crypto: lib/chacha - add array bounds to function prototypes

Add explicit array bounds to the function prototypes for the parameters
that didn't already get handled by the conversion to use chacha_state:

- chacha_block_*():
  Change 'u8 *out' or 'u8 *stream' to u8 out[CHACHA_BLOCK_SIZE].

- hchacha_block_*():
  Change 'u32 *out' or 'u32 *stream' to u32 out[HCHACHA_OUT_WORDS].

- chacha_init():
  Change 'const u32 *key' to 'const u32 key[CHACHA_KEY_WORDS]'.
  Change 'const u8 *iv' to 'const u8 iv[CHACHA_IV_SIZE]'.

No functional changes.  This just makes it clear when fixed-size arrays
are expected.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/arm/lib/crypto/chacha-glue.c

@@ -23,9 +23,9 @@ asmlinkage void chacha_4block_xor_neon(const struct chacha_state *state,
 				       u8 *dst, const u8 *src,
 				       int nrounds, unsigned int nbytes);
 asmlinkage void hchacha_block_arm(const struct chacha_state *state,
-				  u32 *out, int nrounds);
+				  u32 out[HCHACHA_OUT_WORDS], int nrounds);
 asmlinkage void hchacha_block_neon(const struct chacha_state *state,
-				   u32 *out, int nrounds);
+				   u32 out[HCHACHA_OUT_WORDS], int nrounds);
 
 asmlinkage void chacha_doarm(u8 *dst, const u8 *src, unsigned int bytes,
 			     const struct chacha_state *state, int nrounds);
@@ -64,14 +64,14 @@ static void chacha_doneon(struct chacha_state *state, u8 *dst, const u8 *src,
 	}
 }
 
-void hchacha_block_arch(const struct chacha_state *state, u32 *stream,
-			int nrounds)
+void hchacha_block_arch(const struct chacha_state *state,
+			u32 out[HCHACHA_OUT_WORDS], int nrounds)
 {
 	if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon_usable()) {
-		hchacha_block_arm(state, stream, nrounds);
+		hchacha_block_arm(state, out, nrounds);
 	} else {
 		kernel_neon_begin();
-		hchacha_block_neon(state, stream, nrounds);
+		hchacha_block_neon(state, out, nrounds);
 		kernel_neon_end();
 	}
 }

arch/arm/lib/crypto/chacha-scalar-core.S

@@ -408,7 +408,7 @@ ENDPROC(chacha_doarm)
 
 /*
  * void hchacha_block_arm(const struct chacha_state *state,
- *			  u32 out[8], int nrounds);
+ *			  u32 out[HCHACHA_OUT_WORDS], int nrounds);
  */
 ENTRY(hchacha_block_arm)
 	push		{r1,r4-r11,lr}

arch/arm64/lib/crypto/chacha-neon-glue.c

@@ -34,7 +34,7 @@ asmlinkage void chacha_4block_xor_neon(const struct chacha_state *state,
 				       u8 *dst, const u8 *src,
 				       int nrounds, int bytes);
 asmlinkage void hchacha_block_neon(const struct chacha_state *state,
-				   u32 *out, int nrounds);
+				   u32 out[HCHACHA_OUT_WORDS], int nrounds);
 
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
 
@@ -61,14 +61,14 @@ static void chacha_doneon(struct chacha_state *state, u8 *dst, const u8 *src,
 	}
 }
 
-void hchacha_block_arch(const struct chacha_state *state, u32 *stream,
-			int nrounds)
+void hchacha_block_arch(const struct chacha_state *state,
+			u32 out[HCHACHA_OUT_WORDS], int nrounds)
 {
 	if (!static_branch_likely(&have_neon) || !crypto_simd_usable()) {
-		hchacha_block_generic(state, stream, nrounds);
+		hchacha_block_generic(state, out, nrounds);
 	} else {
 		kernel_neon_begin();
-		hchacha_block_neon(state, stream, nrounds);
+		hchacha_block_neon(state, out, nrounds);
 		kernel_neon_end();
 	}
 }

arch/mips/lib/crypto/chacha-glue.c

@@ -15,7 +15,7 @@ asmlinkage void chacha_crypt_arch(struct chacha_state *state,
 EXPORT_SYMBOL(chacha_crypt_arch);
 
 asmlinkage void hchacha_block_arch(const struct chacha_state *state,
-				   u32 *stream, int nrounds);
+				   u32 out[HCHACHA_OUT_WORDS], int nrounds);
 EXPORT_SYMBOL(hchacha_block_arch);
 
 bool chacha_is_arch_optimized(void)

arch/powerpc/lib/crypto/chacha-p10-glue.c

@@ -49,9 +49,9 @@ static void chacha_p10_do_8x(struct chacha_state *state, u8 *dst, const u8 *src,
 }
 
 void hchacha_block_arch(const struct chacha_state *state,
-			u32 *stream, int nrounds)
+			u32 out[HCHACHA_OUT_WORDS], int nrounds)
 {
-	hchacha_block_generic(state, stream, nrounds);
+	hchacha_block_generic(state, out, nrounds);
 }
 EXPORT_SYMBOL(hchacha_block_arch);
 

arch/riscv/lib/crypto/chacha-riscv64-glue.c

@@ -18,7 +18,8 @@ static __ro_after_init DEFINE_STATIC_KEY_FALSE(use_zvkb);
 asmlinkage void chacha_zvkb(struct chacha_state *state, const u8 *in, u8 *out,
 			    size_t nblocks, int nrounds);
 
-void hchacha_block_arch(const struct chacha_state *state, u32 *out, int nrounds)
+void hchacha_block_arch(const struct chacha_state *state,
+			u32 out[HCHACHA_OUT_WORDS], int nrounds)
 {
 	hchacha_block_generic(state, out, nrounds);
 }

arch/s390/lib/crypto/chacha-glue.c

@@ -17,10 +17,10 @@
 #include "chacha-s390.h"
 
 void hchacha_block_arch(const struct chacha_state *state,
-			u32 *stream, int nrounds)
+			u32 out[HCHACHA_OUT_WORDS], int nrounds)
 {
 	/* TODO: implement hchacha_block_arch() in assembly */
-	hchacha_block_generic(state, stream, nrounds);
+	hchacha_block_generic(state, out, nrounds);
 }
 EXPORT_SYMBOL(hchacha_block_arch);
 

arch/x86/lib/crypto/chacha_glue.c

@@ -19,7 +19,7 @@ asmlinkage void chacha_4block_xor_ssse3(const struct chacha_state *state,
 					u8 *dst, const u8 *src,
 					unsigned int len, int nrounds);
 asmlinkage void hchacha_block_ssse3(const struct chacha_state *state,
-				    u32 *out, int nrounds);
+				    u32 out[HCHACHA_OUT_WORDS], int nrounds);
 
 asmlinkage void chacha_2block_xor_avx2(const struct chacha_state *state,
 				       u8 *dst, const u8 *src,
@@ -127,13 +127,13 @@ static void chacha_dosimd(struct chacha_state *state, u8 *dst, const u8 *src,
 }
 
 void hchacha_block_arch(const struct chacha_state *state,
-			u32 *stream, int nrounds)
+			u32 out[HCHACHA_OUT_WORDS], int nrounds)
 {
 	if (!static_branch_likely(&chacha_use_simd)) {
-		hchacha_block_generic(state, stream, nrounds);
+		hchacha_block_generic(state, out, nrounds);
 	} else {
 		kernel_fpu_begin();
-		hchacha_block_ssse3(state, stream, nrounds);
+		hchacha_block_ssse3(state, out, nrounds);
 		kernel_fpu_end();
 	}
 }

crypto/chacha.c

@@ -46,8 +46,8 @@ static int chacha12_setkey(struct crypto_skcipher *tfm,
 }
 
 static int chacha_stream_xor(struct skcipher_request *req,
-			     const struct chacha_ctx *ctx, const u8 *iv,
-			     bool arch)
+			     const struct chacha_ctx *ctx,
+			     const u8 iv[CHACHA_IV_SIZE], bool arch)
 {
 	struct skcipher_walk walk;
 	struct chacha_state state;

include/crypto/chacha.h

@@ -26,7 +26,9 @@
 #define CHACHA_BLOCK_SIZE	64
 #define CHACHAPOLY_IV_SIZE	12
 
-#define CHACHA_STATE_WORDS	(CHACHA_BLOCK_SIZE / sizeof(u32))
+#define CHACHA_KEY_WORDS	8
+#define CHACHA_STATE_WORDS	16
+#define HCHACHA_OUT_WORDS	8
 
 /* 192-bit nonce, then 64-bit stream position */
 #define XCHACHA_IV_SIZE		32
@@ -35,19 +37,21 @@ struct chacha_state {
 	u32 x[CHACHA_STATE_WORDS];
 };
 
-void chacha_block_generic(struct chacha_state *state, u8 *stream, int nrounds);
-static inline void chacha20_block(struct chacha_state *state, u8 *stream)
+void chacha_block_generic(struct chacha_state *state,
+			  u8 out[CHACHA_BLOCK_SIZE], int nrounds);
+static inline void chacha20_block(struct chacha_state *state,
+				  u8 out[CHACHA_BLOCK_SIZE])
 {
-	chacha_block_generic(state, stream, 20);
+	chacha_block_generic(state, out, 20);
 }
 
-void hchacha_block_arch(const struct chacha_state *state, u32 *out,
-			int nrounds);
-void hchacha_block_generic(const struct chacha_state *state, u32 *out,
-			   int nrounds);
+void hchacha_block_arch(const struct chacha_state *state,
+			u32 out[HCHACHA_OUT_WORDS], int nrounds);
+void hchacha_block_generic(const struct chacha_state *state,
+			   u32 out[HCHACHA_OUT_WORDS], int nrounds);
 
-static inline void hchacha_block(const struct chacha_state *state, u32 *out,
-				 int nrounds)
+static inline void hchacha_block(const struct chacha_state *state,
+				 u32 out[HCHACHA_OUT_WORDS], int nrounds)
 {
 	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))
 		hchacha_block_arch(state, out, nrounds);
@@ -71,7 +75,8 @@ static inline void chacha_init_consts(struct chacha_state *state)
 }
 
 static inline void chacha_init(struct chacha_state *state,
-			       const u32 *key, const u8 *iv)
+			       const u32 key[CHACHA_KEY_WORDS],
+			       const u8 iv[CHACHA_IV_SIZE])
 {
 	chacha_init_consts(state);
 	state->x[4]  = key[0];

lib/crypto/chacha.c

@@ -67,14 +67,15 @@ static void chacha_permute(struct chacha_state *state, int nrounds)
 /**
  * chacha_block_generic - generate one keystream block and increment block counter
  * @state: input state matrix
- * @stream: output keystream block (64 bytes)
+ * @out: output keystream block
  * @nrounds: number of rounds (20 or 12; 20 is recommended)
  *
  * This is the ChaCha core, a function from 64-byte strings to 64-byte strings.
  * The caller has already converted the endianness of the input.  This function
  * also handles incrementing the block counter in the input matrix.
  */
-void chacha_block_generic(struct chacha_state *state, u8 *stream, int nrounds)
+void chacha_block_generic(struct chacha_state *state,
+			  u8 out[CHACHA_BLOCK_SIZE], int nrounds)
 {
 	struct chacha_state permuted_state = *state;
 	int i;
@@ -83,7 +84,7 @@ void chacha_block_generic(struct chacha_state *state, u8 *stream, int nrounds)
 
 	for (i = 0; i < ARRAY_SIZE(state->x); i++)
 		put_unaligned_le32(permuted_state.x[i] + state->x[i],
-				   &stream[i * sizeof(u32)]);
+				   &out[i * sizeof(u32)]);
 
 	state->x[12]++;
 }
@@ -92,7 +93,7 @@ EXPORT_SYMBOL(chacha_block_generic);
 /**
  * hchacha_block_generic - abbreviated ChaCha core, for XChaCha
  * @state: input state matrix
- * @stream: output (8 32-bit words)
+ * @out: the output words
  * @nrounds: number of rounds (20 or 12; 20 is recommended)
  *
  * HChaCha is the ChaCha equivalent of HSalsa and is an intermediate step
@@ -101,13 +102,13 @@ EXPORT_SYMBOL(chacha_block_generic);
  * of the state.  It should not be used for streaming directly.
  */
 void hchacha_block_generic(const struct chacha_state *state,
-			   u32 *stream, int nrounds)
+			   u32 out[HCHACHA_OUT_WORDS], int nrounds)
 {
 	struct chacha_state permuted_state = *state;
 
 	chacha_permute(&permuted_state, nrounds);
 
-	memcpy(&stream[0], &permuted_state.x[0], 16);
-	memcpy(&stream[4], &permuted_state.x[12], 16);
+	memcpy(&out[0], &permuted_state.x[0], 16);
+	memcpy(&out[4], &permuted_state.x[12], 16);
 }
 EXPORT_SYMBOL(hchacha_block_generic);

lib/crypto/chacha20poly1305.c

@@ -18,8 +18,6 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 
-#define CHACHA_KEY_WORDS	(CHACHA_KEY_SIZE / sizeof(u32))
-
 static void chacha_load_key(u32 *k, const u8 *in)
 {
 	k[0] = get_unaligned_le32(in);