tequilaOS/platform_system_sepolicy
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sepolicy: Clean up mls constraints.

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Require equivalence for all write operations.  We were already
doing this for app_data_file as a result of restricting open
rather than read/write, so this makes the model consistent across
all objects and operations.  It also addresses the scenario where
we have mixed usage of levelFrom=all and levelFrom=user for
different apps on the same device where the dominated-by (domby)
relation may not be sufficiently restrictive.

Drop the System V IPC constraints since System V IPC is never allowed
by TE and thus these constraints are dead policy.

Change-Id: Ic06a35030c086e3978c02d501c380889af8d21e0
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
This commit is contained in:
Stephen Smalley 2015-03-13 17:07:39 -04:00
parent eaece936f2
commit 025b7df298
1 changed files with 9 additions and 25 deletions
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34
mls
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@ -26,9 +26,9 @@ mlsconstrain process { transition dyntransition }
mlsconstrain process { getsched getsession getpgid getcap getattr ptrace share }
(l1 dom l2 or t1 == mlstrustedsubject);
# Process write operations: No write down unless trusted.
# Process write operations: Require equivalence unless trusted.
mlsconstrain process { sigkill sigstop signal setsched setpgid setcap setrlimit ptrace share }
(l1 domby l2 or t1 == mlstrustedsubject);
(l1 eq l2 or t1 == mlstrustedsubject);
#
# Socket constraints
@ -39,10 +39,10 @@ mlsconstrain process { sigkill sigstop signal setsched setpgid setcap setrlimit
mlsconstrain socket_class_set { create relabelfrom relabelto }
((h1 eq h2 and l1 eq l2) or t1 == mlstrustedsubject);
# Datagram send: Sender must be dominated by receiver unless one of them is
# trusted.
# Datagram send: Sender must be equivalent to the receiver unless one of them
# is trusted.
mlsconstrain unix_dgram_socket { sendto }
(l1 domby l2 or t1 == mlstrustedsubject or t2 == mlstrustedsubject);
(l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedsubject);
# Stream connect: Client must be equivalent to server unless one of them
# is trusted.
@ -83,13 +83,13 @@ mlsconstrain dir { read getattr search }
mlsconstrain { file lnk_file sock_file chr_file blk_file } { read getattr execute }
(t2 == app_data_file or l1 dom l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject);
# Write operations: Subject must be dominated by the object unless the
# Write operations: Subject must be equivalent to the object unless the
# subject or the object is trusted.
mlsconstrain dir { write setattr rename add_name remove_name reparent rmdir }
(t2 == app_data_file or l1 domby l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject);
(t2 == app_data_file or l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject);
mlsconstrain { file lnk_file sock_file chr_file blk_file } { write setattr append unlink link rename }
(t2 == app_data_file or l1 domby l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject);
(t2 == app_data_file or l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject);
# Special case for FIFOs.
# These can be unnamed pipes, in which case they will be labeled with the
@ -100,23 +100,7 @@ mlsconstrain fifo_file { read getattr }
(l1 dom l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject or t2 == domain);
mlsconstrain fifo_file { write setattr append unlink link rename }
(l1 domby l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject or t2 == domain);
#
# IPC constraints
#
# Create/destroy: equivalence or trusted.
mlsconstrain ipc_class_set { create destroy }
(l2 eq h2 and (l1 eq l2 or t1 == mlstrustedsubject));
# Read ops: No read up unless trusted.
mlsconstrain ipc_class_set r_ipc_perms
(l1 dom l2 or t1 == mlstrustedsubject);
# Write ops: No write down unless trusted.
mlsconstrain ipc_class_set w_ipc_perms
(l1 domby l2 or t1 == mlstrustedsubject);
(l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject or t2 == domain);
#
# Binder IPC constraints