
> +                     <para><literal>devicetreecon</literal></para>
> +                  </entry>
> +                  <entry>
> +                     <para>The <literal>devicetreecon</literal> keyword.</para>
> +                  </entry>
> +               </row>
> +               <row>
> +                  <entry>
> +                     <para><literal>path</literal></para>
> +                  </entry>
> +                  <entry>
> +                     <para>The device tree path. If this contains spaces enclose within <literal>""</literal>.</para>
> +                  </entry>
> +               </row>
> +               <row>
> +                  <entry>
> +                     <para><literal>context_id</literal></para>
> +                  </entry>
> +                  <entry>
> +                     <para>A previously declared <literal><link linkend="context">context</link></literal> identifier or an anonymous security context (<literal><link linkend="user">user</link> <link linkend="role">role</link> <link linkend="type">type</link> <link linkend="levelrange">levelrange</link></literal>), the range MUST be defined whether the policy is MLS/MCS enabled or not.</para>
> +                  </entry>
> +               </row>
> +            </tbody></tgroup>
> +         </informaltable>
> +
> +         <para><emphasis role="bold">Example:</emphasis></para>
> +         <para>An anonymous context for the specified path:</para>
> +         <programlisting><![CDATA[(devicetreecon "/this is/a/path" (unconfined.user object_r unconfined.object low_low))]]></programlisting>
> +      </sect2>
> +
>     </sect1>
> diff --git a/libsepol/cil/src/cil_build_ast.c b/libsepol/cil/src/cil_build_ast.c
> index 973b2d7..92c3e09 100644
> --- a/libsepol/cil/src/cil_build_ast.c
> +++ b/libsepol/cil/src/cil_build_ast.c
> @@ -4583,8 +4583,6 @@ void cil_destroy_devicetreecon(struct cil_devicetreecon *devicetreecon)
>  		return;
>  	}
>  
> -	free(devicetreecon->path);
> -
>  	if (devicetreecon->context_str == NULL && devicetreecon->context != NULL) {
>  		cil_destroy_context(devicetreecon->context);
>  	}
> diff --git a/libsepol/cil/test/policy.cil b/libsepol/cil/test/policy.cil
> index 9c76cad..25c8545 100644
> --- a/libsepol/cil/test/policy.cil
> +++ b/libsepol/cil/test/policy.cil
> @@ -250,6 +250,7 @@
>  	(iomemcon (0 255) system_u_bin_t_l2h)
>  	(ioportcon (22 22) system_u_bin_t_l2h)
>  	(pcidevicecon 345 system_u_bin_t_l2h)
> +	(devicetreecon "/this is/a/path" system_u_bin_t_l2h)
>  
>  	(constrain (files (read)) (not (or (and (eq t1 exec_t) (eq t2 bin_t)) (eq r1 r2))))
>  	(constrain char_w (not (or (and (eq t1 exec_t) (eq t2 bin_t)) (eq r1 r2))))
> diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c
> index b45b662..d1c0018 100644
> --- a/libsepol/src/policydb.c
> +++ b/libsepol/src/policydb.c
> @@ -1274,7 +1274,7 @@ void ocontext_xen_free(ocontext_t **ocontexts)
>  			c = c->next;
>  			context_destroy(&ctmp->context[0]);
>  			context_destroy(&ctmp->context[1]);
> -			if (i == OCON_ISID)
> +			if (i == OCON_ISID || i == OCON_XEN_DEVICETREE)
>  				free(ctmp->u.name);
>  			free(ctmp);
>  		}
> @@ -2559,11 +2559,13 @@ static int ocontext_read_xen(struct policydb_compat_info *info,
>  				rc = next_entry(buf, fp, sizeof(uint32_t));
>  				if (rc < 0)
>  					return -1;
> -				len = le32_to_cpu(buf[1]);
> +				len = le32_to_cpu(buf[0]);
>  				c->u.name = malloc(len + 1);
>  				if (!c->u.name)
>  					return -1;
>  				rc = next_entry(c->u.name, fp, len);
> +				if (rc < 0)
> +					return -1;
>  				c->u.name[len] = 0;
>  				if (context_read_and_validate
>  				    (&c->context[0], p, fp))
>