4 files changed, 89 insertions, 22 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7d6bfe4c..402b74e0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -204,7 +204,11 @@ apidsl(
   toxcore/crypto_core.api.h)
 add_module(toxcrypto
   toxcore/crypto_core.c
-  toxcore/crypto_core.h)
+  toxcore/crypto_core.h
+  toxcore/crypto_core_mem.c)
+include(CheckFunctionExists)
+check_function_exists(explicit_bzero HAVE_EXPLICIT_BZERO)
+check_function_exists(memset_s HAVE_MEMSET_S)
 target_link_modules(toxcrypto ${LIBSODIUM_LIBRARIES})
 if(WIN32)
   target_link_modules(toxcrypto ws2_32) # for htonl
diff --git a/toxcore/Makefile.inc b/toxcore/Makefile.inc
index 84e24ebd..b81087f0 100644
--- a/toxcore/Makefile.inc
+++ b/toxcore/Makefile.inc
@@ -11,6 +11,7 @@ libtoxcore_la_SOURCES = ../toxcore/DHT.h \
                         ../toxcore/network.c \
                         ../toxcore/crypto_core.h \
                         ../toxcore/crypto_core.c \
+                        ../toxcore/crypto_core_mem.c \
                         ../toxcore/ping_array.h \
                         ../toxcore/ping_array.c \
                         ../toxcore/net_crypto.h \
diff --git a/toxcore/crypto_core.c b/toxcore/crypto_core.c
index d3a3e1fc..4d536cf7 100644
--- a/toxcore/crypto_core.c
+++ b/toxcore/crypto_core.c
@@ -268,27 +268,6 @@ void crypto_sha512(uint8_t *hash, const uint8_t *data, size_t length)
     crypto_hash_sha512(hash, data, length);
 }
 
-void crypto_memzero(void *data, size_t length)
-{
-#ifdef VANILLA_NACL
-    /* TODO(c-toxcore#347): this is insecure. We need to provide our own
-     * secure memzero/memcmp for NaCL. */
-    memset(data, 0, length);
-#else
-    sodium_memzero(data, length);
-#endif
-}
-
-int32_t crypto_memcmp(const void *p1, const void *p2, size_t length)
-{
-#ifdef VANILLA_NACL
-    /* TODO(c-toxcore#347): Implement secure memcmp. */
-    return memcmp(p1, p2, length);
-#else
-    return sodium_memcmp(p1, p2, length);
-#endif
-}
-
 void random_bytes(uint8_t *data, size_t length)
 {
     randombytes(data, length);
diff --git a/toxcore/crypto_core_mem.c b/toxcore/crypto_core_mem.c
new file mode 100644
index 00000000..8d469986
--- /dev/null
+++ b/toxcore/crypto_core_mem.c
@@ -0,0 +1,83 @@
+/*
+ * ISC License
+ *
+ * Copyright (c) 2013-2016
+ * Frank Denis <j at pureftpd dot org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+
+#include "crypto_core.h"
+
+#ifndef VANILLA_NACL
+/* We use libsodium by default. */
+#include <sodium.h>
+#else
+#if defined(_WIN32) || defined(__WIN32__) || defined(WIN32)
+#include <windows.h>
+#include <wincrypt.h>
+#endif
+#endif
+
+
+void crypto_memzero(void *data, size_t length)
+{
+#ifndef VANILLA_NACL
+    sodium_memzero(data, length);
+#else
+#ifdef _WIN32
+    SecureZeroMemory(pnt, len);
+#elif defined(HAVE_MEMSET_S)
+
+    errno_t code = memset_s(data, (rsize_t) length, 0, (rsize_t) length)
+
+    if (len > 0U && code != 0) {
+        abort(); /* LCOV_EXCL_LINE */
+    }
+
+#elif defined(HAVE_EXPLICIT_BZERO)
+    explicit_bzero(data, length);
+#else
+    volatile unsigned char *volatile pnt =
+        (volatile unsigned char *volatile) data;
+    size_t i = (size_t) 0U;
+
+    while (i < length) {
+        pnt[i++] = 0U;
+    }
+
+#endif
+#endif
+}
+
+int32_t crypto_memcmp(const void *p1, const void *p2, size_t length)
+{
+#ifndef VANILLA_NACL
+    return sodium_memcmp(p1, p2, length);
+#else
+    const volatile unsigned char *volatile b1 =
+        (const volatile unsigned char *volatile) p1;
+    const volatile unsigned char *volatile b2 =
+        (const volatile unsigned char *volatile) p2;
+
+    size_t i;
+    unsigned char d = (unsigned char) 0U;
+
+    for (i = 0U; i < length; i++) {
+        d |= b1[i] ^ b2[i];
+    }
+
+    return (1 & ((d - 1) >> 8)) - 1;
+#endif
+}