-stable review patch. If anyone has any objections, please let us know.
------------------
From: Andi Kleen <[EMAIL PROTECTED]>
SYSENTER can cause a NT to be set which might cause crashes on the IRET
in the next task.
Following similar i386 patch from Linus.
Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>
[backport from Chuck Ebbert]
Signed-off-by: Chuck Ebbert <[EMAIL PROTECTED]>
Signed-off-by: Chris Wright <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
arch/x86_64/kernel/entry.S | 4 ++++
arch/x86_64/kernel/setup64.c | 4 ++++
include/asm-x86_64/system.h | 5 +++--
3 files changed, 11 insertions(+), 2 deletions(-)
--- linux-2.6.18.7.orig/arch/x86_64/kernel/entry.S
+++ linux-2.6.18.7/arch/x86_64/kernel/entry.S
@@ -146,6 +146,10 @@
/* rdi: prev */
ENTRY(ret_from_fork)
CFI_DEFAULT_STACK
+ push kernel_eflags(%rip)
+ CFI_ADJUST_CFA_OFFSET 4
+ popf # reset kernel eflags
+ CFI_ADJUST_CFA_OFFSET -4
call schedule_tail
GET_THREAD_INFO(%rcx)
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),threadinfo_flags(%rcx)
--- linux-2.6.18.7.orig/arch/x86_64/kernel/setup64.c
+++ linux-2.6.18.7/arch/x86_64/kernel/setup64.c
@@ -178,6 +178,8 @@ void __cpuinit check_efer(void)
}
}
+unsigned long kernel_eflags;
+
/*
* cpu_init() initializes state that is per-CPU. Some data is already
* initialized (naturally) in the bootstrap process, such as the GDT
@@ -290,4 +292,6 @@ void __cpuinit cpu_init (void)
set_debugreg(0UL, 7);
fpu_init();
+
+ raw_local_save_flags(kernel_eflags);
}
--- linux-2.6.18.7.orig/include/asm-x86_64/system.h
+++ linux-2.6.18.7/include/asm-x86_64/system.h
@@ -14,12 +14,13 @@
#define __RESTORE(reg,offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t"
/* frame pointer must be last for get_wchan */
-#define SAVE_CONTEXT "pushq %%rbp ; movq %%rsi,%%rbp\n\t"
-#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp\n\t"
+#define SAVE_CONTEXT "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"
+#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t"
#define __EXTRA_CLOBBER \
,"rcx","rbx","rdx","r8","r9","r10","r11","r12","r13","r14","r15"
+/* Save restore flags to clear handle leaking NT */
#define switch_to(prev,next,last) \
asm volatile(SAVE_CONTEXT
\
"movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */
\
--
-
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