platform_system_sepolicy/unconfined.te
Stephen Smalley 04ee5dfb80 Remove MAC capabilities from unconfined domains.
Linux defines two capabilities for Mandatory Access Control (MAC)
security modules, CAP_MAC_OVERRIDE (override MAC access restrictions)
and CAP_MAC_ADMIN (allow MAC configuration or state changes).
SELinux predates these capabilities and did not originally use them,
but later made use of CAP_MAC_ADMIN as a way to control the ability
to set security context values unknown to the currently loaded
SELinux policy on files.  That facility is used in Linux for e.g.
livecd creation where a file security context that is being set
on a generated filesystem is not known to the build host policy.
Internally, files with such labels are treated as having the unlabeled
security context for permission checking purposes until/unless the
context is later defined through a policy reload.

CAP_MAC_OVERRIDE is never checked by SELinux, so it never needs
to be allowed.  CAP_MAC_ADMIN is only checked if setting an
unknown security context value; the only legitimate use I can see
in Android is the recovery console, where a context may need to be set
on /system that is not defined in the recovery policy.

Remove these capabilities from unconfined domains, allow
mac_admin for the recovery domain, and add neverallow rules.

Change-Id: Ief673e12bc3caf695f3fb67cabe63e68f5f58150
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
2014-01-30 14:36:57 -05:00

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2.4 KiB
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#######################################################
#
# This is the unconfined template. This template is the base policy
# which is used by daemons and other privileged components of
# Android.
#
# Historically, this template was called "unconfined" because it
# allowed the domain to do anything it wanted. Over time,
# this has changed, and will continue to change in the future.
# The rules in this file will be removed when no remaining
# unconfined domains require it, or when the rules contradict
# Android security best practices. Domains which need rules not
# provided by the unconfined template should add them directly to
# the relevant policy.
#
# The use of this template is discouraged.
######################################################
allow unconfineddomain self:capability *;
allow unconfineddomain self:capability2 ~{ mac_override mac_admin };
allow unconfineddomain kernel:security ~{ load_policy setenforce setcheckreqprot };
allow unconfineddomain kernel:system *;
allow unconfineddomain domain:process ~{ execmem execstack execheap ptrace transition dyntransition };
allow unconfineddomain domain:fd *;
allow unconfineddomain domain:dir r_dir_perms;
allow unconfineddomain domain:lnk_file r_file_perms;
allow unconfineddomain domain:{ fifo_file file } rw_file_perms;
allow unconfineddomain domain:socket_class_set *;
allow unconfineddomain domain:ipc_class_set *;
allow unconfineddomain domain:key *;
allow unconfineddomain fs_type:filesystem *;
allow unconfineddomain {fs_type dev_type file_type}:{ dir blk_file lnk_file sock_file fifo_file } ~relabelto;
allow unconfineddomain {fs_type -usermodehelper -proc_security}:{ chr_file file } ~{entrypoint execmod execute relabelto};
allow unconfineddomain {dev_type -kmem_device}:{ chr_file file } ~{entrypoint execmod execute relabelto};
allow unconfineddomain file_type:{ chr_file file } ~{entrypoint execmod execute relabelto};
allow unconfineddomain { rootfs system_file exec_type }:file execute;
allow unconfineddomain node_type:node *;
allow unconfineddomain node_type:{ tcp_socket udp_socket rawip_socket } node_bind;
allow unconfineddomain netif_type:netif *;
allow unconfineddomain port_type:socket_class_set name_bind;
allow unconfineddomain port_type:{ tcp_socket dccp_socket } name_connect;
allow unconfineddomain domain:peer recv;
allow unconfineddomain { domain -init }:binder { call transfer set_context_mgr };
allow unconfineddomain property_type:property_service set;