[rng] Allow HMAC_DRBG to use multiple underlying hash algorithms

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 73 insertions, 59 deletions

diff --git a/src/crypto/hmac_drbg.c b/src/crypto/hmac_drbg.c
index 9e70e4e6..3f56e1b7 100644
--- a/src/crypto/hmac_drbg.c
+++ b/src/crypto/hmac_drbg.c
@@ -46,6 +46,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 /**
  * Update the HMAC_DRBG key
  *
+ * @v hash		Underlying hash algorithm
  * @v state		HMAC_DRBG internal state
  * @v data		Provided data
  * @v len		Length of provided data
@@ -57,40 +58,40 @@ FILE_LICENCE ( GPL2_OR_LATER );
  *
  * as used by hmac_drbg_update()
  */
-static void hmac_drbg_update_key ( struct hmac_drbg_state *state,
+static void hmac_drbg_update_key ( struct digest_algorithm *hash,
+				   struct hmac_drbg_state *state,
 				   const void *data, size_t len,
 				   const uint8_t single ) {
-	uint8_t context[HMAC_DRBG_CTX_SIZE];
-	size_t key_len = sizeof ( state->key );
+	uint8_t context[ hash->ctxsize ];
+	size_t out_len = hash->digestsize;
 
-	DBGC ( state, "HMAC_DRBG %p provided data :\n", state );
+	DBGC ( state, "HMAC_DRBG_%s %p provided data :\n", hash->name, state );
 	DBGC_HDA ( state, 0, data, len );
 
 	/* Sanity checks */
+	assert ( hash != NULL );
 	assert ( state != NULL );
 	assert ( ( data != NULL ) || ( len == 0 ) );
 	assert ( ( single == 0x00 ) || ( single == 0x01 ) );
 
 	/* K = HMAC ( K, V || single || provided_data ) */
-	hmac_init ( &hmac_drbg_algorithm, context, state->key, &key_len );
-	assert ( key_len == sizeof ( state->key ) );
-	hmac_update ( &hmac_drbg_algorithm, context,
-		      state->value, sizeof ( state->value ) );
-	hmac_update ( &hmac_drbg_algorithm, context,
-		      &single, sizeof ( single ) );
-	hmac_update ( &hmac_drbg_algorithm, context, data, len );
-	hmac_final ( &hmac_drbg_algorithm, context, state->key, &key_len,
-		     state->key );
-	assert ( key_len == sizeof ( state->key ) );
-
-	DBGC ( state, "HMAC_DRBG %p K = HMAC ( K, V || %#02x || "
-	       "provided_data ) :\n", state, single );
-	DBGC_HDA ( state, 0, state->key, sizeof ( state->key ) );
+	hmac_init ( hash, context, state->key, &out_len );
+	assert ( out_len == hash->digestsize );
+	hmac_update ( hash, context, state->value, out_len );
+	hmac_update ( hash, context, &single, sizeof ( single ) );
+	hmac_update ( hash, context, data, len );
+	hmac_final ( hash, context, state->key, &out_len, state->key );
+	assert ( out_len == hash->digestsize );
+
+	DBGC ( state, "HMAC_DRBG_%s %p K = HMAC ( K, V || %#02x || "
+	       "provided_data ) :\n", hash->name, state, single );
+	DBGC_HDA ( state, 0, state->key, out_len );
 }
 
 /**
  * Update the HMAC_DRBG value
  *
+ * @v hash		Underlying hash algorithm
  * @v state		HMAC_DRBG internal state
  * @v data		Provided data
  * @v len		Length of provided data
@@ -102,29 +103,31 @@ static void hmac_drbg_update_key ( struct hmac_drbg_state *state,
  *
  * as used by hmac_drbg_update() and hmac_drbg_generate()
  */
-static void hmac_drbg_update_value ( struct hmac_drbg_state *state ) {
-	uint8_t context[HMAC_DRBG_CTX_SIZE];
-	size_t key_len = sizeof ( state->key );
+static void hmac_drbg_update_value ( struct digest_algorithm *hash,
+				     struct hmac_drbg_state *state ) {
+	uint8_t context[ hash->ctxsize ];
+	size_t out_len = hash->digestsize;
 
 	/* Sanity checks */
+	assert ( hash != NULL );
 	assert ( state != NULL );
 
 	/* V = HMAC ( K, V ) */
-	hmac_init ( &hmac_drbg_algorithm, context, state->key, &key_len );
-	assert ( key_len == sizeof ( state->key ) );
-	hmac_update ( &hmac_drbg_algorithm, context,
-		      state->value, sizeof ( state->value ) );
-	hmac_final ( &hmac_drbg_algorithm, context, state->key, &key_len,
-		     state->value );
-	assert ( key_len == sizeof ( state->key ) );
-
-	DBGC ( state, "HMAC_DRBG %p V = HMAC ( K, V ) :\n", state );
-	DBGC_HDA ( state, 0, state->value, sizeof ( state->value ) );
+	hmac_init ( hash, context, state->key, &out_len );
+	assert ( out_len == hash->digestsize );
+	hmac_update ( hash, context, state->value, out_len );
+	hmac_final ( hash, context, state->key, &out_len, state->value );
+	assert ( out_len == hash->digestsize );
+
+	DBGC ( state, "HMAC_DRBG_%s %p V = HMAC ( K, V ) :\n",
+	       hash->name, state );
+	DBGC_HDA ( state, 0, state->value, out_len );
 }
 
 /**
  * Update HMAC_DRBG internal state
  *
+ * @v hash		Underlying hash algorithm
  * @v state		HMAC_DRBG internal state
  * @v data		Provided data
  * @v len		Length of provided data
@@ -135,30 +138,32 @@ static void hmac_drbg_update_value ( struct hmac_drbg_state *state ) {
  * The key and value are updated in-place within the HMAC_DRBG
  * internal state.
  */
-static void hmac_drbg_update ( struct hmac_drbg_state *state,
+static void hmac_drbg_update ( struct digest_algorithm *hash,
+			       struct hmac_drbg_state *state,
 			       const void *data, size_t len ) {
 
-	DBGC ( state, "HMAC_DRBG %p update\n", state );
+	DBGC ( state, "HMAC_DRBG_%s %p update\n", hash->name, state );
 
 	/* Sanity checks */
+	assert ( hash != NULL );
 	assert ( state != NULL );
 	assert ( ( data != NULL ) || ( len == 0 ) );
 
 	/* 1.  K = HMAC ( K, V || 0x00 || provided_data ) */
-	hmac_drbg_update_key ( state, data, len, 0x00 );
+	hmac_drbg_update_key ( hash, state, data, len, 0x00 );
 
 	/* 2.  V = HMAC ( K, V ) */
-	hmac_drbg_update_value ( state );
+	hmac_drbg_update_value ( hash, state );
 
 	/* 3.  If ( provided_data = Null ), then return K and V */
 	if ( ! len )
 		return;
 
 	/* 4.  K = HMAC ( K, V || 0x01 || provided_data ) */
-	hmac_drbg_update_key ( state, data, len, 0x01 );
+	hmac_drbg_update_key ( hash, state, data, len, 0x01 );
 
 	/* 5.  V = HMAC ( K, V ) */
-	hmac_drbg_update_value ( state );
+	hmac_drbg_update_value ( hash, state );
 
 	/* 6.  Return K and V */
 }
@@ -166,6 +171,7 @@ static void hmac_drbg_update ( struct hmac_drbg_state *state,
 /**
  * Instantiate HMAC_DRBG
  *
+ * @v hash		Underlying hash algorithm
  * @v state		HMAC_DRBG internal state to be initialised
  * @v entropy		Entropy input
  * @v entropy_len	Length of entropy input
@@ -184,17 +190,18 @@ static void hmac_drbg_update ( struct hmac_drbg_state *state,
  * The key, value and reseed counter are updated in-place within the
  * HMAC_DRBG internal state.
  */
-void hmac_drbg_instantiate ( struct hmac_drbg_state *state,
+void hmac_drbg_instantiate ( struct digest_algorithm *hash,
+			     struct hmac_drbg_state *state,
 			     const void *entropy, size_t entropy_len,
 			     const void *personal, size_t personal_len ){
+	size_t out_len = hash->digestsize;
 
-	DBGC ( state, "HMAC_DRBG %p instantiate\n", state );
+	DBGC ( state, "HMAC_DRBG_%s %p instantiate\n", hash->name, state );
 
 	/* Sanity checks */
+	assert ( hash != NULL );
 	assert ( state != NULL );
 	assert ( entropy != NULL );
-	assert ( ( 8 * entropy_len ) >=
-		 ( 3 * HMAC_DRBG_SECURITY_STRENGTH / 2 ) );
 	assert ( ( personal != NULL ) || ( personal_len == 0 ) );
 
 	/* 1.  seed_material = entropy_input || nonce ||
@@ -202,23 +209,24 @@ void hmac_drbg_instantiate ( struct hmac_drbg_state *state,
 	 */
 
 	/* 2.  Key = 0x00 00..00 */
-	memset ( state->key, 0x00, sizeof ( state->key ) );
+	memset ( state->key, 0x00, out_len );
 
 	/* 3.  V = 0x01 01...01 */
-	memset ( state->value, 0x01, sizeof ( state->value ) );
+	memset ( state->value, 0x01, out_len );
 
 	/* 4.  ( Key, V ) = HMAC_DBRG_Update ( seed_material, Key, V )
 	 * 5.  reseed_counter = 1
 	 * 6.  Return V, Key and reseed_counter as the
 	 *     initial_working_state
 	 */
-	hmac_drbg_reseed ( state, entropy, entropy_len,
+	hmac_drbg_reseed ( hash, state, entropy, entropy_len,
 			   personal, personal_len );
 }
 
 /**
  * Reseed HMAC_DRBG
  *
+ * @v hash		Underlying hash algorithm
  * @v state		HMAC_DRBG internal state
  * @v entropy		Entropy input
  * @v entropy_len	Length of entropy input
@@ -231,27 +239,29 @@ void hmac_drbg_instantiate ( struct hmac_drbg_state *state,
  * The key, value and reseed counter are updated in-place within the
  * HMAC_DRBG internal state.
  */
-void hmac_drbg_reseed ( struct hmac_drbg_state *state,
+void hmac_drbg_reseed ( struct digest_algorithm *hash,
+			struct hmac_drbg_state *state,
 			const void *entropy, size_t entropy_len,
 			const void *additional, size_t additional_len ) {
 	uint8_t seed_material[ entropy_len + additional_len ];
 
-	DBGC ( state, "HMAC_DRBG %p (re)seed\n", state );
+	DBGC ( state, "HMAC_DRBG_%s %p (re)seed\n", hash->name, state );
 
 	/* Sanity checks */
+	assert ( hash != NULL );
 	assert ( state != NULL );
 	assert ( entropy != NULL );
-	assert ( ( 8 * entropy_len ) >= HMAC_DRBG_SECURITY_STRENGTH );
 	assert ( ( additional != NULL ) || ( additional_len == 0 ) );
 
 	/* 1.  seed_material = entropy_input || additional_input */
 	memcpy ( seed_material, entropy, entropy_len );
 	memcpy ( ( seed_material + entropy_len ), additional, additional_len );
-	DBGC ( state, "HMAC_DRBG %p seed material :\n", state );
+	DBGC ( state, "HMAC_DRBG_%s %p seed material :\n", hash->name, state );
 	DBGC_HDA ( state, 0, seed_material, sizeof ( seed_material ) );
 
 	/* 2.  ( Key, V ) = HMAC_DBRG_Update ( seed_material, Key, V ) */
-	hmac_drbg_update ( state, seed_material, sizeof ( seed_material ) );
+	hmac_drbg_update ( hash, state, seed_material,
+			   sizeof ( seed_material ) );
 
 	/* 3.  reseed_counter = 1 */
 	state->reseed_counter = 1;
@@ -262,6 +272,7 @@ void hmac_drbg_reseed ( struct hmac_drbg_state *state,
 /**
  * Generate pseudorandom bits using HMAC_DRBG
  *
+ * @v hash		Underlying hash algorithm
  * @v state		HMAC_DRBG internal state
  * @v additional	Additional input
  * @v additional_len	Length of additional input
@@ -279,16 +290,19 @@ void hmac_drbg_reseed ( struct hmac_drbg_state *state,
  *
  * Note that the only permitted error is "reseed required".
  */
-int hmac_drbg_generate ( struct hmac_drbg_state *state,
+int hmac_drbg_generate ( struct digest_algorithm *hash,
+			 struct hmac_drbg_state *state,
 			 const void *additional, size_t additional_len,
 			 void *data, size_t len ) {
+	size_t out_len = hash->digestsize;
 	void *orig_data = data;
 	size_t orig_len = len;
 	size_t frag_len;
 
-	DBGC ( state, "HMAC_DRBG %p generate\n", state );
+	DBGC ( state, "HMAC_DRBG_%s %p generate\n", hash->name, state );
 
 	/* Sanity checks */
+	assert ( hash != NULL );
 	assert ( state != NULL );
 	assert ( data != NULL );
 	assert ( ( additional != NULL ) || ( additional_len == 0 ) );
@@ -297,8 +311,8 @@ int hmac_drbg_generate ( struct hmac_drbg_state *state,
 	 *     indication that a reseed is required
 	 */
 	if ( state->reseed_counter > HMAC_DRBG_RESEED_INTERVAL ) {
-		DBGC ( state, "HMAC_DRBG %p reseed interval exceeded\n",
-		       state );
+		DBGC ( state, "HMAC_DRBG_%s %p reseed interval exceeded\n",
+		       hash->name, state );
 		return -ESTALE;
 	}
 
@@ -306,7 +320,7 @@ int hmac_drbg_generate ( struct hmac_drbg_state *state,
 	 *     ( Key, V ) = HMAC_DRBG_Update ( additional_input, Key, V )
 	 */
 	if ( additional_len )
-		hmac_drbg_update ( state, additional, additional_len );
+		hmac_drbg_update ( hash, state, additional, additional_len );
 
 	/* 3.  temp = Null
 	 * 4.  While ( len ( temp ) < requested_number_of_bits ) do:
@@ -314,27 +328,27 @@ int hmac_drbg_generate ( struct hmac_drbg_state *state,
 	while ( len ) {
 
 		/* 4.1  V = HMAC ( Key, V ) */
-		hmac_drbg_update_value ( state );
+		hmac_drbg_update_value ( hash, state );
 
 		/* 4.2.  temp = temp || V
 		 * 5.    returned_bits = Leftmost requested_number_of_bits
 		 *       of temp
 		 */
 		frag_len = len;
-		if ( frag_len > sizeof ( state->value ) )
-			frag_len = sizeof ( state->value );
+		if ( frag_len > out_len )
+			frag_len = out_len;
 		memcpy ( data, state->value, frag_len );
 		data += frag_len;
 		len -= frag_len;
 	}
 
 	/* 6.  ( Key, V ) = HMAC_DRBG_Update ( additional_input, Key, V ) */
-	hmac_drbg_update ( state, additional, additional_len );
+	hmac_drbg_update ( hash, state, additional, additional_len );
 
 	/* 7.  reseed_counter = reseed_counter + 1 */
 	state->reseed_counter++;
 
-	DBGC ( state, "HMAC_DRBG %p generated :\n", state );
+	DBGC ( state, "HMAC_DRBG_%s %p generated :\n", hash->name, state );
 	DBGC_HDA ( state, 0, orig_data, orig_len );
 
 	/* 8.  Return SUCCESS, returned_bits, and the new values of