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From: bauen1 <j2468h@googlemail.com>
To: Chris PeBenito <pebenito@ieee.org>,
	Dominick Grift <dominick.grift@defensec.nl>,
	Russell Coker <russell@coker.com.au>
Cc: selinux-refpolicy@vger.kernel.org
Subject: Re: another certbot patch
Date: Thu, 21 May 2020 16:50:04 +0200
Message-ID: <6351f07d-5c19-7ae7-77af-a8d24779340a@gmail.com> (raw)
In-Reply-To: <c36a04c9-2f9c-a327-4d9d-afdd471c31af@ieee.org>

Hi,

I've now used this for some time and have a couple of things to add.

On 4/14/20 4:54 PM, Chris PeBenito wrote:
> On 4/10/20 4:07 AM, Dominick Grift wrote:
>> 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.
>
>
> I don't have any comments beyond Dominick's.
>
>>> 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)
On my debian system certbot puts private certificates into
/etc/letsencrypt hence I labeled it certbot_lib_t too but that probably
isn't right.
>>> 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)
>>
Swapping the argument order here would be better in line with the rest
of refpolicy.

Calling this for sysadm would also be a good idea since it is usually
used for obtaining the first certificate.

>>> +')
>>> 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;
>>> +

I've found that this is missing a filetrans since certbot might try to
create its own log directory.

Removing 'remove_name reparent rmdir' from the permissions granted on
certbot_log_t is also possible since imho domains normally shouldn't
delete their own but it might be better to keep ':dir manage_dir_perms'

+manage_files_pattern(certbot_t, certbot_log_t, certbot_log_t)
+allow certbot_t certbot_log_t:dir { create_dir_perms search_dir_perms
add_entry_dir_perms };
+logging_log_filetrans(certbot_t, certbot_log_t, dir)


>>> +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">
>>
>
>
Thanks, bauen1


      reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-10  6:02 Russell Coker
2020-04-10  8:07 ` Dominick Grift
2020-04-14 14:54   ` Chris PeBenito
2020-05-21 14:50     ` bauen1 [this message]

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