Implement Key Wrap Demo

examples/demo/client/wh_demo_client_all.c

@@ -47,7 +47,7 @@ int wh_DemoClient_All(whClientContext* clientContext)
 #endif
 
 #ifdef WOLFHSM_CFG_KEYWRAP
-    rc = wh_DemoClient_KeyWrapBasic(clientContext);
+    rc = wh_DemoClient_KeyWrap(clientContext);
     if (rc != 0) {
         return rc;
     }

examples/demo/client/wh_demo_client_keywrap.c

@@ -35,6 +35,29 @@
 
 #ifdef WOLFHSM_CFG_KEYWRAP
 
+#define WH_TEST_KEKID 1
+static int _InitServerKek(whClientContext* ctx)
+{
+    /* IMPORTANT NOTE: Server KEK is typically intrinsic or set during
+     * provisioning. Uploading the KEK via the client is for testing purposes
+     * only and not intended as a recommendation */
+    whKeyId    serverKeyId             = WH_TEST_KEKID;
+    whNvmFlags flags                   = WH_NVM_FLAGS_NONEXPORTABLE;
+    uint8_t    label[WH_NVM_LABEL_LEN] = "Server KEK key";
+    uint8_t    kek[] = {0x03, 0x03, 0x0d, 0xd9, 0xeb, 0x18, 0x17, 0x2e,
+                        0x06, 0x6e, 0x19, 0xce, 0x98, 0x44, 0x54, 0x0d,
+                        0x78, 0xa0, 0xbe, 0xe7, 0x35, 0x43, 0x40, 0xa4,
+                        0x22, 0x8a, 0xd1, 0x0e, 0xa3, 0x63, 0x1c, 0x0b};
+
+    return wh_Client_KeyCache(ctx, flags, label, sizeof(label), kek,
+                              sizeof(kek), &serverKeyId);
+}
+
+static int _CleanupServerKek(whClientContext* ctx)
+{
+    return wh_Client_KeyErase(ctx, WH_TEST_KEKID);
+}
+
 #ifndef NO_AES
 #ifdef HAVE_AESGCM
 
@@ -45,120 +68,202 @@
 #define WH_TEST_AES_WRAPPED_KEYSIZE                                   \
     (WH_TEST_AES_IVSIZE + WH_TEST_AES_TAGSIZE + WH_TEST_AES_KEYSIZE + \
      sizeof(whNvmMetadata))
-#define WH_TEST_WRAPKEY_ID 8
+#define WH_TEST_AESGCM_WRAPKEY_ID 8
 
-int wh_DemoClient_AesGcmKeyWrapBasic(whClientContext* ctx, WC_RNG* rng)
+int wh_DemoClient_AesGcmKeyWrap(whClientContext* client)
 {
     int           ret = 0;
-    uint8_t       kek[WH_TEST_AES_KEYSIZE];
-    uint8_t       clientKey[WH_TEST_AES_KEYSIZE];
-    uint8_t       tmpClientKey[WH_TEST_AES_KEYSIZE];
+    Aes           aes[1];
+    WC_RNG        rng[1];
+    uint8_t       key[WH_TEST_AES_KEYSIZE];
+    uint8_t       exportedKey[WH_TEST_AES_KEYSIZE];
+    whNvmMetadata metadata = {
+        .id    = WH_MAKE_KEYID(WH_KEYTYPE_CRYPTO, 0, WH_TEST_AESGCM_WRAPKEY_ID),
+        .label = "AES Key Label",
+        .access = WH_NVM_ACCESS_ANY,
+        .len    = WH_TEST_AES_KEYSIZE};
+    whNvmMetadata exportedMetadata;
     uint8_t       wrappedKey[WH_TEST_AES_WRAPPED_KEYSIZE];
-    uint8_t       label[WH_NVM_LABEL_LEN] = "Server AES Key Label";
-    whKeyId       serverKeyId;
     whKeyId       wrappedKeyId;
-    whNvmMetadata metadata = {.id     = WH_TEST_WRAPKEY_ID,
-                              .label  = "AES Key Label",
-                              .access = WH_NVM_ACCESS_ANY,
-                              .len    = WH_TEST_AES_KEYSIZE};
-    whNvmMetadata tmpMetadata;
-
-    /* Generate a random KEK to encrypt the client key */
-    ret = wc_RNG_GenerateBlock(rng, kek, sizeof(kek));
-    if (ret != 0) {
-        printf("Failed to wc_RNG_GenerateBlock for key %d\n", ret);
+
+    const uint8_t plaintext[] = "hello, wolfSSL AES-GCM!";
+    uint8_t       ciphertext[sizeof(plaintext)];
+    uint8_t       decrypted[sizeof(plaintext)];
+
+    uint8_t       tag[WH_TEST_AES_TAGSIZE];
+    uint8_t       iv[WH_TEST_AES_IVSIZE];
+    const uint8_t aad[] = {0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe,
+                           0xef, 0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad,
+                           0xbe, 0xef, 0xab, 0xad, 0xda, 0xd2};
+
+    /* Initialize the server KEK */
+
+    /* The key wrap feature requires the server to have a Key Encryption Key
+     * (I.E. KEK) available for the client to use. In the case of this demo we
+     * have the client initializing the KEK which is not recommended. Typically
+     * the KEK ID would be a hard coded value that the client and server share
+     * and the KEK would be provisioned on the server prior to runtime */
+    ret = _InitServerKek(client);
+    if (ret != WH_ERROR_OK) {
+        printf("Failed to _InitServerKek %d\n", ret);
         return ret;
     }
 
-    /* Generate a random client key */
-    ret = wc_RNG_GenerateBlock(rng, clientKey, sizeof(clientKey));
+    /* Generating and wrapping a key */
+
+    /* Initialize the RNG so we can generate an AES GCM key to wrap */
+    ret = wc_InitRng_ex(rng, NULL, WH_DEV_ID);
     if (ret != 0) {
-        printf("Failed to wc_RNG_GenerateBlock for key data %d\n", ret);
-        return ret;
+        printf("Failed to wc_InitRng_ex %d\n", ret);
+        goto cleanup_kek;
     }
 
-    /* Request the server to cache the KEK and give us back a key ID*/
-    ret = wh_Client_KeyCache(ctx, 0, label, sizeof(label), kek, sizeof(kek),
-                             &serverKeyId);
+    /* Now we generate the AES GCM key using the RNG */
+    ret = wc_RNG_GenerateBlock(rng, key, sizeof(key));
     if (ret != 0) {
-        printf("Failed to wh_Client_KeyCache %d\n", ret);
-        return ret;
+        printf("Failed to wc_RNG_GenerateBlock for key data %d\n", ret);
+        goto cleanup_rng;
     }
 
-    /* Request the server to wrap the client key using the KEK we just cached */
-    ret = wh_Client_KeyWrap(ctx, WC_CIPHER_AES_GCM, serverKeyId, clientKey,
-                            sizeof(clientKey), &metadata, wrappedKey,
+    /* Now we request the server to wrap the key using the KEK we
+     * establish above in the first step. */
+    ret = wh_Client_KeyWrap(client, WC_CIPHER_AES_GCM, WH_TEST_KEKID, key,
+                            sizeof(key), &metadata, wrappedKey,
                             sizeof(wrappedKey));
     if (ret != 0) {
         printf("Failed to wh_Client_KeyWrap %d\n", ret);
-        return ret;
+        goto cleanup_rng;
     }
 
-    /* Request the server to unwrap and cache the wrapped key we just created */
-    ret = wh_Client_KeyUnwrapAndCache(ctx, WC_CIPHER_AES_GCM, serverKeyId,
+    /* Now that the key is wrapped you store this in Non-Volatile Memory however
+     * you wish */
+
+
+    /* Using a wrapped key to do crypto operations*/
+
+    /* Request the server to unwrap and cache the wrapped key we just created.
+     * This will provide us back a key ID that the client can use to do crypto
+     * operations */
+    ret = wh_Client_KeyUnwrapAndCache(client, WC_CIPHER_AES_GCM, WH_TEST_KEKID,
                                       wrappedKey, sizeof(wrappedKey),
                                       &wrappedKeyId);
     if (ret != 0) {
         printf("Failed to wh_Client_KeyUnwrapAndCache %d\n", ret);
-        return ret;
+        goto cleanup_rng;
+    }
+
+    /* Initialize AES context */
+    ret = wc_AesInit(aes, NULL, WH_DEV_ID);
+    if (ret != 0) {
+        printf("Failed to wc_AesInit %d\n", ret);
+        goto cleanup_cached_key;
+    }
+
+    /* Set the key id for this AES context to the wrapped key ID that the server
+     * provided us */
+    ret = wh_Client_AesSetKeyId(aes, wrappedKeyId);
+    if (ret != 0) {
+        printf("Failed to wh_Client_AesSetKeyId %d\n", ret);
+        goto cleanup_aes;
+    }
+
+    /* Generate a random IV for the AES GCM encryption operation we are about to
+     * do */
+    ret = wc_RNG_GenerateBlock(rng, iv, sizeof(iv));
+    if (ret != 0) {
+        printf("Failed to wc_RNG_GenerateBlock for AES-GCM key %d\n", ret);
+        goto cleanup_aes;
     }
 
+    /* Request the server to encrypt some data using the
+     * unwrapped and cached key via the key ID */
+    ret = wc_AesGcmEncrypt(aes, ciphertext, plaintext, sizeof(plaintext), iv,
+                           sizeof(iv), tag, sizeof(tag), aad, sizeof(aad));
+    if (ret != 0) {
+        printf("Failed to wc_AesGcmEncrypt %d\n", ret);
+        goto cleanup_aes;
+    }
+
+    /* Request the server to decrypt the encrypted data using the
+     * unwrapped and cached key via the key ID */
+    ret = wc_AesGcmDecrypt(aes, decrypted,                 /* out */
+                           ciphertext, sizeof(ciphertext), /* in, inLen */
+                           iv, sizeof(iv),                 /* iv, ivLen */
+                           tag, sizeof(tag),  /* authTag, authTagSz */
+                           aad, sizeof(aad)); /* authIn (AAD), authInSz */
+    if (ret != 0) {
+        ret = WH_ERROR_ABORTED;
+        printf("Failed to wc_AesGcmDecrypt %d\n", ret);
+        goto cleanup_aes;
+    }
+
+    /* Check if the decrypted data matches an expected value */
+    if (memcmp(decrypted, plaintext, sizeof(decrypted)) != 0) {
+        ret = WH_ERROR_ABORTED;
+        printf("Decrypted value does not match expected value\n");
+        goto cleanup_aes;
+    }
+
+    /* Exporting a wrapped key */
+
     /* Request the server to unwrap and export the wrapped key we created */
-    ret = wh_Client_KeyUnwrapAndExport(
-        ctx, WC_CIPHER_AES_GCM, serverKeyId, wrappedKey, sizeof(wrappedKey),
-        &tmpMetadata, tmpClientKey, sizeof(tmpClientKey));
+    ret = wh_Client_KeyUnwrapAndExport(client, WC_CIPHER_AES_GCM, WH_TEST_KEKID,
+                                       wrappedKey, sizeof(wrappedKey),
+                                       &exportedMetadata, exportedKey,
+                                       sizeof(exportedKey));
     if (ret != 0) {
         printf("Failed to wh_Client_KeyUnwrapAndCache %d\n", ret);
-        return ret;
+        goto cleanup_aes;
     }
 
-
     /* Compare the exported key to the client key we requested to wrap */
-    if (memcmp(clientKey, tmpClientKey, sizeof(clientKey)) != 0) {
+    if (memcmp(key, exportedKey, sizeof(key)) != 0) {
+        ret = WH_ERROR_ABORTED;
         printf("AES GCM wrap/unwrap key failed to match\n");
-        return ret;
+        goto cleanup_aes;
     }
 
     /* Compare the exported metadata to the metadata we requested to wrap */
-    if (memcmp(&metadata, &tmpMetadata, sizeof(metadata)) != 0) {
+    if (memcmp(&metadata, &exportedMetadata, sizeof(metadata)) != 0) {
+        ret = WH_ERROR_ABORTED;
         printf("AES GCM wrap/unwrap metadata failed to match\n");
-        return ret;
+        goto cleanup_aes;
     }
 
+cleanup_aes:
+    wc_AesFree(aes);
+cleanup_cached_key:
+    wh_Client_KeyErase(client, wrappedKeyId);
+cleanup_rng:
+    wc_FreeRng(rng);
+cleanup_kek:
+    _CleanupServerKek(client);
+
     return ret;
 }
 
 #endif /* HAVE_AESGCM */
 
-int wh_DemoClient_AesKeyWrapBasic(whClientContext* clientContext, WC_RNG* rng)
-{
-    int ret = WH_ERROR_OK;
-
-#ifdef HAVE_AESGCM
-    ret = wh_DemoClient_AesGcmKeyWrapBasic(clientContext, rng);
-#endif
-
-    return ret;
-}
 
 #endif /* !NO_AES */
-int wh_DemoClient_KeyWrapBasic(whClientContext* clientContext)
+
+int wh_DemoClient_KeyWrap(whClientContext* client)
 {
 
-    int    ret;
-    WC_RNG rng[1];
+    int ret;
 
-    ret = wc_InitRng_ex(rng, NULL, WH_DEV_ID);
-    if (ret != 0) {
-        printf("Failed to wc_InitRng_ex %d\n", ret);
+#ifndef NO_AES
+#ifdef HAVE_AESGCM
+
+    ret = wh_DemoClient_AesGcmKeyWrap(client);
+    if (ret != WH_ERROR_OK) {
+        printf("Failed to wh_DemoClient_AesGcmKeyWrap %d\n", ret);
         return ret;
     }
 
-#ifndef NO_AES
-    ret = wh_DemoClient_AesKeyWrapBasic(clientContext, rng);
-#endif
+#endif /* !NO_AES */
+#endif /* HAVE_AESGCM */
 
-    wc_FreeRng(rng);
     return ret;
 }
 #endif /* WOLFHSM_CFG_KEYWRAP */

examples/demo/client/wh_demo_client_keywrap.h

@@ -3,6 +3,6 @@
 
 #include "wolfhsm/wh_client.h"
 
-int wh_DemoClient_KeyWrapBasic(whClientContext* clientContext);
+int wh_DemoClient_KeyWrap(whClientContext* clientContext);
 
 #endif /* !DEMO_CLIENT_KEYWRAP_H_ */

examples/posix/wh_posix_client/Makefile

@@ -108,6 +108,7 @@ SRC_C +=  $(wildcard $(WOLFHSM_DIR)/src/*.c)
 # wolfHSM port/HAL code
 SRC_C +=  $(wildcard $(WOLFHSM_PORT_DIR)/*.c)
 
+
 # Project
 SRC_C +=  $(wildcard $(PROJECT_DIR)/*.c)
 

examples/posix/wh_posix_client/wolfhsm_cfg.h

@@ -28,7 +28,7 @@
 /** wolfHSM settings */
 #define WOLFHSM_CFG_ENABLE_CLIENT
 #define WOLFHSM_CFG_HEXDUMP
-#define WOLFHSM_CFG_COMM_DATA_LEN 1280
+#define WOLFHSM_CFG_COMM_DATA_LEN 5000
 #define WOLFHSM_CFG_KEYWRAP
 
 #endif /* WOLFHSM_CFG_H_ */

examples/posix/wh_posix_server/wolfhsm_cfg.h

@@ -44,6 +44,8 @@
 #define WOLFHSM_CFG_CERTIFICATE_MANAGER
 #define WOLFHSM_CFG_CERTIFICATE_MANAGER_ACERT
 
+#define WOLFHSM_CFG_KEYWRAP_MAX_KEY_SIZE 5000
+
 #define XMEMFENCE() __atomic_thread_fence(__ATOMIC_SEQ_CST)
 #define WOLFHSM_CFG_KEYWRAP
 

src/wh_client_keywrap.c

@@ -1,6 +1,7 @@
 /* Pick up compile-time configuration */
 #include "wolfhsm/wh_settings.h"
 
+#if defined(WOLFHSM_CFG_KEYWRAP)
 #if defined(WOLFHSM_CFG_ENABLE_CLIENT)
 #include <stdint.h>
 #include <wolfhsm/wh_client.h>
@@ -326,3 +327,4 @@ int wh_Client_KeyUnwrapAndCache(whClientContext*   ctx,
 }
 
 #endif /* WOLFHSM_CFG_ENABLE_CLIENT */
+#endif /* WOLFHSM_CFG_KEYWRAP */

test/config/wolfhsm_cfg.h

@@ -46,6 +46,8 @@
 /* Enable Image Manager feature */
 #define WOLFHSM_CFG_SERVER_IMG_MGR
 
+#ifndef WOLFHSM_CFG_NO_CRYPTO
 #define WOLFHSM_CFG_KEYWRAP
+#endif
 
 #endif /* WOLFHSM_CFG_H_ */