Add wrappers for calloc style functions with size overflow checking

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 54 insertions, 0 deletions

diff --git a/lib/util/alloc.c b/lib/util/alloc.c
new file mode 100644
index 0000000..2d748a7
--- /dev/null
+++ b/lib/util/alloc.c
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * alloc.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "util.h"
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <errno.h>
+
+void *alloc_flex(size_t base_size, size_t item_size, size_t nmemb)
+{
+	size_t size;
+
+	if (SZ_MUL_OV(nmemb, item_size, &size)) {
+		errno = EOVERFLOW;
+		return NULL;
+	}
+
+	if (SZ_ADD_OV(base_size, size, &size)) {
+		errno = EOVERFLOW;
+		return NULL;
+	}
+
+	return calloc(1, size);
+}
+
+void *alloc_array(size_t item_size, size_t nmemb)
+{
+	size_t size;
+
+	if (SZ_MUL_OV(nmemb, item_size, &size)) {
+		errno = EOVERFLOW;
+		return NULL;
+	}
+
+	return calloc(1, size);
+}
+
+void *alloc_string(size_t len)
+{
+	size_t size;
+
+	if (SZ_ADD_OV(len, 1, &size)) {
+		errno = EOVERFLOW;
+		return NULL;
+	}
+
+	return calloc(1, len);
+}