Hi, running latest RHEL 7.3 ... struggling with an SELinux issue related
to Apache httpd that I just can't figure out. I have always been able
to tune policy or alter a boolean, this one has me stumped!
What I am trying to do: I am trying to deploy a simple, 3 line CGI
script in /var/www/cgi-bin/. Runs fine with enforcement disabled (see
output below). My custom policy for Apache (see below) comes from my
EL6 environment.
The normal setroubleshooting tools don't help, as there is only a single
line in audit.log (of type=SELINUX_ERR)
This is not happening on latest RHEL 6.9 ...
Might be related to systemd? I don't see any "NoNewPrivileges"
directives inside /etc/systemd/ though ... weird!
Many thanks for your help!
-chris
########################################################################
# With enforcement disabled ... all is good (as expected)
########################################################################
# ls -laZ /var/www/cgi-bin/
drwxr-xr-x. root root system_u:object_r:httpd_sys_script_exec_t:s0 .
drwxr-xr-x. root root system_u:object_r:httpd_sys_content_t:s0 ..
-rwxr-xr-x. root root system_u:object_r:httpd_sys_script_exec_t:s0 ok.cgi
# setenforce 0
# systemctl restart httpd.service
$ curl localhost/cgi-bin/ok.cgi
OK
########################################################################
# With enforcement enabled ... CGI script fails, all you find is a
# single deny in /var/log/audit/audit.log
########################################################################
# setenforce 1
# systemctl restart httpd.service
# getenforce
Enforcing
$ curl localhost/cgi-bin/ok.cgi
<html><head><title>500 Server Error</title></head><body><h1>Server
Error</h1></body></html>
# tail /var/log/audit/audit.log | grep denied
type=SELINUX_ERR msg=audit(1495468154.591:121695):
op=security_bounded_transition seresult=denied
oldcontext=system_u:system_r:httpd_t:s0
newcontext=system_u:system_r:httpd_sys_script_t:s0
########################################################################
# System details ...
########################################################################
# uname -r
3.10.0-514.16.1.el7.x86_64
# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 7.3 (Maipo)
# sestatus
SELinux status: enabled
SELinuxfs mount: /sys/fs/selinux
SELinux root directory: /etc/selinux
Loaded policy name: targeted
Current mode: enforcing
Mode from config file: enforcing
Policy MLS status: enabled
Policy deny_unknown status: allowed
Max kernel policy version: 28
# find /etc/ -type f | xargs grep NoNewPrivileges
[NO OUTPUT]
# getsebool -a | grep httpd_
httpd_anon_write --> on
httpd_builtin_scripting --> on
httpd_can_check_spam --> off
httpd_can_connect_ftp --> off
httpd_can_connect_ldap --> off
httpd_can_connect_mythtv --> off
httpd_can_connect_zabbix --> off
httpd_can_network_connect --> on
httpd_can_network_connect_cobbler --> off
httpd_can_network_connect_db --> on
httpd_can_network_memcache --> off
httpd_can_network_relay --> off
httpd_can_sendmail --> on
httpd_dbus_avahi --> on
httpd_dbus_sssd --> off
httpd_dontaudit_search_dirs --> off
httpd_enable_cgi --> on
httpd_enable_ftp_server --> off
httpd_enable_homedirs --> off
httpd_execmem --> off
httpd_graceful_shutdown --> on
httpd_manage_ipa --> off
httpd_mod_auth_ntlm_winbind --> off
httpd_mod_auth_pam --> off
httpd_read_user_content --> on
httpd_run_ipa --> off
httpd_run_preupgrade --> off
httpd_run_stickshift --> off
httpd_serve_cobbler_files --> off
httpd_setrlimit --> off
httpd_ssi_exec --> off
httpd_sys_script_anon_write --> off
httpd_tmp_exec --> off
httpd_tty_comm --> on
httpd_unified --> on
httpd_use_cifs --> off
httpd_use_fusefs --> off
httpd_use_gpg --> off
httpd_use_nfs --> off
httpd_use_openstack --> off
httpd_use_sasl --> off
httpd_verify_dns --> off
# THIS IS MY GENERIC APACHE TE FILE FROM EL6 ...
# cat myapache.te
module myapache 0.4;
require {
type httpd_t;
type httpd_sys_script_t;
type http_port_t;
type mysqld_port_t;
type rpm_var_cache_t;
type kernel_t;
class process { setpgid transition };
class system module_request;
class tcp_socket name_connect;
class dir { read search open getattr };
class file { open read getattr };
}
allow httpd_t rpm_var_cache_t:dir { read search open getattr };
allow httpd_t rpm_var_cache_t:file { read getattr open } ;
allow httpd_t mysqld_port_t:tcp_socket name_connect;
allow httpd_sys_script_t self:process setpgid;
allow httpd_sys_script_t http_port_t:tcp_socket name_connect;
allow httpd_sys_script_t kernel_t:system module_request;
#type=SELINUX_ERR msg=audit(1495467001.822:84934):
op=security_bounded_transition seresult=denied
oldcontext=system_u:system_r:httpd_t:s0
newcontext=system_u:system_r:httpd_sys_script_t:s0
# THIS STILL DOES NOT WORK! SYSTEMD ISSUE?
allow httpd_t httpd_sys_script_t:process transition;
