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* [PATCH][net-next] net/mlx4: Use array_size() helper in copy_to_user()
@ 2021-09-28 20:17 Gustavo A. R. Silva
  2021-09-29 10:24 ` Tariq Toukan
  0 siblings, 1 reply; 4+ messages in thread
From: Gustavo A. R. Silva @ 2021-09-28 20:17 UTC (permalink / raw)
  To: Tariq Toukan, David S. Miller, Jakub Kicinski
  Cc: netdev, linux-rdma, linux-kernel, Gustavo A. R. Silva, linux-hardening

Use array_size() helper instead of the open-coded version in
copy_to_user(). These sorts of multiplication factors need
to be wrapped in array_size().

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/net/ethernet/mellanox/mlx4/cq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/cq.c b/drivers/net/ethernet/mellanox/mlx4/cq.c
index f7053a74e6a8..4d4f9cf9facb 100644
--- a/drivers/net/ethernet/mellanox/mlx4/cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/cq.c
@@ -314,7 +314,8 @@ static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
 			buf += PAGE_SIZE;
 		}
 	} else {
-		err = copy_to_user((void __user *)buf, init_ents, entries * cqe_size) ?
+		err = copy_to_user((void __user *)buf, init_ents,
+				   array_size(entries, cqe_size)) ?
 			-EFAULT : 0;
 	}
 
-- 
2.27.0


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

* Re: [PATCH][net-next] net/mlx4: Use array_size() helper in copy_to_user()
  2021-09-28 20:17 [PATCH][net-next] net/mlx4: Use array_size() helper in copy_to_user() Gustavo A. R. Silva
@ 2021-09-29 10:24 ` Tariq Toukan
  2021-09-29 17:21   ` Eric Dumazet
  0 siblings, 1 reply; 4+ messages in thread
From: Tariq Toukan @ 2021-09-29 10:24 UTC (permalink / raw)
  To: Gustavo A. R. Silva, Tariq Toukan, David S. Miller, Jakub Kicinski
  Cc: netdev, linux-rdma, linux-kernel, linux-hardening



On 9/28/2021 11:17 PM, Gustavo A. R. Silva wrote:
> Use array_size() helper instead of the open-coded version in
> copy_to_user(). These sorts of multiplication factors need
> to be wrapped in array_size().
> 
> Link: https://github.com/KSPP/linux/issues/160
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>   drivers/net/ethernet/mellanox/mlx4/cq.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/cq.c b/drivers/net/ethernet/mellanox/mlx4/cq.c
> index f7053a74e6a8..4d4f9cf9facb 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/cq.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/cq.c
> @@ -314,7 +314,8 @@ static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
>   			buf += PAGE_SIZE;
>   		}
>   	} else {
> -		err = copy_to_user((void __user *)buf, init_ents, entries * cqe_size) ?
> +		err = copy_to_user((void __user *)buf, init_ents,
> +				   array_size(entries, cqe_size)) ?
>   			-EFAULT : 0;
>   	}
>   
> 

Thanks for your patch.
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>

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

* Re: [PATCH][net-next] net/mlx4: Use array_size() helper in copy_to_user()
  2021-09-29 10:24 ` Tariq Toukan
@ 2021-09-29 17:21   ` Eric Dumazet
  2021-09-29 17:45     ` Tariq Toukan
  0 siblings, 1 reply; 4+ messages in thread
From: Eric Dumazet @ 2021-09-29 17:21 UTC (permalink / raw)
  To: Tariq Toukan, Gustavo A. R. Silva, Tariq Toukan, David S. Miller,
	Jakub Kicinski
  Cc: netdev, linux-rdma, linux-kernel, linux-hardening



On 9/29/21 3:24 AM, Tariq Toukan wrote:
> 
> 
> On 9/28/2021 11:17 PM, Gustavo A. R. Silva wrote:
>> Use array_size() helper instead of the open-coded version in
>> copy_to_user(). These sorts of multiplication factors need
>> to be wrapped in array_size().
>>
>> Link: https://github.com/KSPP/linux/issues/160
>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>> ---
>>   drivers/net/ethernet/mellanox/mlx4/cq.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx4/cq.c b/drivers/net/ethernet/mellanox/mlx4/cq.c
>> index f7053a74e6a8..4d4f9cf9facb 100644
>> --- a/drivers/net/ethernet/mellanox/mlx4/cq.c
>> +++ b/drivers/net/ethernet/mellanox/mlx4/cq.c
>> @@ -314,7 +314,8 @@ static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
>>               buf += PAGE_SIZE;
>>           }
>>       } else {
>> -        err = copy_to_user((void __user *)buf, init_ents, entries * cqe_size) ?
>> +        err = copy_to_user((void __user *)buf, init_ents,
>> +                   array_size(entries, cqe_size)) ?
>>               -EFAULT : 0;
>>       }
>>  
> 
> Thanks for your patch.
> Reviewed-by: Tariq Toukan <tariqt@nvidia.com>

Not sure why avoiding size_t overflows would make this code safer.
init_ents contains PAGE_SIZE bytes...

BTW

Is @entries guaranteed to be a power of two ?

This function seems to either copy one chunk ( <= PAGE_SIZE),
or a number of full pages.


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

* Re: [PATCH][net-next] net/mlx4: Use array_size() helper in copy_to_user()
  2021-09-29 17:21   ` Eric Dumazet
@ 2021-09-29 17:45     ` Tariq Toukan
  0 siblings, 0 replies; 4+ messages in thread
From: Tariq Toukan @ 2021-09-29 17:45 UTC (permalink / raw)
  To: Eric Dumazet, Gustavo A. R. Silva, Tariq Toukan, David S. Miller,
	Jakub Kicinski
  Cc: netdev, linux-rdma, linux-kernel, linux-hardening



On 9/29/2021 8:21 PM, Eric Dumazet wrote:
> 
> 
> On 9/29/21 3:24 AM, Tariq Toukan wrote:
>>
>>
>> On 9/28/2021 11:17 PM, Gustavo A. R. Silva wrote:
>>> Use array_size() helper instead of the open-coded version in
>>> copy_to_user(). These sorts of multiplication factors need
>>> to be wrapped in array_size().
>>>
>>> Link: https://github.com/KSPP/linux/issues/160
>>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>>> ---
>>>    drivers/net/ethernet/mellanox/mlx4/cq.c | 3 ++-
>>>    1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ethernet/mellanox/mlx4/cq.c b/drivers/net/ethernet/mellanox/mlx4/cq.c
>>> index f7053a74e6a8..4d4f9cf9facb 100644
>>> --- a/drivers/net/ethernet/mellanox/mlx4/cq.c
>>> +++ b/drivers/net/ethernet/mellanox/mlx4/cq.c
>>> @@ -314,7 +314,8 @@ static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
>>>                buf += PAGE_SIZE;
>>>            }
>>>        } else {
>>> -        err = copy_to_user((void __user *)buf, init_ents, entries * cqe_size) ?
>>> +        err = copy_to_user((void __user *)buf, init_ents,
>>> +                   array_size(entries, cqe_size)) ?
>>>                -EFAULT : 0;
>>>        }
>>>   
>>
>> Thanks for your patch.
>> Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
> 
> Not sure why avoiding size_t overflows would make this code safer.
> init_ents contains PAGE_SIZE bytes...
> 
> BTW
> 
> Is @entries guaranteed to be a power of two ?

Yes.

> 
> This function seems to either copy one chunk ( <= PAGE_SIZE),
> or a number of full pages.
> 

Exactly. No remainder handling is needed, for the reason you mentioned 
above.

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

end of thread, other threads:[~2021-09-29 17:45 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-09-28 20:17 [PATCH][net-next] net/mlx4: Use array_size() helper in copy_to_user() Gustavo A. R. Silva
2021-09-29 10:24 ` Tariq Toukan
2021-09-29 17:21   ` Eric Dumazet
2021-09-29 17:45     ` Tariq Toukan

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