Code:  static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
 {
	struct crypto_rng *rng = __crypto_rng_cast(tfm);
	struct rng_alg *alg = crypto_rng_alg(rng);
	struct old_rng_alg *oalg = crypto_old_rng_alg(rng);
	if (oalg->rng_make_random) {
		rng->generate = generate;
		rng->seed = rngapi_reset;
		rng->seedsize = oalg->seedsize;
		return 0;
	}
	rng->generate = alg->generate;
	rng->seed = alg->seed;
	rng->seedsize = alg->seedsize;
 	return 0;
 }

Vulnerability Type: DoS 
CWE ID: CWE-476
Summary: The rngapi_reset function in crypto/rng.c in the Linux kernel before 4.2 allows attackers to cause a denial of service (NULL pointer dereference).
Commit Message: crypto: rng - Remove old low-level rng interface

Now that all rng implementations have switched over to the new
interface, we can remove the old low-level interface.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>