From e9e1e36d69b33aa8df63b7acc0d0ffe4f3d38cd9 Mon Sep 17 00:00:00 2001
From: Aidan Garske <aidan@wolfssl.com>
Date: Mon, 27 Jul 2026 13:00:56 -0700
Subject: [PATCH] F-7281 - Scrub SPI transfer buffers in the advanced IO
 callback

---
 hal/tpm_io.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hal/tpm_io.c b/hal/tpm_io.c
index d5757c4d..4590395e 100644
--- a/hal/tpm_io.c
+++ b/hal/tpm_io.c
@@ -208,6 +208,12 @@ int TPM2_IoCb(TPM2_CTX* ctx, INT32 isRead, UINT32 addr,
     }
 #endif
 
+#if !defined(WOLFTPM_I2C) && !defined(WOLFTPM_MMIO) && !defined(WOLFTPM_FWTPM_HAL)
+    /* the FIFO register transfers plaintext command/response payload */
+    TPM2_ForceZero(txBuf, sizeof(txBuf));
+    TPM2_ForceZero(rxBuf, sizeof(rxBuf));
+#endif
+
     (void)ctx;
 
     return ret;