From c6fe53a995d7b9bf6e89a172f2453f777310e7b8 Mon Sep 17 00:00:00 2001
From: CN_SZTL <cnsztl@gmail.com>
Date: Wed, 15 Jan 2020 02:00:14 +0800
Subject: [PATCH] buildsystem: Make PIE ASLR option tristate

---
 config/Config-build.in | 22 ++++++++++++++++++----
 include/hardening.mk   |  9 ++++++++-
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/config/Config-build.in b/config/Config-build.in
index 3468f205cd..0eef645f3c 100644
--- a/config/Config-build.in
+++ b/config/Config-build.in
@@ -195,11 +195,10 @@ menu "Global build settings"
 		  this per package by adding PKG_CHECK_FORMAT_SECURITY:=0 in the package
 		  Makefile.
 
-	config PKG_ASLR_PIE
-		bool
+	choice
 		prompt "User space ASLR PIE compilation"
-		select BUSYBOX_DEFAULT_PIE
-		default n
+		default PKG_ASLR_PIE_NONE if ((SMALL_FLASH || LOW_MEMORY_FOOTPRINT) && !SDK)
+		default PKG_ASLR_PIE_REGULAR
 		help
 		  Add -fPIC to CFLAGS and -specs=hardened-build-ld to LDFLAGS.
 		  This enables package build as Position Independent Executables (PIE)
@@ -210,6 +209,21 @@ menu "Global build settings"
 		  to predict when an attacker is attempting a memory-corruption exploit.
 		  You can disable this per package by adding PKG_ASLR_PIE:=0 in the package
 		  Makefile.
+		  Be ware that ASLR increases the binary size.
+		config PKG_ASLR_PIE_NONE
+			bool "None"
+			help
+			  PIE is deactivated for all applications
+		config PKG_ASLR_PIE_REGULAR
+			bool "Regular"
+			help
+			  PIE is activated for some binaries, mostly network exposed applications
+		config PKG_ASLR_PIE_ALL
+			bool "All"
+			select BUSYBOX_DEFAULT_PIE
+			help
+			  PIE is activated for all applications
+	endchoice
 
 	choice
 		prompt "User space Stack-Smashing Protection"
diff --git a/include/hardening.mk b/include/hardening.mk
index 60f39428e8..4e49e6b1b9 100644
--- a/include/hardening.mk
+++ b/include/hardening.mk
@@ -7,6 +7,7 @@
 
 PKG_CHECK_FORMAT_SECURITY ?= 1
 PKG_ASLR_PIE ?= 1
+PKG_ASLR_PIE_REGULAR ?= 0
 PKG_SSP ?= 1
 PKG_FORTIFY_SOURCE ?= 1
 PKG_RELRO ?= 1
@@ -16,12 +17,18 @@ ifdef CONFIG_PKG_CHECK_FORMAT_SECURITY
     TARGET_CFLAGS += -Wformat -Werror=format-security
   endif
 endif
-ifdef CONFIG_PKG_ASLR_PIE
+ifdef CONFIG_PKG_ASLR_PIE_ALL
   ifeq ($(strip $(PKG_ASLR_PIE)),1)
     TARGET_CFLAGS += $(FPIC)
     TARGET_LDFLAGS += $(FPIC) -specs=$(INCLUDE_DIR)/hardened-ld-pie.specs
   endif
 endif
+ifdef CONFIG_PKG_ASLR_PIE_REGULAR
+  ifeq ($(strip $(PKG_ASLR_PIE_REGULAR)),1)
+    TARGET_CFLAGS += $(FPIC)
+    TARGET_LDFLAGS += $(FPIC) -specs=$(INCLUDE_DIR)/hardened-ld-pie.specs
+  endif
+endif
 ifdef CONFIG_PKG_CC_STACKPROTECTOR_REGULAR
   ifeq ($(strip $(PKG_SSP)),1)
     TARGET_CFLAGS += -fstack-protector