Crypto++ 8.9 Free C++ class library of cryptographic schemes

osrng.cpp
1 // osrng.cpp - originally written and placed in the public domain by Wei Dai
2
3 // Thanks to Leonard Janke for the suggestion for AutoSeededRandomPool.
4
5 #include "pch.h"
6 #include "config.h"
7
8 #ifndef CRYPTOPP_IMPORTS
9
10 // Win32 has CryptoAPI and <wincrypt.h>. Windows 10 and Windows Store 10 have CNG and <bcrypt.h>.
11 // There's a hole for Windows Phone 8 and Windows Store 8. There is no userland RNG available.
12 // Also see http://www.drdobbs.com/windows/using-c-and-com-with-winrt/240168150 and
13 // http://stackoverflow.com/questions/36974545/random-numbers-for-windows-phone-8-and-windows-store-8 and
14 // https://social.msdn.microsoft.com/Forums/vstudio/en-US/25b83e13-c85f-4aa1-a057-88a279ea3fd6/what-crypto-random-generator-c-code-could-use-on-wp81
15 #if defined(CRYPTOPP_WIN32_AVAILABLE) && !defined(OS_RNG_AVAILABLE)
16 # pragma message("WARNING: Compiling for Windows but an OS RNG is not available. This is likely a Windows Phone 8 or Windows Store 8 app.")
17 #endif
18
19 #if !defined(NO_OS_DEPENDENCE) && defined(OS_RNG_AVAILABLE)
20
21 #include "osrng.h"
22 #include "rng.h"
23
24 // FreeBSD links /dev/urandom -> /dev/random. It showed up when we added
25 // O_NOFOLLOW to harden the non-blocking generator. Use Arc4Random instead
26 // for a non-blocking generator. Arc4Random is cryptographic quality prng
27 // based on ChaCha20. The ChaCha20 generator is seeded from /dev/random,
28 // so we can't completely avoid the blocking.
29 // https://www.freebsd.org/cgi/man.cgi?query=arc4random_buf.
30 #ifdef __FreeBSD__
31 # define DONT_USE_O_NOFOLLOW 1
32 # define USE_FREEBSD_ARC4RANDOM 1
33 # include <stdlib.h>
34 #endif
35
36 // Solaris links /dev/urandom -> ../devices/pseudo/random@0:urandom
37 // We can't access the device. Avoid O_NOFOLLOW for the platform.
38 #ifdef __sun
39 # define DONT_USE_O_NOFOLLOW 1
40 #endif
41
42 // And other OSes that don't define it
43 #ifndef O_NOFOLLOW
44 # define DONT_USE_O_NOFOLLOW 1
45 #endif
46
47 #ifdef CRYPTOPP_WIN32_AVAILABLE
48 #define WIN32_LEAN_AND_MEAN
49 #include <windows.h>
50 #ifndef ERROR_INCORRECT_SIZE
51 # define ERROR_INCORRECT_SIZE 0x000005B6
52 #endif
53 #if defined(USE_MS_CRYPTOAPI)
54 #include <wincrypt.h>
55 #ifndef CRYPT_NEWKEYSET
56 # define CRYPT_NEWKEYSET 0x00000008
57 #endif
58 #ifndef CRYPT_MACHINE_KEYSET
59 # define CRYPT_MACHINE_KEYSET 0x00000020
60 #endif
61 #elif defined(USE_MS_CNGAPI)
62 #include <bcrypt.h>
63 #ifndef BCRYPT_SUCCESS
64 # define BCRYPT_SUCCESS(Status) (((NTSTATUS)(Status)) >= 0)
65 #endif
66 #ifndef STATUS_INVALID_PARAMETER
67 # define STATUS_INVALID_PARAMETER 0xC000000D
68 #endif
69 #ifndef STATUS_INVALID_HANDLE
70 # define STATUS_INVALID_HANDLE 0xC0000008
71 #endif
72 #endif
73 #endif // Win32
74
75 #ifdef CRYPTOPP_UNIX_AVAILABLE
76 #include <errno.h>
77 #include <fcntl.h>
78 #include <unistd.h>
79 #endif
80
81 NAMESPACE_BEGIN(CryptoPP)
82
83 #if defined(NONBLOCKING_RNG_AVAILABLE) || defined(BLOCKING_RNG_AVAILABLE)
84 OS_RNG_Err::OS_RNG_Err(const std::string &operation)
85 : Exception(OTHER_ERROR, "OS_Rng: " + operation + " operation failed with error " +
86 #ifdef CRYPTOPP_WIN32_AVAILABLE
87 "0x" + IntToString(GetLastError(), 16)
88 #else
89 IntToString(errno)
90 #endif
91 )
92 {
93 }
94 #endif
95
96 #ifdef NONBLOCKING_RNG_AVAILABLE
97
98 #ifdef CRYPTOPP_WIN32_AVAILABLE
99
100 #if defined(USE_MS_CNGAPI)
101 inline DWORD NtStatusToErrorCode(NTSTATUS status)
102 {
103 if (status == static_cast<NTSTATUS>(STATUS_INVALID_PARAMETER))
104 return ERROR_INVALID_PARAMETER;
105 else if (status == static_cast<NTSTATUS>(STATUS_INVALID_HANDLE))
106 return ERROR_INVALID_HANDLE;
107 else
108 return static_cast<DWORD>(status);
109 }
110 #endif
111
112 #if defined(UNICODE) || defined(_UNICODE)
113 # define CRYPTOPP_CONTAINER L"Crypto++ RNG"
114 #else
115 # define CRYPTOPP_CONTAINER "Crypto++ RNG"
116 #endif
117
118 MicrosoftCryptoProvider::MicrosoftCryptoProvider() : m_hProvider(0)
119 {
120 #if defined(USE_MS_CRYPTOAPI)
121 // See http://support.microsoft.com/en-us/kb/238187 for CRYPT_NEWKEYSET fallback strategy
122 if (!CryptAcquireContext(&m_hProvider, 0, 0, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
123 {
124 const DWORD firstErr = GetLastError();
125 if (!CryptAcquireContext(&m_hProvider, CRYPTOPP_CONTAINER, 0, PROV_RSA_FULL, CRYPT_NEWKEYSET /*user*/) &&
126 !CryptAcquireContext(&m_hProvider, CRYPTOPP_CONTAINER, 0, PROV_RSA_FULL, CRYPT_MACHINE_KEYSET|CRYPT_NEWKEYSET))
127 {
128 // Set original error with original code
129 SetLastError(firstErr);
130 throw OS_RNG_Err("CryptAcquireContext");
131 }
132 }
133 #elif defined(USE_MS_CNGAPI)
134 NTSTATUS ret = BCryptOpenAlgorithmProvider(&m_hProvider, BCRYPT_RNG_ALGORITHM, MS_PRIMITIVE_PROVIDER, 0);
135 if (!(BCRYPT_SUCCESS(ret)))
136 {
137 // Hack... OS_RNG_Err calls GetLastError()
138 SetLastError(NtStatusToErrorCode(ret));
139 throw OS_RNG_Err("BCryptOpenAlgorithmProvider");
140 }
141 #endif
142 }
143
144 MicrosoftCryptoProvider::~MicrosoftCryptoProvider()
145 {
146 #if defined(USE_MS_CRYPTOAPI)
147 if (m_hProvider)
148 CryptReleaseContext(m_hProvider, 0);
149 #elif defined(USE_MS_CNGAPI)
150 if (m_hProvider)
151 BCryptCloseAlgorithmProvider(m_hProvider, 0);
152 #endif
153 }
154
155 #endif // CRYPTOPP_WIN32_AVAILABLE
156
157 NonblockingRng::NonblockingRng()
158 {
159 #if !defined(CRYPTOPP_WIN32_AVAILABLE) && !defined(USE_FREEBSD_ARC4RANDOM)
160 # ifndef DONT_USE_O_NOFOLLOW
161 const int flags = O_RDONLY|O_NOFOLLOW;
162 # else
163 const int flags = O_RDONLY;
164 # endif
165
166 m_fd = open("/dev/urandom", flags);
167 if (m_fd == -1)
168 throw OS_RNG_Err("open /dev/urandom");
169
170 #endif
171 }
172
173 NonblockingRng::~NonblockingRng()
174 {
175 #if !defined(CRYPTOPP_WIN32_AVAILABLE) && !defined(USE_FREEBSD_ARC4RANDOM)
176 close(m_fd);
177 #endif
178 }
179
180 void NonblockingRng::GenerateBlock(byte *output, size_t size)
181 {
182 #ifdef CRYPTOPP_WIN32_AVAILABLE
183 // Acquiring a provider is expensive. Do it once and retain the reference.
184 # if defined(CRYPTOPP_CXX11_STATIC_INIT)
185 static const MicrosoftCryptoProvider hProvider = MicrosoftCryptoProvider();
186 # else
187 const MicrosoftCryptoProvider &hProvider = Singleton<MicrosoftCryptoProvider>().Ref();
188 # endif
189 # if defined(USE_MS_CRYPTOAPI)
190 DWORD dwSize;
191 CRYPTOPP_ASSERT(SafeConvert(size, dwSize));
192 if (!SafeConvert(size, dwSize))
193 {
194 SetLastError(ERROR_INCORRECT_SIZE);
195 throw OS_RNG_Err("GenerateBlock size");
196 }
197 BOOL ret = CryptGenRandom(hProvider.GetProviderHandle(), dwSize, output);
198 CRYPTOPP_ASSERT(ret != FALSE);
199 if (ret == FALSE)
200 throw OS_RNG_Err("CryptGenRandom");
201 # elif defined(USE_MS_CNGAPI)
202 ULONG ulSize;
203 CRYPTOPP_ASSERT(SafeConvert(size, ulSize));
204 if (!SafeConvert(size, ulSize))
205 {
206 SetLastError(ERROR_INCORRECT_SIZE);
207 throw OS_RNG_Err("GenerateBlock size");
208 }
209 NTSTATUS ret = BCryptGenRandom(hProvider.GetProviderHandle(), output, ulSize, 0);
210 CRYPTOPP_ASSERT(BCRYPT_SUCCESS(ret));
211 if (!(BCRYPT_SUCCESS(ret)))
212 {
213 // Hack... OS_RNG_Err calls GetLastError()
214 SetLastError(NtStatusToErrorCode(ret));
215 throw OS_RNG_Err("BCryptGenRandom");
216 }
217 # endif
218 #else
219
220 # if defined(USE_FREEBSD_ARC4RANDOM)
221 // Cryptographic quality prng based on ChaCha20,
222 // https://www.freebsd.org/cgi/man.cgi?query=arc4random_buf
223 arc4random_buf(output, size);
224 # else
225 while (size)
226 {
227 ssize_t len = read(m_fd, output, size);
228 if (len < 0)
229 {
230 // /dev/urandom reads CAN give EAGAIN errors! (maybe EINTR as well)
231 if (errno != EINTR && errno != EAGAIN)
232 throw OS_RNG_Err("read /dev/urandom");
233
234 continue;
235 }
236 output += len;
237 size -= len;
238 }
239 # endif // USE_FREEBSD_ARC4RANDOM
240
241 #endif // CRYPTOPP_WIN32_AVAILABLE
242 }
243
244 #endif // NONBLOCKING_RNG_AVAILABLE
245
246 // *************************************************************
247
248 #ifdef BLOCKING_RNG_AVAILABLE
249
250 #ifndef CRYPTOPP_BLOCKING_RNG_FILENAME
251 # ifdef __OpenBSD__
252 # define CRYPTOPP_BLOCKING_RNG_FILENAME "/dev/srandom"
253 # else
254 # define CRYPTOPP_BLOCKING_RNG_FILENAME "/dev/random"
255 # endif
256 #endif
257
258 BlockingRng::BlockingRng()
259 {
260 #ifndef DONT_USE_O_NOFOLLOW
261 const int flags = O_RDONLY|O_NOFOLLOW;
262 #else
263 const int flags = O_RDONLY;
264 #endif
265
266 m_fd = open(CRYPTOPP_BLOCKING_RNG_FILENAME, flags);
267 if (m_fd == -1)
268 throw OS_RNG_Err("open " CRYPTOPP_BLOCKING_RNG_FILENAME);
269 }
270
271 BlockingRng::~BlockingRng()
272 {
273 close(m_fd);
274 }
275
276 void BlockingRng::GenerateBlock(byte *output, size_t size)
277 {
278 while (size)
279 {
280 // on some systems /dev/random will block until all bytes
281 // are available, on others it returns immediately
282 ssize_t len = read(m_fd, output, size);
283 if (len < 0)
284 {
285 // /dev/random reads CAN give EAGAIN errors! (maybe EINTR as well)
286 if (errno != EINTR && errno != EAGAIN)
287 throw OS_RNG_Err("read " CRYPTOPP_BLOCKING_RNG_FILENAME);
288
289 continue;
290 }
291
292 size -= len;
293 output += len;
294 if (size)
295 sleep(1);
296 }
297 }
298
299 #endif // BLOCKING_RNG_AVAILABLE
300
301 // *************************************************************
302
303 void OS_GenerateRandomBlock(bool blocking, byte *output, size_t size)
304 {
305 #ifdef NONBLOCKING_RNG_AVAILABLE
306 if (blocking)
307 #endif
308 {
309 #ifdef BLOCKING_RNG_AVAILABLE
310 BlockingRng rng;
311 rng.GenerateBlock(output, size);
312 #endif
313 }
314
315 #ifdef BLOCKING_RNG_AVAILABLE
316 if (!blocking)
317 #endif
318 {
319 #ifdef NONBLOCKING_RNG_AVAILABLE
320 NonblockingRng rng;
321 rng.GenerateBlock(output, size);
322 #endif
323 }
324 }
325
326 void AutoSeededRandomPool::Reseed(bool blocking, unsigned int seedSize)
327 {
328 SecByteBlock seed(seedSize);
329 OS_GenerateRandomBlock(blocking, seed, seedSize);
330 IncorporateEntropy(seed, seedSize);
331 }
332
333 NAMESPACE_END
334
335 #endif // OS_RNG_AVAILABLE
336
337 #endif // CRYPTOPP_IMPORTS
AutoSeededRandomPool::Reseed
void Reseed(bool blocking=false, unsigned int seedSize=32)
Reseed an AutoSeededRandomPool.
BlockingRng
Wrapper class for /dev/random and /dev/srandom.
Definition: osrng.h:120
BlockingRng::GenerateBlock
void GenerateBlock(byte *output, size_t size)
Generate random array of bytes.
BlockingRng::BlockingRng
BlockingRng()
Construct a BlockingRng.
Exception
Base class for all exceptions thrown by the library.
Definition: cryptlib.h:164
MicrosoftCryptoProvider
Definition: osrng.h:39
MicrosoftCryptoProvider::MicrosoftCryptoProvider
MicrosoftCryptoProvider()
Construct a MicrosoftCryptoProvider.
MicrosoftCryptoProvider::GetProviderHandle
ProviderHandle GetProviderHandle() const
Retrieves the provider handle.
Definition: osrng.h:66
NonblockingRng
Wrapper class for /dev/random and /dev/srandom.
Definition: osrng.h:86
NonblockingRng::NonblockingRng
NonblockingRng()
Construct a NonblockingRng.
NonblockingRng::GenerateBlock
void GenerateBlock(byte *output, size_t size)
Generate random array of bytes.
OS_RNG_Err
Exception thrown when an operating system error is encountered.
Definition: osrng.h:26
OS_RNG_Err::OS_RNG_Err
OS_RNG_Err(const std::string &operation)
Constructs an OS_RNG_Err.
RandomPool::IncorporateEntropy
void IncorporateEntropy(const byte *input, size_t length)
Update RNG state with additional unpredictable values.
SecByteBlock
SecBlock<byte> typedef.
Definition: secblock.h:1226
Singleton
Restricts the instantiation of a class to one static object without locks.
Definition: misc.h:309
Singleton::Ref
const T & Ref(...) const
Return a reference to the inner Singleton object.
Definition: misc.h:329
config.h
Library configuration file.
IntToString
std::string IntToString(T value, unsigned int base=10)
Converts a value to a string.
Definition: misc.h:929
SafeConvert
bool SafeConvert(T1 from, T2 &to)
Perform a conversion from from to to.
Definition: misc.h:718
CryptoPP
Crypto++ library namespace.
osrng.h
Classes for access to the operating system's random number generators.
OS_GenerateRandomBlock
CRYPTOPP_DLL void OS_GenerateRandomBlock(bool blocking, byte *output, size_t size)
OS_GenerateRandomBlock.
pch.h
Precompiled header file.
rng.h
Miscellaneous classes for RNGs.
CRYPTOPP_ASSERT
#define CRYPTOPP_ASSERT(exp)
Debugging and diagnostic assertion.
Definition: trap.h:68