[PATCH v2 2/2] net: Use NDRNG device in srand_mac()

[Simon Glass]

Hi Mattias,

On Wed, 16 Dec 2020 at 09:28, <matthias.bgg at kernel.org> wrote:
>
> From: Matthias Brugger <mbrugger at suse.com>
>
> When calling srand_mac we use a weak seed dependent on the
> mac address. If present, use a RNG device instead to incerase entropy.
>
> Signed-off-by: Matthias Brugger <mbrugger at suse.com>
>
> ---
>
> Changes in v2:
> - fix dm_rng_read() parameters
> - add missing include file
>
>  net/net_rand.h | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/net/net_rand.h b/net/net_rand.h
> index 4bf9bd817e..e7299973a3 100644
> --- a/net/net_rand.h
> +++ b/net/net_rand.h
> @@ -10,6 +10,8 @@
>  #define __NET_RAND_H__
>
>  #include <common.h>
> +#include <dm/uclass.h>
> +#include <rng.h>
>
>  /*
>   * Return a seed for the PRNG derived from the eth0 MAC address.
> @@ -37,7 +39,22 @@ static inline unsigned int seed_mac(void)
>   */
>  static inline void srand_mac(void)
>  {
> -       srand(seed_mac());
> +#if defined(CONFIG_DM_RNG)

if (IS_ENABLED())

Similar comment to the other patch


> +       int ret;
> +       struct udevice *devp;
> +       u32 randv = 0;
> +
> +       ret = uclass_get_device(UCLASS_RNG, 0, &devp);
> +       if (ret) {
> +               ret = dm_rng_read(devp, &randv, sizeof(randv));
> +               if (ret < 0)
> +                       randv = 0;
> +       }
> +       if (randv)
> +               srand(randv);
> +       else
> +#endif
> +               srand(seed_mac());
>  }
>
>  #endif /* __NET_RAND_H__ */
> --
> 2.29.2
>