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From:   Dominick Grift <dominick.grift@defensec.nl>
To:     Russell Coker <russell@coker.com.au>
Cc:     selinux-refpolicy@vger.kernel.org
Subject: Re: [PATCH] misc network patches
References: <YAf6/c8XKLACDF9P@xev>
Date:   Wed, 20 Jan 2021 14:23:29 +0100
In-Reply-To: <YAf6/c8XKLACDF9P@xev> (Russell Coker's message of "Wed, 20 Jan
        2021 20:42:21 +1100")
Message-ID: <ypjla6t3n3n2.fsf@defensec.nl>
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Russell Coker <russell@coker.com.au> writes:

> Collection of net related patches, ready for inclusion.
>
> Signed-off-by: Russell Coker <russell@coker.com.au>
>
> Index: refpolicy-2.20210120/policy/modules/admin/netutils.te
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/admin/netutils.te
> +++ refpolicy-2.20210120/policy/modules/admin/netutils.te
> @@ -109,6 +109,7 @@ allow ping_t self:tcp_socket create_sock
>  allow ping_t self:rawip_socket { create ioctl read write bind getopt setopt getattr };
>  allow ping_t self:packet_socket { create ioctl read write bind getopt setopt };
>  allow ping_t self:netlink_route_socket create_netlink_socket_perms;
> +allow ping_t self:icmp_socket create;
>  
>  corenet_all_recvfrom_netlabel(ping_t)
>  corenet_sendrecv_icmp_packets(ping_t)
> @@ -164,13 +165,14 @@ allow traceroute_t self:capability { net
>  allow traceroute_t self:fifo_file rw_inherited_fifo_file_perms;
>  allow traceroute_t self:process signal;
>  allow traceroute_t self:rawip_socket create_socket_perms;
> -allow traceroute_t self:packet_socket create_socket_perms;
> +allow traceroute_t self:packet_socket { map create_socket_perms };
>  allow traceroute_t self:udp_socket create_socket_perms;
>  
>  can_exec(traceroute_t, traceroute_exec_t)
>  
>  kernel_read_system_state(traceroute_t)
>  kernel_read_network_state(traceroute_t)
> +kernel_search_fs_sysctls(traceroute_t)
>  
>  corecmd_search_bin(traceroute_t)
>  
> @@ -205,6 +207,7 @@ auth_use_nsswitch(traceroute_t)
>  
>  logging_send_syslog_msg(traceroute_t)
>  
> +miscfiles_read_generic_certs(traceroute_t)
>  miscfiles_read_localization(traceroute_t)
>  
>  userdom_use_inherited_user_terminals(traceroute_t)
> Index: refpolicy-2.20210120/policy/modules/system/sysnetwork.fc
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/system/sysnetwork.fc
> +++ refpolicy-2.20210120/policy/modules/system/sysnetwork.fc
> @@ -27,6 +27,7 @@ ifdef(`distro_debian',`
>  /etc/dhcp3?/dhclient.*		gen_context(system_u:object_r:dhcp_etc_t,s0)
>  
>  /etc/systemd/network(/.*)?	gen_context(system_u:object_r:net_conf_t,s0)
> +/etc/tor/torsocks.conf	--	gen_context(system_u:object_r:net_conf_t,s0)
>  
>  ifdef(`distro_redhat',`
>  /etc/sysconfig/network-scripts/.*resolv\.conf -- gen_context(system_u:object_r:net_conf_t,s0)
> Index: refpolicy-2.20210120/policy/modules/system/sysnetwork.te
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/system/sysnetwork.te
> +++ refpolicy-2.20210120/policy/modules/system/sysnetwork.te
> @@ -5,6 +5,14 @@ policy_module(sysnetwork, 1.26.3)
>  # Declarations
>  #
>  
> +## <desc>
> +##      <p>
> +##      Determine whether DHCP client
> +##      can manage samba
> +##      </p>
> +## </desc>
> +gen_tunable(dhcpc_manage_samba, false)
> +
>  attribute_role dhcpc_roles;
>  roleattribute system_r dhcpc_roles;
>  
> @@ -175,6 +183,15 @@ ifdef(`init_systemd',`
>  ')
>  
>  optional_policy(`
> +	tunable_policy(`dhcpc_manage_samba',`
> +        	samba_manage_var_files(dhcpc_t)
> +		init_exec_script_files(dhcpc_t)
> +		init_get_system_status(dhcpc_t)
> +		samba_restart(dhcpc_t)
> +	')
> +')
> +
> +optional_policy(`
>  	avahi_domtrans(dhcpc_t)
>  ')
>  
> Index: refpolicy-2.20210120/policy/modules/roles/staff.te
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/roles/staff.te
> +++ refpolicy-2.20210120/policy/modules/roles/staff.te
> @@ -15,6 +15,10 @@ userdom_unpriv_user_template(staff)
>  #
>  corenet_ib_access_unlabeled_pkeys(staff_t)
>  
> +corenet_tcp_bind_all_unreserved_ports(staff_t)
> +corenet_udp_bind_all_unreserved_ports(staff_t)
> +corenet_tcp_bind_generic_node(staff_t)

staff_t is a "unpriv user" and so "userdom_unpriv_user_template()"
applies to staff_t.

this template has two booleans: user_tcp_server and user_udp_server
these booleans currently allow unpriv users to bind tcp and udp sockets
to generic ports respectively.

This is old, inaccurate and outdated. Instead those booleans should
probably be modernized:

	tunable_policy(`user_tcp_server',`
		corenet_tcp_bind_generic_node($1_t)
		corenet_tcp_bind_all_unreserved_ports($1_t)
	')

	tunable_policy(`user_udp_server',`
		corenet_udp_bind_generic_node($1_t)
		corenet_udp_bind_all_unreserved_ports($1_t)
	')

> +
>  optional_policy(`
>  	apache_role(staff_r, staff_t)
>  ')
> @@ -36,6 +40,10 @@ optional_policy(`
>  ')
>  
>  optional_policy(`
> +	netutils_domtrans_ping(staff_t)
> +')
> +

This is already (conditionlly) allowed in the userdom_unpriv_user_template()
To make it work requires a boolean to be set to true (i believe)

> +optional_policy(`
>  	postgresql_role(staff_r, staff_t)
>  ')
>  
> @@ -65,6 +73,11 @@ optional_policy(`
>  ')
>  
>  optional_policy(`
> +	# for torbrowser-launcher
> +	xdg_exec_data(staff_t)

What location is this exactly? ~/.local/bin?

I would associate a "bin_home_t" with ~/.local/bin and only allow that
to be executed, rather than all of ~/.local

But regardless this, or similar rule should apply to
userdom_unpriv_user_template() instead. Use the templates.

> +')
> +
> +optional_policy(`
>  	xscreensaver_role(staff_r, staff_t)
>  ')
>  
> Index: refpolicy-2.20210120/policy/modules/roles/unprivuser.te
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/roles/unprivuser.te
> +++ refpolicy-2.20210120/policy/modules/roles/unprivuser.te
> @@ -7,11 +7,23 @@ policy_module(unprivuser, 2.10.0)
>  #
>  # Declarations
>  #
> +## <desc>
> +## <p>
> +## Allow user to bind all unreserved ports
> +## </p>
> +## </desc>
> +gen_tunable(user_bind_unreserved, false)

Modernize and use the existing user_tcp_server and user_udp_server
booleans in userdom_unpriv_user_template() instead? See above comment.

>  
>  #role user_r;
>  
>  userdom_unpriv_user_template(user)
>  
> +tunable_policy(`user_bind_unreserved', `
> +	corenet_tcp_bind_all_unreserved_ports(user_t)
> +	corenet_udp_bind_all_unreserved_ports(user_t)
> +	corenet_tcp_bind_generic_node(user_t)
> +')

See above comment about user_tcp_server and user_udp_server booleans in userdom_unpriv_user_template()

> +
>  optional_policy(`
>  	apache_role(user_r, user_t)
>  ')
> @@ -25,6 +37,10 @@ optional_policy(`
>  ')
>  
>  optional_policy(`
> +	netutils_domtrans_ping(user_t)
> +')
> +

This is already allowed conditionally in userdom_unpriv_user_template()
requires a boolean to be set to true to work. Adding this rule would
break that existing model.

> +optional_policy(`
>  	screen_role_template(user, user_r, user_t)
>  ')
>  
> @@ -33,6 +49,11 @@ optional_policy(`
>  ')
>  
>  optional_policy(`
> +	# for torbrowser-launcher
> +	xdg_exec_data(user_t)
> +')
> +

What location is this exactly? ~/.local/bin?

I would associate a "bin_home_t" with ~/.local/bin and only allow that
to be executed, rather than all of ~/.local

But regardless this, or similar rule should apply to
userdom_unpriv_user_template() instead. Use the templates.

> +optional_policy(`
>  	xscreensaver_role(user_r, user_t)
>  ')
>  
> Index: refpolicy-2.20210120/policy/modules/services/samba.if
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/services/samba.if
> +++ refpolicy-2.20210120/policy/modules/services/samba.if
> @@ -729,3 +729,22 @@ interface(`samba_admin',`
>  	files_list_tmp($1)
>  	admin_pattern($1, { swat_tmp_t smbd_tmp_t winbind_tmp_t })
>  ')
> +
> +########################################
> +## <summary>
> +##	Restart and get status of samba daemon
> +## </summary>
> +## <param name="domain">
> +##	<summary>
> +##	Domain allowed access.
> +##	</summary>
> +## </param>
> +#
> +interface(`samba_restart',`
> +	gen_require(`
> +		type samba_unit_t;
> +	')
> +
> +	allow $1 samba_unit_t:file getattr;
> +	allow $1 samba_unit_t:service { start stop status reload };

This interface seems a bit broad

> +')
> Index: refpolicy-2.20210120/policy/modules/system/xdg.if
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/system/xdg.if
> +++ refpolicy-2.20210120/policy/modules/system/xdg.if
> @@ -921,6 +921,24 @@ interface(`xdg_watch_documents_dirs',`
>  
>  ########################################
>  ## <summary>
> +##	Allow executing the xdg data home files
> +## </summary>
> +## <param name="domain">
> +##	<summary>
> +##	Domain allowed access.
> +##	</summary>
> +## </param>
> +#
> +interface(`xdg_exec_data',`
> +	gen_require(`
> +		type xdg_data_t;
> +	')
> +
> +	can_exec($1, xdg_data_t)
> +')

It's not very common. Did you add this for ~/.local/bin?

I would probably associate a private "bin_home_t" type with ~/.local/bin

> +
> +########################################
> +## <summary>
>  ##	Create objects in the user home dir with an automatic type transition to
>  ##	the xdg_documents_t type.
>  ## </summary>
> Index: refpolicy-2.20210120/policy/modules/services/mon.te
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/services/mon.te
> +++ refpolicy-2.20210120/policy/modules/services/mon.te
> @@ -58,6 +58,9 @@ manage_files_pattern(mon_t, mon_var_log_
>  manage_files_pattern(mon_t, mon_runtime_t, mon_runtime_t)
>  files_runtime_filetrans(mon_t, mon_runtime_t, file)
>  
> +# to read fips_enabled
> +kernel_read_crypto_sysctls(mon_t)
> +
>  kernel_read_kernel_sysctls(mon_t)
>  kernel_read_network_state(mon_t)
>  kernel_read_system_state(mon_t)
> Index: refpolicy-2.20210120/policy/modules/services/mailman.te
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/services/mailman.te
> +++ refpolicy-2.20210120/policy/modules/services/mailman.te
> @@ -112,6 +112,7 @@ corecmd_exec_bin(mailman_cgi_t)
>  dev_read_urand(mailman_cgi_t)
>  
>  files_search_locks(mailman_cgi_t)
> +files_read_usr_files(mailman_cgi_t)
>  
>  term_use_controlling_term(mailman_cgi_t)
>  
> Index: refpolicy-2.20210120/policy/modules/services/dkim.te
> ===================================================================
> --- refpolicy-2.20210120.orig/policy/modules/services/dkim.te
> +++ refpolicy-2.20210120/policy/modules/services/dkim.te
> @@ -35,6 +35,7 @@ kernel_read_vm_overcommit_sysctl(dkim_mi
>  
>  corenet_udp_bind_generic_node(dkim_milter_t)
>  corenet_udp_bind_all_unreserved_ports(dkim_milter_t)
> +corenet_udp_bind_generic_port(dkim_milter_t)
>  
>  dev_read_urand(dkim_milter_t)
>  # for cpu/online
>

-- 
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Dominick Grift