[WIP] [libOS] Single Process lifetime rollback protection for Protected Files

common/src/crypto/adapters/mbedtls_adapter.c

@@ -35,6 +35,7 @@ static int mbedtls_to_pal_error(int error) {
 
         case MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH:
         case MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED:
+        case MBEDTLS_ERR_GCM_BUFFER_TOO_SMALL:
             return PAL_ERROR_CRYPTO_INVALID_INPUT_LENGTH;
 
         case MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE:
@@ -52,6 +53,8 @@ static int mbedtls_to_pal_error(int error) {
         case MBEDTLS_ERR_RSA_PUBLIC_FAILED:  // see mbedtls_rsa_public()
         case MBEDTLS_ERR_RSA_PRIVATE_FAILED: // see mbedtls_rsa_private()
         case MBEDTLS_ERR_ECP_BAD_INPUT_DATA:
+        case MBEDTLS_ERR_GCM_BAD_INPUT:
+        case MBEDTLS_ERR_SHA256_BAD_INPUT_DATA:
             return PAL_ERROR_CRYPTO_BAD_INPUT_DATA;
 
         case MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE:
@@ -71,6 +74,7 @@ static int mbedtls_to_pal_error(int error) {
             return PAL_ERROR_CRYPTO_INVALID_PADDING;
 
         case MBEDTLS_ERR_CIPHER_AUTH_FAILED:
+        case MBEDTLS_ERR_GCM_AUTH_FAILED:
             return PAL_ERROR_CRYPTO_AUTH_FAILED;
 
         case MBEDTLS_ERR_CIPHER_INVALID_CONTEXT:

common/src/protected_files/protected_files.c

@@ -643,8 +643,10 @@ static file_node_t* ipf_read_data_node(pf_context_t* pf, uint64_t offset) {
     if (PF_FAILURE(status)) {
         free(file_data_node);
         pf->last_error = status;
-        if (status == PF_STATUS_MAC_MISMATCH)
+        if (status == PF_STATUS_MAC_MISMATCH) {
             pf->file_status = PF_STATUS_CORRUPTED;
+            pf->last_error  = PF_STATUS_CORRUPTED;
+        }
         return NULL;
     }
 
@@ -706,8 +708,10 @@ static file_node_t* ipf_read_mht_node(pf_context_t* pf, uint64_t logical_mht_nod
     if (PF_FAILURE(status)) {
         free(file_mht_node);
         pf->last_error = status;
-        if (status == PF_STATUS_MAC_MISMATCH)
+        if (status == PF_STATUS_MAC_MISMATCH) {
             pf->file_status = PF_STATUS_CORRUPTED;
+            pf->last_error  = PF_STATUS_CORRUPTED;
+        }
         return NULL;
     }
 
@@ -791,6 +795,11 @@ static bool ipf_init_existing_file(pf_context_t* pf, const char* path) {
     if (PF_FAILURE(status)) {
         pf->last_error = status;
         DEBUG_PF("failed to decrypt metadata: %d", status);
+        if (status == PF_STATUS_MAC_MISMATCH) {
+            // MAC could also mismatch if wrong key was provided but we err on side of safety ...
+            pf->file_status = PF_STATUS_CORRUPTED;
+            pf->last_error  = PF_STATUS_CORRUPTED;
+        }
         return false;
     }
 
@@ -818,6 +827,10 @@ static bool ipf_init_existing_file(pf_context_t* pf, const char* path) {
                                       &pf->metadata_decrypted.root_mht_node_mac);
         if (PF_FAILURE(status)) {
             pf->last_error = status;
+            if (status == PF_STATUS_MAC_MISMATCH) {
+                pf->file_status = PF_STATUS_CORRUPTED;
+                pf->last_error  = PF_STATUS_CORRUPTED;
+            }
             return false;
         }
     }
@@ -1076,7 +1089,7 @@ static void ipf_delete_cache(pf_context_t* pf) {
     }
 }
 
-static bool ipf_close(pf_context_t* pf) {
+static bool ipf_close(pf_context_t* pf, pf_mac_t* closing_root_mac) {
     bool retval = true;
 
     if (pf->file_status != PF_STATUS_SUCCESS) {
@@ -1089,6 +1102,10 @@ static bool ipf_close(pf_context_t* pf) {
         }
     }
 
+    if (closing_root_mac != NULL) {
+        memcpy(*closing_root_mac, pf->metadata_node.plaintext_part.metadata_mac, sizeof(pf_mac_t));
+    }
+
     // omeg: fs close is done by Gramine handler
     pf->file_status = PF_STATUS_UNINITIALIZED;
 
@@ -1126,20 +1143,25 @@ void pf_set_callbacks(pf_read_f read_f, pf_write_f write_f, pf_fsync_f fsync_f,
 }
 
 pf_status_t pf_open(pf_handle_t handle, const char* path, uint64_t underlying_size,
-                    pf_file_mode_t mode, bool create, const pf_key_t* key, pf_context_t** context) {
+                    pf_file_mode_t mode, bool create, const pf_key_t* key,
+                    pf_mac_t* opening_root_mac, pf_context_t** context) {
     if (!g_initialized)
         return PF_STATUS_UNINITIALIZED;
 
     pf_status_t status;
     *context = ipf_open(path, mode, create, handle, underlying_size, key, &status);
+    if ((*context != NULL) && (opening_root_mac != NULL)) {
+        memcpy(*opening_root_mac, (*context)->metadata_node.plaintext_part.metadata_mac,
+               sizeof(pf_mac_t));
+    }
     return status;
 }
 
-pf_status_t pf_close(pf_context_t* pf) {
+pf_status_t pf_close(pf_context_t* pf, pf_mac_t* closing_root_mac) {
     if (!g_initialized)
         return PF_STATUS_UNINITIALIZED;
 
-    if (ipf_close(pf)) {
+    if (ipf_close(pf, closing_root_mac)) {
         free(pf);
         return PF_STATUS_SUCCESS;
     }
@@ -1153,6 +1175,9 @@ pf_status_t pf_get_size(pf_context_t* pf, uint64_t* size) {
     if (!g_initialized)
         return PF_STATUS_UNINITIALIZED;
 
+    if (pf->file_status == PF_STATUS_CORRUPTED)
+        return pf->file_status;  // Make corruption "sticky"
+
     *size = pf->metadata_decrypted.file_size;
     return PF_STATUS_SUCCESS;
 }
@@ -1164,6 +1189,9 @@ pf_status_t pf_set_size(pf_context_t* pf, uint64_t size) {
     if (!(pf->mode & PF_FILE_MODE_WRITE))
         return PF_STATUS_INVALID_MODE;
 
+    if (pf->file_status == PF_STATUS_CORRUPTED)
+        return pf->file_status;  // Make corruption "sticky"
+
     if (size == pf->metadata_decrypted.file_size)
         return PF_STATUS_SUCCESS;
 
@@ -1208,10 +1236,13 @@ pf_status_t pf_set_size(pf_context_t* pf, uint64_t size) {
     return PF_STATUS_SUCCESS;
 }
 
-pf_status_t pf_rename(pf_context_t* pf, const char* new_path) {
+pf_status_t pf_rename(pf_context_t* pf, const char* new_path, pf_mac_t* new_root_mac) {
     if (!g_initialized)
         return PF_STATUS_UNINITIALIZED;
 
+    if (pf->file_status == PF_STATUS_CORRUPTED)
+        return pf->file_status;  // Make corruption "sticky"
+
     if (!(pf->mode & PF_FILE_MODE_WRITE))
         return PF_STATUS_INVALID_MODE;
 
@@ -1224,6 +1255,9 @@ pf_status_t pf_rename(pf_context_t* pf, const char* new_path) {
     pf->need_writing = true;
     if (!ipf_internal_flush(pf))
         return pf->last_error;
+    if (new_root_mac != NULL) {
+        memcpy(*new_root_mac, pf->metadata_node.plaintext_part.metadata_mac, sizeof(pf_mac_t));
+    }
 
     return PF_STATUS_SUCCESS;
 }
@@ -1281,6 +1315,9 @@ pf_status_t pf_flush(pf_context_t* pf) {
     if (!g_initialized)
         return PF_STATUS_UNINITIALIZED;
 
+    if (pf->file_status == PF_STATUS_CORRUPTED)
+        return pf->file_status;  // Make corruption "sticky"
+
     if (!ipf_internal_flush(pf))
         return pf->last_error;
 
@@ -1297,3 +1334,7 @@ pf_status_t pf_flush(pf_context_t* pf) {
 
     return PF_STATUS_SUCCESS;
 }
+
+void pf_set_corrupted(pf_context_t* pf) {
+    pf->file_status = PF_STATUS_CORRUPTED;
+}

common/src/protected_files/protected_files.h

@@ -31,6 +31,11 @@ typedef uint8_t pf_mac_t[PF_MAC_SIZE];
 typedef uint8_t pf_key_t[PF_KEY_SIZE];
 typedef uint8_t pf_nonce_t[PF_NONCE_SIZE];
 
+// convenience macros to print out some mac fingerprint: printf( "some text " MAC_PRINTF_PATTERN "
+// yet other text", MAC_PRINTF_ARGS(mac) );
+#define MAC_PRINTF_PATTERN   "0x%02x%02x%02x%02x..."
+#define MAC_PRINTF_ARGS(mac) (mac)[0], (mac)[1], (mac)[2], (mac)[3]
+
 typedef enum _pf_status_t {
     PF_STATUS_SUCCESS              = 0,
     PF_STATUS_UNKNOWN_ERROR        = -1,
@@ -212,28 +217,31 @@ const char* pf_strerror(int err);
 /*!
  * \brief Open a protected file.
  *
- * \param      handle           Open underlying file handle.
- * \param      path             Path to the file. If NULL and \p create is false, don't check path
- *                              for validity.
- * \param      underlying_size  Underlying file size.
- * \param      mode             Access mode.
- * \param      create           Overwrite file contents if true.
- * \param      key              Wrap key.
- * \param[out] context          PF context for later calls.
+ * \param      handle             Open underlying file handle.
+ * \param      path               Path to the file. If NULL and \p create is false, don't check path
+ *                                for validity.
+ * \param      underlying_size    Underlying file size.
+ * \param      mode               Access mode.
+ * \param      create             Overwrite file contents if true.
+ * \param      key                Wrap key.
+ * \param      opening_root_mac   If non-NULL, !create & successfull open, returns root-hash of file
+ * \param[out] context            PF context for later calls.
  *
  * \returns PF status.
  */
 pf_status_t pf_open(pf_handle_t handle, const char* path, uint64_t underlying_size,
-                    pf_file_mode_t mode, bool create, const pf_key_t* key, pf_context_t** context);
+                    pf_file_mode_t mode, bool create, const pf_key_t* key,
+                    pf_mac_t* opening_root_mac, pf_context_t** context);
 
 /*!
  * \brief Close a protected file and commit all changes to disk.
  *
- * \param pf  PF context.
+ * \param pf                 PF context.
+ * \param closing_root_mac   If non-NULL, returns root-hash of file at closing time
  *
  * \returns PF status.
  */
-pf_status_t pf_close(pf_context_t* pf);
+pf_status_t pf_close(pf_context_t* pf, pf_mac_t* closing_root_mac);
 
 /*!
  * \brief Read from a protected file.
@@ -286,13 +294,14 @@ pf_status_t pf_set_size(pf_context_t* pf, uint64_t size);
 /*!
  * \brief Rename a PF.
  *
- * \param pf        PF context.
- * \param new_path  New file path.
+ * \param pf             PF context.
+ * \param new_path       New file path.
+ * \param new_root_mac   if non-NULL, returns new root-hash of file
  *
  * Updates the path inside protected file header, and flushes all changes. The caller is responsible
  * for renaming the underlying file.
  */
-pf_status_t pf_rename(pf_context_t* pf, const char* new_path);
+pf_status_t pf_rename(pf_context_t* pf, const char* new_path, pf_mac_t* new_root_mac);
 
 /*!
  * \brief Flush any pending data of a protected file to disk.
@@ -302,3 +311,10 @@ pf_status_t pf_rename(pf_context_t* pf, const char* new_path);
  * \returns PF status.
  */
 pf_status_t pf_flush(pf_context_t* pf);
+
+/*!
+ * \brief Set protected file state as corrupted
+ *
+ * \param pf  PF context.
+ */
+void pf_set_corrupted(pf_context_t* pf);

libos/include/libos_fs.h

@@ -35,6 +35,9 @@ struct libos_mount_params {
 
     /* Key name (used by `chroot_encrypted` filesystem), or NULL if not applicable */
     const char* key_name;
+
+    /* Enforcement type (used by `chroot_encrypted` filesystem), or NULL if not applicable */
+    const char* protection_mode;
 };
 
 struct libos_fs_ops {