Mirek,
could you test it with the following local policy


policy_module(mysquid, 1.0)

require{
 type squid_t;
}

userdom_manage_user_tmp_dirs(squid_t)
userdom_manage_user_tmp_files(squid_t)
userdom_tmp_filetrans_user_tmp(squid_t, { file dir })

Thanks Mirek, with this module there are no more denials :)

# getenforce 
Enforcing
# semodule -l | grep squid
mysquid 1.0
squid   1.9.0   
# ausearch -ts recent -m avc
<no matches>

Why is squid touching user_tmp_t?  Squid should get its own tmp files, and probably not be writing in /tmp in the first place?


Is squid reading the krbcc name of users on the same system or is it requiring users to provide credentials before using squid.

From what I gather on the web, squid_kerb_auth accepts Negotiate authentication from clients attempting to use the proxy, so it would use a replay cache.

Miroslav V, can you change your mysquid policy to:

policy_module(mysquid, 1.0)

require{
 type squid_t;
}

kerberos_manage_host_rcache(squid_t)

And try that.  Not sure if kernberos maange_host_rchage will be enough.

I think you might end up needing

allow squid_t tmp_t:dir rw_dir_perms;

Which should probably be in the kerberos_manage_host_rcache interface.

I added fixes for this to F15 policy.

Dan, using this module

policy_module(mysquid, 1.2)

require{
 type squid_t;
 type tmp_t;
}

kerberos_manage_host_rcache(squid_t)
allow squid_t tmp_t:dir rw_dir_perms;

I still see AVC like this:

----
time->Wed Apr 13 17:12:46 2011
type=SYSCALL msg=audit(1302707566.512:1696): arch=40000003 syscall=10 success=no exit=-13 a0=1d9df98 a1=0 a2=1e416c a3=1da4084 items=0 ppid=11348 pid=11350 auid=0 uid=23 gid=23 euid=23 suid=23 fsuid=23 egid=23 sgid=23 fsgid=23 tty=(none) ses=219 comm="squid_kerb_auth" exe="/usr/lib/squid/squid_kerb_auth" subj=unconfined_u:system_r:squid_t:s0 key=(null)
type=AVC msg=audit(1302707566.512:1696): avc:  denied  { unlink } for  pid=11350 comm="squid_kerb_auth" name="HTTP_23" dev=dm-0 ino=393454 scontext=unconfined_u:system_r:squid_t:s0 tcontext=unconfined_u:object_r:user_tmp_t:s0 tclass=file

Please remove HTTP_23 and then try.  The problem is you probably ran squid by hand creating the bogusly labelled HTTP_23 file.

Dan I removed the HTTP_23 and have the module from comment 8 loaded, but it sill cannot create the file. I had to enable don't audit rules to see them:

time->Thu Apr 14 10:20:08 2011
type=SYSCALL msg=audit(1302769208.789:130): arch=40000003 syscall=5 success=no exit=-13 a0=11559b0 a1=2c1 a2=180 a3=2c1 items=0 ppid=11053 pid=11055 auid=0 uid=23 gid=23 euid=23 suid=23 fsuid=23 egid=23 sgid=23 fsgid=23 tty=(none) ses=1 comm="squid_kerb_auth" exe="/usr/lib/squid/squid_kerb_auth" subj=unconfined_u:system_r:squid_t:s0 key=(null)
type=AVC msg=audit(1302769208.789:130): avc:  denied  { create } for  pid=11055 comm="squid_kerb_auth" name="HTTP_23" scontext=unconfined_u:system_r:squid_t:s0 tcontext=unconfined_u:object_r:tmp_t:s0 tclass=file

After putting SELinux into permissive mode I see these AVCs:
time->Thu Apr 14 10:32:23 2011
type=SYSCALL msg=audit(1302769943.042:142): arch=40000003 syscall=5 success=yes exit=3 a0=85e255 a1=8000 a2=1b6 a3=85d4d8 items=0 ppid=11603 pid=11604 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=1 comm="kadmind" exe="/usr/sbin/kadmind" subj=unconfined_u:system_r:kadmind_t:s0 key=(null)
type=AVC msg=audit(1302769943.042:142): avc:  denied  { open } for  pid=11604 comm="kadmind" name="config" dev=dm-0 ino=914485 scontext=unconfined_u:system_r:kadmind_t:s0 tcontext=system_u:object_r:selinux_config_t:s0 tclass=file
type=AVC msg=audit(1302769943.042:142): avc:  denied  { read } for  pid=11604 comm="kadmind" name="config" dev=dm-0 ino=914485 scontext=unconfined_u:system_r:kadmind_t:s0 tcontext=system_u:object_r:selinux_config_t:s0 tclass=file
----
time->Thu Apr 14 10:32:23 2011
type=SYSCALL msg=audit(1302769943.042:143): arch=40000003 syscall=197 success=yes exit=0 a0=3 a1=bfaebc0c a2=ee6ff4 a3=2870438 items=0 ppid=11603 pid=11604 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=1 comm="kadmind" exe="/usr/sbin/kadmind" subj=unconfined_u:system_r:kadmind_t:s0 key=(null)
type=AVC msg=audit(1302769943.042:143): avc:  denied  { getattr } for  pid=11604 comm="kadmind" path="/etc/selinux/config" dev=dm-0 ino=914485 scontext=unconfined_u:system_r:kadmind_t:s0 tcontext=system_u:object_r:selinux_config_t:s0 tclass=file
----
time->Thu Apr 14 10:32:23 2011
type=SYSCALL msg=audit(1302769943.612:144): arch=40000003 syscall=102 success=no exit=-22 a0=2 a1=bfaec150 a2=4152cc a3=0 items=0 ppid=11603 pid=11604 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=1 comm="kadmind" exe="/usr/sbin/kadmind" subj=unconfined_u:system_r:kadmind_t:s0 key=(null)
type=AVC msg=audit(1302769943.612:144): avc:  denied  { name_bind } for  pid=11604 comm="kadmind" src=756 scontext=unconfined_u:system_r:kadmind_t:s0 tcontext=system_u:object_r:hi_reserved_port_t:s0 tclass=tcp_socket
----

I'm sorry for the previous post of (looks like) unrelated AVCs. The related AVCs seem to be:
time->Thu Apr 14 10:32:59 2011
type=SYSCALL msg=audit(1302769979.125:149): arch=40000003 syscall=197 success=yes exit=0 a0=3 a1=bf841c1c a2=3ffff4 a3=2ae35f0 items=0 ppid=11730 pid=11732 auid=0 uid=23 gid=23 euid=23 suid=23 fsuid=23 egid=23 sgid=23 fsgid=23 tty=(none) ses=1 comm="squid_kerb_auth" exe="/usr/lib/squid/squid_kerb_auth" subj=unconfined_u:system_r:squid_t:s0 key=(null)
type=AVC msg=audit(1302769979.125:149): avc:  denied  { getattr } for  pid=11732 comm="squid_kerb_auth" path="/etc/selinux/config" dev=dm-0 ino=914485 scontext=unconfined_u:system_r:squid_t:s0 tcontext=system_u:object_r:selinux_config_t:s0 tclass=file
----
time->Thu Apr 14 10:32:59 2011
type=SYSCALL msg=audit(1302769979.518:150): arch=40000003 syscall=5 success=yes exit=3 a0=2ae34f0 a1=2c1 a2=180 a3=2c1 items=0 ppid=11730 pid=11732 auid=0 uid=23 gid=23 euid=23 suid=23 fsuid=23 egid=23 sgid=23 fsgid=23 tty=(none) ses=1 comm="squid_kerb_auth" exe="/usr/lib/squid/squid_kerb_auth" subj=unconfined_u:system_r:squid_t:s0 key=(null)
type=AVC msg=audit(1302769979.518:150): avc:  denied  { create } for  pid=11732 comm="squid_kerb_auth" name="HTTP_23" scontext=unconfined_u:system_r:squid_t:s0 tcontext=unconfined_u:object_r:tmp_t:s0 tclass=file
----
time->Thu Apr 14 10:32:59 2011
type=SYSCALL msg=audit(1302769979.124:148): arch=40000003 syscall=5 success=yes exit=3 a0=183255 a1=8000 a2=1b6 a3=1824d8 items=0 ppid=11730 pid=11732 auid=0 uid=23 gid=23 euid=23 suid=23 fsuid=23 egid=23 sgid=23 fsgid=23 tty=(none) ses=1 comm="squid_kerb_auth" exe="/usr/lib/squid/squid_kerb_auth" subj=unconfined_u:system_r:squid_t:s0 key=(null)
type=AVC msg=audit(1302769979.124:148): avc:  denied  { open } for  pid=11732 comm="squid_kerb_auth" name="config" dev=dm-0 ino=914485 scontext=unconfined_u:system_r:squid_t:s0 tcontext=system_u:object_r:selinux_config_t:s0 tclass=file
type=AVC msg=audit(1302769979.124:148): avc:  denied  { read } for  pid=11732 comm="squid_kerb_auth" name="config" dev=dm-0 ino=914485 scontext=unconfined_u:system_r:squid_t:s0 tcontext=system_u:object_r:selinux_config_t:s0 tclass=file

# getsebool allow_kerberos

allow_kerberos boolean is enabled on my testing machine:

# getsebool allow_kerberos
allow_kerberos --> on

Strange but I cannot reproduce the problems I had in comments 10 and 12 anymore. My test is now passing without denials.

# getenforce 
Enforcing
# semodule -l | grep mysquid
mysquid	1.2	
# cat ~/selinux/mysquid.te
policy_module(mysquid, 1.2)

require{
 type squid_t;
 type tmp_t;
}

kerberos_manage_host_rcache(squid_t)
allow squid_t tmp_t:dir rw_dir_perms;

I think this bug is now resolved, thanks everyone!

Miroslav I think we also need.

/var/tmp/HTTP_23		-- 	gen_context(system_u:object_r:krb5_host_rcache_t,s0)

Fixed in selinux-policy-3.7.19-86.el6

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2011-0526.html