stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures
Instead of duplicating the CC_STACKPROTECTOR Kconfig and
Makefile logic in each architecture, switch to using
HAVE_CC_STACKPROTECTOR and keep everything in one place. This
retains the x86-specific bug verification scripts.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@linux-mips.org
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1387481759-14535-2-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/Makefile b/Makefile
index 858a147..84fb5cd 100644
--- a/Makefile
+++ b/Makefile
@@ -595,10 +595,18 @@
KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
endif
-# Force gcc to behave correct even for buggy distributions
-ifndef CONFIG_CC_STACKPROTECTOR
-KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
+# Handle stack protector mode.
+ifdef CONFIG_CC_STACKPROTECTOR
+ stackp-flag := -fstack-protector
+ ifeq ($(call cc-option, $(stackp-flag)),)
+ $(warning Cannot use CONFIG_CC_STACKPROTECTOR: \
+ -fstack-protector not supported by compiler))
+ endif
+else
+ # Force off for distro compilers that enable stack protector by default.
+ stackp-flag := $(call cc-option, -fno-stack-protector)
endif
+KBUILD_CFLAGS += $(stackp-flag)
# This warning generated too much noise in a regular build.
# Use make W=1 to enable this warning (see scripts/Makefile.build)
diff --git a/arch/Kconfig b/arch/Kconfig
index f1cf895..24e026d 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -336,6 +336,28 @@
See Documentation/prctl/seccomp_filter.txt for details.
+config HAVE_CC_STACKPROTECTOR
+ bool
+ help
+ An arch should select this symbol if:
+ - its compiler supports the -fstack-protector option
+ - it has implemented a stack canary (e.g. __stack_chk_guard)
+
+config CC_STACKPROTECTOR
+ bool "Enable -fstack-protector buffer overflow detection"
+ depends on HAVE_CC_STACKPROTECTOR
+ help
+ This option turns on the -fstack-protector GCC feature. This
+ feature puts, at the beginning of functions, a canary value on
+ the stack just before the return address, and validates
+ the value just before actually returning. Stack based buffer
+ overflows (that need to overwrite this return address) now also
+ overwrite the canary, which gets detected and the attack is then
+ neutralized via a kernel panic.
+
+ This feature requires gcc version 4.2 or above, or a distribution
+ gcc with the feature backported.
+
config HAVE_CONTEXT_TRACKING
bool
help
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c1f1a7e..9c909fc 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -30,6 +30,7 @@
select HAVE_BPF_JIT
select HAVE_CONTEXT_TRACKING
select HAVE_C_RECORDMCOUNT
+ select HAVE_CC_STACKPROTECTOR
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_API_DEBUG
select HAVE_DMA_ATTRS
@@ -1856,18 +1857,6 @@
and the task is only allowed to execute a few safe syscalls
defined by each seccomp mode.
-config CC_STACKPROTECTOR
- bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
- help
- This option turns on the -fstack-protector GCC feature. This
- feature puts, at the beginning of functions, a canary value on
- the stack just before the return address, and validates
- the value just before actually returning. Stack based buffer
- overflows (that need to overwrite this return address) now also
- overwrite the canary, which gets detected and the attack is then
- neutralized via a kernel panic.
- This feature requires gcc version 4.2 or above.
-
config SWIOTLB
def_bool y
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index c99b108..55b4255 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -40,10 +40,6 @@
KBUILD_CFLAGS +=-fno-omit-frame-pointer -mapcs -mno-sched-prolog
endif
-ifeq ($(CONFIG_CC_STACKPROTECTOR),y)
-KBUILD_CFLAGS +=-fstack-protector
-endif
-
ifeq ($(CONFIG_CPU_BIG_ENDIAN),y)
KBUILD_CPPFLAGS += -mbig-endian
AS += -EB
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 650de39..c93d92b 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -47,6 +47,7 @@
select MODULES_USE_ELF_RELA if MODULES && 64BIT
select CLONE_BACKWARDS
select HAVE_DEBUG_STACKOVERFLOW
+ select HAVE_CC_STACKPROTECTOR
menu "Machine selection"
@@ -2322,19 +2323,6 @@
If unsure, say Y. Only embedded should say N here.
-config CC_STACKPROTECTOR
- bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
- help
- This option turns on the -fstack-protector GCC feature. This
- feature puts, at the beginning of functions, a canary value on
- the stack just before the return address, and validates
- the value just before actually returning. Stack based buffer
- overflows (that need to overwrite this return address) now also
- overwrite the canary, which gets detected and the attack is then
- neutralized via a kernel panic.
-
- This feature requires gcc version 4.2 or above.
-
config USE_OF
bool
select OF
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index de300b9..efe50787 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -232,10 +232,6 @@
LDFLAGS += -m $(ld-emul)
-ifdef CONFIG_CC_STACKPROTECTOR
- KBUILD_CFLAGS += -fstack-protector
-endif
-
ifdef CONFIG_MIPS
CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \
egrep -vw '__GNUC_(|MINOR_|PATCHLEVEL_)_' | \
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 9b0979f..ce29831 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -66,6 +66,7 @@
select PERF_EVENTS
select ARCH_HIBERNATION_POSSIBLE if MMU
select SPARSE_IRQ
+ select HAVE_CC_STACKPROTECTOR
config SUPERH64
def_bool ARCH = "sh64"
@@ -695,20 +696,6 @@
If unsure, say N.
-config CC_STACKPROTECTOR
- bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
- depends on SUPERH32
- help
- This option turns on the -fstack-protector GCC feature. This
- feature puts, at the beginning of functions, a canary value on
- the stack just before the return address, and validates
- the value just before actually returning. Stack based buffer
- overflows (that need to overwrite this return address) now also
- overwrite the canary, which gets detected and the attack is then
- neutralized via a kernel panic.
-
- This feature requires gcc version 4.2 or above.
-
config SMP
bool "Symmetric multi-processing support"
depends on SYS_SUPPORTS_SMP
diff --git a/arch/sh/Makefile b/arch/sh/Makefile
index aed701c..d4d16e4 100644
--- a/arch/sh/Makefile
+++ b/arch/sh/Makefile
@@ -199,10 +199,6 @@
KBUILD_CFLAGS += -fasynchronous-unwind-tables
endif
-ifeq ($(CONFIG_CC_STACKPROTECTOR),y)
- KBUILD_CFLAGS += -fstack-protector
-endif
-
libs-$(CONFIG_SUPERH32) := arch/sh/lib/ $(libs-y)
libs-$(CONFIG_SUPERH64) := arch/sh/lib64/ $(libs-y)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 0952ecd..838e7c3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -125,6 +125,7 @@
select RTC_LIB
select HAVE_DEBUG_STACKOVERFLOW
select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
+ select HAVE_CC_STACKPROTECTOR
config INSTRUCTION_DECODER
def_bool y
@@ -1617,22 +1618,6 @@
If unsure, say Y. Only embedded should say N here.
-config CC_STACKPROTECTOR
- bool "Enable -fstack-protector buffer overflow detection"
- ---help---
- This option turns on the -fstack-protector GCC feature. This
- feature puts, at the beginning of functions, a canary value on
- the stack just before the return address, and validates
- the value just before actually returning. Stack based buffer
- overflows (that need to overwrite this return address) now also
- overwrite the canary, which gets detected and the attack is then
- neutralized via a kernel panic.
-
- This feature requires gcc version 4.2 or above, or a distribution
- gcc with the feature backported. Older versions are automatically
- detected and for those versions, this configuration option is
- ignored. (and a warning is printed during bootup)
-
source kernel/Kconfig.hz
config KEXEC
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 57d0215..13b22e0 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -89,13 +89,11 @@
KBUILD_CFLAGS += -maccumulate-outgoing-args
endif
+# Make sure compiler does not have buggy stack-protector support.
ifdef CONFIG_CC_STACKPROTECTOR
cc_has_sp := $(srctree)/scripts/gcc-x86_$(BITS)-has-stack-protector.sh
- ifeq ($(shell $(CONFIG_SHELL) $(cc_has_sp) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y)
- stackp-y := -fstack-protector
- KBUILD_CFLAGS += $(stackp-y)
- else
- $(warning stack protector enabled but no compiler support)
+ ifneq ($(shell $(CONFIG_SHELL) $(cc_has_sp) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y)
+ $(warning stack-protector enabled but compiler support broken)
endif
endif
