diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/Kconfig | 23 | ||||
| -rw-r--r-- | arch/x86/Kconfig.debug | 1 | ||||
| -rw-r--r-- | arch/x86/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/pda.h | 4 | ||||
| -rw-r--r-- | arch/x86/include/asm/system.h | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/process_64.c | 13 | ||||
| -rw-r--r-- | arch/x86/mm/fault.c | 7 |
8 files changed, 39 insertions, 18 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 0f44add3e0b7..615668d87bfd 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1325,13 +1325,17 @@ config SECCOMP If unsure, say Y. Only embedded should say N here. +config CC_STACKPROTECTOR_ALL + bool + config CC_STACKPROTECTOR bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)" - depends on X86_64 && EXPERIMENTAL && BROKEN + depends on X86_64 + select CC_STACKPROTECTOR_ALL help - This option turns on the -fstack-protector GCC feature. This - feature puts, at the beginning of critical functions, a canary - value on the stack just before the return address, and validates + 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 @@ -1339,15 +1343,8 @@ config CC_STACKPROTECTOR 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. - -config CC_STACKPROTECTOR_ALL - bool "Use stack-protector for all functions" - depends on CC_STACKPROTECTOR - help - Normally, GCC only inserts the canary value protection for - functions that use large-ish on-stack buffers. By enabling - this option, GCC will be asked to do this for ALL functions. + detected and for those versions, this configuration option is + ignored. (and a warning is printed during bootup) source kernel/Kconfig.hz diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 10d6cc3fd052..28f111461ca8 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -117,6 +117,7 @@ config DEBUG_RODATA config DEBUG_RODATA_TEST bool "Testcase for the DEBUG_RODATA feature" depends on DEBUG_RODATA + default y help This option enables a testcase for the DEBUG_RODATA feature as well as for the change_page_attr() infrastructure. diff --git a/arch/x86/Makefile b/arch/x86/Makefile index d1a47adb5aec..cacee981d166 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -73,7 +73,7 @@ else stackp := $(CONFIG_SHELL) $(srctree)/scripts/gcc-x86_64-has-stack-protector.sh stackp-$(CONFIG_CC_STACKPROTECTOR) := $(shell $(stackp) \ - "$(CC)" -fstack-protector ) + "$(CC)" "-fstack-protector -DGCC_HAS_SP" ) stackp-$(CONFIG_CC_STACKPROTECTOR_ALL) += $(shell $(stackp) \ "$(CC)" -fstack-protector-all ) diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h index 2fbfff88df37..3fea2fdb3302 100644 --- a/arch/x86/include/asm/pda.h +++ b/arch/x86/include/asm/pda.h @@ -16,11 +16,9 @@ struct x8664_pda { unsigned long oldrsp; /* 24 user rsp for system call */ int irqcount; /* 32 Irq nesting counter. Starts -1 */ unsigned int cpunumber; /* 36 Logical CPU number */ -#ifdef CONFIG_CC_STACKPROTECTOR unsigned long stack_canary; /* 40 stack canary value */ /* gcc-ABI: this canary MUST be at offset 40!!! */ -#endif char *irqstackptr; short nodenumber; /* number of current node (32k max) */ short in_bootmem; /* pda lives in bootmem */ @@ -134,4 +132,6 @@ do { \ #define PDA_STACKOFFSET (5*8) +#define refresh_stack_canary() write_pda(stack_canary, current->stack_canary) + #endif /* _ASM_X86_PDA_H */ diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h index 8e626ea33a1a..2f6340a44291 100644 --- a/arch/x86/include/asm/system.h +++ b/arch/x86/include/asm/system.h @@ -95,6 +95,8 @@ do { \ ".globl thread_return\n" \ "thread_return:\n\t" \ "movq %%gs:%P[pda_pcurrent],%%rsi\n\t" \ + "movq %P[task_canary](%%rsi),%%r8\n\t" \ + "movq %%r8,%%gs:%P[pda_canary]\n\t" \ "movq %P[thread_info](%%rsi),%%r8\n\t" \ LOCK_PREFIX "btr %[tif_fork],%P[ti_flags](%%r8)\n\t" \ "movq %%rax,%%rdi\n\t" \ @@ -106,7 +108,9 @@ do { \ [ti_flags] "i" (offsetof(struct thread_info, flags)), \ [tif_fork] "i" (TIF_FORK), \ [thread_info] "i" (offsetof(struct task_struct, stack)), \ - [pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent)) \ + [task_canary] "i" (offsetof(struct task_struct, stack_canary)),\ + [pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent)), \ + [pda_canary] "i" (offsetof(struct x8664_pda, stack_canary))\ : "memory", "cc" __EXTRA_CLOBBER) #endif diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index d364df03c1d6..eb074530c7d3 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -23,6 +23,7 @@ nostackp := $(call cc-option, -fno-stack-protector) CFLAGS_vsyscall_64.o := $(PROFILING) -g0 $(nostackp) CFLAGS_hpet.o := $(nostackp) CFLAGS_tsc.o := $(nostackp) +CFLAGS_paravirt.o := $(nostackp) obj-y := process_$(BITS).o signal.o entry_$(BITS).o obj-y += traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 416fb9282f4f..efb0396e19bf 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -16,6 +16,7 @@ #include <stdarg.h> +#include <linux/stackprotector.h> #include <linux/cpu.h> #include <linux/errno.h> #include <linux/sched.h> @@ -111,6 +112,17 @@ static inline void play_dead(void) void cpu_idle(void) { current_thread_info()->status |= TS_POLLING; + + /* + * If we're the non-boot CPU, nothing set the PDA stack + * canary up for us - and if we are the boot CPU we have + * a 0 stack canary. This is a good place for updating + * it, as we wont ever return from this function (so the + * invalid canaries already on the stack wont ever + * trigger): + */ + boot_init_stack_canary(); + /* endless idle loop with no priority at all */ while (1) { tick_nohz_stop_sched_tick(1); @@ -621,7 +633,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) (unsigned long)task_stack_page(next_p) + THREAD_SIZE - PDA_STACKOFFSET); #ifdef CONFIG_CC_STACKPROTECTOR - write_pda(stack_canary, next_p->stack_canary); /* * Build time only check to make sure the stack_canary is at * offset 40 in the pda; this is a gcc ABI requirement diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 57ec8c86a877..4c056b5d6a95 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -26,6 +26,7 @@ #include <linux/kprobes.h> #include <linux/uaccess.h> #include <linux/kdebug.h> +#include <linux/magic.h> #include <asm/system.h> #include <asm/desc.h> @@ -589,6 +590,8 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) unsigned long address; int write, si_code; int fault; + unsigned long *stackend; + #ifdef CONFIG_X86_64 unsigned long flags; int sig; @@ -842,6 +845,10 @@ no_context: show_fault_oops(regs, error_code, address); + stackend = end_of_stack(tsk); + if (*stackend != STACK_END_MAGIC) + printk(KERN_ALERT "Thread overran stack, or stack corrupted\n"); + tsk->thread.cr2 = address; tsk->thread.trap_no = 14; tsk->thread.error_code = error_code; |