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To: David Hunt <david.hunt@intel.com>, dev@dpdk.org
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From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
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Date: Fri, 26 Apr 2019 11:33:42 +0100
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Subject: Re: [dpdk-dev] [PATCH v1] examples/vm_power_manager: fix string
 null termination
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On 26-Apr-19 9:43 AM, David Hunt wrote:
> coverity complains about a null-termination after a read,
> so we terminate conditionally on whether idx is within
> the buffer or at the end of the buffer.
> 
> Coverity issue: 337680
> Fixes: a63504a90f ("examples/power: add JSON string handling")
> CC: stable@dpdk.org
> Signed-off-by: David Hunt <david.hunt@intel.com>
> ---
>   examples/vm_power_manager/channel_monitor.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/examples/vm_power_manager/channel_monitor.c b/examples/vm_power_manager/channel_monitor.c
> index 971e4f2bc..711722fef 100644
> --- a/examples/vm_power_manager/channel_monitor.c
> +++ b/examples/vm_power_manager/channel_monitor.c
> @@ -808,6 +808,7 @@ read_json_packet(struct channel_info *chan_info)
>   		int indent = 0;
>   		do {
>   			n_bytes = read(chan_info->fd, &json_data[idx], 1);
> +			json_data[idx + (idx < MAX_JSON_STRING_LEN - 1)] = '\0';

Why do it inside the loop and not after?

>   			if (n_bytes == 0)
>   				break;
>   			if (json_data[idx] == '{')
> 


-- 
Thanks,
Anatoly