Add microdroid specific sepolicy
Microdroid will have a separate sepolicy, apart from the core policy.
This is the first step; For now it's a simple copy of system/sepolicy.
For the future work, it will be stripped.
Bug: 189165759
Test: boot microdroid and see selinux enforced
Change-Id: I2fee39f7231560b49c93bd5e8d0feeffada40938
diff --git a/microdroid/sepolicy/system/public/netd.te b/microdroid/sepolicy/system/public/netd.te
new file mode 100644
index 0000000..ff0bff6
--- /dev/null
+++ b/microdroid/sepolicy/system/public/netd.te
@@ -0,0 +1,176 @@
+# network manager
+type netd, domain, mlstrustedsubject;
+type netd_exec, system_file_type, exec_type, file_type;
+
+net_domain(netd)
+# in addition to ioctls allowlisted for all domains, grant netd priv_sock_ioctls.
+allowxperm netd self:udp_socket ioctl priv_sock_ioctls;
+
+r_dir_file(netd, cgroup)
+
+allow netd system_server:fd use;
+
+allow netd self:global_capability_class_set { net_admin net_raw kill };
+# Note: fsetid is deliberately not included above. fsetid checks are
+# triggered by chmod on a directory or file owned by a group other
+# than one of the groups assigned to the current process to see if
+# the setgid bit should be cleared, regardless of whether the setgid
+# bit was even set. We do not appear to truly need this capability
+# for netd to operate.
+dontaudit netd self:global_capability_class_set fsetid;
+
+# Allow netd to open /dev/tun, set it up and pass it to clatd
+allow netd tun_device:chr_file rw_file_perms;
+allowxperm netd tun_device:chr_file ioctl { TUNGETIFF TUNSETIFF };
+allow netd self:tun_socket create;
+
+allow netd self:netlink_kobject_uevent_socket create_socket_perms_no_ioctl;
+allow netd self:netlink_route_socket nlmsg_write;
+allow netd self:netlink_nflog_socket create_socket_perms_no_ioctl;
+allow netd self:netlink_socket create_socket_perms_no_ioctl;
+allow netd self:netlink_tcpdiag_socket { create_socket_perms_no_ioctl nlmsg_read nlmsg_write };
+allow netd self:netlink_generic_socket create_socket_perms_no_ioctl;
+allow netd self:netlink_netfilter_socket create_socket_perms_no_ioctl;
+allow netd shell_exec:file rx_file_perms;
+allow netd system_file:file x_file_perms;
+not_full_treble(`allow netd vendor_file:file x_file_perms;')
+allow netd devpts:chr_file rw_file_perms;
+
+# Acquire advisory lock on /system/etc/xtables.lock. If this file doesn't
+# exist, suppress the denial.
+allow netd system_file:file lock;
+dontaudit netd system_file:dir write;
+
+# Allow netd to write to qtaguid ctrl file.
+# TODO: Add proper rules to prevent other process to access qtaguid_proc file
+# after migration complete
+allow netd proc_qtaguid_ctrl:file rw_file_perms;
+# Allow netd to read /dev/qtaguid. This is the same privilege level that normal apps have.
+allow netd qtaguid_device:chr_file r_file_perms;
+
+r_dir_file(netd, proc_net_type)
+# For /proc/sys/net/ipv[46]/route/flush.
+allow netd proc_net_type:file rw_file_perms;
+
+# Enables PppController and interface enumeration (among others)
+allow netd sysfs:dir r_dir_perms;
+r_dir_file(netd, sysfs_net)
+
+# Allows setting interface MTU
+allow netd sysfs_net:file w_file_perms;
+
+# TODO: added to match above sysfs rule. Remove me?
+allow netd sysfs_usb:file write;
+
+r_dir_file(netd, cgroup_v2)
+
+allow netd fs_bpf:dir search;
+allow netd fs_bpf:file { read write };
+
+# TODO: netd previously thought it needed these permissions to do WiFi related
+# work. However, after all the WiFi stuff is gone, we still need them.
+# Why?
+allow netd self:global_capability_class_set { dac_override dac_read_search chown };
+
+# Needed to update /data/misc/net/rt_tables
+allow netd net_data_file:file create_file_perms;
+allow netd net_data_file:dir rw_dir_perms;
+allow netd self:global_capability_class_set fowner;
+
+# Needed to lock the iptables lock.
+allow netd system_file:file lock;
+
+# Allow netd to spawn dnsmasq in it's own domain
+allow netd dnsmasq:process signal;
+
+# Allow netd to publish a binder service and make binder calls.
+binder_use(netd)
+add_service(netd, netd_service)
+add_service(netd, dnsresolver_service)
+allow netd dumpstate:fifo_file { getattr write };
+
+# Allow netd to call into the system server so it can check permissions.
+allow netd system_server:binder call;
+allow netd permission_service:service_manager find;
+
+# Allow netd to talk to the framework service which collects netd events.
+allow netd netd_listener_service:service_manager find;
+
+# Allow netd to operate on sockets that are passed to it.
+allow netd netdomain:{
+ icmp_socket
+ tcp_socket
+ udp_socket
+ rawip_socket
+ tun_socket
+} { read write getattr setattr getopt setopt };
+allow netd netdomain:fd use;
+
+# give netd permission to read and write netlink xfrm
+allow netd self:netlink_xfrm_socket { create_socket_perms_no_ioctl nlmsg_write nlmsg_read };
+
+# Allow netd to register as hal server.
+add_hwservice(netd, system_net_netd_hwservice)
+hwbinder_use(netd)
+
+###
+### Neverallow rules
+###
+### netd should NEVER do any of this
+
+# Block device access.
+neverallow netd dev_type:blk_file { read write };
+
+# ptrace any other app
+neverallow netd { domain }:process ptrace;
+
+# Write to /system.
+neverallow netd system_file:dir_file_class_set write;
+
+# Write to files in /data/data or system files on /data
+neverallow netd { app_data_file_type system_data_file }:dir_file_class_set write;
+
+# only system_server, dumpstate and network stack app may find netd service
+neverallow {
+ domain
+ -system_server
+ -dumpstate
+ -network_stack
+ -netd
+ -netutils_wrapper
+} netd_service:service_manager find;
+
+# only system_server, dumpstate and network stack app may find dnsresolver service
+neverallow {
+ domain
+ -system_server
+ -dumpstate
+ -network_stack
+ -netd
+ -netutils_wrapper
+} dnsresolver_service:service_manager find;
+
+# apps may not interact with netd over binder.
+neverallow { appdomain -network_stack } netd:binder call;
+neverallow netd { appdomain -network_stack userdebug_or_eng(`-su') }:binder call;
+
+# If an already existing file is opened with O_CREATE, the kernel might generate
+# a false report of a create denial. Silence these denials and make sure that
+# inappropriate permissions are not granted.
+neverallow netd proc_net:dir no_w_dir_perms;
+dontaudit netd proc_net:dir write;
+
+neverallow netd sysfs_net:dir no_w_dir_perms;
+dontaudit netd sysfs_net:dir write;
+
+# Netd should not have SYS_ADMIN privs.
+neverallow netd self:capability sys_admin;
+dontaudit netd self:capability sys_admin;
+
+# Netd should not have SYS_MODULE privs, nor should it be requesting module loads
+# (things it requires should be built directly into the kernel)
+dontaudit netd self:capability sys_module;
+
+dontaudit netd kernel:system module_request;
+
+dontaudit netd appdomain:unix_stream_socket { read write };