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* [PATCH] nvmem: core: add sanity check in nvmem_device_read()
@ 2020-08-04  9:13 Bingbu Cao
  2020-08-04  9:58 ` Sakari Ailus
  0 siblings, 1 reply; 5+ messages in thread
From: Bingbu Cao @ 2020-08-04  9:13 UTC (permalink / raw)
  To: srinivas.kandagatla, linux-kernel; +Cc: sakari.ailus, bingbu.cao, bingbu.cao

nvmem_device_read() could be called directly once nvmem device
registered, the sanity check should be done before call
nvmem_reg_read() as cell and sysfs read did now.

Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
---
 drivers/nvmem/core.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 927eb5f6003f..c9a77993f008 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1491,6 +1491,13 @@ int nvmem_device_read(struct nvmem_device *nvmem,
 	if (!nvmem)
 		return -EINVAL;
 
+	if (offset >= nvmem->size || bytes < nvmem->word_size)
+		return 0;
+
+	if (bytes + offset > nvmem->size)
+		bytes = nvmem->size - offset;
+
+	bytes = round_down(bytes, nvmem->word_size);
 	rc = nvmem_reg_read(nvmem, offset, buf, bytes);
 
 	if (rc)
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH] nvmem: core: add sanity check in nvmem_device_read()
  2020-08-04  9:13 [PATCH] nvmem: core: add sanity check in nvmem_device_read() Bingbu Cao
@ 2020-08-04  9:58 ` Sakari Ailus
  2020-08-04 10:03   ` Srinivas Kandagatla
  0 siblings, 1 reply; 5+ messages in thread
From: Sakari Ailus @ 2020-08-04  9:58 UTC (permalink / raw)
  To: Bingbu Cao; +Cc: srinivas.kandagatla, linux-kernel, bingbu.cao

Hi Bingbu,

Thank you for the patch.

On Tue, Aug 04, 2020 at 05:13:56PM +0800, Bingbu Cao wrote:
> nvmem_device_read() could be called directly once nvmem device
> registered, the sanity check should be done before call
> nvmem_reg_read() as cell and sysfs read did now.
> 
> Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
> ---
>  drivers/nvmem/core.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index 927eb5f6003f..c9a77993f008 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -1491,6 +1491,13 @@ int nvmem_device_read(struct nvmem_device *nvmem,
>  	if (!nvmem)
>  		return -EINVAL;
>  
> +	if (offset >= nvmem->size || bytes < nvmem->word_size)
> +		return 0;
> +
> +	if (bytes + offset > nvmem->size)
> +		bytes = nvmem->size - offset;

The check is relevant for nvmem_device_write(), too.

There are also other ways to access nvmem devices such as nvmem_cell_read
and others alike. Should they be considered as well?

> +
> +	bytes = round_down(bytes, nvmem->word_size);
>  	rc = nvmem_reg_read(nvmem, offset, buf, bytes);
>  
>  	if (rc)

-- 
Kind regards,

Sakari Ailus

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] nvmem: core: add sanity check in nvmem_device_read()
  2020-08-04  9:58 ` Sakari Ailus
@ 2020-08-04 10:03   ` Srinivas Kandagatla
  2020-08-04 10:44     ` Bingbu Cao
  0 siblings, 1 reply; 5+ messages in thread
From: Srinivas Kandagatla @ 2020-08-04 10:03 UTC (permalink / raw)
  To: Sakari Ailus, Bingbu Cao; +Cc: linux-kernel, bingbu.cao



On 04/08/2020 10:58, Sakari Ailus wrote:
> Hi Bingbu,
> 
> Thank you for the patch.
> 
> On Tue, Aug 04, 2020 at 05:13:56PM +0800, Bingbu Cao wrote:
>> nvmem_device_read() could be called directly once nvmem device
>> registered, the sanity check should be done before call
>> nvmem_reg_read() as cell and sysfs read did now.
>>
>> Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
>> ---
>>   drivers/nvmem/core.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
>> index 927eb5f6003f..c9a77993f008 100644
>> --- a/drivers/nvmem/core.c
>> +++ b/drivers/nvmem/core.c
>> @@ -1491,6 +1491,13 @@ int nvmem_device_read(struct nvmem_device *nvmem,
>>   	if (!nvmem)
>>   		return -EINVAL;
>>   
>> +	if (offset >= nvmem->size || bytes < nvmem->word_size)
>> +		return 0;
>> +
>> +	if (bytes + offset > nvmem->size)
>> +		bytes = nvmem->size - offset;
> 
> The check is relevant for nvmem_device_write(), too.
> 
> There are also other ways to access nvmem devices such as nvmem_cell_read
> and others alike. Should they be considered as well?

We should probably move these sanity checks to a common place like 
nvmem_reg_read() and nvmem_reg_write(), so the callers need not 
duplicate the same!

--srini

> 
>> +
>> +	bytes = round_down(bytes, nvmem->word_size);
>>   	rc = nvmem_reg_read(nvmem, offset, buf, bytes);
>>   
>>   	if (rc)
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] nvmem: core: add sanity check in nvmem_device_read()
  2020-08-04 10:03   ` Srinivas Kandagatla
@ 2020-08-04 10:44     ` Bingbu Cao
  2020-08-04 10:56       ` Sakari Ailus
  0 siblings, 1 reply; 5+ messages in thread
From: Bingbu Cao @ 2020-08-04 10:44 UTC (permalink / raw)
  To: Srinivas Kandagatla, Sakari Ailus, Bingbu Cao; +Cc: linux-kernel


On 8/4/20 6:03 PM, Srinivas Kandagatla wrote:
> 
> 
> On 04/08/2020 10:58, Sakari Ailus wrote:
>> Hi Bingbu,
>>
>> Thank you for the patch.
>>
>> On Tue, Aug 04, 2020 at 05:13:56PM +0800, Bingbu Cao wrote:
>>> nvmem_device_read() could be called directly once nvmem device
>>> registered, the sanity check should be done before call
>>> nvmem_reg_read() as cell and sysfs read did now.
>>>
>>> Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
>>> ---
>>>   drivers/nvmem/core.c | 7 +++++++
>>>   1 file changed, 7 insertions(+)
>>>
>>> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
>>> index 927eb5f6003f..c9a77993f008 100644
>>> --- a/drivers/nvmem/core.c
>>> +++ b/drivers/nvmem/core.c
>>> @@ -1491,6 +1491,13 @@ int nvmem_device_read(struct nvmem_device *nvmem,
>>>       if (!nvmem)
>>>           return -EINVAL;
>>>   +    if (offset >= nvmem->size || bytes < nvmem->word_size)
>>> +        return 0;
>>> +
>>> +    if (bytes + offset > nvmem->size)
>>> +        bytes = nvmem->size - offset;
>>
>> The check is relevant for nvmem_device_write(), too.
>>
>> There are also other ways to access nvmem devices such as nvmem_cell_read
>> and others alike. Should they be considered as well?
> 
> We should probably move these sanity checks to a common place like
> nvmem_reg_read() and nvmem_reg_write(), so the callers need not duplicate the same!
> 
Srini and Sakari, thanks for your review.

Is it OK just return INVAL with simple check like below?

if (bytes + offset > nvmem->size ||
    bytes != round_down(bytes, nvmem->word_size))
        return -EINVAL;


> --srini
> 
>>
>>> +
>>> +    bytes = round_down(bytes, nvmem->word_size);
>>>       rc = nvmem_reg_read(nvmem, offset, buf, bytes);
>>>         if (rc)
>>

-- 
Best regards,
Bingbu Cao

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] nvmem: core: add sanity check in nvmem_device_read()
  2020-08-04 10:44     ` Bingbu Cao
@ 2020-08-04 10:56       ` Sakari Ailus
  0 siblings, 0 replies; 5+ messages in thread
From: Sakari Ailus @ 2020-08-04 10:56 UTC (permalink / raw)
  To: Bingbu Cao; +Cc: Srinivas Kandagatla, Bingbu Cao, linux-kernel

On Tue, Aug 04, 2020 at 06:44:27PM +0800, Bingbu Cao wrote:
> 
> On 8/4/20 6:03 PM, Srinivas Kandagatla wrote:
> > 
> > 
> > On 04/08/2020 10:58, Sakari Ailus wrote:
> >> Hi Bingbu,
> >>
> >> Thank you for the patch.
> >>
> >> On Tue, Aug 04, 2020 at 05:13:56PM +0800, Bingbu Cao wrote:
> >>> nvmem_device_read() could be called directly once nvmem device
> >>> registered, the sanity check should be done before call
> >>> nvmem_reg_read() as cell and sysfs read did now.
> >>>
> >>> Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
> >>> ---
> >>>   drivers/nvmem/core.c | 7 +++++++
> >>>   1 file changed, 7 insertions(+)
> >>>
> >>> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> >>> index 927eb5f6003f..c9a77993f008 100644
> >>> --- a/drivers/nvmem/core.c
> >>> +++ b/drivers/nvmem/core.c
> >>> @@ -1491,6 +1491,13 @@ int nvmem_device_read(struct nvmem_device *nvmem,
> >>>       if (!nvmem)
> >>>           return -EINVAL;
> >>>   +    if (offset >= nvmem->size || bytes < nvmem->word_size)
> >>> +        return 0;
> >>> +
> >>> +    if (bytes + offset > nvmem->size)
> >>> +        bytes = nvmem->size - offset;
> >>
> >> The check is relevant for nvmem_device_write(), too.
> >>
> >> There are also other ways to access nvmem devices such as nvmem_cell_read
> >> and others alike. Should they be considered as well?
> > 
> > We should probably move these sanity checks to a common place like
> > nvmem_reg_read() and nvmem_reg_write(), so the callers need not duplicate the same!
> > 
> Srini and Sakari, thanks for your review.
> 
> Is it OK just return INVAL with simple check like below?
> 
> if (bytes + offset > nvmem->size ||
>     bytes != round_down(bytes, nvmem->word_size))
>         return -EINVAL;

This changes what is currently supported so I'd say no.

-- 
Sakari Ailus

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-08-04 10:56 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-04  9:13 [PATCH] nvmem: core: add sanity check in nvmem_device_read() Bingbu Cao
2020-08-04  9:58 ` Sakari Ailus
2020-08-04 10:03   ` Srinivas Kandagatla
2020-08-04 10:44     ` Bingbu Cao
2020-08-04 10:56       ` Sakari Ailus

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