Use arc4random_buf() instead of RAND_bytes() or RAND_pseudo_bytes().

arc4random provides high quality pseudo-random numbers, hence there is no
need to differentiate between "strong" and "pseudo". Furthermore, the
arc4random_buf() function is guaranteed to succeed, which avoids the need
to check for and handle failure, simplifying the code.

It is worth noting that a number of the replaced RAND_bytes() and
RAND_pseudo_bytes() calls were missing return value checks and these
functions can fail for a number of reasons (at least in OpenSSL -
thankfully they were converted to wrappers around arc4random_buf() some
time ago in LibreSSL).

ok beck@ deraadt@ miod@

1 files changed, 3 insertions, 5 deletions

diff --git a/src/lib/libssl/d1_clnt.c b/src/lib/libssl/d1_clnt.c
index 0cc4016d11..4b71f01a6c 100644
--- a/src/lib/libssl/d1_clnt.c
+++ b/src/lib/libssl/d1_clnt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: d1_clnt.c,v 1.35 2014/09/07 12:16:23 jsing Exp $ */
+/* $OpenBSD: d1_clnt.c,v 1.36 2014/10/18 16:13:16 jsing Exp $ */
 /*
  * DTLS implementation written by Nagendra Modadugu
  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
@@ -116,7 +116,6 @@
 #include <stdio.h>
 #include "ssl_locl.h"
 #include <openssl/buffer.h>
-#include <openssl/rand.h>
 #include <openssl/objects.h>
 #include <openssl/evp.h>
 #include <openssl/md5.h>
@@ -779,7 +778,7 @@ dtls1_client_hello(SSL *s)
                 for (i = 0; p[i]=='\0' && i < sizeof(s->s3->client_random); i++)
                         ;
                 if (i == sizeof(s->s3->client_random))
-                        RAND_pseudo_bytes(p, sizeof(s->s3->client_random));
+                        arc4random_buf(p, sizeof(s->s3->client_random));
 
                 /* Do the message type and length last */
                 d = p = &(buf[DTLS1_HM_HEADER_LENGTH]);
@@ -954,8 +953,7 @@ dtls1_send_client_key_exchange(SSL *s)
 
                         tmp_buf[0] = s->client_version >> 8;
                         tmp_buf[1] = s->client_version&0xff;
-                        if (RAND_bytes(&(tmp_buf[2]), sizeof tmp_buf - 2) <= 0)
-                                goto err;
+                        arc4random_buf(&tmp_buf[2], sizeof(tmp_buf) - 2);
 
                         s->session->master_key_length = sizeof tmp_buf;