prepare_metadata_resource(): Check for size overflow

diff --git a/src/metadata_resource.c b/src/metadata_resource.c
index ebd3332b9b773a06b7afd92376e1708c33e3feff..206c274ab0fa0a587344b60a530e376e9feeb68f 100644 (file)
--- a/src/metadata_resource.c
+++ b/src/metadata_resource.c
@@ -152,7 +152,7 @@ prepare_metadata_resource(WIMStruct *wim, int image,
        int ret;
        u64 subdir_offset;
        struct wim_dentry *root;
-       u64 len;
+       size_t len;
        struct wim_security_data *sd;
        struct wim_image_metadata *imd;
 
@@ -193,10 +193,12 @@ prepare_metadata_resource(WIMStruct *wim, int image,
        len = subdir_offset;
 
        /* Allocate a buffer to contain the uncompressed metadata resource.  */
-       buf = MALLOC(len);
+       buf = NULL;
+       if (likely(len == subdir_offset))
+               buf = MALLOC(len);
        if (!buf) {
                ERROR("Failed to allocate %"PRIu64" bytes for "
-                     "metadata resource", len);
+                     "metadata resource", subdir_offset);
                return WIMLIB_ERR_NOMEM;
        }