Re: [dpdk-dev] [PATCH 1/2] rte_mempool: fix strncpy warnings

[Olivier Matz <olivier.matz@6wind.com>]

Hi Stephen,

On Mon, Mar 19, 2018 at 10:52:12AM -0700, Stephen Hemminger wrote:
> [dpdk-dev] [PATCH 1/2] rte_mempool: fix strncpy warnings

The title should be prefixed by "mbuf:" instead of "rte_mempool:"

> Gcc-8 discovers issue with platform_mempool_ops.
> rte_mbuf_pool_ops.c:26:3: error: ‘strncpy’ output truncated before
>   terminating nul copying as many bytes from a string as its length
>   [-Werror=stringop-truncation]
>   strncpy(mz->addr, ops_name,  strlen(ops_name));
> 
> The issue is that the size should be size in destination not source.
> 
> Fixes: a3acc3144a76 ("mbuf: add pool ops selection functions")
> ---
>  lib/librte_mbuf/rte_mbuf_pool_ops.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_mbuf/rte_mbuf_pool_ops.c b/lib/librte_mbuf/rte_mbuf_pool_ops.c
> index 48cc342002a5..661cf4fb401f 100644
> --- a/lib/librte_mbuf/rte_mbuf_pool_ops.c
> +++ b/lib/librte_mbuf/rte_mbuf_pool_ops.c
> @@ -23,7 +23,7 @@ rte_mbuf_set_platform_mempool_ops(const char *ops_name)
>  			RTE_MEMPOOL_OPS_NAMESIZE, SOCKET_ID_ANY, 0);
>  		if (mz == NULL)
>  			return -rte_errno;
> -		strncpy(mz->addr, ops_name, strlen(ops_name));
> +		strncpy(mz->addr, ops_name, sizeof(mz->addr) - 1);

sizeof(mz->addr) is the size of the pointer, which is probably not
what you want. It should be RTE_MEMPOOL_OPS_NAMESIZE.


>  		return 0;
>  	} else if (strcmp(mz->addr, ops_name) == 0) {
>  		return 0;
> @@ -62,7 +62,7 @@ rte_mbuf_set_user_mempool_ops(const char *ops_name)
>  			return -rte_errno;
>  	}
>  
> -	strncpy(mz->addr, ops_name, strlen(ops_name));
> +	strncpy(mz->addr, ops_name, sizeof(mz->addr) - 1);
>  	return 0;

Same here.


Olivier