750063e · typeable/entropy

System/Entropy.hs+30−3

compare with main

unifiedsplit

@@ -16,9 +16,8 @@ module System.Entropy

16 , closeHandle

17 ) where

18

19−import Control.Monad (liftM)

19+import Control.Monad (liftM, when)

20import Data.ByteString as B

21−import Data.ByteString.Lazy as L

22import System.IO (openFile, hClose, IOMode(..), Handle, withBinaryFile)

21import System.IO (openFile, hClose, IOMode(..), Handle, withBinaryFile)

23

22

24#if defined(isWindows)

23#if defined(isWindows)

@@ -114,6 +113,12 @@ hGetEntropy :: CryptHandle -> Int -> IO B.ByteString

114hGetEntropy (CH h) = cryptGenRandom h

113hGetEntropy (CH h) = cryptGenRandom h

115

114

116#else

115#else

116+{- Not windows, assuming nix with a /dev/urandom -}

117+import Foreign.C.Types

118+import Foreign.Ptr

119+import Data.ByteString.Internal as B

120+

121+source :: FilePath

117source = "/dev/urandom"

122source = "/dev/urandom"

118

123

119-- |Handle for manual resource mangement

124-- |Handle for manual resource mangement

@@ -131,6 +136,17 @@ closeHandle (CH h) = hClose h

131hGetEntropy :: CryptHandle -> Int -> IO B.ByteString

136hGetEntropy :: CryptHandle -> Int -> IO B.ByteString

132hGetEntropy (CH h) = B.hGet h

137hGetEntropy (CH h) = B.hGet h

133

138

139+#ifdef arch_x86_64

140+foreign import ccall unsafe "cpu_has_rdrand"

141+ c_cpu_has_rdrand :: IO CInt

142+

143+foreign import ccall unsafe "get_rand_bytes"

144+ c_get_rand_bytes :: Ptr CUChar -> CSize -> IO CInt

145+

146+cpuHasRdRand :: IO Bool

147+cpuHasRdRand = (/= 0) `fmap` c_cpu_has_rdrand

148+#endif

149+

134-- |Inefficiently get a specific number of bytes of cryptographically

150-- |Inefficiently get a specific number of bytes of cryptographically

135-- secure random data using the system-specific facilities.

151-- secure random data using the system-specific facilities.

136--

152--

@@ -138,6 +154,17 @@ hGetEntropy (CH h) = B.hGet h

138-- this entropy is considered "cryptographically secure" but not true

154-- this entropy is considered "cryptographically secure" but not true

139-- entropy.

155-- entropy.

140getEntropy :: Int -> IO B.ByteString

156getEntropy :: Int -> IO B.ByteString

157+getEntropy n = do

158+#if arch_x86_64

159+ b <- cpuHasRdRand

160+ if b then B.create n $ \ptr -> do

161+ r <- c_get_rand_bytes (castPtr ptr) (fromIntegral n)

162+ when (r /= 0)

163+ (fail "RDRand failed to gather entropy")

164+ else do

165+#endif

166+{- arch_x86 -}

141−getEntropy n = withBinaryFile source ReadMode (`B.hGet` n)

167+ withBinaryFile source ReadMode (`B.hGet` n)

142#endif

168#endif

169+{- OS Test -}

143

170

cbits/rdrand.cnew file+51

@@ -0,0 +1,51 @@

1+#include <stdint.h>

2+#include <stdlib.h>

3+

4+int cpu_has_rdrand()

5+{

6+ uint32_t ax,bx,cx,dx,func=1;

7+ __asm__ volatile ("cpuid":\

8+ "=a" (ax), "=b" (bx), "=c" (cx), "=d" (dx) : "a" (func));

9+ return (cx & 0x40000000);

10+}

11+

12+// Returns 1 on success

13+inline int _rdrand64_step(uint64_t *therand)

14+{

15+ unsigned char err;

16+ asm volatile("rdrand %0 ; setc %1"

17+ : "=r" (*therand), "=qm" (err));

18+ return (int) err;

19+}

20+

21+// Returns 0 on success, non-zero on failure.

22+int get_rand_bytes(uint8_t *therand, size_t len)

23+{

24+ int cnt;

25+ int fail=0;

26+ uint8_t *p = therand;

27+ uint8_t *end = therand + len;

28+ if((uint64_t)p%8 != 0) {

29+ uint64_t tmp;

30+ fail |= !_rdrand64_step(&tmp);

31+ while((uint64_t)p%8 != 0 && p != end) {

32+ *p = (uint8_t)(tmp & 0xFF);

33+ tmp = tmp >> 8;

34+ p++;

35+ }

36+ }

37+ for(; p <= end - sizeof(uint64_t); p+=sizeof(uint64_t)) {

38+ fail |= !_rdrand64_step((uint64_t *)p);

39+ }

40+ if(p != end) {

41+ uint64_t tmp;

42+ int cnt;

43+ fail |= !_rdrand64_step(&tmp);

44+ while(p != end) {

45+ *p = (uint8_t)(tmp & 0xFF);

46+ tmp = tmp >> 8;

47+ p++;

48+ }

49+ }

50+ return fail;

51+}

cbits/rdrand.hnew file+10

@@ -0,0 +1,10 @@

1+#ifndef rdrand_h

2+#include <stdint.h>

3+

4+#ifdef arch_x86_64

5+int cpu_has_rdrand()

6+

7+// Returns 0 on success, non-zero on failure.

8+int get_rand_bytes(uint8_t *therand, size_t len)

9+#endif /* arch_x86_64 */

10+#endif // rdrand_h

entropy.cabal+8−3

@@ -1,5 +1,5 @@

1name: entropy

2−version: 0.2.1

2+version: 0.2.2

3license: BSD3

4license-file: LICENSE

5copyright: Thomas DuBuisson <thomas.dubuisson@gmail.com>

@@ -18,14 +18,19 @@ build-type: Simple

18cabal-version: >= 1.6

19tested-with: GHC == 6.12.1

20data-files:

21−extra-source-files:

21+extra-source-files: ./cbits/rdrand.c

22+ , ./cbits/rdrand.h

22

23

23Library

24Library

24 Build-Depends: base == 4.*, bytestring

25 Build-Depends: base == 4.*, bytestring

25− ghc-options:

26+ ghc-options: -Wall -O2

26 hs-source-dirs:

27 hs-source-dirs:

27 exposed-modules: System.Entropy

28 exposed-modules: System.Entropy

28 other-modules:

29 other-modules:

30+ if arch(x86_64)

31+ cpp-options: -Darch_x86_64

32+ c-sources: cbits/rdrand.c

33+ include-dirs: cbits

29 if os(windows)

34 if os(windows)

30 cpp-options: -DisWindows

35 cpp-options: -DisWindows

31 extra-libraries: advapi32

36 extra-libraries: advapi32