Code:  int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
 {
 	u8 *buf = NULL;
	int err;

	if (!seed && slen) {
		buf = kmalloc(slen, GFP_KERNEL);
		if (!buf)
			return -ENOMEM;

		get_random_bytes(buf, slen);
 		seed = buf;
 	}
 
	err = tfm->seed(tfm, seed, slen);
 
 	kfree(buf);
 	return err;
}

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>