Crypto++  8.6
Free C++ class library of cryptographic schemes
padlkrng.cpp
1 // via-rng.cpp - written and placed in public domain by Jeffrey Walton and Uri Blumenthal.
2 
3 #include "pch.h"
4 #include "config.h"
5 #include "cryptlib.h"
6 #include "secblock.h"
7 #include "padlkrng.h"
8 #include "cpu.h"
9 
10 // The Padlock Security Engine RNG has a few items to be aware of. You can
11 // find copies of the Programmer's manual, Cryptography Research Inc audit
12 // report, and other goodies at http://www.cryptopp.com/wiki/VIA_Padlock.
13 
14 #if CRYPTOPP_MSC_VERSION
15 # pragma warning(disable: 4702)
16 #endif
17 
18 NAMESPACE_BEGIN(CryptoPP)
19 
20 std::string PadlockRNG::AlgorithmProvider() const
21 {
22  return "Padlock";
23 }
24 
26  : m_divisor(DivisorHelper(divisor)), m_msr(0)
27 {
28 #if defined(CRYPTOPP_X86_ASM_AVAILABLE)
29  if (!HasPadlockRNG())
30 #endif
31  throw PadlockRNG_Err("PadlockRNG", "PadlockRNG generator not available");
32 }
33 
34 void PadlockRNG::GenerateBlock(byte *output, size_t size)
35 {
36  CRYPTOPP_UNUSED(output); CRYPTOPP_UNUSED(size);
37 #if defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(__GNUC__)
38  while (size)
39  {
40  __asm__ __volatile__
41  (
43  "mov %1, %%rdi ;\n"
44  "movl %2, %%edx ;\n"
45 #else
46  "mov %1, %%edi ;\n"
47  "movl %2, %%edx ;\n"
48 #endif
49 
50  // xstore-rng
51  ".byte 0x0f, 0xa7, 0xc0 ;\n"
52  "movl %%eax, %0 ;\n"
53 
54  : "=g" (m_msr) : "g" (m_buffer.data()), "g" (m_divisor)
56  : "rax", "rdx", "rdi", "cc"
57 #else
58  : "eax", "edx", "edi", "cc"
59 #endif
60  );
61 
62  const size_t ret = m_msr & 0x1f;
63  const size_t rem = STDMIN<size_t>(ret, STDMIN<size_t>(size, 16U /*buffer size*/));
64  std::memcpy(output, m_buffer, rem);
65  size -= rem; output += rem;
66  }
67 #elif defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(_MSC_VER) && defined(_M_IX86)
68  while (size)
69  {
70  word32 result, divisor = m_divisor;
71  byte *buffer = reinterpret_cast<byte*>(m_buffer.data());
72  __asm {
73  mov edi, buffer
74  mov edx, divisor
75  _emit 0x0f
76  _emit 0xa7
77  _emit 0xc0
78  mov result, eax
79  }
80 
81  const size_t ret = (m_msr = result) & 0x1f;
82  const size_t rem = STDMIN<size_t>(ret, STDMIN<size_t>(size, 16U /*buffer size*/));
83  std::memcpy(output, buffer, rem);
84  size -= rem; output += rem;
85  }
86 #else
87  throw PadlockRNG_Err("GenerateBlock", "PadlockRNG generator not available");
88 #endif // CRYPTOPP_X86_ASM_AVAILABLE
89 }
90 
92 {
94  n = RoundUpToMultipleOf(n, sizeof(word32));
95 
96  size_t count = STDMIN(n, discard.SizeInBytes());
97  while (count)
98  {
99  GenerateBlock(discard.BytePtr(), count);
100  n -= count;
101  count = STDMIN(n, discard.SizeInBytes());
102  }
103 }
104 
105 NAMESPACE_END
RoundUpToMultipleOf
T1 RoundUpToMultipleOf(const T1 &n, const T2 &m)
Rounds a value up to a multiple of a second value.
Definition: misc.h:1174
secblock.h
Classes and functions for secure memory allocations.
PadlockRNG::PadlockRNG
PadlockRNG(word32 divisor=1)
Construct a PadlockRNG generator.
Definition: padlkrng.cpp:25
pch.h
Precompiled header file.
SecBlock::BytePtr
byte * BytePtr()
Provides a byte pointer to the first element in the memory block.
Definition: secblock.h:876
word32
unsigned int word32
32-bit unsigned datatype
Definition: config_int.h:62
SecBlock::SizeInBytes
size_type SizeInBytes() const
Provides the number of bytes in the SecBlock.
Definition: secblock.h:885
CRYPTOPP_BOOL_X64
#define CRYPTOPP_BOOL_X64
32-bit x86 platform
Definition: config_cpu.h:48
STDMIN
const T & STDMIN(const T &a, const T &b)
Replacement function for std::min.
Definition: misc.h:655
cpu.h
Functions for CPU features and intrinsics.
FixedSizeSecBlock< word32, 4 >
padlkrng.h
Classes for VIA Padlock RNG.
CRYPTOPP_BOOL_X32
#define CRYPTOPP_BOOL_X32
32-bit x32 platform
Definition: config_cpu.h:44
PadlockRNG
Hardware generated random numbers using VIA XSTORE.
Definition: padlkrng.h:50
CryptoPP
Crypto++ library namespace.
config.h
Library configuration file.
PadlockRNG::DiscardBytes
virtual void DiscardBytes(size_t n)
Generate and discard n bytes.
Definition: padlkrng.cpp:91
SecBlock::data
A::pointer data()
Provides a pointer to the first element in the memory block.
Definition: secblock.h:857
cryptlib.h
Abstract base classes that provide a uniform interface to this library.
PadlockRNG::GenerateBlock
virtual void GenerateBlock(byte *output, size_t size)
Generate random array of bytes.
Definition: padlkrng.cpp:34
PadlockRNG_Err
Exception thrown when a PadlockRNG generator encounters a generator related error.
Definition: padlkrng.h:20