From: pebenito@ieee.org (Chris PeBenito)
Date: Tue, 27 Dec 2016 10:53:10 -0500
Subject: [refpolicy] [PATCH] bootloader: stricter permissions and more
 tailored file contexts
In-Reply-To: <1482452559.20547.19.camel@trentalancia.net>
References: <1482452559.20547.19.camel@trentalancia.net>
Message-ID: <2e06af30-e415-2fb6-92ac-0cccd9332fa0@ieee.org>
To: refpolicy@oss.tresys.com
List-Id: refpolicy.oss.tresys.com

On 12/22/16 19:22, Guido Trentalancia via refpolicy wrote:
> Update the bootloader module so that it can manage only its
> own runtime files and not all boot_t files (which include,
> for example, the common locations for kernel images and
> initramfs archives) and so that it can execute only its own
> etc files (needed by grub2-mkconfig) and not all etc_t files
> which is more dangerous.

Merged.


> Signed-off-by: Guido Trentalancia <guido@trentalancia.net>
> ---
>  policy/modules/admin/bootloader.fc |    6 ++++++
>  policy/modules/admin/bootloader.te |   17 +++++++++++++----
>  2 files changed, 19 insertions(+), 4 deletions(-)
>
> diff -pru a/policy/modules/admin/bootloader.fc b/policy/modules/admin/bootloader.fc
> --- a/policy/modules/admin/bootloader.fc	2016-08-06 21:26:43.273774031 +0200
> +++ b/policy/modules/admin/bootloader.fc	2016-12-23 01:10:37.258482434 +0100
> @@ -1,6 +1,12 @@
> +/boot/grub.*	-d	gen_context(system_u:object_r:bootloader_run_t,s0)
> +/boot/grub.*/.*		gen_context(system_u:object_r:bootloader_run_t,s0)
> +
> +/boot/grub.*/grub.cfg	--	gen_context(system_u:object_r:bootloader_etc_t,s0)
> +/boot/grub.*/grub.conf	--	gen_context(system_u:object_r:bootloader_etc_t,s0)
>
>  /etc/lilo\.conf.*	--	gen_context(system_u:object_r:bootloader_etc_t,s0)
>  /etc/yaboot\.conf.*	--	gen_context(system_u:object_r:bootloader_etc_t,s0)
> +/etc/grub.d(/.*)?	--	gen_context(system_u:object_r:bootloader_etc_t,s0)
>
>  /sbin/grub		--	gen_context(system_u:object_r:bootloader_exec_t,s0)
>  /sbin/lilo.*		--	gen_context(system_u:object_r:bootloader_exec_t,s0)
> diff -pru a/policy/modules/admin/bootloader.te b/policy/modules/admin/bootloader.te
> --- a/policy/modules/admin/bootloader.te	2016-08-06 21:26:43.274774043 +0200
> +++ b/policy/modules/admin/bootloader.te	2016-12-23 01:17:00.900143820 +0100
> @@ -22,6 +22,13 @@ application_domain(bootloader_t, bootloa
>  role bootloader_roles types bootloader_t;
>
>  #
> +# bootloader_run_t are image and other runtime
> +# files
> +#
> +type bootloader_run_t alias run_bootloader_t;
> +files_type(bootloader_run_t)
> +
> +#
>  # bootloader_etc_t is the configuration file,
>  # grub.conf, lilo.conf, etc.
>  #
> @@ -45,7 +52,7 @@ allow bootloader_t self:capability { dac
>  allow bootloader_t self:process { signal_perms execmem };
>  allow bootloader_t self:fifo_file rw_fifo_file_perms;
>
> -allow bootloader_t bootloader_etc_t:file read_file_perms;
> +allow bootloader_t bootloader_etc_t:file exec_file_perms;
>  # uncomment the following lines if you use "lilo -p"
>  #allow bootloader_t bootloader_etc_t:file manage_file_perms;
>  #files_etc_filetrans(bootloader_t,bootloader_etc_t,file)
> @@ -59,6 +66,11 @@ files_tmp_filetrans(bootloader_t, bootlo
>  # for tune2fs (cjp: ?)
>  files_root_filetrans(bootloader_t, bootloader_tmp_t, file)
>
> +manage_dirs_pattern(bootloader_t, bootloader_run_t, bootloader_run_t)
> +manage_files_pattern(bootloader_t, bootloader_run_t, bootloader_run_t)
> +manage_lnk_files_pattern(bootloader_t, bootloader_run_t, bootloader_run_t)
> +files_boot_filetrans(bootloader_t, bootloader_run_t, { dir file lnk_file })
> +
>  kernel_getattr_core_if(bootloader_t)
>  kernel_read_network_state(bootloader_t)
>  kernel_read_system_state(bootloader_t)
> @@ -96,10 +108,7 @@ corecmd_exec_all_executables(bootloader_
>  domain_use_interactive_fds(bootloader_t)
>
>  files_create_boot_dirs(bootloader_t)
> -files_manage_boot_files(bootloader_t)
> -files_manage_boot_symlinks(bootloader_t)
>  files_read_etc_files(bootloader_t)
> -files_exec_etc_files(bootloader_t)
>  files_read_usr_src_files(bootloader_t)
>  files_read_usr_files(bootloader_t)
>  files_read_var_files(bootloader_t)

-- 
Chris PeBenito