Re: [dpdk-stable] [PATCH v3] net/failsafe: fix parameters parsing

["Gaëtan Rivet" <gaetan.rivet@6wind.com>]

Hi Matan,

thanks

On Sun, Aug 27, 2017 at 10:23:14AM +0300, Matan Azrad wrote:
> The corrupted code used wrongly snprintf return value as the
> number of characters actually copied, in spite of the meanning
> is the number of characters which would be generated for the
> given input.
> 
> It caused to remain zerod bytes between the failsafe command line
> non sub device parameters indicates end of string.
> 
> Hence, when rte_kvargs_parse tried to parse all parameters, it
> got end of string after the first one and the others weren't parsed.
> 
> So, if the mac parameters was the first in command line it was
> taken while hotplug_poll was left default, and vice versa.
> 
> The fix updates the buffer index by dedicated variable contains
> the copy size, by the way validates the comma separation.
> 
> Fixes: a46f8d584eb8 ("net/failsafe: add fail-safe PMD")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Gaetan Rivet <gaetan.rivet@6wind.com>
> ---
>  drivers/net/failsafe/failsafe_args.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/failsafe/failsafe_args.c b/drivers/net/failsafe/failsafe_args.c
> index 1f22416..ae857b0 100644
> --- a/drivers/net/failsafe/failsafe_args.c
> +++ b/drivers/net/failsafe/failsafe_args.c
> @@ -286,10 +286,17 @@ fs_remove_sub_devices_definition(char params[DEVARGS_MAXLEN])
>  			ERROR("Invalid parameter");
>  			return -EINVAL;
>  		}
> -		if (params[b] == ',' || params[b] == '\0')
> -			i += snprintf(&buffer[i], b - a + 1, "%s", &params[a]);
> -		if (params[b] == '(') {
> +		if (params[b] == ',' || params[b] == '\0') {
> +			size_t len = b - a;
> +
> +			if (i > 0)
> +				len += 1;
> +			snprintf(&buffer[i], len + 1, "%s%s",
> +					i ? "," : "", &params[a]);
> +			i += len;
> +		} else if (params[b] == '(') {
>  			size_t start = b;
> +
>  			b += closing_paren(&params[b]);
>  			if (b == start)
>  				return -EINVAL;
> @@ -393,6 +400,7 @@ failsafe_args_parse(struct rte_eth_dev *dev, const char *params)
>  					&dev->data->mac_addrs[0]);
>  			if (ret < 0)
>  				goto free_kvlist;
> +
>  			mac_from_arg = 1;
>  		}
>  	}
> -- 
> 2.7.4
> 

-- 
Gaëtan Rivet
6WIND