From 050e9baa9dc9fbd9ce2b27f0056990fc9e0a08a0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 14 Jun 2018 12:21:18 +0900 Subject: Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables The changes to automatically test for working stack protector compiler support in the Kconfig files removed the special STACKPROTECTOR_AUTO option that picked the strongest stack protector that the compiler supported. That was all a nice cleanup - it makes no sense to have the AUTO case now that the Kconfig phase can just determine the compiler support directly. HOWEVER. It also meant that doing "make oldconfig" would now _disable_ the strong stackprotector if you had AUTO enabled, because in a legacy config file, the sane stack protector configuration would look like CONFIG_HAVE_CC_STACKPROTECTOR=y # CONFIG_CC_STACKPROTECTOR_NONE is not set # CONFIG_CC_STACKPROTECTOR_REGULAR is not set # CONFIG_CC_STACKPROTECTOR_STRONG is not set CONFIG_CC_STACKPROTECTOR_AUTO=y and when you ran this through "make oldconfig" with the Kbuild changes, it would ask you about the regular CONFIG_CC_STACKPROTECTOR (that had been renamed from CONFIG_CC_STACKPROTECTOR_REGULAR to just CONFIG_CC_STACKPROTECTOR), but it would think that the STRONG version used to be disabled (because it was really enabled by AUTO), and would disable it in the new config, resulting in: CONFIG_HAVE_CC_STACKPROTECTOR=y CONFIG_CC_HAS_STACKPROTECTOR_NONE=y CONFIG_CC_STACKPROTECTOR=y # CONFIG_CC_STACKPROTECTOR_STRONG is not set CONFIG_CC_HAS_SANE_STACKPROTECTOR=y That's dangerously subtle - people could suddenly find themselves with the weaker stack protector setup without even realizing. The solution here is to just rename not just the old RECULAR stack protector option, but also the strong one. This does that by just removing the CC_ prefix entirely for the user choices, because it really is not about the compiler support (the compiler support now instead automatially impacts _visibility_ of the options to users). This results in "make oldconfig" actually asking the user for their choice, so that we don't have any silent subtle security model changes. The end result would generally look like this: CONFIG_HAVE_CC_STACKPROTECTOR=y CONFIG_CC_HAS_STACKPROTECTOR_NONE=y CONFIG_STACKPROTECTOR=y CONFIG_STACKPROTECTOR_STRONG=y CONFIG_CC_HAS_SANE_STACKPROTECTOR=y where the "CC_" versions really are about internal compiler infrastructure, not the user selections. Acked-by: Masahiro Yamada Signed-off-by: Linus Torvalds --- arch/x86/entry/entry_32.S | 2 +- arch/x86/entry/entry_64.S | 2 +- arch/x86/include/asm/processor.h | 2 +- arch/x86/include/asm/segment.h | 2 +- arch/x86/include/asm/stackprotector.h | 6 +++--- arch/x86/kernel/asm-offsets.c | 2 +- arch/x86/kernel/asm-offsets_32.c | 2 +- arch/x86/kernel/asm-offsets_64.c | 2 +- arch/x86/kernel/cpu/common.c | 2 +- arch/x86/kernel/head_32.S | 2 +- 10 files changed, 12 insertions(+), 12 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index bef8e2b202a8..2582881d19ce 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -239,7 +239,7 @@ ENTRY(__switch_to_asm) movl %esp, TASK_threadsp(%eax) movl TASK_threadsp(%edx), %esp -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR movl TASK_stack_canary(%edx), %ebx movl %ebx, PER_CPU_VAR(stack_canary)+stack_canary_offset #endif diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 3166b9674429..73a522d53b53 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -357,7 +357,7 @@ ENTRY(__switch_to_asm) movq %rsp, TASK_threadsp(%rdi) movq TASK_threadsp(%rsi), %rsp -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR movq TASK_stack_canary(%rsi), %rbx movq %rbx, PER_CPU_VAR(irq_stack_union)+stack_canary_offset #endif diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index e28add6b791f..cfd29ee8c3da 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -412,7 +412,7 @@ extern asmlinkage void ignore_sysret(void); void save_fsgs_for_kvm(void); #endif #else /* X86_64 */ -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR /* * Make sure stack canary segment base is cached-aligned: * "For Intel Atom processors, avoid non zero segment base address diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h index 8f09012b92e7..e293c122d0d5 100644 --- a/arch/x86/include/asm/segment.h +++ b/arch/x86/include/asm/segment.h @@ -146,7 +146,7 @@ # define __KERNEL_PERCPU 0 #endif -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR # define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8) #else # define __KERNEL_STACK_CANARY 0 diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h index 371b3a4af000..8ec97a62c245 100644 --- a/arch/x86/include/asm/stackprotector.h +++ b/arch/x86/include/asm/stackprotector.h @@ -34,7 +34,7 @@ #ifndef _ASM_STACKPROTECTOR_H #define _ASM_STACKPROTECTOR_H 1 -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR #include #include @@ -105,7 +105,7 @@ static inline void load_stack_canary_segment(void) #endif } -#else /* CC_STACKPROTECTOR */ +#else /* STACKPROTECTOR */ #define GDT_STACK_CANARY_INIT @@ -121,5 +121,5 @@ static inline void load_stack_canary_segment(void) #endif } -#endif /* CC_STACKPROTECTOR */ +#endif /* STACKPROTECTOR */ #endif /* _ASM_STACKPROTECTOR_H */ diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index 76417a9aab73..dcb008c320fe 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -32,7 +32,7 @@ void common(void) { BLANK(); OFFSET(TASK_threadsp, task_struct, thread.sp); -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR OFFSET(TASK_stack_canary, task_struct, stack_canary); #endif diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c index f91ba53e06c8..a4a3be399f4b 100644 --- a/arch/x86/kernel/asm-offsets_32.c +++ b/arch/x86/kernel/asm-offsets_32.c @@ -50,7 +50,7 @@ void foo(void) DEFINE(TSS_sysenter_sp0, offsetof(struct cpu_entry_area, tss.x86_tss.sp0) - offsetofend(struct cpu_entry_area, entry_stack_page.stack)); -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR BLANK(); OFFSET(stack_canary_offset, stack_canary, canary); #endif diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c index bf51e51d808d..b2dcd161f514 100644 --- a/arch/x86/kernel/asm-offsets_64.c +++ b/arch/x86/kernel/asm-offsets_64.c @@ -69,7 +69,7 @@ int main(void) OFFSET(TSS_sp1, tss_struct, x86_tss.sp1); BLANK(); -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR DEFINE(stack_canary_offset, offsetof(union irq_stack_union, stack_canary)); BLANK(); #endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 910b47ee8078..0df7151cfef4 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1599,7 +1599,7 @@ DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) = (unsigned long)&init_thread_union + THREAD_SIZE; EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack); -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary); #endif diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index b59e4fb40fd9..abe6df15a8fb 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -375,7 +375,7 @@ ENDPROC(startup_32_smp) */ __INIT setup_once: -#ifdef CONFIG_CC_STACKPROTECTOR +#ifdef CONFIG_STACKPROTECTOR /* * Configure the stack canary. The linker can't handle this by * relocation. Manually set base address in stack canary -- cgit v1.2.3-59-g8ed1b