diff options
| -rw-r--r-- | Makefile | 20 | ||||
| -rw-r--r-- | arch/Kconfig | 67 | ||||
| -rw-r--r-- | arch/arm/Kconfig | 13 | ||||
| -rw-r--r-- | arch/arm/Makefile | 4 | ||||
| -rw-r--r-- | arch/arm/boot/compressed/misc.c | 14 | ||||
| -rw-r--r-- | arch/mips/Kconfig | 14 | ||||
| -rw-r--r-- | arch/mips/Makefile | 4 | ||||
| -rw-r--r-- | arch/sh/Kconfig | 15 | ||||
| -rw-r--r-- | arch/sh/Makefile | 4 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 17 | ||||
| -rw-r--r-- | arch/x86/Makefile | 8 |
11 files changed, 105 insertions, 75 deletions
@@ -595,10 +595,24 @@ 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 += $(call cc-option, -fno-stack-protector) +# Handle stack protector mode. +ifdef CONFIG_CC_STACKPROTECTOR_REGULAR + stackp-flag := -fstack-protector + ifeq ($(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) 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..80bbb8c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -336,6 +336,73 @@ 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 + 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 "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 + 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. + +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 ("-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 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 @@ 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 @@ -1856,18 +1857,6 @@ 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 c99b108..55b4255 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/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; 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 0952ecd..838e7c3 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -125,6 +125,7 @@ config X86 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 @@ 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 |
