Re: [dpdk-dev] [dpdk-stable] [PATCH] eal: fix dereference before null check

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 9/19/2020 11:34 AM, wangyunjian wrote:
> From: Yunjian Wang <wangyunjian@huawei.com>
> 
> This patch fixes (dereference after null check) coverity issue.
> The intr_handle may be a null pointer which led to this issue.
> 
> Coverity issue: 357695, 357751
> Fixes: 05c4105738d8 ("trace: add interrupt tracepoints")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> ---
>   lib/librte_eal/freebsd/eal_interrupts.c | 6 ++++--
>   lib/librte_eal/linux/eal_interrupts.c   | 6 ++++--
>   2 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/librte_eal/freebsd/eal_interrupts.c b/lib/librte_eal/freebsd/eal_interrupts.c
> index 6d53d33c8..028ab457a 100644
> --- a/lib/librte_eal/freebsd/eal_interrupts.c
> +++ b/lib/librte_eal/freebsd/eal_interrupts.c
> @@ -380,7 +380,8 @@ rte_intr_enable(const struct rte_intr_handle *intr_handle)
>   	}
>   
>   out:
> -	rte_eal_trace_intr_enable(intr_handle, rc);
> +	if (intr_handle)
> +		rte_eal_trace_intr_enable(intr_handle, rc);
>   	return rc;
>   }
>   
> @@ -418,7 +419,8 @@ rte_intr_disable(const struct rte_intr_handle *intr_handle)
>   		break;
>   	}
>   out:
> -	rte_eal_trace_intr_disable(intr_handle, rc);
> +	if (intr_handle)
> +		rte_eal_trace_intr_disable(intr_handle, rc);
>   	return rc;
>   }
>   
> diff --git a/lib/librte_eal/linux/eal_interrupts.c b/lib/librte_eal/linux/eal_interrupts.c
> index 13db5c4e8..e46443873 100644
> --- a/lib/librte_eal/linux/eal_interrupts.c
> +++ b/lib/librte_eal/linux/eal_interrupts.c
> @@ -725,7 +725,8 @@ rte_intr_enable(const struct rte_intr_handle *intr_handle)
>   		break;
>   	}
>   out:
> -	rte_eal_trace_intr_enable(intr_handle, rc);
> +	if (intr_handle)
> +		rte_eal_trace_intr_enable(intr_handle, rc);
>   	return rc;

It looks like whole function requires 'intr_handle' to be not NULL, so what do 
you think add following at the very beginning of the function and remove other 
'intr_handle' NULL checks from function:

if (intr_handle == NULL)
	return -1;

>   }
>   
> @@ -852,7 +853,8 @@ rte_intr_disable(const struct rte_intr_handle *intr_handle)
>   		break;
>   	}
>   out:
> -	rte_eal_trace_intr_disable(intr_handle, rc);
> +	if (intr_handle)
> +		rte_eal_trace_intr_disable(intr_handle, rc);
>   	return rc;
>   }
>   
>