bcrypt: Destroy BCrypt hash context using BCryptDestroyHash(). We allocate

memory for BCrypt hash context from APR pool, so existing code didn't have
memory leak. But in theory BCrypt may have other resources besides memory
used by context itself.

* subversion/libsvn_subr/checksum_bcrypt.c
  (bcrypt_ctx_cleanup): New. APR pool cleanup handler to cleanup bcrypt_ctx_t.
  (bcrypt_ctx_init): Register APR pool cleanup handler.
  (bcrypt_ctx_reset, bcrypt_checksum): Destroy BCrypt hash context using
   BCryptDestroyHash().


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1936009 13f79535-47bb-0310-9956-ffa450edef68

Author: Ivan Zhakov

subversion/libsvn_subr/checksum_bcrypt.c

@@ -93,6 +93,25 @@ typedef struct bcrypt_ctx_t
   apr_pool_t *pool;
 } bcrypt_ctx_t;
 
+/* A cleanup handler. */
+static apr_status_t
+bcrypt_ctx_cleanup(void *data)
+{
+  bcrypt_ctx_t *ctx = data;
+
+  if (ctx->handle)
+    {
+      NTSTATUS status = BCryptDestroyHash(ctx->handle);
+
+      if (!BCRYPT_SUCCESS(status))
+        SVN_ERR_MALFUNCTION_NO_RETURN();
+
+      ctx->handle = NULL;
+    }
+
+  return APR_SUCCESS;
+}
+
 static svn_error_t *
 bcrypt_ctx_init(algorithm_state_t *algorithm,
                 bcrypt_ctx_t *ctx)
@@ -102,8 +121,12 @@ bcrypt_ctx_init(algorithm_state_t *algorithm,
   SVN_ERR(svn_atomic__init_once(&algorithm->initialized, algorithm_init,
                                 algorithm, NULL));
 
-  if (! ctx->object_buf)
-    ctx->object_buf = apr_pcalloc(ctx->pool, algorithm->object_length);
+  if (!ctx->object_buf)
+    {
+      ctx->object_buf = apr_pcalloc(ctx->pool, algorithm->object_length);
+      apr_pool_cleanup_register(ctx->pool, ctx, bcrypt_ctx_cleanup,
+                                apr_pool_cleanup_null);
+    }
 
   SVN_ERR(handle_error(BCryptCreateHash(algorithm->alg_handle,
                                         &handle,
@@ -162,8 +185,14 @@ bcrypt_ctx_final(algorithm_state_t *algorithm,
 static svn_error_t *
 bcrypt_ctx_reset(algorithm_state_t *algorithm, bcrypt_ctx_t *ctx)
 {
+  if (ctx->handle)
+    {
+      SVN_ERR(handle_error(BCryptDestroyHash(ctx->handle)));
+      ctx->handle = NULL;
+    }
+
   memset(ctx->object_buf, 0, algorithm->object_length);
-  ctx->handle = NULL;
+
   return SVN_NO_ERROR;
 }
 
@@ -175,6 +204,7 @@ bcrypt_checksum(algorithm_state_t *algorithm,
 {
   BCRYPT_HANDLE handle;
   void *object_buf;
+  svn_error_t *err;
 
   SVN_ERR(svn_atomic__init_once(&algorithm->initialized, algorithm_init,
                                 algorithm, NULL));
@@ -198,16 +228,29 @@ bcrypt_checksum(algorithm_state_t *algorithm,
       else
         block = UINT_MAX;
 
-      SVN_ERR(handle_error(BCryptHashData(handle, (PUCHAR)data, block,
-                                          /* dwFlags */ 0)));
+      err = handle_error(BCryptHashData(handle, (PUCHAR)data, block,
+                                        /* dwFlags */ 0));
+      if (err)
+        {
+          return svn_error_compose_create(
+            err, handle_error(BCryptDestroyHash(handle)));
+        }
 
       len -= block;
       data += block;
     }
 
-  SVN_ERR(handle_error(BCryptFinishHash(handle, digest,
-                                        algorithm->hash_length,
-                                        /* dwFlags */ 0)));
+  err = handle_error(BCryptFinishHash(handle, digest,
+                                      algorithm->hash_length,
+                                      /* dwFlags */ 0));
+
+  if (err)
+    {
+      return svn_error_compose_create(err,
+                                      handle_error(BCryptDestroyHash(handle)));
+    }
+
+  SVN_ERR(handle_error(BCryptDestroyHash(handle)));
 
   return SVN_NO_ERROR;
 }