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Subject: Re: certbot patch
To:     russell@coker.com.au,
        "selinux-refpolicy@vger.kernel.org" 
        <selinux-refpolicy@vger.kernel.org>
References: <3935693.2ZXyPmJE1a@xev>
From:   Chris PeBenito <pebenito@ieee.org>
Message-ID: <d9b9d1f3-2615-40a9-2eba-98542b0ddfda@ieee.org>
Date:   Sun, 16 Feb 2020 10:32:33 -0500
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On 2/11/20 10:08 PM, Russell Coker wrote:
> This patch against the git refpolicy adds a domain for the certbot client for
> letsencrypt.  This allows automatic renewal of certbot certificates.

Please inline the patch and add signed-off-by.

 > Index: refpolicy-2.20200209/policy/modules/services/certbot.fc
 > ===================================================================
 > --- /dev/null
 > +++ refpolicy-2.20200209/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_var_lib_t,s0)
 > Index: refpolicy-2.20200209/policy/modules/services/certbot.if
 > ===================================================================
 > --- /dev/null
 > +++ refpolicy-2.20200209/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;
 > +')
 > Index: refpolicy-2.20200209/policy/modules/services/certbot.te
 > ===================================================================
 > --- /dev/null
 > +++ refpolicy-2.20200209/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_var_run_t;

Please rename to certbot_runtime_t.


 > +files_pid_file(certbot_var_run_t)
 > +
 > +type certbot_tmp_t;
 > +files_tmp_file(certbot_tmp_t)
 > +
 > +type certbot_tmpfs_t;
 > +files_tmpfs_file(certbot_tmpfs_t)
 > +
 > +type certbot_var_lib_t;
 > +files_type(certbot_var_lib_t)

I'm trying to get away from encoding the path into the type name. Please 
use certbot_lib_t or another name that makes more sense, if possible.


 > +########################################
 > +#
 > +# Local policy
 > +#
 > +
 > +allow certbot_t self:fifo_file { getattr ioctl read write };
 > +
 > +allow certbot_t self:capability { chown dac_override sys_resource };
 > +
 > +# this is for certbot to have write-exec memory, I know it is bad
 > +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_var_run_t:file { map execute };
 > +
 > +kernel_search_fs_sysctls(certbot_t)
 > +
 > +allow certbot_t self:tcp_socket all_tcp_socket_perms;
 > +allow certbot_t self:netlink_route_socket create_netlink_socket_perms;
 > +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)
 > +
 > +allow certbot_t self:udp_socket all_udp_socket_perms;
 > +sysnet_read_config(certbot_t)
 > +files_read_etc_files(certbot_t)
 > +
 > +# for /usr/bin/x86_64-linux-gnu-gcc-8 why?
 > +corecmd_exec_bin(certbot_t)
 > +# for /usr/lib/gcc/x86_64-linux-gnu/8/collect2
 > +libs_exec_lib_files(certbot_t)
 > +
 > +libs_exec_ldconfig(certbot_t)
 > +
 > +apache_search_config(certbot_t)
 > +
 > +# for bin_t map
 > +corecmd_bin_entry_type(certbot_t)

There is a better interface that doesn't allow a bin_t entrypoint, 
corecmd_mmap_bin_files().


 > +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)
 > +
 > +manage_files_pattern(certbot_t, certbot_var_run_t, certbot_var_run_t)
 > +files_pid_filetrans(certbot_t, certbot_var_run_t, file)
 > +
 > +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;
 > +
 > +files_search_var_lib(certbot_t)
 > +manage_dirs_pattern(certbot_t, certbot_var_lib_t, certbot_var_lib_t)
 > +manage_files_pattern(certbot_t, certbot_var_lib_t, certbot_var_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 })
 > +
 > +domain_use_interactive_fds(certbot_t)
 > +userdom_use_user_ptys(certbot_t)
 > +userdom_dontaudit_search_user_home_dirs(certbot_t)
 > +
 > +optional_policy(`
 > +    # for writing to webroot
 > +    apache_manage_sys_content(certbot_t)
 > +')

In general the style (line ordering) needs to be revised.


-- 
Chris PeBenito