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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: another certbot patch
References: <20200410060231.GA35896@xev>
Date:   Fri, 10 Apr 2020 10:07:01 +0200
In-Reply-To: <20200410060231.GA35896@xev> (Russell Coker's message of "Fri, 10
        Apr 2020 16:02:31 +1000")
Message-ID: <ypjl7dynn4re.fsf@defensec.nl>
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Russell Coker <russell@coker.com.au> writes:

> Signed-off-by: Russell Coker <russell@coker.com.au>
>
> I think this addresses all the issues Chris raised.
>
>
> Index: refpolicy-2.20200410/policy/modules/services/certbot.fc
> ===================================================================
> --- /dev/null
> +++ refpolicy-2.20200410/policy/modules/services/certbot.fc
> @@ -0,0 +1,4 @@
> +/usr/bin/certbot	--	gen_context(system_u:object_r:certbot_exec_t,s0)
> +/usr/bin/letsencrypt	--	gen_context(system_u:object_r:certbot_exec_t,s0)
> +/var/log/letsencrypt(/.*)?	gen_context(system_u:object_r:certbot_log_t,s0)
> +/var/lib/letsencrypt(/.*)?	gen_context(system_u:object_r:certbot_lib_t,s0)
> Index: refpolicy-2.20200410/policy/modules/services/certbot.if
> ===================================================================
> --- /dev/null
> +++ refpolicy-2.20200410/policy/modules/services/certbot.if
> @@ -0,0 +1,46 @@
> +## <summary>SSL certificate requesting tool certbot AKA letsencrypt.</summary>
> +
> +########################################
> +## <summary>
> +##      Execute certbot/letsencrypt in the certbot
> +##      domain.
> +## </summary>
> +## <param name="domain">
> +##      <summary>
> +##      Domain allowed to transition.
> +##      </summary>
> +## </param>
> +#
> +interface(`certbot_domtrans',`
> +	gen_require(`
> +		type certbot_t, certbot_exec_t;
> +	')
> +
> +	domtrans_pattern($1, certbot_exec_t, certbot_t)
> +')
> +
> +########################################
> +## <summary>
> +##      Execute certbot/letsencrypt in the certbot
> +##      domain, and allow the specified role
> +##      the firstboot domain.
> +## </summary>
> +## <param name="role">
> +##      <summary>
> +##      Role allowed access.
> +##      </summary>
> +## </param>
> +## <param name="domain">
> +##      <summary>
> +##      Domain allowed to transition.
> +##      </summary>
> +## </param>
> +#
> +interface(`certbot_run',`
> +	gen_require(`
> +		type certbot_t;
> +	')
> +
> +	certbot_domtrans($2)
> +	role $1 types certbot_t;

might want to call this: certbot_run(sysadm_r, sysadm_t)

> +')
> Index: refpolicy-2.20200410/policy/modules/services/certbot.te
> ===================================================================
> --- /dev/null
> +++ refpolicy-2.20200410/policy/modules/services/certbot.te
> @@ -0,0 +1,99 @@
> +policy_module(certbot, 1.0.0)
> +
> +########################################
> +#
> +# Declarations
> +#
> +
> +type certbot_t;
> +type certbot_exec_t;
> +init_daemon_domain(certbot_t, certbot_exec_t)
> +
> +type certbot_log_t;
> +logging_log_file(certbot_log_t)
> +
> +type certbot_runtime_t alias certbot_var_run_t;
> +files_pid_file(certbot_runtime_t)
> +
> +type certbot_tmp_t;
> +files_tmp_file(certbot_tmp_t)
> +
> +type certbot_tmpfs_t;
> +files_tmpfs_file(certbot_tmpfs_t)
> +
> +type certbot_lib_t alias certbot_var_lib_t;
> +files_type(certbot_lib_t)

I would have used certbot_state_t here so that "lib" can be used for
private library types

> +
> +########################################
> +#
> +# Local policy
> +#
> +
> +allow certbot_t self:fifo_file { getattr ioctl read write };
> +allow certbot_t self:capability { chown dac_override sys_resource };
> +allow certbot_t self:udp_socket all_udp_socket_perms;
> +allow certbot_t self:tcp_socket all_tcp_socket_perms;
> +allow certbot_t self:netlink_route_socket create_netlink_socket_perms;
> +
> +files_search_var_lib(certbot_t)
> +manage_dirs_pattern(certbot_t, certbot_lib_t, certbot_lib_t)
> +manage_files_pattern(certbot_t, certbot_lib_t, certbot_lib_t)
> +
> +manage_files_pattern(certbot_t, certbot_tmp_t, certbot_tmp_t)
> +files_tmp_filetrans(certbot_t, certbot_tmp_t, { file })
> +
> +manage_files_pattern(certbot_t, certbot_tmpfs_t, certbot_tmpfs_t)
> +fs_tmpfs_filetrans(certbot_t, certbot_tmpfs_t, { file })
> +
> +# this is for certbot to have write-exec memory, I know it is bad
> +# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=913544
> +# the Debian bug report has background about python-acme and python3-openssl
> +allow certbot_t self:process execmem;
> +allow certbot_t certbot_tmp_t:file { map execute };
> +allow certbot_t certbot_tmpfs_t:file { map execute };
> +allow certbot_t certbot_runtime_t:file { map execute };
> +
> +logging_search_logs(certbot_t)
> +allow certbot_t certbot_log_t:dir manage_dir_perms;
> +allow certbot_t certbot_log_t:file manage_file_perms;
> +
> +manage_files_pattern(certbot_t, certbot_runtime_t, certbot_runtime_t)
> +files_pid_filetrans(certbot_t, certbot_runtime_t, file)
> +
> +kernel_search_fs_sysctls(certbot_t)
> +
> +corecmd_exec_bin(certbot_t)
> +corecmd_list_bin(certbot_t)
> +corecmd_mmap_bin_files(certbot_t)

redundant: exec implies mmap

> +
> +corenet_tcp_bind_generic_node(certbot_t)
> +corenet_tcp_connect_http_port(certbot_t)
> +
> +# bind to http port for standalone mode
> +corenet_tcp_bind_http_port(certbot_t)
> +
> +domain_use_interactive_fds(certbot_t)
> +files_read_etc_files(certbot_t)
> +
> +libs_exec_ldconfig(certbot_t)
> +# for /usr/lib/gcc/x86_64-linux-gnu/8/collect2
> +libs_exec_lib_files(certbot_t)
> +
> +miscfiles_read_localization(certbot_t)
> +
> +miscfiles_read_generic_certs(certbot_t)
> +miscfiles_manage_generic_tls_privkey_dirs(certbot_t)
> +miscfiles_manage_generic_tls_privkey_files(certbot_t)
> +miscfiles_manage_generic_tls_privkey_lnk_files(certbot_t)
> +
> +sysnet_read_config(certbot_t)
> +
> +userdom_dontaudit_search_user_home_dirs(certbot_t)
> +userdom_use_user_ptys(certbot_t)
> +
> +optional_policy(`
> +	# for writing to webroot
> +	apache_manage_sys_content(certbot_t)
> +
> +	apache_search_config(certbot_t)
> +')
> Index: refpolicy-2.20200410/policy/modules/system/miscfiles.if
> ===================================================================
> --- refpolicy-2.20200410.orig/policy/modules/system/miscfiles.if
> +++ refpolicy-2.20200410/policy/modules/system/miscfiles.if
> @@ -254,6 +254,26 @@ interface(`miscfiles_manage_generic_tls_
>  
>  ########################################
>  ## <summary>
> +##	Manage generic SSL/TLS private
> +##	keys.
> +## </summary>
> +## <param name="domain">
> +##	<summary>
> +##	Domain allowed access.
> +##	</summary>
> +## </param>
> +## <rolecap/>
> +#
> +interface(`miscfiles_manage_generic_tls_privkey_lnk_files',`
> +	gen_require(`
> +		type tls_privkey_t;
> +	')
> +
> +	manage_lnk_files_pattern($1, tls_privkey_t, tls_privkey_t)
> +')
> +
> +########################################
> +## <summary>
>  ##	Read fonts.
>  ## </summary>
>  ## <param name="domain">

-- 
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Dominick Grift