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Date:   Fri, 5 Jun 2020 08:49:02 -0700
From:   Eric Biggers <ebiggers@kernel.org>
To:     Zhangfei Gao <zhangfei.gao@linaro.org>
Cc:     Herbert Xu <herbert@gondor.apana.org.au>,
        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
Subject: Re: [PATCH] crypto: hisilicon - fix strncpy warning with strlcpy
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On Fri, Jun 05, 2020 at 11:26:20PM +0800, Zhangfei Gao wrote:
> 
> 
> On 2020/6/5 下午8:17, Herbert Xu wrote:
> > On Fri, Jun 05, 2020 at 05:34:32PM +0800, Zhangfei Gao wrote:
> > > Will add a check after the copy.
> > > 
> > >          strlcpy(interface.name, pdev->driver->name, sizeof(interface.name));
> > >          if (strlen(pdev->driver->name) != strlen(interface.name))
> > >                  return -EINVAL;
> > You don't need to do strlen.  The function strlcpy returns the
> > length of the source string.
> > 
> > Better yet use strscpy which will even return an error for you.
> > 
> > 
> Yes, good idea, we can use strscpy.
> 
> +       int ret;
> 
> -       strncpy(interface.name, pdev->driver->name, sizeof(interface.name));
> +       ret = strscpy(interface.name, pdev->driver->name,
> sizeof(interface.name));
> +       if (ret < 0)
> +               return ret;

You might want to use -ENAMETOOLONG instead of the strscpy return value of
-E2BIG.