lib/crypto: blake2s: Adjust parameter order of blake2s()

Reorder the parameters of blake2s() from (out, in, key, outlen, inlen,
keylen) to (key, keylen, in, inlen, out, outlen).

This aligns BLAKE2s with the common conventions of pairing buffers and
their lengths, and having outputs follow inputs.  This is widely used
elsewhere in lib/crypto/ and crypto/, and even elsewhere in the BLAKE2s
code itself such as blake2s_init_key() and blake2s_final().  So
blake2s() was a bit of an exception.

Notably, this results in the same order as hmac_*_usingrawkey().

Note that since the type signature changed, it's not possible for a
blake2s() call site to be silently missed.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251018043106.375964-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

5 files changed, 17 insertions, 17 deletions

diff --git a/drivers/char/random.c b/drivers/char/random.c
index b8b24b6ed3fe..422c5c76571b 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -701,7 +701,7 @@ static void extract_entropy(void *buf, size_t len)
 
 	/* next_key = HASHPRF(seed, RDSEED || 0) */
 	block.counter = 0;
-	blake2s(next_key, (u8 *)&block, seed, sizeof(next_key), sizeof(block), sizeof(seed));
+	blake2s(seed, sizeof(seed), (const u8 *)&block, sizeof(block), next_key, sizeof(next_key));
 	blake2s_init_key(&input_pool.hash, BLAKE2S_HASH_SIZE, next_key, sizeof(next_key));
 
 	spin_unlock_irqrestore(&input_pool.lock, flags);
@@ -711,7 +711,7 @@ static void extract_entropy(void *buf, size_t len)
 		i = min_t(size_t, len, BLAKE2S_HASH_SIZE);
 		/* output = HASHPRF(seed, RDSEED || ++counter) */
 		++block.counter;
-		blake2s(buf, (u8 *)&block, seed, i, sizeof(block), sizeof(seed));
+		blake2s(seed, sizeof(seed), (const u8 *)&block, sizeof(block), buf, i);
 		len -= i;
 		buf += i;
 	}
diff --git a/drivers/net/wireguard/cookie.c b/drivers/net/wireguard/cookie.c
index 94d0a7206084..be1b83aae03b 100644
--- a/drivers/net/wireguard/cookie.c
+++ b/drivers/net/wireguard/cookie.c
@@ -77,7 +77,7 @@ static void compute_mac1(u8 mac1[COOKIE_LEN], const void *message, size_t len,
 {
 	len = len - sizeof(struct message_macs) +
 	      offsetof(struct message_macs, mac1);
-	blake2s(mac1, message, key, COOKIE_LEN, len, NOISE_SYMMETRIC_KEY_LEN);
+	blake2s(key, NOISE_SYMMETRIC_KEY_LEN, message, len, mac1, COOKIE_LEN);
 }
 
 static void compute_mac2(u8 mac2[COOKIE_LEN], const void *message, size_t len,
@@ -85,7 +85,7 @@ static void compute_mac2(u8 mac2[COOKIE_LEN], const void *message, size_t len,
 {
 	len = len - sizeof(struct message_macs) +
 	      offsetof(struct message_macs, mac2);
-	blake2s(mac2, message, cookie, COOKIE_LEN, len, COOKIE_LEN);
+	blake2s(cookie, COOKIE_LEN, message, len, mac2, COOKIE_LEN);
 }
 
 static void make_cookie(u8 cookie[COOKIE_LEN], struct sk_buff *skb,
diff --git a/drivers/net/wireguard/noise.c b/drivers/net/wireguard/noise.c
index 7eb9a23a3d4d..306abb876c80 100644
--- a/drivers/net/wireguard/noise.c
+++ b/drivers/net/wireguard/noise.c
@@ -35,8 +35,8 @@ void __init wg_noise_init(void)
 {
 	struct blake2s_state blake;
 
-	blake2s(handshake_init_chaining_key, handshake_name, NULL,
-		NOISE_HASH_LEN, sizeof(handshake_name), 0);
+	blake2s(NULL, 0, handshake_name, sizeof(handshake_name),
+		handshake_init_chaining_key, NOISE_HASH_LEN);
 	blake2s_init(&blake, NOISE_HASH_LEN);
 	blake2s_update(&blake, handshake_init_chaining_key, NOISE_HASH_LEN);
 	blake2s_update(&blake, identifier_name, sizeof(identifier_name));
diff --git a/include/crypto/blake2s.h b/include/crypto/blake2s.h
index f9ffd39194eb..a7dd678725b2 100644
--- a/include/crypto/blake2s.h
+++ b/include/crypto/blake2s.h
@@ -86,9 +86,9 @@ static inline void blake2s_init_key(struct blake2s_state *state,
 void blake2s_update(struct blake2s_state *state, const u8 *in, size_t inlen);
 void blake2s_final(struct blake2s_state *state, u8 *out);
 
-static inline void blake2s(u8 *out, const u8 *in, const u8 *key,
-			   const size_t outlen, const size_t inlen,
-			   const size_t keylen)
+static inline void blake2s(const u8 *key, const size_t keylen,
+			   const u8 *in, const size_t inlen,
+			   u8 *out, const size_t outlen)
 {
 	struct blake2s_state state;
 
diff --git a/lib/crypto/tests/blake2s_kunit.c b/lib/crypto/tests/blake2s_kunit.c
index 057c40132246..247bbdf7dc86 100644
--- a/lib/crypto/tests/blake2s_kunit.c
+++ b/lib/crypto/tests/blake2s_kunit.c
@@ -14,7 +14,7 @@
 static void blake2s_default(const u8 *data, size_t len,
 			    u8 out[BLAKE2S_HASH_SIZE])
 {
-	blake2s(out, data, NULL, BLAKE2S_HASH_SIZE, len, 0);
+	blake2s(NULL, 0, data, len, out, BLAKE2S_HASH_SIZE);
 }
 
 static void blake2s_init_default(struct blake2s_state *state)
@@ -52,7 +52,7 @@ static void test_blake2s_all_key_and_hash_lens(struct kunit *test)
 	for (int key_len = 0; key_len <= BLAKE2S_KEY_SIZE; key_len++) {
 		rand_bytes_seeded_from_len(key, key_len);
 		for (int out_len = 1; out_len <= BLAKE2S_HASH_SIZE; out_len++) {
-			blake2s(hash, data, key, out_len, data_len, key_len);
+			blake2s(key, key_len, data, data_len, hash, out_len);
 			blake2s_update(&main_state, hash, out_len);
 		}
 	}
@@ -80,10 +80,10 @@ static void test_blake2s_with_guarded_key_buf(struct kunit *test)
 		rand_bytes(key, key_len);
 		memcpy(guarded_key, key, key_len);
 
-		blake2s(hash1, test_buf, key,
-			BLAKE2S_HASH_SIZE, data_len, key_len);
-		blake2s(hash2, test_buf, guarded_key,
-			BLAKE2S_HASH_SIZE, data_len, key_len);
+		blake2s(key, key_len, test_buf, data_len,
+			hash1, BLAKE2S_HASH_SIZE);
+		blake2s(guarded_key, key_len, test_buf, data_len,
+			hash2, BLAKE2S_HASH_SIZE);
 		KUNIT_ASSERT_MEMEQ(test, hash1, hash2, BLAKE2S_HASH_SIZE);
 
 		blake2s_init_key(&state, BLAKE2S_HASH_SIZE,
@@ -107,8 +107,8 @@ static void test_blake2s_with_guarded_out_buf(struct kunit *test)
 		u8 hash[BLAKE2S_HASH_SIZE];
 		u8 *guarded_hash = &test_buf[TEST_BUF_LEN - out_len];
 
-		blake2s(hash, test_buf, NULL, out_len, data_len, 0);
-		blake2s(guarded_hash, test_buf, NULL, out_len, data_len, 0);
+		blake2s(NULL, 0, test_buf, data_len, hash, out_len);
+		blake2s(NULL, 0, test_buf, data_len, guarded_hash, out_len);
 		KUNIT_ASSERT_MEMEQ(test, hash, guarded_hash, out_len);
 	}
 }