protect the PRG state with a mutex in res_randomid().

ok deraadt@ guenther@ djm@

1 files changed, 13 insertions, 2 deletions

diff --git a/src/lib/libc/net/res_random.c b/src/lib/libc/net/res_random.c
index f0beb7a573..d1cb0a0cf4 100644
--- a/src/lib/libc/net/res_random.c
+++ b/src/lib/libc/net/res_random.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: res_random.c,v 1.17 2008/04/13 00:28:35 djm Exp $ */
+/* $OpenBSD: res_random.c,v 1.18 2013/03/26 17:29:04 eric Exp $ */
 
 /*
  * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
@@ -68,6 +68,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "thread_private.h"
+
 #define RU_OUT          180     /* Time after wich will be reseeded */
 #define RU_MAX          30000   /* Uniq cycle, avoid blackjack prediction */
 #define RU_GEN          2       /* Starting generator */
@@ -225,8 +227,13 @@ u_int
 res_randomid(void)
 {
         struct timeval tv;
+        u_int r;
+        _THREAD_PRIVATE_MUTEX(random);
 
         gettimeofday(&tv, NULL);
+
+        _THREAD_PRIVATE_MUTEX_LOCK(random);
+
         if (ru_counter >= RU_MAX || tv.tv_sec > ru_reseed)
                 res_initid();
 
@@ -234,7 +241,11 @@ res_randomid(void)
         ru_x = (ru_a * ru_x + ru_b) % RU_M;
         ru_counter++;
 
-        return permute15(ru_seed ^ pmod(ru_g, ru_seed2 + ru_x, RU_N)) | ru_msb;
+        r = permute15(ru_seed ^ pmod(ru_g, ru_seed2 + ru_x, RU_N)) | ru_msb;
+
+        _THREAD_PRIVATE_MUTEX_UNLOCK(random);
+
+        return (r);
 }
 
 #if 0