Missing error check of function entropy_get_entropy()

[Hxinrong]

Hi,
As described in the project API documentation, function entropy_get_entropy() fills a buffer with entropy, returns 0 on success, and returns -ERRNO on error. However, as shown in the following code, a missing error check take places.

zephyr/subsys/random/rand32_ctr_drbg.c

Lines 133 to 135 in 577d588

	entropy_get_entropy(entropy_driver,
	(void *)&entropy, sizeof(entropy));

Furthermore, the return values of function entropy_get_entropy() from other call sites are all checked. See the following code which is from the same file, for example.

zephyr/subsys/random/rand32_ctr_drbg.c

Lines 85 to 90 in 577d588

	ret = entropy_get_entropy(entropy_driver, (void *)&entropy,
	sizeof(entropy));
	if (ret != 0) {
	return -EIO;
	}

[carlescufi]

@Hxinrong would you mind sending a pull request for this?

[Hxinrong]

OK, thank you for your reply. Also, in the same file, seeing the following code, the return value of function tc_ctr_prng_reseed() is not checked before it is assigned by another function.

zephyr/subsys/random/rand32_ctr_drbg.c

Lines 136 to 148 in 577d588

	ret = tc_ctr_prng_reseed(&ctr_ctx,
	entropy,
	sizeof(entropy),
	drbg_seed,
	sizeof(drbg_seed));
	ret = tc_ctr_prng_generate(&ctr_ctx, 0, 0,
	(uint8_t *)dst, outlen);
	ret = (ret == TC_CRYPTO_SUCCESS) ? 0 : -EIO;
	} else {
	ret = -EIO;
	}