From 722390333c4f110c1863aa53931a71824a1dffdd Mon Sep 17 00:00:00 2001
From: Paul Adelsbach <paul.adelsbach@wolfssl.com>
Date: Fri, 18 Sep 2026 15:52:08 -0700
Subject: [PATCH] SHA-3: zeroize working buffers

---
 src/wh_client_crypto.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/wh_client_crypto.c b/src/wh_client_crypto.c
index 893b1c10b..c70654786 100644
--- a/src/wh_client_crypto.c
+++ b/src/wh_client_crypto.c
@@ -9243,6 +9243,7 @@ static int _Sha3UpdateRequest(whClientContext* ctx, wc_Sha3* sha,
 
     /* Pure buffer-fill update: nothing to send. */
     if (wirePos == 0) {
+        wc_ForceZero(savedT, sizeof(savedT));
         return WH_ERROR_OK;
     }
 
@@ -9262,6 +9263,7 @@ static int _Sha3UpdateRequest(whClientContext* ctx, wc_Sha3* sha,
         sha->i = savedI;
         memcpy(sha->t, savedT, savedI);
     }
+    wc_ForceZero(savedT, sizeof(savedT));
     return ret;
 }
 
@@ -9469,6 +9471,8 @@ static int _Sha3Oneshot(whClientContext* ctx, wc_Sha3* sha,
         _Sha3RestoreState(sha, &saved);
     }
 
+    /* The snapshot holds sponge state and message bytes. */
+    wc_ForceZero(&saved, sizeof(saved));
     return ret;
 }
 
@@ -9674,6 +9678,7 @@ static int _Sha3DmaUpdateRequest(whClientContext* ctx, wc_Sha3* sha,
     }
 
     if (wirePos == 0 && dmaSz == 0) {
+        wc_ForceZero(savedT, sizeof(savedT));
         return WH_ERROR_OK;
     }
 
@@ -9718,6 +9723,7 @@ static int _Sha3DmaUpdateRequest(whClientContext* ctx, wc_Sha3* sha,
         }
         memset(&ctx->dma.asyncCtx.sha, 0, sizeof(ctx->dma.asyncCtx.sha));
     }
+    wc_ForceZero(savedT, sizeof(savedT));
     return ret;
 }
 
@@ -9897,6 +9903,8 @@ static int _Sha3DmaOneshot(whClientContext* ctx, wc_Sha3* sha,
         _Sha3RestoreState(sha, &saved);
     }
 
+    /* The snapshot holds sponge state and message bytes. */
+    wc_ForceZero(&saved, sizeof(saved));
     return ret;
 }