From ac11279c60acee6df8e1d18bcc48d1194fb5c526 Mon Sep 17 00:00:00 2001
From: Daniel Pouzzner <douzzer@wolfssl.com>
Date: Mon, 27 Apr 2026 11:37:15 -0500
Subject: [PATCH] wolfcrypt/src/random.c: * add workaround in Hash512_df() for
 gcc compiler bug around AVX512 and object alignment. * add missing
 WC_VERBOSE_RNG clause.

---
 wolfcrypt/src/random.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/wolfcrypt/src/random.c b/wolfcrypt/src/random.c
index 33ff460006..efc9eaf59a 100644
--- a/wolfcrypt/src/random.c
+++ b/wolfcrypt/src/random.c
@@ -1058,8 +1058,16 @@ static int Hash512_df(DRBG_SHA512_internal* drbg, byte* out, word32 outSz,
     byte* digest = drbg->digest_scratch;
 #elif defined(WOLFSSL_SMALL_STACK)
     byte* digest;
+#else
+#if defined(__GNUC__) && !defined(__clang__) && defined(__AVX512F__)
+    /* Use a jumbo alignment to work around a gcc compiler/optimizer bug that
+     * assumes AVX512 alignment in an object sized correctly for AVX512 passed
+     * to builtin memcpy(), which promptly crashes if not thus aligned.
+     */
+    byte digest[WC_SHA512_DIGEST_SIZE] WOLFSSL_ALIGN(WC_SHA512_DIGEST_SIZE);
 #else
     byte digest[WC_SHA512_DIGEST_SIZE];
+#endif
 #endif
 
     if (drbg == NULL) {
@@ -1135,6 +1143,12 @@ static int Hash512_df(DRBG_SHA512_internal* drbg, byte* out, word32 outSz,
     XFREE(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
 #endif
 
+#ifdef WC_VERBOSE_RNG
+    if (ret != 0)
+        WOLFSSL_DEBUG_PRINTF("ERROR: %s failed with err = %d", __FUNCTION__,
+                             ret);
+#endif
+
     return (ret == 0) ? DRBG_SUCCESS : DRBG_FAILURE;
 }