Re: [PATCH v2] crypto: Replace strlcpy with strscpy

From: Kees Cook
Date: Tue Jun 20 2023 - 16:12:16 EST


On Tue, Jun 20, 2023 at 08:08:32PM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
>
> Direct replacement is safe here since return value of -errno
> is used to check for truncation instead of sizeof(dest).
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
>
> Signed-off-by: Azeem Shaikh <azeemshaikh38@xxxxxxxxx>

Thanks for fixing up the variable type. (And thank you Eric for catching
the signedness problem!)

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

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Kees Cook