Am Freitag, 24. März 2017, 19:26:04 CET schrieb Krzysztof Kozlowski:
Hi Krzysztof,
> +static unsigned int exynos_rng_copy_random(struct exynos_rng_dev *rng,
> + u8 *dst, unsigned int dlen)
> +{
> + unsigned int cnt = 0;
> + int i, j;
> + u32 val;
> +
> + for (j = 0; j < EXYNOS_RNG_SEED_REGS; j++) {
> + val = exynos_rng_readl(rng, EXYNOS_RNG_OUT(j));
> +
> + for (i = 0; i < 4; i++) {
> + dst[cnt] = val & 0xff;
> + val >>= 8;
> + if (++cnt >= dlen)
> + return cnt;
> + }
> + rng->seed_save[j] = val;
Just to clarify: is this call right? Shouldn't that be removed? Any RNG that
is given to a caller is tainted and should not serve as seed.
> + }
> +
> + /*
> + * Engine filled all output registers, so read the remaining registers
> + * for storing data as future seed.
> + */
> + for (; j < EXYNOS_RNG_SEED_REGS; j++)
> + rng->seed_save[j] = exynos_rng_readl(rng, EXYNOS_RNG_OUT(j));
With this call, I guess the questioned line above could go away, right?
Ciao
Stephan
