Re: [dpdk-dev] [PATCH v4] eal: out-of-bounds write

[Panu Matilainen <pmatilai@redhat.com>]

On 06/15/2016 04:25 PM, Slawomir Mrozowicz wrote:
> Overrunning array mcfg->memseg of 256 44-byte elements
> at element index 257 using index j.
> Fixed by add condition with message information.
>
> Fixes: af75078fece3 ("first public release")
> Coverity ID 13282
>
> Signed-off-by: Slawomir Mrozowicz <slawomirx.mrozowicz@intel.com>
> ---
>  lib/librte_eal/linuxapp/eal/eal_memory.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
> index 5b9132c..19753b1 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> @@ -1301,6 +1301,15 @@ rte_eal_hugepage_init(void)
>  			break;
>  		}
>
> +	if (j >= RTE_MAX_MEMSEG) {
> +		RTE_LOG(ERR, EAL,
> +			"Failed: all memsegs used by ivshmem.\n"
> +			"Current %d is not enough.\n"
> +			"Please either increase the RTE_MAX_MEMSEG\n",
> +			RTE_MAX_MEMSEG);
> +		return -ENOMEM;
> +	}


The error message is either incomplete or not coherent: "please either 
increase..." or what?

Also no need for that "Failed:" because its already prefixed by 
"Error:". I'm not sure how helpful it is to have an error message 
suggest increasing a value that requires recomplication, but maybe 
something more in the lines of:

("All memory segments exhausted by IVSHMEM. Try recompiling with larger 
RTE_MAX_MEMSEG than current %d?", RTE_MAX_MEMSEG)

	- Panu -