* [PATCH 3.13.y-ckt 02/78] stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures [not found] <1450312802-4938-1-git-send-email-kamal@canonical.com> @ 2015-12-17 0:38 ` Kamal Mostafa 2015-12-17 0:38 ` Kamal Mostafa 2015-12-17 0:38 ` [PATCH 3.13.y-ckt 03/78] stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG Kamal Mostafa 1 sibling, 1 reply; 4+ messages in thread From: Kamal Mostafa @ 2015-12-17 0:38 UTC (permalink / raw) To: linux-kernel, stable, kernel-team Cc: Michal Marek, Stephen Rothwell, James Hogan, Russell King, Kees Cook, linux-mips, Peter Zijlstra, Linus Torvalds, Kamal Mostafa, Ralf Baechle, Ingo Molnar, Paul Mundt, linux-arch, Andrew Morton, Shawn Guo, Arjan van de Ven, Thomas Gleixner, linux-arm-kernel 3.13.11-ckt32 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook <keescook@chromium.org> commit 19952a92037e752f9d3bbbad552d596f9a56e146 upstream. 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> [ kamal: 3.13-stable prereq for 8779657 stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- Makefile | 14 +++++++++++--- arch/Kconfig | 22 ++++++++++++++++++++++ arch/arm/Kconfig | 13 +------------ arch/arm/Makefile | 4 ---- arch/mips/Kconfig | 14 +------------- arch/mips/Makefile | 4 ---- arch/sh/Kconfig | 15 +-------------- arch/sh/Makefile | 4 ---- arch/x86/Kconfig | 17 +---------------- arch/x86/Makefile | 8 +++----- 10 files changed, 40 insertions(+), 75 deletions(-) diff --git a/Makefile b/Makefile index 7606094..58a799e 100644 --- a/Makefile +++ b/Makefile @@ -597,10 +597,18 @@ ifneq ($(CONFIG_FRAME_WARN),0) 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 @@ config SECCOMP_FILTER 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 b3d400d..5102fd5 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -31,6 +31,7 @@ config ARM 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 @@ -1859,18 +1860,6 @@ config SECCOMP 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 749e88f..bc050dc 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -40,10 +40,6 @@ ifeq ($(CONFIG_FRAME_POINTER),y) 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 @@ config MIPS 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 @@ config SECCOMP 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 @@ bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y) \ LDFLAGS += -m $(ld-emul) -ifdef CONFIG_CC_STACKPROTECTOR - KBUILD_CFLAGS += -fstack-protector -endif - ifdef CONFIG_MIPS CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \ egrep -vw '__GNUC_(|MINOR_|PATCHLEVEL_)_' | \ diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 9b0979f..ce29831 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -66,6 +66,7 @@ config SUPERH32 select PERF_EVENTS select ARCH_HIBERNATION_POSSIBLE if MMU select SPARSE_IRQ + select HAVE_CC_STACKPROTECTOR config SUPERH64 def_bool ARCH = "sh64" @@ -695,20 +696,6 @@ config SECCOMP If unsure, say N. -config CC_STACKPROTECTOR - bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)" - depends on SUPERH32 - help - This option turns on the -fstack-protector GCC feature. This - feature puts, at the beginning of functions, a canary value on - the stack just before the return address, and validates - the value just before actually returning. Stack based buffer - overflows (that need to overwrite this return address) now also - overwrite the canary, which gets detected and the attack is then - neutralized via a kernel panic. - - This feature requires gcc version 4.2 or above. - config SMP bool "Symmetric multi-processing support" depends on SYS_SUPPORTS_SMP diff --git a/arch/sh/Makefile b/arch/sh/Makefile index aed701c..d4d16e4 100644 --- a/arch/sh/Makefile +++ b/arch/sh/Makefile @@ -199,10 +199,6 @@ ifeq ($(CONFIG_DWARF_UNWINDER),y) 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 223080d..250706e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -126,6 +126,7 @@ config X86 select HAVE_DEBUG_STACKOVERFLOW select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 select ARCH_SUPPORTS_ATOMIC_RMW + select HAVE_CC_STACKPROTECTOR config INSTRUCTION_DECODER def_bool y @@ -1640,22 +1641,6 @@ config SECCOMP 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 @@ else 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 -- 1.9.1 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 3.13.y-ckt 02/78] stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures 2015-12-17 0:38 ` [PATCH 3.13.y-ckt 02/78] stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures Kamal Mostafa @ 2015-12-17 0:38 ` Kamal Mostafa 0 siblings, 0 replies; 4+ messages in thread From: Kamal Mostafa @ 2015-12-17 0:38 UTC (permalink / raw) To: linux-kernel, stable, kernel-team Cc: Kees Cook, Arjan van de Ven, Michal Marek, Russell King, Ralf Baechle, Paul Mundt, James Hogan, Stephen Rothwell, Shawn Guo, Linus Torvalds, Andrew Morton, Peter Zijlstra, Thomas Gleixner, linux-arm-kernel, linux-mips, linux-arch, Ingo Molnar, Kamal Mostafa 3.13.11-ckt32 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook <keescook@chromium.org> commit 19952a92037e752f9d3bbbad552d596f9a56e146 upstream. 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> [ kamal: 3.13-stable prereq for 8779657 stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- Makefile | 14 +++++++++++--- arch/Kconfig | 22 ++++++++++++++++++++++ arch/arm/Kconfig | 13 +------------ arch/arm/Makefile | 4 ---- arch/mips/Kconfig | 14 +------------- arch/mips/Makefile | 4 ---- arch/sh/Kconfig | 15 +-------------- arch/sh/Makefile | 4 ---- arch/x86/Kconfig | 17 +---------------- arch/x86/Makefile | 8 +++----- 10 files changed, 40 insertions(+), 75 deletions(-) diff --git a/Makefile b/Makefile index 7606094..58a799e 100644 --- a/Makefile +++ b/Makefile @@ -597,10 +597,18 @@ ifneq ($(CONFIG_FRAME_WARN),0) 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 @@ config SECCOMP_FILTER 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 b3d400d..5102fd5 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -31,6 +31,7 @@ config ARM 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 @@ -1859,18 +1860,6 @@ config SECCOMP 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 749e88f..bc050dc 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -40,10 +40,6 @@ ifeq ($(CONFIG_FRAME_POINTER),y) 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 @@ config MIPS 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 @@ config SECCOMP 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 @@ bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y) \ LDFLAGS += -m $(ld-emul) -ifdef CONFIG_CC_STACKPROTECTOR - KBUILD_CFLAGS += -fstack-protector -endif - ifdef CONFIG_MIPS CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \ egrep -vw '__GNUC_(|MINOR_|PATCHLEVEL_)_' | \ diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 9b0979f..ce29831 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -66,6 +66,7 @@ config SUPERH32 select PERF_EVENTS select ARCH_HIBERNATION_POSSIBLE if MMU select SPARSE_IRQ + select HAVE_CC_STACKPROTECTOR config SUPERH64 def_bool ARCH = "sh64" @@ -695,20 +696,6 @@ config SECCOMP If unsure, say N. -config CC_STACKPROTECTOR - bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)" - depends on SUPERH32 - help - This option turns on the -fstack-protector GCC feature. This - feature puts, at the beginning of functions, a canary value on - the stack just before the return address, and validates - the value just before actually returning. Stack based buffer - overflows (that need to overwrite this return address) now also - overwrite the canary, which gets detected and the attack is then - neutralized via a kernel panic. - - This feature requires gcc version 4.2 or above. - config SMP bool "Symmetric multi-processing support" depends on SYS_SUPPORTS_SMP diff --git a/arch/sh/Makefile b/arch/sh/Makefile index aed701c..d4d16e4 100644 --- a/arch/sh/Makefile +++ b/arch/sh/Makefile @@ -199,10 +199,6 @@ ifeq ($(CONFIG_DWARF_UNWINDER),y) 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 223080d..250706e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -126,6 +126,7 @@ config X86 select HAVE_DEBUG_STACKOVERFLOW select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 select ARCH_SUPPORTS_ATOMIC_RMW + select HAVE_CC_STACKPROTECTOR config INSTRUCTION_DECODER def_bool y @@ -1640,22 +1641,6 @@ config SECCOMP 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 @@ else 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 -- 1.9.1 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 3.13.y-ckt 03/78] stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG [not found] <1450312802-4938-1-git-send-email-kamal@canonical.com> 2015-12-17 0:38 ` [PATCH 3.13.y-ckt 02/78] stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures Kamal Mostafa @ 2015-12-17 0:38 ` Kamal Mostafa 2015-12-17 0:38 ` Kamal Mostafa 1 sibling, 1 reply; 4+ messages in thread From: Kamal Mostafa @ 2015-12-17 0:38 UTC (permalink / raw) To: linux-kernel, stable, kernel-team Cc: Michal Marek, Stephen Rothwell, James Hogan, Russell King, Kees Cook, linux-mips, Peter Zijlstra, Linus Torvalds, Kamal Mostafa, Ralf Baechle, Paul Mundt, linux-arch, Andrew Morton, Shawn Guo, Arjan van de Ven, Ingo Molnar, linux-arm-kernel 3.13.11-ckt32 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook <keescook@chromium.org> commit 8779657d29c0ebcc0c94ede4df2f497baf1b563f upstream. This changes the stack protector config option into a choice of "None", "Regular", and "Strong": CONFIG_CC_STACKPROTECTOR_NONE CONFIG_CC_STACKPROTECTOR_REGULAR CONFIG_CC_STACKPROTECTOR_STRONG "Regular" means the old CONFIG_CC_STACKPROTECTOR=y option. "Strong" is a new mode introduced by this patch. With "Strong" the kernel is built with -fstack-protector-strong (available in gcc 4.9 and later). This option increases the coverage of the stack protector without the heavy performance hit of -fstack-protector-all. For reference, the stack protector options available in gcc are: -fstack-protector-all: Adds the stack-canary saving prefix and stack-canary checking suffix to _all_ function entry and exit. Results in substantial use of stack space for saving the canary for deep stack users (e.g. historically xfs), and measurable (though shockingly still low) performance hit due to all the saving/checking. Really not suitable for sane systems, and was entirely removed as an option from the kernel many years ago. -fstack-protector: Adds the canary save/check to functions that define an 8 (--param=ssp-buffer-size=N, N=8 by default) or more byte local char array. Traditionally, stack overflows happened with string-based manipulations, so this was a way to find those functions. Very few total functions actually get the canary; no measurable performance or size overhead. -fstack-protector-strong Adds the canary for a wider set of functions, since it's not just those with strings that have ultimately been vulnerable to stack-busting. With this superset, more functions end up with a canary, but it still remains small compared to all functions with only a small change in performance. Based on the original design document, a function gets the canary when it contains any of: - local variable's address used as part of the right hand side of an assignment or function argument - local variable is an array (or union containing an array), regardless of array type or length - uses register local variables https://docs.google.com/a/google.com/document/d/1xXBH6rRZue4f296vGt9YQcuLVQHeE516stHwt8M9xyU Find below a comparison of "size" and "objdump" output when built with gcc-4.9 in three configurations: - defconfig 11430641 kernel text size 36110 function bodies - defconfig + CONFIG_CC_STACKPROTECTOR_REGULAR 11468490 kernel text size (+0.33%) 1015 of 36110 functions are stack-protected (2.81%) - defconfig + CONFIG_CC_STACKPROTECTOR_STRONG via this patch 11692790 kernel text size (+2.24%) 7401 of 36110 functions are stack-protected (20.5%) With -strong, ARM's compressed boot code now triggers stack protection, so a static guard was added. Since this is only used during decompression and was never used before, the exposure here is very small. Once it switches to the full kernel, the stack guard is back to normal. Chrome OS has been using -fstack-protector-strong for its kernel builds for the last 8 months with no problems. 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: linux-arm-kernel@lists.infradead.org Cc: linux-mips@linux-mips.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1387481759-14535-3-git-send-email-keescook@chromium.org [ Improved the changelog and descriptions some more. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> [ kamal: 3.13-stable: need these arch/arm/boot/compressed/misc.c __stack_chk canary functions, even for just the old CONFIG_CC_STACKPROTECTOR ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- Makefile | 8 ++++++- arch/Kconfig | 51 ++++++++++++++++++++++++++++++++++++++--- arch/arm/boot/compressed/misc.c | 14 +++++++++++ 3 files changed, 69 insertions(+), 4 deletions(-) diff --git a/Makefile b/Makefile index 58a799e..b43786f 100644 --- a/Makefile +++ b/Makefile @@ -598,12 +598,18 @@ KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN}) endif # Handle stack protector mode. -ifdef CONFIG_CC_STACKPROTECTOR +ifdef CONFIG_CC_STACKPROTECTOR_REGULAR stackp-flag := -fstack-protector ifeq ($(call cc-option, $(stackp-flag)),) $(warning Cannot use CONFIG_CC_STACKPROTECTOR: \ -fstack-protector not supported by compiler)) endif +else ifdef CONFIG_CC_STACKPROTECTOR_STRONG + stackp-flag := -fstack-protector-strong + ifeq ($(call cc-option, $(stackp-flag)),) + $(warning Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: \ + -fstack-protector-strong 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) diff --git a/arch/Kconfig b/arch/Kconfig index 24e026d..80bbb8c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -344,10 +344,17 @@ config HAVE_CC_STACKPROTECTOR - it has implemented a stack canary (e.g. __stack_chk_guard) config CC_STACKPROTECTOR - bool "Enable -fstack-protector buffer overflow detection" + def_bool n + help + Set when a stack-protector mode is enabled, so that the build + can enable kernel-side support for the GCC feature. + +choice + prompt "Stack Protector buffer overflow detection" depends on HAVE_CC_STACKPROTECTOR + default CC_STACKPROTECTOR_NONE help - This option turns on the -fstack-protector GCC feature. This + This option turns on the "stack-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 @@ -355,8 +362,46 @@ config CC_STACKPROTECTOR overwrite the canary, which gets detected and the attack is then neutralized via a kernel panic. +config CC_STACKPROTECTOR_NONE + bool "None" + help + Disable "stack-protector" GCC feature. + +config CC_STACKPROTECTOR_REGULAR + bool "Regular" + select CC_STACKPROTECTOR + help + Functions will have the stack-protector canary logic added if they + have an 8-byte or larger character array on the stack. + This feature requires gcc version 4.2 or above, or a distribution - gcc with the feature backported. + gcc with the feature backported ("-fstack-protector"). + + On an x86 "defconfig" build, this feature adds canary checks to + about 3% of all kernel functions, which increases kernel code size + by about 0.3%. + +config CC_STACKPROTECTOR_STRONG + bool "Strong" + select CC_STACKPROTECTOR + help + Functions will have the stack-protector canary logic added in any + of the following conditions: + + - local variable's address used as part of the right hand side of an + assignment or function argument + - local variable is an array (or union containing an array), + regardless of array type or length + - uses register local variables + + This feature requires gcc version 4.9 or above, or a distribution + gcc with the feature backported ("-fstack-protector-strong"). + + On an x86 "defconfig" build, this feature adds canary checks to + about 20% of all kernel functions, which increases the kernel code + size by about 2%. + +endchoice config HAVE_CONTEXT_TRACKING bool diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c index 31bd43b..d4f891f 100644 --- a/arch/arm/boot/compressed/misc.c +++ b/arch/arm/boot/compressed/misc.c @@ -127,6 +127,18 @@ asmlinkage void __div0(void) error("Attempting division by 0!"); } +unsigned long __stack_chk_guard; + +void __stack_chk_guard_setup(void) +{ + __stack_chk_guard = 0x000a0dff; +} + +void __stack_chk_fail(void) +{ + error("stack-protector: Kernel stack is corrupted\n"); +} + extern int do_decompress(u8 *input, int len, u8 *output, void (*error)(char *x)); @@ -137,6 +149,8 @@ decompress_kernel(unsigned long output_start, unsigned long free_mem_ptr_p, { int ret; + __stack_chk_guard_setup(); + output_data = (unsigned char *)output_start; free_mem_ptr = free_mem_ptr_p; free_mem_end_ptr = free_mem_ptr_end_p; -- 1.9.1 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 3.13.y-ckt 03/78] stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG 2015-12-17 0:38 ` [PATCH 3.13.y-ckt 03/78] stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG Kamal Mostafa @ 2015-12-17 0:38 ` Kamal Mostafa 0 siblings, 0 replies; 4+ messages in thread From: Kamal Mostafa @ 2015-12-17 0:38 UTC (permalink / raw) To: linux-kernel, stable, kernel-team Cc: Kees Cook, Arjan van de Ven, Michal Marek, Russell King, Ralf Baechle, Paul Mundt, James Hogan, Stephen Rothwell, Shawn Guo, Linus Torvalds, Andrew Morton, Peter Zijlstra, linux-arm-kernel, linux-mips, linux-arch, Ingo Molnar, Kamal Mostafa 3.13.11-ckt32 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook <keescook@chromium.org> commit 8779657d29c0ebcc0c94ede4df2f497baf1b563f upstream. This changes the stack protector config option into a choice of "None", "Regular", and "Strong": CONFIG_CC_STACKPROTECTOR_NONE CONFIG_CC_STACKPROTECTOR_REGULAR CONFIG_CC_STACKPROTECTOR_STRONG "Regular" means the old CONFIG_CC_STACKPROTECTOR=y option. "Strong" is a new mode introduced by this patch. With "Strong" the kernel is built with -fstack-protector-strong (available in gcc 4.9 and later). This option increases the coverage of the stack protector without the heavy performance hit of -fstack-protector-all. For reference, the stack protector options available in gcc are: -fstack-protector-all: Adds the stack-canary saving prefix and stack-canary checking suffix to _all_ function entry and exit. Results in substantial use of stack space for saving the canary for deep stack users (e.g. historically xfs), and measurable (though shockingly still low) performance hit due to all the saving/checking. Really not suitable for sane systems, and was entirely removed as an option from the kernel many years ago. -fstack-protector: Adds the canary save/check to functions that define an 8 (--param=ssp-buffer-size=N, N=8 by default) or more byte local char array. Traditionally, stack overflows happened with string-based manipulations, so this was a way to find those functions. Very few total functions actually get the canary; no measurable performance or size overhead. -fstack-protector-strong Adds the canary for a wider set of functions, since it's not just those with strings that have ultimately been vulnerable to stack-busting. With this superset, more functions end up with a canary, but it still remains small compared to all functions with only a small change in performance. Based on the original design document, a function gets the canary when it contains any of: - local variable's address used as part of the right hand side of an assignment or function argument - local variable is an array (or union containing an array), regardless of array type or length - uses register local variables https://docs.google.com/a/google.com/document/d/1xXBH6rRZue4f296vGt9YQcuLVQHeE516stHwt8M9xyU Find below a comparison of "size" and "objdump" output when built with gcc-4.9 in three configurations: - defconfig 11430641 kernel text size 36110 function bodies - defconfig + CONFIG_CC_STACKPROTECTOR_REGULAR 11468490 kernel text size (+0.33%) 1015 of 36110 functions are stack-protected (2.81%) - defconfig + CONFIG_CC_STACKPROTECTOR_STRONG via this patch 11692790 kernel text size (+2.24%) 7401 of 36110 functions are stack-protected (20.5%) With -strong, ARM's compressed boot code now triggers stack protection, so a static guard was added. Since this is only used during decompression and was never used before, the exposure here is very small. Once it switches to the full kernel, the stack guard is back to normal. Chrome OS has been using -fstack-protector-strong for its kernel builds for the last 8 months with no problems. 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: linux-arm-kernel@lists.infradead.org Cc: linux-mips@linux-mips.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1387481759-14535-3-git-send-email-keescook@chromium.org [ Improved the changelog and descriptions some more. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> [ kamal: 3.13-stable: need these arch/arm/boot/compressed/misc.c __stack_chk canary functions, even for just the old CONFIG_CC_STACKPROTECTOR ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- Makefile | 8 ++++++- arch/Kconfig | 51 ++++++++++++++++++++++++++++++++++++++--- arch/arm/boot/compressed/misc.c | 14 +++++++++++ 3 files changed, 69 insertions(+), 4 deletions(-) diff --git a/Makefile b/Makefile index 58a799e..b43786f 100644 --- a/Makefile +++ b/Makefile @@ -598,12 +598,18 @@ KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN}) endif # Handle stack protector mode. -ifdef CONFIG_CC_STACKPROTECTOR +ifdef CONFIG_CC_STACKPROTECTOR_REGULAR stackp-flag := -fstack-protector ifeq ($(call cc-option, $(stackp-flag)),) $(warning Cannot use CONFIG_CC_STACKPROTECTOR: \ -fstack-protector not supported by compiler)) endif +else ifdef CONFIG_CC_STACKPROTECTOR_STRONG + stackp-flag := -fstack-protector-strong + ifeq ($(call cc-option, $(stackp-flag)),) + $(warning Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: \ + -fstack-protector-strong 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) diff --git a/arch/Kconfig b/arch/Kconfig index 24e026d..80bbb8c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -344,10 +344,17 @@ config HAVE_CC_STACKPROTECTOR - it has implemented a stack canary (e.g. __stack_chk_guard) config CC_STACKPROTECTOR - bool "Enable -fstack-protector buffer overflow detection" + def_bool n + help + Set when a stack-protector mode is enabled, so that the build + can enable kernel-side support for the GCC feature. + +choice + prompt "Stack Protector buffer overflow detection" depends on HAVE_CC_STACKPROTECTOR + default CC_STACKPROTECTOR_NONE help - This option turns on the -fstack-protector GCC feature. This + This option turns on the "stack-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 @@ -355,8 +362,46 @@ config CC_STACKPROTECTOR overwrite the canary, which gets detected and the attack is then neutralized via a kernel panic. +config CC_STACKPROTECTOR_NONE + bool "None" + help + Disable "stack-protector" GCC feature. + +config CC_STACKPROTECTOR_REGULAR + bool "Regular" + select CC_STACKPROTECTOR + help + Functions will have the stack-protector canary logic added if they + have an 8-byte or larger character array on the stack. + This feature requires gcc version 4.2 or above, or a distribution - gcc with the feature backported. + gcc with the feature backported ("-fstack-protector"). + + On an x86 "defconfig" build, this feature adds canary checks to + about 3% of all kernel functions, which increases kernel code size + by about 0.3%. + +config CC_STACKPROTECTOR_STRONG + bool "Strong" + select CC_STACKPROTECTOR + help + Functions will have the stack-protector canary logic added in any + of the following conditions: + + - local variable's address used as part of the right hand side of an + assignment or function argument + - local variable is an array (or union containing an array), + regardless of array type or length + - uses register local variables + + This feature requires gcc version 4.9 or above, or a distribution + gcc with the feature backported ("-fstack-protector-strong"). + + On an x86 "defconfig" build, this feature adds canary checks to + about 20% of all kernel functions, which increases the kernel code + size by about 2%. + +endchoice config HAVE_CONTEXT_TRACKING bool diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c index 31bd43b..d4f891f 100644 --- a/arch/arm/boot/compressed/misc.c +++ b/arch/arm/boot/compressed/misc.c @@ -127,6 +127,18 @@ asmlinkage void __div0(void) error("Attempting division by 0!"); } +unsigned long __stack_chk_guard; + +void __stack_chk_guard_setup(void) +{ + __stack_chk_guard = 0x000a0dff; +} + +void __stack_chk_fail(void) +{ + error("stack-protector: Kernel stack is corrupted\n"); +} + extern int do_decompress(u8 *input, int len, u8 *output, void (*error)(char *x)); @@ -137,6 +149,8 @@ decompress_kernel(unsigned long output_start, unsigned long free_mem_ptr_p, { int ret; + __stack_chk_guard_setup(); + output_data = (unsigned char *)output_start; free_mem_ptr = free_mem_ptr_p; free_mem_end_ptr = free_mem_ptr_end_p; -- 1.9.1 ^ permalink raw reply related [flat|nested] 4+ messages in thread
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2015-12-17 0:38 ` [PATCH 3.13.y-ckt 02/78] stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures Kamal Mostafa
2015-12-17 0:38 ` Kamal Mostafa
2015-12-17 0:38 ` [PATCH 3.13.y-ckt 03/78] stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG Kamal Mostafa
2015-12-17 0:38 ` Kamal Mostafa
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