diff options
Diffstat (limited to 'arch/x86/kernel/ldt.c')
| -rw-r--r-- | arch/x86/kernel/ldt.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c index ebc98739892..dcbbaa165bd 100644 --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -20,6 +20,8 @@ #include <asm/mmu_context.h> #include <asm/syscalls.h> +int sysctl_ldt16 = 0; + #ifdef CONFIG_SMP static void flush_ldt(void *current_mm) { @@ -229,6 +231,17 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode) } } + /* + * On x86-64 we do not support 16-bit segments due to + * IRET leaking the high bits of the kernel stack address. + */ +#ifdef CONFIG_X86_64 + if (!ldt_info.seg_32bit && !sysctl_ldt16) { + error = -EINVAL; + goto out_unlock; + } +#endif + fill_ldt(&ldt, &ldt_info); if (oldmode) ldt.avl = 0; |