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Commit e59d1b0a authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

x86-32, smap: Add STAC/CLAC instructions to 32-bit kernel entry 



The changes to entry_32.S got missed in checkin:

63bcff2a x86, smap: Add STAC and CLAC instructions to control user space access

The resulting kernel was largely functional but SMAP protection could
have been bypassed.

Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1348256595-29119-9-git-send-email-hpa@linux.intel.com
parent 5e88353d

arch/x86/kernel/entry_32.S

+26 −0
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ 
#include <asm/cpufeature.h>

#include <asm/alternative-asm.h>

#include <asm/asm.h>

#include <asm/smap.h>



/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this.  */

#include <linux/elf-em.h>
@@ -407,7 +408,9 @@ sysenter_past_esp: 
 */

	cmpl $__PAGE_OFFSET-3,%ebp

	jae syscall_fault

	ASM_STAC

1:	movl (%ebp),%ebp

	ASM_CLAC

	movl %ebp,PT_EBP(%esp)

	_ASM_EXTABLE(1b,syscall_fault)
@@ -488,6 +491,7 @@ ENDPROC(ia32_sysenter_target) 
	# system call handler stub

ENTRY(system_call)

	RING0_INT_FRAME			# can't unwind into user space anyway

	ASM_CLAC

	pushl_cfi %eax			# save orig_eax

	SAVE_ALL

	GET_THREAD_INFO(%ebp)
@@ -670,6 +674,7 @@ END(syscall_exit_work) 


	RING0_INT_FRAME			# can't unwind into user space anyway

syscall_fault:

	ASM_CLAC

	GET_THREAD_INFO(%ebp)

	movl $-EFAULT,PT_EAX(%esp)

	jmp resume_userspace
@@ -825,6 +830,7 @@ END(interrupt) 
 */

	.p2align CONFIG_X86_L1_CACHE_SHIFT

common_interrupt:

	ASM_CLAC

	addl $-0x80,(%esp)	/* Adjust vector into the [-256,-1] range */

	SAVE_ALL

	TRACE_IRQS_OFF
@@ -841,6 +847,7 @@ ENDPROC(common_interrupt) 
#define BUILD_INTERRUPT3(name, nr, fn)	\

ENTRY(name)				\

	RING0_INT_FRAME;		\

	ASM_CLAC;			\

	pushl_cfi $~(nr);		\

	SAVE_ALL;			\

	TRACE_IRQS_OFF			\
@@ -857,6 +864,7 @@ ENDPROC(name) 


ENTRY(coprocessor_error)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $0

	pushl_cfi $do_coprocessor_error

	jmp error_code
@@ -865,6 +873,7 @@ END(coprocessor_error) 


ENTRY(simd_coprocessor_error)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $0

#ifdef CONFIG_X86_INVD_BUG

	/* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */
@@ -886,6 +895,7 @@ END(simd_coprocessor_error) 


ENTRY(device_not_available)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $-1			# mark this as an int

	pushl_cfi $do_device_not_available

	jmp error_code
@@ -906,6 +916,7 @@ END(native_irq_enable_sysexit) 


ENTRY(overflow)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $0

	pushl_cfi $do_overflow

	jmp error_code
@@ -914,6 +925,7 @@ END(overflow) 


ENTRY(bounds)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $0

	pushl_cfi $do_bounds

	jmp error_code
@@ -922,6 +934,7 @@ END(bounds) 


ENTRY(invalid_op)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $0

	pushl_cfi $do_invalid_op

	jmp error_code
@@ -930,6 +943,7 @@ END(invalid_op) 


ENTRY(coprocessor_segment_overrun)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $0

	pushl_cfi $do_coprocessor_segment_overrun

	jmp error_code
@@ -938,6 +952,7 @@ END(coprocessor_segment_overrun) 


ENTRY(invalid_TSS)

	RING0_EC_FRAME

	ASM_CLAC

	pushl_cfi $do_invalid_TSS

	jmp error_code

	CFI_ENDPROC
@@ -945,6 +960,7 @@ END(invalid_TSS) 


ENTRY(segment_not_present)

	RING0_EC_FRAME

	ASM_CLAC

	pushl_cfi $do_segment_not_present

	jmp error_code

	CFI_ENDPROC
@@ -952,6 +968,7 @@ END(segment_not_present) 


ENTRY(stack_segment)

	RING0_EC_FRAME

	ASM_CLAC

	pushl_cfi $do_stack_segment

	jmp error_code

	CFI_ENDPROC
@@ -959,6 +976,7 @@ END(stack_segment) 


ENTRY(alignment_check)

	RING0_EC_FRAME

	ASM_CLAC

	pushl_cfi $do_alignment_check

	jmp error_code

	CFI_ENDPROC
@@ -966,6 +984,7 @@ END(alignment_check) 


ENTRY(divide_error)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $0			# no error code

	pushl_cfi $do_divide_error

	jmp error_code
@@ -975,6 +994,7 @@ END(divide_error) 
#ifdef CONFIG_X86_MCE

ENTRY(machine_check)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $0

	pushl_cfi machine_check_vector

	jmp error_code
@@ -984,6 +1004,7 @@ END(machine_check) 


ENTRY(spurious_interrupt_bug)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $0

	pushl_cfi $do_spurious_interrupt_bug

	jmp error_code
@@ -1207,6 +1228,7 @@ return_to_handler: 


ENTRY(page_fault)

	RING0_EC_FRAME

	ASM_CLAC

	pushl_cfi $do_page_fault

	ALIGN

error_code:
@@ -1279,6 +1301,7 @@ END(page_fault) 


ENTRY(debug)

	RING0_INT_FRAME

	ASM_CLAC

	cmpl $ia32_sysenter_target,(%esp)

	jne debug_stack_correct

	FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn
@@ -1303,6 +1326,7 @@ END(debug) 
 */

ENTRY(nmi)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi %eax

	movl %ss, %eax

	cmpw $__ESPFIX_SS, %ax
@@ -1373,6 +1397,7 @@ END(nmi) 


ENTRY(int3)

	RING0_INT_FRAME

	ASM_CLAC

	pushl_cfi $-1			# mark this as an int

	SAVE_ALL

	TRACE_IRQS_OFF
@@ -1393,6 +1418,7 @@ END(general_protection) 
#ifdef CONFIG_KVM_GUEST

ENTRY(async_page_fault)

	RING0_EC_FRAME

	ASM_CLAC

	pushl_cfi $do_async_page_fault

	jmp error_code

	CFI_ENDPROC