CGI Script permissions

[Paul Howarth]

On Thu, 2006-06-08 at 15:03 -0400, Daniel J Walsh wrote:
> Paul Howarth wrote:
> > On Fri, 2006-05-26 at 14:18 -0400, Daniel J Walsh wrote: 
> >   
> >> Paul Howarth wrote:
> >>     
> >>> I made something similar for my moin wiki running under mod_fcgid:
> >>>
> >>> te file:
> >>>
> >>> policy_module(apache, 0.2.1)
> >>>
> >>> require {
> >>>         type devpts_t;
> >>>         type httpd_t;
> >>>         type httpd_log_t;
> >>>         type httpd_sys_script_exec_t;
> >>>         type var_run_t;
> >>> };
> >>>
> >>> # ==========================================================
> >>> # Create and use httpd_fastcgi_script_t for mod_fcgid apps
> >>> # ==========================================================
> >>>
> >>> apache_content_template(fastcgi)
> >>> kernel_read_kernel_sysctls(httpd_fastcgi_script_t)
> >>>
> >>> # Allow FastCGI applications to live alongside regular CGI apps
> >>> allow httpd_fastcgi_script_t httpd_sys_script_exec_t:dir { 
> >>> search_dir_perms };
> >>>
> >>> # Allow FastCGI applications to listen for FastCGI requests on their
> >>> # sockets and respond to them
> >>> allow httpd_fastcgi_script_t httpd_t:unix_stream_socket { 
> >>> rw_stream_socket_perms };
> >>>
> >>> # FastCGI application doing something to the httpd error log
> >>> dontaudit httpd_fastcgi_script_t httpd_log_t:file ioctl;
> >>>
> >>> # Not sure what this is doing (happens when fastcgi scripts start)
> >>> dontaudit httpd_t devpts_t:chr_file ioctl;
> >>>
> >>> # mod_fcgid setting attr of its socket dir
> >>> allow httpd_t var_run_t:dir setattr;
> >>>       
> >> Why not create a context for its socket dir so you don't need this for 
> >> var_run?
> >>     
> >
> > The obvious type to use would really be httpd_var_run_t rather than
> > creating a new type (comparing with other users of /var/run). In fact I
> > think I tried that but it seemed worse than leaving it the default
> > var_run_t and adding the one allow rule. What would you suggest?
> >
> >   
> What errors do you see?
> 
> We already have these rules in policy
> 
> allow httpd_t httpd_var_run_t:file create_file_perms;
> allow httpd_t httpd_var_run_t:sock_file create_file_perms;
> allow httpd_t httpd_var_run_t:dir rw_dir_perms;
> files_pid_filetrans(httpd_t,httpd_var_run_t, { file sock_file })
> 
> Which should be able to handle this if you relabel the /var/run/XYZ dir.

Looks like it's just the same one now:

type=AVC msg=audit(1149799121.917:265395): avc:  denied  { setattr } for
pid=10825 comm="httpd" name="mod_fcgid" dev=dm-4 ino=458818
scontext=user_u:system_r:httpd_t:s0
tcontext=system_u:object_r:httpd_var_run_t:s0 tclass=dirtype=SYSCALL
msg=audit(1149799121.917:265395): arch=40000003 syscall=212 success=yes
exit=0 a0=87639d0 a1=30 a2=ffffffff a3=30 items=1 pid=10825 auid=500
uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 comm="httpd"
exe="/usr/sbin/httpd"
type=CWD msg=audit(1149799121.917:265395):  cwd="/"
type=PATH msg=audit(1149799121.917:265395): item=0
name="/etc/httpd/run/mod_fcgid" flags=1  inode=458818 dev=fd:04
mode=040755 ouid=48 ogid=48 rdev=00:00

(/etc/httpd/run is a symlink to /var/run)

So I guess I just change the rule to be for httpd_var_run_t rather than
var_run_t (rw_dir_perms doesn't include setattr)?

> >>> fc file:
> >>>
> >>> /srv/www/tips/cgi-bin/moin.fcgi -- 
> >>> gen_context(system_u:object_r:httpd_fastcgi_script_exec_t,s0)
> >>> /var/www/tips/cgi-bin/moin.fcgi -- 
> >>> gen_context(system_u:object_r:httpd_fastcgi_script_exec_t,s0)
> >>>
> >>> Paul.
> >>>       
> >> I think it might be a good idea to add this (fastcgi that is) policy to 
> >> base.  Have you tried to submit it upstream?
> >>     
> >
> > Not yet; it probably needs more work to add further capabilities, as
> > I've only use one application with FastCGI myself, and I can see that
> > httpd_sys_script_t has far more capabilities that I've so far allowed to
> > httpd_fastcgi_script_t. Perhaps there should be a interface that goes
> > further than apache_content_template and adds capabilities needed by
> > most server-side scripts (e.g. the kernel_read_kernel_sysctls from
> > above), for use in developing custom types like httpd_fastcgi_script_t?
> >
> > Paul.
> >
> >
> >   
> 
> you could create an
> apache_fastcgi_content_template in an if to do what you want.
> 
> 
> Almost all httpd_sys_ rules are defined in apache_content_template

What I currently have is:

policy_module(fastcgi, 0.1.0)

require {
        type devpts_t;
        type httpd_t;
        type httpd_config_t;
        type httpd_log_t;
        type httpd_sys_script_exec_t;
        type httpd_sys_content_t;
        type var_run_t;
};

# ==========================================================
# Create and use httpd_fastcgi_script_t for mod_fcgid apps
# ==========================================================

apache_content_template(fastcgi)
kernel_read_kernel_sysctls(httpd_fastcgi_script_t)

# Allow FastCGI applications to live alongside regular CGI apps
allow httpd_fastcgi_script_t httpd_sys_script_exec_t:dir
{ search_dir_perms };
allow httpd_fastcgi_script_t httpd_sys_content_t:dir
{ search_dir_perms };

# Allow FastCGI applications to read the routing table
allow httpd_fastcgi_script_t self:netlink_route_socket
{ r_netlink_socket_perms };

# Allow FastCGI applications to listen for FastCGI requests on their
# sockets and respond to them
allow httpd_fastcgi_script_t httpd_t:unix_stream_socket
{ rw_stream_socket_perms };

# FastCGI application doing something to the httpd error log
dontaudit httpd_fastcgi_script_t httpd_log_t:file ioctl;

# Not sure what this is doing (happens when fastcgi scripts start)
dontaudit httpd_t devpts_t:chr_file ioctl;

# mod_fcgid setting attr of its socket dir
allow httpd_t var_run_t:dir setattr;

# ======================================================
# Equivalent policy cribbed from httpd_sys_script_t
# ======================================================

dontaudit httpd_fastcgi_script_t httpd_config_t:dir search;

files_search_var_lib(httpd_fastcgi_script_t)
files_search_spool(httpd_fastcgi_script_t)

ifdef(`distro_redhat',`
        allow httpd_fastcgi_script_t httpd_log_t:file { getattr
append };
')

ifdef(`targeted_policy',`
        tunable_policy(`httpd_enable_homedirs',`

userdom_search_generic_user_home_dirs(httpd_fastcgi_script_t)
        ')
')

optional_policy(`
        mysql_stream_connect(httpd_fastcgi_script_t)
        mysql_rw_db_sockets(httpd_fastcgi_script_t)
')

Paul.