Separate fsck domains to protect userdata.
Create new vold_fsck domain that only has access to vold_block
devices to prevent any access to internal userdata.
Change-Id: I25ddcd16cbf83d7a25b70bc64d95f5345d0d5731
diff --git a/fsck.te b/fsck.te
index a86884c..6a3d1ee 100644
--- a/fsck.te
+++ b/fsck.te
@@ -1,4 +1,4 @@
-# Any fsck program run by init or vold
+# Any fsck program run by init
type fsck, domain;
type fsck_exec, exec_type, file_type;
@@ -15,11 +15,6 @@
allow fsck block_device:dir search;
allow fsck userdata_block_device:blk_file rw_file_perms;
allow fsck cache_block_device:blk_file rw_file_perms;
-allow fsck vold_device:blk_file rw_file_perms;
-
-# Allow stdin/out back to vold
-allow fsck vold:fd use;
-allow fsck vold:fifo_file { read write getattr };
###
### neverallow rules
@@ -34,9 +29,10 @@
root_block_device
swap_block_device
system_block_device
+ vold_device
}:blk_file no_rw_file_perms;
-# Only allow entry from init or vold via fsck binaries
-neverallow { domain -init -vold } fsck:process transition;
+# Only allow entry from init via fsck binaries
+neverallow { domain -init } fsck:process transition;
neverallow domain fsck:process dyntransition;
neverallow fsck { file_type fs_type -fsck_exec }:file entrypoint;
diff --git a/vold.te b/vold.te
index cde7c77..0a42b2d 100644
--- a/vold.te
+++ b/vold.te
@@ -8,7 +8,7 @@
domain_auto_trans(vold, sgdisk_exec, sgdisk);
domain_auto_trans(vold, blkid_exec, blkid);
domain_auto_trans(vold, sdcardd_exec, sdcardd);
-domain_auto_trans(vold, fsck_exec, fsck);
+domain_auto_trans(vold, fsck_exec, vold_fsck);
typeattribute vold mlstrustedsubject;
allow vold self:process setfscreate;
diff --git a/vold_fsck.te b/vold_fsck.te
new file mode 100644
index 0000000..e45c527
--- /dev/null
+++ b/vold_fsck.te
@@ -0,0 +1,35 @@
+# Any fsck program run by vold
+type vold_fsck, domain;
+
+# Inherit and use pty created by android_fork_execvp_ext().
+allow vold_fsck devpts:chr_file { read write ioctl getattr };
+
+# Run fsck on certain block devices
+allow vold_fsck block_device:dir search;
+allow vold_fsck vold_device:blk_file rw_file_perms;
+
+# Allow stdin/out back to vold
+allow vold_fsck vold:fd use;
+allow vold_fsck vold:fifo_file { read write getattr };
+
+###
+### neverallow rules
+###
+
+# fsck should never be run on these block devices
+neverallow vold_fsck {
+ boot_block_device
+ frp_block_device
+ metadata_block_device
+ recovery_block_device
+ root_block_device
+ swap_block_device
+ system_block_device
+ userdata_block_device
+ cache_block_device
+}:blk_file no_rw_file_perms;
+
+# Only allow entry from vold via fsck binaries
+neverallow { domain -vold } vold_fsck:process transition;
+neverallow domain vold_fsck:process dyntransition;
+neverallow vold_fsck { file_type fs_type -fsck_exec }:file entrypoint;