[PATCH 1/1] lib: rsa: fix data abort in br_i32_decode()

[Simon Glass]

HI Heinrich,

On Tue, 8 Sep 2020 at 04:29, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> After removing leading zeros the RSA modulus may be unaligned. On
> architectures like ARM 32bit unaligned access may lead to a data abort,
> e.g. when executing 'ut lib lib_asn1_pkcs7'.
>
> Use memcpy() to transfer from unaligned to aligned memory.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
>  lib/rsa/rsa-keyprop.c | 22 ++++++++++++++--------
>  1 file changed, 14 insertions(+), 8 deletions(-)

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

>
> diff --git a/lib/rsa/rsa-keyprop.c b/lib/rsa/rsa-keyprop.c
> index 1e83eedc82..6153cb00b3 100644
> --- a/lib/rsa/rsa-keyprop.c
> +++ b/lib/rsa/rsa-keyprop.c
> @@ -17,23 +17,29 @@
>  #include <u-boot/rsa-mod-exp.h>
>
>  /**
> - * br_dec16be() - Convert 16-bit big-endian integer to native
> - * @src:       Pointer to data
> - * Return:     Native-endian integer
> + * br_dec16be() - convert unaligned 16-bit big-endian integer to native
> + * @src:       unaligned pointer to data
> + * Return:     native-endian 16-bit integer
>   */
>  static unsigned br_dec16be(const void *src)
>  {
> -       return be16_to_cpup(src);
> +       u16 buf;
> +
> +       memcpy(&buf, src, sizeof(buf));
> +       return be16_to_cpu(buf);

Is it possible to use __get_unaligned_be() ?

Regards,
Simon