7 files changed, 54 insertions, 53 deletions

diff --git a/src/lib/libcrypto/mlkem/mlkem768.c b/src/lib/libcrypto/mlkem/mlkem768.c
index b20545defc..82adea7b42 100644
--- a/src/lib/libcrypto/mlkem/mlkem768.c
+++ b/src/lib/libcrypto/mlkem/mlkem768.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mlkem768.c,v 1.10 2025/05/19 07:40:17 beck Exp $ */
+/* $OpenBSD: mlkem768.c,v 1.11 2025/05/19 07:53:00 beck Exp $ */
 /*
  * Copyright (c) 2024, Google Inc.
  * Copyright (c) 2024, Bob Beck <beck@obtuse.com>
@@ -611,6 +611,19 @@ vector_encode(uint8_t *out, const vector *a, int bits)
         }
 }
 
+/* Encodes an entire vector as above, but adding it to a CBB */
+static int
+vector_encode_cbb(CBB *cbb, const vector *a, int bits)
+{
+        uint8_t *encoded_vector;
+
+        if (!CBB_add_space(cbb, &encoded_vector, kEncodedVectorSize))
+                return 0;
+        vector_encode(encoded_vector, a, bits);
+
+        return 1;
+}
+
 /*
  * scalar_decode parses |DEGREE * bits| bits from |in| into |DEGREE| values in
  * |out|. It returns one on success and zero if any parsed value is >=
@@ -850,16 +863,9 @@ LCRYPTO_ALIAS(MLKEM768_private_key_from_seed);
 static int
 mlkem_marshal_public_key(CBB *out, const struct public_key *pub)
 {
-        uint8_t *vector_output;
-
-        if (!CBB_add_space(out, &vector_output, kEncodedVectorSize)) {
+        if (!vector_encode_cbb(out, &pub->t, kLog2Prime))
                 return 0;
-        }
-        vector_encode(vector_output, &pub->t, kLog2Prime);
-        if (!CBB_add_bytes(out, pub->rho, sizeof(pub->rho))) {
-                return 0;
-        }
-        return 1;
+        return CBB_add_bytes(out, pub->rho, sizeof(pub->rho));
 }
 
 int
@@ -1117,27 +1123,37 @@ MLKEM768_parse_public_key(struct MLKEM768_public_key *public_key,
 LCRYPTO_ALIAS(MLKEM768_parse_public_key);
 
 int
-MLKEM768_marshal_private_key(CBB *out,
-    const struct MLKEM768_private_key *private_key)
+MLKEM768_marshal_private_key(const struct MLKEM768_private_key *private_key,
+    uint8_t **out_private_key, size_t *out_private_key_len)
 {
         const struct private_key *const priv = private_key_768_from_external(
             private_key);
-        uint8_t *s_output;
+        CBB cbb;
+        int ret = 0;
 
-        if (!CBB_add_space(out, &s_output, kEncodedVectorSize)) {
-                return 0;
-        }
-        vector_encode(s_output, &priv->s, kLog2Prime);
-        if (!mlkem_marshal_public_key(out, &priv->pub))
-                return 0;
-        if (!CBB_add_bytes(out, priv->pub.public_key_hash,
+        if (!CBB_init(&cbb, MLKEM768_PRIVATE_KEY_BYTES))
+                goto err;
+
+        if (!vector_encode_cbb(&cbb, &priv->s, kLog2Prime))
+                goto err;
+        if (!mlkem_marshal_public_key(&cbb, &priv->pub))
+                goto err;
+        if (!CBB_add_bytes(&cbb, priv->pub.public_key_hash,
             sizeof(priv->pub.public_key_hash)))
-                return 0;
-        if (!CBB_add_bytes(out, priv->fo_failure_secret,
+                goto err;
+        if (!CBB_add_bytes(&cbb, priv->fo_failure_secret,
             sizeof(priv->fo_failure_secret)))
-                return 0;
+                goto err;
 
-        return 1;
+        if (!CBB_finish(&cbb, out_private_key, out_private_key_len))
+                goto err;
+
+        ret = 1;
+
+ err:
+        CBB_cleanup(&cbb);
+
+        return ret;
 }
 
 int
diff --git a/src/lib/libcrypto/mlkem/mlkem_internal.h b/src/lib/libcrypto/mlkem/mlkem_internal.h
index 7a51197c36..aed051e980 100644
--- a/src/lib/libcrypto/mlkem/mlkem_internal.h
+++ b/src/lib/libcrypto/mlkem/mlkem_internal.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: mlkem_internal.h,v 1.5 2025/05/19 06:47:40 beck Exp $ */
+/*      $OpenBSD: mlkem_internal.h,v 1.6 2025/05/19 07:53:00 beck Exp $ */
 /*
  * Copyright (c) 2023, Google Inc.
  *
@@ -57,8 +57,8 @@ int MLKEM768_generate_key_external_entropy(
  * format for ML-KEM private keys. It returns one on success or zero on
  * allocation error.
  */
-int MLKEM768_marshal_private_key(CBB *out,
-    const struct MLKEM768_private_key *private_key);
+int MLKEM768_marshal_private_key(const struct MLKEM768_private_key *private_key,
+    uint8_t **out_private_key, size_t *out_private_key_len);
 
 /*
  * MLKEM_encap_external_entropy behaves like |MLKEM_encap|, but uses
diff --git a/src/regress/lib/libcrypto/mlkem/mlkem_iteration_tests.c b/src/regress/lib/libcrypto/mlkem/mlkem_iteration_tests.c
index a8495f55e3..e0fd9ca241 100644
--- a/src/regress/lib/libcrypto/mlkem/mlkem_iteration_tests.c
+++ b/src/regress/lib/libcrypto/mlkem/mlkem_iteration_tests.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: mlkem_iteration_tests.c,v 1.3 2025/05/19 06:47:40 beck Exp $ */
+/*      $OpenBSD: mlkem_iteration_tests.c,v 1.4 2025/05/19 07:53:00 beck Exp $ */
 /*
  * Copyright (c) 2024 Google Inc.
  * Copyright (c) 2024 Bob Beck <beck@obtuse.com>
@@ -185,7 +185,7 @@ main(void)
                 .priv = &priv768,
                 .pub = &pub768,
                 .encap_external_entropy = mlkem768_encap_external_entropy,
-                .encode_private_key = mlkem768_encode_private_key,
+                .encode_private_key = mlkem768_marshal_private_key,
                 .generate_key_external_entropy =
                     mlkem768_generate_key_external_entropy,
                 .public_from_private = mlkem768_public_from_private,
diff --git a/src/regress/lib/libcrypto/mlkem/mlkem_tests.c b/src/regress/lib/libcrypto/mlkem/mlkem_tests.c
index a4e7208c76..84b71aebb0 100644
--- a/src/regress/lib/libcrypto/mlkem/mlkem_tests.c
+++ b/src/regress/lib/libcrypto/mlkem/mlkem_tests.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: mlkem_tests.c,v 1.4 2025/05/19 06:47:40 beck Exp $ */
+/*      $OpenBSD: mlkem_tests.c,v 1.5 2025/05/19 07:53:00 beck Exp $ */
 /*
  * Copyright (c) 2024 Google Inc.
  * Copyright (c) 2024 Theo Buehler <tb@openbsd.org>
@@ -662,7 +662,7 @@ mlkem_keygen_tests(const char *fn, size_t size, enum test_type test_type)
                 .generate_key_external_entropy =
                     mlkem768_generate_key_external_entropy,
                 .encode_private_key =
-                    mlkem768_encode_private_key,
+                    mlkem768_marshal_private_key,
         };
         struct MLKEM1024_private_key private_key1024;
         uint8_t encoded_public_key1024[MLKEM1024_PUBLIC_KEY_BYTES];
diff --git a/src/regress/lib/libcrypto/mlkem/mlkem_tests_util.c b/src/regress/lib/libcrypto/mlkem/mlkem_tests_util.c
index 8677713c8e..5ec8c08585 100644
--- a/src/regress/lib/libcrypto/mlkem/mlkem_tests_util.c
+++ b/src/regress/lib/libcrypto/mlkem/mlkem_tests_util.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: mlkem_tests_util.c,v 1.6 2025/05/19 06:47:40 beck Exp $ */
+/*      $OpenBSD: mlkem_tests_util.c,v 1.7 2025/05/19 07:53:00 beck Exp $ */
 /*
  * Copyright (c) 2024 Google Inc.
  * Copyright (c) 2024 Bob Beck <beck@obtuse.com>
@@ -61,25 +61,10 @@ compare_data(const uint8_t *want, const uint8_t *got, size_t len, const char *ms
 }
 
 int
-mlkem768_encode_private_key(const void *private_key, uint8_t **out_buf,
+mlkem768_marshal_private_key(const void *private_key, uint8_t **out_buf,
     size_t *out_len)
 {
-        CBB cbb;
-        int ret = 0;
-
-        if (!CBB_init(&cbb, MLKEM768_PUBLIC_KEY_BYTES))
-                goto err;
-        if (!MLKEM768_marshal_private_key(&cbb, private_key))
-                goto err;
-        if (!CBB_finish(&cbb, out_buf, out_len))
-                goto err;
-
-        ret = 1;
-
- err:
-        CBB_cleanup(&cbb);
-
-        return ret;
+        return MLKEM768_marshal_private_key(private_key, out_buf, out_len);
 }
 
 int
diff --git a/src/regress/lib/libcrypto/mlkem/mlkem_tests_util.h b/src/regress/lib/libcrypto/mlkem/mlkem_tests_util.h
index a3b255082f..5c2c400ea5 100644
--- a/src/regress/lib/libcrypto/mlkem/mlkem_tests_util.h
+++ b/src/regress/lib/libcrypto/mlkem/mlkem_tests_util.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: mlkem_tests_util.h,v 1.5 2025/05/19 06:47:40 beck Exp $ */
+/*      $OpenBSD: mlkem_tests_util.h,v 1.6 2025/05/19 07:53:00 beck Exp $ */
 /*
  * Copyright (c) 2024 Bob Beck <beck@obtuse.com>
  * Copyright (c) 2024 Theo Buehler <tb@openbsd.org>
@@ -30,7 +30,7 @@
 int compare_data(const uint8_t *want, const uint8_t *got, size_t len,
     const char *msg);
 
-int mlkem768_encode_private_key(const void *priv, uint8_t **out_buf,
+int mlkem768_marshal_private_key(const void *priv, uint8_t **out_buf,
     size_t *out_len);
 int mlkem768_marshal_public_key(const void *pub, uint8_t **out_buf,
     size_t *out_len);
diff --git a/src/regress/lib/libcrypto/mlkem/mlkem_unittest.c b/src/regress/lib/libcrypto/mlkem/mlkem_unittest.c
index a1adc88569..ce1e797904 100644
--- a/src/regress/lib/libcrypto/mlkem/mlkem_unittest.c
+++ b/src/regress/lib/libcrypto/mlkem/mlkem_unittest.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: mlkem_unittest.c,v 1.8 2025/05/19 06:47:40 beck Exp $ */
+/*      $OpenBSD: mlkem_unittest.c,v 1.9 2025/05/19 07:53:00 beck Exp $ */
 /*
  * Copyright (c) 2024 Google Inc.
  * Copyright (c) 2024 Bob Beck <beck@obtuse.com>
@@ -205,7 +205,7 @@ mlkem768_unittest(void)
                 .generate_key = mlkem768_generate_key,
                 .parse_private_key = mlkem768_parse_private_key,
                 .parse_public_key = mlkem768_parse_public_key,
-                .encode_private_key = mlkem768_encode_private_key,
+                .encode_private_key = mlkem768_marshal_private_key,
                 .marshal_public_key = mlkem768_marshal_public_key,
                 .public_from_private = mlkem768_public_from_private,
         };