Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] crypto: hisilicon - fix strncpy warning with strlcpy
To:     Herbert Xu <herbert@gondor.apana.org.au>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        wangzhou1 <wangzhou1@hisilicon.com>,
        linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
        kbuild-all@lists.01.org
References: <202006032110.BEbKqovX%lkp@intel.com>
 <1591241524-6452-1-git-send-email-zhangfei.gao@linaro.org>
 <20200604033918.GA2286@gondor.apana.org.au>
 <b6ad8af2-1cb7-faac-0446-5e09e97f3616@linaro.org>
 <20200604061811.GA28759@gondor.apana.org.au>
From:   Zhangfei Gao <zhangfei.gao@linaro.org>
Message-ID: <b23433f8-d95d-8142-c830-fb92e5ccd4a1@linaro.org>
Date:   Thu, 4 Jun 2020 14:44:16 +0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.7.0
MIME-Version: 1.0
In-Reply-To: <20200604061811.GA28759@gondor.apana.org.au>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: en-US
Sender: linux-crypto-owner@vger.kernel.org
Precedence: bulk


On 2020/6/4 下午2:18, Herbert Xu wrote:
> On Thu, Jun 04, 2020 at 02:10:37PM +0800, Zhangfei Gao wrote:
>>> Should this even allow truncation? Perhaps it'd be better to fail
>>> in case of an overrun?
>> I think we do not need consider overrun, since it at most copy size-1 bytes
>> to dest.
>>  From the manual: strlcpy()
>>         This  function  is  similar  to  strncpy(), but it copies at most
>> size-1 bytes to dest, always adds a terminating null
>>         byte,
>> And simple tested with smaller SIZE of interface.name,  only SIZE-1 is
>> copied, so it is safe.
>> -#define UACCE_MAX_NAME_SIZE    64
>> +#define UACCE_MAX_NAME_SIZE    4
> That's not what I meant.  As it is if you do exceed the limit the
> name is silently truncated.  Wouldn't it be better to fail the
> allocation instead?
I think it is fine.
1. Currently the name size is 64, bigger enough.
Simply grep in driver name, 64 should be enough.
We can make it larger when there is a request.
2. it does not matter what the name is, since it is just an interface.
cat /sys/class/uacce/hisi_zip-0/flags
cat /sys/class/uacce/his-0/flags
should be both fine to app only they can be distinguished.
3. It maybe a hard restriction to fail just because of a long name.

What do you think.

Thanks