Use arc4random()/getrandom() to get random bytes instead of sysctl() interface

1 files changed, 32 insertions, 31 deletions

diff --git a/src/openssl.c b/src/openssl.c
index d8eebb5..6addcaa 100644
--- a/src/openssl.c
+++ b/src/openssl.c
@@ -48,6 +48,19 @@
 
 #if __APPLE__
 #include <mach/mach_time.h> /* mach_absolute_time() */
+#define HAVE_ARC4RANDOM
+#endif
+
+#if defined(__FreeBSD_kernel__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)
+#define HAVE_ARC4RANDOM
+#endif
+
+#if defined(__linux__)
+#include <linux/version.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)
+#define HAVE_GETRANDOM
+#include <linux/random.h>
+#endif
 #endif
 
 #include <openssl/opensslconf.h>
@@ -7811,44 +7824,16 @@ static struct randL_state *randL_getstate(lua_State *L) {
         return lua_touserdata(L, lua_upvalueindex(1));
 } /* randL_getstate() */
 
-#ifndef HAVE_SYS_SYSCTL_H
-#define HAVE_SYS_SYSCTL_H (BSD || __GLIBC__)
-#endif
-
-#if HAVE_SYS_SYSCTL_H
-#include <sys/sysctl.h> /* CTL_KERN KERN_RANDOM RANDOM_UUID KERN_URND KERN_ARND sysctl(2) */
-#endif
-
-#ifndef HAVE_RANDOM_UUID
-#define HAVE_RANDOM_UUID (HAVE_SYS_SYSCTL_H && defined __linux) /* RANDOM_UUID is an enum, not macro */
-#endif
-
-#ifndef HAVE_KERN_URND
-#define HAVE_KERN_URND (defined KERN_URND)
-#endif
-
-#ifndef HAVE_KERN_ARND
-#define HAVE_KERN_ARND (defined KERN_ARND)
-#endif
 
 static int randL_stir(struct randL_state *st, unsigned rqstd) {
         unsigned count = 0;
         int error;
         unsigned char data[256];
-#if HAVE_RANDOM_UUID || HAVE_KERN_URND || HAVE_KERN_ARND
-#if HAVE_RANDOM_UUID
-        int mib[] = { CTL_KERN, KERN_RANDOM, RANDOM_UUID };
-#elif HAVE_KERN_URND
-        int mib[] = { CTL_KERN, KERN_URND };
-#else
-        int mib[] = { CTL_KERN, KERN_ARND };
-#endif
-
-        while (count < rqstd) {
+#if HAVE_ARC4RANDOM
+        while (count < rqst) {
                 size_t n = MIN(rqstd - count, sizeof data);
 
-                if (0 != sysctl(mib, countof(mib), data, &n, (void *)0, 0))
-                        break;
+                arc4random(data, n);
 
                 RAND_add(data, n, n);
 
@@ -7856,6 +7841,22 @@ static int randL_stir(struct randL_state *st, unsigned rqstd) {
         }
 #endif
 
+#if HAVE_GETRANDOM
+        while (count < rqst) {
+                size_t n = MIN(rqstd - count, sizeof data);
+
+                n = getrandom(data, n, 0);
+
+                if (n == -1) {
+                        break;
+                }
+
+                RAND_add(data, n, n);
+
+                count += n;
+        }
+#endif
+
         if (count < rqstd) {
 #if defined O_CLOEXEC && (!defined _AIX /* O_CLOEXEC overflows int */)
                 int fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC);