Re: [PATCH V4 net-next 7/8] net: hns3: Add Ethtool support to HNS3 driver

[Rustad, Mark D]

> On Jul 23, 2017, at 10:05 AM, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote:
>> +
>> +	strncpy(drvinfo->version, HNAE_DRIVER_VERSION,
>> +		sizeof(drvinfo->version));
>> +	drvinfo->version[sizeof(drvinfo->version) - 1] = '\0';
> 
> strlcpy() would probably do that for you.

You need to be careful about strlcpy - it does not completely write the destination buffer as strncpy does, and so can result in a kernel memory leak if the destination is not known to already be cleared.

>> +
>> +	strncpy(drvinfo->driver, HNAE_DRIVER_NAME, sizeof(drvinfo->driver));
>> +	drvinfo->driver[sizeof(drvinfo->driver) - 1] = '\0';
> 
> Same here

Same here

>> +
>> +	strncpy(drvinfo->bus_info, priv->dev->bus->name,
>> +		sizeof(drvinfo->bus_info));> +	drvinfo->bus_info[ETHTOOL_BUSINFO_LEN - 1] = '\0';
> 
> And here.

And here too. I haven't looked at this deeply enough to know whether a leak could be created by strlcpy here, but I wanted to raise it as something to be considered before switching to it. Blindly adopting strlcpy is hazardous as are tools that unconditionally recommend it.

--
Mark Rustad, Networking Division, Intel Corporation

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