[refpolicy] [PATCH v2] locallogin: fix the sulogin submodule (emergency shell!)

[dac.override@gmail.com (Dominick Grift)]

On Wed, Apr 26, 2017 at 12:50:02AM +0200, Guido Trentalancia via refpolicy wrote:
> This patch fixes the policy for sulogin. It is very important
> because without this patch, sulogin cannot work properly and
> it should be considered that it is used as an emergency shell
> when there are serious consistency errors in the system, so it
> constitutes the only way to recover the system in such
> circumstances.
> 
> Nowadays, sulogin never uses PAM (at least not the official one
> from util-linux), so obsolete, confusing and buggy policy has
> been removed.
> 
> Extensive testing carried out while creating this patch indicates
> that there aren't other permissions needed to successfully run
> sulogin.
> 
> This second version should apply cleanly to the latest git tree.
> 
> Signed-off-by: Guido Trentalancia <guido@trentalancia.net>
> ---
>  policy/modules/system/locallogin.te |   24 ++++++++++++++----------
>  1 file changed, 14 insertions(+), 10 deletions(-)
> 
> --- a/policy/modules/system/locallogin.te	2017-04-13 22:04:35.111202539 +0200
> +++ b/policy/modules/system/locallogin.te	2017-04-26 00:44:23.028943625 +0200
> @@ -215,7 +215,8 @@ optional_policy(`
>  # Sulogin local policy
>  #
>  
> -allow sulogin_t self:capability dac_override;
> +allow sulogin_t self:capability { dac_override sys_admin sys_tty_config };

I suspect that cap_sys_admin can be safely dontaudited

> +allow sulogin_t self:process setexec;
>  allow sulogin_t self:fd use;
>  allow sulogin_t self:fifo_file rw_fifo_file_perms;
>  allow sulogin_t self:unix_dgram_socket create_socket_perms;
> @@ -228,6 +229,9 @@ allow sulogin_t self:msgq create_msgq_pe
>  allow sulogin_t self:msg { send receive };
>  
>  kernel_read_system_state(sulogin_t)
> +kernel_read_crypto_sysctls(sulogin_t)
> +kernel_stream_connect(sulogin_t)
> +kernel_use_fds(sulogin_t)
>  # because file systems are not mounted:
>  kernel_dontaudit_search_unlabeled(sulogin_t)
>  
> @@ -238,10 +242,13 @@ files_read_etc_files(sulogin_t)
>  
>  auth_read_shadow(sulogin_t)
>  
> +init_getpgid(sulogin_t)
>  init_getpgid_script(sulogin_t)
>  
>  logging_send_syslog_msg(sulogin_t)
>  
> +miscfiles_read_localization(sulogin_t)
> +
>  seutil_read_config(sulogin_t)
>  seutil_read_default_contexts(sulogin_t)
>  
> @@ -252,15 +259,12 @@ userdom_use_user_ptys(sulogin_t)
>  
>  sysadm_shell_domtrans(sulogin_t)
>  
> -# suse and debian do not use pam with sulogin...
> -ifdef(`distro_suse', `define(`sulogin_no_pam')')
> -ifdef(`distro_debian', `define(`sulogin_no_pam')')
> -
> -ifdef(`sulogin_no_pam', `
> -	allow sulogin_t self:capability sys_tty_config;
> -	init_getpgid(sulogin_t)
> -', `
> -	allow sulogin_t self:process setexec;
> +term_use_console(sulogin_t)
> +term_use_unallocated_ttys(sulogin_t)
> +
> +# by default, sulogin does not use pam...
> +# sulogin_pam might need to be defined otherwise
> +ifdef(`sulogin_pam', `
>  	selinux_get_fs_mount(sulogin_t)
>  	selinux_validate_context(sulogin_t)
>  	selinux_compute_access_vector(sulogin_t)
> _______________________________________________
> refpolicy mailing list
> refpolicy at oss.tresys.com
> http://oss.tresys.com/mailman/listinfo/refpolicy

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Dominick Grift
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