lkml.org 
[lkml]   [2018]   [Jan]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH RFC 2/4] x86/arch_prctl: add ARCH_GET_NOPTI and ARCH_SET_NOPTI to enable/disable PTI
    On Mon, 8 Jan 2018, Willy Tarreau wrote:
    > This allows to report the current state of the PTI protection and to
    > enable or disable it for the current task.
    >
    > Signed-off-by: Willy Tarreau <w@1wt.eu>
    > ---
    > arch/x86/include/uapi/asm/prctl.h | 3 +++
    > arch/x86/kernel/process_64.c | 24 ++++++++++++++++++++++++
    > 2 files changed, 27 insertions(+)
    >
    > diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
    > index 5a6aac9..1f1b5bc 100644
    > --- a/arch/x86/include/uapi/asm/prctl.h
    > +++ b/arch/x86/include/uapi/asm/prctl.h
    > @@ -10,6 +10,9 @@
    > #define ARCH_GET_CPUID 0x1011
    > #define ARCH_SET_CPUID 0x1012
    >
    > +#define ARCH_GET_NOPTI 0x1021
    > +#define ARCH_SET_NOPTI 0x1022
    > +
    > #define ARCH_MAP_VDSO_X32 0x2001
    > #define ARCH_MAP_VDSO_32 0x2002
    > #define ARCH_MAP_VDSO_64 0x2003
    > diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
    > index c754662..1686d3d 100644
    > --- a/arch/x86/kernel/process_64.c
    > +++ b/arch/x86/kernel/process_64.c
    > @@ -654,6 +654,30 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
    > ret = put_user(base, (unsigned long __user *)arg2);
    > break;
    > }
    > + case ARCH_GET_NOPTI: {
    > + unsigned long flag;
    > +
    > + printk(KERN_DEBUG "get1: task=%p ti=%p fl=%16lx\n", task, task_thread_info(task), task_thread_info(task)->flags);
    > + flag = !!(task_thread_info(task)->flags & _TIF_NOPTI);
    > + ret = put_user(flag, (unsigned long __user *)arg2);
    > + break;

    Per task is really an odd choice. That should be per process I think, but
    that of course needs synchronization of some form. Aside of that we need to
    think about fork().

    Thanks,

    tglx


    \
     
     \ /
      Last update: 2018-01-14 23:17    [W:4.051 / U:0.124 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site