Re: [dpdk-dev] [PATCH] ether: fix invalid string length in ethdev name comparison

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Mohammad Abdul Awal
> Sent: Monday, February 26, 2018 11:22 PM
> To: thomas@monjalon.net
> Cc: rkerur@gmail.com; dev@dpdk.org; Awal, Mohammad Abdul <mohammad.abdul.awal@intel.com>
> Subject: [dpdk-dev] [PATCH] ether: fix invalid string length in ethdev name comparison
> 
> The current code compares two strings upto the length of 1st string
> (searched name). If the 1st string is prefix of 2nd string (existing name),
> the string comparison returns the port_id of earliest prefix matches.
> This patch fixes the bug by comparing the strings upto the length of larger
> string.
> 
> Fixes: 9c5b8d8b9fe ("ethdev: clean port id retrieval when attaching")
> 
> Signed-off-by: Mohammad Abdul Awal <mohammad.abdul.awal@intel.com>
> ---
>  lib/librte_ether/rte_ethdev.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
> index 0590f0c..8e8097b 100644
> --- a/lib/librte_ether/rte_ethdev.c
> +++ b/lib/librte_ether/rte_ethdev.c
> @@ -563,17 +563,20 @@ rte_eth_dev_get_name_by_port(uint16_t port_id, char *name)
>  int
>  rte_eth_dev_get_port_by_name(const char *name, uint16_t *port_id)
>  {
> -	uint32_t pid;
> +	uint32_t pid, len, len1, len2;
> 
>  	if (name == NULL) {
>  		RTE_PMD_DEBUG_TRACE("Null pointer is specified\n");
>  		return -EINVAL;
>  	}
> 
> +	len1 = strlen(name);
>  	for (pid = 0; pid < RTE_MAX_ETHPORTS; pid++) {
> +		len2 = strlen(rte_eth_dev_shared_data->data[pid].name);
> +		len = len1 > len2 ? len1 : len2;
>  		if (rte_eth_devices[pid].state != RTE_ETH_DEV_UNUSED &&
>  		    !strncmp(name, rte_eth_dev_shared_data->data[pid].name,
> -			     strlen(name))) {
> +			     len)) {

Why just not simply use strcmp()? :)

>  			*port_id = pid;
>  			return 0;
>  		}
> --
> 2.7.4