crypto: testmgr - fix RNG performance in fuzz tests

Commit Message

Eric Biggers Feb. 27, 2023, 5:50 a.m. UTC

From: Eric Biggers <[e-mail]>

The performance of the crypto fuzz tests has greatly regressed since
v5.18.  When booting a kernel on an arm64 dev board with all software
crypto algorithms and CONFIG_CRYPTO_MANAGER_EXTRA_TESTS enabled, the
fuzz tests now take about 200 seconds to run, or about 325 seconds with
lockdep enabled, compared to about 5 seconds before.

The root cause is that the random number generation has become much
slower due to commit d4150779e60f ("random32: use real rng for
non-deterministic randomness").  On my same arm64 dev board, at the time
the fuzz tests are run, get_random_u8() is about 345x slower than
prandom_u32_state(), or about 469x if lockdep is enabled.

Lockdep makes a big difference, but much of the rest comes from the
get_random_*() functions taking a *very* slow path when the CRNG is not
yet initialized.  Since the crypto self-tests run early during boot,
even having a hardware RNG driver enabled (CONFIG_CRYPTO_DEV_QCOM_RNG in
my case) doesn't prevent this.  x86 systems don't have this issue, but
they still see a significant regression if lockdep is enabled.

Converting the "Fully random bytes" case in generate_random_bytes() to
use get_random_bytes() helps significantly, improving the test time to
about 27 seconds.  But that's still over 5x slower than before.

This is all a bit silly, though, since the fuzz tests don't actually
need cryptographically secure random numbers.  So let's just make them
use a non-cryptographically-secure RNG as they did before.  The original
prandom_u32() is gone now, so let's use prandom_u32_state() instead,
with an explicitly managed state, like various other self-tests in the
kernel source tree (rbtree_test.c, test_scanf.c, etc.) already do.  This
also has the benefit that no locking is required anymore, so performance
should be even better than the original version that used prandom_u32().

Fixes: d4150779e60f ("random32: use real rng for non-deterministic randomness")
Cc: [e-mail]
Signed-off-by: Eric Biggers <[e-mail]>
---
 crypto/testmgr.c | 268 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 171 insertions(+), 97 deletions(-)


base-commit: 2fcd07b7ccd5fd10b2120d298363e4e6c53ccf9c

Comments

Yann Droneaud Feb. 27, 2023, 8:13 a.m. UTC | #1

Hi,

27 février 2023 à 06:52 "Eric Biggers" <[e-mail]> a écrit:
> 
> From: Eric Biggers <[e-mail]>
> 
> The performance of the crypto fuzz tests has greatly regressed since
> v5.18. When booting a kernel on an arm64 dev board with all software
> crypto algorithms and CONFIG_CRYPTO_MANAGER_EXTRA_TESTS enabled, the
> fuzz tests now take about 200 seconds to run, or about 325 seconds with
> lockdep enabled, compared to about 5 seconds before.
> 
> The root cause is that the random number generation has become much
> slower due to commit d4150779e60f ("random32: use real rng for
> non-deterministic randomness"). On my same arm64 dev board, at the time
> the fuzz tests are run, get_random_u8() is about 345x slower than
> prandom_u32_state(), or about 469x if lockdep is enabled.
> 
> Lockdep makes a big difference, but much of the rest comes from the
> get_random_*() functions taking a *very* slow path when the CRNG is not
> yet initialized. Since the crypto self-tests run early during boot,
> even having a hardware RNG driver enabled (CONFIG_CRYPTO_DEV_QCOM_RNG in
> my case) doesn't prevent this. x86 systems don't have this issue, but
> they still see a significant regression if lockdep is enabled.
> 
> Converting the "Fully random bytes" case in generate_random_bytes() to
> use get_random_bytes() helps significantly, improving the test time to
> about 27 seconds. But that's still over 5x slower than before.
> 
> This is all a bit silly, though, since the fuzz tests don't actually
> need cryptographically secure random numbers. So let's just make them
> use a non-cryptographically-secure RNG as they did before. The original
> prandom_u32() is gone now, so let's use prandom_u32_state() instead,
> with an explicitly managed state, like various other self-tests in the
> kernel source tree (rbtree_test.c, test_scanf.c, etc.) already do. This
> also has the benefit that no locking is required anymore, so performance
> should be even better than the original version that used prandom_u32().
> 
> Fixes: d4150779e60f ("random32: use real rng for non-deterministic randomness")
> Cc: [e-mail]
> Signed-off-by: Eric Biggers <[e-mail]>
> ---
>  crypto/testmgr.c | 268 ++++++++++++++++++++++++++++++-----------------
>  1 file changed, 171 insertions(+), 97 deletions(-)
> 
> diff --git a/crypto/testmgr.c b/crypto/testmgr.c
> index c91e93ece20b..2cbd2f8ce3c3 100644
> --- a/crypto/testmgr.c
> +++ b/crypto/testmgr.c
> @@ -860,12 +860,52 @@ static int prepare_keybuf(const u8 *key, unsigned int ksize,
>  
>  #ifdef CONFIG_CRYPTO_MANAGER_EXTRA_TESTS
>  
> +/*
> + * The fuzz tests use prandom instead of the normal Linux RNG since they don't
> + * need cryptographically secure random numbers. This greatly improves the
> + * performance of these tests, especially if they are run before the Linux RNG
> + * has been initialized or if they are run on a lockdep-enabled kernel.
> + */
> +
> +static inline void init_rnd_state(struct rnd_state *rng)
> +{
> + static atomic64_t next_seed;
> +
> + prandom_seed_state(rng, atomic64_inc_return(&next_seed));

Isn't making this deterministic defeating the purpose of fuzzing ?

Regards.

Eric Biggers Feb. 27, 2023, 6:19 p.m. UTC | #2

On Mon, Feb 27, 2023 at 08:13:41AM +0000, Yann Droneaud wrote:
> > +/*
> > + * The fuzz tests use prandom instead of the normal Linux RNG since they don't
> > + * need cryptographically secure random numbers. This greatly improves the
> > + * performance of these tests, especially if they are run before the Linux RNG
> > + * has been initialized or if they are run on a lockdep-enabled kernel.
> > + */
> > +
> > +static inline void init_rnd_state(struct rnd_state *rng)
> > +{
> > + static atomic64_t next_seed;
> > +
> > + prandom_seed_state(rng, atomic64_inc_return(&next_seed));
> 
> Isn't making this deterministic defeating the purpose of fuzzing ?
> 
> Regards.

No, it's still fuzzing.  It just means that you'll no longer get different test
cases each individual time you boot the kernel.  Which seems like mostly a good
thing, since it makes test failures reproducible.

This seemed like the obvious thing to do now that we're not using an API that
doesn't provide this option.  Though now that you draw attention to it, there is
indeed a tradeoff that rare bugs will be harder to find.  I suppose that making
it deterministic ought to be a separate patch so that this one isn't doing two
different things.  I'll make this patch use get_random_u64() here instead.

- Eric

Patch

diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index c91e93ece20b..2cbd2f8ce3c3 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -860,12 +860,52 @@  static int prepare_keybuf(const u8 *key, unsigned int ksize,
 
 #ifdef CONFIG_CRYPTO_MANAGER_EXTRA_TESTS
 
+/*
+ * The fuzz tests use prandom instead of the normal Linux RNG since they don't
+ * need cryptographically secure random numbers.  This greatly improves the
+ * performance of these tests, especially if they are run before the Linux RNG
+ * has been initialized or if they are run on a lockdep-enabled kernel.
+ */
+
+static inline void init_rnd_state(struct rnd_state *rng)
+{
+	static atomic64_t next_seed;
+
+	prandom_seed_state(rng, atomic64_inc_return(&next_seed));
+}
+
+static inline u8 prandom_u8(struct rnd_state *rng)
+{
+	return prandom_u32_state(rng);
+}
+
+static inline u32 prandom_u32_below(struct rnd_state *rng, u32 n)
+{
+	/*
+	 * This is slightly biased for non-power-of-2 values of n, but this
+	 * isn't important here.
+	 */
+	return prandom_u32_state(rng) % n;
+}
+
+static inline bool prandom_bool(struct rnd_state *rng)
+{
+	return prandom_u32_below(rng, 2);
+}
+
+static inline u32 prandom_u32_inclusive(struct rnd_state *rng,
+					u32 floor, u32 ceil)
+{
+	return floor + prandom_u32_below(rng, ceil - floor + 1);
+}
+
 /* Generate a random length in range [0, max_len], but prefer smaller values */
-static unsigned int generate_random_length(unsigned int max_len)
+static unsigned int generate_random_length(struct rnd_state *rng,
+					   unsigned int max_len)
 {
-	unsigned int len = get_random_u32_below(max_len + 1);
+	unsigned int len = prandom_u32_below(rng, max_len + 1);
 
-	switch (get_random_u32_below(4)) {
+	switch (prandom_u32_below(rng, 4)) {
 	case 0:
 		return len % 64;
 	case 1:
@@ -878,43 +918,44 @@  static unsigned int generate_random_length(unsigned int max_len)
 }
 
 /* Flip a random bit in the given nonempty data buffer */
-static void flip_random_bit(u8 *buf, size_t size)
+static void flip_random_bit(struct rnd_state *rng, u8 *buf, size_t size)
 {
 	size_t bitpos;
 
-	bitpos = get_random_u32_below(size * 8);
+	bitpos = prandom_u32_below(rng, size * 8);
 	buf[bitpos / 8] ^= 1 << (bitpos % 8);
 }
 
 /* Flip a random byte in the given nonempty data buffer */
-static void flip_random_byte(u8 *buf, size_t size)
+static void flip_random_byte(struct rnd_state *rng, u8 *buf, size_t size)
 {
-	buf[get_random_u32_below(size)] ^= 0xff;
+	buf[prandom_u32_below(rng, size)] ^= 0xff;
 }
 
 /* Sometimes make some random changes to the given nonempty data buffer */
-static void mutate_buffer(u8 *buf, size_t size)
+static void mutate_buffer(struct rnd_state *rng, u8 *buf, size_t size)
 {
 	size_t num_flips;
 	size_t i;
 
 	/* Sometimes flip some bits */
-	if (get_random_u32_below(4) == 0) {
-		num_flips = min_t(size_t, 1 << get_random_u32_below(8), size * 8);
+	if (prandom_u32_below(rng, 4) == 0) {
+		num_flips = min_t(size_t, 1 << prandom_u32_below(rng, 8),
+				  size * 8);
 		for (i = 0; i < num_flips; i++)
-			flip_random_bit(buf, size);
+			flip_random_bit(rng, buf, size);
 	}
 
 	/* Sometimes flip some bytes */
-	if (get_random_u32_below(4) == 0) {
-		num_flips = min_t(size_t, 1 << get_random_u32_below(8), size);
+	if (prandom_u32_below(rng, 4) == 0) {
+		num_flips = min_t(size_t, 1 << prandom_u32_below(rng, 8), size);
 		for (i = 0; i < num_flips; i++)
-			flip_random_byte(buf, size);
+			flip_random_byte(rng, buf, size);
 	}
 }
 
 /* Randomly generate 'count' bytes, but sometimes make them "interesting" */
-static void generate_random_bytes(u8 *buf, size_t count)
+static void generate_random_bytes(struct rnd_state *rng, u8 *buf, size_t count)
 {
 	u8 b;
 	u8 increment;
@@ -923,11 +964,11 @@  static void generate_random_bytes(u8 *buf, size_t count)
 	if (count == 0)
 		return;
 
-	switch (get_random_u32_below(8)) { /* Choose a generation strategy */
+	switch (prandom_u32_below(rng, 8)) { /* Choose a generation strategy */
 	case 0:
 	case 1:
 		/* All the same byte, plus optional mutations */
-		switch (get_random_u32_below(4)) {
+		switch (prandom_u32_below(rng, 4)) {
 		case 0:
 			b = 0x00;
 			break;
@@ -935,28 +976,28 @@  static void generate_random_bytes(u8 *buf, size_t count)
 			b = 0xff;
 			break;
 		default:
-			b = get_random_u8();
+			b = prandom_u8(rng);
 			break;
 		}
 		memset(buf, b, count);
-		mutate_buffer(buf, count);
+		mutate_buffer(rng, buf, count);
 		break;
 	case 2:
 		/* Ascending or descending bytes, plus optional mutations */
-		increment = get_random_u8();
-		b = get_random_u8();
+		increment = prandom_u8(rng);
+		b = prandom_u8(rng);
 		for (i = 0; i < count; i++, b += increment)
 			buf[i] = b;
-		mutate_buffer(buf, count);
+		mutate_buffer(rng, buf, count);
 		break;
 	default:
 		/* Fully random bytes */
-		for (i = 0; i < count; i++)
-			buf[i] = get_random_u8();
+		prandom_bytes_state(rng, buf, count);
 	}
 }
 
-static char *generate_random_sgl_divisions(struct test_sg_division *divs,
+static char *generate_random_sgl_divisions(struct rnd_state *rng,
+					   struct test_sg_division *divs,
 					   size_t max_divs, char *p, char *end,
 					   bool gen_flushes, u32 req_flags)
 {
@@ -967,24 +1008,26 @@  static char *generate_random_sgl_divisions(struct test_sg_division *divs,
 		unsigned int this_len;
 		const char *flushtype_str;
 
-		if (div == &divs[max_divs - 1] || get_random_u32_below(2) == 0)
+		if (div == &divs[max_divs - 1] || prandom_bool(rng))
 			this_len = remaining;
 		else
-			this_len = get_random_u32_inclusive(1, remaining);
+			this_len = prandom_u32_inclusive(rng, 1, remaining);
 		div->proportion_of_total = this_len;
 
-		if (get_random_u32_below(4) == 0)
-			div->offset = get_random_u32_inclusive(PAGE_SIZE - 128, PAGE_SIZE - 1);
-		else if (get_random_u32_below(2) == 0)
-			div->offset = get_random_u32_below(32);
+		if (prandom_u32_below(rng, 4) == 0)
+			div->offset = prandom_u32_inclusive(rng,
+							    PAGE_SIZE - 128,
+							    PAGE_SIZE - 1);
+		else if (prandom_bool(rng))
+			div->offset = prandom_u32_below(rng, 32);
 		else
-			div->offset = get_random_u32_below(PAGE_SIZE);
-		if (get_random_u32_below(8) == 0)
+			div->offset = prandom_u32_below(rng, PAGE_SIZE);
+		if (prandom_u32_below(rng, 8) == 0)
 			div->offset_relative_to_alignmask = true;
 
 		div->flush_type = FLUSH_TYPE_NONE;
 		if (gen_flushes) {
-			switch (get_random_u32_below(4)) {
+			switch (prandom_u32_below(rng, 4)) {
 			case 0:
 				div->flush_type = FLUSH_TYPE_REIMPORT;
 				break;
@@ -996,7 +1039,7 @@  static char *generate_random_sgl_divisions(struct test_sg_division *divs,
 
 		if (div->flush_type != FLUSH_TYPE_NONE &&
 		    !(req_flags & CRYPTO_TFM_REQ_MAY_SLEEP) &&
-		    get_random_u32_below(2) == 0)
+		    prandom_bool(rng))
 			div->nosimd = true;
 
 		switch (div->flush_type) {
@@ -1031,7 +1074,8 @@  static char *generate_random_sgl_divisions(struct test_sg_division *divs,
 }
 
 /* Generate a random testvec_config for fuzz testing */
-static void generate_random_testvec_config(struct testvec_config *cfg,
+static void generate_random_testvec_config(struct rnd_state *rng,
+					   struct testvec_config *cfg,
 					   char *name, size_t max_namelen)
 {
 	char *p = name;
@@ -1043,7 +1087,7 @@  static void generate_random_testvec_config(struct testvec_config *cfg,
 
 	p += scnprintf(p, end - p, "random:");
 
-	switch (get_random_u32_below(4)) {
+	switch (prandom_u32_below(rng, 4)) {
 	case 0:
 	case 1:
 		cfg->inplace_mode = OUT_OF_PLACE;
@@ -1058,12 +1102,12 @@  static void generate_random_testvec_config(struct testvec_config *cfg,
 		break;
 	}
 
-	if (get_random_u32_below(2) == 0) {
+	if (prandom_bool(rng)) {
 		cfg->req_flags |= CRYPTO_TFM_REQ_MAY_SLEEP;
 		p += scnprintf(p, end - p, " may_sleep");
 	}
 
-	switch (get_random_u32_below(4)) {
+	switch (prandom_u32_below(rng, 4)) {
 	case 0:
 		cfg->finalization_type = FINALIZATION_TYPE_FINAL;
 		p += scnprintf(p, end - p, " use_final");
@@ -1078,36 +1122,37 @@  static void generate_random_testvec_config(struct testvec_config *cfg,
 		break;
 	}
 
-	if (!(cfg->req_flags & CRYPTO_TFM_REQ_MAY_SLEEP) &&
-	    get_random_u32_below(2) == 0) {
+	if (!(cfg->req_flags & CRYPTO_TFM_REQ_MAY_SLEEP) && prandom_bool(rng)) {
 		cfg->nosimd = true;
 		p += scnprintf(p, end - p, " nosimd");
 	}
 
 	p += scnprintf(p, end - p, " src_divs=[");
-	p = generate_random_sgl_divisions(cfg->src_divs,
+	p = generate_random_sgl_divisions(rng, cfg->src_divs,
 					  ARRAY_SIZE(cfg->src_divs), p, end,
 					  (cfg->finalization_type !=
 					   FINALIZATION_TYPE_DIGEST),
 					  cfg->req_flags);
 	p += scnprintf(p, end - p, "]");
 
-	if (cfg->inplace_mode == OUT_OF_PLACE && get_random_u32_below(2) == 0) {
+	if (cfg->inplace_mode == OUT_OF_PLACE && prandom_bool(rng)) {
 		p += scnprintf(p, end - p, " dst_divs=[");
-		p = generate_random_sgl_divisions(cfg->dst_divs,
+		p = generate_random_sgl_divisions(rng, cfg->dst_divs,
 						  ARRAY_SIZE(cfg->dst_divs),
 						  p, end, false,
 						  cfg->req_flags);
 		p += scnprintf(p, end - p, "]");
 	}
 
-	if (get_random_u32_below(2) == 0) {
-		cfg->iv_offset = get_random_u32_inclusive(1, MAX_ALGAPI_ALIGNMASK);
+	if (prandom_bool(rng)) {
+		cfg->iv_offset = prandom_u32_inclusive(rng, 1,
+						       MAX_ALGAPI_ALIGNMASK);
 		p += scnprintf(p, end - p, " iv_offset=%u", cfg->iv_offset);
 	}
 
-	if (get_random_u32_below(2) == 0) {
-		cfg->key_offset = get_random_u32_inclusive(1, MAX_ALGAPI_ALIGNMASK);
+	if (prandom_bool(rng)) {
+		cfg->key_offset = prandom_u32_inclusive(rng, 1,
+							MAX_ALGAPI_ALIGNMASK);
 		p += scnprintf(p, end - p, " key_offset=%u", cfg->key_offset);
 	}
 
@@ -1620,11 +1665,14 @@  static int test_hash_vec(const struct hash_testvec *vec, unsigned int vec_num,
 
 #ifdef CONFIG_CRYPTO_MANAGER_EXTRA_TESTS
 	if (!noextratests) {
+		struct rnd_state rng;
 		struct testvec_config cfg;
 		char cfgname[TESTVEC_CONFIG_NAMELEN];
 
+		init_rnd_state(&rng);
+
 		for (i = 0; i < fuzz_iterations; i++) {
-			generate_random_testvec_config(&cfg, cfgname,
+			generate_random_testvec_config(&rng, &cfg, cfgname,
 						       sizeof(cfgname));
 			err = test_hash_vec_cfg(vec, vec_name, &cfg,
 						req, desc, tsgl, hashstate);
@@ -1642,15 +1690,16 @@  static int test_hash_vec(const struct hash_testvec *vec, unsigned int vec_num,
  * Generate a hash test vector from the given implementation.
  * Assumes the buffers in 'vec' were already allocated.
  */
-static void generate_random_hash_testvec(struct shash_desc *desc,
+static void generate_random_hash_testvec(struct rnd_state *rng,
+					 struct shash_desc *desc,
 					 struct hash_testvec *vec,
 					 unsigned int maxkeysize,
 					 unsigned int maxdatasize,
 					 char *name, size_t max_namelen)
 {
 	/* Data */
-	vec->psize = generate_random_length(maxdatasize);
-	generate_random_bytes((u8 *)vec->plaintext, vec->psize);
+	vec->psize = generate_random_length(rng, maxdatasize);
+	generate_random_bytes(rng, (u8 *)vec->plaintext, vec->psize);
 
 	/*
 	 * Key: length in range [1, maxkeysize], but usually choose maxkeysize.
@@ -1660,9 +1709,9 @@  static void generate_random_hash_testvec(struct shash_desc *desc,
 	vec->ksize = 0;
 	if (maxkeysize) {
 		vec->ksize = maxkeysize;
-		if (get_random_u32_below(4) == 0)
-			vec->ksize = get_random_u32_inclusive(1, maxkeysize);
-		generate_random_bytes((u8 *)vec->key, vec->ksize);
+		if (prandom_u32_below(rng, 4) == 0)
+			vec->ksize = prandom_u32_inclusive(rng, 1, maxkeysize);
+		generate_random_bytes(rng, (u8 *)vec->key, vec->ksize);
 
 		vec->setkey_error = crypto_shash_setkey(desc->tfm, vec->key,
 							vec->ksize);
@@ -1696,6 +1745,7 @@  static int test_hash_vs_generic_impl(const char *generic_driver,
 	const unsigned int maxdatasize = (2 * PAGE_SIZE) - TESTMGR_POISON_LEN;
 	const char *algname = crypto_hash_alg_common(tfm)->base.cra_name;
 	const char *driver = crypto_ahash_driver_name(tfm);
+	struct rnd_state rng;
 	char _generic_driver[CRYPTO_MAX_ALG_NAME];
 	struct crypto_shash *generic_tfm = NULL;
 	struct shash_desc *generic_desc = NULL;
@@ -1709,6 +1759,8 @@  static int test_hash_vs_generic_impl(const char *generic_driver,
 	if (noextratests)
 		return 0;
 
+	init_rnd_state(&rng);
+
 	if (!generic_driver) { /* Use default naming convention? */
 		err = build_generic_driver_name(algname, _generic_driver);
 		if (err)
@@ -1777,10 +1829,11 @@  static int test_hash_vs_generic_impl(const char *generic_driver,
 	}
 
 	for (i = 0; i < fuzz_iterations * 8; i++) {
-		generate_random_hash_testvec(generic_desc, &vec,
+		generate_random_hash_testvec(&rng, generic_desc, &vec,
 					     maxkeysize, maxdatasize,
 					     vec_name, sizeof(vec_name));
-		generate_random_testvec_config(cfg, cfgname, sizeof(cfgname));
+		generate_random_testvec_config(&rng, cfg, cfgname,
+					       sizeof(cfgname));
 
 		err = test_hash_vec_cfg(&vec, vec_name, cfg,
 					req, desc, tsgl, hashstate);
@@ -2182,11 +2235,14 @@  static int test_aead_vec(int enc, const struct aead_testvec *vec,
 
 #ifdef CONFIG_CRYPTO_MANAGER_EXTRA_TESTS
 	if (!noextratests) {
+		struct rnd_state rng;
 		struct testvec_config cfg;
 		char cfgname[TESTVEC_CONFIG_NAMELEN];
 
+		init_rnd_state(&rng);
+
 		for (i = 0; i < fuzz_iterations; i++) {
-			generate_random_testvec_config(&cfg, cfgname,
+			generate_random_testvec_config(&rng, &cfg, cfgname,
 						       sizeof(cfgname));
 			err = test_aead_vec_cfg(enc, vec, vec_name,
 						&cfg, req, tsgls);
@@ -2202,6 +2258,7 @@  static int test_aead_vec(int enc, const struct aead_testvec *vec,
 #ifdef CONFIG_CRYPTO_MANAGER_EXTRA_TESTS
 
 struct aead_extra_tests_ctx {
+	struct rnd_state rng;
 	struct aead_request *req;
 	struct crypto_aead *tfm;
 	const struct alg_test_desc *test_desc;
@@ -2220,24 +2277,26 @@  struct aead_extra_tests_ctx {
  * here means the full ciphertext including the authentication tag.  The
  * authentication tag (and hence also the ciphertext) is assumed to be nonempty.
  */
-static void mutate_aead_message(struct aead_testvec *vec, bool aad_iv,
+static void mutate_aead_message(struct rnd_state *rng,
+				struct aead_testvec *vec, bool aad_iv,
 				unsigned int ivsize)
 {
 	const unsigned int aad_tail_size = aad_iv ? ivsize : 0;
 	const unsigned int authsize = vec->clen - vec->plen;
 
-	if (get_random_u32_below(2) == 0 && vec->alen > aad_tail_size) {
+	if (prandom_bool(rng) && vec->alen > aad_tail_size) {
 		 /* Mutate the AAD */
-		flip_random_bit((u8 *)vec->assoc, vec->alen - aad_tail_size);
-		if (get_random_u32_below(2) == 0)
+		flip_random_bit(rng, (u8 *)vec->assoc,
+				vec->alen - aad_tail_size);
+		if (prandom_bool(rng))
 			return;
 	}
-	if (get_random_u32_below(2) == 0) {
+	if (prandom_bool(rng)) {
 		/* Mutate auth tag (assuming it's at the end of ciphertext) */
-		flip_random_bit((u8 *)vec->ctext + vec->plen, authsize);
+		flip_random_bit(rng, (u8 *)vec->ctext + vec->plen, authsize);
 	} else {
 		/* Mutate any part of the ciphertext */
-		flip_random_bit((u8 *)vec->ctext, vec->clen);
+		flip_random_bit(rng, (u8 *)vec->ctext, vec->clen);
 	}
 }
 
@@ -2248,7 +2307,8 @@  static void mutate_aead_message(struct aead_testvec *vec, bool aad_iv,
  */
 #define MIN_COLLISION_FREE_AUTHSIZE 8
 
-static void generate_aead_message(struct aead_request *req,
+static void generate_aead_message(struct rnd_state *rng,
+				  struct aead_request *req,
 				  const struct aead_test_suite *suite,
 				  struct aead_testvec *vec,
 				  bool prefer_inauthentic)
@@ -2257,17 +2317,18 @@  static void generate_aead_message(struct aead_request *req,
 	const unsigned int ivsize = crypto_aead_ivsize(tfm);
 	const unsigned int authsize = vec->clen - vec->plen;
 	const bool inauthentic = (authsize >= MIN_COLLISION_FREE_AUTHSIZE) &&
-				 (prefer_inauthentic || get_random_u32_below(4) == 0);
+				 (prefer_inauthentic ||
+				  prandom_u32_below(rng, 4) == 0);
 
 	/* Generate the AAD. */
-	generate_random_bytes((u8 *)vec->assoc, vec->alen);
+	generate_random_bytes(rng, (u8 *)vec->assoc, vec->alen);
 	if (suite->aad_iv && vec->alen >= ivsize)
 		/* Avoid implementation-defined behavior. */
 		memcpy((u8 *)vec->assoc + vec->alen - ivsize, vec->iv, ivsize);
 
-	if (inauthentic && get_random_u32_below(2) == 0) {
+	if (inauthentic && prandom_bool(rng)) {
 		/* Generate a random ciphertext. */
-		generate_random_bytes((u8 *)vec->ctext, vec->clen);
+		generate_random_bytes(rng, (u8 *)vec->ctext, vec->clen);
 	} else {
 		int i = 0;
 		struct scatterlist src[2], dst;
@@ -2279,7 +2340,7 @@  static void generate_aead_message(struct aead_request *req,
 		if (vec->alen)
 			sg_set_buf(&src[i++], vec->assoc, vec->alen);
 		if (vec->plen) {
-			generate_random_bytes((u8 *)vec->ptext, vec->plen);
+			generate_random_bytes(rng, (u8 *)vec->ptext, vec->plen);
 			sg_set_buf(&src[i++], vec->ptext, vec->plen);
 		}
 		sg_init_one(&dst, vec->ctext, vec->alen + vec->clen);
@@ -2299,7 +2360,7 @@  static void generate_aead_message(struct aead_request *req,
 		 * Mutate the authentic (ciphertext, AAD) pair to get an
 		 * inauthentic one.
 		 */
-		mutate_aead_message(vec, suite->aad_iv, ivsize);
+		mutate_aead_message(rng, vec, suite->aad_iv, ivsize);
 	}
 	vec->novrfy = 1;
 	if (suite->einval_allowed)
@@ -2313,7 +2374,8 @@  static void generate_aead_message(struct aead_request *req,
  * If 'prefer_inauthentic' is true, then this function will generate inauthentic
  * test vectors (i.e. vectors with 'vec->novrfy=1') more often.
  */
-static void generate_random_aead_testvec(struct aead_request *req,
+static void generate_random_aead_testvec(struct rnd_state *rng,
+					 struct aead_request *req,
 					 struct aead_testvec *vec,
 					 const struct aead_test_suite *suite,
 					 unsigned int maxkeysize,
@@ -2329,18 +2391,18 @@  static void generate_random_aead_testvec(struct aead_request *req,
 
 	/* Key: length in [0, maxkeysize], but usually choose maxkeysize */
 	vec->klen = maxkeysize;
-	if (get_random_u32_below(4) == 0)
-		vec->klen = get_random_u32_below(maxkeysize + 1);
-	generate_random_bytes((u8 *)vec->key, vec->klen);
+	if (prandom_u32_below(rng, 4) == 0)
+		vec->klen = prandom_u32_below(rng, maxkeysize + 1);
+	generate_random_bytes(rng, (u8 *)vec->key, vec->klen);
 	vec->setkey_error = crypto_aead_setkey(tfm, vec->key, vec->klen);
 
 	/* IV */
-	generate_random_bytes((u8 *)vec->iv, ivsize);
+	generate_random_bytes(rng, (u8 *)vec->iv, ivsize);
 
 	/* Tag length: in [0, maxauthsize], but usually choose maxauthsize */
 	authsize = maxauthsize;
-	if (get_random_u32_below(4) == 0)
-		authsize = get_random_u32_below(maxauthsize + 1);
+	if (prandom_u32_below(rng, 4) == 0)
+		authsize = prandom_u32_below(rng, maxauthsize + 1);
 	if (prefer_inauthentic && authsize < MIN_COLLISION_FREE_AUTHSIZE)
 		authsize = MIN_COLLISION_FREE_AUTHSIZE;
 	if (WARN_ON(authsize > maxdatasize))
@@ -2349,11 +2411,11 @@  static void generate_random_aead_testvec(struct aead_request *req,
 	vec->setauthsize_error = crypto_aead_setauthsize(tfm, authsize);
 
 	/* AAD, plaintext, and ciphertext lengths */
-	total_len = generate_random_length(maxdatasize);
-	if (get_random_u32_below(4) == 0)
+	total_len = generate_random_length(rng, maxdatasize);
+	if (prandom_u32_below(rng, 4) == 0)
 		vec->alen = 0;
 	else
-		vec->alen = generate_random_length(total_len);
+		vec->alen = generate_random_length(rng, total_len);
 	vec->plen = total_len - vec->alen;
 	vec->clen = vec->plen + authsize;
 
@@ -2364,7 +2426,7 @@  static void generate_random_aead_testvec(struct aead_request *req,
 	vec->novrfy = 0;
 	vec->crypt_error = 0;
 	if (vec->setkey_error == 0 && vec->setauthsize_error == 0)
-		generate_aead_message(req, suite, vec, prefer_inauthentic);
+		generate_aead_message(rng, req, suite, vec, prefer_inauthentic);
 	snprintf(name, max_namelen,
 		 "\"random: alen=%u plen=%u authsize=%u klen=%u novrfy=%d\"",
 		 vec->alen, vec->plen, authsize, vec->klen, vec->novrfy);
@@ -2376,7 +2438,7 @@  static void try_to_generate_inauthentic_testvec(
 	int i;
 
 	for (i = 0; i < 10; i++) {
-		generate_random_aead_testvec(ctx->req, &ctx->vec,
+		generate_random_aead_testvec(&ctx->rng, ctx->req, &ctx->vec,
 					     &ctx->test_desc->suite.aead,
 					     ctx->maxkeysize, ctx->maxdatasize,
 					     ctx->vec_name,
@@ -2407,7 +2469,8 @@  static int test_aead_inauthentic_inputs(struct aead_extra_tests_ctx *ctx)
 		 */
 		try_to_generate_inauthentic_testvec(ctx);
 		if (ctx->vec.novrfy) {
-			generate_random_testvec_config(&ctx->cfg, ctx->cfgname,
+			generate_random_testvec_config(&ctx->rng, &ctx->cfg,
+						       ctx->cfgname,
 						       sizeof(ctx->cfgname));
 			err = test_aead_vec_cfg(DECRYPT, &ctx->vec,
 						ctx->vec_name, &ctx->cfg,
@@ -2497,12 +2560,13 @@  static int test_aead_vs_generic_impl(struct aead_extra_tests_ctx *ctx)
 	 * the other implementation against them.
 	 */
 	for (i = 0; i < fuzz_iterations * 8; i++) {
-		generate_random_aead_testvec(generic_req, &ctx->vec,
+		generate_random_aead_testvec(&ctx->rng, generic_req, &ctx->vec,
 					     &ctx->test_desc->suite.aead,
 					     ctx->maxkeysize, ctx->maxdatasize,
 					     ctx->vec_name,
 					     sizeof(ctx->vec_name), false);
-		generate_random_testvec_config(&ctx->cfg, ctx->cfgname,
+		generate_random_testvec_config(&ctx->rng, &ctx->cfg,
+					       ctx->cfgname,
 					       sizeof(ctx->cfgname));
 		if (!ctx->vec.novrfy) {
 			err = test_aead_vec_cfg(ENCRYPT, &ctx->vec,
@@ -2541,6 +2605,7 @@  static int test_aead_extra(const struct alg_test_desc *test_desc,
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return -ENOMEM;
+	init_rnd_state(&ctx->rng);
 	ctx->req = req;
 	ctx->tfm = crypto_aead_reqtfm(req);
 	ctx->test_desc = test_desc;
@@ -2930,11 +2995,14 @@  static int test_skcipher_vec(int enc, const struct cipher_testvec *vec,
 
 #ifdef CONFIG_CRYPTO_MANAGER_EXTRA_TESTS
 	if (!noextratests) {
+		struct rnd_state rng;
 		struct testvec_config cfg;
 		char cfgname[TESTVEC_CONFIG_NAMELEN];
 
+		init_rnd_state(&rng);
+
 		for (i = 0; i < fuzz_iterations; i++) {
-			generate_random_testvec_config(&cfg, cfgname,
+			generate_random_testvec_config(&rng, &cfg, cfgname,
 						       sizeof(cfgname));
 			err = test_skcipher_vec_cfg(enc, vec, vec_name,
 						    &cfg, req, tsgls);
@@ -2952,7 +3020,8 @@  static int test_skcipher_vec(int enc, const struct cipher_testvec *vec,
  * Generate a symmetric cipher test vector from the given implementation.
  * Assumes the buffers in 'vec' were already allocated.
  */
-static void generate_random_cipher_testvec(struct skcipher_request *req,
+static void generate_random_cipher_testvec(struct rnd_state *rng,
+					   struct skcipher_request *req,
 					   struct cipher_testvec *vec,
 					   unsigned int maxdatasize,
 					   char *name, size_t max_namelen)
@@ -2966,17 +3035,17 @@  static void generate_random_cipher_testvec(struct skcipher_request *req,
 
 	/* Key: length in [0, maxkeysize], but usually choose maxkeysize */
 	vec->klen = maxkeysize;
-	if (get_random_u32_below(4) == 0)
-		vec->klen = get_random_u32_below(maxkeysize + 1);
-	generate_random_bytes((u8 *)vec->key, vec->klen);
+	if (prandom_u32_below(rng, 4) == 0)
+		vec->klen = prandom_u32_below(rng, maxkeysize + 1);
+	generate_random_bytes(rng, (u8 *)vec->key, vec->klen);
 	vec->setkey_error = crypto_skcipher_setkey(tfm, vec->key, vec->klen);
 
 	/* IV */
-	generate_random_bytes((u8 *)vec->iv, ivsize);
+	generate_random_bytes(rng, (u8 *)vec->iv, ivsize);
 
 	/* Plaintext */
-	vec->len = generate_random_length(maxdatasize);
-	generate_random_bytes((u8 *)vec->ptext, vec->len);
+	vec->len = generate_random_length(rng, maxdatasize);
+	generate_random_bytes(rng, (u8 *)vec->ptext, vec->len);
 
 	/* If the key couldn't be set, no need to continue to encrypt. */
 	if (vec->setkey_error)
@@ -3018,6 +3087,7 @@  static int test_skcipher_vs_generic_impl(const char *generic_driver,
 	const unsigned int maxdatasize = (2 * PAGE_SIZE) - TESTMGR_POISON_LEN;
 	const char *algname = crypto_skcipher_alg(tfm)->base.cra_name;
 	const char *driver = crypto_skcipher_driver_name(tfm);
+	struct rnd_state rng;
 	char _generic_driver[CRYPTO_MAX_ALG_NAME];
 	struct crypto_skcipher *generic_tfm = NULL;
 	struct skcipher_request *generic_req = NULL;
@@ -3035,6 +3105,8 @@  static int test_skcipher_vs_generic_impl(const char *generic_driver,
 	if (strncmp(algname, "kw(", 3) == 0)
 		return 0;
 
+	init_rnd_state(&rng);
+
 	if (!generic_driver) { /* Use default naming convention? */
 		err = build_generic_driver_name(algname, _generic_driver);
 		if (err)
@@ -3119,9 +3191,11 @@  static int test_skcipher_vs_generic_impl(const char *generic_driver,
 	}
 
 	for (i = 0; i < fuzz_iterations * 8; i++) {
-		generate_random_cipher_testvec(generic_req, &vec, maxdatasize,
+		generate_random_cipher_testvec(&rng, generic_req, &vec,
+					       maxdatasize,
 					       vec_name, sizeof(vec_name));
-		generate_random_testvec_config(cfg, cfgname, sizeof(cfgname));
+		generate_random_testvec_config(&rng, cfg, cfgname,
+					       sizeof(cfgname));
 
 		err = test_skcipher_vec_cfg(ENCRYPT, &vec, vec_name,
 					    cfg, req, tsgls);