110 lines
2.5 KiB
C++
110 lines
2.5 KiB
C++
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#include "il2cpp-config.h"
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#include "pal_platform.h"
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#if IL2CPP_USES_POSIX_CLASS_LIBRARY_PAL
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#define IL2CPP_HAVE_O_CLOEXEC 1
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#include <stdlib.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <stdio.h>
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#include <time.h>
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#include <unistd.h>
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extern "C"
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{
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// Items needed by mscorlib
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IL2CPP_EXPORT void SystemNative_GetNonCryptographicallySecureRandomBytes(uint8_t* buffer, int32_t bufferLength);
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}
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void SystemNative_GetNonCryptographicallySecureRandomBytes(uint8_t* buffer, int32_t bufferLength)
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{
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IL2CPP_ASSERT(buffer != NULL);
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#if IL2CPP_HAVE_ARC4RANDOM_BUF
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arc4random_buf(buffer, (size_t)bufferLength);
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#else
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static volatile int rand_des = -1;
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long num = 0;
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static bool sMissingDevURandom;
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static bool sInitializedMRand;
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if (!sMissingDevURandom)
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{
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if (rand_des == -1)
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{
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int fd;
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do
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{
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#if IL2CPP_HAVE_O_CLOEXEC
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fd = open("/dev/urandom", O_RDONLY, O_CLOEXEC);
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#else
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fd = open("/dev/urandom", O_RDONLY);
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fcntl(fd, F_SETFD, FD_CLOEXEC);
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#endif
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}
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while ((fd == -1) && (errno == EINTR));
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if (fd != -1)
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{
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if (!__sync_bool_compare_and_swap(&rand_des, -1, fd))
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{
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// Another thread has already set the rand_des
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close(fd);
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}
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}
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else if (errno == ENOENT)
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{
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sMissingDevURandom = true;
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}
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}
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if (rand_des != -1)
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{
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int32_t offset = 0;
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do
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{
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ssize_t n = read(rand_des, buffer + offset , (size_t)(bufferLength - offset));
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if (n == -1)
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{
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if (errno == EINTR)
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{
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continue;
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}
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IL2CPP_ASSERT(false && "read from /dev/urandom has failed");
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break;
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}
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offset += n;
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}
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while (offset != bufferLength);
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}
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}
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if (!sInitializedMRand)
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{
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srand48(time(NULL));
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sInitializedMRand = true;
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}
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// always xor srand48 over the whole buffer to get some randomness
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// in case /dev/urandom is not really random
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for (int i = 0; i < bufferLength; i++)
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{
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if (i % 4 == 0)
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{
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num = lrand48();
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}
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*(buffer + i) ^= num;
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num >>= 8;
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}
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#endif // IL2CPP_HAVE_ARC4RANDOM_BUF
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}
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#endif
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