CTASSERT that internal pub/priv keys match the sizes exposed in mlkem.h

This will need reworking (especially deduplicating) anyway, but it doesn't
hurt now.

From Kenjiro Nakayama

2 files changed, 10 insertions, 2 deletions

diff --git a/src/lib/libcrypto/mlkem/mlkem1024.c b/src/lib/libcrypto/mlkem/mlkem1024.c
index f6fccdf6a8..ce6f26e66c 100644
--- a/src/lib/libcrypto/mlkem/mlkem1024.c
+++ b/src/lib/libcrypto/mlkem/mlkem1024.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mlkem1024.c,v 1.6 2025/01/03 08:19:24 tb Exp $ */
+/* $OpenBSD: mlkem1024.c,v 1.7 2025/05/03 08:39:33 tb Exp $ */
 /*
  * Copyright (c) 2024, Google Inc.
  * Copyright (c) 2024, Bob Beck <beck@obtuse.com>
@@ -793,6 +793,8 @@ struct public_key {
         matrix m;
 };
 
+CTASSERT(sizeof(struct MLKEM1024_public_key) == sizeof(struct public_key));
+
 static struct public_key *
 public_key_1024_from_external(const struct MLKEM1024_public_key *external)
 {
@@ -805,6 +807,8 @@ struct private_key {
         uint8_t fo_failure_secret[32];
 };
 
+CTASSERT(sizeof(struct MLKEM1024_private_key) == sizeof(struct private_key));
+
 static struct private_key *
 private_key_1024_from_external(const struct MLKEM1024_private_key *external)
 {
diff --git a/src/lib/libcrypto/mlkem/mlkem768.c b/src/lib/libcrypto/mlkem/mlkem768.c
index bacde0c0b7..73e293d542 100644
--- a/src/lib/libcrypto/mlkem/mlkem768.c
+++ b/src/lib/libcrypto/mlkem/mlkem768.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mlkem768.c,v 1.7 2025/01/03 08:19:24 tb Exp $ */
+/* $OpenBSD: mlkem768.c,v 1.8 2025/05/03 08:39:33 tb Exp $ */
 /*
  * Copyright (c) 2024, Google Inc.
  * Copyright (c) 2024, Bob Beck <beck@obtuse.com>
@@ -792,6 +792,8 @@ struct public_key {
         matrix m;
 };
 
+CTASSERT(sizeof(struct MLKEM768_public_key) == sizeof(struct public_key));
+
 static struct public_key *
 public_key_768_from_external(const struct MLKEM768_public_key *external)
 {
@@ -804,6 +806,8 @@ struct private_key {
         uint8_t fo_failure_secret[32];
 };
 
+CTASSERT(sizeof(struct MLKEM768_private_key) == sizeof(struct private_key));
+
 static struct private_key *
 private_key_768_from_external(const struct MLKEM768_private_key *external)
 {