On Tue, Jul 02, 2019 at 03:55:59PM +0300, Alexander Miroshnichenko wrote:
> Add a SELinux Reference Policy module for the
> Knot authoritative-only DNS server.
Some observations in line below
>
> Signed-off-by: Alexander Miroshnichenko <alex@xxxxxxxxxxxxxx>
> ---
> policy/modules/roles/sysadm.te | 4 +
> policy/modules/services/knot.fc | 11 +++
> policy/modules/services/knot.if | 156 ++++++++++++++++++++++++++++++++
> policy/modules/services/knot.te | 92 +++++++++++++++++++
> 4 files changed, 263 insertions(+)
> create mode 100644 policy/modules/services/knot.fc
> create mode 100644 policy/modules/services/knot.if
> create mode 100644 policy/modules/services/knot.te
>
> diff --git a/policy/modules/roles/sysadm.te b/policy/modules/roles/sysadm.te
> index 8f891c83865f..e3079ad65d17 100644
> --- a/policy/modules/roles/sysadm.te
> +++ b/policy/modules/roles/sysadm.te
> @@ -550,6 +550,10 @@ optional_policy(`
> keystone_admin(sysadm_t, sysadm_r)
> ')
>
> +optional_policy(`
> + knotc_role(sysadm_r, sysadm_t)
> +')
> +
> optional_policy(`
> kismet_admin(sysadm_t, sysadm_r)
> ')
> diff --git a/policy/modules/services/knot.fc b/policy/modules/services/knot.fc
> new file mode 100644
> index 000000000000..a809fbc72b14
> --- /dev/null
> +++ b/policy/modules/services/knot.fc
> @@ -0,0 +1,11 @@
> +/etc/knot(/.*)? gen_context(system_u:object_r:knot_conf_t,s0)
> +
> +/usr/sbin/knotd -- gen_context(system_u:object_r:knotd_exec_t,s0)
> +
> +/usr/sbin/knotc -- gen_context(system_u:object_r:knotc_exec_t,s0)
> +
> +/var/lib/knot(/.*)? gen_context(system_u:object_r:knot_var_lib_t,s0)
> +
> +/run/knot -d gen_context(system_u:object_r:knot_runtime_t,s0)
redundant, fc spec below covers this
> +
> +/run/knot(/.*)? gen_context(system_u:object_r:knot_runtime_t,s0)
> diff --git a/policy/modules/services/knot.if b/policy/modules/services/knot.if
> new file mode 100644
> index 000000000000..71eec0c9c1e3
> --- /dev/null
> +++ b/policy/modules/services/knot.if
> @@ -0,0 +1,156 @@
> +
> +## <summary>policy for knotc</summary>
"high-performance authoritative-only DNS server."
> +
> +########################################
> +## <summary>
> +## Execute knotd_exec_t in the knotd domain.
> +## </summary>
> +## <param name="domain">
> +## <summary>
> +## Domain allowed to transition.
> +## </summary>
> +## </param>
> +#
> +interface(`knotd_domtrans',`
> + gen_require(`
> + type knotd_t, knotd_exec_t;
> + ')
> +
> + corecmd_search_bin($1)
> + domtrans_pattern($1, knotd_exec_t, knotd_t)
> +')
> +
> +########################################
> +## <summary>
> +## Manage knot runtime files.
Manage Knot runtime (its not just files)
> +## </summary>
> +## <param name="domain">
> +## <summary>
> +## Domain allowed access.
> +## </summary>
> +## </param>
> +#
> +interface(`knot_manage_runtime_files',`
knot_manage_runtime (its not just files)
> + gen_require(`
> + type knot_runtime_t;
> + type var_run_t;
not allowed to reference external types. also its not used anyway
> + ')
> +
> + manage_dirs_pattern($1, knot_runtime_t, knot_runtime_t)
> + manage_files_pattern($1, knot_runtime_t, knot_runtime_t)
> + manage_lnk_files_pattern($1, knot_runtime_t, knot_runtime_t)
> + manage_sock_files_pattern($1, knot_runtime_t, knot_runtime_t)
Add files_search_pids($1) to allow callers to traverse /run (you cannot "manage knot runtime" if you cannot traverse /run)
> + search_dirs_pattern($1, knot_runtime_t, knot_runtime_t)
redundant as the manage_dirs_pattern($1, knot_runtime_t, knot_runtime_t) above already covers this
> + files_pid_filetrans($1, knot_runtime_t, { file dir sock_file})
This does not belong in this interface. you would create a seperate knot_runtime_filetrans() instead. Also you can remove the "file" and "sock_file" here. Everything is inside /run/knot (as per the fc spec above)
> +')
> +
> +########################################
> +## <summary>
> +## Knot /var/lib files mamange.
cannot parse "mamange" use "Knot manage var lib."
> +## </summary>
> +## <param name="domain">
> +## <summary>
> +## Domain allowed access.
> +## </summary>
> +## </param>
> +#
> +interface(`knot_manage_var_lib_files',`
knot_manage_var_lib (its not just files)
> + gen_require(`
> + type knot_var_lib_t;
> + ')
> +
> + manage_dirs_pattern($1, knot_var_lib_t, knot_var_lib_t)
> + manage_files_pattern($1, knot_var_lib_t, knot_var_lib_t)
> + manage_lnk_files_pattern($1, knot_var_lib_t, knot_var_lib_t)
Add files_search_var_lib($1) because caller cannot "manage Knot var lib" if it cannot traverse /var/lib
> + allow $1 knot_var_lib_t:file map;
this (probably) does not belong here: you would create a knot_mmap_var_lib_files() instead, i suppose)
> + files_var_lib_filetrans($1, knot_var_lib_t, { file dir })
This does not belong here. you would create a knot_var_lib_filetrans() instead.
> +')
> +
> +########################################
> +## <summary>
> +## Knot /etc/knot files read.
knot_read_config_files (as read_files_pattern($1, knot_conf_t, knot_conf_t) only allows for reading files)
> +## </summary>
> +## <param name="domain">
> +## <summary>
> +## Domain allowed access.
> +## </summary>
> +## </param>
> +#
> +interface(`knot_read_conf',`
knot_read_config_files (because this interface allows callers to only "read" knot_conf_t files (not dirs or anything else)
> + gen_require(`
> + type knot_conf_t;
> + type initrc_t;
This does not belong here. not allowed to reference external types directly
> + ')
> +
> + mmap_read_files_pattern($1, knot_conf_t, knot_conf_t)
this does not belong here, if you need map then create a knot_mmap_config_file()
> + read_files_pattern(initrc_t, knot_conf_t, knot_conf_t)
Youre not allowed to reference initrc_t here. Use instead: read_files_pattern($1, knot_conf_t, knot_conf_t)
Add files_search_etc($1) to allow callers to traverse /etc
> +')
> +
> +########################################
> +## <summary>
> +## Manage knot temporary files.
Manage Knot tmp (this interface also allows caller to manage knot_tmp_t dirs, so "files" is not accurate)
> +## </summary>
> +## <param name="domain">
> +## <summary>
> +## Domain allowed access.
> +## </summary>
> +## </param>
> +#
> +interface(`knot_manage_tmpfs_files',`
knot_manage_tmp (this also allows managing dirs)
> + gen_require(`
> + type knot_tmp_t;
> + ')
> +
> + files_tmp_filetrans($1, knot_tmp_t, { file dir })
You would create a knot_tmp_filetrans for the above, and "file" can be removed as everything is in the dir.
> + allow $1 knot_tmp_t:file map;
This probably does not belong here you would create a knot_mmap_tmp_files() instead.
> + allow $1 knot_tmp_t:file manage_file_perms;
> + allow $1 knot_tmp_t:dir manage_dir_perms;
> +')
> +
> +########################################
> +## <summary>
> +## Execute knotc_exec_t in the knotc domain.
"Execute knotc in the knotc domain". Ones does not "execute" types
> +## </summary>
> +## <param name="domain">
> +## <summary>
> +## Domain allowed to transition.
> +## </summary>
> +## </param>
> +#
> +interface(`knotc_domtrans',`
> + gen_require(`
> + type knotc_t, knotc_exec_t;
> + ')
> +
> + corecmd_search_bin($1)
> + domtrans_pattern($1, knotc_exec_t, knotc_t)
> +')
> +
> +########################################
> +## <summary>
> +## Role access for knotc
> +## </summary>
> +## <param name="role">
> +## <summary>
> +## Role allowed access
> +## </summary>
> +## </param>
> +## <param name="domain">
> +## <summary>
> +## User domain for the role
> +## </summary>
> +## </param>
> +#
> +interface(`knotc_role',`
> + gen_require(`
> + type knotc_t;
> + attribute_role knotc_roles;
> + ')
> +
> + roleattribute $1 knotc_roles;
> +
> + knotc_domtrans($2)
> +
> + ps_process_pattern($2, knotc_t)
> + allow $2 knotc_t:process { signull signal sigkill };
> +')
> diff --git a/policy/modules/services/knot.te b/policy/modules/services/knot.te
> new file mode 100644
> index 000000000000..d96b7bf4ce98
> --- /dev/null
> +++ b/policy/modules/services/knot.te
> @@ -0,0 +1,92 @@
> +policy_module(knot, 1.0.0)
> +
> +########################################
> +#
> +# Declarations
> +#
> +
> +type knotd_t;
> +type knotd_exec_t;
> +init_daemon_domain(knotd_t, knotd_exec_t)
> +
> +type knotc_t;
> +type knotc_exec_t;
> +application_domain(knotc_t, knotc_exec_t)
> +init_daemon_domain(knotc_t, knotc_exec_t)
init_system_domain() as knotc is short-running not long-running
> +role knotc_roles types knotc_t;
> +
> +attribute_role knotc_roles;
> +roleattribute system_r knotc_roles;
redundant as init_system_domain() already authorizes system_r to knotc_t
> +
> +type knot_conf_t;
> +files_type(knot_conf_t)
files_config_file(knot_conf_t)
> +
> +type knot_runtime_t;
> +files_pid_file(knot_runtime_t)
> +
> +type knot_var_lib_t;
> +files_type(knot_var_lib_t)
> +
> +type knot_tmp_t;
> +files_tmp_file(knot_tmp_t)
> +
> +########################################
> +#
> +# knotd local policy
> +#
> +allow knotd_t self:capability { dac_read_search setgid setpcap setuid };
You might need dac_override here as indicated by setuid/setgid
> +allow knotd_t self:process { fork signal_perms getcap getsched setsched };
fork is probably redundant since all "domain" is allowed to fork
> +allow knotd_t self:tcp_socket create_stream_socket_perms;
> +allow knotd_t self:udp_socket create_stream_socket_perms;
udp is not connection based, use create_socket_perms for udp
> +allow knotd_t self:unix_stream_socket create_stream_socket_perms;
> +
> +corenet_tcp_bind_generic_node(knotd_t)
> +corenet_udp_bind_generic_node(knotd_t)
> +
> +corenet_sendrecv_dns_server_packets(knotd_t)
> +corenet_tcp_bind_dns_port(knotd_t)
> +corenet_udp_bind_dns_port(knotd_t)
> +# Slave replication
> +corenet_tcp_connect_dns_port(knotd_t)
> +
> +kernel_read_kernel_sysctls(knotd_t)
> +
> +knot_read_conf(knotd_t)
> +knot_manage_runtime_files(knotd_t)
> +knot_manage_tmpfs_files(knotd_t)
> +
> +# Read /etc/passwd
> +files_read_etc_files(knotd_t)
> +# Read /etc/{resolv.conf,hosts}
> +sysnet_read_config(knotd_t)
you probably want sysnet_dns_name_resolve() for slave replication (ie when you use dns names instead of ip addresses to connect to master
> +
> +fs_dontaudit_getattr_xattr_fs(knotd_t)
> +
> +fs_dontaudit_getattr_tmpfs(knotd_t)
I would probably just allow the above two. Use dontaudit rules conservatively
> +
> +logging_send_syslog_msg(knotd_t)
> +
> +miscfiles_read_localization(knotd_t)
> +
> +########################################
> +#
> +# knotc local policy
> +#
> +
> +allow knotc_t self:capability { dac_override dac_read_search };
> +
> +stream_connect_pattern(knotc_t, knot_runtime_t, knot_runtime_t, knotd_t)
> +
> +knot_read_conf(knotc_t)
> +knot_manage_tmpfs_files(knotc_t)
> +knot_manage_var_lib_files(knotc_t)
> +
> +files_dontaudit_search_var_lib(knotc_t)
This can be removed when you fix knot_manage_var_lib() It did not make sense. knotc can never get to /var/lib/knot if its not allowed to traverse /var/lib
> +
> +fs_dontaudit_getattr_tmpfs(knotc_t)
I would just allow this
> +
> +domain_use_interactive_fds(knotc_t)
> +
> +miscfiles_read_localization(knotc_t)
> +
> +userdom_use_user_ptys(knotc_t)
> --
> 2.21.0
>
--
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Dominick Grift
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