Re: [PATCH] dma-buf: Replace strlcpy() with strscpy()

[T.J. Mercier]

On Thu, Nov 16, 2023 at 11:14 AM Kees Cook <keescook@xxxxxxxxxxxx> 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].
> Additionally, it returns the size of the source string, not the
> resulting size of the destination string. In an effort to remove strlcpy()
> completely[2], replace strlcpy() here with strscpy().
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [1]
> Link: https://github.com/KSPP/linux/issues/89 [2]
> Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
> Cc: "Christian König" <christian.koenig@xxxxxxx>
> Cc: Azeem Shaikh <azeemshaikh38@xxxxxxxxx>
> Cc: linux-media@xxxxxxxxxxxxxxx
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: linaro-mm-sig@xxxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Reviewed-by: T.J. Mercier <tjmercier@xxxxxxxxxx>

strscpy returns -E2BIG when it truncates / force null-terminates which
would provide the wrong argument for dynamic_dname, but
dma_buf_set_name{_user} makes sure we have a null-terminated string of
the appropriate maximum size in dmabuf->name.