Crypto++  8.3
Free C++ class library of cryptographic schemes
secblock.h
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1 // secblock.h - originally written and placed in the public domain by Wei Dai
2 
3 /// \file secblock.h
4 /// \brief Classes and functions for secure memory allocations.
5 
6 #ifndef CRYPTOPP_SECBLOCK_H
7 #define CRYPTOPP_SECBLOCK_H
8 
9 #include "config.h"
10 #include "allocate.h"
11 #include "misc.h"
12 #include "stdcpp.h"
13 
14 #if CRYPTOPP_MSC_VERSION
15 # pragma warning(push)
16 # pragma warning(disable: 4231 4275 4700)
17 # if (CRYPTOPP_MSC_VERSION >= 1400)
18 # pragma warning(disable: 6011 6386 28193)
19 # endif
20 #endif
21 
22 NAMESPACE_BEGIN(CryptoPP)
23 
24 // ************** secure memory allocation ***************
25 
26 /// \brief Base class for all allocators used by SecBlock
27 /// \tparam T the class or type
28 template<class T>
30 {
31 public:
32  typedef T value_type;
33  typedef size_t size_type;
34  typedef std::ptrdiff_t difference_type;
35  typedef T * pointer;
36  typedef const T * const_pointer;
37  typedef T & reference;
38  typedef const T & const_reference;
39 
40  pointer address(reference r) const {return (&r);}
41  const_pointer address(const_reference r) const {return (&r); }
42  void construct(pointer p, const T& val) {new (p) T(val);}
43  void destroy(pointer p) {CRYPTOPP_UNUSED(p); p->~T();}
44 
45  /// \brief Returns the maximum number of elements the allocator can provide
46  /// \details <tt>ELEMS_MAX</tt> is the maximum number of elements the
47  /// <tt>Allocator</tt> can provide. The value of <tt>ELEMS_MAX</tt> is
48  /// <tt>SIZE_MAX/sizeof(T)</tt>. <tt>std::numeric_limits</tt> was avoided
49  /// due to lack of <tt>constexpr</tt>-ness in C++03 and below.
50  /// \note In C++03 and below <tt>ELEMS_MAX</tt> is a static data member of type
51  /// <tt>size_type</tt>. In C++11 and above <tt>ELEMS_MAX</tt> is an <tt>enum</tt>
52  /// inheriting from <tt>size_type</tt>. In both cases <tt>ELEMS_MAX</tt> can be
53  /// used before objects are fully constructed, and it does not suffer the
54  /// limitations of class methods like <tt>max_size</tt>.
55  /// \sa <A HREF="http://github.com/weidai11/cryptopp/issues/346">Issue 346/CVE-2016-9939</A>
56  /// \since Crypto++ 6.0
57 #if defined(CRYPTOPP_DOXYGEN_PROCESSING)
58  static const size_type ELEMS_MAX = ...;
59 #elif defined(_MSC_VER) && (_MSC_VER <= 1400)
60  static const size_type ELEMS_MAX = (~(size_type)0)/sizeof(T);
61 #elif defined(CRYPTOPP_CXX11_STRONG_ENUM)
62  enum : size_type {ELEMS_MAX = SIZE_MAX/sizeof(T)};
63 #else
64  static const size_type ELEMS_MAX = SIZE_MAX/sizeof(T);
65 #endif
66 
67  /// \brief Returns the maximum number of elements the allocator can provide
68  /// \return the maximum number of elements the allocator can provide
69  /// \details Internally, preprocessor macros are used rather than std::numeric_limits
70  /// because the latter is not a constexpr. Some compilers, like Clang, do not
71  /// optimize it well under all circumstances. Compilers like GCC, ICC and MSVC appear
72  /// to optimize it well in either form.
73  CRYPTOPP_CONSTEXPR size_type max_size() const {return ELEMS_MAX;}
74 
75 #if defined(__SUNPRO_CC)
76  // https://github.com/weidai11/cryptopp/issues/770
77  // and https://stackoverflow.com/q/53999461/608639
78  CRYPTOPP_CONSTEXPR size_type max_size(size_type n) const {return SIZE_MAX/n;}
79 #endif
80 
81 #if defined(CRYPTOPP_CXX11_VARIADIC_TEMPLATES) || defined(CRYPTOPP_DOXYGEN_PROCESSING)
82 
83  /// \brief Constructs a new V using variadic arguments
84  /// \tparam V the type to be forwarded
85  /// \tparam Args the arguments to be forwarded
86  /// \param ptr pointer to type V
87  /// \param args variadic arguments
88  /// \details This is a C++11 feature. It is available when CRYPTOPP_CXX11_VARIADIC_TEMPLATES
89  /// is defined. The define is controlled by compiler versions detected in config.h.
90  template<typename V, typename... Args>
91  void construct(V* ptr, Args&&... args) {::new ((void*)ptr) V(std::forward<Args>(args)...);}
92 
93  /// \brief Destroys an V constructed with variadic arguments
94  /// \tparam V the type to be forwarded
95  /// \details This is a C++11 feature. It is available when CRYPTOPP_CXX11_VARIADIC_TEMPLATES
96  /// is defined. The define is controlled by compiler versions detected in config.h.
97  template<typename V>
98  void destroy(V* ptr) {if (ptr) ptr->~V();}
99 
100 #endif
101 
102 protected:
103 
104  /// \brief Verifies the allocator can satisfy a request based on size
105  /// \param size the size of the allocation, in elements
106  /// \throw InvalidArgument
107  /// \details CheckSize verifies the number of elements requested is valid.
108  /// \details If size is greater than max_size(), then InvalidArgument is thrown.
109  /// The library throws InvalidArgument if the size is too large to satisfy.
110  /// \details Internally, preprocessor macros are used rather than std::numeric_limits
111  /// because the latter is not a constexpr. Some compilers, like Clang, do not
112  /// optimize it well under all circumstances. Compilers like GCC, ICC and MSVC appear
113  /// to optimize it well in either form.
114  /// \details The <tt>sizeof(T) != 1</tt> in the condition attempts to help the
115  /// compiler optimize the check for byte types. Coverity findings for
116  /// CONSTANT_EXPRESSION_RESULT were generated without it. For byte types,
117  /// size never exceeded ELEMS_MAX but the code was not removed.
118  /// \note size is the count of elements, and not the number of bytes
119  static void CheckSize(size_t size)
120  {
121  // Squash MSC C4100 warning for size. Also see commit 42b7c4ea5673.
122  CRYPTOPP_UNUSED(size);
123  // C++ throws std::bad_alloc (C++03) or std::bad_array_new_length (C++11) here.
124  if (sizeof(T) != 1 && size > ELEMS_MAX)
125  throw InvalidArgument("AllocatorBase: requested size would cause integer overflow");
126  }
127 };
128 
129 #define CRYPTOPP_INHERIT_ALLOCATOR_TYPES \
130 typedef typename AllocatorBase<T>::value_type value_type;\
131 typedef typename AllocatorBase<T>::size_type size_type;\
132 typedef typename AllocatorBase<T>::difference_type difference_type;\
133 typedef typename AllocatorBase<T>::pointer pointer;\
134 typedef typename AllocatorBase<T>::const_pointer const_pointer;\
135 typedef typename AllocatorBase<T>::reference reference;\
136 typedef typename AllocatorBase<T>::const_reference const_reference;
137 
138 /// \brief Reallocation function
139 /// \tparam T the class or type
140 /// \tparam A the class or type's allocator
141 /// \param alloc the allocator
142 /// \param oldPtr the previous allocation
143 /// \param oldSize the size of the previous allocation
144 /// \param newSize the new, requested size
145 /// \param preserve flag that indicates if the old allocation should be preserved
146 /// \note oldSize and newSize are the count of elements, and not the
147 /// number of bytes.
148 template <class T, class A>
149 typename A::pointer StandardReallocate(A& alloc, T *oldPtr, typename A::size_type oldSize, typename A::size_type newSize, bool preserve)
150 {
151  // Avoid assert on pointer in reallocate. SecBlock regularly uses NULL
152  // pointers rather returning non-NULL 0-sized pointers.
153  if (oldSize == newSize)
154  return oldPtr;
155 
156  if (preserve)
157  {
158  typename A::pointer newPointer = alloc.allocate(newSize, NULLPTR);
159  const typename A::size_type copySize = STDMIN(oldSize, newSize) * sizeof(T);
160 
161  if (oldPtr && newPointer)
162  memcpy_s(newPointer, copySize, oldPtr, copySize);
163 
164  if (oldPtr)
165  alloc.deallocate(oldPtr, oldSize);
166 
167  return newPointer;
168  }
169  else
170  {
171  if (oldPtr)
172  alloc.deallocate(oldPtr, oldSize);
173 
174  return alloc.allocate(newSize, NULLPTR);
175  }
176 }
177 
178 /// \brief Allocates a block of memory with cleanup
179 /// \tparam T class or type
180 /// \tparam T_Align16 boolean that determines whether allocations should be aligned on a 16-byte boundary
181 /// \details If T_Align16 is true, then AllocatorWithCleanup calls AlignedAllocate()
182 /// for memory allocations. If T_Align16 is false, then AllocatorWithCleanup() calls
183 /// UnalignedAllocate() for memory allocations.
184 /// \details Template parameter T_Align16 is effectively controlled by cryptlib.h and mirrors
185 /// CRYPTOPP_BOOL_ALIGN16. CRYPTOPP_BOOL_ALIGN16 is often used as the template parameter.
186 template <class T, bool T_Align16 = false>
188 {
189 public:
190  CRYPTOPP_INHERIT_ALLOCATOR_TYPES
191 
192  /// \brief Allocates a block of memory
193  /// \param ptr the size of the allocation
194  /// \param size the size of the allocation, in elements
195  /// \return a memory block
196  /// \throw InvalidArgument
197  /// \details allocate() first checks the size of the request. If it is non-0
198  /// and less than max_size(), then an attempt is made to fulfill the request
199  /// using either AlignedAllocate() or UnalignedAllocate(). AlignedAllocate() is
200  /// used if T_Align16 is true. UnalignedAllocate() used if T_Align16 is false.
201  /// \details This is the C++ *Placement New* operator. ptr is not used, and the
202  /// function asserts in Debug builds if ptr is non-NULL.
203  /// \sa CallNewHandler() for the methods used to recover from a failed
204  /// allocation attempt.
205  /// \note size is the count of elements, and not the number of bytes
206  pointer allocate(size_type size, const void *ptr = NULLPTR)
207  {
208  CRYPTOPP_UNUSED(ptr); CRYPTOPP_ASSERT(ptr == NULLPTR);
209  this->CheckSize(size);
210  if (size == 0)
211  return NULLPTR;
212 
213 #if CRYPTOPP_BOOL_ALIGN16
214  if (T_Align16)
215  return reinterpret_cast<pointer>(AlignedAllocate(size*sizeof(T)));
216 #endif
217 
218  return reinterpret_cast<pointer>(UnalignedAllocate(size*sizeof(T)));
219  }
220 
221  /// \brief Deallocates a block of memory
222  /// \param ptr the pointer for the allocation
223  /// \param size the size of the allocation, in elements
224  /// \details Internally, SecureWipeArray() is called before deallocating the
225  /// memory. Once the memory block is wiped or zeroized, AlignedDeallocate()
226  /// or UnalignedDeallocate() is called.
227  /// \details AlignedDeallocate() is used if T_Align16 is true.
228  /// UnalignedDeallocate() used if T_Align16 is false.
229  void deallocate(void *ptr, size_type size)
230  {
231  // Avoid assert on pointer in deallocate. SecBlock regularly uses NULL
232  // pointers rather returning non-NULL 0-sized pointers.
233  if (ptr)
234  {
235  SecureWipeArray(reinterpret_cast<pointer>(ptr), size);
236 
237 #if CRYPTOPP_BOOL_ALIGN16
238  if (T_Align16)
239  return AlignedDeallocate(ptr);
240 #endif
241 
242  UnalignedDeallocate(ptr);
243  }
244  }
245 
246  /// \brief Reallocates a block of memory
247  /// \param oldPtr the previous allocation
248  /// \param oldSize the size of the previous allocation
249  /// \param newSize the new, requested size
250  /// \param preserve flag that indicates if the old allocation should be preserved
251  /// \return pointer to the new memory block
252  /// \details Internally, reallocate() calls StandardReallocate().
253  /// \details If preserve is true, then index 0 is used to begin copying the
254  /// old memory block to the new one. If the block grows, then the old array
255  /// is copied in its entirety. If the block shrinks, then only newSize
256  /// elements are copied from the old block to the new one.
257  /// \note oldSize and newSize are the count of elements, and not the
258  /// number of bytes.
259  pointer reallocate(T *oldPtr, size_type oldSize, size_type newSize, bool preserve)
260  {
261  CRYPTOPP_ASSERT((oldPtr && oldSize) || !(oldPtr || oldSize));
262  return StandardReallocate(*this, oldPtr, oldSize, newSize, preserve);
263  }
264 
265  /// \brief Template class member Rebind
266  /// \tparam V bound class or type
267  /// \details Rebind allows a container class to allocate a different type of object
268  /// to store elements. For example, a std::list will allocate std::list_node to
269  /// store elements in the list.
270  /// \details VS.NET STL enforces the policy of "All STL-compliant allocators
271  /// have to provide a template class member called rebind".
272  template <class V> struct rebind { typedef AllocatorWithCleanup<V, T_Align16> other; };
273 #if _MSC_VER >= 1500
275  template <class V, bool A> AllocatorWithCleanup(const AllocatorWithCleanup<V, A> &) {}
276 #endif
277 };
278 
283 #if defined(CRYPTOPP_WORD128_AVAILABLE)
285 #endif
286 #if CRYPTOPP_BOOL_X86
288 #endif
289 
290 /// \brief NULL allocator
291 /// \tparam T class or type
292 /// \details A NullAllocator is useful for fixed-size, stack based allocations
293 /// (i.e., static arrays used by FixedSizeAllocatorWithCleanup).
294 /// \details A NullAllocator always returns 0 for max_size(), and always returns
295 /// NULL for allocation requests. Though the allocator does not allocate at
296 /// runtime, it does perform a secure wipe or zeroization during cleanup.
297 template <class T>
298 class NullAllocator : public AllocatorBase<T>
299 {
300 public:
301  //LCOV_EXCL_START
302  CRYPTOPP_INHERIT_ALLOCATOR_TYPES
303 
304  // TODO: should this return NULL or throw bad_alloc? Non-Windows C++ standard
305  // libraries always throw. And late mode Windows throws. Early model Windows
306  // (circa VC++ 6.0) returned NULL.
307  pointer allocate(size_type n, const void* unused = NULLPTR)
308  {
309  CRYPTOPP_UNUSED(n); CRYPTOPP_UNUSED(unused);
310  CRYPTOPP_ASSERT(false); return NULLPTR;
311  }
312 
313  void deallocate(void *p, size_type n)
314  {
315  CRYPTOPP_UNUSED(p); CRYPTOPP_UNUSED(n);
316  CRYPTOPP_ASSERT(false);
317  }
318 
319  CRYPTOPP_CONSTEXPR size_type max_size() const {return 0;}
320  //LCOV_EXCL_STOP
321 };
322 
323 /// \brief Static secure memory block with cleanup
324 /// \tparam T class or type
325 /// \tparam S fixed-size of the stack-based memory block, in elements
326 /// \tparam T_Align16 boolean that determines whether allocations should
327 /// be aligned on a 16-byte boundary
328 /// \details FixedSizeAllocatorWithCleanup provides a fixed-size, stack-
329 /// based allocation at compile time. The class can grow its memory
330 /// block at runtime if a suitable allocator is available. If size
331 /// grows beyond S and a suitable allocator is available, then the
332 /// statically allocated array is obsoleted.
333 /// \note This allocator can't be used with standard collections because
334 /// they require that all objects of the same allocator type are equivalent.
335 template <class T, size_t S, class A = NullAllocator<T>, bool T_Align16 = false>
337 {
338  // The body of FixedSizeAllocatorWithCleanup is provided in the two
339  // partial specializations that follow. The two specializations
340  // pivot on the boolean template parameter T_Align16. AIX, Solaris,
341  // IBM XLC and SunCC receive a little extra help. We managed to
342  // clear most of the warnings.
343 };
344 
345 /// \brief Static secure memory block with cleanup
346 /// \tparam T class or type
347 /// \tparam S fixed-size of the stack-based memory block, in elements
348 /// \details FixedSizeAllocatorWithCleanup provides a fixed-size, stack-
349 /// based allocation at compile time. The class can grow its memory
350 /// block at runtime if a suitable allocator is available. If size
351 /// grows beyond S and a suitable allocator is available, then the
352 /// statically allocated array is obsoleted.
353 /// \note This allocator can't be used with standard collections because
354 /// they require that all objects of the same allocator type are equivalent.
355 template <class T, size_t S, class A>
356 class FixedSizeAllocatorWithCleanup<T, S, A, true> : public AllocatorBase<T>
357 {
358 public:
359  CRYPTOPP_INHERIT_ALLOCATOR_TYPES
360 
361  /// \brief Constructs a FixedSizeAllocatorWithCleanup
362  FixedSizeAllocatorWithCleanup() : m_allocated(false) {}
363 
364  /// \brief Allocates a block of memory
365  /// \param size the count elements in the memory block
366  /// \details FixedSizeAllocatorWithCleanup provides a fixed-size, stack-based
367  /// allocation at compile time. If size is less than or equal to
368  /// <tt>S</tt>, then a pointer to the static array is returned.
369  /// \details The class can grow its memory block at runtime if a suitable
370  /// allocator is available. If size grows beyond S and a suitable
371  /// allocator is available, then the statically allocated array is
372  /// obsoleted. If a suitable allocator is not available, as with a
373  /// NullAllocator, then the function returns NULL and a runtime error
374  /// eventually occurs.
375  /// \sa reallocate(), SecBlockWithHint
376  pointer allocate(size_type size)
377  {
378  CRYPTOPP_ASSERT(IsAlignedOn(m_array, 8));
379 
380  if (size <= S && !m_allocated)
381  {
382  m_allocated = true;
383  return GetAlignedArray();
384  }
385  else
386  return m_fallbackAllocator.allocate(size);
387  }
388 
389  /// \brief Allocates a block of memory
390  /// \param size the count elements in the memory block
391  /// \param hint an unused hint
392  /// \details FixedSizeAllocatorWithCleanup provides a fixed-size, stack-
393  /// based allocation at compile time. If size is less than or equal to
394  /// S, then a pointer to the static array is returned.
395  /// \details The class can grow its memory block at runtime if a suitable
396  /// allocator is available. If size grows beyond S and a suitable
397  /// allocator is available, then the statically allocated array is
398  /// obsoleted. If a suitable allocator is not available, as with a
399  /// NullAllocator, then the function returns NULL and a runtime error
400  /// eventually occurs.
401  /// \sa reallocate(), SecBlockWithHint
402  pointer allocate(size_type size, const void *hint)
403  {
404  if (size <= S && !m_allocated)
405  {
406  m_allocated = true;
407  return GetAlignedArray();
408  }
409  else
410  return m_fallbackAllocator.allocate(size, hint);
411  }
412 
413  /// \brief Deallocates a block of memory
414  /// \param ptr a pointer to the memory block to deallocate
415  /// \param size the count elements in the memory block
416  /// \details The memory block is wiped or zeroized before deallocation.
417  /// If the statically allocated memory block is active, then no
418  /// additional actions are taken after the wipe.
419  /// \details If a dynamic memory block is active, then the pointer and
420  /// size are passed to the allocator for deallocation.
421  void deallocate(void *ptr, size_type size)
422  {
423  // Avoid assert on pointer in deallocate. SecBlock regularly uses NULL
424  // pointers rather returning non-NULL 0-sized pointers.
425  if (ptr == GetAlignedArray())
426  {
427  // If the m_allocated assert fires then the bit twiddling for
428  // GetAlignedArray() is probably incorrect for the platform.
429  // Be sure to check CRYPTOPP_ALIGN_DATA(8). The platform may
430  // not have a way to declaritively align data to 8.
431  CRYPTOPP_ASSERT(size <= S);
432  CRYPTOPP_ASSERT(m_allocated);
433  m_allocated = false;
434  SecureWipeArray(reinterpret_cast<pointer>(ptr), size);
435  }
436  else
437  {
438  if (ptr)
439  m_fallbackAllocator.deallocate(ptr, size);
440  }
441  }
442 
443  /// \brief Reallocates a block of memory
444  /// \param oldPtr the previous allocation
445  /// \param oldSize the size of the previous allocation
446  /// \param newSize the new, requested size
447  /// \param preserve flag that indicates if the old allocation should
448  /// be preserved
449  /// \return pointer to the new memory block
450  /// \details FixedSizeAllocatorWithCleanup provides a fixed-size, stack-
451  /// based allocation at compile time. If size is less than or equal to
452  /// S, then a pointer to the static array is returned.
453  /// \details The class can grow its memory block at runtime if a suitable
454  /// allocator is available. If size grows beyond S and a suitable
455  /// allocator is available, then the statically allocated array is
456  /// obsoleted. If a suitable allocator is not available, as with a
457  /// NullAllocator, then the function returns NULL and a runtime error
458  /// eventually occurs.
459  /// \note size is the count of elements, and not the number of bytes.
460  /// \sa reallocate(), SecBlockWithHint
461  pointer reallocate(pointer oldPtr, size_type oldSize, size_type newSize, bool preserve)
462  {
463  if (oldPtr == GetAlignedArray() && newSize <= S)
464  {
465  CRYPTOPP_ASSERT(oldSize <= S);
466  if (oldSize > newSize)
467  SecureWipeArray(oldPtr+newSize, oldSize-newSize);
468  return oldPtr;
469  }
470 
471  pointer newPointer = allocate(newSize, NULLPTR);
472  if (preserve && newSize)
473  {
474  const size_type copySize = STDMIN(oldSize, newSize);
475  if (newPointer && oldPtr) // GCC analyzer warning
476  memcpy_s(newPointer, sizeof(T)*newSize, oldPtr, sizeof(T)*copySize);
477  }
478  deallocate(oldPtr, oldSize);
479  return newPointer;
480  }
481 
482  CRYPTOPP_CONSTEXPR size_type max_size() const
483  {
484  return STDMAX(m_fallbackAllocator.max_size(), S);
485  }
486 
487 private:
488 
489 #if CRYPTOPP_BOOL_ALIGN16
490 
491  // There be demons here... We cannot use CRYPTOPP_ALIGN_DATA(16)
492  // because linkers on 32-bit machines and some 64-bit machines
493  // align the stack to 8-bytes or less, and not 16-bytes as
494  // requested. We can only count on a smaller alignment. All
495  // toolchains tested appear to honor CRYPTOPP_ALIGN_DATA(8). Also
496  // see http://stackoverflow.com/a/1468656/608639.
497  //
498  // The 16-byte alignment is achieved by padding the requested
499  // size with extra elements so we have at least 8-bytes of slack
500  // to work with. Then the array pointer is moved to achieve a
501  // 16-byte alignment.
502  //
503  // The additional 8-bytes introduces a small secondary issue.
504  // The secondary issue is, a large T results in 0 = 8/sizeof(T).
505  // The library is OK but users may hit it. So we need to guard
506  // for a large T, and that is what the enum and PAD achieves.
507  T* GetAlignedArray() {
508 
509  // m_array is aligned on 8 byte boundaries due to
510  // CRYPTOPP_ALIGN_DATA(8). If m_array%16 is 0, then the buffer
511  // is 16-byte aligned and nothing needs to be done. if
512  // m_array%16 is 8, then the buffer is not 16-byte aligned and
513  // we need to add 8. 8 has that nice symmetric property.
514  //
515  // If we needed to use CRYPTOPP_ALIGN_DATA(4) due to toolchain
516  // limitations, then the calculation would be slightly more
517  // costly: ptr = m_array + (16 - (m_array % 16)) % 16;
518  CRYPTOPP_ASSERT(IsAlignedOn(m_array, 8));
519  int off = reinterpret_cast<uintptr_t>(m_array) % 16;
520  byte* ptr = reinterpret_cast<byte*>(m_array) + off;
521 
522  // Verify the 16-byte alignment. This is the point
523  // of these extra gyrations.
524  CRYPTOPP_ASSERT(IsAlignedOn(ptr, 16));
525  // Verify the lower bound. This is Issue 982/988.
527  reinterpret_cast<uintptr_t>(ptr) >=
528  reinterpret_cast<uintptr_t>(m_array)
529  );
530  // Verify the upper bound. Allocated array with
531  // pad is large enough.
533  reinterpret_cast<uintptr_t>(ptr+S*sizeof(T)) <=
534  reinterpret_cast<uintptr_t>(m_array+(S+PAD))
535  );
536 
537  // void* to silence Clang warnings
538  return reinterpret_cast<T*>(
539  static_cast<void*>(ptr)
540  );
541  }
542 
543  // PAD is elements, not bytes, and rounded up to ensure no overflow.
544  enum { Q = sizeof(T), PAD = (Q >= 8) ? 1 : (Q >= 4) ? 2 : (Q >= 2) ? 4 : 8 };
545  // enum { Q = sizeof(T), PAD = (Q >= 16) ? 1 : (Q >= 8) ? 2 : (Q >= 4) ? 4 : (Q >= 2) ? 8 : 16 };
546  CRYPTOPP_ALIGN_DATA(8) T m_array[S+PAD];
547 
548 #else
549 
550  // CRYPTOPP_BOOL_ALIGN16 is 0. Use natural alignment of T.
551  T* GetAlignedArray() {return m_array;}
552  T m_array[S];
553 
554 #endif
555 
556  A m_fallbackAllocator;
557  bool m_allocated;
558 };
559 
560 /// \brief Static secure memory block with cleanup
561 /// \tparam T class or type
562 /// \tparam S fixed-size of the stack-based memory block, in elements
563 /// \details FixedSizeAllocatorWithCleanup provides a fixed-size, stack-
564 /// based allocation at compile time. The class can grow its memory
565 /// block at runtime if a suitable allocator is available. If size
566 /// grows beyond S and a suitable allocator is available, then the
567 /// statically allocated array is obsoleted.
568 /// \note This allocator can't be used with standard collections because
569 /// they require that all objects of the same allocator type are equivalent.
570 template <class T, size_t S, class A>
571 class FixedSizeAllocatorWithCleanup<T, S, A, false> : public AllocatorBase<T>
572 {
573 public:
574  CRYPTOPP_INHERIT_ALLOCATOR_TYPES
575 
576  /// \brief Constructs a FixedSizeAllocatorWithCleanup
577  FixedSizeAllocatorWithCleanup() : m_allocated(false) {}
578 
579  /// \brief Allocates a block of memory
580  /// \param size the count elements in the memory block
581  /// \details FixedSizeAllocatorWithCleanup provides a fixed-size, stack-based
582  /// allocation at compile time. If size is less than or equal to
583  /// <tt>S</tt>, then a pointer to the static array is returned.
584  /// \details The class can grow its memory block at runtime if a suitable
585  /// allocator is available. If size grows beyond S and a suitable
586  /// allocator is available, then the statically allocated array is
587  /// obsoleted. If a suitable allocator is not available, as with a
588  /// NullAllocator, then the function returns NULL and a runtime error
589  /// eventually occurs.
590  /// \sa reallocate(), SecBlockWithHint
591  pointer allocate(size_type size)
592  {
593  CRYPTOPP_ASSERT(IsAlignedOn(m_array, 8));
594 
595  if (size <= S && !m_allocated)
596  {
597  m_allocated = true;
598  return GetAlignedArray();
599  }
600  else
601  return m_fallbackAllocator.allocate(size);
602  }
603 
604  /// \brief Allocates a block of memory
605  /// \param size the count elements in the memory block
606  /// \param hint an unused hint
607  /// \details FixedSizeAllocatorWithCleanup provides a fixed-size, stack-
608  /// based allocation at compile time. If size is less than or equal to
609  /// S, then a pointer to the static array is returned.
610  /// \details The class can grow its memory block at runtime if a suitable
611  /// allocator is available. If size grows beyond S and a suitable
612  /// allocator is available, then the statically allocated array is
613  /// obsoleted. If a suitable allocator is not available, as with a
614  /// NullAllocator, then the function returns NULL and a runtime error
615  /// eventually occurs.
616  /// \sa reallocate(), SecBlockWithHint
617  pointer allocate(size_type size, const void *hint)
618  {
619  if (size <= S && !m_allocated)
620  {
621  m_allocated = true;
622  return GetAlignedArray();
623  }
624  else
625  return m_fallbackAllocator.allocate(size, hint);
626  }
627 
628  /// \brief Deallocates a block of memory
629  /// \param ptr a pointer to the memory block to deallocate
630  /// \param size the count elements in the memory block
631  /// \details The memory block is wiped or zeroized before deallocation.
632  /// If the statically allocated memory block is active, then no
633  /// additional actions are taken after the wipe.
634  /// \details If a dynamic memory block is active, then the pointer and
635  /// size are passed to the allocator for deallocation.
636  void deallocate(void *ptr, size_type size)
637  {
638  // Avoid assert on pointer in deallocate. SecBlock regularly uses NULL
639  // pointers rather returning non-NULL 0-sized pointers.
640  if (ptr == GetAlignedArray())
641  {
642  // If the m_allocated assert fires then
643  // something overwrote the flag.
644  CRYPTOPP_ASSERT(size <= S);
645  CRYPTOPP_ASSERT(m_allocated);
646  m_allocated = false;
647  SecureWipeArray((pointer)ptr, size);
648  }
649  else
650  {
651  if (ptr)
652  m_fallbackAllocator.deallocate(ptr, size);
653  m_allocated = false;
654  }
655  }
656 
657  /// \brief Reallocates a block of memory
658  /// \param oldPtr the previous allocation
659  /// \param oldSize the size of the previous allocation
660  /// \param newSize the new, requested size
661  /// \param preserve flag that indicates if the old allocation should
662  /// be preserved
663  /// \return pointer to the new memory block
664  /// \details FixedSizeAllocatorWithCleanup provides a fixed-size, stack-
665  /// based allocation at compile time. If size is less than or equal to
666  /// S, then a pointer to the static array is returned.
667  /// \details The class can grow its memory block at runtime if a suitable
668  /// allocator is available. If size grows beyond S and a suitable
669  /// allocator is available, then the statically allocated array is
670  /// obsoleted. If a suitable allocator is not available, as with a
671  /// NullAllocator, then the function returns NULL and a runtime error
672  /// eventually occurs.
673  /// \note size is the count of elements, and not the number of bytes.
674  /// \sa reallocate(), SecBlockWithHint
675  pointer reallocate(pointer oldPtr, size_type oldSize, size_type newSize, bool preserve)
676  {
677  if (oldPtr == GetAlignedArray() && newSize <= S)
678  {
679  CRYPTOPP_ASSERT(oldSize <= S);
680  if (oldSize > newSize)
681  SecureWipeArray(oldPtr+newSize, oldSize-newSize);
682  return oldPtr;
683  }
684 
685  pointer newPointer = allocate(newSize, NULLPTR);
686  if (preserve && newSize)
687  {
688  const size_type copySize = STDMIN(oldSize, newSize);
689  if (newPointer && oldPtr) // GCC analyzer warning
690  memcpy_s(newPointer, sizeof(T)*newSize, oldPtr, sizeof(T)*copySize);
691  }
692  deallocate(oldPtr, oldSize);
693  return newPointer;
694  }
695 
696  CRYPTOPP_CONSTEXPR size_type max_size() const
697  {
698  return STDMAX(m_fallbackAllocator.max_size(), S);
699  }
700 
701 private:
702 
703  // T_Align16 is false. Use natural alignment of T.
704  T* GetAlignedArray() {return m_array;}
705  T m_array[S];
706 
707  A m_fallbackAllocator;
708  bool m_allocated;
709 };
710 
711 /// \brief Secure memory block with allocator and cleanup
712 /// \tparam T a class or type
713 /// \tparam A AllocatorWithCleanup derived class for allocation and cleanup
714 template <class T, class A = AllocatorWithCleanup<T> >
715 class SecBlock
716 {
717 public:
718  typedef typename A::value_type value_type;
719  typedef typename A::pointer iterator;
720  typedef typename A::const_pointer const_iterator;
721  typedef typename A::size_type size_type;
722 
723  /// \brief Returns the maximum number of elements the block can hold
724  /// \details <tt>ELEMS_MAX</tt> is the maximum number of elements the
725  /// <tt>SecBlock</tt> can hold. The value of <tt>ELEMS_MAX</tt> is
726  /// <tt>SIZE_MAX/sizeof(T)</tt>. <tt>std::numeric_limits</tt> was avoided
727  /// due to lack of <tt>constexpr</tt>-ness in C++03 and below.
728  /// \note In C++03 and below <tt>ELEMS_MAX</tt> is a static data member of type
729  /// <tt>size_type</tt>. In C++11 and above <tt>ELEMS_MAX</tt> is an <tt>enum</tt>
730  /// inheriting from <tt>size_type</tt>. In both cases <tt>ELEMS_MAX</tt> can be
731  /// used before objects are fully constructed, and it does not suffer the
732  /// limitations of class methods like <tt>max_size</tt>.
733  /// \sa <A HREF="http://github.com/weidai11/cryptopp/issues/346">Issue 346/CVE-2016-9939</A>
734  /// \since Crypto++ 6.0
735 #if defined(CRYPTOPP_DOXYGEN_PROCESSING)
736  static const size_type ELEMS_MAX = ...;
737 #elif defined(_MSC_VER) && (_MSC_VER <= 1400)
738  static const size_type ELEMS_MAX = (~(size_type)0)/sizeof(T);
739 #elif defined(CRYPTOPP_CXX11_STRONG_ENUM)
740  enum : size_type {ELEMS_MAX = A::ELEMS_MAX};
741 #else
742  static const size_type ELEMS_MAX = SIZE_MAX/sizeof(T);
743 #endif
744 
745  /// \brief Construct a SecBlock with space for size elements.
746  /// \param size the size of the allocation, in elements
747  /// \throw std::bad_alloc
748  /// \details The elements are not initialized.
749  /// \note size is the count of elements, and not the number of bytes
750  explicit SecBlock(size_type size=0)
751  : m_mark(ELEMS_MAX), m_size(size), m_ptr(m_alloc.allocate(size, NULLPTR)) { }
752 
753  /// \brief Copy construct a SecBlock from another SecBlock
754  /// \param t the other SecBlock
755  /// \throw std::bad_alloc
757  : m_mark(t.m_mark), m_size(t.m_size), m_ptr(m_alloc.allocate(t.m_size, NULLPTR)) {
758  CRYPTOPP_ASSERT((!t.m_ptr && !m_size) || (t.m_ptr && m_size));
759  if (m_ptr && t.m_ptr)
760  memcpy_s(m_ptr, m_size*sizeof(T), t.m_ptr, t.m_size*sizeof(T));
761  }
762 
763  /// \brief Construct a SecBlock from an array of elements.
764  /// \param ptr a pointer to an array of T
765  /// \param len the number of elements in the memory block
766  /// \throw std::bad_alloc
767  /// \details If <tt>ptr!=NULL</tt> and <tt>len!=0</tt>, then the block is initialized from the pointer
768  /// <tt>ptr</tt>. If <tt>ptr==NULL</tt> and <tt>len!=0</tt>, then the block is initialized to 0.
769  /// Otherwise, the block is empty and not initialized.
770  /// \note size is the count of elements, and not the number of bytes
771  SecBlock(const T *ptr, size_type len)
772  : m_mark(ELEMS_MAX), m_size(len), m_ptr(m_alloc.allocate(len, NULLPTR)) {
773  CRYPTOPP_ASSERT((!m_ptr && !m_size) || (m_ptr && m_size));
774  if (m_ptr && ptr)
775  memcpy_s(m_ptr, m_size*sizeof(T), ptr, len*sizeof(T));
776  else if (m_ptr && m_size)
777  memset(m_ptr, 0, m_size*sizeof(T));
778  }
779 
780  ~SecBlock()
781  {m_alloc.deallocate(m_ptr, STDMIN(m_size, m_mark));}
782 
783 #ifdef __BORLANDC__
784  /// \brief Cast operator
785  /// \return block pointer cast to non-const <tt>T *</tt>
786  operator T *() const
787  {return (T*)m_ptr;}
788 #else
789  /// \brief Cast operator
790  /// \return block pointer cast to <tt>const void *</tt>
791  operator const void *() const
792  {return m_ptr;}
793 
794  /// \brief Cast operator
795  /// \return block pointer cast to non-const <tt>void *</tt>
796  operator void *()
797  {return m_ptr;}
798 
799  /// \brief Cast operator
800  /// \return block pointer cast to <tt>const T *</tt>
801  operator const T *() const
802  {return m_ptr;}
803 
804  /// \brief Cast operator
805  /// \return block pointer cast to non-const <tt>T *</tt>
806  operator T *()
807  {return m_ptr;}
808 #endif
809 
810  /// \brief Provides an iterator pointing to the first element in the memory block
811  /// \return iterator pointing to the first element in the memory block
812  iterator begin()
813  {return m_ptr;}
814  /// \brief Provides a constant iterator pointing to the first element in the memory block
815  /// \return constant iterator pointing to the first element in the memory block
816  const_iterator begin() const
817  {return m_ptr;}
818  /// \brief Provides an iterator pointing beyond the last element in the memory block
819  /// \return iterator pointing beyond the last element in the memory block
820  iterator end()
821  {return m_ptr+m_size;}
822  /// \brief Provides a constant iterator pointing beyond the last element in the memory block
823  /// \return constant iterator pointing beyond the last element in the memory block
824  const_iterator end() const
825  {return m_ptr+m_size;}
826 
827  /// \brief Provides a pointer to the first element in the memory block
828  /// \return pointer to the first element in the memory block
829  typename A::pointer data() {return m_ptr;}
830  /// \brief Provides a pointer to the first element in the memory block
831  /// \return constant pointer to the first element in the memory block
832  typename A::const_pointer data() const {return m_ptr;}
833 
834  /// \brief Provides the count of elements in the SecBlock
835  /// \return number of elements in the memory block
836  /// \note the return value is the count of elements, and not the number of bytes
837  size_type size() const {return m_size;}
838  /// \brief Determines if the SecBlock is empty
839  /// \return true if number of elements in the memory block is 0, false otherwise
840  bool empty() const {return m_size == 0;}
841 
842  /// \brief Provides a byte pointer to the first element in the memory block
843  /// \return byte pointer to the first element in the memory block
844  byte * BytePtr() {return (byte *)m_ptr;}
845  /// \brief Return a byte pointer to the first element in the memory block
846  /// \return constant byte pointer to the first element in the memory block
847  const byte * BytePtr() const {return (const byte *)m_ptr;}
848  /// \brief Provides the number of bytes in the SecBlock
849  /// \return the number of bytes in the memory block
850  /// \note the return value is the number of bytes, and not count of elements.
851  size_type SizeInBytes() const {return m_size*sizeof(T);}
852 
853  /// \brief Sets the number of elements to zeroize
854  /// \param count the number of elements
855  /// \details SetMark is a remediation for Issue 346/CVE-2016-9939 while
856  /// preserving the streaming interface. The <tt>count</tt> controls the number of
857  /// elements zeroized, which can be less than <tt>size</tt> or 0.
858  /// \details An internal variable, <tt>m_mark</tt>, is initialized to the maximum number
859  /// of elements. The maximum number of elements is <tt>ELEMS_MAX</tt>. Deallocation
860  /// triggers a zeroization, and the number of elements zeroized is
861  /// <tt>STDMIN(m_size, m_mark)</tt>. After zeroization, the memory is returned to the
862  /// system.
863  /// \details The ASN.1 decoder uses SetMark() to set the element count to 0
864  /// before throwing an exception. In this case, the attacker provides a large
865  /// BER encoded length (say 64MB) but only a small number of content octets
866  /// (say 16). If the allocator zeroized all 64MB, then a transient DoS could
867  /// occur as CPU cycles are spent zeroizing unintialized memory.
868  /// \details Generally speaking, any operation which changes the size of the SecBlock
869  /// results in the mark being reset to <tt>ELEMS_MAX</tt>. In particular, if Assign(),
870  /// New(), Grow(), CleanNew(), CleanGrow() are called, then the count is reset to
871  /// <tt>ELEMS_MAX</tt>. The list is not exhaustive.
872  /// \since Crypto++ 6.0
873  /// \sa <A HREF="http://github.com/weidai11/cryptopp/issues/346">Issue 346/CVE-2016-9939</A>
874  void SetMark(size_t count) {m_mark = count;}
875 
876  /// \brief Set contents and size from an array
877  /// \param ptr a pointer to an array of T
878  /// \param len the number of elements in the memory block
879  /// \details If the memory block is reduced in size, then the reclaimed memory is set to 0.
880  /// Assign() resets the element count after the previous block is zeroized.
881  void Assign(const T *ptr, size_type len)
882  {
883  New(len);
884  if (m_ptr && ptr) // GCC analyzer warning
885  memcpy_s(m_ptr, m_size*sizeof(T), ptr, len*sizeof(T));
886  m_mark = ELEMS_MAX;
887  }
888 
889  /// \brief Set contents from a value
890  /// \param count the number of values to copy
891  /// \param value the value, repeated count times
892  /// \details If the memory block is reduced in size, then the reclaimed memory is set to 0.
893  /// Assign() resets the element count after the previous block is zeroized.
894  void Assign(size_type count, T value)
895  {
896  New(count);
897  for (size_t i=0; i<count; ++i)
898  m_ptr[i] = value;
899 
900  m_mark = ELEMS_MAX;
901  }
902 
903  /// \brief Copy contents from another SecBlock
904  /// \param t the other SecBlock
905  /// \details Assign checks for self assignment.
906  /// \details If the memory block is reduced in size, then the reclaimed memory is set to 0.
907  /// If an assignment occurs, then Assign() resets the element count after the previous block
908  /// is zeroized.
909  void Assign(const SecBlock<T, A> &t)
910  {
911  if (this != &t)
912  {
913  New(t.m_size);
914  if (m_ptr && t.m_ptr) // GCC analyzer warning
915  memcpy_s(m_ptr, m_size*sizeof(T), t, t.m_size*sizeof(T));
916  }
917  m_mark = ELEMS_MAX;
918  }
919 
920  /// \brief Assign contents from another SecBlock
921  /// \param t the other SecBlock
922  /// \details Internally, operator=() calls Assign().
923  /// \details If the memory block is reduced in size, then the reclaimed memory is set to 0.
924  /// If an assignment occurs, then Assign() resets the element count after the previous block
925  /// is zeroized.
927  {
928  // Assign guards for self-assignment
929  Assign(t);
930  return *this;
931  }
932 
933  /// \brief Append contents from another SecBlock
934  /// \param t the other SecBlock
935  /// \details Internally, this SecBlock calls Grow and then appends t.
937  {
938  CRYPTOPP_ASSERT((!t.m_ptr && !t.m_size) || (t.m_ptr && t.m_size));
939  if (t.m_size)
940  {
941  const size_type oldSize = m_size;
942  if (this != &t) // s += t
943  {
944  Grow(m_size+t.m_size);
945  if (m_ptr && t.m_ptr) // GCC analyzer warning
946  memcpy_s(m_ptr+oldSize, (m_size-oldSize)*sizeof(T), t.m_ptr, t.m_size*sizeof(T));
947  }
948  else // t += t
949  {
950  Grow(m_size*2);
951  if (m_ptr && t.m_ptr) // GCC analyzer warning
952  memcpy_s(m_ptr+oldSize, (m_size-oldSize)*sizeof(T), m_ptr, oldSize*sizeof(T));
953  }
954  }
955  m_mark = ELEMS_MAX;
956  return *this;
957  }
958 
959  /// \brief Construct a SecBlock from this and another SecBlock
960  /// \param t the other SecBlock
961  /// \return a newly constructed SecBlock that is a conacentation of this and t
962  /// \details Internally, a new SecBlock is created from this and a concatenation of t.
964  {
965  CRYPTOPP_ASSERT((!m_ptr && !m_size) || (m_ptr && m_size));
966  CRYPTOPP_ASSERT((!t.m_ptr && !t.m_size) || (t.m_ptr && t.m_size));
967  if(!t.m_size) return SecBlock(*this);
968 
969  SecBlock<T, A> result(m_size+t.m_size);
970  if (m_size)
971  memcpy_s(result.m_ptr, result.m_size*sizeof(T), m_ptr, m_size*sizeof(T));
972  if (result.m_ptr && t.m_ptr) // GCC analyzer warning
973  memcpy_s(result.m_ptr+m_size, (result.m_size-m_size)*sizeof(T), t.m_ptr, t.m_size*sizeof(T));
974  return result;
975  }
976 
977  /// \brief Bitwise compare two SecBlocks
978  /// \param t the other SecBlock
979  /// \return true if the size and bits are equal, false otherwise
980  /// \details Uses a constant time compare if the arrays are equal size. The constant time
981  /// compare is VerifyBufsEqual() found in misc.h.
982  /// \sa operator!=()
983  bool operator==(const SecBlock<T, A> &t) const
984  {
985  return m_size == t.m_size && VerifyBufsEqual(
986  reinterpret_cast<const byte*>(m_ptr),
987  reinterpret_cast<const byte*>(t.m_ptr), m_size*sizeof(T));
988  }
989 
990  /// \brief Bitwise compare two SecBlocks
991  /// \param t the other SecBlock
992  /// \return true if the size and bits are equal, false otherwise
993  /// \details Uses a constant time compare if the arrays are equal size. The constant time
994  /// compare is VerifyBufsEqual() found in misc.h.
995  /// \details Internally, operator!=() returns the inverse of operator==().
996  /// \sa operator==()
997  bool operator!=(const SecBlock<T, A> &t) const
998  {
999  return !operator==(t);
1000  }
1001 
1002  /// \brief Change size without preserving contents
1003  /// \param newSize the new size of the memory block
1004  /// \details Old content is not preserved. If the memory block is reduced in size,
1005  /// then the reclaimed memory is set to 0. If the memory block grows in size, then
1006  /// the new memory is not initialized. New() resets the element count after the
1007  /// previous block is zeroized.
1008  /// \details Internally, this SecBlock calls reallocate().
1009  /// \sa New(), CleanNew(), Grow(), CleanGrow(), resize()
1010  void New(size_type newSize)
1011  {
1012  m_ptr = m_alloc.reallocate(m_ptr, m_size, newSize, false);
1013  m_size = newSize;
1014  m_mark = ELEMS_MAX;
1015  }
1016 
1017  /// \brief Change size without preserving contents
1018  /// \param newSize the new size of the memory block
1019  /// \details Old content is not preserved. If the memory block is reduced in size,
1020  /// then the reclaimed content is set to 0. If the memory block grows in size, then
1021  /// the new memory is initialized to 0. CleanNew() resets the element count after the
1022  /// previous block is zeroized.
1023  /// \details Internally, this SecBlock calls New().
1024  /// \sa New(), CleanNew(), Grow(), CleanGrow(), resize()
1025  void CleanNew(size_type newSize)
1026  {
1027  New(newSize);
1028  if (m_ptr) {memset_z(m_ptr, 0, m_size*sizeof(T));}
1029  m_mark = ELEMS_MAX;
1030  }
1031 
1032  /// \brief Change size and preserve contents
1033  /// \param newSize the new size of the memory block
1034  /// \details Old content is preserved. New content is not initialized.
1035  /// \details Internally, this SecBlock calls reallocate() when size must increase. If the
1036  /// size does not increase, then Grow() does not take action. If the size must
1037  /// change, then use resize(). Grow() resets the element count after the
1038  /// previous block is zeroized.
1039  /// \sa New(), CleanNew(), Grow(), CleanGrow(), resize()
1040  void Grow(size_type newSize)
1041  {
1042  if (newSize > m_size)
1043  {
1044  m_ptr = m_alloc.reallocate(m_ptr, m_size, newSize, true);
1045  m_size = newSize;
1046  }
1047  m_mark = ELEMS_MAX;
1048  }
1049 
1050  /// \brief Change size and preserve contents
1051  /// \param newSize the new size of the memory block
1052  /// \details Old content is preserved. New content is initialized to 0.
1053  /// \details Internally, this SecBlock calls reallocate() when size must increase. If the
1054  /// size does not increase, then CleanGrow() does not take action. If the size must
1055  /// change, then use resize(). CleanGrow() resets the element count after the
1056  /// previous block is zeroized.
1057  /// \sa New(), CleanNew(), Grow(), CleanGrow(), resize()
1058  void CleanGrow(size_type newSize)
1059  {
1060  if (newSize > m_size)
1061  {
1062  m_ptr = m_alloc.reallocate(m_ptr, m_size, newSize, true);
1063  memset_z(m_ptr+m_size, 0, (newSize-m_size)*sizeof(T));
1064  m_size = newSize;
1065  }
1066  m_mark = ELEMS_MAX;
1067  }
1068 
1069  /// \brief Change size and preserve contents
1070  /// \param newSize the new size of the memory block
1071  /// \details Old content is preserved. If the memory block grows in size, then
1072  /// new memory is not initialized. resize() resets the element count after
1073  /// the previous block is zeroized.
1074  /// \details Internally, this SecBlock calls reallocate().
1075  /// \sa New(), CleanNew(), Grow(), CleanGrow(), resize()
1076  void resize(size_type newSize)
1077  {
1078  m_ptr = m_alloc.reallocate(m_ptr, m_size, newSize, true);
1079  m_size = newSize;
1080  m_mark = ELEMS_MAX;
1081  }
1082 
1083  /// \brief Swap contents with another SecBlock
1084  /// \param b the other SecBlock
1085  /// \details Internally, std::swap() is called on m_alloc, m_size and m_ptr.
1087  {
1088  // Swap must occur on the allocator in case its FixedSize that spilled into the heap.
1089  std::swap(m_alloc, b.m_alloc);
1090  std::swap(m_mark, b.m_mark);
1091  std::swap(m_size, b.m_size);
1092  std::swap(m_ptr, b.m_ptr);
1093  }
1094 
1095 protected:
1096  A m_alloc;
1097  size_type m_mark, m_size;
1098  T *m_ptr;
1099 };
1100 
1101 #ifdef CRYPTOPP_DOXYGEN_PROCESSING
1102 /// \brief \ref SecBlock "SecBlock<byte>" typedef.
1103 class SecByteBlock : public SecBlock<byte> {};
1104 /// \brief \ref SecBlock "SecBlock<word>" typedef.
1105 class SecWordBlock : public SecBlock<word> {};
1106 /// \brief SecBlock using \ref AllocatorWithCleanup "AllocatorWithCleanup<byte, true>" typedef
1107 class AlignedSecByteBlock : public SecBlock<byte, AllocatorWithCleanup<byte, true> > {};
1108 #else
1112 #endif
1113 
1114 // No need for move semantics on derived class *if* the class does not add any
1115 // data members; see http://stackoverflow.com/q/31755703, and Rule of {0|3|5}.
1116 
1117 /// \brief Fixed size stack-based SecBlock
1118 /// \tparam T class or type
1119 /// \tparam S fixed-size of the stack-based memory block, in elements
1120 /// \tparam A AllocatorBase derived class for allocation and cleanup
1121 template <class T, unsigned int S, class A = FixedSizeAllocatorWithCleanup<T, S> >
1122 class FixedSizeSecBlock : public SecBlock<T, A>
1123 {
1124 public:
1125  /// \brief Construct a FixedSizeSecBlock
1126  explicit FixedSizeSecBlock() : SecBlock<T, A>(S) {}
1127 };
1128 
1129 /// \brief Fixed size stack-based SecBlock with 16-byte alignment
1130 /// \tparam T class or type
1131 /// \tparam S fixed-size of the stack-based memory block, in elements
1132 /// \tparam T_Align16 boolean that determines whether allocations should be aligned on a 16-byte boundary
1133 template <class T, unsigned int S, bool T_Align16 = true>
1134 class FixedSizeAlignedSecBlock : public FixedSizeSecBlock<T, S, FixedSizeAllocatorWithCleanup<T, S, NullAllocator<T>, T_Align16> >
1135 {
1136 };
1137 
1138 /// \brief Stack-based SecBlock that grows into the heap
1139 /// \tparam T class or type
1140 /// \tparam S fixed-size of the stack-based memory block, in elements
1141 /// \tparam A AllocatorBase derived class for allocation and cleanup
1142 template <class T, unsigned int S, class A = FixedSizeAllocatorWithCleanup<T, S, AllocatorWithCleanup<T> > >
1143 class SecBlockWithHint : public SecBlock<T, A>
1144 {
1145 public:
1146  /// construct a SecBlockWithHint with a count of elements
1147  explicit SecBlockWithHint(size_t size) : SecBlock<T, A>(size) {}
1148 };
1149 
1150 template<class T, bool A, class V, bool B>
1151 inline bool operator==(const CryptoPP::AllocatorWithCleanup<T, A>&, const CryptoPP::AllocatorWithCleanup<V, B>&) {return (true);}
1152 template<class T, bool A, class V, bool B>
1153 inline bool operator!=(const CryptoPP::AllocatorWithCleanup<T, A>&, const CryptoPP::AllocatorWithCleanup<V, B>&) {return (false);}
1154 
1155 NAMESPACE_END
1156 
1157 NAMESPACE_BEGIN(std)
1158 
1159 /// \brief Swap two SecBlocks
1160 /// \tparam T class or type
1161 /// \tparam A AllocatorBase derived class for allocation and cleanup
1162 /// \param a the first SecBlock
1163 /// \param b the second SecBlock
1164 template <class T, class A>
1165 inline void swap(CryptoPP::SecBlock<T, A> &a, CryptoPP::SecBlock<T, A> &b)
1166 {
1167  a.swap(b);
1168 }
1169 
1170 #if defined(_STLP_DONT_SUPPORT_REBIND_MEMBER_TEMPLATE) || (defined(_STLPORT_VERSION) && !defined(_STLP_MEMBER_TEMPLATE_CLASSES))
1171 // working for STLport 5.1.3 and MSVC 6 SP5
1172 template <class _Tp1, class _Tp2>
1173 inline CryptoPP::AllocatorWithCleanup<_Tp2>&
1174 __stl_alloc_rebind(CryptoPP::AllocatorWithCleanup<_Tp1>& __a, const _Tp2*)
1175 {
1176  return (CryptoPP::AllocatorWithCleanup<_Tp2>&)(__a);
1177 }
1178 #endif
1179 
1180 NAMESPACE_END
1181 
1182 #if CRYPTOPP_MSC_VERSION
1183 # pragma warning(pop)
1184 #endif
1185 
1186 #endif
CRYPTOPP_DLL void UnalignedDeallocate(void *ptr)
Frees a buffer allocated with UnalignedAllocate.
iterator end()
Provides an iterator pointing beyond the last element in the memory block.
Definition: secblock.h:820
An invalid argument was detected.
Definition: cryptlib.h:202
void construct(V *ptr, Args &&... args)
Constructs a new V using variadic arguments.
Definition: secblock.h:91
Base class for all allocators used by SecBlock.
Definition: secblock.h:29
void swap(SecBlock< T, A > &b)
Swap contents with another SecBlock.
Definition: secblock.h:1086
Stack-based SecBlock that grows into the heap.
Definition: secblock.h:1143
Utility functions for the Crypto++ library.
FixedSizeSecBlock()
Construct a FixedSizeSecBlock.
Definition: secblock.h:1126
void CleanNew(size_type newSize)
Change size without preserving contents.
Definition: secblock.h:1025
SecBlock< T, A > & operator=(const SecBlock< T, A > &t)
Assign contents from another SecBlock.
Definition: secblock.h:926
size_type SizeInBytes() const
Provides the number of bytes in the SecBlock.
Definition: secblock.h:851
void resize(size_type newSize)
Change size and preserve contents.
Definition: secblock.h:1076
SecBlock< T, A > & operator+=(const SecBlock< T, A > &t)
Append contents from another SecBlock.
Definition: secblock.h:936
static const size_type ELEMS_MAX
Returns the maximum number of elements the allocator can provide.
Definition: secblock.h:58
CRYPTOPP_DLL void * AlignedAllocate(size_t size)
Allocates a buffer on 16-byte boundary.
void CleanGrow(size_type newSize)
Change size and preserve contents.
Definition: secblock.h:1058
const_iterator end() const
Provides a constant iterator pointing beyond the last element in the memory block.
Definition: secblock.h:824
void Assign(const SecBlock< T, A > &t)
Copy contents from another SecBlock.
Definition: secblock.h:909
SecBlock< T, A > operator+(const SecBlock< T, A > &t)
Construct a SecBlock from this and another SecBlock.
Definition: secblock.h:963
pointer allocate(size_type size, const void *hint)
Allocates a block of memory.
Definition: secblock.h:617
SecBlock(size_type size=0)
Construct a SecBlock with space for size elements.
Definition: secblock.h:750
Secure memory block with allocator and cleanup.
Definition: secblock.h:715
void memcpy_s(void *dest, size_t sizeInBytes, const void *src, size_t count)
Bounds checking replacement for memcpy()
Definition: misc.h:506
Library configuration file.
bool operator!=(const SecBlock< T, A > &t) const
Bitwise compare two SecBlocks.
Definition: secblock.h:997
STL namespace.
Common C++ header files.
void New(size_type newSize)
Change size without preserving contents.
Definition: secblock.h:1010
SecBlock<byte> typedef.
Definition: secblock.h:1103
pointer allocate(size_type size, const void *hint)
Allocates a block of memory.
Definition: secblock.h:402
pointer reallocate(T *oldPtr, size_type oldSize, size_type newSize, bool preserve)
Reallocates a block of memory.
Definition: secblock.h:259
pointer reallocate(pointer oldPtr, size_type oldSize, size_type newSize, bool preserve)
Reallocates a block of memory.
Definition: secblock.h:461
bool operator==(const OID &lhs, const OID &rhs)
Compare two OIDs for equality.
Static secure memory block with cleanup.
Definition: secblock.h:336
Allocates a block of memory with cleanup.
Definition: secblock.h:187
size_type max_size() const
Returns the maximum number of elements the allocator can provide.
Definition: secblock.h:73
Functions for allocating aligned buffers.
pointer allocate(size_type size)
Allocates a block of memory.
Definition: secblock.h:591
bool operator!=(const OID &lhs, const OID &rhs)
Compare two OIDs for inequality.
void SecureWipeArray(T *buf, size_t n)
Sets each element of an array to 0.
Definition: misc.h:1470
bool IsAlignedOn(const void *ptr, unsigned int alignment)
Determines whether ptr is aligned to a minimum value.
Definition: misc.h:1206
pointer allocate(size_type size)
Allocates a block of memory.
Definition: secblock.h:376
CRYPTOPP_DLL void * UnalignedAllocate(size_t size)
Allocates a buffer.
void * memset_z(void *ptr, int val, size_t num)
Memory block initializer.
Definition: misc.h:618
Template class member Rebind.
Definition: secblock.h:272
A::pointer data()
Provides a pointer to the first element in the memory block.
Definition: secblock.h:829
void Assign(const T *ptr, size_type len)
Set contents and size from an array.
Definition: secblock.h:881
FixedSizeAllocatorWithCleanup()
Constructs a FixedSizeAllocatorWithCleanup.
Definition: secblock.h:362
A::const_pointer data() const
Provides a pointer to the first element in the memory block.
Definition: secblock.h:832
#define CRYPTOPP_DLL_TEMPLATE_CLASS
Instantiate templates in a dynamic library.
Definition: config_dll.h:72
Fixed size stack-based SecBlock with 16-byte alignment.
Definition: secblock.h:1134
void deallocate(void *ptr, size_type size)
Deallocates a block of memory.
Definition: secblock.h:421
pointer reallocate(pointer oldPtr, size_type oldSize, size_type newSize, bool preserve)
Reallocates a block of memory.
Definition: secblock.h:675
FixedSizeAllocatorWithCleanup()
Constructs a FixedSizeAllocatorWithCleanup.
Definition: secblock.h:577
SecBlock using AllocatorWithCleanup<byte, true> typedef.
Definition: secblock.h:1107
pointer allocate(size_type size, const void *ptr=NULL)
Allocates a block of memory.
Definition: secblock.h:206
Fixed size stack-based SecBlock.
Definition: secblock.h:1122
SecBlock(const SecBlock< T, A > &t)
Copy construct a SecBlock from another SecBlock.
Definition: secblock.h:756
const T & STDMIN(const T &a, const T &b)
Replacement function for std::min.
Definition: misc.h:635
#define CRYPTOPP_ASSERT(exp)
Debugging and diagnostic assertion.
Definition: trap.h:68
void deallocate(void *ptr, size_type size)
Deallocates a block of memory.
Definition: secblock.h:229
iterator begin()
Provides an iterator pointing to the first element in the memory block.
Definition: secblock.h:812
bool operator==(const SecBlock< T, A > &t) const
Bitwise compare two SecBlocks.
Definition: secblock.h:983
NULL allocator.
Definition: secblock.h:298
unsigned char byte
8-bit unsigned datatype
Definition: config_int.h:56
SecBlockWithHint(size_t size)
construct a SecBlockWithHint with a count of elements
Definition: secblock.h:1147
const byte * BytePtr() const
Return a byte pointer to the first element in the memory block.
Definition: secblock.h:847
A::pointer StandardReallocate(A &alloc, T *oldPtr, typename A::size_type oldSize, typename A::size_type newSize, bool preserve)
Reallocation function.
Definition: secblock.h:149
CRYPTOPP_DLL void AlignedDeallocate(void *ptr)
Frees a buffer allocated with AlignedAllocate.
const_iterator begin() const
Provides a constant iterator pointing to the first element in the memory block.
Definition: secblock.h:816
SecBlock(const T *ptr, size_type len)
Construct a SecBlock from an array of elements.
Definition: secblock.h:771
const T & STDMAX(const T &a, const T &b)
Replacement function for std::max.
Definition: misc.h:646
void deallocate(void *ptr, size_type size)
Deallocates a block of memory.
Definition: secblock.h:636
void Grow(size_type newSize)
Change size and preserve contents.
Definition: secblock.h:1040
CRYPTOPP_DLL bool VerifyBufsEqual(const byte *buf1, const byte *buf2, size_t count)
Performs a near constant-time comparison of two equally sized buffers.
Crypto++ library namespace.
void destroy(V *ptr)
Destroys an V constructed with variadic arguments.
Definition: secblock.h:98
void Assign(size_type count, T value)
Set contents from a value.
Definition: secblock.h:894
void SetMark(size_t count)
Sets the number of elements to zeroize.
Definition: secblock.h:874
void swap(::SecBlock< T, A > &a, ::SecBlock< T, A > &b)
Swap two SecBlocks.
Definition: secblock.h:1165
bool empty() const
Determines if the SecBlock is empty.
Definition: secblock.h:840
SecBlock<word> typedef.
Definition: secblock.h:1105
size_type size() const
Provides the count of elements in the SecBlock.
Definition: secblock.h:837
#define SIZE_MAX
The maximum value of a machine word.
Definition: misc.h:116
byte * BytePtr()
Provides a byte pointer to the first element in the memory block.
Definition: secblock.h:844