linux-kernel - Re: [PATCH] ARM: s3c: Use strscpy to replace strlcpy

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Message-ID: <6ca0d3e1-b895-e6c8-e075-786f24c19696@canonical.com>
Date:   Mon, 6 Sep 2021 15:57:44 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
To:     Jason Wang <wangborong@...rlc.com>
Cc:     linux@...linux.org.uk, linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: s3c: Use strscpy to replace strlcpy

On 06/09/2021 15:46, Jason Wang wrote:
> The strlcpy should not be used because it doesn't limit the source
> length. As linus says, it's a completely useless function if you
> can't implicitly trust the source string - but that is almost always
> why people think they should use it! All in all the BSD function
> will lead some potential bugs.
> 
> But the strscpy doesn't require reading memory from the src string
> beyond the specified "count" bytes, and since the return value is
> easier to error-check than strlcpy()'s. In addition, the implementation
> is robust to the string changing out from underneath it, unlike the
> current strlcpy() implementation.
> 
> Thus, We prefer using strscpy instead of strlcpy.

Don't copy-paste kernel documentation into commits. It's enough to say
that strlcpy is preferred, according to the kernel coding style (see
strlcpy()).

If you want to add more sentences, make them relevant, e.g. describe
possible effect of bugs depending on the source.




Best regards,
Krzysztof