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* [PATCH] lib/crypto: sha2: Add hmac_sha*_init_usingrawkey()
@ 2025-07-11 21:58 Eric Biggers
  2025-07-14  5:24 ` Ard Biesheuvel
  0 siblings, 1 reply; 2+ messages in thread
From: Eric Biggers @ 2025-07-11 21:58 UTC (permalink / raw)
  To: linux-crypto
  Cc: linux-kernel, Ard Biesheuvel, Jason A . Donenfeld, Eric Biggers

While the HMAC library functions support both incremental and one-shot
computation and both prepared and raw keys, the combination of raw key
+ incremental was missing.  It turns out that several potential users of
the HMAC library functions (tpm2-sessions.c, smb2transport.c,
trusted_tpm1.c) want exactly that.

Therefore, add the missing functions hmac_sha*_init_usingrawkey().

Implement them in an optimized way that directly initializes the HMAC
context without a separate key preparation step.

Reimplement the one-shot raw key functions hmac_sha*_usingrawkey() on
top of the new functions, which makes them a bit more efficient.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 include/crypto/sha2.h | 60 +++++++++++++++++++++++++++++++++++++++++++
 lib/crypto/sha256.c   | 53 ++++++++++++++++++++++++++------------
 lib/crypto/sha512.c   | 55 +++++++++++++++++++++++++++------------
 3 files changed, 134 insertions(+), 34 deletions(-)

diff --git a/include/crypto/sha2.h b/include/crypto/sha2.h
index e0a08f6addd00..15e461e568cca 100644
--- a/include/crypto/sha2.h
+++ b/include/crypto/sha2.h
@@ -245,10 +245,25 @@ static inline void hmac_sha224_init(struct hmac_sha224_ctx *ctx,
 				    const struct hmac_sha224_key *key)
 {
 	__hmac_sha256_init(&ctx->ctx, &key->key);
 }
 
+/**
+ * hmac_sha224_init_usingrawkey() - Initialize an HMAC-SHA224 context for a new
+ *				    message, using a raw key
+ * @ctx: (output) the HMAC context to initialize
+ * @raw_key: the raw HMAC-SHA224 key
+ * @raw_key_len: the key length in bytes.  All key lengths are supported.
+ *
+ * If you don't need incremental computation, consider hmac_sha224_usingrawkey()
+ * instead.
+ *
+ * Context: Any context.
+ */
+void hmac_sha224_init_usingrawkey(struct hmac_sha224_ctx *ctx,
+				  const u8 *raw_key, size_t raw_key_len);
+
 /**
  * hmac_sha224_update() - Update an HMAC-SHA224 context with message data
  * @ctx: the HMAC context to update; must have been initialized
  * @data: the message data
  * @data_len: the data length in bytes
@@ -403,10 +418,25 @@ static inline void hmac_sha256_init(struct hmac_sha256_ctx *ctx,
 				    const struct hmac_sha256_key *key)
 {
 	__hmac_sha256_init(&ctx->ctx, &key->key);
 }
 
+/**
+ * hmac_sha256_init_usingrawkey() - Initialize an HMAC-SHA256 context for a new
+ *				    message, using a raw key
+ * @ctx: (output) the HMAC context to initialize
+ * @raw_key: the raw HMAC-SHA256 key
+ * @raw_key_len: the key length in bytes.  All key lengths are supported.
+ *
+ * If you don't need incremental computation, consider hmac_sha256_usingrawkey()
+ * instead.
+ *
+ * Context: Any context.
+ */
+void hmac_sha256_init_usingrawkey(struct hmac_sha256_ctx *ctx,
+				  const u8 *raw_key, size_t raw_key_len);
+
 /**
  * hmac_sha256_update() - Update an HMAC-SHA256 context with message data
  * @ctx: the HMAC context to update; must have been initialized
  * @data: the message data
  * @data_len: the data length in bytes
@@ -595,10 +625,25 @@ static inline void hmac_sha384_init(struct hmac_sha384_ctx *ctx,
 				    const struct hmac_sha384_key *key)
 {
 	__hmac_sha512_init(&ctx->ctx, &key->key);
 }
 
+/**
+ * hmac_sha384_init_usingrawkey() - Initialize an HMAC-SHA384 context for a new
+ *				    message, using a raw key
+ * @ctx: (output) the HMAC context to initialize
+ * @raw_key: the raw HMAC-SHA384 key
+ * @raw_key_len: the key length in bytes.  All key lengths are supported.
+ *
+ * If you don't need incremental computation, consider hmac_sha384_usingrawkey()
+ * instead.
+ *
+ * Context: Any context.
+ */
+void hmac_sha384_init_usingrawkey(struct hmac_sha384_ctx *ctx,
+				  const u8 *raw_key, size_t raw_key_len);
+
 /**
  * hmac_sha384_update() - Update an HMAC-SHA384 context with message data
  * @ctx: the HMAC context to update; must have been initialized
  * @data: the message data
  * @data_len: the data length in bytes
@@ -753,10 +798,25 @@ static inline void hmac_sha512_init(struct hmac_sha512_ctx *ctx,
 				    const struct hmac_sha512_key *key)
 {
 	__hmac_sha512_init(&ctx->ctx, &key->key);
 }
 
+/**
+ * hmac_sha512_init_usingrawkey() - Initialize an HMAC-SHA512 context for a new
+ *				    message, using a raw key
+ * @ctx: (output) the HMAC context to initialize
+ * @raw_key: the raw HMAC-SHA512 key
+ * @raw_key_len: the key length in bytes.  All key lengths are supported.
+ *
+ * If you don't need incremental computation, consider hmac_sha512_usingrawkey()
+ * instead.
+ *
+ * Context: Any context.
+ */
+void hmac_sha512_init_usingrawkey(struct hmac_sha512_ctx *ctx,
+				  const u8 *raw_key, size_t raw_key_len);
+
 /**
  * hmac_sha512_update() - Update an HMAC-SHA512 context with message data
  * @ctx: the HMAC context to update; must have been initialized
  * @data: the message data
  * @data_len: the data length in bytes
diff --git a/lib/crypto/sha256.c b/lib/crypto/sha256.c
index 808438d4f4278..8fa15165d23e8 100644
--- a/lib/crypto/sha256.c
+++ b/lib/crypto/sha256.c
@@ -261,11 +261,12 @@ void sha256(const u8 *data, size_t len, u8 out[SHA256_DIGEST_SIZE])
 }
 EXPORT_SYMBOL(sha256);
 
 /* pre-boot environment (as indicated by __DISABLE_EXPORTS) doesn't need HMAC */
 #ifndef __DISABLE_EXPORTS
-static void __hmac_sha256_preparekey(struct __hmac_sha256_key *key,
+static void __hmac_sha256_preparekey(struct sha256_block_state *istate,
+				     struct sha256_block_state *ostate,
 				     const u8 *raw_key, size_t raw_key_len,
 				     const struct sha256_block_state *iv)
 {
 	union {
 		u8 b[SHA256_BLOCK_SIZE];
@@ -281,33 +282,35 @@ static void __hmac_sha256_preparekey(struct __hmac_sha256_key *key,
 		memcpy(derived_key.b, raw_key, raw_key_len);
 	}
 
 	for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
 		derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE);
-	key->istate = *iv;
-	sha256_blocks(&key->istate, derived_key.b, 1);
+	*istate = *iv;
+	sha256_blocks(istate, derived_key.b, 1);
 
 	for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
 		derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^
 						HMAC_IPAD_VALUE);
-	key->ostate = *iv;
-	sha256_blocks(&key->ostate, derived_key.b, 1);
+	*ostate = *iv;
+	sha256_blocks(ostate, derived_key.b, 1);
 
 	memzero_explicit(&derived_key, sizeof(derived_key));
 }
 
 void hmac_sha224_preparekey(struct hmac_sha224_key *key,
 			    const u8 *raw_key, size_t raw_key_len)
 {
-	__hmac_sha256_preparekey(&key->key, raw_key, raw_key_len, &sha224_iv);
+	__hmac_sha256_preparekey(&key->key.istate, &key->key.ostate,
+				 raw_key, raw_key_len, &sha224_iv);
 }
 EXPORT_SYMBOL_GPL(hmac_sha224_preparekey);
 
 void hmac_sha256_preparekey(struct hmac_sha256_key *key,
 			    const u8 *raw_key, size_t raw_key_len)
 {
-	__hmac_sha256_preparekey(&key->key, raw_key, raw_key_len, &sha256_iv);
+	__hmac_sha256_preparekey(&key->key.istate, &key->key.ostate,
+				 raw_key, raw_key_len, &sha256_iv);
 }
 EXPORT_SYMBOL_GPL(hmac_sha256_preparekey);
 
 void __hmac_sha256_init(struct __hmac_sha256_ctx *ctx,
 			const struct __hmac_sha256_key *key)
@@ -315,10 +318,28 @@ void __hmac_sha256_init(struct __hmac_sha256_ctx *ctx,
 	__sha256_init(&ctx->sha_ctx, &key->istate, SHA256_BLOCK_SIZE);
 	ctx->ostate = key->ostate;
 }
 EXPORT_SYMBOL_GPL(__hmac_sha256_init);
 
+void hmac_sha224_init_usingrawkey(struct hmac_sha224_ctx *ctx,
+				  const u8 *raw_key, size_t raw_key_len)
+{
+	__hmac_sha256_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
+				 raw_key, raw_key_len, &sha224_iv);
+	ctx->ctx.sha_ctx.bytecount = SHA256_BLOCK_SIZE;
+}
+EXPORT_SYMBOL_GPL(hmac_sha224_init_usingrawkey);
+
+void hmac_sha256_init_usingrawkey(struct hmac_sha256_ctx *ctx,
+				  const u8 *raw_key, size_t raw_key_len)
+{
+	__hmac_sha256_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
+				 raw_key, raw_key_len, &sha256_iv);
+	ctx->ctx.sha_ctx.bytecount = SHA256_BLOCK_SIZE;
+}
+EXPORT_SYMBOL_GPL(hmac_sha256_init_usingrawkey);
+
 static void __hmac_sha256_final(struct __hmac_sha256_ctx *ctx,
 				u8 *out, size_t digest_size)
 {
 	/* Generate the padded input for the outer hash in ctx->sha_ctx.buf. */
 	__sha256_final(&ctx->sha_ctx, ctx->sha_ctx.buf, digest_size);
@@ -374,29 +395,27 @@ EXPORT_SYMBOL_GPL(hmac_sha256);
 
 void hmac_sha224_usingrawkey(const u8 *raw_key, size_t raw_key_len,
 			     const u8 *data, size_t data_len,
 			     u8 out[SHA224_DIGEST_SIZE])
 {
-	struct hmac_sha224_key key;
-
-	hmac_sha224_preparekey(&key, raw_key, raw_key_len);
-	hmac_sha224(&key, data, data_len, out);
+	struct hmac_sha224_ctx ctx;
 
-	memzero_explicit(&key, sizeof(key));
+	hmac_sha224_init_usingrawkey(&ctx, raw_key, raw_key_len);
+	hmac_sha224_update(&ctx, data, data_len);
+	hmac_sha224_final(&ctx, out);
 }
 EXPORT_SYMBOL_GPL(hmac_sha224_usingrawkey);
 
 void hmac_sha256_usingrawkey(const u8 *raw_key, size_t raw_key_len,
 			     const u8 *data, size_t data_len,
 			     u8 out[SHA256_DIGEST_SIZE])
 {
-	struct hmac_sha256_key key;
-
-	hmac_sha256_preparekey(&key, raw_key, raw_key_len);
-	hmac_sha256(&key, data, data_len, out);
+	struct hmac_sha256_ctx ctx;
 
-	memzero_explicit(&key, sizeof(key));
+	hmac_sha256_init_usingrawkey(&ctx, raw_key, raw_key_len);
+	hmac_sha256_update(&ctx, data, data_len);
+	hmac_sha256_final(&ctx, out);
 }
 EXPORT_SYMBOL_GPL(hmac_sha256_usingrawkey);
 #endif /* !__DISABLE_EXPORTS */
 
 #ifdef sha256_mod_init_arch
diff --git a/lib/crypto/sha512.c b/lib/crypto/sha512.c
index d514721491ca0..d8062188be98a 100644
--- a/lib/crypto/sha512.c
+++ b/lib/crypto/sha512.c
@@ -247,11 +247,12 @@ void sha512(const u8 *data, size_t len, u8 out[SHA512_DIGEST_SIZE])
 	sha512_update(&ctx, data, len);
 	sha512_final(&ctx, out);
 }
 EXPORT_SYMBOL_GPL(sha512);
 
-static void __hmac_sha512_preparekey(struct __hmac_sha512_key *key,
+static void __hmac_sha512_preparekey(struct sha512_block_state *istate,
+				     struct sha512_block_state *ostate,
 				     const u8 *raw_key, size_t raw_key_len,
 				     const struct sha512_block_state *iv)
 {
 	union {
 		u8 b[SHA512_BLOCK_SIZE];
@@ -267,33 +268,35 @@ static void __hmac_sha512_preparekey(struct __hmac_sha512_key *key,
 		memcpy(derived_key.b, raw_key, raw_key_len);
 	}
 
 	for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
 		derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE);
-	key->istate = *iv;
-	sha512_blocks(&key->istate, derived_key.b, 1);
+	*istate = *iv;
+	sha512_blocks(istate, derived_key.b, 1);
 
 	for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
 		derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^
 						HMAC_IPAD_VALUE);
-	key->ostate = *iv;
-	sha512_blocks(&key->ostate, derived_key.b, 1);
+	*ostate = *iv;
+	sha512_blocks(ostate, derived_key.b, 1);
 
 	memzero_explicit(&derived_key, sizeof(derived_key));
 }
 
 void hmac_sha384_preparekey(struct hmac_sha384_key *key,
 			    const u8 *raw_key, size_t raw_key_len)
 {
-	__hmac_sha512_preparekey(&key->key, raw_key, raw_key_len, &sha384_iv);
+	__hmac_sha512_preparekey(&key->key.istate, &key->key.ostate,
+				 raw_key, raw_key_len, &sha384_iv);
 }
 EXPORT_SYMBOL_GPL(hmac_sha384_preparekey);
 
 void hmac_sha512_preparekey(struct hmac_sha512_key *key,
 			    const u8 *raw_key, size_t raw_key_len)
 {
-	__hmac_sha512_preparekey(&key->key, raw_key, raw_key_len, &sha512_iv);
+	__hmac_sha512_preparekey(&key->key.istate, &key->key.ostate,
+				 raw_key, raw_key_len, &sha512_iv);
 }
 EXPORT_SYMBOL_GPL(hmac_sha512_preparekey);
 
 void __hmac_sha512_init(struct __hmac_sha512_ctx *ctx,
 			const struct __hmac_sha512_key *key)
@@ -301,10 +304,30 @@ void __hmac_sha512_init(struct __hmac_sha512_ctx *ctx,
 	__sha512_init(&ctx->sha_ctx, &key->istate, SHA512_BLOCK_SIZE);
 	ctx->ostate = key->ostate;
 }
 EXPORT_SYMBOL_GPL(__hmac_sha512_init);
 
+void hmac_sha384_init_usingrawkey(struct hmac_sha384_ctx *ctx,
+				  const u8 *raw_key, size_t raw_key_len)
+{
+	__hmac_sha512_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
+				 raw_key, raw_key_len, &sha384_iv);
+	ctx->ctx.sha_ctx.bytecount_lo = SHA512_BLOCK_SIZE;
+	ctx->ctx.sha_ctx.bytecount_hi = 0;
+}
+EXPORT_SYMBOL_GPL(hmac_sha384_init_usingrawkey);
+
+void hmac_sha512_init_usingrawkey(struct hmac_sha512_ctx *ctx,
+				  const u8 *raw_key, size_t raw_key_len)
+{
+	__hmac_sha512_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
+				 raw_key, raw_key_len, &sha512_iv);
+	ctx->ctx.sha_ctx.bytecount_lo = SHA512_BLOCK_SIZE;
+	ctx->ctx.sha_ctx.bytecount_hi = 0;
+}
+EXPORT_SYMBOL_GPL(hmac_sha512_init_usingrawkey);
+
 static void __hmac_sha512_final(struct __hmac_sha512_ctx *ctx,
 				u8 *out, size_t digest_size)
 {
 	/* Generate the padded input for the outer hash in ctx->sha_ctx.buf. */
 	__sha512_final(&ctx->sha_ctx, ctx->sha_ctx.buf, digest_size);
@@ -360,29 +383,27 @@ EXPORT_SYMBOL_GPL(hmac_sha512);
 
 void hmac_sha384_usingrawkey(const u8 *raw_key, size_t raw_key_len,
 			     const u8 *data, size_t data_len,
 			     u8 out[SHA384_DIGEST_SIZE])
 {
-	struct hmac_sha384_key key;
-
-	hmac_sha384_preparekey(&key, raw_key, raw_key_len);
-	hmac_sha384(&key, data, data_len, out);
+	struct hmac_sha384_ctx ctx;
 
-	memzero_explicit(&key, sizeof(key));
+	hmac_sha384_init_usingrawkey(&ctx, raw_key, raw_key_len);
+	hmac_sha384_update(&ctx, data, data_len);
+	hmac_sha384_final(&ctx, out);
 }
 EXPORT_SYMBOL_GPL(hmac_sha384_usingrawkey);
 
 void hmac_sha512_usingrawkey(const u8 *raw_key, size_t raw_key_len,
 			     const u8 *data, size_t data_len,
 			     u8 out[SHA512_DIGEST_SIZE])
 {
-	struct hmac_sha512_key key;
-
-	hmac_sha512_preparekey(&key, raw_key, raw_key_len);
-	hmac_sha512(&key, data, data_len, out);
+	struct hmac_sha512_ctx ctx;
 
-	memzero_explicit(&key, sizeof(key));
+	hmac_sha512_init_usingrawkey(&ctx, raw_key, raw_key_len);
+	hmac_sha512_update(&ctx, data, data_len);
+	hmac_sha512_final(&ctx, out);
 }
 EXPORT_SYMBOL_GPL(hmac_sha512_usingrawkey);
 
 #ifdef sha512_mod_init_arch
 static int __init sha512_mod_init(void)

base-commit: e14ada7ed2e1dda5161051be1d2131b606c8ab96
-- 
2.50.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] lib/crypto: sha2: Add hmac_sha*_init_usingrawkey()
  2025-07-11 21:58 [PATCH] lib/crypto: sha2: Add hmac_sha*_init_usingrawkey() Eric Biggers
@ 2025-07-14  5:24 ` Ard Biesheuvel
  0 siblings, 0 replies; 2+ messages in thread
From: Ard Biesheuvel @ 2025-07-14  5:24 UTC (permalink / raw)
  To: Eric Biggers; +Cc: linux-crypto, linux-kernel, Jason A . Donenfeld

On Sat, 12 Jul 2025 at 07:59, Eric Biggers <ebiggers@kernel.org> wrote:
>
> While the HMAC library functions support both incremental and one-shot
> computation and both prepared and raw keys, the combination of raw key
> + incremental was missing.  It turns out that several potential users of
> the HMAC library functions (tpm2-sessions.c, smb2transport.c,
> trusted_tpm1.c) want exactly that.
>
> Therefore, add the missing functions hmac_sha*_init_usingrawkey().
>
> Implement them in an optimized way that directly initializes the HMAC
> context without a separate key preparation step.
>
> Reimplement the one-shot raw key functions hmac_sha*_usingrawkey() on
> top of the new functions, which makes them a bit more efficient.
>
> Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  include/crypto/sha2.h | 60 +++++++++++++++++++++++++++++++++++++++++++
>  lib/crypto/sha256.c   | 53 ++++++++++++++++++++++++++------------
>  lib/crypto/sha512.c   | 55 +++++++++++++++++++++++++++------------
>  3 files changed, 134 insertions(+), 34 deletions(-)
>
> diff --git a/include/crypto/sha2.h b/include/crypto/sha2.h
> index e0a08f6addd00..15e461e568cca 100644
> --- a/include/crypto/sha2.h
> +++ b/include/crypto/sha2.h
> @@ -245,10 +245,25 @@ static inline void hmac_sha224_init(struct hmac_sha224_ctx *ctx,
>                                     const struct hmac_sha224_key *key)
>  {
>         __hmac_sha256_init(&ctx->ctx, &key->key);
>  }
>
> +/**
> + * hmac_sha224_init_usingrawkey() - Initialize an HMAC-SHA224 context for a new
> + *                                 message, using a raw key
> + * @ctx: (output) the HMAC context to initialize
> + * @raw_key: the raw HMAC-SHA224 key
> + * @raw_key_len: the key length in bytes.  All key lengths are supported.
> + *
> + * If you don't need incremental computation, consider hmac_sha224_usingrawkey()
> + * instead.
> + *
> + * Context: Any context.
> + */
> +void hmac_sha224_init_usingrawkey(struct hmac_sha224_ctx *ctx,
> +                                 const u8 *raw_key, size_t raw_key_len);
> +
>  /**
>   * hmac_sha224_update() - Update an HMAC-SHA224 context with message data
>   * @ctx: the HMAC context to update; must have been initialized
>   * @data: the message data
>   * @data_len: the data length in bytes
> @@ -403,10 +418,25 @@ static inline void hmac_sha256_init(struct hmac_sha256_ctx *ctx,
>                                     const struct hmac_sha256_key *key)
>  {
>         __hmac_sha256_init(&ctx->ctx, &key->key);
>  }
>
> +/**
> + * hmac_sha256_init_usingrawkey() - Initialize an HMAC-SHA256 context for a new
> + *                                 message, using a raw key
> + * @ctx: (output) the HMAC context to initialize
> + * @raw_key: the raw HMAC-SHA256 key
> + * @raw_key_len: the key length in bytes.  All key lengths are supported.
> + *
> + * If you don't need incremental computation, consider hmac_sha256_usingrawkey()
> + * instead.
> + *
> + * Context: Any context.
> + */
> +void hmac_sha256_init_usingrawkey(struct hmac_sha256_ctx *ctx,
> +                                 const u8 *raw_key, size_t raw_key_len);
> +
>  /**
>   * hmac_sha256_update() - Update an HMAC-SHA256 context with message data
>   * @ctx: the HMAC context to update; must have been initialized
>   * @data: the message data
>   * @data_len: the data length in bytes
> @@ -595,10 +625,25 @@ static inline void hmac_sha384_init(struct hmac_sha384_ctx *ctx,
>                                     const struct hmac_sha384_key *key)
>  {
>         __hmac_sha512_init(&ctx->ctx, &key->key);
>  }
>
> +/**
> + * hmac_sha384_init_usingrawkey() - Initialize an HMAC-SHA384 context for a new
> + *                                 message, using a raw key
> + * @ctx: (output) the HMAC context to initialize
> + * @raw_key: the raw HMAC-SHA384 key
> + * @raw_key_len: the key length in bytes.  All key lengths are supported.
> + *
> + * If you don't need incremental computation, consider hmac_sha384_usingrawkey()
> + * instead.
> + *
> + * Context: Any context.
> + */
> +void hmac_sha384_init_usingrawkey(struct hmac_sha384_ctx *ctx,
> +                                 const u8 *raw_key, size_t raw_key_len);
> +
>  /**
>   * hmac_sha384_update() - Update an HMAC-SHA384 context with message data
>   * @ctx: the HMAC context to update; must have been initialized
>   * @data: the message data
>   * @data_len: the data length in bytes
> @@ -753,10 +798,25 @@ static inline void hmac_sha512_init(struct hmac_sha512_ctx *ctx,
>                                     const struct hmac_sha512_key *key)
>  {
>         __hmac_sha512_init(&ctx->ctx, &key->key);
>  }
>
> +/**
> + * hmac_sha512_init_usingrawkey() - Initialize an HMAC-SHA512 context for a new
> + *                                 message, using a raw key
> + * @ctx: (output) the HMAC context to initialize
> + * @raw_key: the raw HMAC-SHA512 key
> + * @raw_key_len: the key length in bytes.  All key lengths are supported.
> + *
> + * If you don't need incremental computation, consider hmac_sha512_usingrawkey()
> + * instead.
> + *
> + * Context: Any context.
> + */
> +void hmac_sha512_init_usingrawkey(struct hmac_sha512_ctx *ctx,
> +                                 const u8 *raw_key, size_t raw_key_len);
> +
>  /**
>   * hmac_sha512_update() - Update an HMAC-SHA512 context with message data
>   * @ctx: the HMAC context to update; must have been initialized
>   * @data: the message data
>   * @data_len: the data length in bytes
> diff --git a/lib/crypto/sha256.c b/lib/crypto/sha256.c
> index 808438d4f4278..8fa15165d23e8 100644
> --- a/lib/crypto/sha256.c
> +++ b/lib/crypto/sha256.c
> @@ -261,11 +261,12 @@ void sha256(const u8 *data, size_t len, u8 out[SHA256_DIGEST_SIZE])
>  }
>  EXPORT_SYMBOL(sha256);
>
>  /* pre-boot environment (as indicated by __DISABLE_EXPORTS) doesn't need HMAC */
>  #ifndef __DISABLE_EXPORTS
> -static void __hmac_sha256_preparekey(struct __hmac_sha256_key *key,
> +static void __hmac_sha256_preparekey(struct sha256_block_state *istate,
> +                                    struct sha256_block_state *ostate,
>                                      const u8 *raw_key, size_t raw_key_len,
>                                      const struct sha256_block_state *iv)
>  {
>         union {
>                 u8 b[SHA256_BLOCK_SIZE];
> @@ -281,33 +282,35 @@ static void __hmac_sha256_preparekey(struct __hmac_sha256_key *key,
>                 memcpy(derived_key.b, raw_key, raw_key_len);
>         }
>
>         for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
>                 derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE);
> -       key->istate = *iv;
> -       sha256_blocks(&key->istate, derived_key.b, 1);
> +       *istate = *iv;
> +       sha256_blocks(istate, derived_key.b, 1);
>
>         for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
>                 derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^
>                                                 HMAC_IPAD_VALUE);
> -       key->ostate = *iv;
> -       sha256_blocks(&key->ostate, derived_key.b, 1);
> +       *ostate = *iv;
> +       sha256_blocks(ostate, derived_key.b, 1);
>
>         memzero_explicit(&derived_key, sizeof(derived_key));
>  }
>
>  void hmac_sha224_preparekey(struct hmac_sha224_key *key,
>                             const u8 *raw_key, size_t raw_key_len)
>  {
> -       __hmac_sha256_preparekey(&key->key, raw_key, raw_key_len, &sha224_iv);
> +       __hmac_sha256_preparekey(&key->key.istate, &key->key.ostate,
> +                                raw_key, raw_key_len, &sha224_iv);
>  }
>  EXPORT_SYMBOL_GPL(hmac_sha224_preparekey);
>
>  void hmac_sha256_preparekey(struct hmac_sha256_key *key,
>                             const u8 *raw_key, size_t raw_key_len)
>  {
> -       __hmac_sha256_preparekey(&key->key, raw_key, raw_key_len, &sha256_iv);
> +       __hmac_sha256_preparekey(&key->key.istate, &key->key.ostate,
> +                                raw_key, raw_key_len, &sha256_iv);
>  }
>  EXPORT_SYMBOL_GPL(hmac_sha256_preparekey);
>
>  void __hmac_sha256_init(struct __hmac_sha256_ctx *ctx,
>                         const struct __hmac_sha256_key *key)
> @@ -315,10 +318,28 @@ void __hmac_sha256_init(struct __hmac_sha256_ctx *ctx,
>         __sha256_init(&ctx->sha_ctx, &key->istate, SHA256_BLOCK_SIZE);
>         ctx->ostate = key->ostate;
>  }
>  EXPORT_SYMBOL_GPL(__hmac_sha256_init);
>
> +void hmac_sha224_init_usingrawkey(struct hmac_sha224_ctx *ctx,
> +                                 const u8 *raw_key, size_t raw_key_len)
> +{
> +       __hmac_sha256_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
> +                                raw_key, raw_key_len, &sha224_iv);
> +       ctx->ctx.sha_ctx.bytecount = SHA256_BLOCK_SIZE;
> +}
> +EXPORT_SYMBOL_GPL(hmac_sha224_init_usingrawkey);
> +
> +void hmac_sha256_init_usingrawkey(struct hmac_sha256_ctx *ctx,
> +                                 const u8 *raw_key, size_t raw_key_len)
> +{
> +       __hmac_sha256_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
> +                                raw_key, raw_key_len, &sha256_iv);
> +       ctx->ctx.sha_ctx.bytecount = SHA256_BLOCK_SIZE;
> +}
> +EXPORT_SYMBOL_GPL(hmac_sha256_init_usingrawkey);
> +
>  static void __hmac_sha256_final(struct __hmac_sha256_ctx *ctx,
>                                 u8 *out, size_t digest_size)
>  {
>         /* Generate the padded input for the outer hash in ctx->sha_ctx.buf. */
>         __sha256_final(&ctx->sha_ctx, ctx->sha_ctx.buf, digest_size);
> @@ -374,29 +395,27 @@ EXPORT_SYMBOL_GPL(hmac_sha256);
>
>  void hmac_sha224_usingrawkey(const u8 *raw_key, size_t raw_key_len,
>                              const u8 *data, size_t data_len,
>                              u8 out[SHA224_DIGEST_SIZE])
>  {
> -       struct hmac_sha224_key key;
> -
> -       hmac_sha224_preparekey(&key, raw_key, raw_key_len);
> -       hmac_sha224(&key, data, data_len, out);
> +       struct hmac_sha224_ctx ctx;
>
> -       memzero_explicit(&key, sizeof(key));
> +       hmac_sha224_init_usingrawkey(&ctx, raw_key, raw_key_len);
> +       hmac_sha224_update(&ctx, data, data_len);
> +       hmac_sha224_final(&ctx, out);
>  }
>  EXPORT_SYMBOL_GPL(hmac_sha224_usingrawkey);
>
>  void hmac_sha256_usingrawkey(const u8 *raw_key, size_t raw_key_len,
>                              const u8 *data, size_t data_len,
>                              u8 out[SHA256_DIGEST_SIZE])
>  {
> -       struct hmac_sha256_key key;
> -
> -       hmac_sha256_preparekey(&key, raw_key, raw_key_len);
> -       hmac_sha256(&key, data, data_len, out);
> +       struct hmac_sha256_ctx ctx;
>
> -       memzero_explicit(&key, sizeof(key));
> +       hmac_sha256_init_usingrawkey(&ctx, raw_key, raw_key_len);
> +       hmac_sha256_update(&ctx, data, data_len);
> +       hmac_sha256_final(&ctx, out);
>  }
>  EXPORT_SYMBOL_GPL(hmac_sha256_usingrawkey);
>  #endif /* !__DISABLE_EXPORTS */
>
>  #ifdef sha256_mod_init_arch
> diff --git a/lib/crypto/sha512.c b/lib/crypto/sha512.c
> index d514721491ca0..d8062188be98a 100644
> --- a/lib/crypto/sha512.c
> +++ b/lib/crypto/sha512.c
> @@ -247,11 +247,12 @@ void sha512(const u8 *data, size_t len, u8 out[SHA512_DIGEST_SIZE])
>         sha512_update(&ctx, data, len);
>         sha512_final(&ctx, out);
>  }
>  EXPORT_SYMBOL_GPL(sha512);
>
> -static void __hmac_sha512_preparekey(struct __hmac_sha512_key *key,
> +static void __hmac_sha512_preparekey(struct sha512_block_state *istate,
> +                                    struct sha512_block_state *ostate,
>                                      const u8 *raw_key, size_t raw_key_len,
>                                      const struct sha512_block_state *iv)
>  {
>         union {
>                 u8 b[SHA512_BLOCK_SIZE];
> @@ -267,33 +268,35 @@ static void __hmac_sha512_preparekey(struct __hmac_sha512_key *key,
>                 memcpy(derived_key.b, raw_key, raw_key_len);
>         }
>
>         for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
>                 derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE);
> -       key->istate = *iv;
> -       sha512_blocks(&key->istate, derived_key.b, 1);
> +       *istate = *iv;
> +       sha512_blocks(istate, derived_key.b, 1);
>
>         for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
>                 derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^
>                                                 HMAC_IPAD_VALUE);
> -       key->ostate = *iv;
> -       sha512_blocks(&key->ostate, derived_key.b, 1);
> +       *ostate = *iv;
> +       sha512_blocks(ostate, derived_key.b, 1);
>
>         memzero_explicit(&derived_key, sizeof(derived_key));
>  }
>
>  void hmac_sha384_preparekey(struct hmac_sha384_key *key,
>                             const u8 *raw_key, size_t raw_key_len)
>  {
> -       __hmac_sha512_preparekey(&key->key, raw_key, raw_key_len, &sha384_iv);
> +       __hmac_sha512_preparekey(&key->key.istate, &key->key.ostate,
> +                                raw_key, raw_key_len, &sha384_iv);
>  }
>  EXPORT_SYMBOL_GPL(hmac_sha384_preparekey);
>
>  void hmac_sha512_preparekey(struct hmac_sha512_key *key,
>                             const u8 *raw_key, size_t raw_key_len)
>  {
> -       __hmac_sha512_preparekey(&key->key, raw_key, raw_key_len, &sha512_iv);
> +       __hmac_sha512_preparekey(&key->key.istate, &key->key.ostate,
> +                                raw_key, raw_key_len, &sha512_iv);
>  }
>  EXPORT_SYMBOL_GPL(hmac_sha512_preparekey);
>
>  void __hmac_sha512_init(struct __hmac_sha512_ctx *ctx,
>                         const struct __hmac_sha512_key *key)
> @@ -301,10 +304,30 @@ void __hmac_sha512_init(struct __hmac_sha512_ctx *ctx,
>         __sha512_init(&ctx->sha_ctx, &key->istate, SHA512_BLOCK_SIZE);
>         ctx->ostate = key->ostate;
>  }
>  EXPORT_SYMBOL_GPL(__hmac_sha512_init);
>
> +void hmac_sha384_init_usingrawkey(struct hmac_sha384_ctx *ctx,
> +                                 const u8 *raw_key, size_t raw_key_len)
> +{
> +       __hmac_sha512_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
> +                                raw_key, raw_key_len, &sha384_iv);
> +       ctx->ctx.sha_ctx.bytecount_lo = SHA512_BLOCK_SIZE;
> +       ctx->ctx.sha_ctx.bytecount_hi = 0;
> +}
> +EXPORT_SYMBOL_GPL(hmac_sha384_init_usingrawkey);
> +
> +void hmac_sha512_init_usingrawkey(struct hmac_sha512_ctx *ctx,
> +                                 const u8 *raw_key, size_t raw_key_len)
> +{
> +       __hmac_sha512_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
> +                                raw_key, raw_key_len, &sha512_iv);
> +       ctx->ctx.sha_ctx.bytecount_lo = SHA512_BLOCK_SIZE;
> +       ctx->ctx.sha_ctx.bytecount_hi = 0;
> +}
> +EXPORT_SYMBOL_GPL(hmac_sha512_init_usingrawkey);
> +
>  static void __hmac_sha512_final(struct __hmac_sha512_ctx *ctx,
>                                 u8 *out, size_t digest_size)
>  {
>         /* Generate the padded input for the outer hash in ctx->sha_ctx.buf. */
>         __sha512_final(&ctx->sha_ctx, ctx->sha_ctx.buf, digest_size);
> @@ -360,29 +383,27 @@ EXPORT_SYMBOL_GPL(hmac_sha512);
>
>  void hmac_sha384_usingrawkey(const u8 *raw_key, size_t raw_key_len,
>                              const u8 *data, size_t data_len,
>                              u8 out[SHA384_DIGEST_SIZE])
>  {
> -       struct hmac_sha384_key key;
> -
> -       hmac_sha384_preparekey(&key, raw_key, raw_key_len);
> -       hmac_sha384(&key, data, data_len, out);
> +       struct hmac_sha384_ctx ctx;
>
> -       memzero_explicit(&key, sizeof(key));
> +       hmac_sha384_init_usingrawkey(&ctx, raw_key, raw_key_len);
> +       hmac_sha384_update(&ctx, data, data_len);
> +       hmac_sha384_final(&ctx, out);
>  }
>  EXPORT_SYMBOL_GPL(hmac_sha384_usingrawkey);
>
>  void hmac_sha512_usingrawkey(const u8 *raw_key, size_t raw_key_len,
>                              const u8 *data, size_t data_len,
>                              u8 out[SHA512_DIGEST_SIZE])
>  {
> -       struct hmac_sha512_key key;
> -
> -       hmac_sha512_preparekey(&key, raw_key, raw_key_len);
> -       hmac_sha512(&key, data, data_len, out);
> +       struct hmac_sha512_ctx ctx;
>
> -       memzero_explicit(&key, sizeof(key));
> +       hmac_sha512_init_usingrawkey(&ctx, raw_key, raw_key_len);
> +       hmac_sha512_update(&ctx, data, data_len);
> +       hmac_sha512_final(&ctx, out);
>  }
>  EXPORT_SYMBOL_GPL(hmac_sha512_usingrawkey);
>
>  #ifdef sha512_mod_init_arch
>  static int __init sha512_mod_init(void)
>
> base-commit: e14ada7ed2e1dda5161051be1d2131b606c8ab96
> --
> 2.50.1
>

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2025-07-11 21:58 [PATCH] lib/crypto: sha2: Add hmac_sha*_init_usingrawkey() Eric Biggers
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