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* [PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed()
@ 2021-07-31  2:50 Liang Wang
  2021-08-02 22:40 ` Luis Chamberlain
  2021-08-04  5:01 ` Kefeng Wang
  0 siblings, 2 replies; 4+ messages in thread
From: Liang Wang @ 2021-07-31  2:50 UTC (permalink / raw)
  To: palmerdabbelt, mcgrof, linux-kernel, gregkh, linux, linux-arm-kernel
  Cc: stable, wangliang101, wangle6, kepler.chenxin, nixiaoming,
	wangkefeng.wang

The physical address may exceed 32 bits on 32-bit systems with
more than 32 bits of physcial address,use PFN_PHYS() in devmem_is_allowed(),
or the physical address may overflow and be truncated.
We found this bug when mapping a high addresses through devmem tool,
when CONFIG_STRICT_DEVMEM is enabled on the ARM with ARM_LPAE and devmem
is used to map a high address that is not in the iomem address range,
an unexpected error indicating no permission is returned.

This bug was initially introduced from v2.6.37, and the function was moved
to lib when v5.11.

Cc: Luis Chamberlain <mcgrof@kernel.org>
Fixes: 087aaffcdf9c ("ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem")
Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()")
Cc: stable@vger.kernel.org # v2.6.37
Signed-off-by: Liang Wang <wangliang101@huawei.com>
---
v3: update changelog suggested by Luis Chamberlain <mcgrof@kernel.org>
 lib/devmem_is_allowed.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/devmem_is_allowed.c b/lib/devmem_is_allowed.c
index c0d67c541849..60be9e24bd57 100644
--- a/lib/devmem_is_allowed.c
+++ b/lib/devmem_is_allowed.c
@@ -19,7 +19,7 @@
  */
 int devmem_is_allowed(unsigned long pfn)
 {
-	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
+	if (iomem_is_exclusive(PFN_PHYS(pfn)))
 		return 0;
 	if (!page_is_ram(pfn))
 		return 1;
-- 
2.32.0


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed()
  2021-07-31  2:50 [PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed() Liang Wang
@ 2021-08-02 22:40 ` Luis Chamberlain
  2021-08-04  5:01 ` Kefeng Wang
  1 sibling, 0 replies; 4+ messages in thread
From: Luis Chamberlain @ 2021-08-02 22:40 UTC (permalink / raw)
  To: Liang Wang, Andrew Morton
  Cc: palmerdabbelt, linux-kernel, gregkh, linux, linux-arm-kernel,
	stable, wangle6, kepler.chenxin, nixiaoming, wangkefeng.wang

On Sat, Jul 31, 2021 at 10:50:57AM +0800, Liang Wang wrote:
> The physical address may exceed 32 bits on 32-bit systems with
> more than 32 bits of physcial address,use PFN_PHYS() in devmem_is_allowed(),
> or the physical address may overflow and be truncated.
> We found this bug when mapping a high addresses through devmem tool,
> when CONFIG_STRICT_DEVMEM is enabled on the ARM with ARM_LPAE and devmem
> is used to map a high address that is not in the iomem address range,
> an unexpected error indicating no permission is returned.
> 
> This bug was initially introduced from v2.6.37, and the function was moved
> to lib when v5.11.
> 
> Cc: Luis Chamberlain <mcgrof@kernel.org>
> Fixes: 087aaffcdf9c ("ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem")
> Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()")
> Cc: stable@vger.kernel.org # v2.6.37
> Signed-off-by: Liang Wang <wangliang101@huawei.com>

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>

  Luis

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed()
  2021-07-31  2:50 [PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed() Liang Wang
  2021-08-02 22:40 ` Luis Chamberlain
@ 2021-08-04  5:01 ` Kefeng Wang
  2021-08-04  5:14   ` Palmer Dabbelt
  1 sibling, 1 reply; 4+ messages in thread
From: Kefeng Wang @ 2021-08-04  5:01 UTC (permalink / raw)
  To: Liang Wang, palmerdabbelt, mcgrof, linux-kernel, gregkh, linux,
	linux-arm-kernel
  Cc: stable, wangle6, kepler.chenxin, nixiaoming


On 2021/7/31 10:50, Liang Wang wrote:
> The physical address may exceed 32 bits on 32-bit systems with
> more than 32 bits of physcial address,use PFN_PHYS() in devmem_is_allowed(),
> or the physical address may overflow and be truncated.
> We found this bug when mapping a high addresses through devmem tool,
> when CONFIG_STRICT_DEVMEM is enabled on the ARM with ARM_LPAE and devmem
> is used to map a high address that is not in the iomem address range,
> an unexpected error indicating no permission is returned.
>
> This bug was initially introduced from v2.6.37, and the function was moved
> to lib when v5.11.
>
> Cc: Luis Chamberlain <mcgrof@kernel.org>
> Fixes: 087aaffcdf9c ("ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem")
> Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()")
> Cc: stable@vger.kernel.org # v2.6.37
> Signed-off-by: Liang Wang <wangliang101@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed()
  2021-08-04  5:01 ` Kefeng Wang
@ 2021-08-04  5:14   ` Palmer Dabbelt
  0 siblings, 0 replies; 4+ messages in thread
From: Palmer Dabbelt @ 2021-08-04  5:14 UTC (permalink / raw)
  To: wangkefeng.wang
  Cc: wangliang101, mcgrof, linux-kernel, Greg KH, linux,
	linux-arm-kernel, stable, wangle6, kepler.chenxin, nixiaoming

On Tue, 03 Aug 2021 22:01:46 PDT (-0700), wangkefeng.wang@huawei.com wrote:
>
> On 2021/7/31 10:50, Liang Wang wrote:
>> The physical address may exceed 32 bits on 32-bit systems with
>> more than 32 bits of physcial address,use PFN_PHYS() in devmem_is_allowed(),
>> or the physical address may overflow and be truncated.
>> We found this bug when mapping a high addresses through devmem tool,
>> when CONFIG_STRICT_DEVMEM is enabled on the ARM with ARM_LPAE and devmem
>> is used to map a high address that is not in the iomem address range,
>> an unexpected error indicating no permission is returned.
>>
>> This bug was initially introduced from v2.6.37, and the function was moved
>> to lib when v5.11.
>>
>> Cc: Luis Chamberlain <mcgrof@kernel.org>
>> Fixes: 087aaffcdf9c ("ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem")
>> Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()")
>> Cc: stable@vger.kernel.org # v2.6.37
>> Signed-off-by: Liang Wang <wangliang101@huawei.com>
> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>

Weird, it's still only your replies that are coming through.  Given that 
this only manifests on 32-bit Arm systems, I'm going to leave this up to 
them for now.

Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-08-04  5:14 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-07-31  2:50 [PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed() Liang Wang
2021-08-02 22:40 ` Luis Chamberlain
2021-08-04  5:01 ` Kefeng Wang
2021-08-04  5:14   ` Palmer Dabbelt

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