ASAN-Extract

Add init script and shell script to unzip a tar containing ASAN
libraries on boot.

Bug: 36458146
Test: m && m SANITIZE_TARGET=address
Test: manual (build steps for tar missing)
Change-Id: I1bcf332f86c5bf2e0333cbe3def684999c1002f8

rootdir/Android.mk

@@ -101,6 +101,21 @@ ifneq ($(SANITIZE_ASAN_OPTIONS_FOR),)
   $(foreach binary, $(SANITIZE_ASAN_OPTIONS_FOR), $(eval $(call create-asan-options-module,$(binary))))
 endif
 
+# ASAN extration.
+ASAN_EXTRACT_FILES :=
+ifeq ($(SANITIZE_TARGET_SYSTEM),true)
+include $(CLEAR_VARS)
+LOCAL_MODULE:= asan_extract
+LOCAL_MODULE_TAGS := optional
+LOCAL_MODULE_CLASS := EXECUTABLES
+LOCAL_SRC_FILES := asan_extract.sh
+LOCAL_INIT_RC := asan_extract.rc
+# We need bzip2 on device for extraction.
+LOCAL_REQUIRED_MODULES := bzip2
+include $(BUILD_PREBUILT)
+ASAN_EXTRACT_FILES := asan_extract
+endif
+
 endif
 
 #######################################
@@ -114,7 +129,7 @@ LOCAL_MODULE_PATH := $(TARGET_ROOT_OUT)
 EXPORT_GLOBAL_ASAN_OPTIONS :=
 ifneq ($(filter address,$(SANITIZE_TARGET)),)
   EXPORT_GLOBAL_ASAN_OPTIONS := export ASAN_OPTIONS include=/system/asan.options
-  LOCAL_REQUIRED_MODULES := asan.options $(ASAN_OPTIONS_FILES)
+  LOCAL_REQUIRED_MODULES := asan.options $(ASAN_OPTIONS_FILES) $(ASAN_EXTRACT_FILES)
 endif
 
 EXPORT_GLOBAL_GCOV_OPTIONS :=

rootdir/asan_extract.rc

@@ -0,0 +1,6 @@
+# When /data is available, look for /system/asan.tar.gz and potentially extract.
+on post-fs-data
+    exec - system system -- /system/bin/asan_extract
+
+on early-boot && property:asan.restore_reboot=1
+    powerctl reboot

rootdir/asan_extract.sh

@@ -0,0 +1,66 @@
+#!/system/bin/sh
+
+#
+# Copyright (C) 2017 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# This script will extract ASAN libraries from /system/asan.tar.gz to /data and then reboot.
+
+# TODO:
+#   * Timestamp or something to know when to run this again. Right now take the existence of
+#     /data/lib as we're already done.
+#   * Need to distinguish pre- from post-decryption for FDE.
+
+SRC=/system/asan.tar.bz2
+MD5_FILE=/data/asan.md5sum
+
+if ! test -f $SRC ; then
+  log -p i -t asan_install "Did not find $SRC!"
+  exit 1
+fi
+
+log -p i -t asan_install "Found $SRC, checking whether we need to apply it."
+
+ASAN_TAR_MD5=$(md5sum $SRC)
+if test -f $MD5_FILE ; then
+  INSTALLED_MD5=$(cat $MD5_FILE)
+  if [ "x$ASAN_TAR_MD5" = "x$INSTALLED_MD5" ] ; then
+    log -p i -t asan_install "Checksums match, nothing to be done here."
+    exit 0
+  fi
+fi
+
+# Just clean up, helps with restorecon.
+rm -rf /data/lib /data/lib64 /data/vendor/lib*
+
+log -p i -t asan_install "Untarring $SRC..."
+
+# Unzip from /system/asan.tar.gz into data. Need to pipe as gunzip is not on device.
+bzip2 -c -d $SRC | tar -x -f - --no-same-owner -C / || exit 1
+
+# Cannot log here, log would run with system_data_file.
+
+restorecon -R -F /data/lib* /data/vendor/lib*
+
+log -p i -t asan_install "Fixed selinux labels..."
+
+echo "$ASAN_TAR_MD5" > $MD5_FILE
+
+# We want to reboot now. It seems it is not possible to run "reboot" here, the device will
+# just be stuck.
+
+log -p i -t asan_install "Signaling init to reboot..."
+
+setprop asan.restore_reboot 1