move memwipe to epee to avoid common<->crypto circular dependencies

3 files changed, 195 insertions, 1 deletions

diff --git a/contrib/epee/include/memwipe.h b/contrib/epee/include/memwipe.h
new file mode 100644
index 000000000..c3b4ce8ab
--- /dev/null
+++ b/contrib/epee/include/memwipe.h
@@ -0,0 +1,84 @@
+// Copyright (c) 2017, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// 
+// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
+
+#pragma once
+
+#ifdef __cplusplus
+#include <array>
+
+extern "C" {
+#endif
+
+void *memwipe(void *src, size_t n);
+
+#ifdef __cplusplus
+}
+#endif
+
+#ifdef __cplusplus
+namespace tools {
+
+  /// Scrubs data in the contained type upon destruction.
+  ///
+  /// Primarily useful for making sure that private keys don't stick around in
+  /// memory after the objects that held them have gone out of scope.
+  template <class T>
+  struct scrubbed : public T {
+    using type = T;
+
+    ~scrubbed() {
+      scrub();
+    }
+
+    /// Destroy the contents of the contained type.
+    void scrub() {
+      static_assert(std::is_pod<T>::value,
+                    "T cannot be auto-scrubbed. T must be POD.");
+      static_assert(std::is_trivially_destructible<T>::value,
+                    "T cannot be auto-scrubbed. T must be trivially destructable.");
+      memwipe(this, sizeof(T));
+    }
+  };
+
+  template <class T, size_t N>
+  using scrubbed_arr = scrubbed<std::array<T, N>>;
+} // namespace tools
+
+// Partial specialization for std::is_pod<tools::scrubbed<T>> so that it can
+// pretend to be the containted type in those contexts.
+namespace std
+{
+  template<class t_scrubbee>
+  struct is_pod<tools::scrubbed<t_scrubbee>> {
+    static const bool value = is_pod<t_scrubbee>::value;
+  };
+}
+
+#endif // __cplusplus
diff --git a/contrib/epee/src/CMakeLists.txt b/contrib/epee/src/CMakeLists.txt
index ee118724d..9d104ceeb 100644
--- a/contrib/epee/src/CMakeLists.txt
+++ b/contrib/epee/src/CMakeLists.txt
@@ -26,12 +26,16 @@
 # STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 # THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-add_library(epee STATIC hex.cpp http_auth.cpp mlog.cpp net_utils_base.cpp string_tools.cpp wipeable_string.cpp
+add_library(epee STATIC hex.cpp http_auth.cpp mlog.cpp net_utils_base.cpp string_tools.cpp wipeable_string.cpp memwipe.c
     connection_basic.cpp network_throttle.cpp network_throttle-detail.cpp)
 if (USE_READLINE AND GNU_READLINE_FOUND)
   add_library(epee_readline STATIC readline_buffer.cpp)
 endif()
 
+if(HAVE_C11)
+SET_PROPERTY(SOURCE memwipe.c PROPERTY COMPILE_FLAGS -std=c11)
+endif()
+
 # Build and install libepee if we're building for GUI
 if (BUILD_GUI_DEPS)
     if(IOS)
diff --git a/contrib/epee/src/memwipe.c b/contrib/epee/src/memwipe.c
new file mode 100644
index 000000000..da7e9f346
--- /dev/null
+++ b/contrib/epee/src/memwipe.c
@@ -0,0 +1,106 @@
+// Copyright (c) 2017, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Parts of this file Copyright (c) 2009-2015 The Bitcoin Core developers
+
+#define __STDC_WANT_LIB_EXT1__ 1
+#include <string.h>
+#include <stdlib.h>
+#ifdef HAVE_EXPLICIT_BZERO
+#include <strings.h>
+#endif
+#include "memwipe.h"
+
+#if defined(_MSC_VER)
+#define SCARECROW \
+    __asm;
+#else
+#define SCARECROW \
+    __asm__ __volatile__("" : : "r"(ptr) : "memory");
+#endif
+
+#ifdef HAVE_MEMSET_S
+
+void *memwipe(void *ptr, size_t n)
+{
+  if (memset_s(ptr, n, 0, n))
+  {
+    abort();
+  }
+  SCARECROW // might as well...
+  return ptr;
+}
+
+#elif defined HAVE_EXPLICIT_BZERO
+
+void *memwipe(void *ptr, size_t n)
+{
+  explicit_bzero(ptr, n);
+  SCARECROW
+  return ptr;
+}
+
+#else
+
+/* The memory_cleanse implementation is taken from Bitcoin */
+
+/* Compilers have a bad habit of removing "superfluous" memset calls that
+ * are trying to zero memory. For example, when memset()ing a buffer and
+ * then free()ing it, the compiler might decide that the memset is
+ * unobservable and thus can be removed.
+ *
+ * Previously we used OpenSSL which tried to stop this by a) implementing
+ * memset in assembly on x86 and b) putting the function in its own file
+ * for other platforms.
+ *
+ * This change removes those tricks in favour of using asm directives to
+ * scare the compiler away. As best as our compiler folks can tell, this is
+ * sufficient and will continue to be so.
+ *
+ * Adam Langley <agl@google.com>
+ * Commit: ad1907fe73334d6c696c8539646c21b11178f20f
+ * BoringSSL (LICENSE: ISC)
+ */
+static void memory_cleanse(void *ptr, size_t len)
+{
+    memset(ptr, 0, len);
+
+    /* As best as we can tell, this is sufficient to break any optimisations that
+       might try to eliminate "superfluous" memsets. If there's an easy way to
+       detect memset_s, it would be better to use that. */
+    SCARECROW
+}
+
+void *memwipe(void *ptr, size_t n)
+{
+  memory_cleanse(ptr, n);
+  SCARECROW
+  return ptr;
+}
+
+#endif