Re: [dpdk-dev] [PATCH] net/ring: fix unchecked return value

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 10/1/2020 3:14 PM, Kevin Laatz wrote:
> 
> On 25/09/2020 13:43, Ferruh Yigit wrote:
>> On 9/22/2020 6:20 PM, Kevin Laatz wrote:
>>> Add a check for the return value of the sscanf call in
>>> parse_internal_args(), returning an error if we don't get the expected
>>> result.
>>>
>>> Coverity issue: 362049
>>> Fixes: 96cb19521147 ("net/ring: use EAL APIs in PMD specific API")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>
>>> ---
>>>   drivers/net/ring/rte_eth_ring.c | 3 ++-
>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ring/rte_eth_ring.c b/drivers/net/ring/rte_eth_ring.c
>>> index 40fe1ca4ba..62060e46ce 100644
>>> --- a/drivers/net/ring/rte_eth_ring.c
>>> +++ b/drivers/net/ring/rte_eth_ring.c
>>> @@ -539,7 +539,8 @@ parse_internal_args(const char *key __rte_unused, const 
>>> char *value,
>>>       struct ring_internal_args **internal_args = data;
>>>       void *args;
>>>   -    sscanf(value, "%p", &args);
>>> +    if (sscanf(value, "%p", &args) != 1)
>>> +        return -1;
>>
>> I am aware that this is just to fix the coverity error to check the return 
>> value, BUT :)
>>
>> The internal args is mainly to pass the information get by API 
>> ('rte_eth_from_ring()') to ring probe. And the main information to pass is the 
>> ring.
>> It may be possible to pass the ring_name only and eliminate internal args 
>> completely, the driver already has a way to pass ring name:
>> "nodeaction=name:node:ATTACH" devargs.
>>
>> If you have time, can you please check if it can be possible to fill and pass 
>> the nodeaction devargs in 'rte_eth_from_rings()' and eliminate the 'internal' 
>> devargs completely?
>> If it works, as a bonus it will resolve above coverity issue by removing it :)
>>
> Hi Ferruh,
> 
> It seems to be used for more than just that - after the parsing, the internal 
> args are passed to do_eth_dev_ring_create() as multiple parameters.
> 

Yes multiple args passed to 'do_eth_dev_ring_create()' from internal arg, and 
they may be provided via existing nodeaction arg too, needs to be checked.

Anyway, the option to eliminate the internal args is just a good to have, we can 
check it later instead making the this coverity fix more complex.