Courier IMAPd related policy changes

PATCH New Sven Vermeulen 2 participants 10 messages Dec 31, 2014 – Jan 1, 2015

lore

Share & tools

lore

Sven Vermeulen

author

2014-12-31 16:09 UTC #0 lore raw

v2 cover Courier IMAPd related policy changes

Small updates to courier policy in order to have the Courier IMAPd work with the policy.

Changes since v1:
- add file contexts for imapd.pid and imapd.pid.lock
- use courier_var_lib_t in stream_connect pattern
- drop user content access for courier now that there is mail_home_rw_t access

Sven Vermeulen (6):
Courier TCPd startup creates imapd.pid.lock and imapd.lock Locate authdaemon socket and communicate with authdaemon Allow authdaemon to access selinux fs to check SELinux state Grant setuid/setgid to courier_pop_t
Execute courier helper script after authentication Courier IMAP needs to manage the users' maildir

 courier.fc |  2 ++
 courier.te | 12 ++++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

Signature · 1 line

2.0.5

Sven Vermeulen

author

2014-12-31 16:09 UTC #1 lore raw

PATCH v2 1/6 Courier TCPd startup creates imapd.pid.lock and imapd.lock

Startup of courier-imapd creates /var/run/imapd.pid.lock and imapd.lock

Signed-off-by Sven Vermeulen <[email protected]>

---
 courier.fc | 2 ++
 courier.te | 2 ++
 2 files changed, 4 insertions(+)

courier.fc +2 -0

index 2f017a0..abdc37e 100644
@@ -27,6 +27,8 @@
 /var/lib/courier-imap(/.*)?	gen_context(system_u:object_r:courier_var_lib_t,s0)
 
 /var/run/courier(/.*)?	gen_context(system_u:object_r:courier_var_run_t,s0)
+/var/run/imapd\.pid	--	gen_context(system_u:object_r:courier_var_run_t,s0)
+/var/run/imapd\.pid\.lock	--	gen_context(system_u:object_r:courier_var_run_t,s0)
 
 /var/spool/authdaemon(/.*)?	gen_context(system_u:object_r:courier_spool_t,s0)
 /var/spool/courier(/.*)?	gen_context(system_u:object_r:courier_spool_t,s0)

courier.te +2 -0

index ae3bc70..112a60b 100644
@@ -172,6 +172,8 @@ corenet_tcp_sendrecv_pop_port(courier_tcpd_t)
 dev_read_rand(courier_tcpd_t)
 dev_read_urand(courier_tcpd_t)
 
+files_pid_filetrans(courier_tcpd_t, courier_var_run_t, file)
+
 miscfiles_read_localization(courier_tcpd_t)
 
 ########################################

Signature · 1 line

2.0.5

Dominick Grift

2015-01-01 17:41 UTC #2 lore raw

PATCH v2 1/6 Courier TCPd startup creates imapd.pid.lock and imapd.lock

Quoted 13 lines · Sven Vermeulen

Startup of courier-imapd creates /var/run/imapd.pid.lock and imapd.lock
Signed-off-by Sven Vermeulen <[email protected]>
---
 courier.fc | 2 ++
 courier.te | 2 ++
 2 files changed, 4 insertions(+)
courier.fc +0 -0
index 2f017a0..abdc37e 100644

courier.fc line 30

Quoted 4 lines

courier.fc +1 -0

@@ -27,6 +27,8 @@
 /var/lib/courier-imap(/.*)?	gen_context(system_u:object_r:courier_var_lib_t,s0)
 
 /var/run/courier(/.*)?	gen_context(system_u:object_r:courier_var_run_t,s0)
+/var/run/imapd\.pid	--	gen_context(system_u:object_r:courier_var_run_t,s0)

This conflicts with uwimap pid file context specification

Not sure how to deal with this, but i would prefer:

Did you build with: --with-piddir=dir - use dir/imapd.pid to store couriertcpd's process ID.

Probably better to set --with-piddir=/var/run/courier

That will make this patch redundant

Quoted 24 lines

courier.fc +1 -0

+/var/run/imapd\.pid\.lock	--	gen_context(system_u:object_r:courier_var_run_t,s0)
 
 /var/spool/authdaemon(/.*)?	gen_context(system_u:object_r:courier_spool_t,s0)
 /var/spool/courier(/.*)?	gen_context(system_u:object_r:courier_spool_t,s0)

courier.te +2 -0

index ae3bc70..112a60b 100644
@@ -172,6 +172,8 @@ corenet_tcp_sendrecv_pop_port(courier_tcpd_t)
 dev_read_rand(courier_tcpd_t)
 dev_read_urand(courier_tcpd_t)
 
+files_pid_filetrans(courier_tcpd_t, courier_var_run_t, file)
+
 miscfiles_read_localization(courier_tcpd_t)
 
 ########################################

Signature · 6 lines

2.0.5

_______________________________________________
refpolicy mailing list
refpolicy at oss.tresys.com
http://oss.tresys.com/mailman/listinfo/refpolicy

Signature · 8 lines

Dominick Grift
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 648 bytes
Desc: not available
Url : http://oss.tresys.com/pipermail/refpolicy/attachments/20150101/26b55a01/attachment.bin

Sven Vermeulen

author

2014-12-31 16:09 UTC #3 lore raw

PATCH v2 2/6 Locate authdaemon socket and communicate with authdaemon

In reply to Sven Vermeulen

Without this, authentication fails. The following is shown in the logs:

Dec 30 19:36:54 localhost imapd: Connection, ip=[::ffff:192.168.100.152]
Dec 30 19:36:54 localhost imapd: authdaemon: s_connect() failed: Permission denied
Dec 30 19:36:54 localhost imapd: LOGIN FAILED, user=root, ip=[::ffff:192.168.100.152]
Dec 30 19:36:54 localhost imapd: authentication error: Permission denied

Through logon, the daemon (courier_pop_t) wants to locate the socket in /var/lib/courier to initiate communication with the authdaemon.

Signed-off-by Sven Vermeulen <[email protected]>

---
 courier.te | 2 ++
 1 file changed, 2 insertions(+)

courier.te +2 -0

index 112a60b..b12dd7f 100644
@@ -137,6 +137,8 @@ allow courier_pop_t courier_tcpd_t:{ unix_stream_socket tcp_socket } rw_stream_s
 
 allow courier_pop_t courier_var_lib_t:file { read write };
 
+stream_connect_pattern(courier_pop_t, courier_var_lib_t, courier_var_lib_t, courier_authdaemon_t)
+
 domtrans_pattern(courier_pop_t, courier_authdaemon_exec_t, courier_authdaemon_t)
 
 miscfiles_read_localization(courier_pop_t)

Signature · 1 line

2.0.5

Sven Vermeulen

author

2014-12-31 16:09 UTC #4 lore raw

PATCH v2 3/6 Allow authdaemon to access selinux fs to check SELinux state

In reply to Sven Vermeulen

When attempting to authenticate, the PAM module checks if SELinux is enabled (pam_unix, in order to verify if the chkpwd helper utility needs to be called). If it fails to check the SELinux state, then authdaemon will try to access shadow directly (again, through pam_unix).

This only occurs when a user tries to log on as root (on IMAP server) as non-root users automatically have chkpwd executed.

Signed-off-by Sven Vermeulen <[email protected]>

---
 courier.te | 2 ++
 1 file changed, 2 insertions(+)

courier.te +2 -0

index b12dd7f..b46eada 100644
@@ -114,6 +114,8 @@ libs_read_lib_files(courier_authdaemon_t)
 
 miscfiles_read_localization(courier_authdaemon_t)
 
+selinux_getattr_fs(courier_authdaemon_t)
+
 userdom_dontaudit_search_user_home_dirs(courier_authdaemon_t)
 
 ########################################

Signature · 1 line

2.0.5

Sven Vermeulen

author

2014-12-31 16:09 UTC #5 lore raw

PATCH v2 4/6 Grant setuid/setgid to courier_pop_t

In reply to Sven Vermeulen

When trying to log on to the IMAP service, the authentication fails and the following shows up in the courier logs:

Dec 30 19:40:56 localhost imapd: Connection, ip=[::ffff:192.168.100.152]
Dec 30 19:40:56 localhost imapd: initgroups: Operation not permitted

In the audit logs, the following shows up:

type=AVC msg=audit(1419968456.850:190): avc: denied { setgid } for pid=4028 comm="imaplogin" capability=6 scontext=system_u:system_r:courier_pop_t:s0 tcontext=system_u:system_r:courier_pop_t:s0 tclass=capability

type=AVC msg=audit(1419968532.622:192): avc: denied { setuid } for pid=4118 comm="imaplogin" capability=7 scontext=system_u:system_r:courier_pop_t:s0 tcontext=system_u:system_r:courier_pop_t:s0 tclass=capability

The daemon wants to switch user to access the necessary maildir's.

Signed-off-by Sven Vermeulen <[email protected]>

---
 courier.te | 1 +
 1 file changed, 1 insertion(+)

courier.te +1 -0

index b46eada..7967fc6 100644
@@ -132,6 +132,7 @@ dev_read_rand(courier_pcp_t)
 # POP3/IMAP local policy
 #
 
+allow courier_pop_t self:capability { setgid setuid };
 allow courier_pop_t courier_authdaemon_t:tcp_socket rw_stream_socket_perms;
 allow courier_pop_t courier_authdaemon_t:process sigchld;

Signature · 1 line

2.0.5

Sven Vermeulen

author

2014-12-31 16:09 UTC #6 lore raw

PATCH v2 5/6 Execute courier helper script after authentication

In reply to Sven Vermeulen

After succesful authentication, the IMAP daemon will attempt to execute a helper script called /usr/lib64/courier-imap/courier-imapd.indirect. This helper script is to initiate the user session.

Signed-off-by Sven Vermeulen <[email protected]>

---
 courier.te | 2 ++
 1 file changed, 2 insertions(+)

courier.te +2 -0

index 7967fc6..6053939 100644
@@ -144,6 +144,8 @@ stream_connect_pattern(courier_pop_t, courier_var_lib_t, courier_var_lib_t, cour
 
 domtrans_pattern(courier_pop_t, courier_authdaemon_exec_t, courier_authdaemon_t)
 
+corecmd_exec_shell(courier_pop_t)
+
 miscfiles_read_localization(courier_pop_t)
 
 userdom_manage_user_home_content_files(courier_pop_t)

Signature · 1 line

2.0.5

Sven Vermeulen

author

2014-12-31 16:09 UTC #7 lore raw

PATCH v2 6/6 Courier IMAP needs to manage the users' maildir

In reply to Sven Vermeulen

Without these permissions, the logon immediately terminates and the following shows up in the logs:

Dec 30 19:45:33 localhost imapd: Connection, ip=[::ffff:192.168.100.152]
Dec 30 19:45:33 localhost imapd: chdir .maildir: Permission denied
Dec 30 19:45:33 localhost imapd: root: Permission denied

The first denial (and many similar ones follow when granted):

type=AVC msg=audit(1419968733.163:197): avc: denied { search } for pid=4292 comm="courier-imapd" name=".maildir" dev="vda3" ino=393221 scontext=system_u:system_r:courier_pop_t:s0 tcontext=root:object_r:mail_home_rw_t:s0 tclass=dir

Signed-off-by Sven Vermeulen <[email protected]>

---
 courier.te | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

courier.te +1 -2

index 6053939..91c0ee8 100644
@@ -148,8 +148,7 @@ corecmd_exec_shell(courier_pop_t)
 
 miscfiles_read_localization(courier_pop_t)
 
-userdom_manage_user_home_content_files(courier_pop_t)
-userdom_manage_user_home_content_dirs(courier_pop_t)
+mta_manage_mail_home_rw_content(courier_pop_t)
 
 ########################################
 #

Signature · 1 line

2.0.5

Dominick Grift

2014-12-31 18:00 UTC #8 lore raw

v2 cover Courier IMAPd related policy changes

In reply to Sven Vermeulen

Quoted 1 line · Sven Vermeulen

Small updates to courier policy in order to have the Courier IMAPd work with the policy.

There is an issue with the tresys mail list. It does not relay all messages

This one did not make it to you i suspect:

http://oss.tresys.com/pipermail/refpolicy/2014-December/007541.html

Quoted 25 lines

Changes since v1:
- add file contexts for imapd.pid and imapd.pid.lock
- use courier_var_lib_t in stream_connect pattern
- drop user content access for courier now that there is mail_home_rw_t access
Sven Vermeulen (6):
Courier TCPd startup creates imapd.pid.lock and imapd.lock Locate authdaemon socket and communicate with authdaemon Allow authdaemon to access selinux fs to check SELinux state Grant setuid/setgid to courier_pop_t
Execute courier helper script after authentication Courier IMAP needs to manage the users' maildir
 courier.fc |  2 ++
 courier.te | 12 ++++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)
Signature · 6 lines
2.0.5

_______________________________________________
refpolicy mailing list
refpolicy at oss.tresys.com
http://oss.tresys.com/mailman/listinfo/refpolicy

Signature · 8 lines

Dominick Grift
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 648 bytes
Desc: not available
Url : http://oss.tresys.com/pipermail/refpolicy/attachments/20141231/b7d069a8/attachment-0001.bin

Dominick Grift

2015-01-01 18:29 UTC #9 lore raw

v2 cover Courier IMAPd related policy changes

In reply to Sven Vermeulen

Quoted 1 line · Sven Vermeulen

Small updates to courier policy in order to have the Courier IMAPd work with the policy.

Thanks. This set was merged except for patch 1/6 because it is redundant when you build courier with "with-piddir=/var/run/courier/"

If you don't then /var/run/imapd.pid conflicts uwimaps' /var/run/imapd.pid

Quoted 25 lines

Changes since v1:
- add file contexts for imapd.pid and imapd.pid.lock
- use courier_var_lib_t in stream_connect pattern
- drop user content access for courier now that there is mail_home_rw_t access
Sven Vermeulen (6):
Courier TCPd startup creates imapd.pid.lock and imapd.lock Locate authdaemon socket and communicate with authdaemon Allow authdaemon to access selinux fs to check SELinux state Grant setuid/setgid to courier_pop_t
Execute courier helper script after authentication Courier IMAP needs to manage the users' maildir
 courier.fc |  2 ++
 courier.te | 12 ++++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)
Signature · 6 lines
2.0.5

_______________________________________________
refpolicy mailing list
refpolicy at oss.tresys.com
http://oss.tresys.com/mailman/listinfo/refpolicy

Signature · 8 lines

Dominick Grift
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 648 bytes
Desc: not available
Url : http://oss.tresys.com/pipermail/refpolicy/attachments/20150101/e6f7c6e6/attachment.bin