From cbec7032ee36346649fc5ebecc4b1c01f01178f1 Mon Sep 17 00:00:00 2001
From: Scarlett <scarlett@xavin.net>
Date: Thu, 15 Jan 2015 19:38:11 +0900
Subject: Add overflow detection

Origin: http://marc.info/?l=openbsd-ports&m=142090828929750&w=2

* main.c: Call exit(1) when out of memory to avoid dereferencing null
pointers when gc's malloc fails.

* alloc.h: Replacements for w3m's allocation macros which add
overflow detection and concentrate the macros in one file.

* indep.h, libwc/charset.c, libwc/status.c, matrix.c: Use the
overflow-detecting allocation macros from alloc.h.
---
 alloc.h | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 alloc.h

(limited to 'alloc.h')

diff --git a/alloc.h b/alloc.h
new file mode 100644
index 0000000..7d23414
--- /dev/null
+++ b/alloc.h
@@ -0,0 +1,39 @@
+/*
+ * by Scarlett. public domain.
+ * replacements for w3m's allocation macros which add overflow
+ * detection and concentrate the macros in one file
+ */
+#ifndef W3_ALLOC_H
+#define W3_ALLOC_H
+#include <gc.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <limits.h>
+
+static inline size_t
+z_mult_no_oflow_(size_t n, size_t size)
+{
+	if (size != 0 && n > SIZE_MAX / size) {
+		fprintf(stderr,
+		    "w3m: overflow in malloc, %zu*%zu\n", n, size);
+		exit(1);
+	}
+	return n * size;
+}
+
+#define New(type) \
+	(GC_MALLOC(sizeof(type)))
+
+#define NewAtom(type) \
+	(GC_MALLOC_ATOMIC(sizeof(type)))
+
+#define New_N(type, n) \
+	(GC_MALLOC(z_mult_no_oflow_((n), sizeof(type))))
+
+#define NewAtom_N(type, n) \
+	(GC_MALLOC_ATOMIC(z_mult_no_oflow_((n), sizeof(type))))
+
+#define New_Reuse(type, ptr, n) \
+	(GC_REALLOC((ptr), z_mult_no_oflow_((n), sizeof(type))))
+
+#endif /* W3_ALLOC_H */
-- 
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