#include #include #include "randombytes.h" long getrandom_impl(void *buf, unsigned int buflen); void randombytes(unsigned char *buffer, unsigned long long length) { long gr_ret; int errorCount = 0; /* * Ensure that the number of bytes requested can fit within * the types we pass to other calls. * * The interface required by randombytes() used by TweetNaCl * does not give us any way to handle errors. However, * no buffer should exceed these amounts. */ if (length > UINT_MAX || length > LONG_MAX) { Tcl_Panic("Buffer length is too large"); } while (length > 0) { gr_ret = getrandom_impl(buffer, length); if (gr_ret < 0) { errorCount++; if (errorCount > 10) { Tcl_Panic("Unable to generate random numbers"); } continue; } errorCount = 0; if (gr_ret == 0) { continue; } buffer += gr_ret; length -= gr_ret; } return; } #if defined(HAVE_GETRANDOM) # ifdef HAVE_SYS_RANDOM_H # include # endif long getrandom_impl(void *buf, unsigned int buflen) { ssize_t gr_ret; gr_ret = getrandom(buf, buflen, 0); return(gr_ret); } #elif defined(HAVE_GETENTROPY) #include long getrandom_impl(void *buf, unsigned int buflen) { int ge_ret; if (buflen > 255) { buflen = 255; } ge_ret = getentropy(buf, buflen); if (ge_ret != 0) { return(-1); } return(buflen); } #elif defined(HAVE_CRYPTGENRANDOM) && 0 #include long getrandom_impl(void *buf, unsigned int buflen) { Tcl_Panic("Incomplete CryptGenRandom"); } #else # ifdef HAVE_SYS_TYPES_H # include # endif # ifdef HAVE_SYS_STAT_H # include # endif # ifdef HAVE_FCNTL_H # include # endif # ifdef HAVE_UNISTD_H # include # endif long getrandom_impl(void *buf, unsigned int buflen) { ssize_t read_ret; long retval; int fd = -1; fd = open("/dev/urandom", O_RDONLY); if (fd < 0) { return(-1); } retval = 0; while (buflen > 0) { read_ret = read(fd, buf, buflen); if (read_ret <= 0) { continue; } buf += read_ret; retval += read_ret; buflen -= read_ret; } close(fd); return(retval); } #endif