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Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull x86 pti updates from Thomas Gleixner:
 "The speculative paranoia departement delivers a few more plugs for
  possible (probably theoretical) spectre/mds leaks"

* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tls: Fix possible spectre-v1 in do_get_thread_area()
  x86/ptrace: Fix possible spectre-v1 in ptrace_get_debugreg()
  x86/speculation/mds: Eliminate leaks by trace_hardirqs_on()
This commit is contained in:
Linus Torvalds 2019-07-08 12:23:00 -07:00
commit 223cea6a4f
3 changed files with 12 additions and 5 deletions
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4
arch/x86/include/asm/mwait.h
View File

@ -86,9 +86,9 @@ static inline void __mwaitx(unsigned long eax, unsigned long ebx,
static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
{
mds_idle_clear_cpu_buffers();
trace_hardirqs_on();
mds_idle_clear_cpu_buffers();
/* "mwait %eax, %ecx;" */
asm volatile("sti; .byte 0x0f, 0x01, 0xc9;"
:: "a" (eax), "c" (ecx));

4
arch/x86/kernel/ptrace.c
View File

@ -25,6 +25,7 @@
#include <linux/rcupdate.h>
#include <linux/export.h>
#include <linux/context_tracking.h>
#include <linux/nospec.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
@ -635,7 +636,8 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
unsigned long val = 0;
if (n < HBP_NUM) {
struct perf_event *bp = thread->ptrace_bps[n];
int index = array_index_nospec(n, HBP_NUM);
struct perf_event *bp = thread->ptrace_bps[index];
if (bp)
val = bp->hw.info.address;

9
arch/x86/kernel/tls.c
View File

@ -5,6 +5,7 @@
#include <linux/user.h>
#include <linux/regset.h>
#include <linux/syscalls.h>
#include <linux/nospec.h>
#include <linux/uaccess.h>
#include <asm/desc.h>
@ -220,6 +221,7 @@ int do_get_thread_area(struct task_struct *p, int idx,
struct user_desc __user *u_info)
{
struct user_desc info;
int index;
if (idx == -1 && get_user(idx, &u_info->entry_number))
return -EFAULT;
@ -227,8 +229,11 @@ int do_get_thread_area(struct task_struct *p, int idx,
if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
return -EINVAL;
fill_user_desc(&info, idx,
&p->thread.tls_array[idx - GDT_ENTRY_TLS_MIN]);
index = idx - GDT_ENTRY_TLS_MIN;
index = array_index_nospec(index,
GDT_ENTRY_TLS_MAX - GDT_ENTRY_TLS_MIN + 1);
fill_user_desc(&info, idx, &p->thread.tls_array[index]);
if (copy_to_user(u_info, &info, sizeof(info)))
return -EFAULT;