From 491f3fc048c0a8c1b55019a3f45684cc252408d5 Mon Sep 17 00:00:00 2001 From: John Crispin Date: Sat, 17 Jan 2015 14:31:30 +0000 Subject: [PATCH] Support for building an hardened OpenWRT Introduce configuration options to build an "hardened" OpenWRT. Options to enable Stack-Smashing Protection, FORTIFY_SOURCE and RELRO have been introduced. uClibc makefile now automatically detects if SSP support is necessary. hostapd makefile has been fixed to use "^" as sed separator since using a comma was problematic when using "-Wl,-z,now" and the like in TARGET_CFLAGS. Currently enabling SSP on user space depends on enabling SSP kernel side, this is due to the fact that TARGET_CFLAGS are used to build kernel modules (at least). Suggestions on how to avoid this are welcome. Using "select" instead of "depends on" doesn't seem to work with choice entries. Tested with a lantiq (WBMR) router, GCC 4.8, uClibc and a subset of the available packages. Needs to be tested with GCC 4.9 and the remaining packages. PIE not currently included. Signed-off-by: Alessandro Di Federico SVN-Revision: 44005 --- config/Config-build.in | 88 ++++++++++++++++++++--- include/package.mk | 36 ++++++++++ package/network/services/hostapd/Makefile | 2 +- toolchain/uClibc/common.mk | 1 + 4 files changed, 117 insertions(+), 10 deletions(-) diff --git a/config/Config-build.in b/config/Config-build.in index 89cf964a8e..280f71923b 100644 --- a/config/Config-build.in +++ b/config/Config-build.in @@ -97,15 +97,6 @@ menu "Global build settings" If you are unsure, select N. - config PKG_CHECK_FORMAT_SECURITY - bool - prompt "Enable gcc format-security" - default n - help - Add -Wformat -Werror=format-security to the CFLAGS. You can disable - this per package by adding PKG_CHECK_FORMAT_SECURITY:=0 in the package - Makefile. - config PKG_BUILD_USE_JOBSERVER bool prompt "Use top-level make jobserver for packages" @@ -216,4 +207,83 @@ menu "Global build settings" bool "libstdc++" endchoice + comment "Hardening build options" + + config PKG_CHECK_FORMAT_SECURITY + bool + prompt "Enable gcc format-security" + default n + help + Add -Wformat -Werror=format-security to the CFLAGS. You can disable + this per package by adding PKG_CHECK_FORMAT_SECURITY:=0 in the package + Makefile. + + choice + prompt "User space Stack-Smashing Protection" + default PKG_CC_STACKPROTECTOR_NONE + help + Enable GCC Stack Smashing Protection (SSP) for userspace applications + config PKG_CC_STACKPROTECTOR_NONE + bool "None" + config PKG_CC_STACKPROTECTOR_REGULAR + bool "Regular" + select SSP_SUPPORT + depends on KERNEL_CC_STACKPROTECTOR_REGULAR + config PKG_CC_STACKPROTECTOR_STRONG + bool "Strong" + select SSP_SUPPORT + depends on GCC_VERSION_4_9_LINARO + depends on KERNEL_CC_STACKPROTECTOR_STRONG + endchoice + + choice + prompt "Kernel space Stack-Smashing Protection" + default KERNEL_CC_STACKPROTECTOR_NONE + help + Enable GCC Stack-Smashing Protection (SSP) for the kernel + config KERNEL_CC_STACKPROTECTOR_NONE + bool "None" + config KERNEL_CC_STACKPROTECTOR_REGULAR + bool "Regular" + config KERNEL_CC_STACKPROTECTOR_STRONG + depends on GCC_VERSION_4_9_LINARO + bool "Strong" + endchoice + + choice + prompt "Enable buffer-overflows detction (FORTIFY_SOURCE)" + help + Enable the _FORTIFY_SOURCE macro which introduces additional + checks to detect buffer-overflows in the following standard library + functions: memcpy, mempcpy, memmove, memset, strcpy, stpcpy, + strncpy, strcat, strncat, sprintf, vsprintf, snprintf, vsnprintf, + gets. "Conservative" (_FORTIFY_SOURCE set to 1) only introduces + checks that sholdn't change the behavior of conforming programs, + while "aggressive" (_FORTIFY_SOURCES set to 2) some more checking is + added, but some conforming programs might fail. + config PKG_FORTIFY_SOURCE_NONE + bool "None" + config PKG_FORTIFY_SOURCE_1 + bool "Conservative" + config PKG_FORTIFY_SOURCE_2 + bool "Aggressive" + endchoice + + choice + prompt "Enable RELRO protection" + help + Enable a link-time protection know as RELRO (Relocation Read Only) + which helps to protect from certain type of exploitation techniques + altering the content of some ELF sections. "Partial" RELRO makes the + .dynamic section not writeable after initialization, introducing + almost no performance penalty, while "full" RELRO also marks the GOT + as read-only at the cost of initializing all of it at startup. + config PKG_RELRO_NONE + bool "None" + config PKG_RELRO_PARTIAL + bool "Partial" + config PKG_RELRO_FULL + bool "Full" + endchoice + endmenu diff --git a/include/package.mk b/include/package.mk index a1b90da38a..2c34a5850c 100644 --- a/include/package.mk +++ b/include/package.mk @@ -15,6 +15,12 @@ PKG_MD5SUM ?= unknown PKG_BUILD_PARALLEL ?= PKG_USE_MIPS16 ?= 1 PKG_CHECK_FORMAT_SECURITY ?= 1 +PKG_CC_STACKPROTECTOR_REGULAR ?= 1 +PKG_CC_STACKPROTECTOR_STRONG ?= 1 +PKG_FORTIFY_SOURCE_1 ?= 1 +PKG_FORTIFY_SOURCE_2 ?= 1 +PKG_RELRO_PARTIAL ?= 1 +PKG_RELRO_FULL ?= 1 ifneq ($(CONFIG_PKG_BUILD_USE_JOBSERVER),) MAKE_J:=$(if $(MAKE_JOBSERVER),$(MAKE_JOBSERVER) -j) @@ -39,6 +45,36 @@ ifdef CONFIG_PKG_CHECK_FORMAT_SECURITY TARGET_CFLAGS += -Wformat -Werror=format-security endif endif +ifdef CONFIG_PKG_CC_STACKPROTECTOR_REGULAR + ifeq ($(strip $(PKG_CC_STACKPROTECTOR_REGULAR)),1) + TARGET_CFLAGS += -fstack-protector + endif +endif +ifdef CONFIG_PKG_CC_STACKPROTECTOR_STRONG + ifeq ($(strip $(PKG_CC_STACKPROTECTOR_STRONG)),1) + TARGET_CFLAGS += -fstack-protector-strong + endif +endif +ifdef CONFIG_PKG_FORTIFY_SOURCE_1 + ifeq ($(strip $(PKG_FORTIFY_SOURCE_1)),1) + TARGET_CFLAGS += -D_FORTIFY_SOURCE=1 + endif +endif +ifdef CONFIG_PKG_FORTIFY_SOURCE_2 + ifeq ($(strip $(PKG_FORTIFY_SOURCE_2)),1) + TARGET_CFLAGS += -D_FORTIFY_SOURCE=2 + endif +endif +ifdef CONFIG_PKG_RELRO_PARTIAL + ifeq ($(strip $(PKG_RELRO_PARTIAL)),1) + TARGET_CFLAGS += -Wl,-z,relro + endif +endif +ifdef CONFIG_PKG_RELRO_FULL + ifeq ($(strip $(PKG_RELRO_FULL)),1) + TARGET_CFLAGS += -Wl,-z,now -Wl,-z,relro + endif +endif include $(INCLUDE_DIR)/prereq.mk include $(INCLUDE_DIR)/host.mk diff --git a/package/network/services/hostapd/Makefile b/package/network/services/hostapd/Makefile index 19d536ecc0..6bdf5341e0 100644 --- a/package/network/services/hostapd/Makefile +++ b/package/network/services/hostapd/Makefile @@ -294,7 +294,7 @@ define Build/Compile/wpad echo ` \ $(call Build/RunMake,hostapd,-s MULTICALL=1 dump_cflags); \ $(call Build/RunMake,wpa_supplicant,-s MULTICALL=1 dump_cflags) | \ - sed -e 's,-n ,,g' -e 's,$(TARGET_CFLAGS),,' \ + sed -e 's,-n ,,g' -e 's^$(TARGET_CFLAGS)^^' \ ` > $(PKG_BUILD_DIR)/.cflags +$(call Build/RunMake,hostapd, \ CFLAGS="$$$$(cat $(PKG_BUILD_DIR)/.cflags)" \ diff --git a/toolchain/uClibc/common.mk b/toolchain/uClibc/common.mk index e507dc6fb0..435e4c2511 100644 --- a/toolchain/uClibc/common.mk +++ b/toolchain/uClibc/common.mk @@ -80,6 +80,7 @@ define Host/Configure -e 's,^.*UCLIBC_HAS_SHADOW.*,UCLIBC_HAS_SHADOW=$(if $(CONFIG_SHADOW_PASSWORDS),y,n),g' \ -e 's,^.*UCLIBC_HAS_LOCALE.*,UCLIBC_HAS_LOCALE=$(if $(CONFIG_BUILD_NLS),y,n),g' \ -e 's,^.*UCLIBC_BUILD_ALL_LOCALE.*,UCLIBC_BUILD_ALL_LOCALE=$(if $(CONFIG_BUILD_NLS),y,n),g' \ + -e 's,^.*UCLIBC_HAS_SSP.*,UCLIBC_HAS_SSP=$(if $(or $(CONFIG_PKG_CC_STACKPROTECTOR_REGULAR),$(CONFIG_PKG_CC_STACKPROTECTOR_STRONG)),y,n),g' \ $(HOST_BUILD_DIR)/.config.new cmp -s $(HOST_BUILD_DIR)/.config.new $(HOST_BUILD_DIR)/.config.last || { \ cp $(HOST_BUILD_DIR)/.config.new $(HOST_BUILD_DIR)/.config && \ -- 2.30.2