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Message-ID: <919b8210-aa05-645f-2d01-7f83541c1b2a@ieee.org>
Date:   Wed, 27 Oct 2021 09:11:18 -0400
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Subject: Re: [PATCH] patch for sddm with PAM
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To:     Russell Coker <russell@coker.com.au>,
        selinux-refpolicy@vger.kernel.org
References: <YWFmepZr5qvuNUVZ@xev.coker.com.au>
From:   Chris PeBenito <pebenito@ieee.org>
In-Reply-To: <YWFmepZr5qvuNUVZ@xev.coker.com.au>
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On 10/9/21 05:52, Russell Coker wrote:
> This patch makes the recent versions of sddm work for X logins.  Sddm uses
> PAM to start the actual XDM under a different UID so we have to work with
> this.
> 
> Signed-off-by: Russell Coker <russell@coker.com.au>
> 
> Index: refpolicy-2.20210908/policy/modules/services/xserver.te
> ===================================================================
> --- refpolicy-2.20210908.orig/policy/modules/services/xserver.te
> +++ refpolicy-2.20210908/policy/modules/services/xserver.te
> @@ -18,6 +18,7 @@ gen_require(`
>   	class x_resource all_x_resource_perms;
>   	class x_event all_x_event_perms;
>   	class x_synthetic_event all_x_synthetic_event_perms;
> +	role xdm_r;
>   ')
>   
>   ########################################
> @@ -152,6 +153,10 @@ init_daemon_domain(xdm_t, xdm_exec_t)
>   xserver_object_types_template(xdm)
>   xserver_common_x_domain_template(xdm, xdm_t)
>   
> +# for sddm to use pam for greeter
> +role xdm_r types xdm_t;
> +allow system_r xdm_r;
> +
>   type xdm_lock_t;
>   files_lock_file(xdm_lock_t)
>   
> @@ -848,6 +853,9 @@ manage_files_pattern(xserver_t, xdm_tmp_
>   manage_lnk_files_pattern(xserver_t, xdm_tmp_t, xdm_tmp_t)
>   manage_sock_files_pattern(xserver_t, xdm_tmp_t, xdm_tmp_t)
>   
> +# for sddm to use pam for greeter, sddm greeter needs execmod
> +allow xdm_t xdm_tmpfs_t:file execmod;
> +
>   # Run Xorg.wrap
>   can_exec(xserver_t, xserver_exec_t)
>   
> Index: refpolicy-2.20210908/config/appconfig-mcs/seusers
> ===================================================================
> --- refpolicy-2.20210908.orig/config/appconfig-mcs/seusers
> +++ refpolicy-2.20210908/config/appconfig-mcs/seusers
> @@ -1,2 +1,3 @@
>   root:unconfined_u:s0-mcs_systemhigh
>   __default__:unconfined_u:s0-mcs_systemhigh
> +sddm:xdm:s0
> Index: refpolicy-2.20210908/policy/users
> ===================================================================
> --- refpolicy-2.20210908.orig/policy/users
> +++ refpolicy-2.20210908/policy/users
> @@ -27,6 +27,7 @@ gen_user(system_u,, system_r, s0, s0 - m
>   gen_user(user_u, user, user_r, s0, s0)
>   gen_user(staff_u, staff, staff_r sysadm_r ifdef(`enable_mls',`secadm_r auditadm_r'), s0, s0 - mls_systemhigh, mcs_allcats)
>   gen_user(sysadm_u, sysadm, sysadm_r, s0, s0 - mls_systemhigh, mcs_allcats)
> +gen_user(xdm, user, xdm_r, s0, s0)
>   
>   # Until order dependence is fixed for users:
>   ifdef(`direct_sysadm_daemon',`
> Index: refpolicy-2.20210908/config/appconfig-mcs/xdm_default_contexts
> ===================================================================
> --- /dev/null
> +++ refpolicy-2.20210908/config/appconfig-mcs/xdm_default_contexts
> @@ -0,0 +1 @@
> +system_r:xdm_t:s0		xdm_r:xdm_t:s0
> Index: refpolicy-2.20210908/policy/modules/kernel/kernel.te
> ===================================================================
> --- refpolicy-2.20210908.orig/policy/modules/kernel/kernel.te
> +++ refpolicy-2.20210908/policy/modules/kernel/kernel.te
> @@ -32,6 +32,7 @@ role system_r;
>   role sysadm_r;
>   role staff_r;
>   role user_r;
> +role xdm_r;
>   
>   # here until order dependence is fixed:
>   role unconfined_r;

I'm confused by this.  There is a login that happens prior to SDDM starting? 
There also is no role change allowed from xdm_r to the user role.


-- 
Chris PeBenito