Wrapped key overhaul using flags to ensure server can uniquely ID them

Author: bigbrett

examples/demo/client/wh_demo_client_keywrap.c

@@ -77,10 +77,11 @@ int wh_DemoClient_AesGcmKeyWrap(whClientContext* client)
     WC_RNG        rng[1];
     uint8_t       key[WH_DEMO_KEYWRAP_AES_KEYSIZE];
     uint8_t       exportedKey[WH_DEMO_KEYWRAP_AES_KEYSIZE];
-    whNvmMetadata metadata = {.id     = WH_DEMO_KEYWRAP_AESGCM_WRAPKEY_ID,
-                              .label  = "AES Key Label",
-                              .access = WH_NVM_ACCESS_ANY,
-                              .len    = WH_DEMO_KEYWRAP_AES_KEYSIZE};
+    whNvmMetadata metadata = {
+        .id     = WH_MAKE_KEYID_WRAPPED(WH_DEMO_KEYWRAP_AESGCM_WRAPKEY_ID),
+        .label  = "AES Key Label",
+        .access = WH_NVM_ACCESS_ANY,
+        .len    = WH_DEMO_KEYWRAP_AES_KEYSIZE};
     whNvmMetadata exportedMetadata;
     uint8_t       wrappedKey[WH_DEMO_KEYWRAP_AES_WRAPPED_KEYSIZE];
     whKeyId       wrappedKeyId;

examples/posix/wh_posix_server/wh_posix_server.c

@@ -29,8 +29,6 @@
 
 #include "wh_posix_cfg.h"
 #include "wh_posix_server_cfg.h"
-/* For demo wrapped key ID registration */
-#include "../../demo/client/wh_demo_client_keywrap.h"
 
 /** Local declarations */
 static int wh_ServerTask(void* cf, const char* keyFilePath, int keyId,
@@ -126,20 +124,6 @@ static int _InitDemoServer(whServerContext* server, whServerConfig* config)
 
     ret = wh_Server_Init(server, config);
 
-#ifdef WOLFHSM_CFG_KEYWRAP
-    if (ret == WH_ERROR_OK) {
-        /* Register wrapped keys from demo client (wh_demo_client_keywrap.h) */
-        const whKeyId wrappedIds[] = {WH_DEMO_KEYWRAP_AESGCM_WRAPKEY_ID};
-        ret                        = wh_Server_KeystoreRegisterWrappedKeys(
-                                   server, wrappedIds,
-                                   (uint16_t)(sizeof(wrappedIds) / sizeof(wrappedIds[0])));
-        if (ret != WH_ERROR_OK) {
-            printf("Failed to register wrapped key IDs: %d\n", ret);
-            (void)wh_Server_Cleanup(server);
-        }
-    }
-#endif
-
     return ret;
 }
 

src/wh_client_keywrap.c

@@ -298,7 +298,7 @@ int wh_Client_KeyUnwrapAndCacheResponse(whClientContext*   ctx,
         return resp->rc;
     }
 
-    *keyIdOut = resp->keyId;
+    *keyIdOut = WH_MAKE_KEYID_WRAPPED(resp->keyId);
 
     return WH_ERROR_OK;
 }

src/wh_server_keystore.c

@@ -82,98 +82,6 @@ static whKeyCacheContext* _GetCacheContext(whServerContext* server,
     return &server->localCache;
 }
 
-#ifdef WOLFHSM_CFG_KEYWRAP
-/*
- * @brief Retrieve the wrapped-key registry associated with keyId
- */
-static whWrappedKeyRegistry* _GetWrappedRegistry(whServerContext* server,
-                                                 whKeyId          keyId)
-{
-    whKeyCacheContext* ctx = _GetCacheContext(server, keyId);
-    return (ctx != NULL) ? &ctx->wrappedKeys : NULL;
-}
-
-/**
- * @brief Check if keyId is present in a wrapped-key registry
- *
- * Note: Registry stores client-relative IDs (0-255), so keyId parameter
- * should be the extracted client-relative ID, not a full server-encoded keyId.
- */
-static int _WrappedRegistryContains(const whWrappedKeyRegistry* registry,
-                                    whKeyId                     keyId)
-{
-    uint16_t i;
-
-    if (registry == NULL) {
-        return 0;
-    }
-
-    for (i = 0; i < registry->count; i++) {
-        if (registry->ids[i] == keyId) {
-            return 1;
-        }
-    }
-    return 0;
-}
-
-/**
- * @brief Add keyId to a wrapped-key registry if not already present
- *
- * Extracts and stores only the client-relative ID portion (0-255) from keyId.
- * This allows registration before knowing which client will connect.
- */
-static int _WrappedRegistryAdd(whWrappedKeyRegistry* registry, whKeyId keyId)
-{
-    uint8_t clientRelativeId;
-
-    if (registry == NULL) {
-        return WH_ERROR_BADARGS;
-    }
-
-    /* Extract client-relative ID portion (0-255) from keyId */
-    clientRelativeId = WH_KEYID_ID(keyId);
-
-    if (clientRelativeId == WH_KEYID_ERASED) {
-        return WH_ERROR_BADARGS;
-    }
-
-    /* Check if already registered (using client-relative ID) */
-    if (_WrappedRegistryContains(registry, (whKeyId)clientRelativeId)) {
-        return WH_ERROR_OK;
-    }
-
-    if (registry->count >= WOLFHSM_CFG_SERVER_WRAPPED_KEY_COUNT) {
-        return WH_ERROR_NOSPACE;
-    }
-
-    /* Store only the client-relative ID portion */
-    registry->ids[registry->count++] = (whKeyId)clientRelativeId;
-    return WH_ERROR_OK;
-}
-
-/**
- * @brief Determine if a keyId is registered as a wrapped key
- *
- * Extracts the client-relative ID portion from keyId before checking registry.
- * This allows the registry to match regardless of the client ID encoded in
- * keyId.
- */
-static int _IsKnownWrappedKey(whServerContext* server, whKeyId keyId)
-{
-    whWrappedKeyRegistry* registry;
-    uint8_t               clientRelativeId;
-
-    /* Get the appropriate registry (local or global) based on keyId encoding */
-    registry = _GetWrappedRegistry(server, keyId);
-
-    /* Extract client-relative ID (0-255) for comparison */
-    clientRelativeId = WH_KEYID_ID(keyId);
-
-    /* Registry stores client-relative IDs, so pass extracted ID */
-    return _WrappedRegistryContains(registry, (whKeyId)clientRelativeId);
-}
-#endif /* WOLFHSM_CFG_KEYWRAP */
-
 /**
  * @brief Find a key in the specified cache context
  */
@@ -354,19 +262,17 @@ int wh_Server_KeystoreGetUniqueId(whServerContext* server, whNvmId* inout_id)
 
     whKeyCacheContext* ctx = _GetCacheContext(server, key_id);
 
+    /* Wrapped keys must be provisioned with explicit identifiers */
+    if (type == WH_KEYTYPE_WRAPPED) {
+        return WH_ERROR_BADARGS;
+    }
+
     /* try every index until we find a unique one, don't worry about capacity */
     for (id = WH_KEYID_IDMAX; id > WH_KEYID_ERASED; id--) {
         /* id loop var is not an input client ID so we don't need to handle the
          * global case */
         buildId = WH_MAKE_KEYID(type, user, id);
 
-#ifdef WOLFHSM_CFG_KEYWRAP
-        /* Skip over known wrapped keys */
-        if (_IsKnownWrappedKey(server, buildId)) {
-            continue;
-        }
-#endif
-
         /* Check against cache keys using unified cache functions */
         ret = _FindInKeyCache(ctx, buildId, NULL, NULL, NULL, NULL);
         if (ret == WH_ERROR_OK) {
@@ -579,6 +485,26 @@ static int _ExistsInCache(whServerContext* server, whKeyId keyId)
 }
 #endif /* WOLFHSM_CFG_KEYWRAP */
 
+#ifdef WOLFHSM_CFG_KEYWRAP
+int wh_Server_KeystoreIsWrappedKey(whServerContext* server, whKeyId keyId,
+                                   int* outIsWrapped)
+{
+    int isWrapped;
+
+    if (server == NULL || WH_KEYID_ISERASED(keyId)) {
+        return WH_ERROR_BADARGS;
+    }
+
+    (void)server;
+    isWrapped = (WH_KEYID_TYPE(keyId) == WH_KEYTYPE_WRAPPED);
+    if (outIsWrapped != NULL) {
+        *outIsWrapped = isWrapped;
+    }
+
+    return WH_ERROR_OK;
+}
+#endif /* WOLFHSM_CFG_KEYWRAP */
+
 /* try to put the specified key into cache if it isn't already, return pointers
  * to meta and the cached data*/
 int wh_Server_KeystoreFreshenKey(whServerContext* server, whKeyId keyId,
@@ -593,12 +519,10 @@ int wh_Server_KeystoreFreshenKey(whServerContext* server, whKeyId keyId,
         return WH_ERROR_BADARGS;
     }
 
-#ifdef WOLFHSM_CFG_KEYWRAP
-    /* Reject attempts to freshen a known wrapped key */
-    if (_IsKnownWrappedKey(server, keyId)) {
+    /* Reject attempts to freshen wrapped keys from NVM */
+    if (WH_KEYID_TYPE(keyId) == WH_KEYTYPE_WRAPPED) {
         return WH_ERROR_ABORTED;
     }
-#endif
 
     ret = _FindInCache(server, keyId, &foundIndex, &foundBigIndex, outBuf,
                        outMeta);
@@ -658,12 +582,10 @@ int wh_Server_KeystoreReadKey(whServerContext* server, whKeyId keyId,
         return 0;
     }
 
-#ifdef WOLFHSM_CFG_KEYWRAP
     /* Prevent exposing wrapped blobs through the unwrapped read path */
-    if (_IsKnownWrappedKey(server, keyId)) {
+    if (WH_KEYID_TYPE(keyId) == WH_KEYTYPE_WRAPPED) {
         return WH_ERROR_NOTFOUND;
     }
-#endif
 
     /* Not in cache, try to read the metadata from NVM */
     ret = wh_Nvm_GetMetadata(server->nvm, keyId, meta);
@@ -737,11 +659,9 @@ int wh_Server_KeystoreCommitKey(whServerContext* server, whNvmId keyId)
         return WH_ERROR_BADARGS;
     }
 
-#ifdef WOLFHSM_CFG_KEYWRAP
-    if (_IsKnownWrappedKey(server, keyId)) {
+    if (WH_KEYID_TYPE(keyId) == WH_KEYTYPE_WRAPPED) {
         return WH_ERROR_ABORTED;
     }
-#endif
 
     /* Get the appropriate cache context for this key */
     ctx = _GetCacheContext(server, keyId);
@@ -765,11 +685,9 @@ int wh_Server_KeystoreEraseKey(whServerContext* server, whNvmId keyId)
         return WH_ERROR_BADARGS;
     }
 
-#ifdef WOLFHSM_CFG_KEYWRAP
-    if (_IsKnownWrappedKey(server, keyId)) {
+    if (WH_KEYID_TYPE(keyId) == WH_KEYTYPE_WRAPPED) {
         return WH_ERROR_ABORTED;
     }
-#endif
 
     /* remove the key from the cache if present */
     (void)wh_Server_KeystoreEvictKey(server, keyId);
@@ -778,54 +696,6 @@ int wh_Server_KeystoreEraseKey(whServerContext* server, whNvmId keyId)
     return wh_Nvm_DestroyObjects(server->nvm, 1, &keyId);
 }
 
-#ifdef WOLFHSM_CFG_KEYWRAP
-int wh_Server_KeystoreRegisterWrappedKeys(whServerContext* server,
-                                          const whKeyId* keyIds, size_t count)
-{
-    uint16_t i;
-    int      ret;
-
-    if (server == NULL || keyIds == NULL || count == 0) {
-        return WH_ERROR_BADARGS;
-    }
-
-    if (count > WOLFHSM_CFG_SERVER_WRAPPED_KEY_COUNT) {
-        return WH_ERROR_BADARGS;
-    }
-
-    for (i = 0; i < count; i++) {
-        whWrappedKeyRegistry* registry = _GetWrappedRegistry(server, keyIds[i]);
-        ret = _WrappedRegistryAdd(registry, keyIds[i]);
-        if (ret != WH_ERROR_OK) {
-            return ret;
-        }
-    }
-
-    return WH_ERROR_OK;
-}
-
-int wh_Server_KeystoreRegisterWrappedKey(whServerContext* server, whKeyId keyId)
-{
-    return wh_Server_KeystoreRegisterWrappedKeys(server, &keyId, 1);
-}
-
-int wh_Server_KeystoreIsWrappedKey(whServerContext* server, whKeyId keyId,
-                                   int* outIsWrapped)
-{
-    int isWrapped;
-
-    if (server == NULL || WH_KEYID_ISERASED(keyId)) {
-        return WH_ERROR_BADARGS;
-    }
-
-    isWrapped = _IsKnownWrappedKey(server, keyId);
-    if (outIsWrapped != NULL) {
-        *outIsWrapped = isWrapped;
-    }
-
-    return WH_ERROR_OK;
-}
-
 #ifndef NO_AES
 #ifdef HAVE_AESGCM
 
@@ -1001,6 +871,10 @@ static int _HandleWrapKeyRequest(whServerContext*               server,
     memcpy(&metadata, reqData, sizeof(metadata));
     memcpy(key, reqData + sizeof(metadata), req->keySz);
 
+    if (!WH_KEYID_ISWRAPPED(metadata.id)) {
+        return WH_ERROR_CONFIG;
+    }
+
     /* Store the wrapped key in the response data */
     wrappedKey = respData;
 
@@ -1089,6 +963,10 @@ static int _HandleUnwrapAndExportKeyRequest(
                 return ret;
             }
 
+            if (!WH_KEYID_ISWRAPPED(metadata->id)) {
+                return WH_ERROR_CONFIG;
+            }
+
             /* Check if the key is exportable */
             if (metadata->flags & WH_NVM_FLAGS_NONEXPORTABLE) {
                 return WH_ERROR_ACCESS;
@@ -1177,9 +1055,8 @@ _HandleUnwrapAndCacheKeyRequest(whServerContext*                         server,
     metadata.id = WH_TRANSLATE_CLIENT_KEYID(
         WH_KEYTYPE_CRYPTO, server->comm->client_id, metadata.id);
 
-    /* If not a known wrapped key then there is a configuration error, we can't
-     * handle unknown wrapped keys in the system */
-    if (!_IsKnownWrappedKey(server, metadata.id)) {
+    /* Require explicit wrapped-key encoding */
+    if (WH_KEYID_TYPE(metadata.id) != WH_KEYTYPE_WRAPPED) {
         return WH_ERROR_CONFIG;
     }
 
@@ -1191,14 +1068,12 @@ _HandleUnwrapAndCacheKeyRequest(whServerContext*                         server,
     /* Store the assigned key ID in the response (ID portion only). We should
      * NOT return the upper bits back to the client */
     /* TODO: should we not return the global bit? */
-    resp->keyId = WH_KEYID_ID(metadata.id);
+    resp->keyId = WH_KEYID_TO_CLIENT(metadata.id);
 
     /* Cache the key */
     return wh_Server_KeystoreCacheKey(server, &metadata, key);
 }
 
-#endif /* WOLFHSM_CFG_KEYWRAP */
-
 int wh_Server_HandleKeyRequest(whServerContext* server, uint16_t magic,
                                uint16_t action, uint16_t req_size,
                                const void* req_packet, uint16_t* out_resp_size,