nginx policy

[Dominick Grift]

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On 03/14/2011 10:07 AM, Mossburg wrote:
> I'm currently trying to write a policy for the nginx webserver.

It is probably better to make this webserver run in the httpd_t domain.

That means that you would have to add file context specifications for
some files included with the nginx package:

its executable file, configuration file, pid file, log, lib and init
script file.

You did not include your nginx.fc file and so i cannot suggest these
changes.

Ofcourse you can also do it your way and write policy from scratch but
doing this for a web server is probably not the best idea. webservers
can be pretty complex and can be configured in many ways.

So again, i would suggest trying to run nginx in the existing httpd_t
domain instead so that httpd's proven policy applies to nginx, Saves
work/time.

> As i am a beginner i would like to know  if somebody could give me
> some advices to avoid common mistakes.
> To write this policy i've followed this steps :
> - generate a policy with policygentool
> - analyse logs to adapt the policy
> - apply some more changes to fit my needs
> - run the nginx webserver with the new policy loaded.
> 
> For instant, i am running a simple website that serves only static
> content, i have no "avc denied" in logs.
> How could i fully test the policy in order to validate it ? How could
> i improve the policy ?
> 
> Here is my type enforcement file :
> 
> #### nginx.te ####
> policy_module(nginx,1.0.0)
> 
> require {
>         type sysctl_t;
>         type sysctl_kernel_t;
>         type node_t;
> }
> 
> ########################################
> #
> # Declarations
> #
> 
> type nginx_t;
> type nginx_exec_t;
> domain_type(nginx_t)
> init_daemon_domain(nginx_t, nginx_exec_t)
> 
> # configuration files
> # TODO: use files_config_file instead files_type
> type nginx_conf_t;
> files_type(nginx_conf_t)
> 
> # pid files
> type nginx_var_run_t;
> files_pid_file(nginx_var_run_t)
> 
> # log files
> type nginx_var_log_t;
> logging_log_file(nginx_var_log_t)
> 
> # var/lib files
> type nginx_var_lib_t;
> files_type(nginx_var_lib_t)
> 
> ########################################
> #
> # nginx local policy
> #
> # Check in /etc/selinux/refpolicy/include for macros to use instead of
> allow rules
> 
> # Some common macros (you might be able to remove some)
> files_search_etc(nginx_t)
> libs_use_ld_so(nginx_t)
> libs_use_shared_libs(nginx_t)
> miscfiles_read_localization(nginx_t)
> ## internal communication is often done using fifo and unix sockets.
> allow nginx_t self:fifo_file { read write };
> allow nginx_t self:unix_stream_socket create_stream_socket_perms;
> 
> # conf files
> allow nginx_t nginx_conf_t:dir list_dir_perms;
> allow nginx_t nginx_conf_t:file read_file_perms;
> allow nginx_t nginx_conf_t:lnk_file read_lnk_file_perms;
> files_etc_filetrans(nginx_t,nginx_conf_t, { file dir })
> 
> # pid file
> allow nginx_t nginx_var_run_t:file manage_file_perms;
> allow nginx_t nginx_var_run_t:sock_file manage_file_perms;
> allow nginx_t nginx_var_run_t:dir rw_dir_perms;
> files_pid_filetrans(nginx_t,nginx_var_run_t, { file sock_file })
> 
> # log files
> allow nginx_t nginx_var_log_t:file { create_file_perms append };
> allow nginx_t nginx_var_log_t:sock_file create_file_perms;
> allow nginx_t nginx_var_log_t:dir { rw_dir_perms setattr };
> logging_log_filetrans(nginx_t,nginx_var_log_t,{ sock_file file dir })
> 
> # var/lib files for nginx
> allow nginx_t nginx_var_lib_t:file create_file_perms;
> allow nginx_t nginx_var_lib_t:sock_file create_file_perms;
> allow nginx_t nginx_var_lib_t:dir { search_dir_perms create_dir_perms };
> files_var_lib_filetrans(nginx_t,nginx_var_lib_t, { file dir sock_file })
> 
> ## Networking basics (adjust to your needs!)
> sysnet_dns_name_resolve(nginx_t)
> corenet_tcp_sendrecv_all_if(nginx_t)
> corenet_tcp_sendrecv_all_nodes(nginx_t)
> corenet_tcp_sendrecv_all_ports(nginx_t)
> #corenet_non_ipsec_sendrecv(nginx_t)
> corenet_all_recvfrom_unlabeled(nginx_t)
> corenet_tcp_connect_http_port(nginx_t)
> #corenet_tcp_connect_all_ports(nginx_t)
> ## if it is a network daemon, consider these:
> #corenet_tcp_bind_all_ports(nginx_t)
> #corenet_tcp_bind_all_nodes(nginx_t)
> corenet_tcp_bind_http_port(nginx_t)
> corenet_tcp_bind_http_cache_port(nginx_t)
> allow nginx_t self:tcp_socket { listen accept };
> allow nginx_t node_t:tcp_socket node_bind;
> 
> # Init script handling
> init_use_fds(nginx_t)
> init_use_script_ptys(nginx_t)
> domain_use_interactive_fds(nginx_t)
> 
> # System
> allow nginx_t self:capability { setuid net_bind_service setgid dac_override };
> 
> kernel_read_kernel_sysctls(nginx_t)
> #allow nginx_t sysctl_kernel_t:dir search;
> #allow nginx_t sysctl_kernel_t:file read;
> #allow nginx_t sysctl_t:dir search;
> allow nginx_t etc_t:dir search;
> 
> # Access apache content
> apache_manage_sys_content(nginx_t)
> apache_search_sys_content(nginx_t)
> apache_read_sys_content(nginx_t)
> 
> files_search_mnt(nginx_t)
> files_read_etc_files(nginx_t)
> files_read_usr_files(nginx_t)
> miscfiles_read_certs(nginx_t)
> 
> --
> Jérémy
> --
> selinux mailing list
> selinux at lists.fedoraproject.org
> https://admin.fedoraproject.org/mailman/listinfo/selinux

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