avoid fork-unsafe arc4random implementations

Some old implementaions of arc4random_buf(3) were ARC4 based, or
unsafe when forked, or both.  Resort to /dev/urandom for those
known problematic cases.  Fix [Bug #15039]

Patch from Thomas Hurst <tom@hur.st>


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64625 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 6 insertions, 0 deletions

diff --git a/random.c b/random.c
index 4add8868fb..9579cfce21 100644
--- a/random.c
+++ b/random.c
@@ -494,8 +494,14 @@ fill_random_bytes_syscall(void *seed, size_t size, int unused)
 static int
 fill_random_bytes_syscall(void *buf, size_t size, int unused)
 {
+#if (defined(__OpenBSD__) && OpenBSD >= 201411) || \
+    (defined(__NetBSD__)  && __NetBSD_Version__ >= 700000000) || \
+    (defined(__FreeBSD__) && __FreeBSD_version >= 1200079)
     arc4random_buf(buf, size);
     return 0;
+#else
+    return -1;
+#endif
 }
 #elif defined(_WIN32)
 static void