Fix NS350 RSA-4096 Failures

examples/csr/csr.c

@@ -60,7 +60,14 @@ static const char* gClientCertEccFile = ECC_CERT_PEM;
 #endif
 
 #ifndef MAX_PEM_SIZE
-#define MAX_PEM_SIZE MAX_CONTEXT_SIZE
+    /* Must hold the full PEM-encoded CSR/cert (cert body + RSA signature +
+     * ASN.1 + base64 overhead). MAX_CONTEXT_SIZE (2 KB) fits RSA-2048 but
+     * overflows at RSA-4096 where the signature alone is 512 B. */
+    #if MAX_RSA_KEY_BITS >= 4096
+        #define MAX_PEM_SIZE 4096
+    #else
+        #define MAX_PEM_SIZE MAX_CONTEXT_SIZE
+    #endif
 #endif
 
 /******************************************************************************/

examples/keygen/keygen.c

@@ -132,7 +132,7 @@ int TPM2_Keygen_Example(void* userCtx, int argc, char *argv[])
     WOLFTPM2_KEYBLOB primaryBlob; /* Primary key as WOLFTPM2_KEYBLOB */
     TPMT_PUBLIC publicTemplate;
     TPMI_ALG_PUBLIC alg = TPM_ALG_RSA; /* default, see usage() for options */
-    TPMI_ALG_PUBLIC srkAlg = TPM_ALG_ECC; /* prefer ECC, but allow RSA */
+    TPMI_ALG_PUBLIC srkAlg = TPM_ALG_RSA; /* default matches seal.c / keyload.c */
     TPM_ALG_ID algSym = TPM_ALG_CTR; /* default Symmetric Cipher, see usage */
     TPM_ALG_ID paramEncAlg = TPM_ALG_NULL;
     WOLFTPM2_SESSION tpmSession;
@@ -222,8 +222,10 @@ int TPM2_Keygen_Example(void* userCtx, int argc, char *argv[])
     XMEMSET(&tpmSession, 0, sizeof(tpmSession));
     XMEMSET(&auth, 0, sizeof(auth));
 
-    if (alg == TPM_ALG_RSA)
-        srkAlg = TPM_ALG_RSA;
+    /* Only use the ECC SRK for ECC child keys; RSA, SYMCIPHER, KEYEDHASH
+     * all stay on the RSA SRK so that keyload/seal can round-trip them. */
+    if (alg == TPM_ALG_ECC)
+        srkAlg = TPM_ALG_ECC;
     if (alg == TPM_ALG_SYMCIPHER) {
         rc = symChoice(symMode, &algSym, &keyBits);
         if (rc != TPM_RC_SUCCESS) {

examples/keygen/keyload.c

@@ -67,7 +67,7 @@ int TPM2_Keyload_Example(void* userCtx, int argc, char *argv[])
     WOLFTPM2_KEYBLOB newKey;
     WOLFTPM2_KEY persistKey;
     TPM_ALG_ID alg;
-    TPMI_ALG_PUBLIC srkAlg = TPM_ALG_ECC; /* prefer ECC, but allow RSA */
+    TPMI_ALG_PUBLIC srkAlg = TPM_ALG_RSA; /* default matches seal.c */
     TPM_ALG_ID paramEncAlg = TPM_ALG_NULL;
     WOLFTPM2_SESSION tpmSession;
     const char* inputFile = "keyblob.bin";
@@ -133,8 +133,11 @@ int TPM2_Keyload_Example(void* userCtx, int argc, char *argv[])
 #endif
 
     alg = newKey.pub.publicArea.type;
-    if (alg == TPM_ALG_RSA)
-        srkAlg = TPM_ALG_RSA;
+    /* Only switch to the ECC SRK when the stored key itself is ECC; other
+     * child types (RSA, KEYEDHASH from seal, SYMCIPHER) stay on the RSA SRK
+     * so the parent algorithm matches how those keys were created. */
+    if (alg == TPM_ALG_ECC)
+        srkAlg = TPM_ALG_ECC;
     printf("Loading %s key\n", TPM2_GetAlgName(alg));
 
     if (endorseKey) {

examples/nvram/read.c

@@ -267,8 +267,12 @@ int TPM2_NVRAM_Read_Example(void* userCtx, int argc, char *argv[])
         nvIndex);
 
     if (!nvExtend && !partialRead) {
-        /* get SRK */
-        rc = getPrimaryStoragekey(&dev, &storage, TPM_ALG_RSA);
+        /* Select the SRK algorithm based on the stored key's type so an
+         * ECC child isn't loaded under an RSA parent (or vice versa). */
+        TPMI_ALG_PUBLIC srkAlg =
+            (keyBlob.pub.publicArea.type == TPM_ALG_ECC)
+                ? TPM_ALG_ECC : TPM_ALG_RSA;
+        rc = getPrimaryStoragekey(&dev, &storage, srkAlg);
         if (rc != 0) goto exit;
 
         printf("Trying to load the key extracted from NVRAM\n");

examples/pkcs7/pkcs7.c

@@ -57,7 +57,14 @@
 #endif
 
 #ifndef MAX_PKCS7_SIZE
-#define MAX_PKCS7_SIZE MAX_CONTEXT_SIZE
+    /* Must hold the full SignedData blob (cert + signature + ASN.1 overhead).
+     * MAX_CONTEXT_SIZE (2 KB) is enough for RSA-2048 but overflows at
+     * RSA-4096 where the signature alone is 512 B. */
+    #if MAX_RSA_KEY_BITS >= 4096
+        #define MAX_PKCS7_SIZE 4096
+    #else
+        #define MAX_PKCS7_SIZE MAX_CONTEXT_SIZE
+    #endif
 #endif
 
 /******************************************************************************/

examples/wrap/wrap_test.c

@@ -338,7 +338,9 @@ int TPM2_Wrapper_TestArgs(void* userCtx, int argc, char *argv[])
     if (rc != 0) goto exit;
 
     /* Perform RSA encrypt / decrypt (no pad) */
-    message.size = 256; /* test message 0x11,0x11,etc */
+    /* With TPM_ALG_NULL padding, the TPM returns a full modulus-sized
+     * plaintext on decrypt, so the message must also be modulus-sized. */
+    message.size = rsaKey.pub.publicArea.parameters.rsaDetail.keyBits / 8;
     XMEMSET(message.buffer, 0x11, message.size);
     cipher.size = sizeof(cipher.buffer); /* encrypted data */
     rc = wolfTPM2_RsaEncrypt(&dev, &rsaKey, TPM_ALG_NULL,