crypto: drbg - leave cipher handles operational

As the DRBG does not operate on shadow copies of the DRBG instance
any more, the cipher handles only need to be allocated once during
initalization time and deallocated during uninstantiate time.
Signed-off-by: NStephan Mueller <smueller@chronox.de>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

crypto/drbg.c

@@ -1249,11 +1249,6 @@ static int drbg_generate(struct drbg_state *drbg,
 	if ((drbg_max_requests(drbg)) < drbg->reseed_ctr)
 		drbg->seeded = false;
 
-	/* allocate cipher handle */
-	len = drbg->d_ops->crypto_init(drbg);
-	if (len)
-		goto err;
-
 	if (drbg->pr || !drbg->seeded) {
 		pr_devel("DRBG: reseeding before generation (prediction "
 			 "resistance: %s, state %s)\n",
@@ -1325,7 +1320,6 @@ static int drbg_generate(struct drbg_state *drbg,
 	 */
 	len = 0;
 err:
-	drbg->d_ops->crypto_fini(drbg);
 	return len;
 }
 
@@ -1424,9 +1418,10 @@ static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
 	if (drbg->d_ops->crypto_init(drbg))
 		goto err;
 	ret = drbg_seed(drbg, pers, false);
-	drbg->d_ops->crypto_fini(drbg);
-	if (ret)
+	if (ret) {
+		drbg->d_ops->crypto_fini(drbg);
 		goto err;
+	}
 
 	mutex_unlock(&drbg->drbg_mutex);
 	return 0;
@@ -1450,6 +1445,7 @@ static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
 static int drbg_uninstantiate(struct drbg_state *drbg)
 {
 	mutex_lock(&drbg->drbg_mutex);
+	drbg->d_ops->crypto_fini(drbg);
 	drbg_dealloc_state(drbg);
 	/* no scrubbing of test_data -- this shall survive an uninstantiate */
 	mutex_unlock(&drbg->drbg_mutex);