linux-kernel - Re: [PATCH v3] soc: qcom: cmd-db: replace strscpy

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Message-ID: <c70e269d-4481-5d01-5db9-268e967c90e0@linaro.org>
Date:   Tue, 28 Jun 2022 15:44:19 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Douglas Anderson <dianders@...omium.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Matthias Kaehlcke <mka@...omium.org>,
        Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Stephen Boyd <sboyd@...nel.org>, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] soc: qcom: cmd-db: replace strscpy_pad() with
 strncpy()

On 28/06/2022 15:43, Douglas Anderson wrote:
> Commit ac0126a01735 ("soc: qcom: cmd-db: replace strncpy() with
> strscpy_pad()") breaks booting on my sc7280-herobrine-herobrine
> device. From printouts I see that at bootup the function is called
> with an id of "lnbclka2" which is 8 bytes big.
> 
> Previously all 8 bytes of this string were copied to the
> destination. Now only 7 bytes will be copied since strscpy_pad() saves
> a byte for '\0' termination.
> 
> We don't need the '\0' termination in the destination. Let's go back
> to strncpy(). According to the warning:
>   If a caller is using non-NUL-terminated strings, strncpy() can still
>   be used, but destinations should be marked with the __nonstring
>   attribute to avoid future compiler warnings.
> ...so we'll do that.
> 
> While we're at it, let's change the query array to use
> "sizeof(ent->id)" so it can't possibly go out of sync with our later
> copy.
> 
> Fixes: ac0126a01735 ("soc: qcom: cmd-db: replace strncpy() with strscpy_pad()")
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
> ---
> 
> Changes in v3:
> - Add comment that query isn't necessarily '\0' terminated.
> 

Thanks!

Best regards,
Krzysztof