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* [PATCH] arm64: ensure __dump_instr() checks addr_limit
@ 2017-11-02 16:12 ` Mark Rutland
  0 siblings, 0 replies; 6+ messages in thread
From: Mark Rutland @ 2017-11-02 16:12 UTC (permalink / raw)
  To: linux-arm-kernel; +Cc: Mark Rutland, Catalin Marinas, Will Deacon, stable

It's possible for a user to deliberately trigger __dump_instr with a
chosen kernel address.

Let's avoid problems resulting from this by using get_user() rather than
__get_user(), ensuring that we don't erroneously access kernel memory.

Where we use __dump_instr() on kernel text, we already switch to
KERNEL_DS, so this shouldn't adversely affect those cases.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 60ffc30d5652810d ("arm64: Exception handling")
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
---
 arch/arm64/kernel/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 5ea4b85aee0e..8383af15a759 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -118,7 +118,7 @@ static void __dump_instr(const char *lvl, struct pt_regs *regs)
 	for (i = -4; i < 1; i++) {
 		unsigned int val, bad;
 
-		bad = __get_user(val, &((u32 *)addr)[i]);
+		bad = get_user(val, &((u32 *)addr)[i]);
 
 		if (!bad)
 			p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
-- 
2.11.0

^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH] arm64: ensure __dump_instr() checks addr_limit
@ 2017-11-02 16:12 ` Mark Rutland
  0 siblings, 0 replies; 6+ messages in thread
From: Mark Rutland @ 2017-11-02 16:12 UTC (permalink / raw)
  To: linux-arm-kernel

It's possible for a user to deliberately trigger __dump_instr with a
chosen kernel address.

Let's avoid problems resulting from this by using get_user() rather than
__get_user(), ensuring that we don't erroneously access kernel memory.

Where we use __dump_instr() on kernel text, we already switch to
KERNEL_DS, so this shouldn't adversely affect those cases.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 60ffc30d5652810d ("arm64: Exception handling")
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: stable at vger.kernel.org
---
 arch/arm64/kernel/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 5ea4b85aee0e..8383af15a759 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -118,7 +118,7 @@ static void __dump_instr(const char *lvl, struct pt_regs *regs)
 	for (i = -4; i < 1; i++) {
 		unsigned int val, bad;
 
-		bad = __get_user(val, &((u32 *)addr)[i]);
+		bad = get_user(val, &((u32 *)addr)[i]);
 
 		if (!bad)
 			p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
-- 
2.11.0

^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH] arm64: ensure __dump_instr() checks addr_limit
  2017-11-02 16:12 ` Mark Rutland
@ 2017-11-02 17:07   ` Will Deacon
  -1 siblings, 0 replies; 6+ messages in thread
From: Will Deacon @ 2017-11-02 17:07 UTC (permalink / raw)
  To: Mark Rutland; +Cc: linux-arm-kernel, Catalin Marinas, stable

On Thu, Nov 02, 2017 at 04:12:03PM +0000, Mark Rutland wrote:
> It's possible for a user to deliberately trigger __dump_instr with a
> chosen kernel address.
> 
> Let's avoid problems resulting from this by using get_user() rather than
> __get_user(), ensuring that we don't erroneously access kernel memory.
> 
> Where we use __dump_instr() on kernel text, we already switch to
> KERNEL_DS, so this shouldn't adversely affect those cases.
> 
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Fixes: 60ffc30d5652810d ("arm64: Exception handling")
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: stable@vger.kernel.org
> ---
>  arch/arm64/kernel/traps.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Acked-by: Will Deacon <will.deacon@arm.com>

Catalin, can you take this as a fix please?

Will

> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index 5ea4b85aee0e..8383af15a759 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -118,7 +118,7 @@ static void __dump_instr(const char *lvl, struct pt_regs *regs)
>  	for (i = -4; i < 1; i++) {
>  		unsigned int val, bad;
>  
> -		bad = __get_user(val, &((u32 *)addr)[i]);
> +		bad = get_user(val, &((u32 *)addr)[i]);
>  
>  		if (!bad)
>  			p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
> -- 
> 2.11.0
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread
* [PATCH] arm64: ensure __dump_instr() checks addr_limit
@ 2017-11-02 17:07   ` Will Deacon
  0 siblings, 0 replies; 6+ messages in thread
From: Will Deacon @ 2017-11-02 17:07 UTC (permalink / raw)
  To: linux-arm-kernel

On Thu, Nov 02, 2017 at 04:12:03PM +0000, Mark Rutland wrote:
> It's possible for a user to deliberately trigger __dump_instr with a
> chosen kernel address.
> 
> Let's avoid problems resulting from this by using get_user() rather than
> __get_user(), ensuring that we don't erroneously access kernel memory.
> 
> Where we use __dump_instr() on kernel text, we already switch to
> KERNEL_DS, so this shouldn't adversely affect those cases.
> 
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Fixes: 60ffc30d5652810d ("arm64: Exception handling")
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: stable at vger.kernel.org
> ---
>  arch/arm64/kernel/traps.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Acked-by: Will Deacon <will.deacon@arm.com>

Catalin, can you take this as a fix please?

Will

> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index 5ea4b85aee0e..8383af15a759 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -118,7 +118,7 @@ static void __dump_instr(const char *lvl, struct pt_regs *regs)
>  	for (i = -4; i < 1; i++) {
>  		unsigned int val, bad;
>  
> -		bad = __get_user(val, &((u32 *)addr)[i]);
> +		bad = get_user(val, &((u32 *)addr)[i]);
>  
>  		if (!bad)
>  			p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
> -- 
> 2.11.0
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] arm64: ensure __dump_instr() checks addr_limit
  2017-11-02 16:12 ` Mark Rutland
@ 2017-11-02 18:31   ` Catalin Marinas
  -1 siblings, 0 replies; 6+ messages in thread
From: Catalin Marinas @ 2017-11-02 18:31 UTC (permalink / raw)
  To: Mark Rutland; +Cc: linux-arm-kernel, Will Deacon, stable

On Thu, Nov 02, 2017 at 04:12:03PM +0000, Mark Rutland wrote:
> It's possible for a user to deliberately trigger __dump_instr with a
> chosen kernel address.
> 
> Let's avoid problems resulting from this by using get_user() rather than
> __get_user(), ensuring that we don't erroneously access kernel memory.
> 
> Where we use __dump_instr() on kernel text, we already switch to
> KERNEL_DS, so this shouldn't adversely affect those cases.
> 
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Fixes: 60ffc30d5652810d ("arm64: Exception handling")
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: stable@vger.kernel.org

Queued for 4.14. Thanks.

-- 
Catalin

^ permalink raw reply	[flat|nested] 6+ messages in thread
* [PATCH] arm64: ensure __dump_instr() checks addr_limit
@ 2017-11-02 18:31   ` Catalin Marinas
  0 siblings, 0 replies; 6+ messages in thread
From: Catalin Marinas @ 2017-11-02 18:31 UTC (permalink / raw)
  To: linux-arm-kernel

On Thu, Nov 02, 2017 at 04:12:03PM +0000, Mark Rutland wrote:
> It's possible for a user to deliberately trigger __dump_instr with a
> chosen kernel address.
> 
> Let's avoid problems resulting from this by using get_user() rather than
> __get_user(), ensuring that we don't erroneously access kernel memory.
> 
> Where we use __dump_instr() on kernel text, we already switch to
> KERNEL_DS, so this shouldn't adversely affect those cases.
> 
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Fixes: 60ffc30d5652810d ("arm64: Exception handling")
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: stable at vger.kernel.org

Queued for 4.14. Thanks.

-- 
Catalin

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-11-02 18:31 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-11-02 16:12 [PATCH] arm64: ensure __dump_instr() checks addr_limit Mark Rutland
2017-11-02 16:12 ` Mark Rutland
2017-11-02 17:07 ` Will Deacon
2017-11-02 17:07   ` Will Deacon
2017-11-02 18:31 ` Catalin Marinas
2017-11-02 18:31   ` Catalin Marinas

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