Re: [dpdk-dev] [dpdk-stable] [PATCH] net/mlx5: fix: flow validation

[Shahaf Shuler <shahafs@mellanox.com>]

Hi Nelio,

Wednesday, May 2, 2018 5:43 PM, Nelio Laranjeiro:
> Subject: [dpdk-stable] [PATCH] net/mlx5: fix: flow validation

The title is wrong the : after the fix should be removed. 

> 
> Item spec and last are wrongly compared to the NIC capability causing a
> validation failure when the mask is null.
> This validation function should only verify the user is not configuring
> unsupported matching fields.
> 
> Fixes: 2097d0d1e2cc ("net/mlx5: support basic flow items and actions")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
> ---
>  drivers/net/mlx5/mlx5_flow.c | 73 +++++++++++-------------------------
>  1 file changed, 22 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
> index 129311d50..5d4995783 100644
> --- a/drivers/net/mlx5/mlx5_flow.c
> +++ b/drivers/net/mlx5/mlx5_flow.c
> @@ -555,60 +555,31 @@ static int
>  mlx5_flow_item_validate(const struct rte_flow_item *item,
>  			const uint8_t *mask, unsigned int size)  {
> -	if (!item->spec && (item->mask || item->last)) {
> -		rte_errno = EINVAL;
> -		return -rte_errno;
> -	}
> -	if (item->spec && !item->mask) {
> -		unsigned int i;
> -		const uint8_t *spec = item->spec;
> -
> -		for (i = 0; i < size; ++i)
> -			if ((spec[i] | mask[i]) != mask[i]) {
> -				rte_errno = EINVAL;
> -				return -rte_errno;
> -			}
> -	}
> -	if (item->last && !item->mask) {
> -		unsigned int i;
> -		const uint8_t *spec = item->last;
> -
> -		for (i = 0; i < size; ++i)
> -			if ((spec[i] | mask[i]) != mask[i]) {
> -				rte_errno = EINVAL;
> -				return -rte_errno;
> -			}
> -	}
> -	if (item->mask) {
> -		unsigned int i;
> -		const uint8_t *spec = item->spec;
> -
> -		for (i = 0; i < size; ++i)
> -			if ((spec[i] | mask[i]) != mask[i]) {
> -				rte_errno = EINVAL;
> -				return -rte_errno;
> -			}
> -	}
> -	if (item->spec && item->last) {
> -		uint8_t spec[size];
> -		uint8_t last[size];
> -		const uint8_t *apply = mask;
> -		unsigned int i;
> -		int ret;
> +	unsigned int i;
> +	const uint8_t *spec = item->spec;
> +	const uint8_t *last = item->last;
> +	const uint8_t *m = item->mask ? item->mask : mask;
> 
> -		if (item->mask)
> -			apply = item->mask;
> -		for (i = 0; i < size; ++i) {
> -			spec[i] = ((const uint8_t *)item->spec)[i] & apply[i];
> -			last[i] = ((const uint8_t *)item->last)[i] & apply[i];
> -		}
> -		ret = memcmp(spec, last, size);
> -		if (ret != 0) {
> -			rte_errno = EINVAL;
> -			return -rte_errno;
> -		}
> +	if (!spec && (item->mask || last))
> +		goto error;
> +	if (!spec)
> +		return 0;
> +	for (i = 0; i < size; i++) {


I think inline comment which explains what each code section below verifies would much help.

> +		if (spec)
> +			if (((spec[i] & m[i]) | mask[i]) != mask[i])
> +				goto error;

Am wondering. 
Which the below check of m ...

> +		if (last)
> +			if ((((last[i] & m[i]) | mask[i]) != mask[i]) ||
> +			    ((spec[i] & m[i]) != (last[i] & m[i])))
> +				goto error;
> +		if (m)
> +			if ((m[i] | mask[i]) != mask[i])
> +				goto error;

Do we really need to spec check? 
Meaning if above one passes it is guarantee m is contained in mask. And if so, then the spec check will always succeed. 


>  	}
>  	return 0;
> +error:
> +	rte_errno = ENOTSUP;
> +	return -rte_errno;
>  }
> 
>  /**
> --
> 2.17.0