[U-Boot] [PATCH] rsa: read out public_exponent value based on 32-bit alignment

[Ooi, Joyce]

Hi Marek,

Any comments about this?

Thanks,
Joyce Ooi

> -----Original Message-----
> From: Ooi, Joyce
> Sent: Saturday, December 8, 2018 4:18 PM
> To: Marek Vasut <marex at denx.de>; Michal Simek <michal.simek at xilinx.com>;
> Siva Durga Prasad Paladugu <siva.durga.paladugu at xilinx.com>
> Cc: u-boot at lists.denx.de; Ooi, Joyce <joyce.ooi at intel.com>; See, Chin Liang
> <chin.liang.see at intel.com>; Chee, Tien Fong <tien.fong.chee at intel.com>; Tan,
> Ley Foon <ley.foon.tan at intel.com>
> Subject: [PATCH] rsa: read out public_exponent value based on 32-bit alignment
> 
> Public_exponent is a 64-bit data, which is stored in the device tree blob in a 32-
> bit alignment address. This causes a problem for ARM64 when public_exponent
> is read out one shot as a 64-bit data from an unaligned address. Hence, to solve
> this problem, public_exponent is read out as two 32-bit datas, and then
> concatenating them.
> 
> Signed-off-by: Ooi, Joyce <joyce.ooi at intel.com>
> ---
>  lib/rsa/rsa-mod-exp.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/rsa/rsa-mod-exp.c b/lib/rsa/rsa-mod-exp.c index
> 9d78aa1..3eace38 100644
> --- a/lib/rsa/rsa-mod-exp.c
> +++ b/lib/rsa/rsa-mod-exp.c
> @@ -252,6 +252,9 @@ int rsa_mod_exp_sw(const uint8_t *sig, uint32_t
> sig_len,  {
>  	struct rsa_public_key key;
>  	int ret;
> +	uint64_t exponent =
> +		(uint64_t)(*((uint32_t *)(prop->public_exponent + 4))) << 32 |
> +		*((uint32_t *)(prop->public_exponent));
> 
>  	if (!prop) {
>  		debug("%s: Skipping invalid prop", __func__); @@ -263,8
> +266,7 @@ int rsa_mod_exp_sw(const uint8_t *sig, uint32_t sig_len,
>  	if (!prop->public_exponent)
>  		key.exponent = RSA_DEFAULT_PUBEXP;
>  	else
> -		key.exponent =
> -			fdt64_to_cpu(*((uint64_t *)(prop->public_exponent)));
> +		key.exponent = fdt64_to_cpu(exponent);
> 
>  	if (!key.len || !prop->modulus || !prop->rr) {
>  		debug("%s: Missing RSA key info", __func__);
> --
> 1.7.1