diff options
| -rw-r--r-- | arch/x86/include/asm/stackprotector.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/system.h | 8 | ||||
| -rw-r--r-- | arch/x86/kernel/head_32.S | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/process_32.c | 10 | ||||
| -rw-r--r-- | arch/x86/kernel/process_64.c | 11 |
5 files changed, 20 insertions, 12 deletions
diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h index fa7e5bd6fbe8..c2d742c6e15f 100644 --- a/arch/x86/include/asm/stackprotector.h +++ b/arch/x86/include/asm/stackprotector.h @@ -85,7 +85,7 @@ static __always_inline void boot_init_stack_canary(void) static inline void setup_stack_canary_segment(int cpu) { #ifdef CONFIG_X86_32 - unsigned long canary = (unsigned long)&per_cpu(stack_canary, cpu); + unsigned long canary = (unsigned long)&per_cpu(stack_canary, cpu) - 20; struct desc_struct *gdt_table = get_cpu_gdt_table(cpu); struct desc_struct desc; diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h index 2692ee8ef031..7a80f72bec47 100644 --- a/arch/x86/include/asm/system.h +++ b/arch/x86/include/asm/system.h @@ -25,13 +25,11 @@ struct task_struct *__switch_to(struct task_struct *prev, #ifdef CONFIG_CC_STACKPROTECTOR #define __switch_canary \ - "movl "__percpu_arg([current_task])",%%ebx\n\t" \ - "movl %P[task_canary](%%ebx),%%ebx\n\t" \ - "movl %%ebx,"__percpu_arg([stack_canary])"\n\t" + "movl %P[task_canary](%[next]), %%ebx\n\t" \ + "movl %%ebx, "__percpu_arg([stack_canary])"\n\t" #define __switch_canary_oparam \ , [stack_canary] "=m" (per_cpu_var(stack_canary)) #define __switch_canary_iparam \ - , [current_task] "m" (per_cpu_var(current_task)) \ , [task_canary] "i" (offsetof(struct task_struct, stack_canary)) #else /* CC_STACKPROTECTOR */ #define __switch_canary @@ -60,9 +58,9 @@ do { \ "movl %[next_sp],%%esp\n\t" /* restore ESP */ \ "movl $1f,%[prev_ip]\n\t" /* save EIP */ \ "pushl %[next_ip]\n\t" /* restore EIP */ \ + __switch_canary \ "jmp __switch_to\n" /* regparm call */ \ "1:\t" \ - __switch_canary \ "popl %%ebp\n\t" /* restore EBP */ \ "popfl\n" /* restore flags */ \ \ diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 924e31615fb6..cf21fd0cf6ac 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -447,6 +447,7 @@ is386: movl $2,%ecx # set MP jne 1f movl $per_cpu__gdt_page,%eax movl $per_cpu__stack_canary,%ecx + subl $20, %ecx movw %cx, 8 * GDT_ENTRY_STACK_CANARY + 2(%eax) shrl $16, %ecx movb %cl, 8 * GDT_ENTRY_STACK_CANARY + 4(%eax) diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 9a62383e7c3c..b50604bb1e41 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -11,6 +11,7 @@ #include <stdarg.h> +#include <linux/stackprotector.h> #include <linux/cpu.h> #include <linux/errno.h> #include <linux/sched.h> @@ -91,6 +92,15 @@ void cpu_idle(void) { int cpu = smp_processor_id(); + /* + * If we're the non-boot CPU, nothing set the stack canary up + * for us. CPU0 already has it initialized but no harm in + * doing it again. 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(); + current_thread_info()->status |= TS_POLLING; /* endless idle loop with no priority at all */ diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 8eb169e45584..836ef6575f01 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -120,12 +120,11 @@ 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): + * If we're the non-boot CPU, nothing set the stack canary up + * for us. CPU0 already has it initialized but no harm in + * doing it again. 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(); |