1 files changed, 83 insertions, 0 deletions
diff --git a/lib/isc/safe.c b/lib/isc/safe.c
new file mode 100644
index 0000000..7a464b6
--- /dev/null
+++ b/lib/isc/safe.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+#include <config.h>
+
+#include <stdbool.h>
+
+#include <isc/safe.h>
+#include <isc/string.h>
+#include <isc/util.h>
+
+#ifdef WIN32
+#include <windows.h>
+#endif
+
+#ifdef _MSC_VER
+#pragma optimize("", off)
+#endif
+
+bool
+isc_safe_memequal(const void *s1, const void *s2, size_t n) {
+	uint8_t acc = 0;
+
+	if (n != 0U) {
+		const uint8_t *p1 = s1, *p2 = s2;
+
+		do {
+			acc |= *p1++ ^ *p2++;
+		} while (--n != 0U);
+	}
+	return (acc == 0);
+}
+
+
+int
+isc_safe_memcompare(const void *b1, const void *b2, size_t len) {
+	const unsigned char *p1 = b1, *p2 = b2;
+	size_t i;
+	int res = 0, done = 0;
+
+	for (i = 0; i < len; i++) {
+		/* lt is -1 if p1[i] < p2[i]; else 0. */
+		int lt = (p1[i] - p2[i]) >> CHAR_BIT;
+
+		/* gt is -1 if p1[i] > p2[i]; else 0. */
+		int gt = (p2[i] - p1[i]) >> CHAR_BIT;
+
+		/* cmp is 1 if p1[i] > p2[i]; -1 if p1[i] < p2[i]; else 0. */
+		int cmp = lt - gt;
+
+		/* set res = cmp if !done. */
+		res |= cmp & ~done;
+
+		/* set done if p1[i] != p2[i]. */
+		done |= lt | gt;
+	}
+
+	return (res);
+}
+
+void
+isc_safe_memwipe(void *ptr, size_t len) {
+	if (ISC_UNLIKELY(ptr == NULL || len == 0))
+		return;
+
+#ifdef WIN32
+	SecureZeroMemory(ptr, len);
+#elif HAVE_EXPLICIT_BZERO
+	explicit_bzero(ptr, len);
+#else
+	memset(ptr, 0, len);
+#endif
+}