Skip to content

Use getrandom() in Linux if it's available #14

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
oittaa wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Use getrandom() in Linux if it's available #14

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
39 changes: 32 additions & 7 deletions src/random/random.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,20 +2,29 @@
* Hardware-based random number generation function
*
* It uses /dev/urandom in Linux and CNG's BCryptGenRandom function in Windows
*********************************************************************************************/
*********************************************************************************************/

#include "random.h"
#include <stdlib.h>
#if defined(__WINDOWS__)
#include <windows.h>
#include <bcrypt.h>
#elif defined(__LINUX__)
#include <unistd.h>
#include <fcntl.h>
static int lock = -1;
#if defined(__has_include)
#if __has_include(<sys/random.h>)
#define HAVE_GETRANDOM 1
#include <sys/random.h>
#include <errno.h>
#endif
#endif
#ifndef HAVE_GETRANDOM
#include <unistd.h>
#include <fcntl.h>
static int lock = -1;
#endif
#endif

#define passed 0
#define passed 0
#define failed 1


Expand All @@ -28,14 +37,29 @@ static __inline void delay(unsigned int count)
int randombytes(unsigned char* random_array, unsigned long long nbytes)
{ // Generation of "nbytes" of random values

#if defined(__WINDOWS__)
#if defined(__WINDOWS__)
if (!BCRYPT_SUCCESS(BCryptGenRandom(NULL, random_array, (unsigned long)nbytes, BCRYPT_USE_SYSTEM_PREFERRED_RNG))) {
return failed;
}

#elif defined(__LINUX__)
int r, n = (int)nbytes, count = 0;

#if defined(HAVE_GETRANDOM)
while (n > 0) {
errno = 0;
r = getrandom(random_array+count, n, 0);
if (r < 0) {
if (errno == EINTR) {
/* retry getrandom() if it was interrupted by a signal */
continue;
}
return failed;
}
count += r;
n -= r;
}
#else /* Not HAVE_GETRANDOM */
if (lock == -1) {
do {
lock = open("/dev/urandom", O_RDONLY);
Expand All @@ -55,7 +79,8 @@ int randombytes(unsigned char* random_array, unsigned long long nbytes)
count += r;
n -= r;
}
#endif /* Not HAVE_GETRANDOM */
#endif

return passed;
}
}