summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--config/Config-build.in16
-rw-r--r--include/hardened-ld-pie.specs2
-rw-r--r--include/hardening.mk7
-rw-r--r--package/utils/busybox/Makefile3
4 files changed, 28 insertions, 0 deletions
diff --git a/config/Config-build.in b/config/Config-build.in
index 7ec7653..660da1c 100644
--- a/config/Config-build.in
+++ b/config/Config-build.in
@@ -184,6 +184,22 @@ menu "Global build settings"
this per package by adding PKG_CHECK_FORMAT_SECURITY:=0 in the package
Makefile.
+ config PKG_ASLR_PIE
+ bool
+ prompt "User space ASLR PIE compilation"
+ select BUSYBOX_DEFAULT_PIE
+ default n
+ help
+ Add -fPIC to CFLAGS and -specs=hardened-build-ld to LDFLAGS.
+ This enables package build as Position Independent Executables (PIE)
+ to protect against "return-to-text" attacks. This belongs to the
+ feature of Address Space Layout Randomisation (ASLR), which is
+ implemented by the kernel and the ELF loader by randomising the
+ location of memory allocations. This makes memory addresses harder
+ 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.
+
choice
prompt "User space Stack-Smashing Protection"
depends on USE_MUSL
diff --git a/include/hardened-ld-pie.specs b/include/hardened-ld-pie.specs
new file mode 100644
index 0000000..7317b19
--- /dev/null
+++ b/include/hardened-ld-pie.specs
@@ -0,0 +1,2 @@
+*self_spec:
++ %{no-pie|static|r|shared:;:-pie}
diff --git a/include/hardening.mk b/include/hardening.mk
index c277081..06a6178 100644
--- a/include/hardening.mk
+++ b/include/hardening.mk
@@ -6,6 +6,7 @@
#
PKG_CHECK_FORMAT_SECURITY ?= 1
+PKG_ASLR_PIE ?= 1
PKG_SSP ?= 1
PKG_FORTIFY_SOURCE ?= 1
PKG_RELRO ?= 1
@@ -15,6 +16,12 @@ ifdef CONFIG_PKG_CHECK_FORMAT_SECURITY
TARGET_CFLAGS += -Wformat -Werror=format-security
endif
endif
+ifdef CONFIG_PKG_ASLR_PIE
+ ifeq ($(strip $(PKG_ASLR_PIE)),1)
+ TARGET_CFLAGS += -fPIC
+ TARGET_LDFLAGS += -specs=$(INCLUDE_DIR)/hardened-ld-pie.specs
+ endif
+endif
ifdef CONFIG_PKG_CC_STACKPROTECTOR_REGULAR
ifeq ($(strip $(PKG_SSP)),1)
TARGET_CFLAGS += -fstack-protector
diff --git a/package/utils/busybox/Makefile b/package/utils/busybox/Makefile
index 8866756..4f85cc9 100644
--- a/package/utils/busybox/Makefile
+++ b/package/utils/busybox/Makefile
@@ -22,6 +22,9 @@ PKG_BUILD_PARALLEL:=1
PKG_CHECK_FORMAT_SECURITY:=0
PKG_INSTALL:=1
+#Busybox use it's own PIE config flag and LDFLAGS are used with ld, not gcc.
+PKG_ASLR_PIE:=0
+
PKG_LICENSE:=GPL-2.0
PKG_LICENSE_FILES:=LICENSE archival/libarchive/bz/LICENSE
PKG_CPE_ID:=cpe:/a:busybox:busybox