Commit 0d73c3f8 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Russell King
Browse files

ARM: 8772/1: kprobes: Prohibit kprobes on get_user functions 



Since do_undefinstr() uses get_user to get the undefined
instruction, it can be called before kprobes processes
recursive check. This can cause an infinit recursive
exception.
Prohibit probing on get_user functions.

Fixes: 24ba613c ("ARM kprobes: core code")
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent eb0146da

arch/arm/include/asm/assembler.h

+10 −0
Original line number Diff line number Diff line
@@ -536,4 +536,14 @@ THUMB( orr \reg , \reg , #PSR_T_BIT ) 
#endif

	.endm



#ifdef CONFIG_KPROBES

#define _ASM_NOKPROBE(entry)				\

	.pushsection "_kprobe_blacklist", "aw" ;	\

	.balign 4 ;					\

	.long entry;					\

	.popsection

#else

#define _ASM_NOKPROBE(entry)

#endif



#endif /* __ASM_ASSEMBLER_H__ */

arch/arm/lib/getuser.S

+10 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ ENTRY(__get_user_1) 
	mov	r0, #0

	ret	lr

ENDPROC(__get_user_1)

_ASM_NOKPROBE(__get_user_1)



ENTRY(__get_user_2)

	check_uaccess r0, 2, r1, r2, __get_user_bad
@@ -58,6 +59,7 @@ rb .req r0 
	mov	r0, #0

	ret	lr

ENDPROC(__get_user_2)

_ASM_NOKPROBE(__get_user_2)



ENTRY(__get_user_4)

	check_uaccess r0, 4, r1, r2, __get_user_bad
@@ -65,6 +67,7 @@ ENTRY(__get_user_4) 
	mov	r0, #0

	ret	lr

ENDPROC(__get_user_4)

_ASM_NOKPROBE(__get_user_4)



ENTRY(__get_user_8)

	check_uaccess r0, 8, r1, r2, __get_user_bad8
@@ -78,6 +81,7 @@ ENTRY(__get_user_8) 
	mov	r0, #0

	ret	lr

ENDPROC(__get_user_8)

_ASM_NOKPROBE(__get_user_8)



#ifdef __ARMEB__

ENTRY(__get_user_32t_8)
@@ -91,6 +95,7 @@ ENTRY(__get_user_32t_8) 
	mov	r0, #0

	ret	lr

ENDPROC(__get_user_32t_8)

_ASM_NOKPROBE(__get_user_32t_8)



ENTRY(__get_user_64t_1)

	check_uaccess r0, 1, r1, r2, __get_user_bad8
@@ -98,6 +103,7 @@ ENTRY(__get_user_64t_1) 
	mov	r0, #0

	ret	lr

ENDPROC(__get_user_64t_1)

_ASM_NOKPROBE(__get_user_64t_1)



ENTRY(__get_user_64t_2)

	check_uaccess r0, 2, r1, r2, __get_user_bad8
@@ -114,6 +120,7 @@ rb .req r0 
	mov	r0, #0

	ret	lr

ENDPROC(__get_user_64t_2)

_ASM_NOKPROBE(__get_user_64t_2)



ENTRY(__get_user_64t_4)

	check_uaccess r0, 4, r1, r2, __get_user_bad8
@@ -121,6 +128,7 @@ ENTRY(__get_user_64t_4) 
	mov	r0, #0

	ret	lr

ENDPROC(__get_user_64t_4)

_ASM_NOKPROBE(__get_user_64t_4)

#endif



__get_user_bad8:
@@ -131,6 +139,8 @@ __get_user_bad: 
	ret	lr

ENDPROC(__get_user_bad)

ENDPROC(__get_user_bad8)

_ASM_NOKPROBE(__get_user_bad)

_ASM_NOKPROBE(__get_user_bad8)



.pushsection __ex_table, "a"

	.long	1b, __get_user_bad

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