[PATCH v3 1/2] lib: uuid: use RNG device if present

[Patrick DELAUNAY]

Hi

On 12/18/20 10:28 AM, matthias.bgg at kernel.org wrote:
> From: Matthias Brugger <mbrugger at suse.com>
>
> When calculating a random UUID we use a weak seed.
> Use a RNG device if present to increase entropy.
>
> Signed-off-by: Matthias Brugger <mbrugger at suse.com>
>
> ---
>
> Changes in v3:
> - use IS_ENABLED instead of #if
> - use 4 byte for entropy
>
> Changes in v2:
> - fix dm_rng_read() parameters
> - add missing include
>
>   lib/uuid.c | 21 ++++++++++++++++++---
>   1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/lib/uuid.c b/lib/uuid.c
> index e62d5ca264..23af2b4800 100644
> --- a/lib/uuid.c
> +++ b/lib/uuid.c
> @@ -15,6 +15,8 @@
>   #include <asm/io.h>
>   #include <part_efi.h>
>   #include <malloc.h>
> +#include <dm/uclass.h>
> +#include <rng.h>
>   
>   /*
>    * UUID - Universally Unique IDentifier - 128 bits unique number.
> @@ -249,9 +251,22 @@ void gen_rand_uuid(unsigned char *uuid_bin)
>   {
>   	u32 ptr[4];
>   	struct uuid *uuid = (struct uuid *)ptr;
> -	int i;
> -
> -	srand(get_ticks() + rand());
> +	int i, ret;
> +	struct udevice *devp;
> +	u32 randv = 0;
> +
> +	if (IS_ENABLED(CONFIG_DM_RNG)) {
> +		ret = uclass_get_device(UCLASS_RNG, 0, &devp);
> +		if (ret) {

For information, as this patch already merged
here we need to test if ret == 0:

+ if (!ret) {


I push a patch to correct this test:

"lib: uuid: fix the test on RNG device presence"

http://patchwork.ozlabs.org/project/uboot/patch/20211022170544.1.Ib218a8a747f99cab44c3fac6af649f17f003b2e2@changeid/


> +			ret = dm_rng_read(devp, &randv, sizeof(randv));
> +			if (ret < 0)
> +				randv = 0;
> +		}
> +	}
> +	if (randv)
> +		srand(randv);
> +	else
> +		srand(get_ticks() + rand());
>   
>   	/* Set all fields randomly */
>   	for (i = 0; i < 4; i++)

Regards

Patrick