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-rw-r--r--src/support/allocators/secure.h62
-rw-r--r--src/support/allocators/zeroafterfree.h48
-rw-r--r--src/support/pagelocker.cpp70
-rw-r--r--src/support/pagelocker.h178
4 files changed, 358 insertions, 0 deletions
diff --git a/src/support/allocators/secure.h b/src/support/allocators/secure.h
new file mode 100644
index 0000000000..7a74d87bb4
--- /dev/null
+++ b/src/support/allocators/secure.h
@@ -0,0 +1,62 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2013 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_ALLOCATORS_SECURE_H
+#define BITCOIN_ALLOCATORS_SECURE_H
+
+#include "support/pagelocker.h"
+
+#include <string>
+
+//
+// Allocator that locks its contents from being paged
+// out of memory and clears its contents before deletion.
+//
+template <typename T>
+struct secure_allocator : public std::allocator<T> {
+ // MSVC8 default copy constructor is broken
+ typedef std::allocator<T> base;
+ typedef typename base::size_type size_type;
+ typedef typename base::difference_type difference_type;
+ typedef typename base::pointer pointer;
+ typedef typename base::const_pointer const_pointer;
+ typedef typename base::reference reference;
+ typedef typename base::const_reference const_reference;
+ typedef typename base::value_type value_type;
+ secure_allocator() throw() {}
+ secure_allocator(const secure_allocator& a) throw() : base(a) {}
+ template <typename U>
+ secure_allocator(const secure_allocator<U>& a) throw() : base(a)
+ {
+ }
+ ~secure_allocator() throw() {}
+ template <typename _Other>
+ struct rebind {
+ typedef secure_allocator<_Other> other;
+ };
+
+ T* allocate(std::size_t n, const void* hint = 0)
+ {
+ T* p;
+ p = std::allocator<T>::allocate(n, hint);
+ if (p != NULL)
+ LockedPageManager::Instance().LockRange(p, sizeof(T) * n);
+ return p;
+ }
+
+ void deallocate(T* p, std::size_t n)
+ {
+ if (p != NULL) {
+ memory_cleanse(p, sizeof(T) * n);
+ LockedPageManager::Instance().UnlockRange(p, sizeof(T) * n);
+ }
+ std::allocator<T>::deallocate(p, n);
+ }
+};
+
+// This is exactly like std::string, but with a custom allocator.
+typedef std::basic_string<char, std::char_traits<char>, secure_allocator<char> > SecureString;
+
+#endif // BITCOIN_ALLOCATORS_SECURE_H
diff --git a/src/support/allocators/zeroafterfree.h b/src/support/allocators/zeroafterfree.h
new file mode 100644
index 0000000000..b01fcd088b
--- /dev/null
+++ b/src/support/allocators/zeroafterfree.h
@@ -0,0 +1,48 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2013 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_ALLOCATORS_ZEROAFTERFREE_H
+#define BITCOIN_ALLOCATORS_ZEROAFTERFREE_H
+
+#include "support/cleanse.h"
+
+#include <memory>
+#include <vector>
+
+template <typename T>
+struct zero_after_free_allocator : public std::allocator<T> {
+ // MSVC8 default copy constructor is broken
+ typedef std::allocator<T> base;
+ typedef typename base::size_type size_type;
+ typedef typename base::difference_type difference_type;
+ typedef typename base::pointer pointer;
+ typedef typename base::const_pointer const_pointer;
+ typedef typename base::reference reference;
+ typedef typename base::const_reference const_reference;
+ typedef typename base::value_type value_type;
+ zero_after_free_allocator() throw() {}
+ zero_after_free_allocator(const zero_after_free_allocator& a) throw() : base(a) {}
+ template <typename U>
+ zero_after_free_allocator(const zero_after_free_allocator<U>& a) throw() : base(a)
+ {
+ }
+ ~zero_after_free_allocator() throw() {}
+ template <typename _Other>
+ struct rebind {
+ typedef zero_after_free_allocator<_Other> other;
+ };
+
+ void deallocate(T* p, std::size_t n)
+ {
+ if (p != NULL)
+ memory_cleanse(p, sizeof(T) * n);
+ std::allocator<T>::deallocate(p, n);
+ }
+};
+
+// Byte-vector that clears its contents before deletion.
+typedef std::vector<char, zero_after_free_allocator<char> > CSerializeData;
+
+#endif // BITCOIN_ALLOCATORS_ZEROAFTERFREE_H
diff --git a/src/support/pagelocker.cpp b/src/support/pagelocker.cpp
new file mode 100644
index 0000000000..440e0a5193
--- /dev/null
+++ b/src/support/pagelocker.cpp
@@ -0,0 +1,70 @@
+// Copyright (c) 2009-2013 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "support/pagelocker.h"
+
+#if defined(HAVE_CONFIG_H)
+#include "config/bitcoin-config.h"
+#endif
+
+#ifdef WIN32
+#ifdef _WIN32_WINNT
+#undef _WIN32_WINNT
+#endif
+#define _WIN32_WINNT 0x0501
+#define WIN32_LEAN_AND_MEAN 1
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+#include <windows.h>
+// This is used to attempt to keep keying material out of swap
+// Note that VirtualLock does not provide this as a guarantee on Windows,
+// but, in practice, memory that has been VirtualLock'd almost never gets written to
+// the pagefile except in rare circumstances where memory is extremely low.
+#else
+#include <sys/mman.h>
+#include <limits.h> // for PAGESIZE
+#include <unistd.h> // for sysconf
+#endif
+
+LockedPageManager* LockedPageManager::_instance = NULL;
+boost::once_flag LockedPageManager::init_flag = BOOST_ONCE_INIT;
+
+/** Determine system page size in bytes */
+static inline size_t GetSystemPageSize()
+{
+ size_t page_size;
+#if defined(WIN32)
+ SYSTEM_INFO sSysInfo;
+ GetSystemInfo(&sSysInfo);
+ page_size = sSysInfo.dwPageSize;
+#elif defined(PAGESIZE) // defined in limits.h
+ page_size = PAGESIZE;
+#else // assume some POSIX OS
+ page_size = sysconf(_SC_PAGESIZE);
+#endif
+ return page_size;
+}
+
+bool MemoryPageLocker::Lock(const void* addr, size_t len)
+{
+#ifdef WIN32
+ return VirtualLock(const_cast<void*>(addr), len) != 0;
+#else
+ return mlock(addr, len) == 0;
+#endif
+}
+
+bool MemoryPageLocker::Unlock(const void* addr, size_t len)
+{
+#ifdef WIN32
+ return VirtualUnlock(const_cast<void*>(addr), len) != 0;
+#else
+ return munlock(addr, len) == 0;
+#endif
+}
+
+LockedPageManager::LockedPageManager() : LockedPageManagerBase<MemoryPageLocker>(GetSystemPageSize())
+{
+}
diff --git a/src/support/pagelocker.h b/src/support/pagelocker.h
new file mode 100644
index 0000000000..964be1aec4
--- /dev/null
+++ b/src/support/pagelocker.h
@@ -0,0 +1,178 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2013 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_ALLOCATORS_PAGELOCKER_H
+#define BITCOIN_ALLOCATORS_PAGELOCKER_H
+
+#include "support/cleanse.h"
+
+#include <map>
+
+#include <boost/thread/mutex.hpp>
+#include <boost/thread/once.hpp>
+
+/**
+ * Thread-safe class to keep track of locked (ie, non-swappable) memory pages.
+ *
+ * Memory locks do not stack, that is, pages which have been locked several times by calls to mlock()
+ * will be unlocked by a single call to munlock(). This can result in keying material ending up in swap when
+ * those functions are used naively. This class simulates stacking memory locks by keeping a counter per page.
+ *
+ * @note By using a map from each page base address to lock count, this class is optimized for
+ * small objects that span up to a few pages, mostly smaller than a page. To support large allocations,
+ * something like an interval tree would be the preferred data structure.
+ */
+template <class Locker>
+class LockedPageManagerBase
+{
+public:
+ LockedPageManagerBase(size_t page_size) : page_size(page_size)
+ {
+ // Determine bitmask for extracting page from address
+ assert(!(page_size & (page_size - 1))); // size must be power of two
+ page_mask = ~(page_size - 1);
+ }
+
+ ~LockedPageManagerBase()
+ {
+ assert(this->GetLockedPageCount() == 0);
+ }
+
+
+ // For all pages in affected range, increase lock count
+ void LockRange(void* p, size_t size)
+ {
+ boost::mutex::scoped_lock lock(mutex);
+ if (!size)
+ return;
+ const size_t base_addr = reinterpret_cast<size_t>(p);
+ const size_t start_page = base_addr & page_mask;
+ const size_t end_page = (base_addr + size - 1) & page_mask;
+ for (size_t page = start_page; page <= end_page; page += page_size) {
+ Histogram::iterator it = histogram.find(page);
+ if (it == histogram.end()) // Newly locked page
+ {
+ locker.Lock(reinterpret_cast<void*>(page), page_size);
+ histogram.insert(std::make_pair(page, 1));
+ } else // Page was already locked; increase counter
+ {
+ it->second += 1;
+ }
+ }
+ }
+
+ // For all pages in affected range, decrease lock count
+ void UnlockRange(void* p, size_t size)
+ {
+ boost::mutex::scoped_lock lock(mutex);
+ if (!size)
+ return;
+ const size_t base_addr = reinterpret_cast<size_t>(p);
+ const size_t start_page = base_addr & page_mask;
+ const size_t end_page = (base_addr + size - 1) & page_mask;
+ for (size_t page = start_page; page <= end_page; page += page_size) {
+ Histogram::iterator it = histogram.find(page);
+ assert(it != histogram.end()); // Cannot unlock an area that was not locked
+ // Decrease counter for page, when it is zero, the page will be unlocked
+ it->second -= 1;
+ if (it->second == 0) // Nothing on the page anymore that keeps it locked
+ {
+ // Unlock page and remove the count from histogram
+ locker.Unlock(reinterpret_cast<void*>(page), page_size);
+ histogram.erase(it);
+ }
+ }
+ }
+
+ // Get number of locked pages for diagnostics
+ int GetLockedPageCount()
+ {
+ boost::mutex::scoped_lock lock(mutex);
+ return histogram.size();
+ }
+
+private:
+ Locker locker;
+ boost::mutex mutex;
+ size_t page_size, page_mask;
+ // map of page base address to lock count
+ typedef std::map<size_t, int> Histogram;
+ Histogram histogram;
+};
+
+
+/**
+ * OS-dependent memory page locking/unlocking.
+ * Defined as policy class to make stubbing for test possible.
+ */
+class MemoryPageLocker
+{
+public:
+ /** Lock memory pages.
+ * addr and len must be a multiple of the system page size
+ */
+ bool Lock(const void* addr, size_t len);
+ /** Unlock memory pages.
+ * addr and len must be a multiple of the system page size
+ */
+ bool Unlock(const void* addr, size_t len);
+};
+
+/**
+ * Singleton class to keep track of locked (ie, non-swappable) memory pages, for use in
+ * std::allocator templates.
+ *
+ * Some implementations of the STL allocate memory in some constructors (i.e., see
+ * MSVC's vector<T> implementation where it allocates 1 byte of memory in the allocator.)
+ * Due to the unpredictable order of static initializers, we have to make sure the
+ * LockedPageManager instance exists before any other STL-based objects that use
+ * secure_allocator are created. So instead of having LockedPageManager also be
+ * static-initialized, it is created on demand.
+ */
+class LockedPageManager : public LockedPageManagerBase<MemoryPageLocker>
+{
+public:
+ static LockedPageManager& Instance()
+ {
+ boost::call_once(LockedPageManager::CreateInstance, LockedPageManager::init_flag);
+ return *LockedPageManager::_instance;
+ }
+
+private:
+ LockedPageManager();
+
+ static void CreateInstance()
+ {
+ // Using a local static instance guarantees that the object is initialized
+ // when it's first needed and also deinitialized after all objects that use
+ // it are done with it. I can think of one unlikely scenario where we may
+ // have a static deinitialization order/problem, but the check in
+ // LockedPageManagerBase's destructor helps us detect if that ever happens.
+ static LockedPageManager instance;
+ LockedPageManager::_instance = &instance;
+ }
+
+ static LockedPageManager* _instance;
+ static boost::once_flag init_flag;
+};
+
+//
+// Functions for directly locking/unlocking memory objects.
+// Intended for non-dynamically allocated structures.
+//
+template <typename T>
+void LockObject(const T& t)
+{
+ LockedPageManager::Instance().LockRange((void*)(&t), sizeof(T));
+}
+
+template <typename T>
+void UnlockObject(const T& t)
+{
+ memory_cleanse((void*)(&t), sizeof(T));
+ LockedPageManager::Instance().UnlockRange((void*)(&t), sizeof(T));
+}
+
+#endif // BITCOIN_ALLOCATORS_PAGELOCKER_H
generated by cgit v1.2.3 (git 2.26.2) at 2024-11-02 07:15:20 +0000