1 files changed, 70 insertions, 79 deletions

diff --git a/crypto/drbg.c b/crypto/drbg.c
index 04379ca624cd..df80752fb649 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1035,17 +1035,38 @@ static const struct drbg_state_ops drbg_hash_ops = {
  ******************************************************************/
 
 static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
-			      int reseed)
+			      int reseed, enum drbg_seed_state new_seed_state)
 {
 	int ret = drbg->d_ops->update(drbg, seed, reseed);
 
 	if (ret)
 		return ret;
 
-	drbg->seeded = true;
+	drbg->seeded = new_seed_state;
 	/* 10.1.1.2 / 10.1.1.3 step 5 */
 	drbg->reseed_ctr = 1;
 
+	switch (drbg->seeded) {
+	case DRBG_SEED_STATE_UNSEEDED:
+		/* Impossible, but handle it to silence compiler warnings. */
+		fallthrough;
+	case DRBG_SEED_STATE_PARTIAL:
+		/*
+		 * Require frequent reseeds until the seed source is
+		 * fully initialized.
+		 */
+		drbg->reseed_threshold = 50;
+		break;
+
+	case DRBG_SEED_STATE_FULL:
+		/*
+		 * Seed source has become fully initialized, frequent
+		 * reseeds no longer required.
+		 */
+		drbg->reseed_threshold = drbg_max_requests(drbg);
+		break;
+	}
+
 	return ret;
 }
 
@@ -1065,12 +1086,10 @@ static inline int drbg_get_random_bytes(struct drbg_state *drbg,
 	return 0;
 }
 
-static void drbg_async_seed(struct work_struct *work)
+static int drbg_seed_from_random(struct drbg_state *drbg)
 {
 	struct drbg_string data;
 	LIST_HEAD(seedlist);
-	struct drbg_state *drbg = container_of(work, struct drbg_state,
-					       seed_work);
 	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
 	unsigned char entropy[32];
 	int ret;
@@ -1081,30 +1100,15 @@ static void drbg_async_seed(struct work_struct *work)
 	drbg_string_fill(&data, entropy, entropylen);
 	list_add_tail(&data.list, &seedlist);
 
-	mutex_lock(&drbg->drbg_mutex);
-
 	ret = drbg_get_random_bytes(drbg, entropy, entropylen);
 	if (ret)
-		goto unlock;
-
-	/* If nonblocking pool is initialized, deactivate Jitter RNG */
-	crypto_free_rng(drbg->jent);
-	drbg->jent = NULL;
-
-	/* Set seeded to false so that if __drbg_seed fails the
-	 * next generate call will trigger a reseed.
-	 */
-	drbg->seeded = false;
+		goto out;
 
-	__drbg_seed(drbg, &seedlist, true);
-
-	if (drbg->seeded)
-		drbg->reseed_threshold = drbg_max_requests(drbg);
-
-unlock:
-	mutex_unlock(&drbg->drbg_mutex);
+	ret = __drbg_seed(drbg, &seedlist, true, DRBG_SEED_STATE_FULL);
 
+out:
 	memzero_explicit(entropy, entropylen);
+	return ret;
 }
 
 /*
@@ -1126,6 +1130,7 @@ static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
 	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
 	struct drbg_string data1;
 	LIST_HEAD(seedlist);
+	enum drbg_seed_state new_seed_state = DRBG_SEED_STATE_FULL;
 
 	/* 9.1 / 9.2 / 9.3.1 step 3 */
 	if (pers && pers->len > (drbg_max_addtl(drbg))) {
@@ -1153,6 +1158,9 @@ static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
 		BUG_ON((entropylen * 2) > sizeof(entropy));
 
 		/* Get seed from in-kernel /dev/urandom */
+		if (!rng_is_initialized())
+			new_seed_state = DRBG_SEED_STATE_PARTIAL;
+
 		ret = drbg_get_random_bytes(drbg, entropy, entropylen);
 		if (ret)
 			goto out;
@@ -1168,7 +1176,23 @@ static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
 						   entropylen);
 			if (ret) {
 				pr_devel("DRBG: jent failed with %d\n", ret);
-				goto out;
+
+				/*
+				 * Do not treat the transient failure of the
+				 * Jitter RNG as an error that needs to be
+				 * reported. The combined number of the
+				 * maximum reseed threshold times the maximum
+				 * number of Jitter RNG transient errors is
+				 * less than the reseed threshold required by
+				 * SP800-90A allowing us to treat the
+				 * transient errors as such.
+				 *
+				 * However, we mandate that at least the first
+				 * seeding operation must succeed with the
+				 * Jitter RNG.
+				 */
+				if (!reseed || ret != -EAGAIN)
+					goto out;
 			}
 
 			drbg_string_fill(&data1, entropy, entropylen * 2);
@@ -1193,7 +1217,7 @@ static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
 		memset(drbg->C, 0, drbg_statelen(drbg));
 	}
 
-	ret = __drbg_seed(drbg, &seedlist, reseed);
+	ret = __drbg_seed(drbg, &seedlist, reseed, new_seed_state);
 
 out:
 	memzero_explicit(entropy, entropylen * 2);
@@ -1373,19 +1397,25 @@ static int drbg_generate(struct drbg_state *drbg,
 	 * here. The spec is a bit convoluted here, we make it simpler.
 	 */
 	if (drbg->reseed_threshold < drbg->reseed_ctr)
-		drbg->seeded = false;
+		drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
 
-	if (drbg->pr || !drbg->seeded) {
+	if (drbg->pr || drbg->seeded == DRBG_SEED_STATE_UNSEEDED) {
 		pr_devel("DRBG: reseeding before generation (prediction "
 			 "resistance: %s, state %s)\n",
 			 drbg->pr ? "true" : "false",
-			 drbg->seeded ? "seeded" : "unseeded");
+			 (drbg->seeded ==  DRBG_SEED_STATE_FULL ?
+			  "seeded" : "unseeded"));
 		/* 9.3.1 steps 7.1 through 7.3 */
 		len = drbg_seed(drbg, addtl, true);
 		if (len)
 			goto err;
 		/* 9.3.1 step 7.4 */
 		addtl = NULL;
+	} else if (rng_is_initialized() &&
+		   drbg->seeded == DRBG_SEED_STATE_PARTIAL) {
+		len = drbg_seed_from_random(drbg);
+		if (len)
+			goto err;
 	}
 
 	if (addtl && 0 < addtl->len)
@@ -1478,51 +1508,23 @@ static int drbg_generate_long(struct drbg_state *drbg,
 	return 0;
 }
 
-static void drbg_schedule_async_seed(struct random_ready_callback *rdy)
-{
-	struct drbg_state *drbg = container_of(rdy, struct drbg_state,
-					       random_ready);
-
-	schedule_work(&drbg->seed_work);
-}
-
 static int drbg_prepare_hrng(struct drbg_state *drbg)
 {
-	int err;
-
 	/* We do not need an HRNG in test mode. */
 	if (list_empty(&drbg->test_data.list))
 		return 0;
 
-	INIT_WORK(&drbg->seed_work, drbg_async_seed);
-
-	drbg->random_ready.owner = THIS_MODULE;
-	drbg->random_ready.func = drbg_schedule_async_seed;
-
-	err = add_random_ready_callback(&drbg->random_ready);
-
-	switch (err) {
-	case 0:
-		break;
-
-	case -EALREADY:
-		err = 0;
-		/* fall through */
-
-	default:
-		drbg->random_ready.func = NULL;
-		return err;
-	}
-
 	drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
+	if (IS_ERR(drbg->jent)) {
+		const int err = PTR_ERR(drbg->jent);
 
-	/*
-	 * Require frequent reseeds until the seed source is fully
-	 * initialized.
-	 */
-	drbg->reseed_threshold = 50;
+		drbg->jent = NULL;
+		if (fips_enabled)
+			return err;
+		pr_info("DRBG: Continuing without Jitter RNG\n");
+	}
 
-	return err;
+	return 0;
 }
 
 /*
@@ -1565,7 +1567,7 @@ static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
 	if (!drbg->core) {
 		drbg->core = &drbg_cores[coreref];
 		drbg->pr = pr;
-		drbg->seeded = false;
+		drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
 		drbg->reseed_threshold = drbg_max_requests(drbg);
 
 		ret = drbg_alloc_state(drbg);
@@ -1576,14 +1578,6 @@ static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
 		if (ret)
 			goto free_everything;
 
-		if (IS_ERR(drbg->jent)) {
-			ret = PTR_ERR(drbg->jent);
-			drbg->jent = NULL;
-			if (fips_enabled || ret != -ENOENT)
-				goto free_everything;
-			pr_info("DRBG: Continuing without Jitter RNG\n");
-		}
-
 		reseed = false;
 	}
 
@@ -1616,12 +1610,9 @@ free_everything:
  */
 static int drbg_uninstantiate(struct drbg_state *drbg)
 {
-	if (drbg->random_ready.func) {
-		del_random_ready_callback(&drbg->random_ready);
-		cancel_work_sync(&drbg->seed_work);
+	if (!IS_ERR_OR_NULL(drbg->jent))
 		crypto_free_rng(drbg->jent);
-		drbg->jent = NULL;
-	}
+	drbg->jent = NULL;
 
 	if (drbg->d_ops)
 		drbg->d_ops->crypto_fini(drbg);