[PATCH V2] mkimage: fit: Do not tail-pad fitImage with external data

[Simon Glass <sjg@chromium.org>]

On Fri, 1 May 2020 at 09:40, Marek Vasut <marex@denx.de> wrote:
>
> There is no reason to tail-pad fitImage with external data to 4-bytes,
> while fitImage without external data does not have any such padding and
> is often unaligned. DT spec also does not mandate any such padding.
>
> Moreover, the tail-pad fills the last few bytes with uninitialized data,
> which could lead to a potential information leak.
>
> $ echo -n xy > /tmp/data ; \
>         ./tools/mkimage -E -f auto -d /tmp/data /tmp/fitImage ; \
>         hexdump -vC /tmp/fitImage | tail -n 3
>
> before:
> 00000260  61 2d 6f 66 66 73 65 74  00 64 61 74 61 2d 73 69  |a-offset.data-si|
> 00000270  7a 65 00 00 78 79 64 64                           |ze..xydd|
>                    ^^       ^^ ^^
> after:
> 00000260  61 2d 6f 66 66 73 65 74  00 64 61 74 61 2d 73 69  |a-offset.data-si|
> 00000270  7a 65 00 78 79                                    |ze.xy|
>
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
> Cc: Simon Glass <sjg@chromium.org>
> Cc: Tom Rini <trini@konsulko.com>
> ---
> V2: Rebase on u-boot/master, update commit message
> ---
>  tools/fit_image.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)

Reviewed-by: Simon Glass <sjg@chromium.org>