1 files changed, 22 insertions, 8 deletions

diff --git a/kex.c b/kex.c
index 8097ab0f2..194a865ad 100644
--- a/kex.c
+++ b/kex.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: kex.c,v 1.48 2002/03/18 17:50:31 provos Exp $");
+RCSID("$OpenBSD: kex.c,v 1.49 2002/03/26 23:14:51 markus Exp $");
 
 #include <openssl/crypto.h>
 
@@ -57,16 +57,15 @@ static void kex_choose_conf(Kex *);
 static void
 kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
 {
-        u_int32_t rand = 0;
         int i;
 
         buffer_clear(b);
-        for (i = 0; i < KEX_COOKIE_LEN; i++) {
-                if (i % 4 == 0)
-                        rand = arc4random();
-                buffer_put_char(b, rand & 0xff);
-                rand >>= 8;
-        }
+        /*
+         * add a dummy cookie, the cookie will be overwritten by
+         * kex_send_kexinit(), each time a kexinit is set
+         */
+        for (i = 0; i < KEX_COOKIE_LEN; i++)
+                buffer_put_char(b, 0);
         for (i = 0; i < PROPOSAL_MAX; i++)
                 buffer_put_cstring(b, proposal[i]);
         buffer_put_char(b, 0);                  /* first_kex_packet_follows */
@@ -152,6 +151,10 @@ kex_finish(Kex *kex)
 void
 kex_send_kexinit(Kex *kex)
 {
+        u_int32_t rand = 0;
+        u_char *cookie;
+        int i;
+
         if (kex == NULL) {
                 error("kex_send_kexinit: no kex, cannot rekey");
                 return;
@@ -161,6 +164,17 @@ kex_send_kexinit(Kex *kex)
                 return;
         }
         kex->done = 0;
+
+        /* generate a random cookie */
+        if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
+                fatal("kex_send_kexinit: kex proposal too short");
+        cookie = buffer_ptr(&kex->my);
+        for (i = 0; i < KEX_COOKIE_LEN; i++) {
+                if (i % 4 == 0)
+                        rand = arc4random();
+                cookie[i] = rand;
+                rand >>= 8;
+        }
         packet_start(SSH2_MSG_KEXINIT);
         packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
         packet_send();