[LibOS] Fix pointer alignment issue in __hash()

The issue was found by UBSAN.
gramineproject · Jan 19, 2021 · eb3c58f · eb3c58f
1 parent b534b45
commit eb3c58f
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/LibOS/shim/src/fs/shim_fs_hash.c b/LibOS/shim/src/fs/shim_fs_hash.c
@@ -10,9 +10,11 @@
 
 static HASHTYPE __hash(const char* p, size_t len) {
     HASHTYPE hash = 0;
+    HASHTYPE tmp;
 
     for (; len >= sizeof(hash); p += sizeof(hash), len -= sizeof(hash)) {
-        hash += *((HASHTYPE*)p);
+        memcpy(&tmp, p, sizeof(tmp)); /* avoid pointer alignment issues */
+        hash += tmp;
         hash *= 9;
     }