From: mhiramat@kernel.org (Masami Hiramatsu)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] arm: kprobes: Prohibit kprobes on get_user functions
Date: Sat, 24 Feb 2018 17:03:19 +0900 [thread overview]
Message-ID: <151945939903.11045.1486072728379559979.stgit@devbox> (raw)
In-Reply-To: <151945937038.11045.14421944772744094357.stgit@devbox>
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: 24ba613c9d6c ("ARM kprobes: core code")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/arm/include/asm/assembler.h | 8 ++++++++
arch/arm/lib/getuser.S | 10 ++++++++++
2 files changed, 18 insertions(+)
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index bc8d4bbd82e2..dd5e7f30eaed 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -536,4 +536,12 @@ 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
+#endif
+
#endif /* __ASM_ASSEMBLER_H__ */
diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S
index df73914e81c8..746e7801dcdf 100644
--- a/arch/arm/lib/getuser.S
+++ b/arch/arm/lib/getuser.S
@@ -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
next prev parent reply other threads:[~2018-02-24 8:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-24 8:02 [PATCH 1/2] arm: kprobes: Prohibit kprobes on do_undefinstr Masami Hiramatsu
2018-02-24 8:03 ` Masami Hiramatsu [this message]
2018-02-25 10:09 ` [PATCH 2/2] arm: kprobes: Prohibit kprobes on get_user functions kbuild test robot
2018-02-25 10:12 ` kbuild test robot
2018-02-25 12:21 ` Masami Hiramatsu
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