public/ueventd.te

# ueventd seclabel is specified in init.rc since
# it lives in the rootfs and has no unique file type.
type ueventd, domain;

# Write to /dev/kmsg.
allow ueventd kmsg_device:chr_file rw_file_perms;

allow ueventd self:global_capability_class_set { chown mknod net_admin setgid fsetid sys_rawio dac_override fowner };
allow ueventd device:file create_file_perms;

r_dir_file(ueventd, rootfs)

# ueventd needs write access to files in /sys to regenerate uevents
allow ueventd sysfs_type:file w_file_perms;
r_dir_file(ueventd, sysfs_type)
allow ueventd sysfs_type:{ file lnk_file } { relabelfrom relabelto setattr };
allow ueventd sysfs_type:dir { relabelfrom relabelto setattr };
allow ueventd tmpfs:chr_file rw_file_perms;
allow ueventd dev_type:dir create_dir_perms;
allow ueventd dev_type:lnk_file { create unlink };
allow ueventd dev_type:chr_file { getattr create setattr unlink };
allow ueventd dev_type:blk_file { getattr relabelfrom relabelto create setattr unlink };
allow ueventd self:netlink_kobject_uevent_socket create_socket_perms_no_ioctl;
allow ueventd efs_file:dir search;
allow ueventd efs_file:file r_file_perms;

# Get SELinux enforcing status.
r_dir_file(ueventd, selinuxfs)

# Access for /vendor/ueventd.rc and /vendor/firmware
r_dir_file(ueventd, { vendor_file_type -vendor_app_file -vendor_overlay_file })

# Get file contexts for new device nodes
allow ueventd file_contexts_file:file r_file_perms;

# Use setfscreatecon() to label /dev directories and files.
allow ueventd self:process setfscreate;

# Allow ueventd to read androidboot.android_dt_dir from kernel cmdline.
allow ueventd proc_cmdline:file r_file_perms;

# Everything is labeled as rootfs in recovery mode. ueventd has to execute
# the dynamic linker and shared libraries.
recovery_only(`
  allow ueventd rootfs:file { r_file_perms execute };
')

# Suppress denials for ueventd to getattr /postinstall. This occurs when the
# linker tries to resolve paths in ld.config.txt.
dontaudit ueventd postinstall_mnt_dir:dir getattr;

# ueventd loads modules in response to modalias events.
allow ueventd self:global_capability_class_set sys_module;
allow ueventd vendor_file:system module_load;
allow ueventd kernel:key search;

#####
##### neverallow rules
#####

# ueventd must never set properties, otherwise deadlocks may occur.
# https://android-review.googlesource.com/#/c/133120/6/init/devices.cpp@941
# No writing to the property socket, connecting to init, or setting properties.
neverallow ueventd property_socket:sock_file write;
neverallow ueventd init:unix_stream_socket connectto;
neverallow ueventd property_type:property_service set;

# Restrict ueventd access on block devices to maintenence operations.
neverallow ueventd dev_type:blk_file ~{ getattr relabelfrom relabelto create setattr unlink };

# Only relabelto as we would never want to relabelfrom kmem_device or port_device
neverallow ueventd { kmem_device port_device }:chr_file ~{ getattr create setattr unlink relabelto };

# Nobody should be able to ptrace ueventd
neverallow * ueventd:process ptrace;