Fix Copilot x Fenrir review

Author: aidangarske

src/spdm/spdm_context.c

@@ -414,10 +414,11 @@ int wolfSPDM_SendReceive(WOLFSPDM_CTX* ctx,
                 tcgTx, sizeof(tcgTx));
         } else {
             /* Secured record - prepend TCG secured header (0x8201) */
-            word32 totalSz = WOLFSPDM_TCG_HEADER_SIZE + txSz;
-            if (totalSz > sizeof(tcgTx)) {
+            word32 totalSz;
+            if (txSz > sizeof(tcgTx) - WOLFSPDM_TCG_HEADER_SIZE) {
                 return WOLFSPDM_E_BUFFER_SMALL;
             }
+            totalSz = WOLFSPDM_TCG_HEADER_SIZE + txSz;
             wolfSPDM_WriteTcgHeader(tcgTx, WOLFSPDM_TCG_TAG_SECURED,
                 totalSz, ctx->connectionHandle, ctx->fipsIndicator);
             XMEMCPY(tcgTx + WOLFSPDM_TCG_HEADER_SIZE, txBuf, txSz);

src/spdm/spdm_tcg.c

@@ -495,24 +495,6 @@ int wolfSPDM_ConnectTCG(WOLFSPDM_CTX* ctx)
     }
 #endif
 
-    /* SPDM 1.3+: Replace VCA with Hash(VCA) in transcript.
-     * DSP0274 1.3 section 10.17.1: th = Hash(Hash(A) || Ct || K)
-     * TODO: verify with both Nuvoton and Nations hardware */
-    if (0 && ctx->spdmVersion >= SPDM_VERSION_13 && ctx->transcriptLen > 12) {
-        byte vcaHash[WOLFSPDM_HASH_SIZE];
-        rc = wolfSPDM_TranscriptHash(ctx, vcaHash);
-        if (rc == WOLFSPDM_SUCCESS) {
-            wolfSPDM_TranscriptReset(ctx);
-            rc = wolfSPDM_TranscriptAdd(ctx, vcaHash, WOLFSPDM_HASH_SIZE);
-            wolfSPDM_DebugPrint(ctx, "TCG: VCA hashed (%u -> %u bytes)\n",
-                ctx->transcriptLen, WOLFSPDM_HASH_SIZE);
-        }
-        if (rc != WOLFSPDM_SUCCESS) {
-            ctx->state = WOLFSPDM_STATE_ERROR;
-            return rc;
-        }
-    }
-
     /* Step 4: GET_PUBK */
     wolfSPDM_DebugPrint(ctx, "TCG Step 4: GET_PUBK\n");
     pubKeySz = sizeof(pubKey);