diff options
| -rw-r--r-- | arch/x86/include/asm/processor.h | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/process.c | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 8 |
3 files changed, 13 insertions, 1 deletions
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 7cd01b71b5bdc..50a6dc871cc08 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -299,8 +299,9 @@ struct tss_struct { #ifdef CONFIG_X86_32 /* - * Space for the temporary SYSENTER stack: + * Space for the temporary SYSENTER stack. */ + unsigned long SYSENTER_stack_canary; unsigned long SYSENTER_stack[64]; #endif diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 9f7c21c22477e..ee9a9792caeb3 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -57,6 +57,9 @@ __visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = { */ .io_bitmap = { [0 ... IO_BITMAP_LONGS] = ~0 }, #endif +#ifdef CONFIG_X86_32 + .SYSENTER_stack_canary = STACK_END_MAGIC, +#endif }; EXPORT_PER_CPU_SYMBOL(cpu_tss); diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index b0ddb81926f92..49e2e775f507a 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -713,6 +713,14 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code) debug_stack_usage_dec(); exit: +#if defined(CONFIG_X86_32) + /* + * This is the most likely code path that involves non-trivial use + * of the SYSENTER stack. Check that we haven't overrun it. + */ + WARN(this_cpu_read(cpu_tss.SYSENTER_stack_canary) != STACK_END_MAGIC, + "Overran or corrupted SYSENTER stack\n"); +#endif ist_exit(regs); } NOKPROBE_SYMBOL(do_debug); |